power supply system for negative ion source at ipr - iopscience

13
Journal of Physics: Conference Series OPEN ACCESS Power supply system for negative ion source at IPR To cite this article: Agrajit Gahlaut et al 2010 J. Phys.: Conf. Ser. 208 012030 View the article online for updates and enhancements. Related content System integration of RF based negative ion experimental facility at IPR G Bansal, M Bandyopadhyay, M J Singh et al. - Development of 8 MW Power Supply Based on Pulse Step Modulation Technique for Auxiliary Heating System on HL-2A Xu Weidong, Xuan Weimin, Yao Lieying et al. - Development of 70kV, 22A DC power supply for High Power RF and microwave tubes Y S S Srinivas, Rajan Babu, Azad Makwana et al. - Recent citations System upgradation for surface mode negative ion beam extraction experiments in ROBIN Kaushal Pandya et al - Negative ion beam extraction in ROBIN Gourab Bansal et al - This content was downloaded from IP address 58.235.151.181 on 21/08/2021 at 04:54

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Page 1: Power supply system for negative ion source at IPR - IOPscience

Journal of Physics Conference Series

OPEN ACCESS

Power supply system for negative ion source atIPRTo cite this article Agrajit Gahlaut et al 2010 J Phys Conf Ser 208 012030

View the article online for updates and enhancements

Related contentSystem integration of RF based negativeion experimental facility at IPRG Bansal M Bandyopadhyay M J Singhet al

-

Development of 8 MW Power SupplyBased on Pulse Step ModulationTechnique for Auxiliary Heating System onHL-2AXu Weidong Xuan Weimin Yao Lieying etal

-

Development of 70kV 22A DC powersupply for High Power RF and microwavetubesY S S Srinivas Rajan Babu AzadMakwana et al

-

Recent citationsSystem upgradation for surface modenegative ion beam extraction experimentsin ROBINKaushal Pandya et al

-

Negative ion beam extraction in ROBINGourab Bansal et al

-

This content was downloaded from IP address 58235151181 on 21082021 at 0454

Power supply system for Negative Ion Source at IPR

Agrajit Gahlaut Jashwant Sonara K G Parmar Jignesh Soni M Bandyopadhyay Mahendrajit Singh Gourab Bansal Kaushal Pandya and Arun Chakraborty

Institute for Plasma Research Gandhinagar Gujarat ndash 382428 India

agrajitiprresin

Abstract The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly ndash RF based where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ~5 x 1012 cm-3 from which ~ 10 A of negative ion beam shall be produced and accelerated to 35 kV through an electrostatic ion accelerator The experimental system is modelled similar to the RF based negative ion source BATMAN presently operating at IPP Garching Germany The mechanical system for Negative Ion Source Assembly is close to the IPP source remaining systems are designed and procured principally from indigenous sources keeping the IPP configuration as a base line High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup The HV power supplies for extraction and acceleration are rated for high voltage (~15 to 35kV) and high current (~ 15 to 35A) Other attributes are fast rate of voltage rise (lt 5ms) good regulation (lt plusmn1) low ripple (lt plusmn2) isolation (~50kV) low energy content (lt 10J) and fast cut-off (lt 100micros) The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids have attributes of low ripple high stability fast and precise regulation programmability and remote operation These power supplies are also equipped with over-voltage over-current and current limit (CC Mode) protections Fault diagnostics to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme To restrict the fault energy deposited on the ion source specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy Moreover the monitoring status and control signals from these power supplies are required to be electrically (~ 50kV) isolated from the system The paper shall present the design basis topology selection manufacturing testing commissioning integration and control strategy of these HVPS A complete power interconnection scheme which includes all protective devices and measuring devices low amp high voltage power supplies monitoring and control signals etc shall also be discussed The paper also discusses the protocols involved in grounding and shielding particularly in operating the system in RF environment

1 Introduction RF based negative ion facility is currently under development in IPR [1] For the operation of such a facility various power supplies are required as shown in lsquoFigure 1rsquo Since the negative ion source assembly at IPR is similar to the ion source at IPP the majority of the specifications are derived from this already existing system

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

ccopy 2010 IOP Publishing Ltd 1

Figure 1 Block diagram of power supply system for negative ion source at IPR

Plasma is produced by an oscillator RF generator which utilizes a separate power supply to drive the oscillator The power supply for the RF generator is a bought out item and is not discussed in this paper Regulated High Voltage Power Supplies (RHVPS) with low energy content fast rise time and various other critical parameters are required for the process of Extraction and Acceleration which are discussed later in this paper These Power supplies should be remotely operated and equipped with all necessary protective devices for the safety of the power supply as well as the source A passive protection scheme (Snubber) will also be incorporated which will provide protection against the grid breakdowns In addition to this various other isolated low to medium power heating and bias power supplies are required for beam production and control This includes Filament Bias Filament Heating Grid Bias and Grid Heating power supplies The Filament circuit assists in plasma generation Plasma Grid and Bias circuit is used for electron suppression The input power to these power supplies will be fed through MCB based sub-distribution panels housed with necessary electrical protection devices A 50kV DC isolation transformer will be used to feed the AC power to the power supplies which are floating at the source potential To avoid grounding problems like the ground loops and the noise pickups a star point based grounding scheme has been designed A complete power interconnection and integration scheme is designed showing all the power supplies protecting amp measuring devices and all the control and monitoring signals

2 Ion source High Voltage Power Supplies (HVPS) The high voltage system for the negative ion source consists of the following two power supplies

bull Extraction HVPS for extracting the negative ion bull Acceleration HVPS for accelerating the beam

The common characteristics of these power supplies are isolation from ground regulation low ripple amplitude and dynamic response of few milli seconds Moreover the HVPS power supplies (accelerator and extraction) should trip within 100micros in case of grid breakdown which is a common

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

2

phenomena occurring frequently during source operation The typical ratings of the extraction and acceleration HVPS are shown in table 1 and 2 respectively

Table 1 Ratings of Extraction HVPS Parameter Value Output Voltage 15kV (Floating) Output Current 35A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt

Table 2 Ratings of Acceleration HVPS Parameter Value Output Voltage - 35kV (grounded) Output Current 15A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt

Three major power supply topologies are explored to generate the regulated high voltage DC This

include

bull AC thyristorized power controller based topology (lsquoFigure 2rsquo) bull PWMPSM based RHVPS (lsquoFigure 3rsquo) bull Rectifier inverter based topology (lsquoFigure 4rsquo)

The AC thyristorized based topology (lsquoFigure 2rsquo) uses a combination of power-controller followed

by a step up transformer and controlled rectifier

Figure 2 AC thyristorized power controller based topology with series switch

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

3

The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules

Figure 3 PWMPSM based RHVPS with multi-secondary transformer

Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The

output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system

Figure 4 Rectifier inverter based topology with High frequency transformer

Technical comparison of the all the three technologies is tabulated in table 3

Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices

Yes Yes No

Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR

Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

4

Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices

lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation

Figure 5 Integration and measurement scheme for HVPS

High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is

rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros

Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

5

Figure 6 The cut-off and turn-on sequence of HVPS during breakdown

A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo

Figure 7 Typical Scheme for Grid Breakdowns and over-current detection

The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and

compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)

Figure 8 (a) Startup procedure of HVPS

Figure 8 (b) Operational procedure of HVPS

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

6

3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure

31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies

Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current

Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON

32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm

Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

7

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 2: Power supply system for negative ion source at IPR - IOPscience

Power supply system for Negative Ion Source at IPR

Agrajit Gahlaut Jashwant Sonara K G Parmar Jignesh Soni M Bandyopadhyay Mahendrajit Singh Gourab Bansal Kaushal Pandya and Arun Chakraborty

Institute for Plasma Research Gandhinagar Gujarat ndash 382428 India

agrajitiprresin

Abstract The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly ndash RF based where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ~5 x 1012 cm-3 from which ~ 10 A of negative ion beam shall be produced and accelerated to 35 kV through an electrostatic ion accelerator The experimental system is modelled similar to the RF based negative ion source BATMAN presently operating at IPP Garching Germany The mechanical system for Negative Ion Source Assembly is close to the IPP source remaining systems are designed and procured principally from indigenous sources keeping the IPP configuration as a base line High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup The HV power supplies for extraction and acceleration are rated for high voltage (~15 to 35kV) and high current (~ 15 to 35A) Other attributes are fast rate of voltage rise (lt 5ms) good regulation (lt plusmn1) low ripple (lt plusmn2) isolation (~50kV) low energy content (lt 10J) and fast cut-off (lt 100micros) The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids have attributes of low ripple high stability fast and precise regulation programmability and remote operation These power supplies are also equipped with over-voltage over-current and current limit (CC Mode) protections Fault diagnostics to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme To restrict the fault energy deposited on the ion source specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy Moreover the monitoring status and control signals from these power supplies are required to be electrically (~ 50kV) isolated from the system The paper shall present the design basis topology selection manufacturing testing commissioning integration and control strategy of these HVPS A complete power interconnection scheme which includes all protective devices and measuring devices low amp high voltage power supplies monitoring and control signals etc shall also be discussed The paper also discusses the protocols involved in grounding and shielding particularly in operating the system in RF environment

1 Introduction RF based negative ion facility is currently under development in IPR [1] For the operation of such a facility various power supplies are required as shown in lsquoFigure 1rsquo Since the negative ion source assembly at IPR is similar to the ion source at IPP the majority of the specifications are derived from this already existing system

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

ccopy 2010 IOP Publishing Ltd 1

Figure 1 Block diagram of power supply system for negative ion source at IPR

Plasma is produced by an oscillator RF generator which utilizes a separate power supply to drive the oscillator The power supply for the RF generator is a bought out item and is not discussed in this paper Regulated High Voltage Power Supplies (RHVPS) with low energy content fast rise time and various other critical parameters are required for the process of Extraction and Acceleration which are discussed later in this paper These Power supplies should be remotely operated and equipped with all necessary protective devices for the safety of the power supply as well as the source A passive protection scheme (Snubber) will also be incorporated which will provide protection against the grid breakdowns In addition to this various other isolated low to medium power heating and bias power supplies are required for beam production and control This includes Filament Bias Filament Heating Grid Bias and Grid Heating power supplies The Filament circuit assists in plasma generation Plasma Grid and Bias circuit is used for electron suppression The input power to these power supplies will be fed through MCB based sub-distribution panels housed with necessary electrical protection devices A 50kV DC isolation transformer will be used to feed the AC power to the power supplies which are floating at the source potential To avoid grounding problems like the ground loops and the noise pickups a star point based grounding scheme has been designed A complete power interconnection and integration scheme is designed showing all the power supplies protecting amp measuring devices and all the control and monitoring signals

2 Ion source High Voltage Power Supplies (HVPS) The high voltage system for the negative ion source consists of the following two power supplies

bull Extraction HVPS for extracting the negative ion bull Acceleration HVPS for accelerating the beam

The common characteristics of these power supplies are isolation from ground regulation low ripple amplitude and dynamic response of few milli seconds Moreover the HVPS power supplies (accelerator and extraction) should trip within 100micros in case of grid breakdown which is a common

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

2

phenomena occurring frequently during source operation The typical ratings of the extraction and acceleration HVPS are shown in table 1 and 2 respectively

Table 1 Ratings of Extraction HVPS Parameter Value Output Voltage 15kV (Floating) Output Current 35A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt

Table 2 Ratings of Acceleration HVPS Parameter Value Output Voltage - 35kV (grounded) Output Current 15A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt

Three major power supply topologies are explored to generate the regulated high voltage DC This

include

bull AC thyristorized power controller based topology (lsquoFigure 2rsquo) bull PWMPSM based RHVPS (lsquoFigure 3rsquo) bull Rectifier inverter based topology (lsquoFigure 4rsquo)

The AC thyristorized based topology (lsquoFigure 2rsquo) uses a combination of power-controller followed

by a step up transformer and controlled rectifier

Figure 2 AC thyristorized power controller based topology with series switch

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

3

The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules

Figure 3 PWMPSM based RHVPS with multi-secondary transformer

Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The

output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system

Figure 4 Rectifier inverter based topology with High frequency transformer

Technical comparison of the all the three technologies is tabulated in table 3

Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices

Yes Yes No

Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR

Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

4

Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices

lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation

Figure 5 Integration and measurement scheme for HVPS

High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is

rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros

Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

5

Figure 6 The cut-off and turn-on sequence of HVPS during breakdown

A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo

Figure 7 Typical Scheme for Grid Breakdowns and over-current detection

The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and

compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)

Figure 8 (a) Startup procedure of HVPS

Figure 8 (b) Operational procedure of HVPS

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

6

3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure

31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies

Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current

Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON

32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm

Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

7

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 3: Power supply system for negative ion source at IPR - IOPscience

Figure 1 Block diagram of power supply system for negative ion source at IPR

Plasma is produced by an oscillator RF generator which utilizes a separate power supply to drive the oscillator The power supply for the RF generator is a bought out item and is not discussed in this paper Regulated High Voltage Power Supplies (RHVPS) with low energy content fast rise time and various other critical parameters are required for the process of Extraction and Acceleration which are discussed later in this paper These Power supplies should be remotely operated and equipped with all necessary protective devices for the safety of the power supply as well as the source A passive protection scheme (Snubber) will also be incorporated which will provide protection against the grid breakdowns In addition to this various other isolated low to medium power heating and bias power supplies are required for beam production and control This includes Filament Bias Filament Heating Grid Bias and Grid Heating power supplies The Filament circuit assists in plasma generation Plasma Grid and Bias circuit is used for electron suppression The input power to these power supplies will be fed through MCB based sub-distribution panels housed with necessary electrical protection devices A 50kV DC isolation transformer will be used to feed the AC power to the power supplies which are floating at the source potential To avoid grounding problems like the ground loops and the noise pickups a star point based grounding scheme has been designed A complete power interconnection and integration scheme is designed showing all the power supplies protecting amp measuring devices and all the control and monitoring signals

2 Ion source High Voltage Power Supplies (HVPS) The high voltage system for the negative ion source consists of the following two power supplies

bull Extraction HVPS for extracting the negative ion bull Acceleration HVPS for accelerating the beam

The common characteristics of these power supplies are isolation from ground regulation low ripple amplitude and dynamic response of few milli seconds Moreover the HVPS power supplies (accelerator and extraction) should trip within 100micros in case of grid breakdown which is a common

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

2

phenomena occurring frequently during source operation The typical ratings of the extraction and acceleration HVPS are shown in table 1 and 2 respectively

Table 1 Ratings of Extraction HVPS Parameter Value Output Voltage 15kV (Floating) Output Current 35A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt

Table 2 Ratings of Acceleration HVPS Parameter Value Output Voltage - 35kV (grounded) Output Current 15A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt

Three major power supply topologies are explored to generate the regulated high voltage DC This

include

bull AC thyristorized power controller based topology (lsquoFigure 2rsquo) bull PWMPSM based RHVPS (lsquoFigure 3rsquo) bull Rectifier inverter based topology (lsquoFigure 4rsquo)

The AC thyristorized based topology (lsquoFigure 2rsquo) uses a combination of power-controller followed

by a step up transformer and controlled rectifier

Figure 2 AC thyristorized power controller based topology with series switch

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

3

The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules

Figure 3 PWMPSM based RHVPS with multi-secondary transformer

Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The

output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system

Figure 4 Rectifier inverter based topology with High frequency transformer

Technical comparison of the all the three technologies is tabulated in table 3

Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices

Yes Yes No

Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR

Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

4

Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices

lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation

Figure 5 Integration and measurement scheme for HVPS

High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is

rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros

Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

5

Figure 6 The cut-off and turn-on sequence of HVPS during breakdown

A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo

Figure 7 Typical Scheme for Grid Breakdowns and over-current detection

The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and

compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)

Figure 8 (a) Startup procedure of HVPS

Figure 8 (b) Operational procedure of HVPS

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

6

3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure

31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies

Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current

Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON

32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm

Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

7

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 4: Power supply system for negative ion source at IPR - IOPscience

phenomena occurring frequently during source operation The typical ratings of the extraction and acceleration HVPS are shown in table 1 and 2 respectively

Table 1 Ratings of Extraction HVPS Parameter Value Output Voltage 15kV (Floating) Output Current 35A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt

Table 2 Ratings of Acceleration HVPS Parameter Value Output Voltage - 35kV (grounded) Output Current 15A Output Voltage Rise time lt 5ms Cut-off time during Fault lt 100micros ldquoWire testrdquo clearance value le 10J Maximum output allowable ripple at full load lt plusmn 2 of maximum value Voltage Regulation lt plusmn 1 Normal operating range (NOR) 0-100 Best Control Range 10-100 DC Isolation level 50kV Voltage and current measurement accuracies lt 1 Protections Over Voltage Over Current didt

Three major power supply topologies are explored to generate the regulated high voltage DC This

include

bull AC thyristorized power controller based topology (lsquoFigure 2rsquo) bull PWMPSM based RHVPS (lsquoFigure 3rsquo) bull Rectifier inverter based topology (lsquoFigure 4rsquo)

The AC thyristorized based topology (lsquoFigure 2rsquo) uses a combination of power-controller followed

by a step up transformer and controlled rectifier

Figure 2 AC thyristorized power controller based topology with series switch

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

3

The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules

Figure 3 PWMPSM based RHVPS with multi-secondary transformer

Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The

output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system

Figure 4 Rectifier inverter based topology with High frequency transformer

Technical comparison of the all the three technologies is tabulated in table 3

Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices

Yes Yes No

Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR

Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

4

Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices

lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation

Figure 5 Integration and measurement scheme for HVPS

High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is

rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros

Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

5

Figure 6 The cut-off and turn-on sequence of HVPS during breakdown

A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo

Figure 7 Typical Scheme for Grid Breakdowns and over-current detection

The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and

compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)

Figure 8 (a) Startup procedure of HVPS

Figure 8 (b) Operational procedure of HVPS

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

6

3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure

31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies

Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current

Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON

32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm

Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

7

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 5: Power supply system for negative ion source at IPR - IOPscience

The PWMPSM based RHVPS (lsquoFigure 3rsquo) utilizes a multi-secondary step-up high power transformer The output of each secondary is rectified and controlled independently with a DC-DC converter operating in PWMPSM mode Each DC-DC converter output is connected in series to get the final output The switching of each module is shifted by 360n degree where lsquonrsquo represents the number of modules

Figure 3 PWMPSM based RHVPS with multi-secondary transformer

Rectifier inverter based topology (lsquoFigure 4rsquo) utilizes a high frequency step-up transformer The

output of the transformer can be single (for 6-pulse) or multi (for 12-pulse) A switching frequency of 2kHz is enough to achieve the desirable parameters [2] and hence amorphous cores can be easily used to form the transformers but the frequency can be raised upto10-20kHz depending on the ratings and design of the control system

Figure 4 Rectifier inverter based topology with High frequency transformer

Technical comparison of the all the three technologies is tabulated in table 3

Table 3 Technical comparison between high voltage power supplies Parameter AC Thyristorized RHVPS Rectifier Inverter Technology Simple Complicated Complicated Control Simple Complicated Relatively simple Series switch Required Not required Not required Control speed Slow Fast Fast Energy content High Low Low Transformer design Less critical Critical Less critical Synchronizing skills Less More Less HV stresses on semiconductor devices

Yes Yes No

Inrush current Less More Less Size Bulky Bulky Relatively small Based on the preliminary investigation (as shown in table 3) the rectifier-inverter based topology has been proposed but detailed design analysis and simulations need to be performed before finalizing the topology for its use in the negative ion system at IPR

Both Extraction and Acceleration HVPS power supplies will be tailored made in Industry The power supply will consist of the following sub-sections (1) Power unit (2) Control unit and (3)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

4

Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices

lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation

Figure 5 Integration and measurement scheme for HVPS

High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is

rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros

Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

5

Figure 6 The cut-off and turn-on sequence of HVPS during breakdown

A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo

Figure 7 Typical Scheme for Grid Breakdowns and over-current detection

The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and

compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)

Figure 8 (a) Startup procedure of HVPS

Figure 8 (b) Operational procedure of HVPS

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

6

3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure

31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies

Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current

Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON

32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm

Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

7

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 6: Power supply system for negative ion source at IPR - IOPscience

Remote control unit Based on the topology selected the Power unit will perform the function of AC to DC conversion The unit will be composed of transformer rectifier High frequencyLow frequency step up power transformer switch mode inverter and filter circuits The unit will also be equipped with protective sensing devices like current transducers potential dividers and protection relays Control unit will form the feedback loop for regulation and control of the power supply All the essential voltage and current signals will be communicated through FO links between power and control units for reliable and isolated signal transfer The control unit will be composed of a DSPu-processor based PID feedback control which will generate the control pulses for the switching devices

lsquoFigure 5rsquo shows a typical integration and measurement scheme of the high voltage power supplies to the source It can be seen that the Extraction HVPS is floating over the acceleration HVPS and therefore needs special consideration for DC isolation

Figure 5 Integration and measurement scheme for HVPS

High voltage coaxial conductor RG-220 is planned for making the HV connections The cable is

rated for 100kV DC and 50A A 60kV Tri-axial cable is also explored for making the HV connections The voltage measurements will be performed through 5000x10000x 60kV non-inductive dividers which will be connected at both - the power supply terminals and before the load to ensure proper transmission of voltage The current measurements will be performed through Hall effect type DC current transducers with response faster than 10micros

Grid breakdown is a common phenomenon in the source when operated with HV Both HVPS are allowed to pass a definite number of breakdowns before the final trip of the system can occur During each breakdown the power supply will be following a typical cut-off scheme as shown in lsquoFigure 6rsquo At the occurrence of breakdown the current rises to the peak value governed by the total series impedance The passive snubbers further restrict this to an allowable value close to 1kA This is followed by a breakdown detection and current quench routine which should end within 100micros The power supply is given a rest period of about 15ms This is followed by the turn-on sequence which is of the order of few milli seconds (1msec)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

5

Figure 6 The cut-off and turn-on sequence of HVPS during breakdown

A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo

Figure 7 Typical Scheme for Grid Breakdowns and over-current detection

The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and

compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)

Figure 8 (a) Startup procedure of HVPS

Figure 8 (b) Operational procedure of HVPS

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

6

3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure

31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies

Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current

Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON

32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm

Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

7

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 7: Power supply system for negative ion source at IPR - IOPscience

Figure 6 The cut-off and turn-on sequence of HVPS during breakdown

A typical grid breakdown and over-current detection scheme is proposed as shown in lsquoFigure 7rsquo

Figure 7 Typical Scheme for Grid Breakdowns and over-current detection

The scheme utilizes non-inductive resistor as a current-shunt The output signal is amplified and

compared with a reference to generate a TTL output The total electronics float at the high potential The TTL is converted into light through a TTL to Light converter and is transmitted to a breakdown counter Maximum breakdown count value of 10 is proposed for the HVPS for the operation with ion source The typical breakdown mechanism algorithm along with the HVPS startup and operational algorithm is depicted in lsquoFigure 8rsquo (a) and (b)

Figure 8 (a) Startup procedure of HVPS

Figure 8 (b) Operational procedure of HVPS

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

6

3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure

31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies

Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current

Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON

32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm

Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

7

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 8: Power supply system for negative ion source at IPR - IOPscience

3 Heating and Bias power supplies Various heating amp bias power supplies will be required to aid in beam production amp beam control Each power supply is described briefly for its application typical rating and the start-upoperational procedure

31 Filament heater and filament bias power supplies Both the power supplies are used for plasma production Both the power supplies float at the source potential (50kV maximum) and operate in a 100kW 1MHz RF environment Table 4 and table 5 shows the typical ratings of these power supplies

Table 4 Ratings of filament heater power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-16VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Temperature coefficient le 500ppmoC Duty Cycle Continuous (100) Mode of Operation Constant Voltage and Current

Table 5 Ratings of filament bias power supply Parameter ValueRating Output Voltage (Vout) 90VDC (Battery generated) Output current 05A Auxiliary input voltage 1-ph 230V 50Hz ONOFF Control TTLPFC Current Monitoring 0-5V for 0 to FS ONOFF Status 0V for OFF 5V for ON

32 Grid heating power supply This power supply is used to electrically heat the plasma grid This is also floating at the source potential It should maintain a temperature of 150 oC in the plasma gird which is controlled by the DAC system through a PID control loop Table 6 gives the typical ratings of this power supply and lsquoFigure 9rsquo illustrates the typical startup and operational algorithm

Table 6 Ratings of grid heating power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-65VDC Output current 0-10A Output Voltage Ripple le 5mV p-p Output Voltage Stability le 50mV Output current stability le 1mA Regulation for 80-100 Load le 100micros Programmability Externally through 0-10V signal Mode of Operation Constant Voltage and Current

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

7

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 9: Power supply system for negative ion source at IPR - IOPscience

Figure 9 Startup and Operation algorithm of Grid heating power supply

Figure 10 Startup and Operation algorithm of Grid bias power supply

Figure 11 Startup and Operation algorithm Cs oven power supply

33 Grid bias power supply This power supply is used to bias the plasma grid with respect to the source This essentially controls the electron current This power supply also floats at the source potential Table 7 gives the typical rating of this power supply and lsquoFigure 10rsquo illustrates the typical operational sequence

Table 7 Ratings of grid bias power supply Parameter ValueRating Input Voltage (Vin) 1-phase 230V Input frequency 50Hz Output Voltage (Vout) 0-30VDC Output current 0-66A Output Voltage Ripple le 75mV p-p Output Voltage Stability le 005 Line and load regulation le 01 (V) and 05 (I) Programmability Externally through 0-10v signal Mode of Operation Constant Voltage and Current Voltage monitoring signal 0-10V DC for 0 to 100 of V Current monitoring signal 0-10V DC for 0 to 100 of I

34 Cs oven power supply This power supply is used to Cs oven power supply feeds the heater coils of the Cs oven It is typically rated for 40V and 12A AC It is PID temperature controlled through DAC system lsquoFigure 11rsquo illustrates the typical startup procedure for this power supply

4 Typical interconnection scheme for various power supplies Table 8 gives the description of the output terminal connections for all the power supplies lsquoFigure 12rsquo depicts this pictorially

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

8

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 10: Power supply system for negative ion source at IPR - IOPscience

Table 8 Output terminal connections for all the power supplies Power Supply Positive Terminal Negative

Terminal Accelerator HVPS Ground Extraction Grid Extraction HVPS Extraction Grid Plasma Grid Filament Heater Filament lead 1 Filament lead 2 Filament Bias Source Filament lead2 Grid Heater Grid heater lead 1 Grid heater lead 2 Grid Bias Plasma Grid Source Cs oven PS (Connected to the Cs oven)

Figure 12 Power supply output connections

5 Passive protection scheme for grid breakdown Grid breakdown in grid system of the source is a common phenomenon which occur because of many different conditions of the electrode surface gas pressure and beam optics during the operation [3][4] This is characterized by the fast discharge of energy stored in the stray capacitance of HV cables etc The timescale of the breakdown is beyond the scope of any active protection A suitable passive protection component (Snubber) should be incorporated in the High voltage line in order to protect the load

Figure 13 Typical passive protection scheme (snubber) for grid breakdowns

As shown in lsquoFigure 13rsquo snubber consists of a hollow cylinder of ferromagnetic material

surrounding the high voltage conductor A resistor may act as secondary winding of the snubber providing power dissipation Moreover a bias circuit can be included to increase the available flux swing before core saturation In circuit terms a core snubber is represented by a saturable inductance and a resistance connected in parallel

The snubber parameters can be calculated form the following mathematical relation

CRL timestimes= 24 (1)

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

9

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 11: Power supply system for negative ion source at IPR - IOPscience

where L is the snubber inductance (H) R is the parallel snubber resistance (ohm) and C is the stray capacitance (F) The value of R is governed by the maximum system voltage and the peak fault current and is independent of all other snubber parameters C accounts for the stored energy (capacitance) in the DC cable and the other stray capacitances As shown in lsquoFigure 5rsquo two snubbers will be used in the HV line for the protection against the plasma grid as well as extraction grid breakdown

6 Grounding scheme lsquoFigure 14rsquo depicts a typical grounding scheme for the negative ion system at IPR

Figure 14 Typical grounding scheme for the negative ion system at IPR

The grounding will be as per IS 3043-1987 lsquoCode of practice of earthingrsquo and IS 732-1989 lsquoCode of practice for electrical wiring installationsrsquo All the needed ground connections should terminate at one point called the star point or the main ground connection point Formation of ground loops will to be avoided to the maximum possible extent This will be ensured by grounding only one end of the ground sheath of the cable at the relevant end On the other end the ground sheath should be peeled off

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

10

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 12: Power supply system for negative ion source at IPR - IOPscience

to a certain length and only the central cable should be used for the main connection All the terminations hydraulic or electrical adaptors vacuum gauges pumps etc will be isolated All the electronics related to the diagnostic set ups including the signal processing modules various power supplies gauges etc at the source end will be isolated from the ground for the reason that they are at the source potential The ground connection of the racks containing these modules will also be connected to the star point On the data acquisition end the racks containing the data acquisition modules signal-processing modules etc will be physically isolated from the ground The ground connection for these racks as well as the modules needs to be routed again from the star point

7 Shielding scheme The experimental area housing the RF generator the matching network the isolation transformer and source part upto the plasma box in the negative ion system will shielded inside a cage made of aluminum mesh sheets This is to avoid the radiations of the order ~ 150 Vm from the source to affect the personnel working in the periphery of the experimental setup Moreover such kind of field strengths can completely corrupt the signals and the electronics for measurement and control As the experimental site at IPR is surrounded by the power supplies of the SST-1 additional shielding using the same Aluminum mesh (4 mm thick strips with 8mm gap between individual strip) is required for the area housing the data acquisition and control racks and computers etc lsquoFigure 15rsquo depicts the typical shielding scheme alongwith its grounding proposed for the negative ion system at IPR

Figure 15 Proposed shielding scheme for negative ion system at IPR Measurement using the radiation meter will be performed at the IPR experimental setup once the RF has been switched on to ensure that the radiation levels are limited within the allowable value (132 Vm near vacuum chamber and 3 Vm near the DAC racks)

8 Detailed power supply interconnection scheme lsquoFigure 16rsquo depicts the detailed power supply interconnection scheme including the measuring equipments protection devices and auxiliary power supplies The input isolation transformer connections are also shown This scheme will ensure reliable connection and easy troubleshooting during the commissioning stage of the negative ion system at IPR

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

11

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12

Page 13: Power supply system for negative ion source at IPR - IOPscience

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

16V 10A DC POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-16VDC 10A+

-

230v50Hz

~

~

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

90VDC 500mA+

-

230v50Hz

~

~

+

-

5V

RETURN

5V24V

0V

DCCT 0-5v 0-1A

+ - + -

+ - + -

+ - + -

+ - + -

+ - + -

9V 9V

9V 9V

9V 9V

9V 9V

9V 9V

FILAMENT BIAS POWER SUPPLY

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

30V 66A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFF

0V

0-30VDC 66A+

-

230v50Hz

~

~

ACC - S218 1A

+

-

4V

RETURN

4V+15V0V

DCCT 0-4v 0-100ALEM HAL 100-S

15v DCPS+

-

15v

0v

~

~

230v50Hz

-15V

15v

+-

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

RF FAST IL CARD

GRID BIAS POWER SUPPLY

FILAMENT HEATER POWER SUPPLY

TTL LOW - OSC OFF HIGH - OSC ON

TX

TX

RX

RX

REMOTE PFC-ON - 56 OPTION -A FOR ON (NO STATUS)

OPTION -B FOR ON (WITH STATUS)

24v DCPS+

-

24v

0v

~

~

230v50Hz

P

N

100k1k

LED

65V 10A DC POWER SUPPLY

GRID BIAS POWER SUPPLY

~

~

+

-

230v50Hz

V

V-SET

I

I-SET

AUXCONTACT

16A POWER CONTACTOR

K

24V

SNUBBERPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

COM

STATUS

STATUS = 24V PS ONSTATUS = 0V PS OFF

0V

0-65VDC 10A+

-

230v50Hz

~

~

V-MONCOM

I-MONCOM

V-SETCOM

I-SETCOM

GRID HEATING POWER SUPPLY

TX

TX

RX

RX

MSNUAL LOCALREMOTE SWITCH(INBUILT IN PS)

P N

P N

PLASMA GRID

EXTRACTION GRID

EARTH GRID

TX

P N

P N

REGULATED HVPS

(EXTRACTION)

15kV 35A

REGULATED HVPS

(ACCELERATOR)

35kV 15A

+

-

+

-

12v 60kv5000X DIVIDER

35kV = 7V

12v 60kv5000X DIVIDER

35kV = 7V

I-ion

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA15A = 15mA

15mA x 30E = 045v

I-erd

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

TX

P N

200A 200mA

5A x 10 TURNS = 50A --gt 50mA

50mA x 30E = 15v

10 TURNS

I-elec

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA20A = 20mA

20mA x 30E = 06v

12v 60kv

5000X DIVIDER

50kV = 10V

12v 60kv

5000X DIVIDER

50kV = 10V

I-drain

30E

15v DCPS+

-

15v

0v

~

~

230v50Hz

15v

+-

200A 200mA

35A = 35mA

35mA x 30E = 105v

DEDICATED GROUND

UTILITY GROUND

AUTO-GND SWITCH MANUAL-GND SWITCH

240240

PRIMARY TO CORE - 12kVPRIMARY TO SHIELD - 12kVSHIELD TO CORE - 12kVSECONDARY TO CORE - 50kV

DC ISOLATION XMER

[SEC COMPENSATEDFOR REGULATION]

+Vc -VcI

+Vc -VcI

+Vc -VcI

+Vc -VcI

A

B

A

BA

B

A

B

A

B

A B

A

B

A

B

A

B

SNUBBER

SNUBBER

FILAMENT

DCCT

DCCT

DCCT

DCCT

SHIELD

1 Ph 230V 50Hz

HVPS BIAS AND HEATING POWER SUPPLY INTERCONNECTION

14-08-2008 REV-1

STAR GROUND

60kV DC TRIAX

60kV DC TRIAX

60kV DC TRIAX

4-TURNS --gt 18v

PULSE CT - DRAIN

P-DRAIN-1

P-DRAIN-2

PULSE CT - ELEC

P-ELEC-1

P-ELEC-2

P-DRAIN-1P-DRAIN-2

I-DRAIN-1I-DRAIN-2

I-DRAIN-1I-DRAIN-2

OR

BUFFER

BUFFER

Iref

DRAIN-BREAK-TTL-DAC

PS-TRIP-TTL

DRAIN-OC-TTL-DAC

DRAIN-I-MONITOR-DAC

I-ELEC-1I-ELEC-2

V-HV-IN V-HV-OUT

V-ACC-IN V-ACC-OUT

V-HV-IN-1V-HV-IN-2

V-HV-OUT-1V-HV-OUT-2

V-ACC-IN-1V-ACC-IN-2

V-ACC-OUT-1V-ACC-OUT-2

I-ERD-MONITORTO DAC

P-ELEC-1P-ELEC-2

BUFFER

BUFFER

Iref

ELEC-BREAK-TTL-DAC

ELEC-OC-TTL-DAC

ELEC-I-MONITOR-DACI-ELEC-1I-ELEC-2

I-ION-1I-ION-2

PULSE CT - ION

P-ION-1

P-ION-2

P-ION-1P-ION-2

BUFFER

BUFFER

Iref

ION-BREAK-TTL-DAC

ION-OC-TTL-DAC

ION-I-MONITOR-DACI-ION-1I-ION-2

BUFFER

Vref

V-HV-IN-MONITOR-DACV-HV-IN-1V-HV-IN-2

V-HV-IN-OV-TTL-DAC

BUFFER

Vref

V-HV-OUT-MONITOR-DACV-HV-OUT-1V-HV-OUT-2

V-HV-OUT-OV-TTL-DAC

BUFFER

Vref

V-ACC-IN-MONITOR-DACV-ACC-IN-1V-ACC-IN-2

V-ACC-IN-OV-TTL-DAC

BUFFER

Vref

V-ACC-OUT-MONITOR-DACV-ACC-OUT-1V-ACC-OUT-2

V-ACC-OUT-OV-TTL-DAC

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1ASi4 25A

R4-2

R4-1

R2-1

1

CT5

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

Uf

230AC

R1-5R1-4

R3-5R3-4

R4-5R4-4

R5-5R5-4

TE1 TE2 TE3 TE4 TE5

1 2 3 4 5 6 7 8 9 1011 12

HEATING-3Cartridge-3

31 2 4 5 6 7 8 9 1011 12

31 2 4 5 6 7 8 9 1011 12

HEATING-2Cartridge-2

1 2 3 4 5 6 7 8 9 1011 12

2 3 4 5 6 7 8 9 10 11 12

Cartridge-1HEATING-1

R2-4R2-5

CT1

CT5

230AC

230AC

230AC

230AC

R1

R2

R3

R4

R5

R=Temperature Controler

West 66OO

WTO7O5OOdegc (Batman)WO23500degc (L6)

Part modified

LWL

R1-910

SiR 2A

EinNETWORK

20mA60V

033uF250V

Lemo A

Network module

Si6 2x 4ANETWORKEin

60V

033uF250V

20mA40V

40V

Cartridge-2HEATING-2HEATING-1

Cartridge-1PipeHEATING-5

BodyHEATING-4 HEATING-3

Cartridge-3

Si1 25A Si2 25A Si3 25A

R3-2

R3-1

R2-2

R1-1

R1-2

R5-2

R5-1

Si5 1A

R4-2

R4-1

R2-1

1

V

V

V

HEATING-4Body

HEATING-5Pipe

K1

CT4

CT1 CT2 CT3

CT2

CT3

CT4

230v50Hz

~A

B ~

Cs OVEN POWER SUPPLY

COIL 3COIL 2COIL 1

COIL 4COIL 5

GRIDHEATING

MONITORING AND INTERLOCK - HV PATH VOLTAGE amp CURRENT

Cs OVEN

V-MON-GB

I-MON-GB

V-SET-GB

V-SET-GB

24v DCPS+

-

24v

0v

~

~

230v50Hz 100k

1k

LED

AUXCONTACT

COM

STATUS

STATUS = 24V PS ON

STATUS = 0V PS OFFPFC

TTL

~ ~

TTL TO PFC

230v50Hz

PS ON0V - OFF24V - ON

A B

A

B

COIL 1COIL 2COIL 3COIL 4COIL 5

FROM Cs OVENPOWER SUPPLY

V-MON-GH

I-MON-GH

V-SET-GH

V-SET-GH

(TX) 5-CHANNEL (OVEN TEMPERATURE)

Figure 16 Detailed interconnection scheme

9 Summary Power supply system for the Negative ion source programme at IPR is discussed The system is divided among HV and heating amp Bias power supplies Various parameters of the HVPS along with the integration and measurement scheme have been discussed A typical breakdown grid breakdown detection scheme is presented along with the operational aspects of the HVPS Various parameters and operational procedures for the heating and bias power supplies are presented and a typical power supply interconnection scheme is shown for easy understanding Passive protection schemes and various design parameters are presented A detailed grounding and shielding scheme is proposed for the negative ion system at IPR is presented A complete interconnection scheme is presented and discussed which will aid in the error free connections and easy troubleshooting during the commissioning of the system

Acknowledgements The authors of this paper will like to acknowledge the extensive help and the discussions which the authors have had with Dr Peter Franzen Dr W Kraus Dr Staebler Mr Martens Christian Mr Frank Fackhart and Mr Thomas Franke during their training programs at IPP

10 References [1] Bansal G et al 2008 this conference [2] V Toigo E Gaio F Milani 2005 21st IEEENPS Symposium Sept2005 Page(s)1 - 4 [3] K Watanabe and M Mizuno S Nakajima T Iimura Y Miyai 1998 Review of scientific

instruments volume 69 number 1 [4] M Bigi V Toigo L Zanotto 2007 Fusion Engineering and Design 82 905ndash911

23rd National Symposium on Plasma Science amp Technology (PLASMA-2008) IOP PublishingJournal of Physics Conference Series 208 (2010) 012030 doi1010881742-65962081012030

12