3rd workshop on power converters for particle accelerators (pocpa) 2012 digital regulation by...

3rd Workshop on Power Converters for Particle Accelerators (POCPA)

2012

Digital Regulation by Emulating Analogue Controllers: Implementation

•The sound of power supplies

•Self-learning Regulation

Niels HeidbrookDESY

•Elimimate Supply voltage influence: Prefilter design


2012

AC load

Power supply

Iload

filter

C

LSCR bridge

12 pulseUSCR

f0=600Hz

ISCR ~ constant

U1

U2

U3


2012

Power supply

Iload

C

L

delay

U=4Vpp

f0=600Hz~

(Iload Delta-Sigma ADC delay = 1ms)

AC load


2012

filter

C

L

U=4Vpp

f0=600Hz

delay

~reaction ~

Iload

AC load


2012

Iload

filter

C

L

U=4Vpp

f0=600Hz

pre-delay

~pre-action ~U=4Vpp

f0=600Hz

action

AC load


2012

Iload

U=4Vpp

f0=600Hz~ ~

U=4Vpp

f0=600Hz

Power supply =

Frequency generator

600Hz @ 4Vpp => High internal filter current

AC load


2012

Self-learning Regulation

Power supply

Uload=D*UsupplyDUload

RegulatorDuty cycle D0

Usupply

Frequency generator

(Ram Curve)50Hz Mains triggerOnly hardware:

Iload

Iload

Iload = constant?change

D0


2012

Self-learning RegulationIload

USCR

f0=600Hz~ ~

Uout

f0=600HzPower supply =

Frequency generator

t

Uout

~

Ram curve

delay

Ram curve

Average Iload

Iload

pre-delay

50Hz Mains trigger

Only hardware:


2012

Self-learning RegulationIload

USCR

f0=600Hz~ ~

Uout

f0=600HzPower supply =

Frequency generator

t

Uout

~

Ram curve

delay

Ram curve

Average Iload

Iload

pre-delay

50Hz Mains trigger

Only hardware:

Instability at wrong learning delay

Too long Too short

Linear approximation between the points


2012


t

Uout

Ram curve

Average Iload

pre-delay

50Hz Mains trigger

Only hardware:


Solution 1:

Take less resolution of the Ram curve

Iload

Inaccurate at high frequencies

Linear approximation between the points


2012


t

Uout

Ram curve

Average Iload

pre-delay

50Hz Mains trigger

Only hardware:


Too long Too short

Mix in 1st derivation of Ram curve

Iload + K*d/dt(Ram curve)= constant

Iload is not constant

Solution 2:

Mix in 1st derivation of Ram curve


2012

Mains

=

~

Power supply

Rectifier

Load

Disturbance

Test circuit


Iload


2012

Power supply

Uload=D*UsupplyDUload

Regulator

Duty cycle D

Usupply

Elimimate Supply voltage influence:

Prefilter design


2012

Elimimate Supply voltage influence:

Prefilter design

Power supply

Uload=D1*UsupplyDPrefilter

D1=D/UsupplyUload

Regulator

Duty cycle D D1

Usupply

Prefilter

Uload=D1*Usupply

Uload=(D/Usupply)*Usupply

Uload=D


2012

The sound of power supplies


2012

The sound of power supplies

1. Unique WAV file Header

‘RIFF’

Size

(don’t care) ‘WAVE’ ‘fmt ’ Always: LSB is first


2012

The sound of power supplies1. Unique WAV file Header

Chunk size

(don’t care) Format code

Number of interleaved channels=1Sampling

Rate

22050Bit/s

Data Rate

44100Bit/s

Data block size

(don’t care)

Bits per sample=16

Speaker position mask

(don’t care)

First 16 bit data value

Size of extension

(don’t care)

Number of valid bits

(don’t care)

Hex:2078

Dez:8312

(complement on two)

=>invert MSB bit

Dez:8312=>

ADC value was 41080

Always: LSB is first


2012

The sound of power supplies2. Append test data (Saw tooth signal)

LSB

byte is always the same

(example)

MSB

byte counts downwards

2. Append ADC data in

2’s complement.

(inverted MSB bit)

Append LSB first.

1. Take the Header


2012

The sound of power supplies3. Wave analysis Audacity (freeware)

Mono, 22050 bit/s

WaveSawToothExample.wav

The data has to be long enough to be played in Winamp.


2012

The sound of power supplies4. Frequency analysis Audacity (freeware)1351Hz


2012

Java applet for continuous wave analysis

Digital regulation is needless

Have fun listening to your power supplies

Conclusion


2012

3rd workshop on power converters for particle accelerators (pocpa) 2012 digital regulation by...

Documents