3 modules 1.5 kW each3 modules 1.5 kW each• redundancy n+1• current sharing• interleaved operations

Switch In Line Converter - SILC• phase shift operation• ZVS transitions• high efficiency• reduced switch voltage stress • high frequency capability

Turn ratios Turn ratios 10:10:2: 10:10:2: 4 units connected in parallel4 units connected in parallel

Transient response

VVoutout

IIloadload

4.71

mm

22

laye

rs

10 layers2 concentric turnsin each layer

4 layers

4 layers

Planar transformerPlanar transformer

Q1

Q2

Q3

Q4T1

Co

C4 L

Vin

Vout

+

-C3

C2

C1

T2

T3

iT2

iL

T4

+

+

+

+

VVoutout = = 12V12V

13 cm13 cm

33 cm33 cm

7 cm7 cm

S1 S2

S3

S4

L1

Co RC1 L2

Uin Uo

+

-UC1

+

-

D<50% Uo = UinD/2Specifications:Specifications:Input voltage: Ug =

12 VOutput voltage: Uo =

2.5 VOutput current: Io = 3AOperating frequency: fs = 1

MHz

350 nH air core inductorsDimensions: L = 6cm, W =

4.2cm

Non-Isolated PoL ConverterNon-Isolated PoL ConverterInterleaved Buck with Voltage Divider - IBVDInterleaved Buck with Voltage Divider - IBVD

Characteristics:Characteristics:• Zero voltage switch turn on• High step-down ratio• Reduced switch voltage

stress (Uin/2)• Interleaved operation with

automatic current sharing and ripple cancellation

IBVDIBVD

Efficiency comparison (BEfficiency comparison (Bextext = 0) = 0)

Output current [A]Output current [A]

0.72

0.76

0.8

0.84

0.88

32.521.51

IBVDIBVD

Single BuckSingle Buck

Power Converters for Future LHC ExperimentsApollo collaboration, funded by I.N.F.N. Italy

M. Alderighi(1,6), M. Citterio(1,*), S. Latorre(1), M. Riva(1,8), M. Bernardoni(3,10), P. Cova (3,10), N. Delmonte(3,10), A. Lanza(3), R. Menozzi(10), A. Costabeber(2,9), A. Paccagnella (2,9), P. Tenti(2,9), F. Sichirollo(2,9), G. Spiazzi(2,9), M. Stellini(2,9), S. Baccaro(4,5), F. Iannuzzo(4,7), A. Sanseverino(4,7), G. Busatto(7), V. De Luca(7)

(1) INFN Milano, (2) INFN Padova, (3) INFN Pavia, (4) INFN Roma, (5) ENEA UTTMAT, (6) INAF, (7) University of Cassino, (8) Università degli Studi di Milano, (9)

University of Padova, (10) University of Parma,

Main converter Main converter

Efficiency (Bext = 0)

Output power [kW]Output power [kW]0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

0.5

0.6

0.7

0.8

0.9

1

Main converter module thermal design3D Finite Element Model (FEM)•FE modeling of the main heating components:

• Input power MOSFETs• Output diodes• Inductor• Planar transformer

Thermal measurements 1•Thermal characterization on single components, to validate models

•Thermal design•Designed advanced solutions to improve heat exchange:

• Power MOSFETs mounted on IMS board• ISOTOP diode isolated package directly mounted on baseplate• Copper thermal layers for transformer core cooling • Silicone gap filler for transformer windings cooling

Thermal simulation and measurements 2•Preliminary thermal measurements on the air cooled whole converter

Final requirements• Main converter output power = 3x1 kW• Case dimensions: 150 x 402 x 285 mm3

• Max case temperature = 18°C• Water cooling system

• delivery = 1.9 l/min• p = 350 mbar• Tinlet = 18°C• Toutlet ≤ 25°C

Measurement pointΔTSIM [°C]

ΔTMIS [°C]

ε [%]

Transformer core 55 51 8Primariy windings 67 73 8Secondary windings 75 70 7ISOTOP diodes 47 49 4Inductor 23 24 4

Proposed Power Supply Distribution System Proposed Power Supply Distribution System

Characteristics:Characteristics:• Main isolated converter with N+1 redundancy• High DC bus voltage (12V or other)• Distributed Non-Isolated Point of Load

Converters (niPOL) with high step-down ratio

CRATE

280 Vdc

Main DC/DC

Converter

Card #3

POLLDO Converter

POLLDO Converter

POLLDO Converter

IBConverter

IBConverter

Card #2

POLLDO Converter

POLLDO Converter

POLLDO Converter

Card #1

POLniPOL Converter

POLniPOL Converter

POLniPOL Converter

48Vdc10%Regulated DC busRegulated DC bus

ni Regulated ni Regulated Power ConvertersPower Converters

Intermediate DC bus

12V10%5V10%

CRATE

280 Vdc

MainDC/DC

Converter

Card #3

POLLDO Converter

POLLDO Converter

POLLDO Converter

Card #2

POLLDO Converter

POLLDO Converter

POLLDO Converter

Card #1

POLniPOL Converter

POLniPOL Converter

POLniPOL Converter

Regulated C busRegulated C bus

POL Converter with high step-down ratio

The increase of the radiation background and the requirements of new front-end electronics will characterize the future LHC luminosity upgrade and are incompatible with the current capability of the distribution systems in use. An isolated dc-dc resonant main converter (MC) and Point of Load (POL) converters deployed at the very heart of the experimental setup have been proposed to face these new requirements. The MC, with redundancy characteristic, supplies an intermediate “medium” voltage bus which distributes the voltage to the electronic front-end and read-out boards, where non-isolated Point of Load converters are implemented for precise voltage adaptation and regulation.In Large Hadrons Collider applications the design of these electronics equipments, which must cope with a highly hostile environment in terms of high radiation and a background magnetic field up to 2 Tesla, opens a severe tolerance issue for the integration technology.

Test case: ATLAS Liquid Argon (LAr) CalorimetersATLAS Liquid Argon (LAr) Calorimeters

orange = primary winding voltage blue      = secondary winding voltagemagenta  = primary winding currentgreen = snubber current (proportional to the switching losses).

Bstat. 789 Gauss Bstat. 2591 Gauss

Specific activities are addressed to obtain a ferromagnetic nucleus able to produce high magnetic field with limited current stimulations. The base elements consist in a mixture of Fe and Si powders blended in precise ratio (percentage of organic additives, and blending methodology are key points) in order to make a ferromagnetic compound injection moulded in test sample.

VDC

vc

DRIVER

DUT

L

VCC+

C1

iDUT

Rshunt

+

EPC GaN MOSFET

X-rays for checking the solder quality

Turn on interval @ Vcc = 100V, IDS = 0A

Rshunt = 85 mUGS [1V/div]

UDS [20V/div]

-IDS [1A/div]

Time [10ns/div]

Turn off interval @ Vcc = 100V, IDS = 5A

UGS [1V/div]UDS [20V/div]

-IDS [1A/div]

-poff(t) Time [10ns/div]

Measured DUT voltage and current during switching intervals

101

102

103

104

105

-20

-10

0

10

20

30

40

Mag

nitu

de [d

B]

101

102

103

104

105

-200

-150

-100

-50

0

50

Frequency [Hz]

Pha

se [d

eg]

@350 W@400 W@450 W

Output voltage responseto a load step change

(25 A 37 A)

Small signal dynamics

Transformer behavior in stationary Magnetic Field

48V5%12V5%

Air bubbles

(*) Presenter