agostino lanza, on behalf of the apollo collaboration

The APOLLO Project: LV Power Supplies For The Next High Energy

Physics Experiments

Milano, October 19, 2011

Agostino Lanza, on behalf of the APOLLO CollaborationM. Alderighi(1,6), M. Citterio(1), M. Riva(1,8), P. Cova (3,10), N. Delmonte(3,10), A.

Lanza(3), R. Menozzi(10), A. Paccagnella (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) University of Milano, (9)

University of Padova, (10) University of Parma

http://www.unipd.it/index.htm

http://www.mi.infn.it/indexIT.shtml

Features of the PS systems required by the present experiments (mainly at LHC)

Milano, October 19 2011 The APOLLO Project - Agostino Lanza

2

Extensive use of the DC/DC technology, which requires a careful design in terms of EMC

Integration with detectors at the design level, to avoid both mechanical and electrical criticalities

Necessity of rad-hard devices, so to place modules in the experimental caverns

Necessity of B-tolerant systems, to be able to place them close to detectors

Implementation of redundancy, because of difficult access of no access at all

Very complex DCS systems, in order to get a fully remote control

Industrial engineering design and industrial scale production

Requirements of future LHC upgrades and new experiments


3

New design, full replacing the present systems whose design dates from early 2000 years

Increased rad-hard performance, because of the increased luminosity of accelerators

Minimization of power loss in cables used for carrying current from PS distributors to the front-end of detectors, moving distributors as close as possible to the front-end

Increased B-tolerance of systems getting closer to detectors and magnets

Better reliability and controls, in order to reduce access time and increase the overall detector efficiency

Avoiding industrial intellectual property, trying to implement the CERN Open Hardware policy

The APOLLO proposal – System architectures


4

Case study: ATLAS LAr calorimeters

CRATE

280 Vdc

Main DC/DC

Converter

Card #3POL

LDO Convert

er

POL

LDO Convert

er

POL

LDO Convert

er

Card #2POL

LDO Convert

er

POL

LDO Convert

er

POL

LDO Convert

er

Card #1POLniPOL

Converter

POLniPOL Converter

POLniPOL ConverterRegulated

DC bus

POL Converter with high step-down ratio

Characteristics:• Main isolated

converter with N+1 redundancy

• High DC bus voltage (12V or more)• Distributed Non-

Isolated Point of Load Converters (niPOL) with high step-down ratio

The APOLLO proposal – System architectures


5

Parallel study: ATLAS Muon detectors

MuonDetectors

280 Vdc

Main DC/DC

Converter

Chamb #3POL

LDO Convert

er

POL

LDO Convert

er

POL

LDO Convert

er

Chamb #2

POL

LDO Convert

er

POL

LDO Convert

er

POL

LDO Convert

er

Chamb #1

niPOL Converter

Regulated DC bus

POL Converter with high step-down ratio

Characteristics:• Main isolated

converter with N+1 redundancy

• High DC bus voltage (12V or more)

• Distributed Non-Isolated Point of Load Converters (niPOL) with high step-down ratio, on-chamber installed and high B-tolerant

The APOLLO proposal - Topologies


6

Q1

Q2

Q3

Q4

T1

Co

C4 L

Vin

Vout

+-C3

C2

C1 T2

T3

iT2

iL

T4

+

+

+

+

Vout = 12V

The Main DC/DC Converter3 modules 1.5 kW each• redundancy n+1• current sharing• interleaved operationsSwitch In Line Converter - SILC• phase shift operation• ZVS transitions• high efficiency• reduced switch voltage stress • high frequency capability

13 cm

33 cm

7 cm

Efficiency (Bext =

0)

Output power kW]0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.60.5

0.60.70.80.9

1 Transient response

Vout

Iload

Output voltage responseto a load step change (25 A 37 A)

The APOLLO proposal – Thermal sizing


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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

3D 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

The APOLLO proposal - Topologies


8

The Point of LoadsS1 S2

S3

S4

L1

Co RC1 L2

Uin Uo

+

-UC1

+-

D<50% Uo = UinD/2

Interleaved Buck with Voltage Divider – IBVD

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

Co

C1

Cin

L1L2

S1

S3

S4

Specifications:Input voltage: Ug = 12 VOutput voltage: Uo = 2.5 VOutput current: Io = 3AOp. frequency: fs = 1 MHz

350 nH air core inductorsDim.: L = 6cm, W = 4.2cm

Specifications:Input voltage: Ug = 12 VOutput voltage: Uo = 2 VOutput current: Io = 20AOp. frequency: fs = 280 kHz

2.2 mH ferrite core inductorsDim.: L = 7cm, W = 3.5cm

The APOLLO proposal – Rad-hard devices


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Seeking for power MOSFETs radiation tolerant up to 10kGy and 1014/(s ∙ cm2) neutrons and protons: many components, with Vd ranging from 30V to 200V and polarized in

various configurations, were tested at the 60Co g ray source in the ENEA center of Casaccia, near Roma

same components were tested with a heavy ion beam, 75Br at 155MeV, at INFN Laboratori Nazionali del Sud in Catania

within the end of the year same components will be tested under neutrons, at the Casaccia nuclear reactor Tapiro, and under protons, at INFN LNS

Seeking for power MOSFETs, controllers and FPGA radiation tolerant:

first irradiation was performed under 216MeV proton beam in Boston, at Massachusetts General Hospital facility, using some of devices irradiated in Italy. Other irradiation campaigns are planned at the same facilities in the next months

Results are still preliminary and under analysis. Other irradiation campaigns are necessary in order to select good devices

The APOLLO proposal – Rad-hard devices


10

Some preliminary results of g irradiation up to 9600 Gy of the 200V MOSFET IRF630

The APOLLO proposal – New technologies


11

VDC

vc

DRIVER

DUT

L

VCC+ C1

iDUT

Rshunt

+

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

UGS [1V/div]

-IDS [1A/div]

Time [10ns/div]

Rshunt = 85 mW

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

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

-IDS [1A/div]

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

Study of EPC GaNs:

Work in progress since early 2011 Two device types under test: 40V and 200V Difficulties found for soldering devices on PCB Electrical characterization in progress Rad-hard tests will come soon

Measured voltage and current during switching periods of a GaN device

GaN test circuit

The APOLLO proposal – New technologies


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Study of high-B materials: Collaboration with the private company FN

S.p.A. Base material by Hoganas, FES168 HQ, Fe –

Si(6.5-6.9%) Problems found and solved in the injection

moulding phase Still problems in the sintherization phase First B tests by end of the year (hopefully)

First moulded samples of FES168

Collaboration with a CERN group (F. Faccio). It aims at studying current sharing of already existing integrated DC/DC converters with low output currents (< 3A), designed by that group

agostino lanza, on behalf of the apollo collaboration

Documents

apollo collaborationm

infn milano

university of milano

redundancy high dc bus

present systems

ps systems

main isolated converter

careful design