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Design and Development of a Low Cost, Manufacturable High Voltage Power Module for Energy Storage SystemsDOE Phase II SBIREESAT Sept. 24, 2015

Chad B. O’NealSenior Staff Engineer

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Motivation

ObjectiveDevelop a high voltage (> 15kV) silicon carbide (SiC) power module to aid in the emergence of smarter, seamless powered grids.

Applications• Energy storage systems• Solid-state transformers• Naval power distribution• Electric locomotives• Medium voltage drives• Solid-state circuit breakers

0

500

1000

1500

2000

Max

imum

Pow

er (k

W)

88%90%92%94%96%98%

100%

1 kHz 15 kHz

Effic

ienc

y

Switching Frequency (Hz)

> 25x

8%

Wide bandgap enables higher efficiency and power density

6.5 kV 200 A Si IGBT 10 kV 50 A SiC MOSFET 15 kV 100 A SiC IGBT

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Advantages• Reduce

size/complexity of multi-level systems

• Eliminate cooling systems

• Increase efficiency and power density

Motivation – Reduce System Complexity, Reduce Cost

-2

2

6

10

14

18

22

26

0

2

4

6

8

10

12

14

0 10 20 30 40

Num

ber o

f Sw

itche

s

Num

ber o

f Lev

els

System Bus Voltage (kV)

6.5 kV Si IGBT

12 kV SiC MOSFET

~ ½ Components- Modules- Gate Drivers- Passive

components- System housing

materials

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Power Electronics and Energy Storage Market

SiC Power Electronics Market• < 600 V - Strong Competition

With Si and GaN• > 1.2 kV – Ideal Area for SiC;

Apps are less cost driven and performance improvement is obvious 2012

Energy Storage Market• The global energy storage market is expected to grow from

$39.7B in 2011 to $61.9B by 2016 at an annual growth rate of 9.3% [1]

[1]. http://www.marketresearch.com/MarketsandMarkets-v3719/Advanced-Energy-Storage-Technologies-Type-6671586/

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Market Segmentation in Power Electronics by Application and Voltage

[2]. Yole Developpement, 2014.

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Develop HV packaging approach and demonstrate it via hardware testing

Design HV SiC MCPM based on hardware demonstrator

Build and perform electrical, thermal, and reliability testing for the HV SiC half-bridge MCPMProgram

Start

APEI, Inc. will work with its partners to transition this HV MCPM technology to a commercial product

Key Deliverables:Discrete HV hardware demonstrator and MCPM design

Phase I Phase II Phase III

Key Deliverables:High Performance HV Half-bridge SiC MCPMs

Assembly process transition and manufacturing process yield optimization,

Fully qualify HV SiC MCPM

Project Plan

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Design Features of XHV-3-V

+V

MidpointHigh Temp. Lid

Creepage Extenders

210 mm × 102 mm × 32 mm

Advantages of SiC Devices• High breakdown voltage• High thermal conductivity• High switching frequency• High temperature operation

Power Module Features• SiC MOSFETs or SiC IGBTs

• Low profile• Reduced volume/weight• High temperature capable• Reworkable

SiC IGBT MCPM 15 kV 80 A

SiC MOSFET MCPM 10 kV 60 A

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Thermal Modeling Results

0

50

100

150

200

250

800 1200 1600 2000

Tj (°

C)

Dissipated Power (W)

Forced Air (.05 C/W)Cold Plate (.01 C/W)

Rjc < 0.06 °C/W(per switch position)

Pd = 2000 W

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25

75

125

175

225

-0.5 1.5 3.5 5.5 7.5

Tem

pera

ture

(°C)

Z Position (mm)

Liquid Cooled (0.01 °C/W)

2.0 kW 1.6 kW

1.2 kW 0.8 kW

Thermal Simulations

Thick dielectric necessary for voltage isolation hindersthermal performance

The change in temperature through the thickness of the power module stack-up for a (top) fan-cooled heat sink and (bottom) liquid cold plate.

25

75

125

175

225

-0.5 1.5 3.5 5.5 7.5

Tem

pera

ture

(°C)

Z Position (mm)

Air Cooled (0.05 °C/W)

2.0 kW 1.6 kW

1.2 kW 0.8 kW

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Parasitic Simulations

0

10

20

30

40

50

60

1.E+3 1.E+4 1.E+5 1.E+6 1.E+7

Indu

ctan

ce (n

H)

Frequency (Hz)

mid-drain loopmid-source loop

10 kHz

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Static Testing

0.E+00

5.E-06

1.E-05

2.E-05

2.E-05

0 2 4 6 8 10

I DS

(A)

VDS (kV)

Top Switch

Bottom Switch

0.E+00

5.E-10

1.E-09

2.E-09

2.E-09

0 5 10 15 20 25

I GS

(A)

VGS (V)

Top SwitchBottom Switch

0

0.1

0.2

0.3

0.4

0.5

0 10 20 30 40 50

RD

SON

(Ω)

IDS (A)

Top SwitchBottom SwitchFour 10 kV / 10 A SiC

MOSFETs and Four 10 kV / 10 A Schottky Diodes Per Switch Position

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• Tested BV and leakage of a fully assembled/potted module as a function of temperature

• Isolation test = All connections were shorted and the baseplate was connected to low

• The leakage was less than 0.2 µA at 150 °C.

• This is orders of magnitude lower than the device leakage at temperature

High Voltage, High Temperature Static Isolation Tests

0.E+00

2.E-07

4.E-07

6.E-07

8.E-07

1.E-06

0 5 10 15 20 25

I DS

(A)

VDS (kV)

25 °C 125 °C 150 °C

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Double Pulse Test Setup Utilizing a Clamped Inductive Load (CIL)• Two controlled pulses turn DUT on and off• Inductive load facilitates control of current

through the DUT• Allows for measurement of turn-on and turn-

off switching losses at desired drain-to-source voltages and currents

• Gate Drive Circuit– 10 kV Isolation, 10 kV DC rail capable – Controllable gate output rails (Set at +20V / -5V)– Gate resistor was varied to control speed of

switch: 2.5 Ω, 10 Ω, and 20 Ω• Safety

– Test Setup has multiple mechanical fail safes– Test Setup is completely controlled via wireless

communication

Dynamic Testing

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• Rg=2.5 Ohms, I_test = 28 A • Voltage fall time (turn-on) has increased but not in the same amount• Voltage Rise time (turn-off) has reduced to 100ns during turn off

Switch Curves of Submodule

102 ns (78 kV/µs) 72 ns (111 kV/µs)

10× Faster than Si IGBTs

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• Total switching losses for a commercial Si 6.5 kV / 250 A module are ~ 2.6 J [3]• This higher power density SiC Module has over an order of magnitude lower losses

Switching Losses vs. Current at 8 kV

0

50

100

150

200

250

300

350

10 20 30 40 50

Ener

gy (m

J)

Current (A)

Module Switching Energy

Turn On (Rg=10Ω) Turn On (Rg=20Ω)Turn Off (Rg=10Ω) Turn Off (Rg=20Ω)Total (Rg=10Ω) Total (Rg=20Ω)

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30

Ener

gy (m

J)Current (A)

Submodule Switching Energy

Turn On (Rg=2.5Ω) Turn on (Rg=10Ω)Turn Off (2.5Ω) Turn Off (Rg=10Ω)Total (Rg=2.5Ω) Total (Rg=10Ω)

[3]. FZ250R65KE3 datasheet.

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We would like to thank Dr. Imre Gyuk of the DOE Energy Storage Systems Program and Dr. Stan Atcitty for his technical contributions.

Acknowledgements

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

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