high power density silicon carbide power electronic converters · marcelo schupbach, ph.d. chief...
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Energy Storage Systems Program1
DOE Energy Storage & Power Electronics Research ProgramsSeptember 29 −
30, 2008
Marcelo Schupbach, Ph.D.Chief Technical Officer
APEI, Inc.535 Research Center Blvd.Fayetteville, AR 72701
Phone: (479)-443-5759
Email: [email protected]: www.apei.net
High Power Density Silicon Carbide Power Electronic Converters
Funded by the Energy Storage Systems Program of the U.S. Department Of Energy (DOE/ESS) through the Small Business Innovation Research (SBIR) program and managed by Sandia National Laboratories (SNL). Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration, under contract DE-AC04-94AL85000
Energy Storage Systems Program2
Overview
• Broader Impact of SiC-based Power Converter• Development of 10-kVA SiC Inverter
– APEI’s
Goals– SiC Power Devices Selection and Characterization– Testing of 10-kVA All SiC Inverter Prototype
• Summary
Energy Storage Systems Program3
Theoretical Electrical Advantages
Very high voltage blocking
Very low switching losses (up to 1/10th of Silicon)
Low on-resistance
Up to 10s of GHz switching range
Theoretical Thermal Advantages
SiC device theoretical limit exceeds 600 °CVery high power densities can be achieved
with these junction temperatures
SiC has a very high thermal conductivity— excellent for power devices and thermal transfer, increases power density
Disadvantage:
No device packaging technology exists to take full advantage of thermal capabilitiesRequires packaging advances in die attach, interconnects, and reliability
Advantages of Silicon Carbide (SiC)
Conceptual View
SiC Power ModuleStandard Power Module
Energy Storage Systems Program4
DOE ESS Phase II SBIR (FY06)• Phase II started on August 2006 • Goals of Phase II:
1.
Develop a higher power SiC-based fully-functional multi-purpose inverter2.
Improved efficiency (>96%) 3.
Large weight and volume reduction 4.
Similar functionality
• Ratings of Phase II Prototype – Power: 10 kVA– VDC from 350V to 700 V– Efficiency > 96%– Ambient Temperature > 75 °C– Weight << 100 lbs– Volume << 2.5 cubic foot– Other Important parameters:
• Maximum AC current ~ 31 Arms• AC output current THD < 5 %• Maximum DC current ~32 A
Energy Storage Systems Program5
SiC Devices Presently “Available”SiC Diodes
Several commercial products available
Schottky
diodes from Cree, Inc. and Infineon (SiCED)
300V, 600V and 1200V
20+A and recently 50+A single die
SiC Controllable Switches
Normally-off: VJFETs
(Lower Voltage), BJTs, MOSFETs
and Thyristors
Normally-on: VJFETs
(also MESFETs
and SIT)
SiC normally-on VJFETs
is one of the most mature
1200V and 1600V 50+A per die (SiCED)
600V and 1200V up to 20A per die (Microsemi)
SiC SuperJFET, 1200V/50 die (GeneSiC)
SiC BJTs
1200V up to 20A per die (TranSiC, also Cree)
SiC MOSFETs
600V,900V and 1200V up to 30A
(Cree, Northrop Grumman, Rohm)
Energy Storage Systems Program6
Characterization of SiC DevicesTurn Off Waveforms
Current
Voltage
PowerEoff= 20µJ
0
250
500
0
50
100
150
200
250
0 1 2 3 4 5 6 7 Voltage (V)
Switching Loss (uJ)
Current (A)
0‐50 50‐100 100‐150 150‐200 200‐250
Switching Loss Map
‐0.100
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0 100 200 300 400
On‐Re
sistance (Ohm
s)
Temperature (°C)
On‐Resistance with VGS = 0V
ID, min
ID = 15A
ID = 30A
0
0.5
1
1.5
2
2.5
3
‐24
‐23.5
‐23
‐22.5
‐22
‐21.5
‐21
‐20.5
0 50 100 150 200 250 300 350
Forw
ard Conduction Voltage (V)
Avalanche Breakdown Voltage (V
)
Temperature (°C)
Energy Storage Systems Program
10-kVA Three-Phase Inverter Prototypes
7
Output Filter
DSPTMS320F2811
Output Filter* Three modules were used
Silicon System
Silicon Carbide System
Gate Drivers
Energy Storage Systems Program
Comparison of Used Si and SiC Devices
8
Si IGBT
SiC JFE
T
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5
Drain Current (A
)
Drain‐Source Voltage (V)
VGS = 0V VGS = ‐2V VGS = ‐4VVGS = ‐6V VGS = ‐8V VGS = ‐10VVGS = ‐12V VGS = ‐14V VGS = ‐16VVGS = ‐18V VGS = ‐20V
0
10
20
30
40
50
60
70
80
90
100
0.0 1.0 2.0 3.0 4.0 5.0
Drain Current (A
)
Drain‐Source Voltage (V)
VGS = 0V VGS = ‐2V VGS = ‐4VVGS = ‐6V VGS = ‐8V VGS = ‐10VVGS = ‐12V VGS = ‐14V VGS = ‐16VVGS = ‐18V VGS = ‐20V VGS = 0V
25 °C 125 °C
25 °C 150 °C
SiC JFE
T
Device Area
Energy Storage Systems Program9
Characterization of SiC InverterEfficiency Measurements on SiC Inverter
Variable Resistive Load
Various LC Output Filters were used
Several Switching Frequencies: 8 kHz, 10 kHz and 20 k Hz
PWM Generation: Sine Triangular and Space Vector
Multiple DC Bus Voltages From 450 VDC to 600 VDC
Measurements were taken under constant ma.
Load Currents Load Voltages
DC Input Voltage
Energy Storage Systems Program10
Efficiency Characterization
90
91
92
93
94
95
96
97
98
99
100
0 2 4 6 8 10 12 14
Efficency
Power (kW)
Si IGBT, Fsw=10kHz
VDC = 600 VDCma = 95%
90
91
92
93
94
95
96
97
98
99
100
0 2 4 6 8 10 12 14
Efficency
Power (kW)
Si IGBT, Fsw=10kHz
SiC, Fsw=10kHz
SiC, Fsw=20kHz
VDC = 600 VDCma = 95%
90
91
92
93
94
95
96
97
98
99
100
0 2 4 6 8 10 12 14
Efficency
Power (kW)
Si IGBT, Fsw=10kHz
SiC, Fsw=10kHz
SiC, Fsw=20kHz
SiC, SV, Fsw=8.5kHz
SiC, Fsw=10kHz, No Filter
VDC = 600 VDCma = 95%
CEC = 98.3%EE = 98.1%
Energy Storage Systems Program11
Potential For Size Optimization
Energy Storage Systems Program12
Potential For Size Optimization
02000
40006000
800010000
0
100
200
3000
50
100
150
200
Output Power (W)Juntion Temperature (oC)
Tota
l Los
s (W
)
02000
40006000
800010000
0
100
200
3000
50
100
150
200
250
Output Power (W)Juntion Temperature (oC)
Tota
l Los
s (W
)
Fsw
= 10 kHz Fsw
= 30 kHz
Heatsink: 133 C
Die 1: 255 C
Die 2: 258 C
210 C
DBC Substrate: 155 C
Power Loss = 300 Watts
Energy Storage Systems Program13
Potential Size Reduction10-kVA SiC VJFET Inverter
Estimated CEC Efficiency = 96% Junction Temperature = 300 °CSwitching Frequency = 30 kHzEstimated Power Loss = 230 WHeatsink Dimension = 7”x5”x1”
Volume = 35 in3 (~ 10x reduction)
10-kVA Si IGBT InverterEstimated CEC Efficiency = 96%Junction Temperature = 100 °C Switching Frequency = 10 kHzEstimated Power Loss = 230 WHeatsink Dimension = 18”x7”x3”
Volume = 378 in3
10 kHZ
LC Filter Dimensions: 5.75”x8”x5”
Volume: 230 in3
30 kHZ
LC Filter Dimensions: 5”x5”x3”
Volume: ~ 75 in3 (~ 3x reduction)
1”
7”5”
1”
7”5”
Energy Storage Systems Program14
Summary
Goal of Phase II work – Develop a 10-kVA all-SiC three-phase inverter – System efficiency (>96%)– Weight and volume minimization options
Contributions of Phase II work up to this point– Design, fabrication, testing and characterization of
10-kVA all SiC Inverter• Selection and full characterization of used SiC devices (i.e.,
static and dynamic characterization vs. temperature, statistical dispersion)
• Paralleling of multiple SiC devices• Developed high temperature (300+ °C) SiC device packaging
technology (i.e., wire bonds, die attach, substrate and encapsulation)
• Developed of gate driver circuitry
Energy Storage Systems Program15
Summary
Contributions of Phase II work up to this point (Cont.)– Demonstration of high efficiency operation:
• Multiple output filters and PWM modulation schemes were compared.
• Performance comparison to “equivalent”
Si system• Measured SiC system showed an ECE = 98.3% and EE = 98.1%
– Demonstration that important weight and volume minimization
are possible (tradeoff studies)
Future work– SiC system characterization while operating at high junction
temperature (250+ °C)
Energy Storage Systems Program16
Summary
SiC device technology has the potential of greatly increase the performance of power converters– Higher efficiency– Smaller size– Higher reliability– And ultimate lower cost
Where do we go from here?– Higher voltage and higher power applications
• Power capability of single-chip devices – Advances in key components– Reliable packaging technologies– SiC Cost
Energy Storage Systems Program17
Acknowledgments
• Department of Energy (DOE) – Energy Storage System Program, directed by
Dr. Imre Gyuk– Sandia National Laboratories, Dr. Stan Atcitty
• APEI’s
Partners– GeneSiC– State of Arkansas– Northrop Grumman Advanced Technology Center