IPT Electronics : High Power Density Inverter

„ 65kW at 250V (80kW at 300V)

„ 500ARMS at 57C coolant, 450ARMS at 72C coolant

„ 22kg => 3000W/kg (includes 3/2kW bidirectional DC-DC converter)

„ Advanced power control circuits

„ High accuracy torque control

DC-DC Converter Traction „ Designed for Section Inverter automotive reliability Section INVERTER R&D System Simulation Framework – E-Drives

Customer Specification

Matlab/Simulink Controller Transmission Assumptions V DC V AC M M M T DC Supply Transmission Load IDC Inverter IAC Motor N M N T

Motor Requirements Motor Electromagnetic Design Ansoft/Speed

Performance Evaluation Motor Mechanical Design DyRoBeS

Motor Thermal Design MotorCad/Ansoft Inverter Requirements

Preliminary Design Matlab Transmission Requirements Preliminary Design Cost Evaluation

INVERTER R&D Advanced Technology Developments

Power Semiconductor Packaging Design & Manufacturing

INVERTER R&D ECOSTAR POWER MODULE FACILITY

In t s e l t rc ia n o t e n a m n p e e S ir c u t q io e n R Silicon Efficiency

s R & h e l t l a a ia P b rm e il e c it h n y T ta c u d In

• Thermal Stress on wire bonds

• Inductive effects in Power Module

INVERTER R&D Thermal and Mechanical Properties of Each Layers

Material Density Thermal condutivity Specific heat Young’s modile CTE (kg3 m ) (W/m K) (J/kg K) (GPa) (ppm/K) Copper 8979 389 381 112.9 16.4 AlSiC 3100 150 880 227 6.8 60Sn/ 40 Pb solder 8470 50 364.5 29.8 21.1 DBC AIN 8930 170 431 327 2.5 95Pb/ 5Sn solder 11100 35 133.7 20.4 25.1 Thermal grease 2703 0.735 796 0.011 16.4 Aluminum 2760 237 858.8 70 23.6 Silicon 2330 153 @ 25 oC 702 112.9 2.54 119 @ 77 oC 98.9 @ 127 oC 76.2 @ 227 oC

INVERTER R&D Thermal Resistance Predicted Using Numerical Tools

„ In developing Ballard Custom Power Module with integrated pinfin baseplate, computational fluid dynamics (CFD) was used to simulate fluid flow along fins and heat transfer within solids. CAD model „ The predicted maximum junction-to-coolant thermal resistance is 0.09 oC/W per switch, and the average number is about 0.08 oC/W per switch.

Temperature predicted from CFD simulation

INVERTER R&D Junction Temperature of IGBT and Diode

118.2 „ Application condition similar to 114.9 111.6

IPT “Full Torque Stall”. 108.2 „ Power loss is 350W for IGBT and 104.9 105W for Diode per switch. 101.6 98.3

o 95.0 „ Coolant inlet temperature is 85 C, Inlet flow rate is 2 gpm. 91.6 88.3 Outl et 85.0 Temperature predicted from CFD simulation for CPM with pinfin baseplate

IGBT and Diode Temperature for CPMs with Flat and Pinfin Baseplates CPM wi th f l at A lSi C baseplate CPM wi th pinf i n A lSi C baseplate

o T(jIGBT C) 139 118

o T(jDiode C) 127 112

INVERTER R&D Comparison

„ Thermal resistance reduced by 40% for integrated pin-fin power module.

Standard flat Integrated pin-fin Percentage baseplate baseplate reduction

Average thermal 0.12 oC/W 0.07 oC/W 40% resistance per swi tch

Average IGBT 97 oC 81oC 40% * junct i on temperature

Maxi mum measured 105 oC 84oC 47% * IGBT temperature * Note: Percentage reducti on refers to temperature difference between junction and coolant that has inl et temperature of 60 oC in th i s test.

INVERTER R&D Problem Approach to Inductance Challenge

1.00 Simulation & Modeling of Structure

2.00 Inductance formulae for current paths

3.00 Physical Systems Test

INVERTER R&D Inductance Analysis

OBJECTIVES

• Optimize layout for minimum inductance • Reduce Parasitics • Lower switching losses • Minimize effects of body diode recovery • Reduce bond wire stress • Minimize EMI

„ Alternative Embedded Busbar Structures

INVERTER R&D „Inductance Analysis of the D.C. Link

ANSOFT Simulation Model

Measured Results Units = nH Termi na ls shorted Ta Tb Tc phase Sa 4.5 7.2 9.2 Sb 6.0 4.1 6.0 Sc 9.2 7.2 4.5

INVERTER R&D Path Inductance - The Bond Wires

Delta Inductance - 15 mil & 20 mil Path Inductance of Bond Wires Wires 1.2 1 1 0.8 0.8 0.6 0.6 20mil nH nH 15 mil 0.4 0.4

Inductance in nH 0.2 0.2 0 0 0 1020 30 Wire #'s - (1-2), (2-3), (3-4) Wire Diameter in mil

Physical Testing Formulae Based 15 mil wire

INVERTER R&D Achieved Benefits

„ Increased package performance:  Significant reduction in parasitic inductance  Significant reduction in thermal resistance  Increased power density „ Increase packaging integration „ Reduced system packaging space „ Reduced system cost „ Improved reliability

INVERTER R&D 1.00 E +00 Transient Thermals ° C/W 1.00 E-01 Cu Junction to Base Comparison Cu Substrate to Base - Al203 Cu baseplate 1.00 E-02 AlSic : Junction to Base With Al203 DBC AlSic : Substrate to Base - AlN compared to

AlSic and Aln 1.00 E-03 DBC.

AlSic & Aln offers a 10% improvement 1.00 E-04 in thermal resistance Due to the Aln DBC substrate

1.00 E-05 1.00 E-05 1.00 E-04 1.00 E-03 1.00 E-02 1.00 E-01 1.00 E+00 1.00 E+01

100mS - Pulse - 800A Power Module INVERTER R&D Materials Reliability

1.00 E +08 Comparison Wire Bond Capabili ty with coati ng 1.00 E+07 • Cu with Al203 Wire Bond Capabili ty with NO protecti ve coat ing

1.00 E+06 • AlSic with Aln

• Wire Bond Coating improvement 1.00 E+05

Solder fati gue for A lSi c & A ln

1.00 E-04

Solder fati gue for Cu & Al 203

1.00 E-03 110 130 150 30 50 70 90

Temperature Delta in Tj

INVERTER R&D POWER SILICON

• IGBT Heat Diffusion

• Stress in bond wire.

- IGBT Devices evaluated - Eupec, Semikron, ABB, Toshiba, Hitachi, Fuji

This view is below bond wire.

INVERTER R&D TOSHIBA IGBT Technical Trend for Cross Section (600V – 1700V)

ConventionalConventional Design Design CurrentCurrent Design Design FutureFuture Design Design

PT-Trench Thin NPT-Trench Ultra Thin PT-Trench Emitter Gate Emitter Gate Emitter Gate P+ P+ P+ P- Base P- Base P- Base N+ N+ N+ N­ N- (Epi) N Buffer N­ N Buffer P+ P+ Collector P+

Collector

• Ultra Thin Wafer ImprovementImprovement for for TradeTrade off off of of • Low Injection Efficiency Eoff-VCE(sat)Eoff-VCE(sat)

Collector INVERTER R&D TOSHIBA

600V IGBT Eoff-VCE(sat) Trade-off Ultra Thin PT-Trench Thin NPT-Trench PT-Planer (Future) VS (Latest) VS (Conventional)

Eoff - VCE(sat) of 600V Type @V C C =300V, IC =Rated-IC , VGE=+-15V 0.12 Future(Target) 125͠ 0.10 Compact MIP 25͠ 0.08

0.06 ThinThin-NPT-Trench NPT-Trench PT-PlanerPT-Planer UltraUltra-Thin-PT-Trench Thin PT-Trench

Eoff (mJ/A) Eoff (mJ/A) 0.04

0.02

0.00 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 VCE(sat) (V)

INVERTER R&D Switching Waveforms

Clamped inductive load switching at 25C. Red trace SiC, blue trace 1200V hyperfast Si pin diode

25 0

20 -100 15

10 -200

5 -300 0 Id (A) (A) Id Vd (V) (V) Vd -400 -5

-10 -500 -15 -600 -20

-25 -700 0 100 200 300 400 500 0 100 200 300 400 500 Time (ns) Time (ns) current voltage

INVERTER R&D Reverse Recovery Summary 25C Si PiN SiC SiC vs Si Peak reverse current Ipr (A) 12.5 3 24% Reverse recovery time Trr (ns) 37 19 51% Recovered charge Qrr (nC) 231 28 12% Diode loss Eoff Diode PJ) 69 9 13% IGBT loss Eon IGBT PJ) 173 149 86%

125C Si PiN SiC SiC vs Si Peak reverse current Ipr (A) 17.5 3 17% Reverse recovery time Trr (ns) 51 19 37% Recovered charge Qrr (nC) 446 28 6% Diode loss Eoff Di ode (PJ) 139 9 6% IGBT loss Eon IGBT (PJ) 198 149 75%

INVERTER R&D Hybrid Power Inverter Development

Power Inverter Hardware & Analysis for a Hybrid Vehicle Platform

INVERTER R&D PM Synchronous Motor Model

INVERTER R&D PM Synchronous Motor – 15 kW Operation

15 kW Continuous Operating Points 15 kW Peak Operating Points

250.0 1.000 300.0 1.200

200.0 0.800 250.0 1.000

200.0 0.800 150.0 0.600

150.0 0.600

100.0 0.400

100.0 0.400

50.0 0.200 50.0 Torque (Nm) Current (Apk) Voltage (Vrms)(Apk) Torque Current (Nm) Torque (Nm) Current (Apk) Voltage (Vrms) (Vrms) Voltage (Apk) Current (Nm) Torque 0.200

0.0 0.000 0.0 0.000 0 1000 2000 3000 4000 5000 6000 0.0 1000.0 2000.0 3000.0 4000.0 5000.0 6000.0 Motor Speed, RPM Motor Speed, RPM

Torque L-N Vol tage, Vpk Phase Current, Pk Power Pactor l Torque L-N Vo tage, Pk Phase Current, Pk Power Factor

INVERTER R&D Maximum Coolant Temperature – 15 kW Drive

15 kW Inverter - CPM IGBTs / Switch

150

100

50

0

-50 Temperature, C Temperature, -100

Maximum Allowable Coolant Allowable Maximum 12 April 2003 -150 1 2 3 4 Number of IGBT Die Per Switch

8 kHz Swi tch i ng 4 kHz Swi tch i ng 2 kHz Swi tch i ng Phase-Phase Rotation

INVERTER R&D Maximum Coolant Temperature – 25 kW Drive

25 kW Inverter - CPM IGBTs / Switch

150

100

50

0

-50 Temperature, C Temperature,

-100 Maximum Allowable Coolant Coolant Allowable Maximum 12 April 2003 -150 1 2 3 4 Number of IGBT Die Per Switch

8 kHz Swi tch ing 4 kHz Sw tchi ng i 2 kHz Swi tch ing Phase-Phase Rotat ion

INVERTER R&D Voltage Overshoot Reduction

Integrated DC-Bus Snubbers

INVERTER R&D Further Work

• Faster Temperature Sensing of Silicon Junction. Silicon Sensor

Vs • Silicon integration of gate drive and sensing circuits. Thermistor

•EMI containment

- Turn-on speed and diode recovery. - DC Bus Capacitance integrated with Busbar in module.

INVERTER R&D