High Power IGBT Inverter Design - Ansys

High Power IGBT Inverter Design 

Marius Rosu PhD, EM Product Manager 

Scott Stanton, Technical Director 

Leon Voss PhD, Senior AE 

Vincent Delafosse, Senior AE 

© 2009 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary

Objectives 

• ANSYS Multiphysics Inverter Design Flow 

– High Power System Design Concept 

• IGBT Electro-Thermal Model 

– Average 

– Dynamic 

• IGBT Package Thermal Model 

– Extracted from CFD 

– IGBT Package Mechanical Stress Analysis 

• Thermal Stress 

• Electromagnetic Forces 

– EMC/EMI Analysis 

• Parameter Extraction: R, L, C, G 

• Radiated Emissions – Full Wave Effects 


Outline 

ANSYS Icepack 

Ansoft SIMPLORER 

Ansoft Q3D 

Ansoft ANSYS Simplorer 

Mechanical 

Ansoft HFSS 

ECELink 

ECE ECE - - LINK 

LINK 

© 2009 ANSYS, Inc. All rights reserved. 3 ANSYS, Inc. Proprietary 

+ 

W 

IA 

A 

E 

IB 

A 

IC 

A 

E 

E 

EQU 

Ixa := 

Ixb := IB.I 

Ixc := IC.I 

Ix := Ixa + 

Iya 

Iyb := IB.I 

Iyc := IC.I 

Iy := Iya + 

Im := sqrt(Ix^ 

delta := at 

D 

D 

D 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

sourceA1 

sourceA2 

sourceB1 

sourceB2 

sourceC1 

sourceC2 

ICA: 

GAIN 

57.3 

CONST 

CONST 

Magnet01 

Magnet02 

FEA 

ANGRA 

+ 

Φ 

-30+PWM_P 

-60+PWM_P 

CONST -90+PWM_P 



+ 

ω

High Power Inverter System 

Multiphysics Design Concept 



ANSYS Mechanical 

Model Order Reduction 

ANSYS Icepack 


Current profile 

Ansoft Maxwell/RMxprt 


Temperature profile 


IGBT Family 

Electro-Thermal Model 

Average IGBT Model Dynamic IGBT Model 

A 

DC core 

B 

Energy calculation 

Thermal network 

Maximum simulation speed: 

• Accurate static behaviour 

• Accurate thermal response 

• No voltage and current transients 

• Suitable for system design analysis 

F 

A C 

DC core 

Capacities C(V), C(I) 

parasitics L, R, C 

controlled sources 

Full parameter excess 

Thermal network 

Maximum simulation accuracy: 

• Sophisticated semiconductor based model 

• Accurate static, dynamic and thermal 

behaviour 

• Accurate gate voltage and current waveforms 

• Suitable for drive optimization, EMI/EMC 


E 

F

IGBT Device Generation 

Characterization Tool 

Transfer characteristic 

curve from datasheet 

Fitted curve 

vs. measured data 

Extraction of the IGBT Electro-Thermal Parameters 

Measured Data 

Fitted Curve 

Extracted parameter values 


The Average IGBT Model 

• Three main parts 

– static core 

– thermal network 

– energy calculation section 

• Parameters extracted through characteristic curves 


The Average IGBT Model (2) 

• Switching V and I waveforms are square 

• Switching losses are calculated at each switching period 

• Turn-ON/OFF power pulses are injected into thermal network 

• Amplitude of the rectangular power pulses are calculated 

• PON/POFF – Switching Power 

• EON/EOFF – Energy losses 

• PDC – Conduction power dissipation; 

• TON/TOFF – Power injection pulse durations 

• Vce,sat – Saturation collector-emitter voltage 


The Dynamic IGBT Model 

• Dynamic IGBT shares the same static the Average model 

• The switching energy of the Dynamic IGBT model is the direct 

integration of the switching voltage and current 


The Dynamic IGBT Model (2) 

• Dynamic IGBT accurately captures the switching waveforms 

• Suitable for EMI/EMC analysis 


IGBT Package 

Thermal Model: Technical Background 

ANSYS Icepack 

• Temperature rise at any point in the system is the sum of the 

independently derived temperature increase attributable to each heat 

source in the system 

• Assumptions: 

– Temperature assumed to be a linear function of heat sources 

– This requires that the fluid flow is constant (for each study) and density 

and all properties are constants 


IGBT Package (2) 

Thermal Model: Technical Background 

⎡ΔT1 

( t) 

⎤ 

⎢ ⎥ 

⎢ 

ΔT2 

( t) 

⎥ = 

⎢ M ⎥ 

⎢ ⎥ 

⎢⎣ 

ΔTn 

( t) 

⎥⎦ 

⎡θ 

⎢ 

⎢ 

ϕ 

⎢ 

⎢ 

⎣ϕ 

11 

21 

M 

n1 

( t) 

( t) 

( t) 

ϕ 

θ 

ϕ 

12 

22 

M 

n2 

( t) 

( t) 

( t) 

L 

L 

O 

L 

Foster network 

ϕ 

ϕ 

θ 

( t) 

⎤ 

⎥ 

( t) 

⎥ 

M ⎥ 

⎥ 

( t) 

⎥⎦ 

[ ] T 

h ( t) 

h ( t) 

L h ( t) 


1n 

2n 

nn 

Each matrix element 

is a complete thermal 

transient response curve 

1 

2 

n

IGBT Package Thermal Model 

Implementation 

T − T 

P 


Z 

th 

( t) 

ΔT 

= 

P 

= 

ref


Validation 

• Simple 4-node system 

• Air at a constant speed of 1 m/s 

2 

1 


4 

3


Blue-measurement data Red-fitted results 

Node 1 – self-heating Node 1 – Due to Source 2 

Node 1 – Due to Source 4 Node 1 – Due to Source 3 



Validation 

Temperature at Node 1 with constant heat flux applied at all 4 nodes 

Temperature at Node 1 with time-variant heat flux 


IGBT Inverter Design 

High Power System Analysis 

Ansoft SIMPLORER V8.1 

DC Current Profile 

Line Current 

Profile 


IGBT Inverter Design 

Mechanical Stress Analysis 

Ansoft Maxwell V13.0 coupled with ANSYS Mechanical R12.1 

Input 

DC Current Profile 

Input 

Line Current 

Profile 

Mapping Power Loss Thermal-Structural 

Mapping Electromagnetic Force 


IGBT Inverter Design (2) 

Mechanical Stress Analysis 


EMI/EMC 

Electrical Parasitics Extraction 

• Extract the resistance, inductance, capacitance and conductance 

(RLCG) parameters of the entire package 

Frequency can have a significant impact on the design performance 

Ansoft Q3D 

Low Frequency High Frequency 


EMI/EMC 

Electrical Parasitics Extraction 

• Extracting parameters is straightforward as the nets are 

automatically assigned 

Negative Bar 

Phase A 

Phase B 

Phase C 

Positive Bar 


EMI/EMC 

IGBT Mesh and Field Result 

The structure is meshed 

using automatic and 

adaptive meshing 

Current Distribution 


EMI/EMC 

Parasitics Extraction 

• How do we set up the frequency sweep? 

– Nyquist sampling: To capture a time step of Ts, obtain frequency domain 

information up to: 

F 

max 

1 

= 

2× 

t 

– For a time domain waveform with a risetime of 80 ns, in order to capture the 

ringing in the time domain, we would want to capture at least 4 samples during 

this risetime. This implies a sampling time of 20 ns 

• We need to solve up to 50 MHz (= 1/20ns) 


s

EMI/EMC 

Parasitics Extraction 

• The simulation outputs consist of the RLC matrices for different frequencies 


System Integration 

Circuit Design based on Parametrized IGBT and Frequency Dependent 

Model 


60.00 

50.00 

25.00 

-22.50 

System Integration (2) 

0 

ECELink1 


LINK 

2DGraphSel1 NIGBT71.IC 

0 100.00m 

240.00m 

Extract Power Loss 

+ 

W 

FFT 


IA 

A 

EA 

IB 

A 

IC 

A 

E 

EC 

474.00m 

400.00m 

200.00m 

0 

EQU 

Ixa := 

Ixb := IB.I * 

Ixc := IC.I * 

Ix := Ixa + 

Iya : 

Iyb := IB.I * 

Iyc := IC.I * 

Iy := Iya + I 

Im := sqrt(Ix^2 + 

delta := ata 

D 

D 

D 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

sourceA1 

sourceA2 

sourceB1 

sourceB2 

sourceC1 

sourceC2 

ICA: 

2DGraphCon1 

GAIN 

57.3 

CONST 

CONST 

Magnet01 

Magnet02 

FEA 

ANGRAD 

+ 

Φ 

-30+PWM_PER 

-60+PWM_PER 

CONST -90+PWM_PER 



+ 

ω 

100.00 1.00k 3.00k 10.00k 100.00k 1.00Meg 

GS_I...

474.00m 

400.00m 

200.00m 

Full Wave Effect 

0 

2DGraphCon1 

100.00 1.00k 3.00k 10.00k 100.00k 1.00Meg 

Multiplied Multiplied magE magE plots plots 

by by Simplorer Simplorer 

Emission Test 

GS_I... 

Ansoft HFSS 

MagE@10m by 

specified inputs 

Freq. res. 

Normalized S para. 


The Virtual Test 

The Whole Car Body 


Conclusion 

ANSYS Icepack 


Ansoft Q3D 

Ansoft ANSYS Simplorer 

Mechanical 

Ansoft HFSS 

ECELink 


LINK 


+ 

W 

IA 

A 

E 

IB 

A 

IC 

A 

E 

E 

EQU 

Ixa := 

Ixb := IB.I 

Ixc := IC.I 

Ix := Ixa + 

Iya 

Iyb := IB.I 

Iyc := IC.I 

Iy := Iya + 

Im := sqrt(Ix^ 

delta := at 

D 

D 

D 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

EQUBL 

sourceA1 

sourceA2 

sourceB1 

sourceB2 

sourceC1 

sourceC2 

ICA: 

GAIN 

57.3 

CONST 

CONST 

Magnet01 

Magnet02 

FEA 

ANGRA 

+ 

Φ 

-30+PWM_P 

-60+PWM_P 




+ 

ω

High Power IGBT Inverter Design - Ansys

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