emi/emc design applications - ansys uk/staticassets/01_em… · emi/emc design applications...

© 2010 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary© 2010 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary

EMI/EMC Design

Applications

Dr.-Ing. Leon Voss

ANSYS Inc.

© 2010 ANSYS, Inc. All rights reserved. 2 ANSYS, Inc. Proprietary

Overview

• Introduction EMC / EMI

• Power Electronics Systems

• Workflow for Inverter Study

• Parasitic extraction

• IGBT characterization

• System simulation

• Emitted fields


Electromagnetic Compatibility

EMC vs. EMI

• Electromagnetic compatibility (EMC) is the

study of the unintentional generation, propagation

and reception of electromagnetic energy

• Electromagnetic interference (EMI) is the

unwanted effect that such energy may induce.

http://en.wikipedia.org/wiki/Electromagnetic_interference



Basic Coupling Modes

Source:

Wikipedia



Emission and Susceptibility

• Emission issues are related to the unwanted

generation of electromagnetic energy by

some source

• Susceptibility or immunity issues, in contrast,

refer to the correct operation of electrical

equipment, referred to as the victim, in the

presence of unplanned electromagnetic

disturbances.


DC Hz kHz MHz GHz ???

HFSS – 2 wavelength long line

– 2 wavelengths are apparent

Low: Maxwell, Q3D

High: HFSS

Maxwell: Quasi Static

Ansoft EM Solvers

Maxwell vs HFSS


D

t

DJH

B

t

ΒΕ

y Electricit forLawsGauss'

Law sAmpere'

MagnetismforLawsGauss'

InductionofLawsFaraday'

0

Differential Form of Maxwell’s

Equations

Full-wave (e.g. HFSS)


D

t

DJH

B

t

ΒΕ

y Electricit forLawsGauss'

Law sAmpere'

MagnetismforLawsGauss'

InductionofLawsFaraday'

0

Example: Maxwell:

Magnetic Transient Formulation

Quasi-Static:

e.g. Maxwell,

Q3D


Variable-Speed Drive

Classical Design Issues


Variable Speed Drive

EMC/EMI Issues

• Classical Design Considerations:

Conducted low-frequency phenomena

– Harmonic Line Currents

(16.7Hz-60Hz, n<= 49

– Interharmonics, Flicker

– Overvoltages

– Harmonic Motor Currents

(0 – 500Hz, n<= 49)

• Analysis of these Phenomena with Simulation

tools like Simplorer is “State of the Art”

Interaction of Converter

with Supply Network

Interaction of Converter

with Motor & Mechanics


Variable-Speed Drive

Developing EMI Issues

Electric Drive Electric Drive

Electric Drive



EMC/EMI Issues

• Developing Issues

– Power electronics being installed closer to

humans (e.g. ICE3 train or Hybrid car)

– Switching Frequencies are increasing

• Higher Radiating Content

• Frequency dependence of electrical parts

becomes more relevant (e.g. skin effect)



EMC/EMI Issues

• Resulting Problems and Challenges

– Bearing Currents (Common mode problem)

– Insulation Fatique

– Losses / Thermal Problems

– Electromagnetic Field Limits

Higher Requirement on Impedance

Characterisation of the system at higher frequencies

Require Simulation techniques not traditionally

applied in this area


AM3~

Traction SupplyPantograph Traction

Motor

InverterInverter LegIGBT Module Top Row

• These power converters are used in high speed trains (TGV)

High Power Inverter Application


• Include package in IGBT

performance

• Electrical Characterization of

the IGBT

• Find switching currents for

power dissipation

• Use power dissipation to

determine environmental

electromagnetic fields


6.5kV IGBT Module Analysis


IGBT Module Pack 3D

accurate model

Parameters

Extraction

Design and Couplings

ModelIGBT Model

• Parasitic model extraction

• IGBT circuit model for System Simulation

Far Field Study

• Far Field Study for Electric Field

• Three-dimensional IGBT pack model


EMC Workflow


• Three-dimensional IGBT pack model

• Parasitic model extraction

• IGBT circuit model

• Far Field Study for Electric Field EM

Quasi-static

Boundary Element

Method

Full-wave

Finite Element

Method

Electronic

Circuit

Simulation


Simulation Techniques


EMI/EMC

Electrical Parasitics Extraction

• Extract the resistance, inductance, capacitance and conductance

(RLCG) parameters of the entire package

Low Frequency High Frequency

Ansoft Q3D

Frequency can have a significant impact on the design performance


• Extracting parameters is straightforward as the nets are

automatically assigned

EMI/EMC

Electrical Parasitics Extraction

Negative Bar

Positive Bar

Phase A

Phase B

Phase C


• Inductance and Resistance are evaluated over frequency

EMI/EMC

Q3D Example R-L Characterisation

Positive Bus –

D2 to INPUT

1.00E-003 1.00E-002 1.00E-001 1.00E+000 1.00E+001 1.00E+002 1.00E+003 1.00E+004 1.00E+005Freq [MHz]

0.10

1.00

10.00

100.00

1000.00

AC

R(N

_b

ar:

U_

d2

,N_

ba

r:U

_d

2)

[mO

hm

]

0.00

10.00

20.00

30.00

40.00

50.00

AC

L(N

_b

ar:

U_

d2

,N_

ba

r:U

_d

2)

[nH

]

Curve Info

ACR(N_bar:U_d2,N_bar:U_d2)

ACL(N_bar:U_d2,N_bar:U_d2)

deign_for_q3dFrequency-dependent Impedance U_d2 - GND ANSOFT

Inductance

Resistance


EMI/EMC

Parasitics Extraction

• The simulation outputs consist of the RLC matrices, one for each frequency

of interest.


EMI/EMC

IGBT Mesh and Field Result

The structure is meshed

using automatic and

adaptive meshing

Current Distribution


• How do we set up the frequency sweep?

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

information up to:

– 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)

stF

2

1max

EMI/EMC

Parasitics Extraction


SheetScan

IGBT Characterization


IGBT Device Generation

Characterization Tool

Extraction of the IGBT Electro-Thermal Parameters

Tran

sfer

ch

arac

teri

stic

curv

e fr

om

dat

ash

eet

Fit

ted

cu

rve

vs. m

easu

red

dat

a

Measured Data

Fitted Curve

Extracted parameter values


IGBT Family

Electro-Thermal Model

DC core

A

Energy calculation

B

Thermal network

F

DC core

A C

Thermal network

F

Capacities C(V), C(I)parasitics L, R, Ccontrolled sources

E

Full parameter excess

Maximum simulation speed:

• Accurate static behaviour

• Accurate thermal response

• No voltage and current transients

• Suitable for system design analysis

Average IGBT Model Dynamic IGBT Model

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


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


Circuit Design based on Parametrized IGBT and Frequency Dependent Model

System Integration

FFT


Vce

Vg

Vge

Ic

Power

The power pulse duration is much smaller than the rise/fall time of Ic and Vce

System Simulation


Circuit Design based on Parametrized IGBT and Frequency Dependent Model

System Integration

-22.50

60.00

0

25.00

50.00

0 240.00m100.00m

2DGraphSel1 NIGBT71.IC

Extract Power Loss

0

474.00m

200.00m

400.00m

100.00 1.00Meg1.00k 3.00k 10.00k 100.00k

2DGraphCon1

GS_I...

FFT


0

474.00m

200.00m

400.00m

100.00 1.00Meg1.00k 3.00k 10.00k 100.00k

2DGraphCon1

GS_I...

Freq. res.

Normalized S para.MagE@10m by

specified inputs

Multiplied magE plots

by Simplorer

Emission Test

Full Wave Effect

Ansoft HFSS


Emitted Fields

For each frequency, the power amplitude is entered

Spectrum (MHz)Power

(W)E field at 1m for 1000w

(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241

Spectrum from Simplorer

Outputs from Simplorer

Inputs for HFSS

Outputs From HFSS

(normalized results)

Fields Levels


Emitted Fields

• Regulators impose

maximum levels of

electric fields close to

electric equipment.

• In the 10-110 MHz

range:

Emax=61V/m

Exposure limits defined by European Community


Emitted Fields

• The E field is very localized

close to the module even at

100 MHz

• However, the very high

power can lead to large

values of E field even far

from the module

• This design is fine at

110MHz.

mag E @ 100 MHz, Power = 10 000W

Spectrum (MHz)Power


(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241

Spectrum (MHz)Power


(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241

Spectrum (MHz)Power


(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241

Spectrum (MHz)Power


(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241

Spectrum (MHz)Power


(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241

Spectrum (MHz)Power


(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241

Spectrum (MHz)Power


(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241

Spectrum (MHz)Power


(V/m)E field at 1m

(V/m)

16.52892562 21439.97604 2.6312 56.41286497

33.05785124 8635.09049 2.7994 24.17307232

49.58677686 5579.619715 2.8731 16.0308054

66.11570248 4131.16773 3.063 12.65376676

82.6446281 3276.823585 3.4045 11.15594589

99.17355372 2712.888158 3.8924 10.55964586

115.7024793 2308.359536 4.4861 10.35553171

132.231405 2022.75744 4.905 9.921625241


The virtual test of the whole

car body

Setting the IGBT package

Mesh: 187,137 CPU time: 14m6s (Pentium M, 2GHz)


Noise transfer between an

IGBT package and a cable

50 ohm 50 ohm

50 ohm 1k ohm

Mesh: 254,966 CPU time: 34m41s (Pentium M, 2GHz)


One more sample

Mesh: 830,769 CPU time: 4h50m (Pentium M, 2GHz)


The Virtual Test

The Whole Car Body


Conclusions

• EMC in power electronics systems can be

studied in a simulation environment by

considering:

– Frequency-dependent system impedances

(parasitics)

– Electrical dynamics of switching devices

– Radiation effects using full-wave FEM

• Software Integration of Simplorer, Q3D, HFSS

allows efficient system simulation

emi/emc design applications - ansys uk/staticassets/01_em… · emi/emc design applications...

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