Simulation-Based Performance Characterization T M

© 2008 Ansoft, LLC All rights reserved. Ansoft, LLC Proprietary

Simulation Based Performance Characterization of an Electric Drive Train System

Authors: Zed (Zhangjun) Tang, Wendy Lei

Presenter: Scott Stanton

Ansoft LLC


Electric Drive Train Configuration

Energy Storage Unit

Traction Motor

Generator

Drive Cycle

ICE Engine

Power Electronics

Control Unit

Electrical Grid

ICE: Internal Combustion Engine


Electric Drive Train Example

300 Volt Battery Pack

2-Mode Transmission

Power Electronics

Full-Size SUV 2-Mode Hybrid

Controller

ICE

Traction Motor

Chevrolet Tahoe


Electric Drive Train Applications

http://www.simplorer.com/english/simplorer_index.htm


Contents

• Efficiency Map of Traction Motor• Equivalent Circuit Model Extraction• Vector Controller• Conclusions• Future Work


Basis for Research – 2004 Toyota Prius


Contents

• Efficiency Map of Traction Motor• Equivalent Circuit Model Extraction• Vector Controller


Efficiency Map of Traction Motor

Synchronous MotorPhasor Diagram

Synchronous MotorLosses

Q Axis D Axis


Use Transient with Motion for Accurate Losses Calculation

Transient with Motion


Eddy Losses on Permanent Magnets

Assign zero current to the permanent magnets:

Jtot = 0Apply boundary condition to each magnet


Extract the Capability Curve of IPM

Idealized Torque vs. Speed Curve Comparing with Capability Curve

ConstantTorque

ConstantPower

Output Torque

Motor Speed


0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00Primary Sweep

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

Y1

Ansoft Corporation Maxwell2DDesign1Torque vs. Load Angle @ CurrentsCurv

Optimal Torque Output at Different Currents


Efficiency Map of Traction Motor

Speed (RPM)

Out

put T

orqu

e (N

*m)

Effi

cien

cy (%

)


Contents

• Efficiency Map of Traction Motor• Equivalent Circuit Model Extraction• Vector Controller


ECE Method

IA

IB

ICΘ

Input Variables

Output Parameters- λa, λb, λ

c

- Torque

Goal: Create a state space type equivalent circuit extracted (ECE) model from magnetostatic FEA parametric solution for use in a system simulation


System Representation

Where:

Torque

Theta

Bac

k EM

F

Inputs:Ia, Ib, Ic, Theta

Outputs:EMF: Va, Vb, VcTorque

CurrentIa, Ib, Ic

dtdV

LI

T

mT

λλλ

=

+=


• Assume Wye connected winding• IA = Im * cos(Θ

* PolePairs - β )

• IB = Im * cos(Θ

* PolePairs - β – 120)• IC = Im * cos(Θ

* PolePairs - β – 240)

• Let phi = Θ

* PolePairs - β• Independent

Solution Method

IA

IB

IC

Iy

Ix

• Dependent


Input Parameter Variations

• Im from 0 to Imax : 9 steps• Beta from 0 to 330 deg: 30 steps• Rotor angle: 0 to 60 electrical deg: 10 steps• Total number of solutions:

• 9 * 30 * 10 = 2700 independent solutions

Good for rapid design using Distributed Solve Option (DSO)


DSO – Distributed Solve Option

…

Host

Nodes


User Defined Simplorer®

Models


Simplorer®

ECE Circuit

ECE - LINKECE - LINKECE - LINKECE - LINK

Beta_IN Im_IN Theta_IND

D

D

ω +

+Φ

GAIN

GAIN

GAIN

GAIN

GAIN

GAIN

GAIN

GAINn

GAIN

ATAN2 GAINIxb

Ixc

Iyb

Iyc

A

A

A

RA

RB

RC

L1

L2

L3

e1

e3

e2

IA

IB

IC

Coordinate transformation realized using VHDL-AMS


Verify ECE Model Against FEA Transient

• Open Circuit Back EMF

0.000 0.002 0.004 0.006 0.008 0.010 0.012Primary Sweep

-300.00

-200.00

-100.00

0.00

100.00

200.00

300.00

Y1

Ansoft Corporation OC_EMFBack EMFCurve Info

InducedVoltage(PhA)Setup1 : Transient

InducedVoltage(PhB)Setup1 : Transient

InducedVoltage(PhC)Setup1 : Transient

Y Component 1Imported



0.0005 0.0010 0.0015 0.0020 0.0025 0.0030Primary Sweep

190.00

200.00

210.00

220.00

230.00

240.00

Y1

Ansoft Corporation OC_EMFBack EMF

Curve Info avg

InducedVoltage(PhA)Setup1 : Transient 225.0685

InducedVoltage(PhB)Setup1 : Transient -105.5390

InducedVoltage(PhC)Setup1 : Transient -102.5586

Y Component 1Imported 224.6388

Y Component 2Imported -105.1177

Y Component 3Imported -102.3206


Verify ECE Model Against FEA Transient

• Unbalanced Phase Currents

0.000 0.002 0.004 0.006 0.008 0.010 0.012Primary Sweep

-0.40

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

0.40

0.50

Y1

Ansoft Corporation Test_tranXY Plot 2Curve Info

FluxLinkage(PhA)Setup1 : Transient

FluxLinkage(PhB)Setup1 : Transient

FluxLinkage(PhC)Setup1 : Transient




0.000 0.002 0.004 0.006 0.008 0.010 0.012Primary Sweep

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

0.40

0.50

Y1

Ansoft Corporation Test_tran1Flux LinkageCurve Info







0.000 0.002 0.004 0.006 0.008 0.010 0.012Primary Sweep

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

Y1

Ansoft Corporation Test_tranFlux LinkageCurve Info








Contents

• Efficiency Map of Traction Motor• Equivalent Circuit Model Extraction• Vector Controller• Energy Storage Sub-system• System Integration


Vector Control with Step Load






Vector Control with Ramp Load, Mfg. IGBT and Deadtime Control


Vector Control with Ramp Load, Mfg. IGBT and Deadtime Control


Maximum Torque per Ampere (MTPA) and Field Weakening Control

Voltage and Current Limitation Equations

lim22

lim22

)()( UiLiLu

Iiii

qqfddes

qds

≤++=

≤+=

ψω



id, iq calculation equations for field weakening control

22lim

22

lim

dq

d

qq

edd

fd

iIi

LiL

LU

Li

−=

⎟⎟⎠

⎞⎜⎜⎝

⎛−⎟⎟

⎠

⎞⎜⎜⎝

⎛+−=

ωψ



For this IPM exported from RMxprt: lim/ ILdf >ψSo, there is no such control phase with maximal constant output power

( ) ( )( )

( )

q

fdde

q

ddq

dqe

fqfq

d

fd

L

iLU

i

LLL

LLULL

Li

22

lim

22

lim2

4

8

ψω

ωψψ

ψ

+−⎟⎟⎠

⎞⎜⎜⎝

⎛

=

−

−⎟⎟⎠

⎞⎜⎜⎝

⎛+−

+−=



MTPA Control

Field Weakening Control

lim/ ILdf >ψStable:li/ ILdf >ψ



From the calculation equation of ideal maximal speed:

)*(* lim

limmax ILP

U

df −=Ω

ψ

We can get the maximal speed is 5475 rpm, which coincides with the simulation result.




Future Work

• Field-weakening that includes accurate FEA model

• Energy Storage Sub-system• System Integration



fψToo steep because the Ld, Lq and calculated by RMxprt are not precise enough for FWC. FEA model is recommended.


Conclusion

• Efficiency Map of Traction Motor– Calculated Using Transient FEA

• Equivalent Circuit Model– Extracted Based on Static FEA

• Torque-Speed Capability– Implemented Using Vector Control

• Field-weakening Controller – Implemented to Enhance the Vector Control


References

•Report on Toyota/Prius Motor Torque Capability, Torque Property, No- Load Back EMF, and Mechanical Losses, J. S. Hsu, Ph.D., C. W. Ayers, C. L. Coomer, R. H. Wiles, Oak Ridge National Laboratory

•Report on Toyota/Prius Motor Design and manufacturing Assessment, J. S. Hsu, C. W. Ayers, C. L. Coomer, Oak Ridge National Laboratory

•Evaluation of 2004 Toyota Prius Hybrid Electric Drive System Interim Report, C. W. Ayers, J. S. Hsu, L. D. Marlino, C. W. Miller,G. W. Ott, Jr.,C. B. Oland, Oak Ridge National Laboratory

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Simulation-Based Performance Characterization T M