2011 ANSYS, Inc. June 8, 2012 1

Electric Machines Considering Power Electronics

Zed (Zhangjun) Tang, Ph.D.

Presented at ANSYS Confidence by Design

June 5, 2012

2011 ANSYS, Inc. June 8, 2012 2

Machine Design Methodology Introduction RMxprt Maxwell Advance Capabilities Core Loss Demagnetization / Magnetization Field-Circuit Co-Simulation Maxwell Circuit Editor Simplorer Capabilities, Switches, IGBT Characterization

Simplorer Examples Multi-Physics Force Coupling Thermal Coupling

Outline

2011 ANSYS, Inc. June 8, 2012 3

Introduction: Machine Design Methodology

2011 ANSYS, Inc. June 8, 2012 4

Maxwell 2-D/3-D Electromagnetic Components

Field Solution

Model Generation

HFSS

ANSYS

Mechanical Thermal/Stress

ANSYS CFD Fluent

PExprt Magnetics

RMxprt Motor Design

Maxwell Design Flow Field Coupling

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Simplorer System Design

PP := 6

ICA:

A

A

A

GAIN

A

A

A

GAIN

A

JPMSYNCIA

IB

IC

Torque JPMSYNCIA

IB

IC

TorqueD2D

HFSS, Q3D, SIwave

ANSYS CFD Icepack/Fluent

Maxwell 2-D/3-D Electromagnetic Components

ANSYS

Mechanical Thermal/Stress

PExprt Magnetics

RMxprt Motor Design

Simplorer Design Flow System Coupling

Model order Reduction

Co-simulation

Push-Back Excitation

2011 ANSYS, Inc. June 8, 2012 6

RMxprt - Initial Motor Design Analytical solution

16 different Motor/Generator types Input data geometry, winding layout saturation, core losses comprehensive results

machine parameters

performance curves

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Parametric Sweep:

Stack_Length

Skew/no Skew

Stator_ID

AirGap

Monitor:

Torque

Power

Efficiency

Determine the Best Design

Create FEA Model

Export Circuit Model

RMxprt - Motor Design

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Integrated EMDM Foundations Auto Setup Maxwell Design from RMxprt

2011 ANSYS, Inc. June 8, 2012 9

Maxwell/RMxprt V15 Axial Flux Machine

AC or PM Rotor Single or Double Side Stator

Sample Inputs

Sample Outputs

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Maxwell/RMxprt V15 Axial Flux Machine Maxwell 3D auto-setup (Geometry, Motion, Master Slave, Excitations, etc. )

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Design Exploration

P2 - parallel

P1 - cond

Workbench Schematic

Maxwell Project

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Design Exploration

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Design Exploration Six Sigma

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More Than 30 UDP Machine Components for 2D and 3D

Integrated Motor Solution

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RMxprt Dynamic Link to Simplorer

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Maxwell

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Time [ms]

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

Pos

ition

[mm

]

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

Coi

l Cur

rent

[met

er]

TRW / Ansoft Position & Current Hysteresis Control Close/Open1

Curve Info

Position

Coil Current

Diode Current

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Automatic Adaptive Meshing

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Advanced Capabilities Coreloss Computation

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Lamination Core Loss in Time Domain

Instantaneous hysteresis loss

Instantaneous classic eddy current loss

Instantaneous excess loss

where

dt

dBH

dt

dBBktp irrmhh

cos

1)(

2

22

1)(

dt

dBktp cc

dCe 2/

0

5.15.1 cos2

2

21

)(dt

dBk

Ctp c

e

e

2011 ANSYS, Inc. June 8, 2012 23

Core Loss Effects on Field Solutions

Basic concept: the feedback of the core loss is taken into account by introducing an additional component of magnetic field H in core loss regions. This additional component is derived based on the instantaneous core loss in the time domain

2011 ANSYS, Inc. June 8, 2012 25

Model Validation by Numerical Experiment

The effectiveness of the model can be validated by the power balance experiment from two test cases: considering core loss feedback and without considering core loss feedback. The increase of input electric power and/or input mechanical power between the two cases should match the computed core loss.

0

20

40

60

80

100

120

140

160

0 20 40 60 80 100

Time (ms)

Lo

ss (

W)

Input power increaseCore loss 0

2

4

6

8

10

12

0 5 10 15 20 25 30 35 40

Time (ms)

Lo

ss (

W)

Core loss

Input power increase

Three-phase transformer Three-phase motor

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Advanced Capabilities Demagnetization Modeling

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Modeling Mechanism

The worst demagnetization point for each element is dynamically

determined from a full transient

process

The demagnetization point is source, position, speed and

temperature dependent

Each element uses its own recoil curve derived at the worst

demagnetization point in

subsequent transient simulation

H Hc

B

0

Br'

Br

K

p Recoil lines

Worst demagnetizing point

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H Hc

B

0

Br'

Br

K

p Recoil line

Irreversible Demagnetization

If a demagnetizing point P goes below the knee point K, even after the load is reduced or totally removed, the subsequent working points will no longer along the original BH curve, but along the recoil line.

The animation shows how the demagnetization

permanently occurs with varying load current

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Benchmark Example

8-pole, 48-slot, 50 KW, 245 V, 3000 rpm Toyota Prius IPM motor with imbedded NdFeB magnet

Two steps in 3D transient FEA: 1. Determine the worst operating point element by element

during the entire transient process

2. Simulate an actual problem based on the element-based linearized model derived from the step 1

To further consider the impact of temperature, element-based average loss density over one electrical cycle is used as the thermal load in subsequent thermal analysis

The computed temperature distribution from thermal solver is further feedback to magnetic transient solver to consider temperature impact on the irreversible demagnetization

2011 ANSYS, Inc. June 8, 2012 33

Hc' change in one element during a transient process:

The 1st cycle (0 to 5ms) doesnt consider temperature impact. The 2nd cycle (5 to 10ms) has considered the feedback from thermal solution based on the average loss over the 1st cycle

Observation: Hc' has dropped from 992,755 A/m to 875,459 A/m, which is derived from the worst operating condition

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Contours of loss density distribution Static temperature distribution (K)

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Torque profiles showing demagnetization and temperature dependence:

Torque profiles derived from without considering demagnetization, considering demagnetization but no temperature impact and considering demagnetization as well as temperatures dependence

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Magnetization

Compute magnetization based on the original non-remanent B-H curve

Find operating point p from nonlinear solutions

Construct line b at the operating point p, which is parallel to the line a at saturation point

Br is the intersection of line b with B-axis

Element by element

B

H 0

Br Line b

Slope of line a at saturation point

p

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Br

Magnetostatic case: the operating point used for computing

magnetization (Br) is from single

source point;

What is the Difference between Using Magnetostatic and Transient solver?

Transient case: the operating point used for

computing magnetization (Br)

is the maximum operating

point with the largest (B,H)

during the entire transient

simulation.

H 0

Br p

B

H 0

p

B

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Anisotropic magnetization: magnetization direction is determined by the orientation of the magnet material and the direction is specified by a

user;

Anisotropic or Isotropic Magnetization

P(T) input

Q(T) input

Isotropic magnetization: magnetization direction is

determined by the orientation of

the magnetizing field and is

determined during the f