integrated simulation environment for electric machine design uk/staticassets/hev... · integrated...

Scott StantonScott StantonTechnical DirectorTechnical Director

Advanced Technology InitiativesAdvanced Technology Initiatives

Scott StantonScott StantonTechnical DirectorTechnical Director

Advanced Technology InitiativesAdvanced Technology Initiatives

Integrated Simulation Integrated Simulation Environment for Electric Environment for Electric Machine Design Machine Design

ANSYS Inc.ANSYS Inc.ANSYS Inc.ANSYS Inc.

Design Automation Example:

RMxprt - Maxwell

UDP: User Defined Primitives

Thevenin equivalent

(impedance matrix,

source voltages)

2D/3D FEA

External Circuit Coupling:

Maxwell - Simplorer

Lumped field

parameters

(inductances, induced

Internal voltages)System

Simulator

System/Circuit - FEA Coupling:

Simplorer - Maxwell

Differentiating FeatureExample: Axial-Disk PM Motor Control

Current Control Loop

Position Control Loop

External Circuit Coupling

Axial Motor – Speed & Torque Profile

3ph Line Current Profile

Flux Linkage ProfileDifferentiating Feature

Magnetic Flux Density

Axial Motor – Speed & Torque Profile

• Nonlinear lamination is extensively used in low

frequency electromagnetic devices for significant

reduction of eddy current loss.

Nonlinear Lamination and

Nonlinear Anisotropy

Differentiating Feature

• Nonlinear anisotropy is widely used in magnetic

recording, power transformers and large size electrical

machines. Oriented electrical steels have high induction

but with much lower core loss in the rolling direction.

Nonlinear Lamination and

Nonlinear Anisotropy

Example: Reluctance Motor ApplicationDifferentiating Feature

The rotor local coordinate system is attached to the

moving rotor

Rotor lamination is defined along r direction in the local

cylindrical coordinate system

PM Characteristic to 2nd & 3rd

Quadrant

• Expand the existing

algorithm to the 3rd

quadrant for demag

computation

Differentiating FeatureB

Load line without other

sources

Load line with other

sources

Initial Br

Br after

• Base on the actual

user-input B-H

curve in the 3rd

quadrant

Demagnetization point

Hc after

demagnetization

Generator Fault Example

• 550 W PM generator

• 4 Pole

• 3 Phase, 50HZ AC

• Ceramic 8D PM

• Rated Speed,

Open-Circuit to

Short-Circuit Fault

Magnet

• 2nd quadrant demagnetization (demag)

• Spatially dependent demag due to fault

Initial Radial Magnetization

80.00Ansoft LLC Maxwell3DDesign23D_EMF_save_demag ANSOFT

Curve Info

InducedVoltage(PhaseA)Setup1 : Transient

InducedVoltage(PhaseB)Setup1 : Transient

80.00Ansoft LLC Maxwell3DDesign23D_EMF_save_demag ANSOFT

Curve Info

Short-Circuit Analysis

• Short circuit at 15.2ms: Phase A peak

0.40Ansoft LLC Maxwell3DDesign2BH_Data_Points_Initial_Demag ANSOFT

Material BH Curve

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00Time [ms]

-80.00

-25.00

Volts [V]

Setup1 : Transient

InducedVoltage(PhaseC)Setup1 : Transient

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00Time [ms]

-80.00

-25.00

Volts [V]

Setup1 : Transient

Bus short for all phases

-3.00E+005 -2.00E+005 -1.00E+005 0.00E+000H [A/m]

Material BH Curve

Operating Points

• Subsequent use of the magnet results in

reduced performance

80.00Ansoft LLC Maxwell3DDesign33D_EMF_demaged ANSOFT

Curve Info

InducedVoltage(PhaseA)

80.00Ansoft LLC Maxwell3DDesign33D_EMF_demaged ANSOFT

Curve Info

InducedVoltage(PhaseA)

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00Time [ms]

-80.00

-25.00

Volts [V]

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00Time [ms]

-80.00

-25.00

Volts [V]

Addt’l short for all phasesWeak Back EMF

-3.00E+005 -2.00E+005 -1.00E+005 0.00E+000H [A/m]

Ansoft LLC Maxwell3DDesign3BH_Data_Points_Demag ANSOFT

-3.00E+005 -2.00E+005 -1.00E+005 0.00E+000H [A/m]

Ansoft LLC Maxwell3DDesign3BH_Data_Points_Demag ANSOFT

Operating Points

• Leading edge is weakened significantly

Volts [V]

Ansoft LLC Maxwell3DDesign23D_EMF_save_demag ANSOFT

Volts [V]

Ansoft LLC Maxwell3DDesign23D_EMF_save_demag ANSOFT

Original

0.00 5.00 10.00 15.00Time [ms]

-80.00

-25.00

Volts [V]

Ansoft LLC Maxwell3DDesign33D_EMF_demaged ANSOFT

0.00 5.00 10.00 15.00Time [ms]

-80.00

-25.00

Volts [V]

Ansoft LLC Maxwell3DDesign33D_EMF_demaged ANSOFT

0.00 5.00 10.00 15.00Time [ms]

-80.00

-25.00

0.00 5.00 10.00 15.00Time [ms]

-80.00

-25.00

• Mesh a higher percentage

• Higher mesh quality

• Effective on imported geometries

• Matching boundary more robust

• Fewer total elements

• Smoother and more uniform element transition

Robust Mesher

• Smoother and more uniform element transition

• Automatically healing and repair

High Quality Mesh

Using Minimal Settings

Special Attention given

to Air Gap Region

Induced Eddy Currents in

Magnets

Symmetry

0 .0 0 2 .0 0 4 .0 0 6 .0 0 8 .0 0 1 0 .0 0 1 2 .0 0T i m e ( m s ) [ s ]

0 .1 0

0 .2 0

0 .3 0

0 .4 0

0 .5 0

0 .6 0

0 .7 0

0 .8 0

0 .9 0

1 .0 0

Loss [W

A n s o ft C o rp o ra t i o n N o S p l i t _ S MN o r m a l i z e d P o w e r L o s s C u r v e In f o

N o r m a liz e d P o w e r L o s s

Im p o r t e d

N o r m a liz e d P o w e r L o s s

End of Rotor

Symmetry

Boundary

PM Loss Reduction

Add cuts:

− Reduce Eddy Currents

− Reduce Loss

Up to 32 Magnet Segments

Power Loss in Magnet vs. Number

of Segments

Normalized Loss with Carrier Harmonics

∑ ∫

Lossσ

1 2 4 8 16 32

PMSM – Core Loss Calculation

echFe PPPP ++=

Core Loss is Expressed as the Sum of:

Hysteresis Ph

Classical Eddy Current Pc

Excess Loss Pe

∑∑= =

++−=m

mijiemijicmijihvijech

BfkBfkBfkpkkkerror1 1

25.15.1222 )]([),,(

Minimizing the Error:

m: number of loss curves

ni: number of points of the i-th loss curve

Pvij = f(fi , Bmij): two dimensional lookup table for multi-frequency loss curves

5.122 )()( memcmhFe BfkBfkBfkP ++=echFe PPPP ++=

Integrated EM Field and Core

Loss Analysis

Core Loss Effects on Input Power and Force/Torque

Eddy current produced by B

Eddy current produced B

Eddy current produced by Bn Eddy current produced Bt

Reference: D. Lin, P. Zhou and Q. M. Chen, “The Effects of Steel Lamination Core Losses on Transient Magnetic Fields Using T-Ω Method”,

IEEE VPPC, September 3-5, 2008, Harbin, China

Core Loss

Ansoft Corporation Test_tranXY Plot 1Curve Info avg

Sinusoidal Excitation, 60Hz Curve 2.2892

Sine plus 1kHz triangular wave, 60Hz Curve 3.3764

Sine plus 1kHz triangular wave, multiple CL Curves 3.8978

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00Time [ms]

oss [kW

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00Time [ms]

oss [kW

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00Time [ms]

oss [kW

Core Loss Effect on Torque

Ansoft Corporation Test_MagnetLossXY Plot 3

Curve Info

Torque Not Including CL Effect

Curve Info

Torque Not Including CL Effect

Torque Including CL Effect

Curve Info

Torque Difference

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00Time [ms]

16.00 18.00 20.00 22.00 24.00 26.00 28.00 30.00 32.00Time (ms) [s]

3 Phase Induction Motor Losses

• Core loss

• Rotor copper loss at no-load condition

– Due to flux pulsations in the air gap

– Difficult to measure

– Are present in every squirrel cage induction

– Are present in every squirrel cage induction motor

• Two induction motors in the 200 kW range that only differ in the slot design

– Both motors have 48 rotor slots

– Stators have 60 and 36 slot for motors A and B respectively

Reference: J.Germishuizen, S.Stanton “No Load Loss and Component

Separation for Induction Machines”, Proceedings ICEM 2008, Paper ID 1144

No Load Losses

Why the big

difference

between the two

designs?

Input power: 36 Stator slots

Noticeable difference between input power and copper losses with different

stator slot number.

Input power: 60 Stator slots

Stator Winding Loss

FEA Rotor Copper Losses

Where:

Jz is the current density

ρr is the resistivity of the rotor bar

l is the stack length

n is the total number of bars

A is the cross-sectional area of a bar

An is the cross-sectional area of a bar

Measurement vs. Simulation

Maxwell Transient Results

Measured Results

60 Slots 36 Slots

ULL V 569.3 512.5

A 96.3 123.0

PCuskW 1.0 1.3

PCurkW 0.7 6.5

PFe kW 1.2 1.5

Motor with its cage removed.

The no load loss without the

cage requires a special

measurement setup to rotate the

rotor with the same speed as the

stator rotating field.

Measured Results

60 slot with cage

36 slot without cage

36 slot with cage

Maxwell Results

Manufacturing Factor for Iron Loss

• Iron core losses are calculated based on kh, kc and keusing near perfect samples of laminated materials.

Other factors that contribute to core loss include:

– Lamination Punching, Stress and Heat

– Other Losses such as intra-lamination currents

60 Slots 36 Slots

Reference: J.Germishuizen, S.Stanton “No Load Loss and Component Separation for Induction

Machines”, Proceedings ICEM 2008, Paper ID 1144

60 Slots 36 Slots

Workflow : Coupled Electromagnetic

and Thermal Analysis for Electric

Machines

Geometry

Losses

Maxwell Model

CFD Model

Mapped Losses

TemperatureANSYS Mechanical/

PMDC Motor

Integrated Design Flow

Customer Requirements

Create Initial Design.

Map of solution domain

Torque

Current

Voltage

Customer Requirements Map of solution domain

T, ψd, ψq = f(id, iq,Θ )using Static Solver

ScaleN, L

Integrating FEM in an everyday design environment to accurately calculate the performance of IPM motors, J.Germishuizen, S.Stanton and V. Delafosse

ISEF 2009 - XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering Arras, France, September 10-12, 2009

Integrated Solution:

Customer Requirements

Create Initial Design.

Map of solution domain

Torque

Current

Voltage

Verify with Transient

Customer Requirements Map of solution domain

T, ψd, ψq = f(id, iq,Θ )using Static Solver

ScaleN, L

Integrating FEM in an everyday design environment to accurately calculate the performance of IPM motors, J.Germishuizen, S.Stanton and V. Delafosse

ISEF 2009 - XIV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering Arras, France, September 10-12, 2009

Cogging Torque Optimization

• Motivation:

– Primary Contributor to:

• Torque Ripple

• Mechanical Vibration

• Acoustic Noise

• Drive System Instability

– Thus: Lower Efficiency

• Goals:

– Reduce Cogging Torque

– Maintain Machine Performance

Method

• PM Shape Modification

– Pole Embrace

– Pole Arc Offset

– Magnet Thickness

Ansoft Corporation Maxwell2DDesign1Torque

Curve Info

Moving1.Torque

Setup1 : Transient

Ansoft Corporation PMSM_CTXY Plot 2

Curve Info

Bradial

Setup1 : Trans ient

Time='0ns'

– Magnet Thickness

• Transient FEA

• Genetic Optimization Algorithm

– Minimize Peak Cogging Torque

– Maintain Average Air Gap Flux Density

0.00 5.00 10.00 15.00Time [s ]

0.00 0.20 0.40 0.60 0.80 1.00

Norm alizedDis tance

Nominal Setup

• PM Geometric Parameters

– Pole Embrace = 0.75

– Pole Arc Offset = 0 mm

– Magnet Thickness = 3.5 mm

• Calculations

– Torque: Virtual Work Method

– Average Radial B in Air Gap:

• Brad = Bx*cos(ϕ) + By*sin(ϕ)

Ansoft Corporation Maxwell2DDesign1Torque

Curve Info

Moving1.Torque

Setup1 : Transient

Ansoft Corporation PMSM_CTXY Plot 2

Curve Info

Bradial

Setup1 : Transient

Time='0ns'

Nominal Solution

2.2 N-m

Avg = 0.76 T

0.00 5.00 10.00 15.00Time [s]

0.00 0.20 0.40 0.60 0.80 1.00Norm alizedDis tance

∫ ∫ •Θ

consti dVdHBd

0))((|

Virtual Work MethodMagnetic Field Eqn.

• Cogging Torque Peak Nominal Value = 2.2 N-m

– Optimal Goal = 0.2 N-m

– G1 = 1 + (max(abs(Torque)) – 0.2) * 9 / 5.3– When Cogging Torque = 0.2 N-m, then G1 = 1.0

• Nominal Bavg Value = 0.76 Tesla

– Optimal Goal = 0.76 Tesla

– G2 = 1 + (Brad_Avg – 0.5) * 9 / 0.31– When Air Gap Flux Density = 0.76 T, then G2 = 8.55

• Magnet Area Minimize

–G3 = 1 + (Mag_area – 220) * 9 / 290– When Magnet Area = 220 mm2, then G3 = 1.0

Results

-2 .00

-1 .00

A ns o f t Co r po ra tion PMSM_CT_V er if yC og g in g Torq u e

0 .1 4 0 2

2 .2 2 7 1

0 .4 3 5 40 .5 8 7 7

Curv e In f o

O p timiz ed Des ign

S e tup1 : Trans ien t

Mov ing1 .To rque

Impor ted

Nomina l Des ign

Ansof t Corporation PMSM_CT_VerifyAir Gap Flux Density

--- Nominal (0.76 T)

--- Optimized (0.73 T)

0 .00 1 .00 2.00 3 .00 4.00 5 .00 6.00 7 .00 8.00Tim e [s ]

-3 .00

-2 .00

M X 2 : 5 .4 0 3 1M X 1 : 0 .6 3 7 9

--- Nominal (2.2 N-m peak)

--- Optimized (0.4 N-m peak)

0.00 0.20 0.40 0.60 0.80 1.00NormalizedDistance

Curve Info

Bradial

Setup1 : Transient

Time='0ns'

Bradial

Imported

Nominal Design

Summary

integrated simulation environment for electric machine design uk/staticassets/hev... · integrated...

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