Ansoft Maxwell v12 User Guide Machine Design Reference Guide

Ansoft Electrical Machine Design Reference Revision: June, 2008

Ansoft Maxwell Field Simulator V12—Electric Machine Design Reference

2


3

Project

Manager

Window

Properties

Window

Message

Window

History Tree

Window

3D Modeler

Window

Progress

Window


4


5

Toolbar: 2D Objects Toolbar: 3D Objects

Rotate around

current axis Zoom In/Out Fit selected

Rotate

around

model

center

Rotate

around

screen

center

Dynamic

zoom

Fit all

Pan


6


7

General Shortcuts

• Help: F1

• Context help: Shift + F1

• Close program: CTRL + F4

• Copy: CTRL + C

• New project: CTRL + N

• Open: CTRL + O

• Save: CTRL + S

• Print: CTRL + P

• Paste: CTRL + V

• Cut: CTRL + X

• Redo: CTRL + Y

• Undo: CTRL + Z

• Cascade windows: CTRL + 0

• Tile windows horizontally: CTRL + 1

• Tile windows vertically: CTRL + 2

3D Modeller Shortcuts

• Select face/object behind current selection: B

• Face select mode: F

• Object select mode: O

• Select all visible objects: CTRL + A

• Deselect all objects: CTRL + SHIFT + A

• Fit view: CTRL + D

• Zoom in, screen center: CTRL + E

• Zoom out, screen center: CTRL + F

• Shifts the local coordinate system temporarily: CTRL + Enter

• Drag: SHIFT + Left Mouse Button

• Rotate model: Alt + Left Mouse Button

• Zoom in / out: Alt + SHIFT + Left Mouse Button

• Switch to point entry mode (i.e. draw objects by mouse): F3

• Switch to dialogue entry mode (i.e. draw object solely by entry in command and attrib-utes box.): F4

• Render model wire frame: F6

• Render model smooth shaded: F7

• Set model projection to standard

isometric projections: Alt + Double Click

Left Mouse Button at points on screen

• ALT + Right Mouse Button + Double

Click Left Mouse Button at points on

screen: give the nine opposite projec-

tions

Predefined View Angles


8

RMxprt and Maxwell are now fully integrated.

All RMxprt data is exported to Maxwell 2D in

version 12. This includes geometry, materials,

excitations, boundaries, motion setup, solution

setups, mesh operations, result plots, etc.

For Maxwell 3D, this includes geometry and

materials

Full Integration of RMxprt and Maxwell


9

Motion setup

Boundaries

Excitations

Mesh operations

Solve setup

Results plots

Materials

Geometry

Ready to solve! In menu bar, click on

Maxwell 2D > Analyze All

Full Integration of RMxprt and Maxwell


10

Materials

Geometry

Integration to 3D: Geometry with Skew and

End-turn, Materials


11


12


13


14


15


16


17


18


19


20


21


22

Symmetry: Even (Flux Normal)

Symmetry: Odd (Flux Tangential)


23 (Flux can exit and re-enter the bound- (Flux can not escape the bound-


24


25


26


27


28

Surface Deviation is the maximum spacing, in drawing units, that

the triangle surfaces may be from the true-curved geometry’s

surface

Normal Deviation is the maximum angular difference, in degrees,

that a triangle face’s normal can have from the surface normal for

the true geometry which it is meant to represent

Aspect Ratio refers to the maximum allowed aspect ratio of all faces


29


30


31


32

3. A Band object is required for Transient simulations with motion.

2. A Band object is recommended in Magnetostatic simulations, but not required. The

band is a dummy air/vacuum object between moving and stationary parts.

1. To assign Torque/Force calculation in a Magnetostatic simulation: select the

object (s) > right mouse click > Assign Parameters

4. In a Transient simulation, moving torque is assigned by the solver automatically.

5. The moving torque calculated in a Transient simulation is the torque on all objects

INSIDE the band (not including the band). For a Magnetostatic simulation, a user

must manually assign the torque parameter on all objects inside the band.

6. A Force calculation can also be assigned in the Transient solver in Maxwell 2D V12.

There is no limit on how many forces can be calculated. This is not the case for V11.


33


34


35


36


37

Double click

View > Set Solution Context ...


38

Parametrics: Define one or more variable sweep definitions, each specifying a series of variable values within a range. Easily view and compare the results using plot or table to determine how each design variation affects the performance of the design.

Optimization: Identify the cost function and the optimization goal. Optimetrics automatically changes the design parameter(s) to meet the goal. The cost function can be based on any solution quantity that can be computed, such as field values, R,L,C force, torque, volume or weight.

Sensitivity: Determine the sensitivity of the design to small changes in variables in the vicinity of a design point. Outputs include: Regression value at the current variable value, first derivative of the regression, second derivative of the regression.

Tuning: Variable values are changed interactively and the performance of the design is monitored. Useful after performing an optimization in Optimetrics to fine tune the optimal variable value and see how the design results are affected.

Statistical: Shows the distribution (Histogram) of a design output like force, torque or loss caused

by a statistical variation (Monte Carlo) of input variables.


39

Geometry

Excitation

Materials

Frequency

Speed

Torque/Force

Inductance


40


41


42


43

Parametric variations: 1296

Solve time, one processor: 13 hr, 15 min

Solve time, distributed, 8 CPUs: 2 hr, 30 min

Speed improvement: 5.3X

Ansoft Maxwell Field Simulator V12 – Training Manual P1-1

Permanent Magnet Synchronous Machine

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Ansoft Corporation PMSM_CTXY Plot 2Curve Info

BradialSetup1 : TransientTime='0ns'

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ewto

nMet

er]

Ansoft Corporation PMSM_CT_VerifyCogging Torque

0.1402

2.2271

0.43540.5877

MX2: 5.4031MX1: 0.6379

Curve Info

Optimized DesignSetup1 : Transient

Moving1.TorqueImported Nominal Design

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Cor

eLos

s [k

W]

Ansoft Corporation PMSM_OC_EMFCore Loss

Curve InfoCoreLoss

Setup1 : Transient

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-150.00

-100.00

-50.00

0.00

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150.00

Y1 [V

]

Ansoft Corporation PMSM_OC_EMFXY Plot 2

Curve Info

InducedVoltage(PhaseA)Setup1 : Transient

InducedVoltage(PhaseB)Setup1 : Transient

InducedVoltage(PhaseC)Setup1 : Transient


Permanent Magnet Synchronous Machine: Contents

RMxprtBasic Theory

Review Example

Add Unique Winding Arrangement

Setup Parametric Problem

Export Design to Maxwell 2D

Maxwell: Cogging TorqueReview Maxwell Setup

Create Variables

Apply Mesh Operations

Solve Nominal Problem

Setup Optimization Problem

Review Pre-Solved Optimization Results

Maxwell: Open Circuit Back EMFDefine Material Core Loss Characteristics

Set Lamination and Stack Factor

Consider Power Loss in Magnets

Solve Problem and Review Results

Maxwell: Rated Condition – Functional Voltage Source

Modify Rotor Geometry using UDP’s

Winding Setup Definitions and Variable Definition

Choosing Optimal Time Step

Solve Problem and Review Results

Drive DesignCreate a Machine Model

Use the Model in Circuit Simulation

Notes:

1. RMxprt/Maxwell V12 or higher is required

2. Basic knowledge of electric machine is required

3. Basic understanding of Finite Element is required


Electric Machine Design Suite

A Complete Solution for Modern Electric Machines and Drives Design

Equivalent Circuit Model : High Fidelity Physics Based Model

Fast Analytical Solution: Narrow the Design Space

Parametric AnalysisOptimization

Magnetostatic/Eddy Current Analysis using FEA

Parametric AnalysisOptimization

AHAJA ×∇×+×∇+∇−∂∂−=×∇×∇ vV

t cs σσσυ

scf

ff

ff uu

dtid

LiRddtdA

aSlN

d =+++Ω∫∫ 0=−dt

duCi cf

Field Equation:

Circuit Equation:

Motion Equationexternalem TTm +=+λωα

Simultaneous Equations:

Transient Analysis using FEA

Parametric Analysis

A_PHASE_N1

A_PHASE_N2

B_PHASE_N1

B_PHASE_N2

C_PHASE_N1

C_PHASE_N2

ROTB1

ROTB2

EMSSLink1

EMF2

RA

RB

RC

A

IA

A

IB

A

IC

1750.023

0.023

0.023

theta>90 AND theta<150theta>150 AND theta<210

theta>210 AND theta<270

theta>270 AND theta<330theta>330 OR theta<30

ICA:


EMF1 175

E1

R1

E2

R2

E3

R3

E4

R4

E5

R5

E6

R6

ctrl_1:=OFFctrl_6:=OFF

ctrl_1:=ON

ctrl_6:=ONctrl_1:=ONctrl_2:=ON


ctrl_2:=ONctrl_3:=ON

ctrl_2:=OFF



ctrl_5:=ON

ctrl_6:=ON


ctrl_3:=OFF



A AM_IGBT

+ VVBC

+ VVGE4

MASS_ROTB1

Drive System Integration with Manufacturer’s IGBTs

EMF

A

IA

A

IB

A

IC

175

ICA:

EMF 175

A AM_IGB

V+ VVBC

A_PHASE_N1

B_PHASE_N1

C_PHASE_N1

ROT1

ROT2

ECE

ECELink

T

FM_ROT

PP:=

ON:=

OFF:=

THRESH:=4

HYST:=

EQU theta_elect := PP * ECELink

theta := MOD(theta_elect

ωω+IGBT

IGBT IGBT

IGBTIGBT

D2 D3

Drive System using System Level IGBT’s and Analytical Motor Model

Phase CurreIAIBIC

t

1.00

-1.00

0

-500.0

500.0

0 17.27m10.00m

TorquTo

t

400.0

-100.0

0

200.0

0 17.2710.00

Phase VoltagV_A

t

300.0

-300.0

0

-200.0

200.0

0 17.2710.00

Von Mises stress

Thermal and Stress Analysis

A_PHASE_N1

A_PHASE_N2

B_PHASE_N1

B_PHASE_N2

C_PHASE_N1

C_PHASE_N2

ROTB1

ROTB2

EMSSLink1

EMF2

RA

RB

RC

A

IA

A

IB

A

IC

1750.023

0.023

0.023

theta>90 AND theta<150theta>150 AND theta<210


theta>270 AND theta<330theta>330 OR theta<30

ICA:


EMF1 175

E1

R1

E2

R2

E3

R3

E4

R4

E5

R5

E6

R6


ctrl_1:=ON

ctrl_6:=ONctrl_1:=ONctrl_2:=ON



ctrl_2:=OFF



ctrl_5:=ON

ctrl_6:=ON


ctrl_3:=OFF



A AM_IGBT

+ VVBC

+ VVGE4

MASS_ROTB1

Complete Transient FEA -Transient System Co-simulation

Design Requirements

Size/Weight EfficiencyTorqueSpeedCogging/RippleInverter MatchingThermalStressManufacturabilityCost


RMxprt: Background

ASSM: Adjustable-Speed Synchronous MachineRotor speed is controlled by adjusting the frequency of the input voltage

Unlike brushless PMDC motors, ASSM does not utilize the position sensors.

Rotor can be either inner or outer type

Can operate as a generator or as a motorMotor Mode:

Sinusoidal AC source

DC source via a DC to AC inverter

Generator Mode:Supplies an AC source for electric loads


ASSM: Background

Input voltage U is the reference phasor, let the angle I lags U be φ, the power factor angle

Let the angle I lags E0 be ψ. The d- and the q-axis currents can be obtained respectively as follows:

ϕ−∠= II

=

=

ψψ

cossin

III

q

dI

q

d1

II−= tanψ


ASSM: Background

OM can be used to determine the direction of E0

Let the angle E0 lags U be θ, which is called the torque angle for the motor, then the angle ψ is

For a given torque angle θ :

Solving for Id and Iq yields:

)jj( aq11 XXROM ++−= IU

θϕψ −=

−

−=

− θ

θsin

cosU

EUII

XRRX 0

q

d

q1

1d

−−+−

+=

θθθθ

sin)cos(sin)cos(

UXEURUREUX

XXR1

II

d01

10q

qd21q

d


ASSM: Background

The power factor angle φ is

The Input electric power is

The Output mechanical power is

Pfw : Frictional and Wind Loss

PCua: Armature Copper Loss

PFe : Iron-core Loss

Torque:

Efficiency:

θψϕ +=

ϕcos31 UIP =

)(12 FeCuafw PPPPP ++−=

ω2

2PT =

%100PP

1

2 ×=η


RMxprt: Base Project

Open the RMxprt project located on your desktop by double clicking on PM_SyncMotor.mxwl

Save the project under a new name:File > Save As > c:\Training\PM_SyncMotor.mxwl

Select Setup1 under Analysis and click the Right Mouse Button (RMB) and Choose Analyze


RMxprt: Results

Select Setup1, click the RMB and choose Performance

Choose a Solution Set


RMxprt: Results

Select Setup1, click the RMB and choose Performance

Choose a Performance Curve


RMxprt: Add New Winding Arrangement

1

2

3

Double click on Stator > WindingClick on Whole-CoiledSelect Editor



In the Winding Editor Panel, click the RMB and select Edit Layout

Deselect Constant PitchChange the Layout as shown



View the new winding arrangement by placing the mouse over one of the A phase coils in the drawing window and click the RMB selecting Connect One Phase Coils.


RMxprt: Performance

Solve the problem by selecting Setup1 under Analysis and click the Right Mouse Button (RMB) and Choose AnalyzeSelect Setup1, click the RMB and choose Performance


RMxprt: Add Variables

Click on Winding and in the Properties window, next to Conductors PerSlot type in CPS

Click on Stator and in the Properties window, next to Length type in Depth

1

2

1

2


RMxprt: Add Variables

Click on Rotor and in the Properties window, next to Length type in Depth

Select menu item RMxprt > Optimetrics Analysis > Add Parametrics


RMxprt: Parametric Setup

Click on Add and setup the two variables as follows:

Click on the Calculations Tab > Setup Calculations and add the followingCurrent > RMSLineCurrentParameter

Power > OutputPowerParameter

Misc. > EfficiencyParameter

1

2

3

4


RMxprt: Parametric Solution

Select ParametricSetup1 under Optimetrics, click the RMB and Analyze

Select ParametricsSetup1, click RMB and select View Analysis ResultsSelect Table and then click on Efficiency Parameter

Efficiency increased from 89% to over 98% while maintaining output power


RMxprt: Create Maxwell Design

Select Setup1, click the RMB and select Create Maxwell Design

2

deselect

Choose

4

1

3


Maxwell 2D: Base Design

Material Assignment

Motion

Boundaries

Winding

Mesh

Results

Soln. Setup


Maxwell 2D: Cogging Torque, Excitation

Select the PhaseA winding, click the RMB and select PropertiesChange the Type to Current with a value of zero

Repeat this for PhaseB and PhaseC


Maxwell 2D: Cogging Torque, Mesh Ops

Select Length_Magnet under Mesh Operations, click the RMB and select Properties

Decrease the size of the element by half. Just type in 3.75/2


Maxwell 2D: Cogging Torque, Mesh Ops.

Select Length_Main under Mesh Operations, RMB and select Properties

Decrease the size of the element by 4. Just type in 10.96/4



Select SurfApprox_Mag under Mesh Operations, RMB and select Properties

Decrease the length of the “Maximum Surface Deviation” to 190 nm. This yields an angular segmentation of Θ = 0.25 deg.

))2/cos(1( Θ−= rDr is the inside radius of the stator which is 81mm



Select SurfApprox_Main under Mesh Operations, RMB and select Properties

Decrease the length of the “Maximum Surface Deviation” to 190 nm



Three possible operations:

D D = Maximum Surface Deviation

ro

ri

SFoAspectRati

DSFro

ri

DrShapeFactoro

ri

1

)3(*3

)2(*2

=

=

=1

AR=2

Θ

))2/cos(1( Θ−= rD

rΘ = Maximum Surface

Normal Deviation

2

Aspect Ratio of Cells,not of triangles



Select Band in the modeler tree, RMB and select Properties

Decrease the SegAngle value to 0.25 degrees

NOTE!: This small value for angular segmentation, 0.25deg, is neededonly for very sensitive calculations such as Cogging Torque


Maxwell 2D: Cogging Torque, Mechanical Setup

Select Motion Setup1 under Model, RMB to select PropertiesSelect Mechanical Tab and change speed to 1 deg/sec

Select Setup1 under Analysis and RMB to select Properties


Maxwell 2D: Cogging Torque, Solution Setup

Change to Save Fields tab

31

2


Maxwell 2D: Cogging torque, Results

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ing1

.Tor

que

[New

tonM

eter

]

Ansoft Corporation Maxwell2DDesign1Torque

Curve Info

Moving1.TorqueSetup1 : Transient

Since the speed is held constant at 1.0 deg/sec, the X-Axis represents both time and position, i.e. 10 sec = 10 deg

Solve the cogging torque problem by selecting Setup1 under Analysis, RMB and select Analyze:

Once the problem is solved double click on Results > Torque

Click the RMB in the plot and select Export Data. Save the plot on the desktop.



Select menu item View > Set Solution Context, and choose zero seconds.

In the drawing window hit

CTRL+A to select all objects,

RMB to select Fields > A >Flux_Lines



Double Click on Legend to change plot properties



Select Flux_Lines1 under A under Field Overlays, RMB to select Animate


Maxwell 2D: Cogging torque, Rename Design

Rename Maxwell2DDesign1 by selecting its name in the project tree, RMB and select Rename. Change the name to PMSM_CT for Permanent Magnet Synchronous Motor Cogging Torque.


Maxwell 2D: Cogging torque, Variables

Select CreateUserDefinedPart under Mag_0 under NdFe30_N and choose Properties

1

2

3

In the Value field type in the name PoleEmbrace


Maxwell 2D: Cogging Torque, Optimization Variables

Change the field for the ThickMag to MagnetThickness and accept the default value of 7.5mm

1

2



Change the field for the Offset to PoleOffset and accept the default value of 0mm.

1

2



Select CreateUserDefinedPart under InnerRegion under Vacuum and choose Properties

In the Value field type in the names: PoleEmbraceMagnetThicknessPoleOffset

1

2



Select CreateUserDefinedPart under Rotor under M19_26G_SF0.950 and choose Properties

In the Value field type in the names: PoleEmbraceMagnetThicknessPoleOffset

1

2



Select menu item Maxwell 2D > Design Properties and change the value of the variables just defined:

Select the Optimization radio button and Include each variable:



Modify the variable to see the effect on the geometry

Pole Offset

PE

MT

For this exercise, the range for each is:6.5 mm < MagnetThickness < 9.5 mm0.6 < PoleEmbrace < 0.90 < PoleOffset < 30 mm


Maxwell 2D: Cogging Torque Optimization, Air Gap Arc

Create an arc in the air gap to be used for post processing purposes, by selecting menu item Draw > Arc > Center Point

Using the mouse select the origin, any point in the air gap along the X axis and any point in the air gap at the 45 degree angle. Any value used if valid, it will be modified in the next step.

1

2

3Double click to end


Maxwell 2D: Cogging Torque Optimization, Air Gap Arc

Select CreateAngularArc under CreatePolyline under Polyline1 under Lines, RMB and select Properties

Change the value for the starting point to 80.8, 0, 0. This will place the arc between the band object and the stator ID

Select Polyline1. In the Properties window change its name to AG_Arc


Maxwell 2D: Cogging Torque Optimization, Variables

Select menu item Maxwell 2D > Field > CalculatorPerform the following commands to calculate the radial component of the flux density in the air gap

Quantity > B

Scal? > Scalar X

Function > PHI

Trig > cos

Multiply *

Quantity > B

Scal? > Scalar Y

Function > PHI

Trig > sin

Multiply *

Add + -- this gives Bx*cos(PHI) + By*sin(PHI)

Add … > Name: Bradial -- this adds the express to the stack



Continue to calculate the average radial component of the air gap flux density

Select Bradial under Named Expressions

Copy to Stack

Geometry > Line > AG_Arc

Integrate

Number > Scalar > Value = 1

Geometry > Line > AG_Arc

Integrate

Divide / -- this give the average radial flux density in the air gap

Add … > Name: Brad_Avg -- this adds this expression to the stack



Continue to calculate the area of the permanent magnetNumber > Scalar > Value = 1

Geometry > Surface > Mag_0

Integrate

Number > Scalar > Value = 1e6 -- this converts from m2 to mm2

Multiply *

Add … > Mag_Area -- this adds this expression to the stack

Select the Maxwell 2D Design PMSM_CT and in the Properties window change the variables back to their default values

Even though the design variables and thus the geometry has changed, once the design variables are set to their previous values, the solution is automatically reloaded; there is no need to solve the problem again.



Plot the radial flux density in the air gap by selecting Results, RMB to select Create Field Report > Rectangular Plot


Maxwell 2D: Cogging Torque Optimization, Brad AG

Plot B_rad on the AG_Arc

2

3

4

5

7

10

1

6

8 9


Maxwell 2D: Cogging Torque Optimization, Brad AG

Plot of B radial in air gap at time zero

0.00 0.20 0.40 0.60 0.80 1.00Norm alizedDis tance

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0.00

0.20

0.40

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0.80

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Bra

dial

Ansoft Corporation PMSM_CTXY Plot 2Curve Info


Click the RMB in the plot window and select Export Data. Save the plot on the desktop.


Optimization: Solution Setup

Change the Stop Time of the Simulation from 15 seconds to 3.75 sec. The cogging torque waveform is symmetric after 3.75 deg (equal to 3.75 sec) and to save simulation time we only need to solve up to this point.

Select Setup1 under Analysis and RMB to select Properties



Select Optimetrics and RMB to select Add > Optimization

Next to Optimizer select Genetic Algorithm


Maxwell 2D: Cogging Torque Optimization Setup

Click on Setup

Change the values as shown here



Cogging Torque Peak Nominal Value* = 2.2 N-mMaximum Value** = 5.5 N-m

Optimal Goal = 0.2 N-m (subjectively chosen, we want to reduce CT by >10x)

Normalize Solution Range: 1 to 10G1 = 1 + (max(abs(Torque)) – 0.2) * 9 / 5.3

Objective: G1 = 1.0

*Note: The Peak Nominal Value is when:MagnetThickness = 7.5 mmPoleEmbrace = 0.85PoleOffset = 0 mm

**Note: The Maximum Value is determined when these values are a Maximum:MagnetThickness = 9.5 mmPoleEmbrace = 0.90PoleOffset = 0 mm

The maximum value of cogging torque may lay outside these parameter values, i.esomewhere else in the solution domain. These values are used just to define a range for the objective.



Nominal Bavg Value = 0.76 TeslaRange*: 0.50 < Bavg < 0.81 Tesla Optimal Goal = 0.76 Tesla (we want to maintain the Air Gap Flux Density)Normalize Range: 1 to 10

G2 = 1 + (Brad_Avg – 0.5) * 9 / 0.31Objective: G2 = 8.55

Magnet AreaRange*: 220 < Mag_area < 510 mm2

Normalize Range: 1 to 10G3 = 1 + (Mag_area – 220) * 9 / 290Objective: G3 = 1.0

*Note: The Range was calculated by simulation the minimum and maximum values:MagnetThickness … 6.5 mm and 9.5 mmPoleEmbrace … 0.6 and 0.9PoleOffset .. 0 mm and 30 mm



In the Calculation Expression field type in the function as shown below

1 2 3

4

5



Include Calculation for the average radial component of the flux density in the air gap

Type in the rest of the expression and then click on Add Calculation

2 3 4

1

5



Include calculation for Magnet Area

Type in the rest of the expression and then click on Add Calculation

1

2 3

4



For the calculation expressions for Brad_Avg and Mag_Area click on Calc. Range and select 0ns for time zero

1

3

2



Set the Goal and Weigh for each objective

Cost1 = (G1 – 0.2)2 * W1 where G1 = max(abs(Torque))

Cost2 = (G2 – 0.75)2 * W2 where G2 = abs(AirGap_Bavg)

Cost3 = (G3 – 230)2 * W3 where G3 = Mag_area

Cost = Cost1+Cost2+Cost3

Note: The Cogging Torque and Air Gap Flux Density have equal weight, which is twice that of the magnet area



Click on the Variables tab and change the values accordingly:

This problem takes too long to solve during the class. The full solution can be downloaded from Ansoft’s FTP site:

ftp://ftp.ansoft.com/download/ChinaTraining/PM_SyncMotor_Opt.zip

To solve the problem, select OptimizationSetup1 under Optimetrics, RMB and select Analyze


Maxwell 2D: Cogging Torque Optimization Results



Since the field solution was not saved for each variation in theoptimization solution, create a second Maxwell 2D design and solve the problem with the optimized design variable values.

Select the Maxwell 2D design PMSM_CT, RMB and select Copy

Select the project name PM_SyncMotor, RMB and select Paste

Select the Maxwell 2D design PMSM_CT1, RMB and select Rename, and change the design name to PMSM_CT_Verify


Maxwell 2D: Cogging Torque Optimization Verify

Select the design PMSM_CT_Verify and in the Properties window change the design variables to the Optimized value

Increase the Stop Time to 7.5 sec and then solve the design:

1 2

3



Plot the Cogging Torque

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-0.30

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-0.10

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0.10

0.20

0.30

0.40

0.50

Opt

imiz

ed D

esig

n [N

ewto

nMet

er]

Ansoft Corporation PMSM_CT_VerifyCogging TorqueCurve Info




In the plot window RMB to select Import Data and pick the cogging torque plot that was exported earlier.

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-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

Y1

[New

tonM

eter

]

Ansoft Corporation PMSM_CT_VerifyCogging Torque

0.1402

2.2271

0.43540.5877

MX2: 5.4031MX1: 0.6379

Curve Info


Moving1.TorqueImported Nominal Design In plot window, RMB

and select Marker > Add X Marker

Optimized Design

Nominal Design



Plot the air gap flux density

0.00 0.20 0.40 0.60 0.80 1.00NormalizedDistance

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Brad

ial

Ansoft Corporation PMSM_CT_VerifyAir Gap Flux Density

Curve Info



Maxwell 2D: AG Flux Density

In the plot window RMB to select Import Data and pick the Air Gap flux density plot that was exported earlier.

0.00 0.20 0.40 0.60 0.80 1.00NormalizedDistance

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Bra

dial

Ansoft Corporation PMSM_CT_VerifyAir Gap Flux Density

Curve Info


BradialImported Nominal Design


Maxwell 2D: AG Flux Density

Determine the average air gap flux density.

3

4The target optimized value is 0.76T

1

2


Maxwell 2D: Magnet Area

Determine the magnet area.

21

The area of the magnet for the nominal design was 383 mm2

3


Maxwell 2D: Open Circuit Back EMF

Select the design PMSM_CT_Verify, RMB and select Copy

Select the project PM_SyncMotor, RMB and select Paste

Select the new design PMSM_CT_Verify1, RMB and select Rename. Change the name to PMSM_OC_EMF


Maxwell 2D: Open Circuit Back EMF

Select MotionSetup1 under Model, RMB to select Properties

Select the Mechanical tab and change the speed to 3600 rpm


Maxwell 2D: Open Circuit Back EMF, Core Loss Setup

Calculate the core loss coefficients from multiple core loss curves



Select the Stator and in the Properties widow click on the material M19_26G_SF0.950 and then select View/Edit Material

1

3

2



Add the core loss curve for 60Hz

1

2

3 Choose the file M470-65A-60Hz.tab4

5



Add the core loss curve for 100Hz

1

2

3 Choose the file M470-65A-100Hz.tab4

5



Continue to add the following curves:M470-65A-200Hz.tab M470-65A-400Hz.tab

M470-65A-600Hz.tab M470-65A-700Hz.tab M470-65A-1kHz.tab


Maxwell 2D: Open Circuit Back EMF, Magnet Loss

Select Mag_0 and in the Properties next to Materials click on NdFe30_N and then on View/Edit Materials.

Change the conductivity to 625000 S/m

Material properties are global quantities, the affect all designs. Thus when modifying materials that are common to various designs, thesolutions to the designs become invalid.



Select Mag_0, RMB to select Assign Excitation > Current

By assigning zero current to the magnet it is assured that total current into and out of this magnet is zero. If there were more than one magnet, each one should have a separate excitation of zero amps.



Select Excitations, RMB to select Set Eddy Effect


Maxwell 2D: Open Circuit Back EMF, Core Loss

Select Excitations, RMB to select Set Core Loss. Add Core Loss for the Rotor and Stator


Maxwell 2D: Open Circuit Back EMF, Solution Setup

Modify the solution setup by selecting Setup1, RMB and select Properties

1

2

The time step is determined by:

sec3.46deg1

secdeg21600

sec60min1*deg360*

min3600

urevrev

==

The frequency is 240 Hz, which gives a period of 4.2 msec. Thus 10 msec is ~2.5 cycles


Maxwell 2D: Open Circuit Back EMF, Results

Solve the transient problem by selecting Setup1 under Analysis, RMB to select Analyze

After the problem is solved, click on Results, RMB to select Create Transient Report > Rectangular Plot

1

23



0.00 2.00 4.00 6.00 8.00 10.00Time [ms]

-150.00

-100.00

-50.00

0.00

50.00

100.00

150.00Y

1 [V

]

Ansoft Corporation PMSM_OC_EMFXY Plot 2

Curve Info






Click on Results, RMB to select Create Transient Report > Rectangular Plot

12

3



0.00 2.00 4.00 6.00 8.00 10.00Time [ms]

0.00

0.20

0.40

0.60

0.80

1.00

1.20C

oreL

oss

[kW

]

Ansoft Corporation PMSM_OC_EMFCore Loss

Curve InfoCoreLoss

Setup1 : Transient


Maxwell 2D: Rated Condition

To solve the problem for the rated condition, select the Maxwell 2D design PMSM_OC_EMF, RMB and select CopySelect the project name PM_SyncMotor, RMB and select Paste

Select the Maxwell 2D design PMSM_OC_EMF1, RMB and select Rename, and change the design name to PMSM_Rated

Delete the Mag_0, Rotor,and InnerRegion


Maxwell 2D: New Rotor Geometry

Select menu item Draw > User Defined Primitive > SysLib > RMxrpt > IPMCore. Modify the Values as shown below.



Select the object IPMCore1 and then Edit > Arrange > Rotate

Select Modeler > Boolean > Split

Select Edit > Arrange > Rotate and use -45 degrees about the Z axisSelect Modeler > Boolean > Split in the XZ Plane Keeping Fragments on the Negative SideSelect Edit > Arrange > Rotate and use +45 degrees about the Z axis



Select IPMCore1 and in the Properties windowName: Rotor

Material: M19_26G_SF0.950

Select Rotor, RMB to select Edit > CopyIn the drawing window, RMB to select Edit > PasteSelect CreateUserDefinedPart under Rotor1, RMB to select Properties

Change InfoCore to 1

Select Rotor1 and then Maxwell Model > Boolean > Separate Bodies. This will create two magnets. Change the name of the magnets to Mag_0 and Mag_1and change their color.



Select Rotor, RMB to select Edit > CopyIn the drawing window, RMB to select Edit > PasteSelect CreateUserDefinedPart under Rotor1, RMB to select Properties

Change InfoCore to 2

Select Rotor1 and in the Properties windowName: Duct

Material: Vacuum


Maxwell 2D: Rated Condition, PM Setup

Select Mag_0 and in the Properties window click on the material M19_26G_SF0.950 and select NdFe30 and then Clone Material(s)

1

2

3



Change the name to NdFe30_NV for North Pole V Core

Repeat the same for Mag_1

Cartesian CS with the pole aligned with the X axis



The drawing tree should look like this



A local coordinate system needs to be create for each magnet. Zoom into Mag_0. Select the Create Relative CS Icon

2

3

1

A local CS is create with X and Y axis as shown. Magnetization will be along the X axis4



Zoom into Mag_1. Select the Create Relative CS Icon

3

1

2

A local CS is create with X and Y axis as shown. Magnetization will be along the X axis4



Select Mag_0 and in the Properties Window change Orientation to RelateiveCS1

Select Mag_1 and in the Properties Window change Orientation to RelateiveCS2


Maxwell 2D: Rated Condition, PM Mesh Ops.

Select Mag_0 and Mag_1, RMB to assign mesh operations


Maxwell 2D: Rated Condition, Excitation

Select Rotor, Mag_0, Mag_1, and Duct. Select Moving1 under Motion, RMB to select Add Selected Object

Select PhaseA under Excitations, RMB to select Properties

163.299 * sin(2*pi*240*time+18.2635*pi/180)



Select PhaseB and then PhaseC under Excitations, RMB to select Properties.

VB = 163.299 * sin(2*pi*240*time+18.2635*pi/180-2*pi/3)VC = 163.299 * sin(2*pi*240*time+18.2635*pi/180-4*pi/3)



Select Excitation, RMB to select Setup Y Connection

2

3

1


Maxwell 2D: Rated Condition, Solution Setup

Select MotionSetup1 under Model, RMB to select Properties and then Data to change the Initial Position, and then Mechanical to set the speed

Select Setup1 under Analysis, RMB and select Properties

This problem takes too long to solve during the class. The full solution can be downloaded from Ansoft’s FTP site:

ftp://ftp.ansoft.com/download/ChinaTraining/PM_SyncMotor_Rated.zip


Maxwell 2D: Rated Condition, Results

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ing1

.Tor

que

[New

tonM

eter

]

Ansoft Corporation PMSM_RatedTorque Quick ReportCurve Info


0.00 50.00 100.00Time [ms]

-4000.00

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-1000.00

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1000.00

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Y1

[A]

Ansoft Corporation PMSM_RatedWinding Currents

Curve Info

Current(PhaseA)Setup1 : Transient

Current(PhaseB)Setup1 : Transient

Current(PhaseC)Setup1 : Transient

85.00 87.50 90.00 92.50 95.00 97.50 100.00Time [ms]

1.20

1.30

1.40

1.50

1.60

1.70

1.80

1.90

Cor

eLos

s [k

W]

Ansoft Corporation PMSM_RatedCore LossCurve Info

CoreLossSetup1 : Transient


Simplorer: Drive Design

1. Create Permanent Magnet Synchronous Machine Model from RMxprt:

Double click on the original RMxprt design, click on menu RMxprt > Analysis Setup > Export …,choose “Simplorer Model” from the list and select a path where you want the model to be saved.

2. View the text of the model: Run Simplorer V7.0.5, in “SSC 7.0 Commander” window, click on Programs > Editor, open the model file we just created from RMxprt(*.sml).

Note: The model is not simply a linear model you can typically find from a textbook any more. It has nonlinear effect considered for both main and leakage flux magnetic paths. This model can also be used as both motor and generator.



3. Use the RMxprt created model in Simplorer as a generator:

Open a new Simplorer Schematic, click on the “Add Ons” tab of the “ModelAgent”, click on “interfaces”, drag and drop “RMxprt” component on the schematic.

Double click on the “RMxprtLink1” and then click on “Import Model (*.sml)”, browse to the locationwhere the model was saved. Select the model > Open > OK, you should have the model show up like the following graph, with electrical nodes on the left and mechanical nodes on the right.



4. Build the rest of the schematic like below. Details of each component are shown on the next page.

RMXABC

ROT1ROT2

RMxprtLink1

ω+

V_ROT1

0

92.00

50.00

0 40.00m20.00m

DC Link Voltage

R_Load.V [V]

B6U

D1D3D5

D2D4D6

B6U1

R_Load C1

+ V VM1

-94.00

84.00

-50.00

0

50.00

0 40.00m20.00m

Back EMF (A-B

VM1.V [V]

0

2.00k

1.00k

0 40.00m20.00m

Input Speed from Shaft

V_ROT1.OMEGA [rpm]

-362.00

-3.55f

-300.00

-200.00

-100.00

0 40.00m20.00m

Rotor Position (Deg

RMxprtLink1.Pos

C := 1u

R := 1k

VALUE := 1000*(1+(t>0.02))



5. ModelAgent > Add Ons tab > power > Line-commutated Converters > B6 Diode Bridge



6. ModelAgent > Basics tab > Measurement > Electrical > Voltmeter

7. ModelAgent > Basics tab > Circuit > Passive Elements > Resistor and Capacitor

Note: Select the component and right mouse click to Flip or Rotate the component. Or you can use quick shortcut “F’ for Flip and “R” for Rotate.



8. ModelAgent > Basics tab > Physical Domains > Mechanical > Velocity-Force-Representation > Rotational_V > Angular Velocity Source



9. Click on Simulation > Parameters, or Alt + F12, or just double mouse click on any empty space on the schematic, define simulation parameters as seen from the picture.



10. ModelAgent > Displays tab > Displays > 2D View

Create plots of R_Load.V, VM1.V, RMxprtLink1.Pos, V_ROT1.OMEGA (rpm).

11. Run the simulation and view the results.


This completes the one day training course on permanent magnet

synchronous machines using Ansoft’sRMxprt, Maxwell 2D and Simplorer


Three-phase Induction Machine

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ing1

.Tor

que

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tPou

nds]

Ansoft Corporation 8_DesignSweepXY Plot 1

Curve InfoMoving1.Torque

Setup1 : TransientLengthFactor='1' Stator_ID='148mm' Volt_Mag='300V'

Moving1.TorqueSetup1 : TransientLengthFactor='1.2' Stator_ID='148mm' Volt_Mag='300V'

Moving1.TorqueSetup1 : TransientLengthFactor='1' Stator_ID='148mm' Volt_Mag='315V'






0.00 50.00 100.00 150.00 200.00Time [ms]

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1 [A

]

Ansoft Corporation 6_ModifiedWinding CurrentsCurve InfoCurrent(PhaseA)

Setup1 : TransientCurrent(PhaseB)

Setup1 : TransientCurrent(PhaseC)

Setup1 : Transient

0.00 5000.00 10000.00 15000.00RSpeed [rpm]

-10.00

0.00

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ienc

y [p

erce

nt]

Ansoft Corporation 3_FreqSweepXY Plot 2Curve InfoEfficiency

Setup1 : PerformanceScaleFactor='1'

EfficiencySetup1 : PerformanceScaleFactor='1.5'

EfficiencySetup1 : PerformanceScaleFactor='2'










EfficiencySetup1 : Performance


Contents

I. RMxprtBasic Theory

Main Features

Open and Run an Example and View Results

Modify the Design and View New Results

Create a Variable-Voltage Variable-Frequency Design

II. RMxprt -> Maxwell 2DCreate an Maxwell 2D Design from RMxprt

Review Maxwell 2D Transient Setup

III. Nominal Maxwell 2D DesignCreate an Maxwell 2D Design from RMxprt

Change Simulation Time Step

Set up Save Solution Fields

Set Eddy Effects for All Bars

Run Simulation and Review Quick Report

Measure Position Change of Each Time Step

Create Mesh/Field Plots and Animation

IV. Modifying Maxwell 2D DesignSet up Variable Simulation Time Step

Create output Variables for Stator Teeth and Stator Yoke Flux Densities

Change Angular Velocity

Set up Force Calculation

Multi-frequency Core Loss

Run Simulation and View New Results

V. Locked Rotor SimulationChange Initial Position and Angular Velocity

Change Bar Conductivity

Run Simulation and View Results

VI. Design SweepAdd Design Variables and Change Variable Values

Set up Parametric Sweep

Run Design Sweep and View Results

VII. Drive DesignCreate Induction Machine Model

Drive SimulationNotes:

1. RMxprt/Maxwell V12 or higher is required

2. Basic knowledge of electric machine is required

3. Basic understanding of Finite Element is required


I. RMxprt

Basic TheoryR1 X1 X2

RFe Xm R2/sU1

I1 I2

11

1

ImUP

=ϕcossRI3P 22

2m = 222 TP ω=fwm2 TTT −=

%100PP

1

2 ×=ηs1CuFe2Cufw21 PPPPPPP +++++=ωm

mPT =

Main Features

Optimization of Winding and Coil Arrangement

Winding Editor Supporting Any Single- and Double-Layer Windings

More than 20 Slot Shapes for Single and Double Squirrel-Cage RotorPear type with round shoulder

Pear type with tapered shoulder

Trapezoid type with tapered shoulder

Trapezoid type with round shoulder

Nonlinear and Distributed Parameters at Any Operation Condition


I. RMxprt

Open and Run an Example and Review Results

1. Menu item File > Open:…\Ansoft\Maxwell12\Examples\RMxprt\indm3\yzd132-4

2. Save As to your preferred location and name, for example: “IM3_Calss”Change RMxprt Design name from “yzd132-4” to “1_Original”

3. Run simulation and view results


I. RMxprt

Modify the Design and View New Results

1. Copy the design “1_Orginal” and paste into the project, change the new design nameto “2_RectWire”

2. Change the stator winding slot and wire to rectangular wire

3. Run simulation and view results


I. RMxprt

Create a Variable-Voltage Variable-Frequency Design

1. Create three new design variables: ScaleFactor, FreqSweep and VoltSweep, click onmenu item RMxprt > Design Properties

2. Assign VoltSweep and FreqSweepto Rated Voltage and Frequencyrespectively


I. RMxprt

3. Create a Parametric sweep


I. RMxprt

4. Run parametric sweep and view results: torque vs. speed

0.00 5000.00 10000.00 15000.00RSpeed [rpm]

0.00

10000.00

20000.00

30000.00

40000.00

50000.00

60000.00

70000.00

80000.00

90000.00

Out

putT

orqu

e [F

ootP

ound

s]

Ansoft Corporation 3_FreqSweepXY Plot 1Curve InfoOutputTorque


OutputTorqueSetup1 : PerformanceScaleFactor='1.5'

OutputTorqueSetup1 : PerformanceScaleFactor='2'










OutputTorqueSetup1 : Performance


I. RMxprt

5. View results: efficiency vs. speed

0.00 5000.00 10000.00 15000.00RSpeed [rpm]

-10.00

0.00

10.00

20.00

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ienc

y [p

erce

nt]

Ansoft Corporation 3_FreqSweepXY Plot 2Curve InfoEfficiency













EfficiencySetup1 : Performance


II. RMxprt -> Maxwell 2D

Create a Maxwell 2D Design from RMxprt

1. Create Maxwell design 2. Change the new Maxwell 2D design name to “4_Nominal”


II. RMxprt -> Maxwell 2D

2. Review Maxwell 2D setups

Geometry

Materials

Motion setup

Boundaries

Excitations

Mesh operations

Solve setup

Result plots

Ready to solve!Click on menu bar Maxwell 2D > Analyze All


III. Nominal Maxwell 2D Design

1. Right mouse click on Setup1 under Design 1_Original > Analysis > Create Maxwell Design

2. Change design name to “5_Nominal2”



3. Change simulation time step to 0.001s3. Change simulation time step to 0.001s 4. Add Save Fields 5. Run simulation ……



6. View results: Output Torque vs. Timeand Phase Currents vs. Time

7. Review other Quick Reports

0.00 50.00 100.00 150.00 200.00Time [ms]

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ing1

.Tor

que

[Foo

tPou

nds]

Ansoft Corporation 5_Norminal2TorqueCurve InfoMoving1.Torque

Setup1 : Transient

0.00 50.00 100.00 150.00 200.00Time [ms]

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-200.00

-100.00

0.00

100.00

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300.00

Y1 [A

]

Ansoft Corporation 5_Norminal2Winding CurrentsCurve InfoCurrent(PhaseA)



Setup1 : Transient



8. Add Position vs. Time plot

9. Change Trace Type to “Discrete”

10. Add Delta Marker tomeasure position changeof each simulation time step,it is 8.7767 deg



11. Plot mesh: CTRL+A to select all objects > right mouse click > Plot Mesh

12. Menu bar View > Grid Setting, turn Grid invisible14. Double click on bottom left corner to changeat what time step you want to view the plot13. Menu bar View > Coordinate System > Hide



15. Plot fields: CTRL+A to select all objects > right mouse click > Fields > A/H/B etc.

16. Right mouse click on the picture > Copy Image, try paste into Microsoft Word or Power Point

17. Uncheck Plot Visibilityto avoid all plots on top ofeach other



18. Create animation: right mouse click on the item under Field Overlays > Animate

19. Export the animation to .avi or .gif format and import into Power Point for presentation


IV. Modifying Maxwell 2D Design

Set up a Variable Simulation Time Step

1. Copy Design 5, paste and change name to “6_Modified”

2. Click on menu bar Maxwell 2D > Design Datasets

3. Add and edit design dataset “Time_Step”

4. Double click “Setup1” under “Analysis”,change Time step to “pwlx(Time_Step, time)”



Change Angular Velocity

1. Double click on MotionSetup1 underModel, click on “Mechanical” tabin the Motion Setup window

2. Change Angular Velocity to 1350 rpm

3. Check “Consider Mechanical Transient if you want to simulate mechanical transient



Set up Force Calculation

1. Select object “Bar” > right mouse click> Assign Parameters > Force

2. There is no need to assign Torque calculation,moving torque is assigned automatically in Transient Solver with rotational motion

3. You can assign as many Force calculations asyou may need. This is different from V11 2D, wherethe Force calculation is “hidden” in Transient andyou can only calculate one force at a time



Create Output Variables for Stator Teeth and Stator Yoke Flux Densities

1. Zoom in stator tooth and yoke area, drawtwo lines called “Stator_Tooth” and“Stator_Yoke”

2. Pay attention to use “Snap to” feature,like to vertex, to center point, etc.

3. In the next few steps we will use “Calculator” to create “Named Expression”: “Stator_Tooth_Flux” and “Stator_Yoke_Flux”

4. Click on menu item Maxwell 2D > Fields > Calculator



5. Quantity > B, Mag, Geometry > Line> Stator_Tooth, integration, Number,

0.25 (stator stack length in meters), *

6. Add, Stator_Tooth_Flux

7. Do the same for “Stator_Yoke_Flux”




1. Select both Rotor and Stator, click on material M19_24G_SF0.920 button in the Properties window

2. Click on Clone Material(s), change material name and Electrical Steel as Core Loss Type




3. Type in Mass Density = 7650kg/m^3

4. Click on Calculate Properties for> Core Loss versus Frequency




50Hz 100Hz

200Hz

400Hz



Run Simulation and View New Results

1. Run simulation

2. View existing plots: torque, current, position vs. time, compare with results from Design 5

0.00 50.00 100.00 150.00 200.00Time [ms]

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Mov

ing1

.Pos

ition

[deg

]

Ansoft Corporation 6_ModifiedPosition Quick Report

m1m2

Curve InfoMoving1.Position

Setup1 : Transient

Name X Ym1 44.0000 356.4000m2 45.0000 364.5000

Name Delta(X) Delta(Y) Slope(Y) InvSlope(Y)d(m1,m2) 1.0000 8.1000 8.1000 0.1235

0.00 50.00 100.00 150.00 200.00Time [ms]

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ing1

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que

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Ansoft Corporation 6_ModifiedTorqueCurve InfoMoving1.Torque

Setup1 : Transient

0.00 50.00 100.00 150.00 200.00Time [ms]

-300.00

-200.00

-100.00

0.00

100.00

200.00

300.00

Y1 [A

]

Ansoft Corporation 6_ModifiedWinding CurrentsCurve InfoCurrent(PhaseA)



Setup1 : Transient



0.00 50.00 100.00 150.00 200.00Time [ms]

0.000

0.001

0.002

0.003

0.004

0.005

0.006

0.007

Y1

Ansoft Corporation 6_ModifiedXY Plot 1Curve Info

Stator_Tooth_FluxSetup1 : Transient

Stator_Yoke_FluxSetup1 : Transient

3. Create Stator tooth/yoke flux density plots

4. Right mouse click on Results >Create Fields Report > Rectangular Plot



6. Create Core Loss vs. Time plot5. Create Force vs. Position plot

0.00 200.00 400.00 600.00 800.00 1000.00 1200.00 1400.00 1600.00 1800.00Moving1.Position [deg]

-1000.00

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0.00

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Y1 [n

ewto

n]

Ansoft Corporation 6_ModifiedForce_BarCurve Info

Force_Bar.Force_magSetup1 : Transient

Force_Bar.Force_xSetup1 : Transient

Force_Bar.Force_ySetup1 : Transient

0.00 50.00 100.00 150.00 200.00Time [ms]

0.00

10.00

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80.00

Cor

eLos

s [W

]

Ansoft Corporation 6_ModifiedXY Plot 3Curve Info

CoreLossSetup1 : Transient


V. Locked Rotor Simulation

1. Copy Design 6, paste and change name to “7_LockedRotor”

2. Double click on MotionSetup1 and change InitialPosition and Angular Velocity


V. Locked Rotor Simulation

3. Change Bar Conductivity to Simulate High Temperature Effect, use “cast_aluminum_75C”

4. Run Simulation and View Results

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ing1

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que

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Ansoft Corporation 7_LockedRotorTorqueCurve InfoMoving1.Torque

Setup1 : Transient

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Ansoft Corporation 7_LockedRotorWinding CurrentsCurve InfoCurrent(PhaseA)



Setup1 : Transient


VI. Design Sweep

1. Copy Design 6 and paste into the project, change design name to “8_DesignSweep”Variables

2. Right mouse click on the name of the design> Design Properties, add “LengthFactor = 1.2”


VI. Design Sweep

3. Click menu bar Maxwell 2D > Design Settings, change Model Depth

4. Click on PhaseA and change Resistance

5. Do the same for PhaseB and PhaseC resistance


VI. Design Sweep

6. Click on PhaseA and replace voltage with “Volt_Mag” > Enter > with default value 315V

315V

7. Do the same for PhaseB and PhaseC voltage


VI. Design Sweep

8. Click on CreateUserDefinedPart under Stator, change DiaGap in the Properties window to “Stator_ID”

9. Change the default value to 150mm


VI. Design Sweep

10. Right mouse click on Optimetrics > Add > Parametric


VI. Design Sweep

11. Right mouse click on Optimetrics > ParametricSetup1 > Analyze

12. View Results : right mouse click on Results> Create Transient Report > Rectangular Report

0.00 50.00 100.00 150.00 200.00Time [ms]

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que

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Ansoft Corporation 8_DesignSweepXY Plot 1

Curve InfoMoving1.Torque

Setup1 : TransientLengthFactor='1' Stator_ID='148mm' Volt_Mag='300V'









VII. Drive Design

1. Create Induction Machine Model from RMxprt:

Double click on the RMxprt design “1_Original”, click on menu RMxprt > Analysis Setup > Export …,choose “Simplorer Model” from the list and select a path where you want the model to be saved.

2. View the text of the model: Run Simplorer V7.0.5, in “SSC 7.0 Commander” window, click on Programs > Editor, open the model file we just created from RMxprt(*.sml).

Note: The model is not simply a linear model you can typically find from a textbook any more. It has nonlinear effect considered for both main and leakage flux magnetic paths. It also has eddy current effect considered for bars in order to more accurately model start-up performance of this machine.


VII. Drive Design

3. Use the RMxprt created model in Simplorer:

Open a new Simplorer Schematic, click on the “Add Ons” tab of the “ModelAgent”, click on “interfaces”, drag and drop “RMxprt” component on the schematic.

Double click on the “RMxprtLink1” and then click on “Import Model (*.sml)”, browse to the locationwhere the model was saved. Select the model > Open > OK, you should have the model show up like the following graph, with electrical nodes on the left and mechanical nodes on the right.


VII. Drive Design

4. Build the rest of the schematic like below. Details of each component are shown on the next page.

RMX

A

B

C

NRMX

A

B

C

N

RMxprtLink1

ROT1~

3PHAS

~

~

A * sin (2 * pi * f * t + PHI + phi_u)

PHI = 0°

PHI = -120°

PHI = -240°

THREE_PHASE1

-540.00

537.50

0

0 1.00500.00m

Line to Line Voltage VM1.V

T

MASS_ROT1FM_ROT1+

VVM1

ROT2

A

AM1

-208.00

251.00

0

0 1.00500.00m

Phase A Current AM1.I

0

1.52k

1.00k

0 1.00500.00m

Speed

MASS_ROT1.OMEGA [rpm]

-57.50

472.00

200.00

0 1.00500.00m

Torque FM_ROT1.TORQUE [Nm] STEP1.VAL

TLoadStepSTEP1

J := 0.2 kg m %

SIMPARAM1

990.00m

25.00

10.00

0 1.00

No. of Iterations

SIMPARAM1.Iterations


VII. Drive Design

5. ModelAgent > Add Ons tab > power > Power System and Cable Models > Ideal Three Phase Power Supply


VII. Drive Design

6. ModelAgent > Basics tab > Measurement > Electrical > Voltmeter and Ammeter

7. ModelAgent > Basics tab > Measurement > Mechanical > Velocity-Force-Representation > Torque Meter

Note: Select the component and right mouse click to Flip or Rotate the component. Or you can use quick shortcut “F’ for Flip and “R” for Rotate.


VII. Drive Design

8. ModelAgent > Basics tab > Blocks > Sources Block > Step Function


VII. Drive Design

9. ModelAgent > Basics tab > Physical Domains > Mechanical > Velocity-Force-Representation > Rotational_V > Mass


VII. Drive Design

10. ModelAgent > Basics tab > Physical Domains > Mechanical > Velocity-Force-Representation > Rotational_V > Torque Source


VII. Drive Design

11. ModelAgent > Basics > Tools > Simulator Parameters

12. Click on Simulation > Parameters, or Alt + F12, or just double mouse click on any empty space on the schematic, define simulation parameters as seen from the picture.


VII. Drive Design

13. ModelAgent > Displays tab > Displays > 2D View

Create plots of VM1.V, AM1.I, FM_ROT1.TORQUE, STEP1.VAL, MASS_ROT1.OMEGA (in rpm) and SIMPARAM1.Iterations.

14. Run the simulation and compare the results with RMxprt.


This completes the one day training course on Three-phase Induction Machine using Ansoft’s RMxprt,

Maxwell 2D and Simplorer

Ansoft Maxwell Field Simulator

Topic – Motor Application Note

Study of a Permanent Magnet Motor with MAXWELL 2D:

Example of the 2004 Prius IPM Motor



Study of an electrical machine

The Electro Mechanical software package provided by Ansoft enables extensive electrical malchinesimulation. This application note details the simulaton of an electrical machine with Maxwel2D. We will cover static and transient simulations. This application note will use the 2004 Toyota Prius motor as basis. It is a 8-pole permanent magnet motor with embedded magnets. The single layer windings are made of 3 phases. The stator has 48 slots. This motor is public, we therefore have the full set of parameters. We will also use Oak Ridge National Laboratory testing results in this note.

Note: This application has not been done with the collaboration of Toyota

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. WilesOak Ridge National Laboratory

Report on Toyota/Prius Motor Design and manufacturing AssessmentJ. S. Hsu, C. W. Ayers, C. L. CoomerOak Ridge National Laboratory

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



Overview of the Study:

GETTING STARTED

Creating the 3D Model

Reducing the size of the 3D Model

Material properties of the machine

Applying Master/Slave Boundary Condition

STATIC ANALYSIS

DYNAMIC ANALYSIS

COGGING TORQUE



Getting Started

Launching Maxwell1. To access Maxwell, click the Microsoft Start button, select

Programs>Ansoft>Maxwell 12.

Setting Tool Options

To set the tool options:

Note: In order to follow the steps outlined in this example, verify that the following tool options are set :

1. Select the menu item Tools > Options > Maxwell 2D Options2. Maxwell Options Window:

1. Click the General Options tab

Use Wizards for data entry when creating new boundaries: Checked

Duplicate boundaries with geometry: Checked

2. Click the OK button

3. Select the menu item Tools > Options > Modeler Options.4. 3D Modeler Options Window:

1. Click the Operation tab

Automatically cover closed polylines: Checked

2. Click the Drawing tab

Edit property of new primitives: Checked

3. Click the OK button



Opening a New ProjectTo open a new project:

1. In an Maxwell window, click the icon on the Standard toolbar, or select the menu item File > New.

2. Right mouse click on the project name, then select the menu itemRename. Change the project name to Prius

3. Select the menu item Project > Insert Maxwell Design, or click on the icon

4. Right mouse click on Maxwelldesign1 and select Rename. Change the name to 1_Whole_Motor

Set Model UnitsSelect the menu item 3D Modeler > Units. Select Units: mm (millimeters)



Creating the 2D Model

Maxwell has number of User Defined Primitives for motor parts. These primitives can describe all the main parts of motors.

Create the Stator: A User Defined Primitive will be used to create the stator

Select the menu item Draw > User Defined Primitive > Syslib > Rmxprt > SlotCoreUse the values given in the panel below to create the stator



Creating the 2D Model (Continued)

Click on the just created object in the drawing window and in the panel on the left change its name from SlotCore1 to StatorNote: the material will be applied afterwards

Create the Rotor

A User Defined Primitive will be used to create the rotor

Select the menu item Draw > User Defined Primitive > Syslib > Rmxprt > IPMCoreUse the values given in the panel next page to create the rotor




Click on the just created object in the drawing window and in the panel on the left change its name from IPMCore1 to Rotor

Create the Magnets

The same User Defined Primitive can be used to create the magnets, but with different parameters. UDPs can be computed to generate different topologies.

Select the object Rotor. Copy and paste the object using the Ctrl+C, Ctrl+Vcommands. An object Rotor1 is created




On the modeler tree, double click on the command ‘CreateUserDefinedPart’ of the object Rotor1

Change the InfoCore line from 0 (Core) to 1 (Magnets)

Change the name of the object from Rotor1 to MagnetsChange the magnets color from default to a light red.




Create the Windings

An User Defined Primitive will also be used to create the windings.

Select the menu item Draw > User Defined Primitive > Syslib > Rmxprt > LapCoilUse the values given in the panel below to create the coil

Change the Material from vacuum to Copper

Select the object LapCoil1, change its color to yellow




Select the object LapCoil1, and to apply a rotation of 7.5 deg along the Z axis, right mouse click, and select the menu item Edit > Arrange > Rotate or use the icon.

Select the object LapCoil1. This coil constitutes the first coil of Phase A. We now duplicate this coil to create the first coils of Phase C and B. Right Mouse click, and select the menu item Edit > Duplicate > Around Axis or use the icon.

Change the Name of objects LapCoil1_1 and LapCoil1_2 to PhaseC and PhaseB. Change the color of PhaseC to dark green and the color of PhaseB to light blue. Rename Lapcoil1 to PhaseA.




Select the objects PhaseA, PhaseB and PhaseC. Right Mouse click, and select the menu item Edit > Duplicate > Around Axis or use the icon. Enter 45degrees and 8 for the total number. This will create all the required coils.




The geometry of the motor is completed.

Depending on the solver and the motor performance data that we want to look at, we might have to add more objects (for meshing or movement setting). Save the project. Click on the Maxwell design ‘1_Whole_motor’, right mouse click and select ‘Copy’.

Click on the project name, right mouse click and select ‘Paste’. Change the copied design to 2_Partial_motor. We can take advantage of the topology of the motor to reduce the size of the problem. This motor has 8 pair of poles. We can only use one height of the motor. This is valid because the stator has:

48 slots (8 is a divider of 48). The 3-phase winding has also a periodicity of 45 degrees.

From now on, the Maxwelldesign ‘2_Partial_motor’ will be used. We have saved a copy of the whole geometry as it will be used later for other studies.



Reducing the size of the 2D Model (Continued)

Select all the objects from the modeler tree (or you can use the ctrl-A command). Right mouse click and select Edit > Boolean > Split or use the toolbar icon . Select the XZ plane and keep the positive side.

Note: During the process, a lot of messages will appear in the dialog box. These messages inform that some objects no longer exist as they entirely lie outside the remaining model.

We obtain half of the motor. Maintain the objects selected, right mouse click and select Edit > Arrange > Rotate or select the toolbar icon . Enter -45 deg for the rotation around the Z axis.

Maintain the objects selected, Right mouse click and select Edit > Boolean > Split or use the toolbar icon . Select the XZ plane and keep the negative side.

Maintain the objects selected, right mouse click and select Edit > Arrange > Rotate or select the toolbar icon . Enter 45 deg for the rotation around the Zaxis




The 3D model now looks like below

Rename PhaseA to PhaseA1 and PhaseA_7 to PhaseA2. Rename PhaseB, PhaseB_7, PhaseC and PhaseC_7 to PhaseB1, PhaseB2, PhaseC1 and PhaseC2.We can now create the Region around the motor. Most of the flux is concentrated within the motor, so we do not need to have a large Region.

Select Draw > Line1. Using the coordinate entry field, enter the box position

X: 0.0, Y: 0.0, Z: 0.0, Press the Enter key2. Using the coordinate entry field, enter the relative size of the box

dX: 200.0, dY: 0.0, dZ: 0.0, Press the Enter key3. Click Enter a second time to finish the drawing




Select Polyline1. Right mouse click and select Edit > Sweep > Around Axis.

Enter the parameters as specified in the panel below:

Rename the Region from Polyline1 to Region. Make sure that Vacuum is the selected material. Also, you might want to modify the render of the Region by increasing the transparency.



Material properties of the motor

Permanent Magnets characterization.

The Prius Permanent Magnets (PMs) are high-strength magnets.

In order to define PMs magnetization orientation, we need to create separate objects for each magnet. Select the object Magnets. Right mouse click, select Edit > Boolean > Separate Bodies. Rename the objects from Magnets to PM1and from Magnets_Separate1 to PM2.

Since the magnets will rotate, the orientation cannot be given through fixed coordinate systems (CS). The use of face CS is required. Face CS are CS that are attached to the face of an object. When the object moves, the Face CS also moves along with the object.

The Prius’s PMs are oriented as shown below. Therefore, we will create a face CS for each magnet.

Switch the select mode from Object to Face by clicking on the ‘f’ button or by using the toolbar icon:



Material properties of the motor (Continued)

Select the face of the magnet PM1 as shown below

To create the face CS attached to this face:

1. Select the menu item 3D Modeler > Coordinate System > Create > Face CSor select the toolbar icon

2. The modeler is in draw mode. It expects the center of the face CS that has to be on the selected plane to be selected. Snap the mouse pointer to one of the corner of the face, using the “snap to vertex symbol”” . This defines the CS center.

3. You need to enter the direction of the X axis. Snap the mouse point at another vertex of the face as shown below



Material properties of the motor (Continued)The face CS is created. Its default name is FaceCS1. Change its name from FaceCS1 to PM1_CS.

Repeat the same operation to create the face CS PM2_CS attached to PM2. Make sure to have the X axis looking toward the air gap

Reset the working CS to the Global CS by clicking on Global as shown below.




Edit the attributes of the object PM1. Modify the Orientation of the object by selecting the PM1_CS coordinate system. This CS will be the reference for the magnetization direction.

To enter into the material database, click on the Material button (the default material is Vacuum). The Prius magnet is not part of the default library, so clickon the Add material button




We have a special menu to enter Permanent Magnet parameters. At the bottom of the View/Edit material window, select the “Permanent Magnet” entry.

Enter the values given below to define the magnet strength




Change the material name to N36Z_20.

If the coordinate system PM1_CS is such that the X axis goes in the opposite direction of the air gap accordingly to the image below, leave the X orientation to 1 and 0 for the Y and Z components. If the X axis was in the opposite direction, you would need to enter -1 for the X component.

Click on the Validate button before closing the window to check the material definition.

Edit the attributes of the object PM2. Modify the Orientation of the object by selecting the PM2_CS coordinate system. This CS will be the reference for the magnetization direction. If the definition of PM2_CS is consistent with PM1_CS ( X axis in the direction of the air gap), you can use the same material for N36Z_20 for PM2. If it is not the case, you can clone the material N36Z_20 and change the orientation to be consistent with the PM2_CS axis.




Steel definition

The stator and rotor shares the same material. Select the objects Stator and Rotor. Edit their attributes, change the affected material. In the material database, add a new material called M19_29G.The steel is non linear. To enter the non-linear B-H Characteristic, change the Relative Permeability from “Simple” to “Nonlinear”

Click on the BH curve button in the Value column. The BH curve entry window appears




Enter the B-H characteristics with the values given below

H B0 0

22.28 0.0525.46 0.131.83 0.1547.74 0.3663.66 0.5479.57 0.65159.15 0.99318.3 1.2477.46 1.28636.61 1.33795.77 1.361591.5 1.443183 1.52

4774.6 1.586366.1 1.637957.7 1.6715915 1.831830 1.9111407 2190984 2.1350138 2.3509252 2.5

560177.2 2.5639944941527756 3.779889874




We neglect the Eddy current in this example, therefore we leave the conductivity to 0.

Validate the material before exiting the View/Edit material window

Make sure that M19_29G is affected to the Rotor and Stator.



Coreloss

This section is only necessary if you wish to compute the coreloss of the motor.

In the Transient solver, we are able to compute coreloss (or hystereris loss), stranded loss and eddy current loss (or proximity loss). We will only consider coreloss in this document.

We need to enter the loss values of the steel. A dedicated menu enables the user to enter the data.

Extend the project tree, and double click the Material definition of the Steel M19_29G

Use the pull down menu to enable core loss for Electrical Steel material



Coreloss (Continued)

The Maxwell solver requires the coefficients Kh, Kc, Ke and Kdc. A special menu allows the coefficients to be derived from manufacturer core loss data

Select at the bottom of the material definition window from the pull down menu Core Loss versus Frequency

The Core Loss versus Frequency menu pops up. We provide the data for several frequencies:

1. Select W/kg for the Core Loss Unit

2. Enter 7872 kg/m3 for the Mass density of the Steel

3. Enter 50 Hz in the Edit window

4. Click on Add5. Click on Edit Dataset in the Frequency Window


Topic – Motor Application NoteR Coreloss (Continued)

Enter the loss curve at 50 Hz:

Accept the setting

Using the same method enter the loss curves for 100, 200, 400, 1000 Hz

50 HzB P0 0

0.1 0.030.2 0.070.3 0.130.4 0.220.5 0.310.6 0.430.7 0.540.8 0.680.9 0.83

1 1.011.1 1.21.2 1.421.3 1.71.4 2.121.5 2.471.6 2.81.7 3.051.8 3.25

100Hz 200Hz 400Hz 1000HzB P B P B P B P

0 0 0 0 0 0 0 00.1 0.04 0.1 0.09 0.1 0.21 0.1 0.990.2 0.16 0.2 0.37 0.2 0.92 0.2 3.670.3 0.34 0.3 0.79 0.3 1.99 0.3 7.630.4 0.55 0.4 1.31 0.4 3.33 0.4 12.70.5 0.8 0.5 1.91 0.5 4.94 0.5 18.90.6 1.08 0.6 2.61 0.6 6.84 0.6 26.40.7 1.38 0.7 3.39 0.7 9 0.7 35.40.8 1.73 0.8 4.26 0.8 11.4 0.8 460.9 2.1 0.9 5.23 0.9 14.2 0.9 58.4

1 2.51 1 6.3 1 17.3 1 731.1 2.98 1.1 7.51 1.1 20.9 1.1 90.11.2 3.51 1.2 8.88 1.2 24.91.3 4.15 1.3 10.5 1.3 29.51.4 4.97 1.4 12.5 1.4 35.41.5 5.92 1.5 14.9 1.5 41.8



Coreloss (Continued)

The coreloss coefficient are automatically calculated

Accept the setting. The material definition now includes the coreloss coefficients



Applying Master/Slave Boundary Condition

The Master and Slave boundary condition takes advantage of the periodicity of the motor. Two planes are to be defined: the master and slave planes. The H-field at every point on the slave surface matches the (plus or minus) H-field at every point on the master surface.

Select the object Region from the active view. Right mouse click, then select View> Show In Active View as shown below

Change the Select mode to Edge

Select one of the bounding line of the Region



Applying Master/Slave Boundary Condition (Con’d)

Right mouse click, select Assign Boundary > Master

The vector u is defined correctly. Accept the setting.

Select the opposite edge of the Region


Topic – Motor Application NoteApplying Master/Slave Boundary Condition (Cont’d)

Right mouse click, select Assign Boundary > Slave

1. We first need to give the reference of the master condition. For the Master Boundary, since we haven't changed the default name, Select Master1

2. Select Swap direction for the u vector definition if the vector u does not have the same direction than the u vector of the Master condition.

3. The model represents one pole out of height. Since we represent an odd number of poles, the condition at the slave surface is Slave = -Master

4. Accept the set up



Applying Zero Vector Potential Boundary Condition

At the limit of the Region, select the five segments of the outside limit of the Region. Use the Ctrl button to allow multi selections

Right Mouse Click, Select Assign Boundary > Vector Potential

1. Put 0 Weber/m for the value

2. Name the condition Zero_Flux



STATIC ANALYSIS

We will study the different static parameters of the motor.

Save the project. Click on the Maxwell design ‘2_Partial_motor’, right mouse click and select ‘Copy’.

Click on the project name, right mouse click and select Paste. Change the copied design to ‘3_Partial_motor_MS’.

No Load Study

The first analysis that will be performed consists in computing the fields due to the permanent magnets.

The Coils are not needed in the model since no current is defined. Select the 6 coils. Then, Uncheck the radio button “Model” from the property window. Note that the Name of object line is empty since we have selected several objects.

Leave the Coils selected, and Hide the coils by selecting the menu item View > Hide Selection > Active view or using the toolbar button


Topic – Motor Application Notese

Apply Mesh Operations

The adaptive meshing is very effective, so it is not necessary to enter dedicated mesh operations. However, it is always a good idea to start with a decent initial mesh in order to reduce time computation since we know where the mesh needs to be refined for a motor. The non linear resolution will be faster with a small aspect ratios for the elements in the steel.Select the Rotor. Right Mouse Click and Select Assign Mesh Operation > Inside Selection > Length Based

Restrict the length of elements to 5 mm. Rename the mesh operation Rotor

Select the Stator. We want to minimize the number of elements for the curved line of the slots. Right Mouse Click and Select Assign Mesh Operation > Surface Approximation.

Input 30deg for the Maximum surface deviation Select 5 for the Maximum aspect Ratio.Rename the mesh operation SA_Stator



Apply Mesh Operations (Continued)

Select PM1 and PM2. Right Mouse Click and Select Assign Mesh Operation > Inside Selection > Length Based

Restrict the length of elements to 3 mm.

Rename the mesh operation Magnets

Apply Torque computation

Select the objects PM1, PM2 and Rotor. Right mouse click and select Assign Parameters > Torque



Add an Analysis Setup

From the project manager, right mouse click on Analysis and select Add Solution Setup:

1. Enter 10 for the maximum number of passes

2. Enter 0.1% for the error

3. In the convergence panel, enter 15% for the refinement

4. Make sure that the Non Residual is set to 0.0001%. Click Ok to record the analysis setup

Analyse

Right mouse click on the setup et select Analyze or click on the icon.



Post processing

The computation takes 7 passes to converge. The Convergence panel can be seen by right mouse clicking on Setup1, selecting the menu item Convergence

Torque value. Select the Solutions tab, the torque is given for a one meter depth motor. The torque for the full motor needs to be multiplied by 8 (symmetry factor), then by 0.082 (to account for the motor length). This gives 2.5mN.m, which sounds reasonable: the value is very small in regards to the full load operation. Different angles between the rotor and the stator would give different values.



Post Processing (Cont’d)

Plot magnetic flux density. Select the Rotor, Stator, PM1, PM2 right mouse click, select All Object Faces. Right mouse click again and select Fields > B > Mag_B. We obtain the distribution of B on the objects. The steel is highly saturated close to the magnets as expected. This saturations appears just because of the magnets strengths.

Plot the magnetic flux strength H in the air gap. We need to draw a post-processing line to view the field:

1. Draw an arc. Select the menu item Draw > Arc > Center Point or use the corresponding toolbar icon

2. Accept to continue to draw a non model object. This will not invalidate the existing solution

3. Enter the center of the arc: 0,0,0 mm and hit enter




4. Enter the first point of the arc. This point is at the middle of the air gap on the YZ plane. Enter 80.575, 0 , 0 mm and hit enter.

5. Enter the last point of the arc. This point lies on the plane XY, with a 45°angle with the X- axis. 80.575/ √2= 56.70996(…). Enter 56.70996, 56.70996, 0 mm and hit enter.

6. To finish the arc, move the mouse on the drawing area, right mouse click, and select the menu entry done

7. Name the polyline airgap_arc and accept the object




8. A new folder ‘Lines’ has appeared on the object tree, containing the new defined arc.

9. Select the line airgap_arc, move the mouse on the drawing area, right mouse click, then select the menu item Fields > H > H_vector.

10. Accept the Field plot setting




11. The vector plot of H appears with the default setting. To customize the display, double click on the scale zone:

12. You can modify the default settings in the different tabs like below:



Full Load Study

Save the project. Click on the Maxwell design ‘3_Partial_motor_MS’, right mouse click and select ‘Copy’.Click on the project name, right mouse click and select Paste. Change the copied design to ‘4_Partial_motor_MS2’. In this design, we apply current in the coils: we need to include the coils in the model. Select the 6 coils from the modeler tree. In the property window, select the radio button Model.

Unhide the coils by selecting the menu item View> Show selections> All views

Apply Excitations

The coils are partially represented in the model. We need to enter the current that flows in and out inside each coil. The excitation is realized through a balanced three phase system. For instance, in our example, we apply:

1500 A to PhaseA -750 A to PhaseB -750 A to PhaseC.

In the Magnetosatic solver, the sources are given in terms of currents. We do not need to model each turn at this stage; therefore we only enter the total current in each phase. The number of turns and the electrical topology are only taken into account for the inductances calculation.



Apply Excitations (Cont’d)

Switch the selection mode to face

Enter Excitation for Coil PhaseA2:

1. Select the PhaseA2

2. Right mouse click, select the menu item Apply Excitation > Current3. Rename the Excitation PhaseA24. Enter 1500A

5. As the default current direction plotted in red is good, leave Positive

6. Validate the Excitation





Enter Excitation for Coil PhaseA11. Select the PhaseA1

2. Right mouse click, select the menu item Apply Excitation > Current3. Rename the Excitation PhaseA14. Enter 1500A







Enter Excitation for Coil PhaseC21. Select the PhaseC2

2. Right mouse click, select the menu item Apply Excitation > Current3. Rename the Excitation PhaseC24. Enter -750A

5. As the default current direction plotted in red is not good, choose Negative






Enter Excitation for Coil PhaseC11. Select the PhaseC1

2. Right mouse click, select the menu item Apply Excitation > Current3. Rename the Excitation PhaseC14. Enter -750A

5. As the default current direction plotted in red is not good, choose Negative






Enter Excitation for Coil PhaseB21. Select the PhaseB2

2. Right mouse click, select the menu item Apply Excitation > Current3. Rename the Excitation PhaseB24. Enter -750A







Enter Excitation for Coil PhaseB11. Select the PhaseB1

2. Right mouse click, select the menu item Apply Excitation > Current3. Rename the Excitation PhaseB14. Enter -750A





Inductance computation

We are interested by the inductances computation. The source set up is independent from the winding arrangement: we have only entered the corresponding amp-turns for each terminal. When looking at the inductances, we obviously need to enter the number of turns for the coils and also how the coils are electrically organized.

Select Parameters in the project tree, right mouse click and select Assign > Matrix

Include the 6 phases in the matrix computation. The inductances are computed for 1 turn at this stage.

Select the Post Processing tab. We define in this panel the number of turns for each coil. Enter 9 for the six coils.

We also want to group all the coils of the same phase. This will enable us to have the inductance of the entire winding



Inductance computation (Cont’d)

Select the PhaseA1_in and PhaseA2_in entries, they hit the group button.Name The group PhaseA

Repeat the operation for the 3 phases

AnalyseRight mouse click on the setup et select Analyze or click on the icon.



Post processing

The computation takes 6 passes to converge. The Convergence panel can be seen by right mouse clicking on Setup1, selecting the menu item Convergence

Inductance values. Select the ‘Solutions’ tab. The inductance for each coils appears. It is assumed that each coil has only one turn.



Post processing (Cont’d)

Select the radio button Post Processed. The inductance for each winding is displayed

Note: it is possible to export the inductance matrix to Simplorer using the Export Circuit button

Torque value. Select the ‘Solutions’ tab, Select from the pull down menu Torque1. The torque for the full motor needs to be multiplied by 8 (symmetry factor), then multiplied by 0.083 (length of the motor). This gives around 47N.m. In this case, we have not synchronized the position of the rotor poles with the winding currents, so we are far from the optimized excitation value to obtain a maximum torque. Different angles between the rotor and the stator would give different values.




Plot the H field on the plane XY. Select the plane XY belonging to the global Coordinate System in the modeler tree

Move the mouse pointer to the drawing area, right mouse click and select the menu item Fields > H > H_vector

Validate the setting




With the default parameters, the H vectors are too small. Double click on the scale zone

On the ‘Color Map’ tab, uncheck the ‘Real time mode’ button and change the number of colors to 50

On the ‘Scale tab’ , Check the Use Limits button, then Enter 1 and 1e6 for the limits. Also, Check the Log button to have a log scale.




On the ‘Marker/Arrow’ tab, reduce the size of the arrow, then uncheck the Mapsize and Arrow tail buttons.

On the ‘Plots’ tab, make sure the right plot context is selected, then modify the Vector plot min and max to 1 and 5

We obtain the following plot. The H field is stronger around phase A as the input current is higher.



DYNAMIC ANALYSIS

We will study the transient characteristic of the motor.

Save the project. Click on the Maxwell design ‘2_Partial_motor’, right mouse click and select ‘Copy’.

Click on the project name, right mouse click and select Paste. Change the copied design to ‘5_Partial_motor_TR’.

Select the design name from the project manager, Right mouse click and change the solution type from Magnetostatic to Transient:



The transient solver acts differently from the Magnetostatic solver mainly because:

There is not adaptive meshing. Since the geometry changes at every time step, Maxwell does not re-mesh at every time step adaptively for obvious time reason. In transient analysis, we will build a good mesh valid for all the rotor positions.

The sources definition is different. In Magnetostatic, we were only interested in the total current flowing into conductor. In Transient, we use stranded conductors (the exact number of conductors is required for each winding) as the current can be an arbitrary time function. We need to create dedicated coils and windings.

Create Coils

Select the 6 coils PhaseA1, PhaseA2, PhaseB1, PhaseB2, PhaseC1 and PhaseC2.

Right mouse click and select the menu item Assign Excitation > Coil 1. Leave the default name as it will be automatically affected using the

object’s name

2. Enter 9 for the number of conductors



Create Coils (Cont’d)

The six coils definitions are processed.

We need to change the orientation of the coils for PhaseC1 and PhaseC2:

1. Select PhaseC1, in the Project Manager Tree

2. Right mouse click and select Properties

3. Switch the polarity from Positive to Negative

4. Repeat 1-3 with Coil PhaseC2



Motor excitation

The IPM motor is such that the rotor is in synchronism with the phase excitation. The excitation is such that the flux due to the permanent magnet is maximized in synchronization with the rotor movement.

The excitation is a 3 phase balanced current. The phase sequence is A+C-B+

At t=0, the A-phase has to be in the opposite axis to the d-axis. Therefore we have to move the initial position of the rotor by 30 deg such that the pole be aligned at the middle of A+A-

A+ A+

A-A-

B+

B+

B- B-C+

C+

A-A-

C- C-

B-

C+

C+

d-axis B-

30°

Maxwell model parts



Create Parameters for excitations

We need to define parameters that will be used to define the excitationSelect the menu item Maxwell 2D> Design PropertiesThe parameters window appearsClick on the Add button to add the number of poles of the motor

Enter Poles in the name area8 in the value areaClick on OK to accept the parameter

Using the same method enter:PolePair, the number of pair of poles; its value is Poles/2

Speed_rpm, the speed of the motor in rpm; its value is 3000Omega, the pulsation of the excitation in degrees/s; its value is 360*Speed_rpm*Polepair/60Omega_rad the pulsation in rad/s; its value is Omega * pi / 180Thet _deg the load angle of the motor ; for instance, we use 20 degrees in this study; enter 20 deg. Thet is load angle in radian therefore its value is Thet_deg * pi /180Imax the peak winding current of the motor; its value is 250A.



Create Parameters for excitations (Cont’d)

The design properties panel will eventually look like:

Create Windings

The terminals are meant to define the excitation paths in and out of the model. The actual excitation is defined through the definition of windings. A winding needs to be defined for each parallel electrical excitation of the motor.

The motor is excited with a balanced three phase connection. A sinusoidal excitation is applied. At each time step, the phases have a 120 degree shift. The load angle is also added.



Create Windings (Cont’d)

Winding PhaseA.. From the project tree, right mouse click on Excitations, then select the menu item Add Winding

1. Enter PhaseA for the name.

2. Select Stranded because each terminal has 9 turns

3. Enter winding current: Imax*sin(Omega_rad*Time+Thet). Time is the internal reserved variable for the current time.

4. Click on OK

5. Right mouse click on the winding PhaseA from the project tree, select the menu item Add Coils

6. Select the 2 PhaseA coils (using the Ctrl button) and click on OK



Create Windings (Cont’d)

Winding PhaseB.. From the project tree, right mouse click on Excitations, then select the menu item Add Winding. Repeat the same operation using :

Name the Winding PhaseBThe winding current is Imax*sin(Omega_rad*Time-2*pi/3+Thet). It is shift by -120 degrees from PhaseA.

Select the 2 PhaseB t coils

Winding PhaseC.. From the project tree, right mouse click on Excitations, then select the menu item Add Winding. Repeat the same operation using :

Name the Winding PhaseCThe winding current is Imax*sin(Omega_rad*Time+2*pi/3+Thet). It is shift by +120 degrees from PhaseA.

Select the 2 PhaseC coils

The project tree should now have the terminals sorted under each Winding:



Add Coreloss computation

The coreloss are not activated by default. If you wish to have them considered, expand the project tree window, right mouse click on Excitations> Set Core Loss

Select the steel objects: Stator, Rotor, Rotor2 and Rotor3

Accept the Setting

Note: you need to have the coreloss parameters defined in the material setup



Add Band object

The moving parts (rotor and permanent magnets) need to be enclosed in an air object, the band. This will separated the moving part from the fixed part of the project. Some rules apply for the definition of the band object for motor applications:

The band object must be somewhat larger than the rotating parts in all directions (except at the boundaries)

The band object should be a facetted type cylinder of wedge

It is very advisable to have an air object that encloses all the moving object inside the band object. This will facilitate the mesh handling around the air gap

To create the Band object, we will clone the region and adapt the parameters:

1. Select the object Region, Right Mouse click, then Select Edit > Copy

2. Use the Ctrl+V key combinaison to paste the Region.

3. Change the name of the object from Region1 to Band4. Expand the history tree of the Object



Add Band object (Cont’d)

5. Double click on the CreateLine command. The rotor radius is 80.2mm. The inner diameter of the stator 80.95mm. We pick the middle for Band object . Enter 80.575,0,0 mm instead of 200,0,0 for Point2

6. Double Click on the Sweep AroundAxis command.

7. Change the Number of Segments from 5 to 45 so that each segment of the line covers one degree

8. Leave the material to Vacuum.



Add Band object (Cont’d)

We now create an object that enclosed the moving objects inside the Band. Select the Band object, right mouse click, the select the menu item Edit > Copy or use Ctrl-C.

Paste another copy of the Band object by right mouse clicking and selecting Edit > Paste or with the Ctrl-V. A new object Band1 has been added to the object list. Expand its history tree, then double click on the CreateLine command

Edit the Point2: Enter 80.4, 0, 0 mm

This operation resizes the object to strictly cover the rotor and the permanent magnets

Rename the Band1 object to Band_in

Note: We will assign the motion after the mesh operations because we will have to add objects dedicated to the meshing in the moving part



Mesh Operations

The transient solver does not use adaptive meshing because this would require to refine the mesh at every time steps, leading to very high computation time. Using Mesh operations, we will define a decent mesh for the full transient simulation.

The Rotor is designed to be highly saturated around the permanent magnets, close to the air gap. It is required to have a good mesh density around this area.

To achieve this requirement, we create a couple of objects inside the rotor, then mesh operations will be applied to these objects in order to have a nice mesh around the ducts.

Select the menu item Draw > Line or select the icon from the toolbar.

1. Enter 78.72,0 ,0 mm for the position of Point1 and hit Enter

2. Enter 80.2,0 ,0 mm for the position of Point2 and hit Enter twice

3. Name the line Rotor2

Highly saturated zones



Mesh Operations (Cont’d)

The line looks like below:

Select the Rotor2 object, right mouse click and select the menu item Edit > Sweep > Around Axis.

Enter the parameters as below. Note that The Rotor object has been created with an UDP which produces true surface, therefore our mesh object Rotor2 has to have true surfaces. As a consequence, we enter 0 for the number of segments.




Change the material property of Rotor2 to M19_29G. Also, assign some color and transparency.

Note: since Rotor2 is entirely inside Rotor, we do not need to apply Boolean operations.

Note: because of the finite number of pixels on the computer’s screen, true surfaces are represented as facetted surfaces. Also, for the same reason, the object Rotor2 seems to intersect with the ducts but this is not the case. You can modify the default visualization setting using: View > Visualization Setting

Repeat the same operation to create the object Rotor3:

1. Draw a line with dimensions:

2. Sweep the rectangle around Z axis

3. Change the material property to M19_29G




Select the six coils PhaseA1, PhaseA2, PhaseB1,PhaseB2, PhaseC1 and PhaseC2. Right mouse click, select Assign Mesh Operations > Inside Selection > Length Based.

1. Name the operation Coils2. Check the button Restrict Length of Elements

3. Enter 4mm4. Uncheck the button Restrict the Number of Elements

5. Validate

Select the permanent magnets PM1 and PM2. Right mouse click, select Assign Mesh Operations > Inside Selection > Length Based.

1. Name the operation PMs2. Check the button Restrict Length of Elements


5. Validate




Select the Rotor. Right mouse click, select Assign Mesh Operations > Inside Selection > Length Based.

1. Name the operation Rotor2. Check the button Restrict Length of Elements


5. Validate

Select the Stator. Right mouse click, select Assign Mesh Operations > Inside Selection > Length Based.

1. Name the operation Staor2. Check the button Restrict Length of Elements


5. Validate



Assign Movement

Select the Band object, right mouse click and select the menu item Assign Band

In the Type tab:

check the Rotate motion button

Make sure that the Global:Z axis is selected

Select the Positive direction

In the Data tab:

Enter 30 deg for the initial position. The initial position of this synchronous motor is such that the A phase is opposite to the d-axis.

A+

A-

d-axis

30°



Assign Movement (Cont’d)

In the Mechanical tab:

enter 3000 rpm for the speed.

Click OK to validate the setting of the Band object.

Right mouse click on Model in the Project tree, then select the menu item Set Symmetry Multiplier

Since we model 1/8th of the motor (our model spans on 45°), Enter 8. The force, torque will be rescaled to take into account the full model.

Select the Model Depth tab. Enter 83.82mm for the motor depth. All quantities will be automatically be rescaled to the correct size.

Accept the setting



Add an Analysis Setup

Right mouse click on Analysis in the Project tree and select Add Solution Setup:

1. On the General tab enter the stop time and the time step. At 3000 rpm, a revolution takes 20ms (3000 rpm means 50 revolutions per second or 1/50 s for one revolution) . To achieve reasonable accuracy, we want to have a time step every 1 or 2 degrees. In this study, to have faster results, we use a time step of 250 us; it corresponds to 4.5 degrees.

2. The total simulation time is set to 15ms3. On the Save Fields tab

Select Linear Step

For Start, put 10ms

For Stop, put 15ms

For Step Time, put 250us

Click on Replace List

4. In the Solver Tab, set the Non linear residual to 1e-6.



Solve the problem

The setup is completed. Check the project using the Validate button

Maxwell checks the geometry, excitation definitions, mesh operations and so one. The model is validated but some Warning is displayed in the message box:

Eddy effect are not taken into account in our design which is what we decided

Select the Analysis Setup1 in the project tree, right mouse click and select Analyse



Post Processing

The full simulation takes some minutes.The mesh size appears in the profile of simulation. To display the profile, select the Analysis Setup, right mouse click and select Mesh Statistics. The mesh statistics are available in the corresponding tab

Performance curves can be displayed during the simulation.

Torque versus Time. Select the menu item Results in the project tree, right mouse click, then select the menu item Create Quick Report

Choose TorqueThe Torque up to the current time is displayed. As the simulation continues, you can update the plots: right mouse click on the Torque Quick Report entry and select Update Report




At the end of the simulation the Torque looks like below

The LoadTorque (in red) is zero as we are in motor mode.

We can see that there are a lot of ripples in the Torque. The ratio between the torque and the torque ripples is almost 10 percent. This is due to the unique structure of the IPM motor (Internal Permanent Magnets). To limit the ripple, some manufacturers modify slightly the rotor shape around the magnets or add a second layer of internal magnets. Also the control strategy plays a big role into preventing the ripples.

The torque value is around 240 N.m. This value is compatible with measurement.

The peak torque for this motor is about 400 N.m

Flux linkage versus Time. Select the menu item Results in the project tree, right mouse click, then select the menu item Create TransientReport > Rectangular Plot.

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Ansoft Corporation 5_Partial_Motor_TRTorque Quick Report1

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Moving1.LoadTorqueSetup1 : Transient





To include the flux linkage for each coil:

1. Select Winding in the Category Column

2. Select FluxLinkage(PhaseA), FluxLinkage(PhaseB), FluxLinkage(PhaseC) in the Quantity column

3. Select New Report4. Select Close

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Ansoft Corporation 5_Partial_Motor_TRXY Plot 2Curve Info

FluxLinkage(PhaseA)Setup1 : Transient

FluxLinkage(PhaseB)Setup1 : Transient

FluxLinkage(PhaseC)Setup1 : Transient




Induce Voltage versus Time. Select the menu item Results in the project tree, right mouse click, then select the menu item Create TransientReport > Rectangular Plot.Use the same method to plot the Induced Voltage

The curves are not really smooth. The reason is that the time step is too high. As the induced voltage is a derived quantity, Maxwell needs to derive the total flux ; the time steps is way to high to have accurate Induced Voltage. If you re run the simulation with a time steps of 50us (instead of 250 us), the Induced Voltage will have a more realistic shape:

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Ansoft Corporation 5_Partial_Motor_TRXY Plot 1Curve Info




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Ansoft Corporation 5_Partial_Motor_TR_smallXY Plot 1Curve Info







Plot the Mesh. Select all the object, right mouse click and use the Plot Mesh button

Plot magnetic flux density.

1. Select the menu item View > Set Solution Context or double click on the “Time=-1” icon in the modeler window

2. Select the time 0.01s from the pull down menu




3. Select the Stator, Stator2, Stator3, PM1 and PM2 objects. Right mouse click and select Fields > B > Mag B

4. Accept the Setting

5. The B field at 0.01s is displayed.

6. Change the scale by double clicking on the Scale aera

7. Go to the Scale Tab and enter 0 for min and 2.2 for max

8. Close the Window




Plot magnetic flux density (Animation). It is possible to animate the fields. Select Maxwell2D > Fields > Animate.

Make sure that the sweep variable is Time

Select the time values

Accept the setting

The animation is displayed once the frames are calculated.

You can export the animation using the Export button from the animation button



Parametric Study

The setup that has been solved was with a load angle of 20 deg. If the load angle is modified, the simulation has to be restarted.

A parametric sweep of the load angle will therefore take a long time. We can propose two approaches:

Realize an Equivalent Circuit Extraction of the motor. This method requires the combination of parametric sweeps in magneto-static and the circuit simulator Simplorer. We will not discuss this method in this write-up.

Realize a parametric transient simulation. To cut the simulation time, the use of the Distributive Solve is necessary. This is the chosen method

Click on Optimetrics in the Project tree. Right mouse click and select the menu item Add > Parametric

The parametric setup panel appears



Parametric Study (Cont’d)

Select the Add button to include a design variable in the sweep

Select Thet_deg from the pull-down menu:

1. Enter 0 deg for the first value

2. Enter 60 deg for the last value

3. Enter 15 deg for the step

4. Push the Add button

Select the ‘Table’ tab, the parametric rows are displayed




Select the General’ Tab. This panel enables the user to change a design variable. For instance, if you wish to run the parametric sweep with a peak winding current of 400 A, select the Override button, and change the current value.

Select the Calculations Tab

1. Select the Setup Calculations button

2. Under the Category column, select Torque 3. Under the Quantity column, select Moving1.Torque4. select the Range Function button.

5. Select the Specified radio button

6. Setect the Math Category

7. Select avg in the Function pull down menu

8. Click on ok

9. Click on Add Calculation10. Click on Done




The sweep setup panel contains the desired quantity

In the Options tab, you can choose to save fields and meshs for all the variations

Accept the setup

Run the parametric sweep. To run the sweep, select the Parametricsetup1, right mouse click and select the menu item Analyse

Results. Right mouse click on Parametricsetup1, and select View Analysis Result

All the plots are now available for any variation



COGGING TORQUE

The Cogging Torque corresponds to the torque due to the shape of the teeth and the permanent magnets, when all the coils excitations are 0. The torque is a very small value in regard to the full load torque. Its computation is very sensitive to the mesh, as its value is in the same order of magnitude of the mesh noise.

To compute accurately the cogging Torque, one could solve a parametric sweep in Magnetostatic (the input parameter being the angle between rotor and stator). This method will not lead to excellent results as the error due to the mesh will be different for each position (the mesh will change for every row).

The preferred method is the use of the transient solver with motion:

We will move the rotor at the speed of 1 deg/s

The mesh will remain unchanged for all the positions thanks to the Band object : the mesh inside the Band object will rotate with the rotor

Each time step will be independent of the other

The adaptive mesh will not be used therefore the simulation time will be shorter

Save the project. Click on the Maxwell design ‘5_Partial_motor_TR’ , right mouse click and select ‘Copy’.

Click on the project name, right mouse click and select Paste. Change the copied design to ‘6_Partial_motor_CT



Creation of an air Object

We derive the set up for the cogging torque calculation from the Full load setup. We will change the speed, the excitations and some meshing operations.

Since the mesh has to be well defined in the air gap, we will add an object so that we have enough layers of element:

1. Copy and Paste the Object Band_in

2. Rename the object Band_in1 into Band_out.

3. Expand the history tree of Band_out and change the CreateLine command:

Replace 80.4 ,0 ,0 by 80.75 ,0 ,0 mm

This create a third layer in the air gap

Stator

Band_out

Band

Band_in

Rotor2

Rotor3

Rotor



Increase the segmentation of air objects

For the dynamic analysis, the ojects Band, Band_in had one segment every degre. In order to reduce mesh error, we reduce the span of each segment.

Expand the history tree of the objects Band, Band_in and Band_out:1. Double click on the SweepAroundAxis command of the Band object

2. Change the number of segments from 45 to 135 3. Repeat 1-2 for the objects Band_in, Band_out



Meshing Operations

We need to reassign the Band. Expand the project tree of the current design, and delete the MotionSetup1

Select the Object Band, right mouse click, and select Assign Band

Enter the following parameters for the Motion Setup

In the Type Tab, for Motion Type: Rotation around Z axisLeave the Data tab unchanged

In the Mechanical tab, enter 1 deg_per_sec Accept the Setting



Meshing Operations

We also need to change the meshing operations. The mesh density that was good enough to compute the full load torque won’t be accurate enough for the cogging torque

Expand the project tree, and under Mesh operations, edit the Meshing operations Rotor, Stator:

Change the maximum length from 4mm to 3mm

Select the objects Rotor, Rotor2, Rotor3 and Stator. Right mouse click and select Assign Mesh Operation > Surface Approximation

Name the meshing operation SA_Rotor_Stator

Set the minimum normal deviation to 1 deg

Ignore the other settings



Create the Analysis Setup

We can delete the coils as they are not needed in the cogging torque simulation

Select the 6 coils and delete them

Expand the analysis setup already defined and edit it:

One pole pair takes 7.5 mech degrees. We will solve over 15 s in order to have two periods (remember: the speed is 1 deg/s)

We set the time step to 0.125 s to have a very smooth curve. An higher time step is still valid if you want a faster result.

Lower the non linear residual to 1e-4.

Accept the Setting



Analyse

From the project tree, right mouse click on Setup1, and select Analyse.

It takes a couple of minutes to solve

From the project tree, right mouse click on Results, and select Create Transient Report > Rectangular plot. The Trace window pops up

From the Category column select TorqueFrom the Quantity column, select Moving1.TorqueSelect New ReportSelect Close

The Torque trace appears. As expected, the cogging torque is periodical. The peak value is about 1.75 N.m.

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Ansoft Corporation 6_Partial_Motor_CTCogging TorqueCurve Info


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Ansoft Maxwell v12 User Guide Machine Design Reference Guide

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Transcript of Ansoft Maxwell v12 User Guide Machine Design Reference Guide