integrating fea into existing process flows

8/6/2019 Integrating FEA Into Existing Process Flows

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Integrating FEA into

Existing ProcessFlows for ElectricalMachine Design

Presenter: Scott StantonAnsoft Corporation

Contributing Author:Johannes Germishuizen

Siemens AG – Automation and Drives A&D LD TD2



MotivationDesire to improve existing process flow:

Due to the difficulties in obtaining accurateanalytical solutionsIterative process needed for transient FEA



Existing Process

Customer Requirements

Create Initial Design:- Transient FEA- Voltage Sources- Including Field Weakening- Iterate to obtain δ

Each iteration requires atransient solution

Torque (N-m)



Proposed Process


Create Initial Design.

Map of solution domainT , ψ d, ψ q = f(i d , i q,Θ )using Static Solver

Scale

N, L

ScaleN, L

TorqueCurrentVoltage



Proposed Process


Create Initial Design.

Map of solution domainT , ψ d, ψ q = f(i d , i q,Θ )using Static Solver

Scale

N, L

ScaleN, L

TorqueCurrentVoltage

Verify with Transient



User Defined GUI:Input Parameters

Stator Geometry

Materials

Rotor Geometry

Solution Range

Winding Definition



Maxwell Script: Model Setup

Create GeometryAssign MaterialsSet Boundaries and ExcitationTransform d, q to a , b, c

Setup Torque CalculationSetup Mesh Operations



Ansoft’s products communicate with any programthat utilizes COM (Common Object Module):

Ansoft Scripting Environment

MatlabExcel

Tcl/TkJava ScriptVisual Basic

Perl



Maxwell Project Setup

Nominal problem utilizesmesh operation and

Automatic Adaptive Meshing

The Parametric problem readsin the final adaptive mesh fromNominal problem, thus no re-meshing



Solution Domaind_min < d < d_max by ∆ dq

q_min < q < q_max by ∆ dq

Where: min, max and ∆ dq are user defined

+−+−−−

−=

0

*

1)120sin()120cos(

1)120sin()120cos(

1sincos

q

d

C

B

A

i

i

i

i

i

θ θ

θ θ

θ θ

( )( ) N iii

N iii N iii

qd C

qd B

qd A

*)120sin()120cos(

*)120sin()120cos(*)sincos(

+−+=

−−−=−=

θ θ

θ θ θ θ



Solution Domain

Solve

Sequentiallywithin Script Distributed SolveOption (DSO)

-900 < d < 900 : ∆50

-900 < q < 900 : ∆50

1296 variations

For stage 1 of the project, Θ = 0



Distributed Solve



DSO – Distributed Solve Option

……

Host

Nodes

6100 trianglesMesh size

5.3Speed-up factor

2 Hr 30 minReal time

Computation CharacteristicsNumber of Variations: 1296

Sequential Solve: 13 Hr 15 min

HP Cluster: 8 cpu’s

CPU type: Intel Xeon1.87 GHz2 Gig RAM/CPU

OS: Windows XP



Maxwell Script: Post Processing

Extract Torque ValueCalculate Flux LinkageCalculate Avg. Tooth Flux DensityCalculate the Normal Component of

the Flux Density in Stator Yoke

Used for Core Loss Calculation



Post Processing: TorqueOne of the advantages of using Maxwell is thetorque is calculated using the virtual workmethod:

As opposed to the analytical method:

•Θ

=Θ

Θ=

=v

H

const i BdV dH B

d

d

d

idW T

0))((|

),(

It’s difficult to obtain L d and L q analytically

qd qd m ii L L pT ))((23 −+= ψ



Post Processing: Torque



A,B,C Flux Linkage Calculation

Ω

Ω−Ω=Ψ

1

11_|11_|

1d

d Ad A e RaCoil zaCoil z

a

ckt SF aaaa A / *4321 Ψ+Ψ+Ψ+Ψ=Ψ

Where: SF = Symmetry Factorckts = number parallel circuits

… assuming four coils in solution domain



Maxwell Field Calculator



D-Q Flux Linkage

+−−−−+−

=

C

B

A

q

d

ψ

ψ

ψ

θ θ θ

θ θ θ

ψ

ψ

ψ

*

2

1

2

1

2

1)120sin()120sin(sin

)120cos()120cos(cos

*3

2

0

dq0 transformation:

Maxwell MatrixUser requirement



Permanent Magnet FluxSet d = q = 0 amps and calculate flux linkage of

the Phase A winding: ΨAm

Am A M Ψ−Ψ=Ψ

),(,,, qd qd M ii f T =ΨΨΨ



Output Quantities



Core LossAutomatically searchYoke and Tooth for themaximum value of B.

55

11 ÷

=

=n n

nmag

t dl

dl B B

•=

→

1

1

1dl

dl B B y



Core Loss

Calculate Core Loss:1st for B t_avg_max2nd for B ymax

Total Loss = P(B tmax )+ P(B ymax )*Mass



Calculate Performance CurvesSolution Domain:

(i d 1, i q 1), (i d 2, i q 2), . . . (i dn , i qn ) ) T = T 8

T* user required torque1. Find the minimum stator current:

i d | T =T 8

= f (i q ) a 1D interpolation to find I 1,min

2. With the pair ( i d , i q )| I 1= I min known, obtain d and q

3. Obtain u d and u q :

d qq

qd d

i Rui Ru

ωψ ω

−=−=

1

1

),(,, qd qd ii f T =ΨΨ



Calculate Performance Curves4. Calculate the line voltage, U 1.5. Test if U 1 exceeds the maximum allowable

voltage, i.e. U 1 < U max (DC bus voltage)

6. If U 1 > U max decrease i d until U 1 = U max .

7. Calculate Stator Current and Line Voltage( )

max1

22

1

22

1 2

3

2U U

uuU

ii I qd qd <

+=

+=

USER DEFINED PROCESS FLOW!



Output of User Defined ProcessFlow: Performance Curves

Maxwell solution domain: per turn and per lengthUser can change N and L to meet inverter requirements



Verification – Maxwell Transient



ConclusionsMaxwell easily plugs into existing process flowFull automationMagnetostatic solver can give reasonablefingerprint of motor performanceTransient is employed for verification

Proposed process flow greatly increases: Speed,Accuracy and Capacity over existing process flow.



Appendix: RMxprt Maxwell 2DAutomatic Generation of 2D Design



Appendix: RMxprt Maxwell 2D



Thank You

integrating fea into existing process flows

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