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CADFEM 2017

Simulation of Electric Machines with ANSYS

Jens Otto CADFEM GmbH

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CADFEM 2017

Why Simulation with ANSYS ? Challenges for electric machines

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Electromagnetic Design:

Rated power/ Power-Volume-Ratio

Material consumption

Losses/Efficiency

Torque ripple

Circuit interaction

Structural Design:

Housing integrity

Active steel integrity

Winding-end design

Cooling Design

Air/Fluid flow

Coupled Analyses:

Temperature prediction

Vibroacoustics

CADFEM 2017

Simulation Driven Product Development Customer Workflow

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Marc Brck EM-motive a Bosch + Daimler Company

CADFEM 2017

Virtual Prototype: Simulation is Everywhere!

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Electromagnetic is just

one aspect of design

EADT also part of

Workbench environment

Thermal

Fluid-flow

Structural

Coupled Simulation

CADFEM 2017

Electromagnetic FEM Solution in ANYS Maxwell

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Maxwell:

Static

Time-Dependent

Time domain (Transient)

Frequency domain (Harmonic)

Motion (Linear, Rotational)

Advanced physics capability

2D; 2.5D; 3D

Materials

Circuit coupling

Source: CADFEM

CADFEM 2017

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Translate differential equation to

algebraic equations

Discretize space by

tetrahedrons/triangles

Quantities are interpolated between

nodes

Solution

computed

on nodes

Source:CADFEM

CADFEM 2017

Automatic Adaptive Meshing

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Generate efficient mesh without

expert mesh know-how

Find a compromise accuracy vs

simulation time

User defined convergence criteria

Global energy error (default)

Torque

Force

Inductance

Adaptive meshing available

for all non-transient solvers

Calculate local

Solution error

Generate Initial

Mesh

Solve fields using the

Finite Element Method

End criteria

reached ?

Refine Mesh

Calculate Outputs

(Force, Inductance, etc.)

no

yes

Start

CADFEM 2017

Automatic Adaptive Meshing Example

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Source ANSYS Inc.

CADFEM 2017

Mesh Operations

- 9 -

Can be combined with adaptive

approach

Fewer iterations

Faster solution times

Mesh refinement for transient

simulations

Manual mesh refinement

Import mesh from static/harmonic

Source CADFEM

CADFEM 2017

True Motion in Electromagnetic Simulation

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User friendly configuration

Velocity dependent effects

Eddy currents (effect on field)

PMs

Squirrel cage

Conducting slot wedges/

mechanical parts

External particles

CADFEM 2017

3D Vector Hysteresis Modeling

Lamination support

Optimization to minimize total error

of major & minor loop

Non-zero initial condition support

footer 11

CADFEM 2017

Material properties

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Nonlinear and/or anisotropic permeability

Anisotropic conductivity

Core loss model

Steinmetz approach

electrical steel

power ferrite

Solid or lamination model

Scaling of B-H curve

Temperature dependent

CADFEM 2017

User Friendly Extraction of Steinmetz Coefficients

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Select extraction method

Core loss versus frequency

Core loss at one frequency

Lamination thickness needed

Input datasheet data from supplier

Manual

csv, txt import

Sheet scan

Automatic calculation of coefficients

Automatic update in material properties

CADFEM 2017

Simulation Dimensionality

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2D Simulation

Planar B-field

General machine sizing

2.5D for skewing approximation

Stepwise approximation

3D

Full flexibility

Detailed eddy current paths

End effects (Stray fields)

Non planar flux

CADFEM 2017

Since R17: Time Decomposition Method

HPC-Method for transient magnetic

designs

Simultaneous calculation of k time

steps

N-Tasks containing k-time steps each

N-Tasks can be distibuted in DMP

mode

T1 Tk

k Time Steps

n Parallel

Distribued Tasks

Matrix Size

X k

T1

T2

T3

T(k-2)

T(k-1)

T(k)

Source: ANSYS Inc.