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© CADFEM 2017

Sicherheit und Innovation durch SimulationLucas Kostetzer, CADFEM GmbH

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Simulation for e-Mobility

• Motor Design• Motor Cooling• NVH (Noise Vibration Harshness)• Structural Dynamics• Power Electronics

© CADFEM 2017

• Power Electronics• Battery• Charging• EMC/EMI• System

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Simulation for e-Mobility

• 1. Motor Design• 2. Motor Cooling• 3. NVH (Noise Vibration Harshness)• Structural Dynamics• Power Electronics

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• Power Electronics• 4. Battery• 5. Charging• EMC/EMI• 6. System

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1. Motor Design: Motor-CAD SoftwareØ Application specific tool for design and simulation of

electric motors

Ø EMag: template driven 2D FEA combined with analytical equations for fast calculation of motors electromagnetic/electrical performance

Ø Therm: heat transfer and flow network circuits

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Ø Therm: heat transfer and flow network circuits automatically set up to give quick steady-state & transient thermal predictions

Ø Lab: Provides efficiency mapping, continuous & peak torque envelopes and duty cycle transient thermal analysis within seconds/minutes

1. Motor Design: Performance Prediction for Nissan LEAF Motor

Ø Using published teardown data for Nissan LEAF motor

Ø Developed models to validate & demonstrate software tools for modellingtraction applications

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1. Motor Design: Performance Prediction for Nissan LEAF Motor

Ø Predicted efficiency map validated by test data

Ø Thermal model validated by 50kW, 60kW,

Motor-LAB

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50kW, 60kW, 70kW, 80kW thermal transient test data

good match

Measured

1. Motor Design: Drive Cycle Prediction (Nissan LEAF)

Ø Prediction of efficiency map and 10 repetitive US06 Drive Cycle thermal transient in a few minutes

Torque vs time

Total Loss

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time

Speed vs time

Copper Loss

Iron Loss

1. Motor Design: Detailed Electromagnetic Analysis

• 3D Effects• Demagnetisation• Eddy Currents, Losses• Excentricity• Tolerances

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• Tolerances• Short Circuit, Faults• Inverter Induced Losses• Extraction of Reduced Order

Model, ECE

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2. Motor Cooling:

• Cooling• Extraction ROM, MOR, LTI• Transient Behaviour

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2. Motor Cooling: Modeling Water Jacket Cooling Channels

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Path LinesStatic Pressure

2. Motor Cooling: Modeling Water Jacket Cooling Channels

Distribution of coolant using different channel configurations

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Temperature Profile

2. Motor Cooling: Air Cooling

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Transient EM to calculate losses

Separate mesh for flow domain

EM loss data transferred and automatically mapped

Flows and temperatures in CFD

2. Motor Cooling: Thermal model for System Simulation

• Cooling of a electric motor with given losses

• Convective heat transport through the system due to water flow (or air, oil,…)

FEM to System

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• Model Reduction in ANSYS Mechanical with CADFEM MOR-ACT

• Validation of the created "system" in ANSYS Simplorer

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2. Motor Cooling: ANSYS Simplorer FullDutyCycle

• Separated analysis for Load Cycle (heat losses)• duration T=800s• peak value approx. 20kW

H

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [s]

0.00

10.00

20.00

H1.

H [k

W] Curve Info

H1.HTR

heat_generation_1

CASCON_Motor_ROM

NL

LoadCycle

GAIN

Shift

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• Thermal network with Reduced Order Model for the Motor

• Simulation time is about 1/1000 compared with 3D FEM • Kühlung ausreichend

• TMAX=13°C

0

THM1

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time [s]

273.15

283.15

293.15

303.15

310.00

THM

1.T

[kel

]

Curve InfoTHM1.T

TR

H

H1

NL GAIN

0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00 800.00Time

273.15

283.15

293.15

303.15

310.00

THM

1.T

[kel

]

270.00

280.00

290.00

300.00

310.00

Mec

hani

calT

empe

ratu

r

Curve InfoTHM1.T

TR

MechanicalTemperaturImported

3. NVH: General Concepts of Electric Drive Acoustics inside ANSYS

Origin of Noise by Electrical Drives:

Magnetic Circuit Fluidics

Cooling

Drive Side

Gearbox etc.Reluctance, geometry

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è Electric Drive Acoustics inside ANSYS

Gap forces

Magnetostriction

Inverter- synchronous pulse- asynchronous pulse

Current waveform

Magnetic saturation

Courtesy of Elektromotorenwerk Grünhain GmbH

3. NVH: Electric Drive Acoustics inside ANSYS

Workflow From Computation of Excitation Loads to ERP Postprocessing:

Electro-magnetic

Harmonic Vibration DFT

Oscillation,ERP,

External computation of excitation loads

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magnetic Analysis

Vibration Analysis

DFT ERP,Waterfall PlotExcitation

Loads

ERP = Equivalent Radiated Power

3. NVH: General Concepts of Electric Drive Acoustics inside ANSYS

Harmonic Analysis Based on Mode Superposition:

• Time and memory saving

• Eigenmodes and -frequenciesas intermediate result

ANSYS Project Structure:

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• Excitation loads will be imported into the harmonicanalysis using functions of Electric Drive Acousticsinside ANSYS.

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Mode 1 Mode 3 Mode 6610 Hz 1456 Hz 2654 Hz

Modal Analysis Harmon. Analysis

Excitations

3. NVH: General Concepts of Electric Drive Acoustics inside ANSYS

Data Processing: Load application always at Remote Points attached to faces!

Excitation spectra in frequency domain

Excitation loads in time domain, supplied by user

DFT

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Surface

Mode-SuperpositionHarmonic Analysis

(Sweep of Rot. Speed)

Computation ofERP-spectrum

Modal coordinates(.mcf-file)

3. NVH: General Concepts of Electric Drive Acoustics inside ANSYS

Concept of Interpolation of Excitations Through a Rotational Speed Range:

• Example:Supply excitations only for a few operatingpoints of the motor characteristics.

n1

n2n1 n2

Frad

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• After DFT: One excitation spectrumper force/moment component andoperating point.è Interpolation between OPs.

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n(sweep)

n2

n3

n4

n5

n1 n2

n3 n4 n5

Motor characteristics

Torq

ue

Speed

3. NVH: Vibration Function Overview

ERP-Visualization:

• ERP Spectrum(selected single speed point)

© CADFEM 2017

• ERP Waterfall (speed range)

• Watt or dB

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4. Battery: Challenges in battery pack design

• Minimize temperature differencesbetween cells and inside cells

• Guarantee an optimal temperature range

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• Balance cell usage• Resistance/Capacitance f(T)

• Operating conditions under control to avoid explosion / run-away

Thermal runaway of the battery for auxiliary power of a Japan Airlines 787Source: U.S. national Transportation Safety

4. Battery: Chalenges

• Multi-Scale Physics in Li+ Batterymaterial electrode pair cell, pack

Pos

itive

el

ectro

de

Neg

ativ

e el

ectro

de

Sep

arat

or

© CADFEM 2017

• Approaches in this presentation• Cell, pack : Field based• Pack and Vehicle integration: System based

10-6~10-4 10-2~10010-9~10-8

Pos

itive

el

ectro

de

Neg

ativ

e el

ectro

de

Sep

arat

or

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Length scale[m]

4. Battery: Equivalent Circuit Model (ECM)

© CADFEM 2017

• Circuit components• A)

• B)User Defined

• Coupling @ Cell level

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VolIj = ( ) ÷

øö

çèæ ---= -+ dT

dUTVVol

Iq OCVECh jj&

( )( )( )( ) 210

210

expexp

aSOCaaCaSOCaaR

ai

ai

+=+=

÷ø

öçè

æ=

÷ø

öçè

æ=

å

å

=

=

5

0

5

0

n

nni

n

nni

SoCaC

SoCaR

ECM: typical approach from OEM‘s!Circuit tables are derived fromstandard measurementsOR

Contour of φ-

4. Battery: Example: single battery cell

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Contour of φ-

Temperature

Cylindrical cell with discrete tabsPrismatic cell 25

4. Battery: 1P20S with air cooling channel

Velocity field

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Total heat generation rate

Temperature profile26

4. Battery: Module Level – CFD Thermal - Optimization

Initial Optimized

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Velocity Distribution

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Velocity Distribution

4. Battery: System based battery simulation

• How about current load conditions and the design of thermal management control?>System simulation

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• How to use detailed FIELD models/results to improve System modeling ?>ROM ( Reduce Order Model ) + System Simulation

Drive cycle BMW I3 Pack, Source: BMWBlog

4. Battery: LTI – ROM - Principle

• Thermal model is a linear system (Linear Time Invariant)

Input1_Tin

Input2_Cyl1

Input3_Cyl2

Output1_Tout

Output2_Cyl1

Output3_Cyl2

HeatTemperature

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• LTI can be characterized and indentified with step response (or impulse)• Convolution is used to build any response of this system

• ROM: find a simple LTI to emulate the original CFD response

timetime

4. Battery: LTI – ROM - Workflow

1) Get step responses of the system

3) Use ROM in system simulation

2) Extract ROM

© CADFEM 2017 30Fluent or Mechanical SimplorerSimplorer

Heat

time

Temperature

time

Heat Profile

4. Battery: Application example

© CADFEM 2017

LTI ROM gives the same results as CFD. LTI ROM runs in less than 2 seconds while the CFD runs 2 hours on one single CPU.

X. Hu, S. Lin, S. Stanton, W. Lian, “A Foster Network Thermal Model for HEV/EV Battery Modeling,” IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 47, NO. 4, JULY/AUGUST 2011X. Hu, S. Lin, S. Stanton, W. Lian, “A State Space Thermal Model for HEV/EV Battery Modeling", SAE 2011-01-1364 31

4. Battery: Application example 2

Cell model Battery pack

Heat

Temperature

Pack thermal Model

© CADFEM 2017

Cell Electrochemistry Model

Temp.

Heat loss

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5. Inductive Charging: Wireless Charging for Electro or Hybrid VehiclesWhy?

• Comfortable (no searching for the charging cable, fitting connectors)

• Protection against vandalism at public areas• Automatic wireless charging (several shorter charge cycles

lead to longer battery life)• Fast energy transfer with high efficiency• Dynamic charging while driving

© CADFEM 2017 33

• Dynamic charging while driving

Challenges• Positioning of the vehicle• Stray fields and EMC• Matching network and parasitic effects• Transmission and system efficiency• Detecting foreign objects• Standards and compatibility

Ref.: www.mercedes-benz.de

Ref.: www.qualcomm.com

Ref.: www.toyota-global.com

5. Inductive Charging: BasicsTransformer principle• With closed magnetic circuit:

• Magnetic circuit bundles flow and leads to a lower leakage flux

• Analytical calculation possible• With Air gap:

• Analytically difficult to calculate -> FEM Ref.: Prof. Dr.-Ing. Nejila Parspour, „Induktives Laden – ein Themenschwerpunkt der Elektromobilität“

© CADFEM 2017 34

• Analytically difficult to calculate -> FEM Themenschwerpunkt der Elektromobilität“

1mm 1cm 10cm 1m 10m 100m

100%

50%

0%

Transfer Distance

Effi

cien

cy

Resonance type

Induction type (~15W)Induction type (~50kW)

Microwave type

5. Inductive Charging: Analysis Plan

Electromagnetic field simulation• Identifying of saturated areas• Extracting of equivalent circuit parameters• Position dependent sensitivity analysis • Determination of stray fields and losses

© CADFEM 2017

00

E1

W

+

WM1

W

+

WM2

C1

11.74nF

C2

30.45nF

Rload

3ohm

R1dc

21mOhm

R2dc

7.2mOhm

Current1:src Current2:srcCurrent1:snk Current2:snk

Mx_SS1

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Electrical circuit and system simulation• Circuit optimization (resonant capacitors)• Calculation of the system efficiency

5. Inductive Charging: Demonstrator Model

Components• Two flat cylindrical coils• Ferrite shell (Ground Module)• Ferrite disc (Car Module)• Aluminum shielding plates

Transmitter Coil

Reciver CoilFerrite Disc

Aluminum Shielding Plate

Car Module:

Ground Module:

© CADFEM 2017 36

Position

Gap

Sliding

Ferrite Shell

Aluminum Shielding Plate

Spulen Spezifikationen:• Litzendraht: Æ 0.25mm x 384 strands• Kupfer: 5.8x107 [S/m]• Anzahl Wicklungen: 10

Ferrit:• Relative Permeability: μi = 2400 • Relative Loss Factor: 1x10-9

Speisung:• Spannung: 200 V / 10 kW• Design Resonanz Frequenz: 150 kHz

5. Inductive Charging: Model Simulation with ANSYS

Eddy Current Analyses (Maxwell – Eddy Current Solver)

Magnetostatic Analyses (Maxwell – Magnetostatic Solver)

Preliminary Investigation:

Electromagnetic Field Simulation:

• Maximum B-Fields

• Eddy Currents• Core Losses• Inductance matrix

© CADFEM 2017 37

(Maxwell – Eddy Current Solver)

Circuit and System Simulation (Simplorer)

System Simulation:

Temperature, mechanical stress, electromagnetic radiation

• Inductance matrix

• Resonance frequency • Efficiency

Further investigations

5. Inductive Charging: Eddy Current Analyses – Inductance Matrix

• The self- and mutual inductances are position dependent

• A parametric sweep was used to determine a matrix for the coupling coefficent, self- and mutual inductance

© CADFEM 2017 38

5. Inductive Charging: Circuit Simulation – Equivalent Circuit • An equivalent circuit can be created from the

electric circuit components and the parameter extracted from the electromagnetic field simulation

• Additional losses can be taken into account by additional resistors in the circuit (analytically calculated or measured)

SlR

s=

C 1=

DC Resistance:

Ss

l

Resonant Capacitance:

© CADFEM 2017 39

00

E1

W

+WM1

W

+ WM2C1

11.74nF

C2

30.45nF

Rload

3ohm

R1dc

21mOhm

R1ac

85.656mOhm

R2ac

46.715mOhm

R2dc

7.2mOhm

L1

95.861uH

L2

36.969uH

M12

0.09232

Resonant Circuit Conductiv LossesLoad

LC 2

0w=

Behaviour Model

5. Inductive Charging: System Simulation

SlR

s=

C 1=

DC Resistance:

Ss

l

Resonant Capacitance:

• An equivalent circuit can be created from the electric circuit components and the parameter extracted from the electromagnetic field simulation

• Additional losses can be taken into account by additional resistors in the circuit (analytically calculated or measured)

• Replacing the concentrated quantities with a behavioral model or SPICE model

© CADFEM 2017 40

LC 2

0w=

00

E1

W

+WM1

W

+ WM2C1

11.74nF

C2

30.45nF

Rload

3ohm

R1dc

21mOhm

R1ac

85.656mOhm

R2ac

46.715mOhm

R2dc

7.2mOhm

L1

95.861uH

L2

36.969uH

M12

0.09232

Resonant Circuit Conductiv LossesLoad

Behaviour Model

behavioral model or SPICE model

6. System: Which parts belong to our system?Safety Requirements

Actuators

Battery

© CADFEM 2017 41

Sensors

Electronic Control Units

Operating ConditionsEmbedded Software

Operational Profiles

6. System: ….and how do they interact with each other?

© CADFEM 2017 42

6. System: System simulation – some thoughts to start with

• Which design-stage?

• In which physical domain? Across domains?

• How big is the system:

© CADFEM 2017

• How big is the system: • System with several components across several physical domains• System of Systems

• What are the time-scales?

→Level of abstraction

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6. System: Which Representation?

Reduced Order Model Creation

System Model Interoperability

Embedded Software Integration

Co-simulationwith 3D Physics

Language-Based Modeling

Multi-Domain Model Libraries

© CADFEM 2017 44

Thousands of Built-inComponent Models

Industry Standardsfor System Modeling

Interfaces with all ANSYS 3D Physics 3rd Party SystemModeling Tools

ANSYS SCADEand More

6. System: ECE Model extraction

• FEM to System • model order reduction: ECE-model

(equiv. circuit extraction)• variation of currents Id, Iq and

rotational angle θm

b

© CADFEM 2017 45

rotational angle θm• lookup-table: flux linkage Ψd, Ψq, Ψ0 + torque

• takes into account: saturation due to material nonlinearities

• does not take into account: eddy current effects

a

c

6. System Simulation Motor control

© CADFEM 2017 46

6. System: Next Step: Add driving cycle and thermal model?

• Different time scales!• Existing motor model too

detailed• Use VHDL-AMS model

instead

© CADFEM 2017

instead

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…maybe like this

© CADFEM 2017 48

Advanced Magnetics ModelingElectric Drive Acoustics

Motor / Inductive Charging

Lab

Efficient Motor Design ToolkitMotor-Design Battery

Control logic, softwareSystem Validation

LabElectro-thermal modeling

ROM for system simulation

Design Analysis Operation

© CADFEM 2017

EmagThermal

3D Physical Validation

Concept Design

System Validation

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Many Thanks to

• Martin Hanke• James Goss, Dave Staton, MDL• Matthias Voss• Rene Fuger• Hanna Baumgartl

© CADFEM 2017

• Hanna Baumgartl• Evgeny Rudnyi• Ulrich Bock• Kanchan Mahajan• Jürgen Wibbeler• Christian Römelsberger

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CADFEM – Simulation is more than Software

PRODUCTS Software und IT Solutions

SERVICESAdvice, Support, Engineering

© CADFEM 2017 51

KNOW-HOWTransfer of knowledge

CADFEM in D, A, CH• 1985 founded• 2,300 customers• 11 locations• 220 employees (worldwide > 350)• ANSYS Elite Channel Partner

Career-integrated Master Applied Computational Mechanics

Master‘s Students

150+

Certificate andModule Students

30+

© CADFEM 2017 www.esocaet.com/en/studies

„The master course allows me to apply simulationmethods to their full potential. Furthermore I don‘tonly apply simulation now, I really understand it.“Stefan Hermann, M.Eng.Liebherr Aerospace Lindenberg GmbH

150+ 30+