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Introduction to Motor Design Ltd and Motor-CAD

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MDL

About Motor Design Ltd

Software developers: Motor-CAD

• Developers of Motor-CAD – world-leading tool for the

design and analysis of electric motors

• High level of customer support and engineering know-how

• Developed with expert electric machine designers.

Consultancy

• Design, analysis & training

• Led by motor design experts with significant industry and

academic experience.

Research

• Involved in collaborative government/EU-funded research

projects

• Collaborate with Universities worldwide to develop electric

machine modelling techniques and create validation data.

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Motor-CAD

• The market leading tool dedicated to the design and analysis of electric motors.

• Enables rapid and accurate electromagnetic, thermal and mechanical analysis of an electric machine across the full operating envelope.

• Designed and developed in close collaboration with expert electric machine designers.

• Embedded engineering expertise.

• Great customer support and response to user feedback.

Motor Design Software

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Motor-CAD

• Covers all typical types of radial flux rotating electric machines

• Motor Types:

‒ Brushless permanent magnet (inner & outer rotor)

‒ Induction‒ Synchronous reluctance‒ Switched reluctance‒ Synchronous wound field‒ Permanent magnet DC‒ Single phase induction

• Uses a combination of analytical and numerical modelling techniques

Motor Design Software

Efficiency map

Transient thermal

analysis

Slot temperature

distribution

3D visualisation and CAD export

Flux Density shading

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Motor-CAD EMag

• Extensive range of parametrised

templates & geometries

• Calculates torque, power, losses,

voltages, currents, inductances, flux

linkages and forces.

• Designs can be input and calculated

in minutes allowing lots of iteration

and full exploration of the design

space; ensuring optimal design decisions.

Motor-CAD electromagnetic module

Interior PM machine design Switched reluctance machine

design

Synchronous wound field machine

designInduction machine design

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Motor-CAD EMag

• Combined 2D finite element and

analytical modelling approach

• Calculates electrical & electromagnetic

performance

• Coupled solution with the thermal model

• Automatically set-up calculations for

different performance tests.

Motor-CAD electromagnetic module

Radial winding pattern Induction machine equivalent circuit

Fourier analysis of the voltage

waveform

Linear winding layout

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Motor-CAD EMag

• Embedded 2D transient FEA solver

• Meshing, boundary conditions automatically set-up

• Advanced calculations such a eddy current in magnets, induction machine rotor bars & AC winding losses.

• DXF and scriptable geometries, custom current waveforms, multi-slice skew.

• Enables engineers to account for complex electromagnetic effects early in the design process

Motor-CAD electromagnetic module

Flux density plot from FEA solver Calculated voltage waveform

FEA geometry and region editor AC loss in a hairpin winding

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Motor-CAD Therm

• Industry standard tool for thermal analysis of electric machines with over 20 years of inbuilt experience.

• Calculates temperature of the motor components in steady-state and transient operating conditions.

• Enables accurate modelling of thermal behaviour within seconds of calculation.

• Enables understanding of main heat transfer paths and opportunities to significantly improve output.

• Allows iteration and full exploration of the design space, alongside electromagnetic analysis; ensuring optimal design decisions.

Motor-CAD thermal module

Visualisation of oil

spray cooling

Thermal network

Radial temperature

distribution Thermal transient solution

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Therm

Cooling Types

• TENV: Totally enclosed non-ventilated

‒ Natural convection from housing

• TEFC: Totally enclosed fan cooled

‒ Forced convection from housing

• Through Ventilation

• TE with Internal Circulating Air

‒ Internal air circulating path

‒ Water jacket as heat exchanger

• Open end-shield cooling

• Water Jackets

‒ Axial or circumferential

• Submersible cooling

• Wet Rotor & Wet Stator cooling

• Spray Cooling

‒ e.g. Oil spray cooing of end windings

• Direct conductor cooling

‒ e.g. Slot ducts with oil

Through

ventilation

with radial

ducts

Fan cooled

machine with

cowling

Water jacket

with axial

channels

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Motor-CAD Therm

• Thermal and flow network generated

automatically

• 3D network includes radial & axial heat

transfer

• Detailed visualisation and calculation of

the slot cross section

• CFD, FEA and empirical correlations

behind all calculations.

Thermal Network

Cross-Section Showing Axial

Temperatures

Thermal Resistance Network

Slot cross section for a

concentrated winding

Slot cross section for

hairpin winding

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Motor-CAD Therm

Manufacturing Data

• Thermal modelling of electric machine can be challenging as thermal behaviour is significantly affected by manufacturing aspects.

• Examples of manufacturing uncertainties that affect temperature rise:‒ Goodness of effective interface between stator and

housing‒ How well the winding is impregnated or potted

• Experience is built into the software to assist users in selecting appropriate values.

Example of

guidance given to

set stator lamination

to housing interface

thermal resistance

Interface resistance and

conductance data that is

suitable for thermal experts

Equivalent interface gap

that is useful for non heat

transfer specialist

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Motor-CAD Lab

• Efficiency & loss maps

• Peak torque/speed curves

• Continuous torque/speed curves

• Duty cycle analysis

• Open & short circuit tests

• Automatically applies maximum torque/amp control strategies to replicate performance of machine with inverter

• Essential calculations for designing and analysing inverter driven machines with range of operating conditions.

Motor-CAD Virtual Testing Laboratory

Calculated

efficiency map in

motoring and

generating region

Calculated losses

over time for a

duty cycle

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Motor-CAD Lab

• To generate the map and cycle data, thousands of operating points have to be calculated.

• We use the FEA and analytical EMagsolvers to build inductance and loss maps of the machine design.

• Couples with the thermal solver to predict combined EMag and thermal behaviour.

• All calculations efficiency maps, duty cycles etc. can be calculated in minutes, and hence used during an iterative design process.

Modelling Approach

Model build

interface in

Motor-CAD Lab

Response surface

of iron losses vs

current magnitude

and angle,

calculated using

the FEA solver

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Motor-CAD Lab

• Machines are often specified on their peak and continuous operating characteristics.

• The peak curve is typically constrained by the inverter current limit and DC link voltage.

• The continuous operating curve is typically limited by the winding and/or the rotor temperature.

• The lab model can be used to easily generate these characteristics curves for any electric machine design.

Peak and continuous operation

Torque is limited

here on maximum

winding

temperature

Torque is limited here on

maximum rotor/magnet

temperature

Transient operation

region

Calculated peak and continuous torque/speed curves

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Motor-CAD Lab

• Losses, efficiency and energy usage can be calculated across any duty cycle.

• The behaviour of the machine is solved with the thermal model to give temperature rise against time.

• The variation of losses and magnet flux (torque/amp) with temperature is accounted for.

• This enables engineers to design a machine with minimum size/cost and optimise the design for maximum cycle efficiency.

Duty cycle analysis

Motor/Generator: Temperature Vs Time

Motor/Generator: Time vs Torque vs Speed Co-solved

electromagnetic

and thermal

behaviour over

cycle

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Motor-CAD Mechanical

• FE solution based

• Very fast – solves within a couple of seconds

• Template or DXF import options available

• Enables engineers to consider Magnetic and Mechanical performance trade-off in design optimisation

Stress Analysis for High Speed rotorsVon Mises Stress in IPM rotor at maximum speed

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Motor-CAD

• Motor-CAD is primarily used by electric machine designers

• It is particularly useful for initial design, topology selection, sizing, analysis and optimisation across the full operating envelope.

• However, it can also be used alongside 3D FEA and CFD tools for more detailed analysis in the latter stages of design.

• Motor-CAD software’s usability means that it can also be used by non-experts in electric machine design.

Usage in development lifecycle

Concept of

Operations

Requirements &

Architecture

Detailed Design

Implementation

Integration,

Test and

Verification

System

Verification &

Validation

Operation &

Maintenance

Verification &

Validation

Time

Initial design, topology &

sizing

Detailed design & optimisation

Engineering product development lifecycle

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Motor-CAD

• Motor-CAD is useful for systems

analysis; to generate reduced order

thermal models, flux linkage/inductance

maps, forces for combined motor and

gearbox analysis, co-simulation with

system tools etc.

• It is also really valuable to use during the motor test and validation process. This often helps provide input data for the testing and helps identify any manufacturing issues with the machine and provides improved modelling for the next design iteration.

Usage in development lifecycle

Concept of

Operations

Requirements &

Architecture

Detailed Design

Implementation

Integration,

Test and

Verification

System

Verification &

Validation

Operation &

Maintenance

Verification &

Validation

Time

Engineering product development lifecycle

Reduced order models, coupling and co-simulation

Test rig input data, model validation &

analysis

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Software Links

Motor Design Limited Software Links

Motor-CAD links to ANSYS software (Maxwell, Mechanical, Fluent)

Motor-CAD couples with OptiSLang to provide cutting-edge optimisation workflow

Motor-CAD links to RomaxDESIGNER software (Transmission Integration & NVH)

Motor-CAD links into GT-Suite for co-simulation and model export

Motor-CAD links to Simulink for electromagnetic and thermal reduced order modelling

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This document contains proprietary information of Motor Design Ltd. Such proprietary information may not be used, reproduced, or disclosed to any other parties for any other purpose without the expressed written permission of Motor Design Ltd. © Motor Design Ltd 2016 All Rights Reserved.

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MDL

About Motor Design Ltd

Research

‒ Concept_e – Prototype Electric vehicle development

with Jaguar Land Rover (JLR)

‒ HVEMS – High Volume E-Machines Manufacturing

Supply. Make-Like-Production prototyping facility in the

UK with JLR

‒ Tevva – Design of SRM motors for Trucks

‒ ReFreeDrive – Rare Earth Traction motors with

improved performance and lower cost (Induction and

Reluctance Motors)

‒ ELETAD – Helicopter electric tail rotor