Simulating the Toyota Prius electric motor

FEA ANALYSIS

OPTIMIZER

INTEROPERABILITY

SERVICE

General-purpose multi-physics design and analysis software for a wide range of applications

Automatically selects and manages multiple goal-seeking algorithms

Built-in circuit modelling and interfaces to leading CAD packages

Technical support, training and consultancy services available for software usage and applications.

Simulating the Toyota Prius electric motor Robert Kaczmarek Vice President of Sales and Marketing

Introduction •

Opera Machines Environments

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PRIUS motor characteristics – geometric dimensions – material characteristics

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Model building – default templates – customisation – analysis

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Results and comparison – static – dynamic – 2D vs. 3D

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Simulating the Toyota Prius electric motor

18 September 2012

Cobham Technical Services

Opera Machines Environments

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Grew from a loose set of Opera-2d COMI files that were developed by support / application engineers – Simple construction of geometry

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$CONSTANT commands to define parametric values – Edit files manually

– Example analyses

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Set up multiple static simulations for cogging torque

– Post processing

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Determine the voltage in a 3-phase winding based on flux distribution

The introduction of dialogs with pictures allowed for development of this product


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Opera Machines Environments • •

Wizard style data entry Create models in minutes – Entire geometric, material and excitation definition – Save and load existing machines to easily create variant designs – Choose from a range of standard results output automatically

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Open source – Written in Opera command language – Customise existing machines – Add new machine types – Add new post-processing calculations

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Optimize models – Upcoming generation of environments integrated with Optimizer

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Universal/expandable – Fast model building tool – Import existing models to use standard analysis/post-processing scripts

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PRIUS motor characteristics •

The 2004 Toyota PRIUS traction motor is modelled and analyzed using the Opera 2D Machines Environments

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The results are compared with experimental data provided by Oak Ridge National Laboratory (ORNL) in a series of reports [1]-[5]

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[1] Hsu, J.S.; Ayers,C.W.; Coomer, C.L.; Report on Toyota/Prius motor design and manufacturing assessment, Oak Ridge National Laboratory, July 2004, ORNL/TM-2004/137 [2] Hsu, J.S.; Ayers, C.W.; Coomer, C.L.; Wiles, R.H.; Campbell, S.L.; Lowe, K.T.; Michelhaugh, R.T.; Report on Toyota/Prius motor torque capability, torque property, no-load back emf and mechanical losses, Oak Ridge National Laboratory, September 2004, ORNL/TM-2004/185 [3] Ayers, C.W.; Hsu, J.S.; Marlino, L.D.; Miller, C.W.; Ott, G.W.; Oland, C.B.; Evaluation of 2004 Toyota Prius hybrid electric drive system interim report, Oak Ridge National Laboratory, November 2004, ORNL/TM-2004/247 [4] Hsu, J.S.; Nelson, S.C.; Jallouk, P.A.; Ayers, C.W.; Campbell, S.L.; Coomer, C.L.; Lowe, K.T.; Burress, T.A.; Report on Toyota Prius motor thermal management, Oak Ridge National Laboratory, February 2005, ORNL/TM-2005/33 [5] Staunton, R.H.; Ayers, C.W.; Marlino, L.D.; Chiasson, J.N.; Burress, T.A., Evaluation of 2004 Toyota Prius hybrid electric drive system, Oak Ridge National Laboratory, May 2006, ORNL/TM-2006/423

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PRIUS motor characteristics

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Permanent Magnet Synchronous Machine

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48 slots

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8 poles

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3 phase

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V-shaped magnets

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250 A nominal current

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3000 rpm rated speed

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Geometric dimensions

– Stator

– Rotor

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Stacklength 83.56 [mm]

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Material characteristics – M19 steel

– permanent magnets

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Model building ME2D – default templates

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Model building ME2D – default templates

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Model building ME2D – customization

Stator

After

Before

Rotor

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•Modify the air regions at the top of the magnets using the

customRotor.comi

// Set the regions to edit $constant #REG_customAir 51 $constant #REG_customMag 50 //================== // EDIT THE MAGNETS //================== // Points are numbered clockwise from the top-left corner of the magnet. // Create new point on the side of the magnet next to the air region SPLIT Reg=#REG_customMag corner1=2 corner2=0 // Recover the position of points on the magnet edge EDIT REG1=#REG_customMag REG2= REG1 OPTION=CORNER NUMBER=2 NEWX=X NEWY=Y | #XM2=X | #YM2=Y EDIT REG1=#REG_customMag REG2= REG1 OPTION=CORNER NUMBER=4 NEWX=X NEWY=Y | #XM4=X | #YM4=Y // Move newly created point EDIT REG1=#REG_customMag REG2= REG1 OPTION=CORNER NUMBER=3 NEWX=(0.3*#XM2+1.7*#XM4)/2 NEWY=(0.3*#YM2+1.7*#YM4)/2 #XM3=(0.3*#XM2+1.7*#XM4)/2 | #YM3=(0.3*#YM2+1.7*#YM4)/2 // ================================================= // Modify the air regions at the top of the magnets // ================================================= EDIT REG1=#REG_customAir REG2=REG1 OPTION=CORNER NUMBER=6 EDIT REG1=#REG_customAir REG2=REG1 OPTION=CORNER NUMBER=5 EDIT REG1=#REG_customAir REG2=REG1 OPTION=CORNER NUMBER=4 EDIT REG1=#REG_customAir REG2=REG1 OPTION=CORNER NUMBER=2 EDIT REG1=#REG_customAir REG2=REG1 OPTION=CORNER NUMBER=3

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NEWX=#XM3 NEWY=#YM3 NEWX=#XM3+1.065 NEWY=#YM3-1.27 NEWX=#XM3+1.065+2.6 NEWY=#YM3-1.27 NEWX=#XM2+1.522 NEWY=#YM2-1.814 NEWX=#XM2+1.522 NEWY=#YM2-1.814-1.421

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•Modify the curvature of the stator slots bottom using the customStator.comi

// ================================================= // Modify the curvature of the stator slots bottom // ================================================= // Calculate reference parameters $constant #slotRad 5.6388/2 $constant #centre #irstyoke-#slotRad $constant #angle 360/(#slots*2) // Calculate new points position $constant #pt5x #centre*cosd(#angle)+#slotRad*sind(#angle) $constant #pt5y #centre*sind(#angle)-#slotRad*cosd(#angle) $constant #pt6x #centre*cosd(#angle)+#slotRad*sind(#angle+45) $constant #pt6y #centre*sind(#angle)-#slotRad*cosd(#angle+45) // Modify point position EDIT REG1=2 REG2=REG1 Option=Corner Number=5 NEWX=#pt5x NEWY=#pt5y EDIT REG1=2 REG2=REG1 Option=Corner Number=6 NEWX=#pt6x NEWY=#pt6y EDIT Reg1=2 Reg2=REG1 Option=Side Number=5 Curvature=-1/#slotRad N=3 EDIT Reg1=2 Reg2=REG1 Option=Side Number=6 Curvature=-1/#slotRad N=3

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Model building ME2D - customization

Advanced mesh properties

Meshed model – ready for analysis

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Model building ME2D - analysis •

Types of analysis – ST DC

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direct current static analysis, to obtain static snap-shots of the fields in the motor output : – cogging torque, using a fine time step and no excitation currents – static torque vs. angle, over the entire electric period

– ST AC

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alternating current analysis output: – nominal torque

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rotating machines analysis, constant speed, variable speed or mechanically coupled output: – torque vs. speed characteristic

– RM

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Results

Cogging torque

DC static torque

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Results

Steady state torque

Dynamic torque (mechanically coupled)

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Results

Line to line back-EMF

Back-EMF vs. speed

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3D Machines Environments

• Model created with the 3D Machines Environments • Custom rotor imported from 2D model • Static and dynamic analysis available

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Results comparison 2D vs. 3D

Cogging torque 2D

Cogging torque 3D

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Results comparison 2D vs. 3D

Static torque 2D

Static torque 3D

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Conclusions

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Establish FEA analysis best practices around your designs

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Establish clear design objectives up front

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Know when to use 3D analysis

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Use template driven analysis to drive down total analysis time when possible

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