MotorSolve analysis of the 2010 Toyota Prius Traction

Transcription

MotorSolve analysis of the 2010 Toyota Prius Traction
MotorSolve analysis of the 2010
Toyota Prius Traction Motor.
Presented by:
James R Hendershot
Location: Hilton Rosemont, Chicago
O’Hare
Date: Oct. 27, 2015
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Presenter:
James R Hendershot
Jim has over 40 years experience in practical hands-on PM & SR brushless motor design, manufacturing
and development. With past key employments at United Technologies, General Motors, Clifton Precision,
Berger Lahr & Pacific Scientific, he has designed hundreds of brushless motors for computer disc drives,
servo systems, high speed machine tool spindles, traction drives, hybrid vehicles, micro-turbine and diesel
generators. He has written numerous technical papers, publications and presented tutorials on many different
electric motor topics. Hendershot is the co-author with Professor TJE Miller for two of the leading design books on Permanent books on
Permanent Magnet Motor and Generator Design (ISBN 1-881855-03-1, 1994 & ISBN 978-0-9840687-0-8, 2010).
Jim teaches detailed motor design training courses (including workshops) at public venues, conferences and custom designed workshops
tailored on-site for companies around the World. Jim Hendershot holds a B.S in Physics from Baldwin Wallace University in Berea Ohio
along with additional E.E. & M.E. engineering studies at Cleveland State University as well as graduate courses at Case-Western
University in Cleveland Ohio. He specializes in the design, analysis, sourcing, manufacturing and teaching of both electro-magnetic and
permanent magnetic devices. In addition to continuing studies in magnetics and electric machines.
Jim has enjoyed a long and rich association with Dr. Tim Miller, founder of the SPEED Consortium at the University of Glasgow
combining Jim’s practical hands-on motor design skills with TIM’S theoretical knowledge and research
For the past few years Jim has also been associated with Infolytica Corp, Prof. Dave Lowther (of McGill University), Prof. Ernie Freeman
retired from Imperial College, London and their staff for continued development and research involving the design and research for
electric motors and generators.
Jim Hendershot developed a Dyno-Kit for teaching electric motor drives used by over 120 US Universities and Colleges for Prof. Ned
Mohan of the University of Minnesota. These are used for the lab portion of their Electric Drive Courses.
Jim Hendershot has created a series of 36 electric machine design lectures for the University of Minnesota, funded by the US Navy
Research Labs that are available on YouTube. (9 to 10 hrs. of lectures covering all aspects of practical electric machine design).
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For thousands of years man could only walk here and there.
By 4000 to 5000 BC man began to ride horses
Around 2000 BC horses were used to pull carts and carriages
Early US settlers used horse & oxen drawn large wagons to
“go West” (Like modern RVs & campers)
In 1605 horse drawn carriages were used on the streets
of London.
By 1640 the London horse drawn carriages added springs
for comfort and with a driver.
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Introduction
In the late 19th and early 20th century, electricity was the
preferred power source for automobile propulsion. US had
no highway systems because passenger trains were used
for long distance travel.
Gasoline was known but no infrastructure available
Steam powered cars were also tried.
By 1920 thanks to Henry Ford, IC engine improvements
and the growing petroleum infrastructure, thanks to John
D Rockefeller, gasoline power dominated automobiles
until this present day.
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History summary of automobile propulsion:
1768 French steam engine powered car by Nicolas
Cugnot
1832 Robert Anderson ran first electric motor driven car
1885 Karl Benz made first 4 wheel gas powered car
1888 First noted (4) wheel E-Car, Flocken Elektrowagen
1893 First American car was developed by Charles
Duryea
1897 Stanley Steamer in Newton MA, sold 200 cars
1908 Ford Model-T introduced (Internal combustion
gasoline powered engine)
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Early examples of E-Vs
1907
Detroit
1888
Flocken
1912
Edison
1910
POPE
Limited gasoline
availability and
cars needed for
only short trips.
Trains used for
long distances)
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First lead-acid
storage batteries
developed in 1859
Frenchmen named
Gaston Planté
1918
Woods
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First (serious?) electric car since in nearly 100 years
EV1 by General Motors
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EV1 by General Motors
Production years 1996 to 1999
EV1s total produced total 1117 cars
Range 70 to 90 miles per charge
Motor type, (3) phase aluminum rotor
AC induction motor
Maximum output power = 103 kW
Peak output torque = 149 Nm
Base speed = 6500 rpm
Max speed = 13000 rpm
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Toyota Motor Car Corp. EV or Hybrid development
Sometime in the middle 90s, Toyota began development
of a hybrid electric vehicle to compete with the GM EV1.
First production in Japan in 1997 (before the EV1 was
cancelled by GM in 2003.)
Toyota PRIUS first sold in the USA in 2003
Second generation PRIUS sold in USA in 2004
Third generation PRIUS sold in USA in 2010
Fourth generation PRIUS in USA scheduled for 2016
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World hybrid Hybrid/EV sales 2003 to mid 2015
Total world production of hybrid or electric vehicles
since 2003 = 3,540,199
Total world production of Toyota’s share = 2,487,564 ( 70%)
Total world production of Prius share = 1,731,717 (49%)
755,847 difference from other hybrid models designed & sold
by Toyota such as, Camry, Avalon, Highlander & Lexus.
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Electric traction motor options
for hybrid and EV vehicles.
IM
RSM
IM, RSM & IPM/SPM
use similar stators &
phase windings with
different rotors
IPM or
SPM
Switched Reluctance
New rotor & stator
Cross sections of
electric machines by:
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Maximum flux densities of materials limit performance
No matter which machine you choose for a motor/generator
its torque density is limited by two important magnetic
materials.
1-Hard materials (permanent magnets) can only produce a
maximum flux density of 1.4 tesla
2-Soft materials (electrical steels) become saturated at
maximum flux densities in the range of 2.1 to 2.4 Tesla
I offer each of you a challenge to invent new materials
A new material with a negative permeability would be a good
start, then higher temperature super conductivity materials
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Specific power density of current piston
engines, turbines & electric motors
Cooling and efficiency are very
important for electric propulsion
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Power density of modern EV traction motors
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ELECTRIC MACHINE POWER
DENSITY COMPARISONS
TESLA 4.5 kw/kg (225 kw peak for 30 sec.)
New TESLA 4.34 kw/kg
BMW i3 = 2.5 kw/kg (at 125 kw max)
Siemens 5 kw/kg
Aero PM motor
(260 kw @ 50 kg)
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Review of the Toyota Prius PM-AC traction motors
Toyota selected the PM-AC synchronous motor because it has the highest power
density, highest power factor, highest efficiency and easiest to cool of any known
electric machine. (Perhaps a bit more expensive than that other choices due to use of
rare earth magnets.
However if AC Induction motors are used they must use copper rotors which increases
their costs also. (The extra difficulty of rotor cooling and lower power factor tends to
offset the magnet cost of the PM-AC machines.)
There are two types of PM-AC synchronous machines, SPM & IPM.
IPMs were chosen for several important reasons for automobile traction.
Wide constant power speed range range
Robust rotor without additional retainment
Lower cost rectangular permanent magnets (no grinding required)
Added reluctance torque output from same source current for magnet torque
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Two types of PM-AC synchronous machines, SPM & IPM.
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Prius 2003 IPM style (8 poles) Prius 2004 IPM style (8 poles)
The magnets & pole tops are retained against centrifugal forces by thin webs
at the magnet ends. Careful stress analysis is required as well as field solutions
to minimize flux leakage. (Said to be as high as 20 % leakage)
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Toyota IPM rotor dimensions
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Rotor Punching comparison for IPM Toyota electric traction motors
Actual Prius rotor punching has mass
reduction pockets that also facilitate cooling.
This can be modeled by importing a cad
created rotor DXF file in MotorSolve or in
MagNet.
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PM Generator rotor for 2004 Prius
2010 Toyota Prius PM generator
12 slot, 8 IPM poles, V shaped
PM Generator for 2010 Prius
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Model (reverse engineer) 2010 TOYOTA PRIUS traction motor
1-Using Infolytica’s powerful electric motor template based Field Solver known as
MOTORSOLVE, we can load the program, select motor type-Brushless DC motor,
answer no to sizing question.
2-Select General Settings & fill out the input parameters taken from the data
provided by ORNL on slides 23, 24 & 25.
3-Select Stator and fill in the required inputs also from the ORNL slide data
4-Then select Rotor and fill in the required inputs from the ORNL slides
5-Select Stator Windings and fill in the phase winding data from the ORNL slides
6-Select Materials and select both the electrical steel and the magnet grade from
the list provided.
7-Solve for various performance Results, compare with ORNL test data & learn
how to design these types of IPM PM-AC synchronous machines.
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The input results, right side under General Settings, left side
Input values from
ORNL data
Note: the cross section will not look like the one shown
until after all rotor and stator inputs are complete
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No rotor template is available that allows the creation of extra holes
inside used for mass reduction and cooling. This can be created
using CAD & imported as a .dxf file
The open circuit air gap flux density can be compared
Rotor IPM
With variable
orientation
Rotor IPM
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DXF imported
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Stator inputs
Select:
Stator (round)
Input values from
ORNL data
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Setting the IPM rotor parameters
Select:
Rotor (with
variable
orientation)
Input values from
ORNL data
A long & careful study of web thickness, magnet width & orientation
angle required to optimize the reluctance torque & magnet torque.
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Typical total torque output of an IPM machine
equals reluctance torque plus magnet torque
Peak torque @
angle = 36 deg.
PM torque function of magnet grade, Perm. Coef. & magnet area
Reluctance torque function of salient pole width & Inductance ratio
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Varying the web between magnetic poles from 1 to 8 mm
Critical design task for IPM design
Web thickness effects the saliency Lq
& Ld ratio
Balance the magnet torque
and the reluctance torque
Requires many tedious trial magnetic
field solutions
As web gets larger, the magnet
“V” angle increases.
There are many variations possible,
such as multiple magnet layers &
flux barriers.
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D & Q axis torque plots of 2010 Prius motor
Saliency
width
I
30 deg. E optimum
gamma angle for
max torque
6 deg. M
advance
q
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Phase Winding layout
Select:
Stator (round)
Note: This is a single layer winding (one coil side per slot).
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Input values from
ORNL data
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Winding slot position list
Phase Windings are Selected based upon highest Winding Factor
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Material selection, for shaft, magnets, stator core, rotor core & conductors
Select:
Materials
Select material choices
from those included in
data bases or add new
materials.
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Simulated back EMF (O.C.) @ 7200 rpm
The back emf can be simulated
at any RPM setting.
This example is at 7200 RPM,
the speed where the back EMF
equals 650 VDC peak, or the
same voltage as the DC rail
voltage.
Without field weakening
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Simulated back EMF (O.C.) @ 13,500 rpm
With no field weakening
the back emf is about 1300
VDC peak at 13,500 rpm. This
means that Toyota used field
weakening which can be
modeled using a current
advance angle.
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Cogging torque simulation @ 100 rpm
Number of data
point settings
Accuracy settings
Increase from 1
default to 3
Select:
Cogging torque
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Open Circuit flux distribution
Note: High leakage flux in
bridges & posts required
for magnet retention
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Simulated back EMF (O.C.) @ 1000 rpm
From choice of phase
& line Select:
Line, Phase
Slightly less than 100 V
peak at 1Krpm
Select :Back EMF
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O.C. back emf with one stator slot skew (1000 rpm)
Under stator design,
set skew to 7.5 (Deg.)
and solve for Back EMF
Note: Slight skew (rotor or stator) shapes the line to line
back EMF closer to a true sine wave reducing harmonics
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Air gap flux plot with standard TOYOTA IPM rotor
Peak air gap flux ~ 0.8 T
Result of leakage flux
from IPM post & bridge
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O.C. flux plot with zero magnet to magnet leakage inside rotor
Post & bridge values
set to zero to prevent
leakage form magnet
to magnet in rotor
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O.C. Back Emf plot with zero magnet to magnet leakage
At 1000 rpm & zero internal
rotor leakage the peak back
EMF has increased from 100
V to about 145 V
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O.C. air-gap flux plot with zero magnet to magnet leakage
Peak air gap flux ~ 1.0 T
With zero leakage from
IPM post & bridge.
This leakage represents
20% loss in flux linkage
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Setup for simulation of torque including magnet & reluctance components
Select:
PWM analysis
Select: Torque, Magnet & Reluctance
Set angles: 0, 90, 5
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Torque vs Speed plots, 650 VDC, 0 advance and 45 deg. advance angles
Select:
Torque vs. speed
Note: generating region
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Input:
Advance angle 0, 45
Speed, 100, 13500, 100
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Torque vs Speed plots, 650 VDC, 0 advance and 35 deg. advance angles
Note: generating region
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Input:
Advance angle 0, 45
Speed, 100, 13500,
100
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Current reduced 25%
Torque vs RPM plots, 0 to 45 deg. Advance (650 VDC bus)
Note: With zero advance, 7200 rpm is
max. speed attainable with 650 VDC.
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2010 Toyota Prius 8 pole, 48 slot IPM machine
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Thermal analysis by
Adrian Perregaux
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3D model for thermal analysis
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Thermal analysis by
Adrian Perregaux
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Output torque vs current (Toyota 2010 Prius)
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Adrian Perregaux
2010 Toyota Prius cooling analysis by internal oil spray cooling
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Thermal analysis by
Adrian Perregaux
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Peak flux distribution of Prius 2010 motor
45 deg. advance
1.92 T in teeth
200 Nm
150 A
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Thermal analysis by
Adrian Perregaux
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Open circuit flux distribution of Prius 2010 motor
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Thermal analysis by
Adrian Perregaux
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Temperature rise of key components @ 70% duty cycle
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Thermal analysis by
Adrian Perregaux
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Simulated vs. measured temperature rise Deg. C vs. seconds
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Thermal analysis by
Adrian Perregaux
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Efficiency Plot of 2010 Toyota Prius motor (Motorsolve)
Linearized efficiency plot for fast solution time
Select Efficiency and set up with parameters on right
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Efficiency Plot of 2010 Toyota Prius motor (ORNL)
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Efficiency Plot of 2010 Toyota Prius motor (Motorsolve)
Linearized efficiency plot (Takes about one hr. to solve)
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ISBN 0-19-859389-9
ISBN 978-0-9840687-0-8
RED BOOK
GREEN BOOK
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