Post on 15-Apr-2017
transcript
Electric Motor Thermal Optimization for Hybrid Vehicle Application
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Demand for electric motor capable of running at Higher-power duty cycles will continue to rise As Over-sizing the electric machine is getting costly, thermal efficiency improvement has much more important role to play Customer wants most efficient motor with higher
o Cost ($/kW) o Weight (kW/kg) o Volume (kW/L)
Efficient thermal management can improve power capability within cost/efficiency constraints as well as improve performance of an electric motor
Introduction
Source: http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2011/adv_power_electronics/ape030_bennion_2011_o.pdf
Left side of the triangle is the
specification
Right Side is the performance
At the top is the application,
middle is component and at
bottom is the thermal
Thermal Design Optimizationn Hierarchy
Source: http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2011/adv_power_electronics/ape030_bennion_2011_o.pdf
Motor Thermal Optimization Paths
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Motor Thermal Optimization Strategy
Motor Thermal
Optimization
Specification/Application Driving Profile Optimization Points Transient & Continuous Thermal Operating Points Full Load Curve Efficiency Max allowable losses at optimization points Temperature limits Geometry Restriction Cost
Packaging /Mechanical Constraints Machine Type Geometry Materials Thermal Resistance Circuits
Cooling Optimization Cooling Fluid Cooling Mechanism ( Jacket, Fin, Jet) Flow optimization Area Enhancement Thermal transport
Design Selection Flowpaths: Hybrid, Spray nozzle, Oil Flow rate (Cooling) Operating Points (Customer) Cost
Cooling Performance
(UA)
Thermal Resistance
(Rth )
Loss Calculation
Thermal Load Distribution
Thermal Modeling
Thermal Optimization
Source: http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2011/adv_power_electronics/ape030_bennion_2011_o.pdf
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Motor Thermal Optimization Strategy
Motor Thermal
Optimization
CTS
o Develop Heat Generation Model o Review Past Motor Thermal Test Data
Thermal Model
o Develop Thermal Model o Debug and Correlate Thermal model
Cooling Technology
Selection
o Identify Cooling limitations o Identify Areas of Improvement
o Pugh Matrix for multiple New Concepts o Customer Collaboration for Optimum Design
Design Selection
Source: http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2011/adv_power_electronics/ape030_bennion_2011_o.pdf
Motor Thermal Optimization Strategy
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Electro-Magnetic FEA Thermal Resistance Circuit
Thermal Equivalent Motor Circuit
Motor Node Temperature Prediction
Motor Losses
Resistance Value
Source: http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2011/adv_power_electronics/ape030_bennion_2011_o.pdf
Customer Driving Profile
Motor Thermal Optimization Strategy
Source: www.fueleconomymy.gov http://www.fueleconomy.gov/feg/fe_test_schedules.shtml
Source: http://techno-fandom.org/~hobbit/cars/heatgames/results-03.html
Source: www.fueleconomymy.gov http://www.fueleconomy.gov/feg/fe_test_schedules.shtml
As electric motor efficiency varies based on load points, motor must operate at most efficient points Thermal optimization should be based on customer specific performance points Typical such points usually defined by following:
Speed (RPM) Torque (Nm) Energy Loss (Kj) Duration (Sec)
Motor Thermal Optimization: Typical Driving Profile
Motor Thermal Optimization: Typical E-mag Results
Motor Thermal Optimization: Typical Motor Nodal Circuit
−
−
−
−+=
−−f
ff
TR
TR
TR
TRRRcmdt
dT 11111116
162
1_21
161_211
1
Conductive Resistance
Motor Nodal Thermal : Governing Equations
g
nj
j ji
ijipi Q
RTT
dtdTcm
i+
−=∑
=
=1 _
Governing Equation
∆=
LTKAqconduction
KAL
TTq ji )( −=
KALRcond =
Convective Resistance
ThAqconvection ∆=hA
TTq ji
1)( −
=hA
Rcond1
=
Typical Nodal Solution for Temperature
Get Coolant Property Inputs
(Flowrate & Temperature)
Get Motor Load Inputs (Speed, Current, Voltage)
Check if Inputs are Valid
No Take Default Action
Define Thermal Resistance Network at
Time = T
Yes
Calculate Change in Temperature Between Time =T and
Time = T-TaskRate
Add Change in Temperature To
Temperature from Previous TimeStep
Motor Thermal Nodal Model: Solution Tree