Develop a Hybrid Thermal Simulation Method for EV Motor Performance Analysis, Optimization and Select Cooling Technology

Abstract

The EV motor generates power losses during operations. The losses are dissipated as heat by motor cooling systems. The motor parts set thermal limits for safe and efficient operations. The motor go beyond these limits will have issues like performance reduction, lifetime, and insulation degradations. An optimized cooling system eliminate these thermal issues and ensure safe, efficient operation. The optimized cooling system achieved with hybrid simulation method proposed in this paper. The method combines the LPTN modelling technique with CFD Analysis results. The proposed method capable to optimize an EV motor with temperature distributions with safe hotspots, high efficiency & torque/power density, and overload time capability. The Motor LPTN model developed for passenger car requirements with PMSM motor as target motor topology. The motor heat transfers are modelled with analytical equations to capture the dominant heat paths. The motor endspace regions analyzed with CFD simulation to calculate wall heat transfer flux as complex windings, housings present here. The motor thermal model accuracy enhanced as CFD analysis used to calculate wall heat transfer flux at motor inner walls. The hybrid thermal model gives out the motor temperatures and performance as results. This hybrid simulation method eliminates error and high effort wasted during motor design iterations. The simulation method validated with measurements with accuracy around 90 to 95 %. The hybrid simulation method suitable for sensitivity analysis, cooling system study and optimization study.