Thermal comparison of a CFD analysis and a lumped parameter model of an air-cooled induction machine for EVs

Abstract

Thermal analysis of Electric Machine for Electric Vehicles (EVs), is crucial for precisely predicting the temperature distribution. In the paper, for a forced-air cooled induction machine, two methods of thermal models analysis are compared with measurements. The first numerical method is Computational Fluid Dynamics (CFD) over Finite Element Method (FEM). And the second one uses Lumped Parameter Method (LPM). For the analysis based on CFD over FEM, a 3D induction machine is modeled with force-air cooling housing. The air flow is simulated and the losses are calculated as heat source for thermal models. FEM is coupled with CFD to get the thermal field distribution. For the LPM, the equivalent thermal resistance of winding, the heat transfer coefficients of the airgap and forced air are calculated in the LP thermal model. Finally, Measurement results are determined by PT100 embedded in winding end, as well by infrared instrumentation for measuring the image on the shell thermal distribution. Experimental validation is presented and the conclusion can be drawn from comparing these aspects of two methods, providing some reference for the research applied in motor for EVs.