Temperature prediction of oil-cooled IPMSM for in-wheel direct-drive through lumped parameter thermal model

This paper focuses on estimating the temperature of end winding, in which the highest temperature exists out of all the components, in Interior Permanent Magnet Synchronous Motor (IPMSM) for in-wheel direct drive. A lumped parameter thermal model of IPMSM is suggested with considering core, copper, mechanical, and eddy current losses, which are the heat sources and calculated from finite element analysis to improve the accuracy of the prediction. In addition, the thermal model is comprised of thermal resistances and capacitances determined by the configurations and the dimensions of motor. Finally, an oil-cooling system is covered with the concepts of thermal conductivity, density, specific heat at constant pressure, dynamic viscosity, and flow rate.