Thermal analysis of high-speed permanent magnet motor with cooling flows supported on gas foil bearings: part I - coupled thermal and loss modeling

Thermal analyses of high-speed Permanent magnet (PM) motors with high energy density and large losses are crucial in the design stage of machines to prevent possible thermal failure. This paper provides a three-dimensional thermal model of a PM motor operating at ultrahigh speeds, coupled with electromagnetic loss analyses for heat generation and fluid dynamics of cooling flows. We perform a detailed investigation of the loss mechanisms—electromagnetic and mechanical—and the heat transfer paths within the machine. The electromagnetic motor loss is predicted based on measured motor input currents. The thermal model is solved iteratively by calibrating the electromagnetic losses with predicted temperatures. The thermal model is also validated by comparing the simulation results to experimental measurements and achieving an error less than 12%. Finally, this presented model is shown to be a reliable tool for thermal management of high-speed PM motors with cooling flows.