Forced Air Cooling of a High-Speed Permanent Magnet Motor

This paper discusses the cooling of a 100 kW high-speed permanent-magnet (PM) motor, with a maximum circumferential velocity of 117 m/s. The electrical losses have been calculated by a two-dimensional time-stepping finite element model and the cooling has been analyzed with computational fluid dynamics. Calorimetric measurements have been performed on a prototype. Computational and experimental results are compared for three different operation points. The results of the study indicate a need for improved steady-state models of high-speed PM motors. Available simulation tools overestimate rotor heating and underestimate stator heating. It is urged for further experimental and simulation analyzes.