Design and Optimization of a Slotless High-speed Permanent-Magnet Synchronous Motor with Non-magnetic Fillers in Stator

High power density and high efficiency are the key requirements to be met for the high-speed motor of fuel cell air compressor application. This paper presents a slotless toroidal-winding high-speed permanent-magnet synchronous motor (HSPMSM) with nonmagnetic fillers in the stator. The slotless structure with toroidal windings and non-magnetic fillers was selected to limit high-frequency rotor eddy-current loss, iron losses, torque ripple, while improving the fixation of windings and heat transmission. The basic topology selection is first introduced. Then the multi-objective optimization process, based on genetic algorithm and finite-element analysis of electromagnetic field, is discussed and carried out aimed at finding the best compromise between power density and efficiency for a 15 kW, 120 000 rpm HSPMSM. Finally, the optimal design scheme was selected, exhibiting higher power density and efficiency than the common slotted HSPMSM scheme.