Modeling and Investigation on Electromagnetic Noise in PM Motors With Single- and Double-Layer Concentrated Winding for EV and HEV Application

The radial force and the torque pulsation are identified as two main causes of electromagnetic noise and vibration in permanent magnet (PM) motors for electric vehicle (EV) and hybrid EVs systems. The aim of this paper is to systematically investigate the influence of pole and slot number combinations on noise and vibration characteristics of fractional-slot PM motors with either singleor double-layer concentrated windings. Preferentially, the explicit magnetic field equations are developed for analyzing the radial vibration force and the torque pulsation by the aid of Schwarz-Christoffel conformal mapping. Subsequently, an in-depth investigation of pole (2p) and slot (Qs) number combinations is carried out to provide a detailed finding of noise behaviors due to the electromagnetic origins. The investigation on the electromagnetic noise is performed depending on the several majorSpp families. Finally, the relationship between the vibration mode order and the torque variation is established to provide the comprehensive characteristics of the electromagnetic noise.