Multilayer Winding Effect on Performance of Flux-Switching Permanent Magnet Machines

Flux-switching permanent magnet machines (FSPMMs) with fractional-slot concentrated windings (FSCWs) are good candidates for electric vehicle applications due to their simple doubly salient construction, the magnets and windings being removed from rotor to stator, and strong mechanical robustness. They have attracted considerable interest from academia and industry not only because of their essentially sinusoidal phase back electromotive force (back-EMF) waveform, but also their high electromagnetic torque/power densities. Although the FSCW can reduce the end-winding overlap and deliver near-sinusoidal back-EMF, it still contains a little amount of harmonics so as to result in other more losses. The inherent nature of the FSPMMs with different types of FSCWs has not been investigated in detail till now. In this paper, a typical three-phase FSPMM with 12/13 stator teeth/rotor poles with FSCW is employed, to investigate the effect of number of winding layer on key electromagnetic indexes based on finite element analysis. Comprehensive simulations demonstrate that significant reduction can be got on torque ripple, total harmonic distortion of back-EMF and losses with higher number of winding layer.