Analysis of Back-EMF Waveform of a Novel Outer-Rotor-Permanent-Magnet Flux-Switching Machine

In this paper, a novel outer-rotor-permanent-magnet flux-switching (ORPMFS) machine is proposed and analyzed. First, the geometric topology of the ORPMFS machine is introduced. Then, the PM-excited magneto motive force and open-circuit air-gap flux density are analyzed. Throughout the analysis, the ORPMFS machine is found to have the same air-gap flux density waveform as surface-mounted permanent magnet machine. Furthermore, the analytical equation of the back-electromotive force in the ORPMFS machine is deduced. Then, based on the analytical equation, different combinations of stator slot and rotor pole numbers are evaluated. Finally, the analytical results are verified by 2-D finite element analysis results.