A Novel Hybrid Excitation Flux Reversal Machine for Electric Vehicle Propulsion

A novel hybrid excitation flux reversal machine (HEFRM) is developed for application in electric vehicle propulsion. The proposed machine has a simple reluctance rotor and a stator with conventional ac armature windings and concentrated dc field windings. Besides, there are also permanent magnets (PMs) on the stator teeth. The PMs on each tooth have the same polarity, and the PMs on the adjacent two teeth have different polarities. In this paper, the feasible slot-pole combinations and equivalent circuits of the HEFRM are introduced, and the influences of several key design parameters such as rotor slot number, ratio of field winding to total winding, ferromagnetic pole arc, stator slot opening ratio, and rotor slot opening ratio on torque density and power factor are investigated by finite-element algorithm. Moreover, to verity the advantages of the hybrid excitation, the torque-speed envelop and power factor-speed envelop of the proposed HEFRM are compared to that of its solely PM excited counterpart. Finally, an HEFRM prototype is built and tested to validate the theoretical analysis.