Analysis of Stator-Slot and Rotor-Pole Combinations of Axial Modular-Flux Reversal Permanent Magnet Machine

This article investigates the influence of stator-slot and rotor-pole combinations on torque performances in axial modular-flux reversal permanent magnet (AM-FRPM) machines. Based on the slot-conductor back-EMF star vector theory, the winding factors of all stator-slot and rotor-pole combinations are improved by adopting toroidal windings. In addition, based on a magnetomotive-force and permeance model, the candidates of stator-slot and rotor-pole combinations with higher torque capacity can be determined by analyzing the harmonic combinations between the PM and armature reaction field. Besides, the cogging torque is suppressed by selecting the corresponding angle between rotor modules for different stator-slot and rotor-pole combinations. Finally, an electromagnetic performance comparison between a conventional FRPM machine and three AM-FRPM machines candidates with attractive torque performances is conducted, and the experiments are constructed to verify the theoretical analysis.