Optimal combination of stator and rotor pole numbers in flux-switching PM brushless AC machines

Abstract

A simple analytical method is developed to compare the combinations of stator and rotor pole numbers in flux-switching PM machines in terms of back-EMF and electromagnetic torque. The winding connections for machines having all poles and alternate poles wound are determined, based on the coil-EMF vectors. The conditions are established for balanced symmetrical back-EMF waveform. It shows that the optimized rotor pole number should be close to the number of stator pole, while larger torque can be obtained by the machine with relatively higher rotor pole number.