Design optimization for reducing harmonic distortion of flux linkage in low pole flux-switching permanent magnet machines

High-speed machines are gaining interest, especially in traction applications because of their ability to produce high power density with a reduced size. Flux-switching permanent magnet (FSPM) machines are ideal for such applications since they have a simple rotor structure that can operate at very high speeds and utilize PM in the stator to achieve high power density. It is also desirable to keep the operating frequency at a minimum possible value to reduce core losses and cost of power electronics. A 6-stator slot, 4-rotor pole (6/4) FSPM machine has the lowest operating frequency for a three-phase FSPM configuration. This research aims at exploring design modifications to minimize the even order harmonic content and cogging torque to make the 6/4 configuration practical for highspeed applications. The analysis and methods proposed in this paper will be useful in tackling harmonic content of FSPM machines in general. An alternative structure with dual-stator configuration is provided to minimize harmonic distortion of the 6/4 FSPM machine in the paper.