Torque Characteristics Improvement of Flux-Switching Permanent Magnet Machines From the Perspective of Rotor Salient-Pole Modulator

Aiming to improve torque characteristics, a rotor salient-pole modulator design method is proposed for flux-switching permanent magnet (FSPM) machines by considering both pole number and configuration. With the aid of general air-gap field modulation theory, the influence of rotor pole number is analyzed, and a reliable selection method is proposed to enhance average torque and reduce torque ripple. The result indicates that the rotor modulator with an odd pole number possesses better torque characteristics. Thereafter, the configuration of the rotor salient-pole modulator is investigated and modeled mathematically by the design parameters. Utilizing the proposed design method, an FSPM machine is designed and manufactured. Through the performance comparison and prototype experiment, the proposed design method is verified to be effective in improving the torque characteristics. Without increasing the PM amount, the average torque is enhanced by 14.8%, and the torque ripple is reduced by 93.1%.