Research on Air-Gap Field Modulation Effect of Torque Enhanced Hybrid Permanent Magnet Motor

In order to further enhance the torque and improve the utilization of permanent magnet, this paper proposed a new hybrid PM motor with spoke-type and consequent-pole structure (HPM-SCP). The air-gap field modulation effects (AFME) in the HPM-SCP motor are researched. By quantifying the contributions of the various air-gap flux density harmonics to the torque components and torque fluctuation, the working harmonics and the dominating harmonics that contribute to torque production are analyzed. In addition, a comprehensive comparison of the electromagnetic characteristics of HPM-SCP motor and a traditional HPM machine is conducted. It identifies that in the HPM-SCP motor, the magnetic field modulation effects can be generated significantly thanks to the spoke-type and consequent-pole structure. Then the influences of the key dimension parameters on AFME for torque performance of the HPM-SCP motor are evaluated. Finally, the reliability and effectiveness of theoretical analysis and FE simulation are verified by experiments on an HPM-SCP prototype.