Torque characteristics analysis of dual-airgap spoke-type permanent-magnet Vernier machine considering pole ratio effect

摘要

The ratio between rotor poles and stator winding poles plays a deciding role in the performance of Vernier machines. Therefore, it is very important to analyze the effect of pole ratio on the electromagnetic torque performance of permanent-magnet Vernier machine. Dual-airgap spoke-type permanent-magnet Vernier machines (PMVMs) are becoming popular due to their low speed and high torque characteristics in the direct drive applications. This paper presents the effect of pole ratio on the performance of dual-airgap spoke-type PMVM. The performance parameters such as torque ripple, average torque, torque density and efficiency are analyzed by the variation of design parameters such as stator and rotor pole numbers and winding pole numbers, while keeping the same outer dimensions, similar magnet volumes and same airgap lengths in all the models. The electromagnetic torque characteristics are analyzed with the variation of pole ratios until the model reaches the maximum torque performance at a specific combination of rotor and stator poles. 2D-finite element method is used to analyze the performance of the model and verify the effect of pole ratio on the torque performance of dual-airgap spoke-type PMVM.