Design and Analysis of a Novel Hybrid Rotor PM Machine Considering Negative Torque Ripple Contribution

This article proposes a novel hybrid rotor flux-switching permanent magnet (PM) machine with a low torque ripple. The rotor of this machine is composed of inverted T-shaped PMs and surface-mounted PMs and the rotor teeth of the inverted T-shaped PM and the surface-mounted PM are designed with a modified shape. Compared with the conventional inverted T-shaped PM machine, the hybrid PMs arrangement of the proposed machine introduces additional air-gap flux density time–space harmonics based on the flux modulation principle. Especially, these harmonics contribute to negative torque ripples and further counteract the positive torque ripple harmonics to suppress total torque ripples. Furthermore, the feasibility of the proposed machine is verified by comparing and analyzing the electromagnetic and mechanical performances of the conventional machine and the proposed one. Finally, a prototype was fabricated to verify the effectiveness of the proposed machine.