Cogging Torque Reduction for a Novel Disk Transverse Flux Permanent Magnet Motor

Transverse flux permanent magnet motor (TFPM) and axial flux permanent magnet motor (AFPM) are both new types of highperformance motor and have been used in various applications. However, both of them are constrained by the cogging torque that leads to a large torque ripple. In view of a novel disk transverse flux motor (DTFM) which combines the characteristics of both transverse flux and axial flux permanent magnet motor, the research on its cogging torque is proceeded in this paper. First of all, the cogging torque of the DTFM is analyzed and expanded as the form of the Fourier series. In order to reduce its cogging torque, a method of unalignment of stator disks is introduced. Then, an analysis method based on Schwarz-Christoffel mapping (SC-based method) is extended to calculate the cogging torque of DTFM with unaligned stator disks. The cogging torque of the DTFM with unaligned stator disks can be reduced by 83% compared with the initial DTFM. Finally, a prototype DTFM with unaligned stator disks is manufactured and tested.