Permanent Magnet Shape Using Analytical Feedback Function for Torque Improvement

This paper proposes a new design method for surface-mounted permanent magnet machines. The key to the proposed method is that all rank harmonics are introduced to the permanent magnet for torque improvement. The proposed method can offer a variety of magnet topologies by injecting various harmonics into magnets, and these magnet topologies are subsequently analyzed to select the best one. To find the optimal torque output requires investigating the effect of all rank harmonics on the average torque and the torque ripple, and then determining the optimal harmonic combination. The results show that the fundamental, third and fifth harmonics, make great contributions to improving torque quality, while the seventh harmonic and those with higher orders are insignificant for torque improvement. Finally, a prototype, which employs the proposed method, is measured for validation.