Reduction of Radial Electromagnetic Force Waves Based on PM Segmentation in SPMSMs

Electromagnetic vibration is excited by the electromagnetic force waves generated by the air-gap magnetic field acting on the machine core. In this article, a fast and accurate calculation method of radial electromagnetic force density of surface-mounted permanent-magnet synchronous motors (SPMSMs) is proposed, and the radial force density including amplitude, frequency, and order is obtained. Comprehensively considering that the effect of the PM segmentation on electromagnetic force waves, cogging torque, and the no-load back electromotive force (back EMF), the optimal determination of the number of PM segmentation in different slot-pole combinations of SPMSMs is summarized, and six slot-pole combinations of SPMSMs with 6p36s, 4p36s, 6p9s, 8p9s, 8p12s, and 10p12s are calculated and analyzed to verify the universality of the conclusions, which lays a theoretical foundation for the weakening of the radial electromagnetic force.