Performance Comparison of Stator Partitioned Doubly Salient Permanent Magnet Motors with Diverse Number of Permanent Magnets

A comparison of the performance of the stator partitioned doubly salient permanent magnet (PS-DSPM) motors exhibiting a diverse number of permanent magnets (PMs) is carried out in this paper. For the PS-DSPM motors investigated here, the quantity of PMs needs to exist in pairs and the radial axis of each PM must align with the symmetry axis of two adjacent stator teeth. So the available PM number for the PS-DSPM motors with twelve stator slots are 2, 4, 6, and 12. For a fair comparison, the PS-DSPM motors with 2, 4, 6, and 12 PMs are designed to get larger output torque based on a parametric analysis optimization technique in the case of identical copper loss and envelope dimensions. Thereafter, some key electromagnetic properties of these PS-DSPM motors are compared. The results show that by changing the number of PMs from traditional 4 to 2, 6, and 12, the torque ripples of PS-DSPM motors are reduced to varying degrees. Especially, when changing the quantity of PMs in PS-DSPM motor from 4 to 6, its torque ripple is sharply decreased from 155.37% to 19.47% and the corresponding average torque also increases by 25.2%.