Torque Analysis and Improvement of Single-Phase Asymmetric-Stator-Pole Doubly Salient Permanent Magnet Machine

Doubly salient permanent magnet machine (DSPMM) has received extensive attentions recently due to its simple structure, high reliability, high torque density, etc. An improved 4/4 stator/rotor single-phase asymmetric-stator-pole DSPMM is proposed in this paper. First, it has investigated the topologies and operating principle based on torque expression and graphical description. Then, the effect of key structure parameters on torque is studied based on the 2-D finite-element algorithm. And then, comprehensive comparison on electromagnetic torque for the original and new machines is made. Finally, one prototype for the improved structure is manufactured and tested. It indicates that lower cogging torque, lower torque ripple, and stronger starting capability can be obtained by the improved structure. The theoretical results are well validated by comprehensive experiments.