Design and Analysis of Two Doubly Salient Permanent Magnet Machines

In order to improve the torque density of doubly salient permanent magnet (PM) machine (DSPMM), two different DSPMMs (topologies I and II) with NdFeB PM materials embedded in the stator yoke are presented, and the working magnetic circuits of both topologies contain the main magnetic circuit and auxiliary magnetic circuit through the magnetic barrier beside the PMs, which can improve the air gap flux density and the torque density effectively. The optimization designs of two DSPMMs are analyzed by establishing the equivalent magnetic circuit (EMC) models at no load and load conditions. Another two traditional DSPMMs (topologies III and IV) are taken as the comparison objects, and the best optimal structure parameters of the four topologies are decided by genetic algorithm. A prototype of topology II is manufactured, and the electromagnetic performances of the four DSPMMs are revealed. It is observed that the electromagnetic performances of topology II analyzed by EMC method are in agreement with the results analyzed by finite element method and test results, and the torque of topology II is larger by 148.1%, 27.72% and 245.5% than that of topology I, III and IV, respectively.