Novel doubly salient permanent magnet machines with partitioned stator and iron pieces rotor

In this paper, novel partitioned stator doubly salient permanent magnet (PS-DSPM) machines with separated PM excitation and armature windings are proposed. Compared with conventional DSPM machines with single stator in which PMs are inserted in the yoke and windings are arranged on the teeth, the proposed PS-DSPM machine has two stators with PMs and windings located separately. Two sets of PS-DSPM machines, i.e., PS-DSPM-I and PS-DSPM-II machines, are proposed based on the conventional DSPM-I and DSPM-II machines in which the PMs are located on the stator yoke with intervals of every number of phases and every stator pole, respectively. The electromagnetic performance including back electromotive force (EMF) and torque characteristics of the proposed PS-DSPM machines are analyzed and compared with those of the conventional DSPM machines based on the optimal designs for the highest average electromagnetic torque by finite-element (FE) analysis in this paper. FE results show that the proposed PS-DSPM-I and PS-DSPM-II machines exhibit 8.49% and 207% higher torque density than the conventional DSPM-I and DSPM-II machines with same copper loss, respectively. The influence of main design parameters on the average electromagnetic torque in the proposed PS-DSPM machines is investigated, together with the conventional DSPM machines. A prototype machine of PS-DSPM-II is manufactured and tested to verify the FE analysis.