Comparative Study of the Π-Core Doubly Salient PM Machines Having Different Stator Core Segments and Armature Winding Configurations

This paper discusses the influence of stator iron core shape and armature winding distribution on the torque characteristic of the FI-core doubly salient permanent magnet machines (II-core DSPMMs) in detail. In this paper, the structures of four different motors are firstly described in detail. Thereafter, by right of the finite element technique, all investigated machines are optimized by parametric scanning for maximum torque output for a fair comparison. Then, some key performances are compared and discussed, for example, open-circuit phase flux linkage, phase back-EMF, cogging torque, and electromagnetic torque. The results show that the design of the focusing tooth (FC) is similar to the dual armature (DA) in terms of boosting the output torque of FI-core DSPMM. Compared to the conventional FI-core DSPMM, the FI-core DSPMM with FC and DA design (II-core FC-DA-DSPMM) has a sharp average torque increase of124.7%, and its torque ripple decreases from 4.8% to 2.8%. In addition, the FI-core FC-DA-DSPMM has better PM utilization and inherent fault-tolerant feature.