Comparative Analysis of Doubly Salient Special Machine and Flux Switching Machine with PMs in Stator

A comparative analysis of a doubly-salient special machine with permanent magnets (DSPM) in the stator and a traditional flux-switching permanent magnet machine (FSPM) has been presented in this paper. A topology of 12 concentrated coils, 12 PMs, and a reluctance-type rotor with 10 pole protrusions of identical design matrices have been considered in this analysis. The proposed DSPM, which has toroidal windings in the stator segments separated by PMs of opposite polarity, generates flux in the circumferential direction. In contrast, the FSPM has stator segments separated by PMs, but the coils are wound around the teeth of two adjacent stator segments to generate flux in the radial direction. Despite the doubly salient structure, these two machines behave as non-salient machines electrically. The flux linkages with coils, self-inductances, and mutual inductances in these two machines differ greatly. Despite the presence of flux doubling effect, flux weakening and higher speeds in the proposed special machine are achievable easily, whereas, in FSPM, the presence of flux linkages due to PMs is significantly high, making it difficult to weaken the flux compared to the proposed DSPM. A detailed analysis presented in this paper has revealed that the proposed special machine is superior compared to FSPM in achieving high speeds in the field weakening or constant power regime and is highly suitable for electric vehicle traction applications.