A Novel Flux Switching Permanent Magnet Machine Based on Quantitative Stator Permeance Construction Approach

Benefited from flux modulation effect, flux switching permanent magnet (FSPM) machine can exploit multiple air-gap flux density harmonics to contribute the average torque, which is promising for ship propulsion, wind generation, and other high torque density applications. However, lacked of the dedicated design approach, the existing FSPM machine generally cannot make full use of the air-gap flux density harmonics. This paper is devoted to propose a quantitative stator permeance construction approach to achieve the maximum average torque. The proposed approach is developed by discretizing the stator permeance along the circumferential direction and evaluating the polarity of back electromotive force (EMF) contributed by each stator permeance unit, then designing the corresponding stator permeance structure to strengthen the back EMF contribution having the same polarity while restrict the back EMF contribution having the reverse polarity. Based on the proposed design approach, a novel FSPM machine with non-uniform auxiliary teeth is presented, where the electromagnetic performances are compared with the regular FSPM machine by finite element analysis (FEA). It indicates that the torque density of proposed machine could achieve 15.1 Nm/L under electric loading of 160 A/cm, which is 17.7% higher than regular counterpart. Finally, a prototype is fabricated and tested to verify the theoretical analysis.