A New Flux Reversal Motor With Slot and Tooth Permanent Magnets

Abstract

This article proposes a new consequent-pole (CP) flux reversal permanent magnet (FRPM) motor with homopolar PMs parked in the stator slot openings and between the wound poles' teeth. The proposed PM pattern offers an effective PM usage and lowers the effective armature air-gap length while increasing the output torque. The operating principle of the motor is analysed using a flux modulation theory (FMT) and the predominant harmonics of the air-gap flux density are unveiled. Furthermore, the proposed structure is comparatively analysed with a CPFRPM and a conventional FRPM (CFRPM). These structures are optimised with a genetic algorithm, and by using the finite element analysis (FEA), the no-load and full-load performances are studied. Thanks to effective PM placement, the torque density is improved by 65% and 29% compared to the CFRPM and CPFRPM, respectively. PM demagnetisation, along with a thermal analysis, is developed to guarantee that the PMs are not prone to demagnetisation. A comparative study is also performed to highlight the outperformance of the proposed structure among the stator-PM motors. Eventually, the motor is prototyped and tested to validate the FEA predictions.