Influence of Magnet Arrangement on Performance of Flux Reversal Permanent Magnet Machine

This paper provides a comprehensive analysis of performance difference in the flux reversal permanent magnet (FRPM) machines with various magnet arrangements. The influence of different PM arrangements on working airgap flux density harmonics is firstly revealed. The torque variation against rotor pole number for four PM arrangements is then analyzed. Results show that each arrangement exhibits superiority in different ranges of rotor pole number. In addition, the electromagnetic performances of four PM arrangements with associated optimal rotor pole numbers are compared. It indicates that the FRPM machine, in which four PM pieces are mounted on each stator tooth and two adjacent magnets on different stator teeth are of opposite polarities, offers the highest torque density and the highest efficiency, which makes it promising in low-speed high-torque applications.