Torque Density and Magnet Usage Efficiency Enhancement of Sandwiched Switched Flux Permanent Magnet Machines Using V-Shaped Magnets

This paper proposes a novel sandwiched switched flux permanent magnet (SSFPM) machine using V-shaped magnets for maximizing output torque and improving magnet usage efficiency. The operation principle of conventional 6/10-stator/rotor-pole SSFPM machine is firstly described. Such SSFPM machine and a novel one with V-shaped magnets are optimized and then compared with the conventional 12/10-stator/rotor-pole SFPM machine by two-dimensional (2-D) finite element analysis (FEA). It is found that the SSFPM machine with V-shaped magnets exhibits higher torque density and higher magnet usage efficiency. In addition, the influence of step-skew angle on the torque ripple suppression is investigated in the SSFPM machine with V-shaped magnets. The FEA predicted back-EMF, cogging torque, torque-current characteristic are validated by experiments on the prototype machines.