Sandwiched Flux-Switching Permanent-Magnet Brushless AC Machines Using V-Shape Magnets

Abstract

Conventional flux-switching permanent-magnet (FSPM) brushless machines have emerged as an attractive machine type by virtue of their high torque densities, simple and robust rotor structure, and the fact that permanent magnets and coils are both located on the stator. In order to improve the torque density, the sandwiched FSPM (SFSPM) machine has been proposed in which two PM pieces are sandwiched in one stator pole, and V-shape magnet is adopted to enhance the PMs usage efficiency. Finite element method is employed to compare the performance of a conventional 12/10-pole FSPM machine topology with that of V-shape magnet SFSPM machine topologies, in terms of field distribution, flux-linkage, back EMF, and output torque. It shows that the average torque of V-shape SSFPM is increased about 25% compared with conventional FSPM machine, and meanwhile, the magnet usage efficiency has been increased by 29.4%. A variation in stator and rotor pole combination of the proposed topology is analyzed in order to maintain a sinusoidal back- EMF waveform and reduce the torque ripple. Finally, efficiency of the machine is simulated to evaluate the proposed system.