Reduction of the Detent Force in a Flux-Switching Permanent Magnet Linear Motor

In this paper, the detent force caused by the end effect in a flux-switching permanent magnet linear motor (FSPMLM) with six slots and five poles is investigated and reduced by two different methods. First, the detent force is diminished by adjusting the position of end teeth of primary side and injecting compensation current into compensation windings wound around the end teeth. Based on the linear relationship between compensation current and compensation force, the proper compensation current is derived and analyzed. Then, to avoid the magnetic coupling between compensation windings and phase windings, a novel compensation module with independent magnet circuit is presented and attached to the primary side of FSPMLM. Third, the two detent force reduction methods are compared with each other, and the compensation module is proved to be more effective. Finally, a prototype of FSPMLM with compensation modules is manufactured and tested to validate the proposed compensation method.