Detent Force Reduction by Positional Shifting of Permanent Magnets for a PMLSM Without Compromising Thrust

Abstract

Detent force is caused by the interaction of a permanent magnet's flux with an armature's teeth even in the absence of armature excitation. It produces unwanted vibrations and hinders precise motion control of Permanent Magnet Linear Synchronous Motor (PMLSM). Reduction of detent force is still a challenge as it is always accompanied by reduction in the desired thrust. In this paper, a method to reduce the detent force without compromising thrust is proposed. By adjusting the position of the mover magnet with simultaneous re-arrangement of coil phases, significant reduction in the detent is achieved with negligible effect on thrust. Finally, simulation and prototype measurements were used to depict the usefulness of the proposed method.