Analysis of the Optimal Slots and Poles Combination for Reducing Cogging Force in Permanent Magnet Linear Motor

Permanent magnet linear motors are extensively used in high-performance applications. However, in slotted permanent magnet linear motors, there exists detent force which may cause noise and vibration. It can be divided into two components: the cogging force and the end force. In this paper, being based on Fourier expansion, the cogging force was analyzed, and its analytical expression was got. On that basis, the optimal method was presented to reduce the cogging force. And the simulated and experimental results show that the permanent magnet linear motor cogging force can be reduced effectively when the pole number and the slot number are co-prime. The results have important significance for reducing cogging force on PMLM design.