Design of PM Linear Synchronous Motor With Chamfered Teeth for Reduced Detent Force Considering Modular Connection

This paper presents the design of the detent force reduction in the chamfered tooth permanent magnet linear synchronous motor (PMLSM). In PMLSMs, in addition to the cogging force characteristic, there is an additional end force at the longitudinal end. The sum of these cogging and end forces is called the detent force, and in a typical PMLSM, auxiliary teeth are designed to reduce this detent force. However, the design of the auxiliary teeth can increase the weight of the motor, degrade the acceleration and deceleration performance, and cause additional iron losses at the end. The detent force reduction with the tooth chamfering method was verified by PMLSM with 8 pole and 8 slot. The characteristics of the cogging force are analyzed for tooth chamfering shape per slot, including the left, right, and both chamfering. The cogging force per slot was analyzed according to the chamfer geometry, and the results showed that there is a phase shift in the cogging force of individual slots depending on the chamfer geometry. Since the phase shift of tooth chamfering shape increases the total cogging force and the phase of the end force and the total cogging force is opposite each other, the detent force can be reduced by this method. Under certain conditions, the detent force was reduced by 81% compared to unchamfered model. In addition, in order to improve the user’s design flexibility and reduce the cost of mass production, the detent force characteristics considering modularization were investigated and verified through prototype manufacturing and experiments.