Optimal design of auxiliary poles to minimize detent force of permanent magnet linear synchronous motor

Abstract

sThe problem in improving the high positioning precision of permanent magnet linear synchronous motor (PMLSM) is the large detent force that is caused by the attraction bet ween the permanent magnet (PM) and the iron core without input current. This detent force can be divided into two components: the slot effect and the end effect. In this paper we propose a novel method to reduce the detent force by employing the optimal designed auxiliary poles. To investigate the characteristics of the detent force of PMLSM with auxiliary poles, the width, position, and height of auxiliary poles are chosen as the opt imal factors and the two dimensional (2-D) finite element method ( FEM) is used to predict to the values of detent force with different combinations of these three factors. And then the structure of auxiliary poles is optimized by the response surface method (RSM) through the fractional factorial design (FFD). Finally, the effectiveness of our proposed technique is verified b y both the numerical calculations and experimental results.