End Force Analysis and Optimization of Permanent Magnet Linear Synchronous Motor Based on Chamfered Auxiliary Teeth

In this paper, the end force caused by the finite primary length of permanent magnet linear synchronous motor (PMLSM) is analyzed and minimized with the chamfered auxiliary teeth. Firstly, the end force is calculated as the sum of the left-end and right-end forces obtained by the finite element method, and then the conditions satisfied to simultaneously weaken the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2^{\text{nd}}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4^{\text{th}}$</tex> harmonics of the end force are derived. Secondly, the influence of chamfer dimensions of the auxiliary teeth on the end force is analyzed. After that, the optimal length of the primary iron is calculated based on the phase difference between the left-end and right-end forces. Thirdly, with the optimal chamfered auxiliary teeth by above fast optimization method, the peak value of the end force for a 6-slot 5-pole PMLSM can be reduced from 4.45 N to 0.16 N.