Analysis and Calculation of the Normal Force Fluctuations of Permanent Magnet Linear Synchronous Motor

Abstract

Permanent Magnet linear synchronous motor (PMLSM) exist the problem of normal force fluctuation, especially in the servo feeding system of high-precision CNC machine tools. The normal force fluctuation can cause the feeding table in vibration and produce resonance with other moving components of the servo feeding system. It is produced by normal electromagnetic force wave acting on iron cores of PMLSM. In this paper, the analytical expression of normal electromagnetic force wave of single-side PMLSM is deduced with the method of MMF (magnetomotive force) magnetic permeance. And based on this, analyze composition and classification of the force wave component; the further study of the influences to the force wave order and amplitude when the coefficients of the electric machine are changed is done. Then, base on a PMLSM with 6 poles and 36 slots, the results of analytic calculation are accordant with the FEM simulation ones. These results prove the analytical expression is correct and accurate.