Optimal design of permanent magnet linear synchronous motor for ultra low force pulsations

The inherent drawback of iron-core type permanent magnet linear synchronous motor (PMLSM) is detent force that is dependent on several major factors such as pole-arc to pole-pitch ratio of magnet, slot clearance, and skewing. To minimize the detent force, this paper proposes a structure optimization using the combined computation of two dimensional (2-D) finite element method (FEM) and response surface methodology (RSM). The RSM, that is a collection of the statistical and mathematical techniques, is utilized to predict the global optimal solution based on the FEM calculated results of the detect forces for different combinations of factors. With the help of the combined computation the high capacity iron-core type PMLSM with more than 12000 N propulsion forces only contains less than 3 N detent forces.