Design and Optimization of Slotless Permanent Magnet Linear Synchronous Motor With Short Primary and Long Secondary Structure

This paper explores the feasibility of an intuitive improvement thrust force fluctuation and detent force for the existing permanent magnet linear synchronous motor (PMLSM) by slotless structure, so as to better adapt to the high precision servo system. The thrust force fluctuation and detent force of the motor is related to the key design parameters, which is the motor structure, slot size, and PM dimensions. Firstly, according to the working principles and design requirements, a 30N slotless PMLSM is designed, and the key parameters relating to thrust force are analyzed and discussed. Meanwhile, the main dimensions of the slotless PMLSM are optimized by Taguchi method, such as PM magnetization height, PM longitudinal length, and slot size. Then, base on the optimization dimensions and structure of the motor, the numerical method is used to analyze and calculate the performance parameters of the slotless PMLSM. Based on the analysis of results, the optimized slotless PMLSM compares electromagnetic thrust force fluctuation and detent force with a slotted PMLSM. The thrust force fluctuation of the slotted PMLSM is 9.29 times that of the optimized slotless PMLSM. However, the detent force of the optimized slotless PMLSM is only 7.04 % of that of the slotted PMLSM. Finally, under the same conditions, the performance parameters of the optimized slotless PMLSM with load is verified by experiment. Through analysis of the results, the experimental thrust force is 3.01% higher than that obtained by numerical method and 4.0% higher than the rated value. Meanwhile, the experimental phase EMF is 8.11% higher than that of numerical method. These study not only meets the design requirements, but also verifies the correctness and rationality of the design and analysis method.