Field weakening performance of hybrid permanent magnet synchronous motor
CHEN Min xiang1, WANG Shuai1, WANG Zong pei2

(1.College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China;
2.Zhuhai Motion Control Motor Co., Ltd., Zhuhai 519000, China)


Abstract: Aiming at solving the problem of the poor field weakening performance of traditional permanent magnet synchronous motor, hybrid permanent magnet synchronous motor was presented. Through studying structure of traditional permanent magnet synchronous motor, the cause of field weakening difficult of traditional permanent magnet synchronous motor was armature potential far less than rotor excitation magnetic potential was obtained. Permanent magnet expenditure of hybrid permanent magnet synchronous motor was less, so its rotor excitation magnetic potential was smaller. The air gap of hybrid permanent magnet synchronous motor was smaller and synchronous inductance was bigger, so the ratio of short circuit current and rated current was smaller. Judging field weakening performance of permanent magnet synchronous motor by the ratio of short circuit current and rated current was introduced, and better field weakening performance using hybrid structure was obtained. Additional closed loop method based on direct axis current negative control was adopt to conduct field weakening experiment of traditional permanent magnet synchronous motor and hybrid permanent magnet synchronous motor. The field weakening speed expansion ratio of hybrid structure motor was 2.63 times that of the traditional structure. The results indicate that the field weakening performance of permanent magnet synchronous motor can be effectively improved by using hybrid structure.

Key words: hybrid permanent magnet synchronous motor; short circuit current; field weakening control