关键词: 永磁直线同步电机, 无位置传感器控制, 反电动势积分法, 磁链中值法

Abstract: In order to achieve sensorless operation of surface mounted permanent magnet linear synchronous motor ( SPMLSM) , an open-loop to closed-loop control method was adopted. PMLSM started by open-loop control method after starting positioning, and the angle of the mover was estimated based on the back-EMF integration method. By gradually reducing the primary voltage amplitude to lower the current, the angle between the open-loop current vector and the estimated angle of the mover was observed. When the angle arrived appropriate value, the control was smoothly switched to the closed-loop state for effectively reducing the overshoot of current and speed. The key problems of the observed magnetic flux drift in the low speed domain and stable switching were solved. The effectiveness of the control algorithm was verified based on the PMLSM experimental platform. The results showed the root mean square error of the motion estimation results was 0. 065 rad when the operating speed was 3 Hz. Within this error, the smooth switching was achieved, which verified that the back-EMF integration method could realized sensorless control of SPMLSM in low speed domain.

Key words: permanent magnet linear synchronous motor ( PMLSM ), sensorless control, back-EMF integration method, magnetic flux median method