Single current loop starting and closed loop transition

 of sensorless PMSM control

 

 

ZHU Wanping, SUN Yaocheng, HU Qinfeng, XUE Wenbin

 

(School of Autonation, NanJing University of Aeronautics and Astronautics, NanJing 210016 China)

 

 

Abstract: Aiming at the problem of permanent magnet synchronous motor(PMSM) sensorless starting at low speed, the method of openloop speed and closed current loop was researched, which drives motor by given current vector. After the analysis of the transition from single current loop to speed closed loop control based on the startup of single current loop control, a method that daxis current control was brought to increase “torquepower angle balance” area was presented to optimize startup and transition. The current and power angle changes of transition in the proposed method were tested by digital AC control system using DSP. The results indicate that the proposed method is feasible to start and switch, the motor can start smoothly from zero speed. The current and power angle changes of transition are decreased rapidly, and the transition from single current loop to speed closed loop is smooth. Finally, the motor can be accelerated to normal operating mode.

 

Key words: sensorless; permanent magnet synchronous motor(PMSM); transition; startup