Initial position estimation for permanent magnet synchronous motors based on rotor micro-movement

Aiming at the problem that it is difficult for surface permanent magnet synchronous motors to estimate the initial rotor position without position sensors, an initial rotor position estimation method based on rotor micro-movement was researched. By analyzing the current response of the stator windings with extremely low frequency rotating voltage injection, it was concluded that the initial rotor position could be estimated from the current response of the static coordinate system under the motor micro-movement state, and the amplitude of the injected voltage signal could be obtained according to the change multiple of the current response increase, which further improved feasibility and practicality. Finally, the polarity of the rotor could be determined by injecting voltage vectors in positive and negative directions and comparing the current response amplitude. Experimental results show that this method could accurately and effectively estimate the initial rotor position with different load, and the results could meet the requirement of motor start-up. © 2021, Harbin University of Science and Technology Publication. All right reserved.