Research On Position Sensorless Control Technology Of Permanent Magnet Synchronous Motor Based On High Frequency Injection

Permanent magnet synchronous motors(PMSM)have gradually become the first choice in motor control systems due to its simple structure,high effciency,and easy access to speed control.Commonly in the motor control system,rotor position and speed feedback is indispensable,which is usually realized by position sensors,but in some special cases,position sensors have limitations,so sensorless control technology arouse people’s interest.In this paper,the IPMSM is taken as research object,and sensorless control algorithm based on the high-frequency injection scheme is deeply researched.First,the physical structure of PMSM is discussed,and the mathematical model in the d-q axis is derived through transformation theory.On the basis of the fundamental mathematical model,the PMSM high-frequency mathematical model is established through analysis and simplification,which provides a theoretical reference for the high-frequency-injection method.Then the analysis of two high frequency voltage injection are elaborated,not only introduced the realization principle,but also the calculation formula of high frequency current response,rotor position error extraction method and the realization principle of the rotor position are analyzed.To get free from the use of filters and simplify processing process,a high-frequency square wave injection method is studied to realize the sensorless control on the IPMSM.To solve the problem that estimated initial position of the rotor has multiple values,a method using the salient pole saturation effect is proposed to realize the initial position identification of the rotor,the experimental procedures are described in detail,and the effectiveness of the method is proved by simulation experiments.Finally,on the PMSM experimental platform,the initial position estimation of the rotor using high-frequency square wave voltage injection method is verified through experiments.