Zero Low Speed Control System Of Permanent Magnet Synchronous Motor Based On High Frequency Signal Injection

The accurate extraction of rotor position information is very important to the operation of the control system of permanent magnet synchronous motor(PMSM).Sensorless control has important application value because it not only avoids the increase in cost and volume of the control system caused by using a position sensor,but also does not limit the motor’s application.At zero low speed,the high frequency pulse injection method needs to use the salient pole saturation effect of the motor.Based on the vector control strategy with the direct axis current equal to 0,the salient pole saturation effect generated by the high frequency pulse vibration injection method is used to extract the rotor position information.However,the extracted rotor position information is affected by the inverter dead zone,motor parameter error and other factors,which superposition the high order angular frequency harmonics and reduce the control accuracy.In this thesis,a second order generalized integrator is designed to extract a specific frequency signal,filter out the higher harmonics superimposed in the rotor position information,and make the estimated speed and position more accurate.This thesis designs an active disturbance rejection controller to reduce the high overshoot caused by PI controller,and optimizes the structure of the active disturbance rejection controller to simplify the controller design.The active disturbance rejection controller has stronger robustness,which can reduce the fluctuation of rotor position,improve the stability of the system operation,and further improve the accuracy of the high-frequency pulse vibration injection method.Surface PMSM was selected in both experiment and simulation,and simulation analysis was carried out on several operating states of the traditional motor,such as double closed-loop combined magnetic field oriented control and sensorless control based on high-frequency pulse vibration injection under sudden loading.The experiment built an experimental platform for PMSM control system by combining the drive board and motor,using the minimum system board of DSP as the control board.The control program was written by CCS6.0 software,and the high frequency pulse vibration injection method before and after the improvement was analyzed respectively under different given speed.In conclusion,the PMSM control strategy combined with the second-order generalized integrator and the active disturbance rejection control method can effectively improve the position signal extraction accuracy of the high-frequency pulse vibration injection method.The improved method can not only improve the control accuracy of the system,but also maintain the stability and reliability of the control system.