Research On Sensorless Control Of PMSM Based On Pulse Vibration High Frequency Injection Method

Permanent magnet synchronous motor（PMSM）is widely used in various engineering fields due to its superior dynamic performance and small size,and the research on its control system has increasingly become a hot topic in today’s industry and scientific research fields.Due to the detection of the rotor position and speed,the system often needs to be equipped with corresponding sensors,which makes the motor larger in size,worse in performance,and higher in cost.Therefore,the research on sensorless vector control technology has emerged as the times require.This thesis mainly takes the zero-low speed condition of the motor as the starting point,and conducts an in-depth study on the pulsed high-frequency voltage injection method（HFPVI）.Firstly,this thesis briefly expounds the classification of PMSM in structure,and deduces its basic mathematical model and coordinate transformation theory in detail.At the same time,it summarizes the basic principle and realization process of PMSM vector control technology.Secondly,starting from the salient pole effect of the motor itself,the theoretical basis of HFPVI is expounded.Combined with the research difficulty,how to make the estimation accuracy of speed and rotor position more accurate,two kinds of factors that affect the control accuracy,namely system hardware and software parameter settings,are analyzed.A detailed analysis is carried out from the perspective of the current detection link in the system hardware.Theoretical analysis shows that the gain deviation in the current detection link will generate a second harmonic error.Therefore,the second-order generalized integrator method（SOGI）is studied to filter out this harmonic,and the corresponding test module is built in MATLAB/Simulink to verify its effectiveness in filtering higher-order harmonics of the signal.At the same time,a control system simulation platform with HFPVI as the basic framework is built in MATLAB/Simulink,and the effectiveness of the system in sensorless control is tested by simulating the second harmonic error input.Finally,the double filter compensation method is also studied for the second harmonic error.The difference from the second-order generalized integrator method is that the double filter compensation method has two sets of filtering devices,one is to extract the information of the position detection error link,and the other is to detect the error information of the second harmonic.Then,the information in the first set of devices is compensated by the detected result,so as to achieve the purpose of eliminating the second harmonic error.The filter test model and the system simulation model were built in MATLAB/Simulink to verify the excellent performance of the method in eliminating the second harmonic problem of the system.Compared with the traditional HFPVI,the improved HFPVI based on the second-order generalized integrator method and the double filter compensation method has more obvious advantages in controlling the overshoot and steady-state performance of the motor speed.Sudden addition of a given simulation test,the motor speed control is more responsive and robust.The simulation experiment verifies the effectiveness and reliability of the two methods in solving the traditional HFPVI control defects.