Permanent Magnet Synchronous Motor High-Frequency Signal Injection Initial Position Self-Detection And Sensorless Operation

Permanent Magnet Synchronous Motor(PMSM)has greater starting torque,higher efficiency,lower losses and temperature rise compared to asynchronous motors,and it is smaller,lighter,and has a wider range of efficient operation,so it is favored by various industries and is widely used.In the modern servo control system control motor algorithm,obtaining the rotor position information of the permanent magnet synchronous motor is an indispensable part of the closed-loop control system,using such high-precision position sensors as resolver and encoder can ensure better control of the motor,real-time and high-precision tracking of the rotor position,which can improve the control of the motor torque and speed and suppress the output current peak and noise.For example,for some small and light weight motors,blind installation of position sensors will lead to increased system losses;for some motors used in harsh environments and under complex working conditions,position sensors are easily damaged.In view of the above problems,this thesis will study the position sensorless control technology from two speed domains,zero low speed and medium high speed,as follows:Firstly,the control principle of high-frequency rotating voltage injection is introduced,its processing of high-frequency current is analyzed,the expression of rotor position estimation error is derived,and the control system block diagram is constructed on this basis,and a Simulink simulation model is built in MATLAB based on the control system block diagram for the speed,rotor position,and electromagnetic torque curve,and the rotating high-frequency The limitations of the voltage injection method are summarized.Secondly,a new pulse-oscillation high-frequency voltage injection method is proposed for the traditional pulse-oscillation high-frequency voltage injection method to detect the rotor position with large estimation error,poor dynamic performance and weak robustness,considering the combination of the current response of the cross-axis and the straight-axis,taking the cross-axis current as the regulation signal at the same time,eliminating the low-pass filter to extract the cross-axis fundamental frequency current feedback signal in the traditional pulse-oscillation high-frequency voltage injection method,using the cross-axis current The rotor position information is extracted from the phase-locked loop system,and a method to determine the rotor pole polarity is proposed for the rotor position convergence problem.It is demonstrated through simulation experiments that the new pulsed high-frequency voltage injection method results in more accurate rotor speed estimation,smaller rotor position estimation error,and reduced torque pulsation.Thirdly,a new observer based on the second-order generalized integrator is proposed to address the jitter of the traditional sliding mode observer system.The new observer combines the sliding mode observer,adaptive filter and phase-locked loop system to reduce the system jitter phenomenon and improve the system position estimation performance and dynamic performance.The traditional phase-locked loop structure is improved to make the system stable at all equilibrium points and overcome the problem of sudden increase in rotor position estimation error when the traditional phase-locked loop system is faced with the change of motor speed direction.The experimental results show that the rotor position detection research method based on the new observer has a strong comprehensive performance,and the rotor position estimation and rotor position estimation are accurate,overcoming the problem that the rotor position estimation error of the traditional control method increases suddenly when the motor steering changes abruptly.