Research Of Sensorless Control System Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor (PMSM) are popular in high performance speed regulating system mainly due to their high efficiency, high power density, simple" control. But in the process of control running, PMSM usually need a mechanical sensor to obtain accurate rotor position information. It increased the system cost and volume, reduced the system reliability. In order to solve those above problems, sensorless control technology was put forward and had received a widespread attention. Owing to pulsating high frequency voltage injection method can estimate rotor position at zero speed to a wide range and it is precision to location estimation and insensitive to the motor parameters, so it has been the research focus for scholars at home and abroad.The goal for this paper is to design a high frequency injection method of vector control system. Devoted to the theoretical research and computer simulation of control algorithm, and made every effort to provide theoretical guidance for practical systems. The main work arrangement is as follows:First of all, this paper discussed the detecting method and implementation approaches for traditional initial position and runtime position of rotor, analyzed the principle for pulsating high frequency voltage injection method to implement the rotor position estimation, theory deduced and simplified the high frequency current response and related information, detailed the information extraction process of rotor position.Secondly, built PMSM vector control simulation system based on pulsating high frequency voltage injection method in the MATLAB/Simulink, tuning the controller parameters and structure, carry on the analysis of static and dynamic tracking performance.Thirdly, considering the shortage of the traditional PI speed controller, introduced the sliding mode controller to the pulsating high frequency voltage injection method system. This method improved the system of large amount of overshoot, slow response, insufficient anti-interference ability, but also increased the responding speed.Fourth, this paper analyzed the influence of stator resistance, speed EMF and injected high frequency signal to the position estimating errors, studied the mechanism of error generating and reducing routine.Finally, launched simulation for the method and information mentioned in this paper by the MATLAB/Simulink. The results showed that the pulsating high frequency voltage injection method system based on SMC controller has improved the detection precision of the rotor position. Otherwise, it has strong anti-jamming capability and the speed can adapt to a wide range. The results also confirmed the factors influencing rotor position error.