Study Of Sensorless Control System For PMSM Based On Sliding Mode Observer

Sensorless control of permanent magnet synchronous machines(PMSMs) was a hot issue in the area of electrical machine controls in recent years. There are already a lot of sophisticated control strategies and algorithms have been proposed and applied, but there is no control strategy that can be used to control the PMSM precisely among the whole speed range. Therefore, according to the requirements of the practical application, proper integration of control strategies and sensorless algorithms is proposed to realize a complete and reliable sensorless operation at full speed range. So far, the sensorless control system of PMSM is mainly used in various types of compressors and pumps occasions, such as washing machines, air compressors, etc. Characteristics of these applications is that most of the time machine running in the main section of the high-speed, high-speed section efficiency have higher requirements, and the speed performance of low-speed section is not particularly required. Therefore, for such applications, the best control strategy is using a simple and reliable method for the motor to accelerate from rest to a working speed range, then using a precise position-control strategy to maintain stable and efficient operation of the motor. On the basis of sensorless control method based on sliding mode observer, this paper propose a simple and reliable method of start and switching state, which can achieve senseless operation in wide speed range. The main contents of this paper are as follows:Firstly, this paper describes the development process of the AC servo technology, focusing on the development process and the status of permanent magnet synchronous motor without position sensing control technology. Then the mathematical model of PMSM, the principle of vector control and SVPWM are analyzed in detail. And a vector control(control) model of PMSM speed control system adopting strategy is established in Matlab / Simulink, which is simulated and analyzed in the simulation environment.Secondly, the principle of sliding mode control with variable structure is briefly introduced. And the senseless control system based on sliding mode observer is established, which proposes a current loop running start method in senseless control. Then the corresponding model is established in Matlab / Simulink for simulation, thus the feasibility of position senseless control system can be verified in theory.Thirdly, the test platform of PMSM control system is built, And the basic vector control performance and senseless control operation is experimented on the test platform.Finally, the experimental results are analyzed in detail, which indicate that the proposed senseless control method is feasible. And the system has strong practicality and robustness and verifies the correctness of the theory and simulation.