Research On PMSM Sensorless Vector Control System

Permanent magnet synchronous motor is widely used in high performance servo drive system because of its high power factor and good speed regulation performance.In the traditional permanent magnet synchronous motor speed control system,the mechanical position sensor is often used to obtain the rotor position.The installation of mechanical sensors will reduce the reliability of the speed control system and increase the cost of products.The position sensorless control technology can just solve the above disadvantages.However,the traditional sensorless control technology is usually aimed at a certain condition in low speed,medium speed and high speed,which cannot meet the requirements of full speed range.In order to solve this problem,this paper focuses on the research of sensorless composite control technology.(1)This paper briefly analyzes and discusses the sensorless control strategy.The pulse high-frequency voltage signal injection method and rotating high-frequency voltage signal injection method in the low-speed section and the model reference adaptive control method in the middle and high-speed sections are studied.The control principle is analyzed,and the mathematical model is deduced.At the same time,the corresponding simulation models are built on the Matlab / Simulink platform for analysis and comparison,and the theory is verified.(2)In view of the limitation of the current sensorless control strategy in the full speed range,a composite control strategy is proposed.The pulse vibration high-frequency voltage signal injection method suitable for the low-speed region and the model reference adaptive control suitable for the medium-high-speed region are combined.The rotational speed switching switch is designed by using the weighted algorithm.The switching function in the weighted algorithm is replaced by the fitted cubic function to realize the transition switching of the two control methods and realize the complementary advantages.The simulation results show that the control method achieves smooth switching in the speed region,reduces the speed and rotor position error when switching,and realizes the control of permanent magnet synchronous motor in the full speed range.(3)The hardware and software platform of permanent magnet synchronous motor control system is built based on the design parameters and control indicators,the CPLD fault protection circuit is designed,and the host computer is developed to realize the remote monitoring of the electronic control system.The related functions of the main modules are tested in combination with the design index.At the same time,the experiments of the pulse vibration high-frequency voltage signal injection method under different rotational speeds and torque conditions are carried out.The experimental results show that the observer in the control method realizes the dynamic tracking of the actual motor speed and rotor position,which verifies the feasibility and effectiveness of the control strategy.