Research On Control Strategy Of Positionless Sensor For Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors have been widely used as common AC motors in high-performance speed control systems.They have a simple structure,small size,light weight,long life,high torque ratio,high efficiency and high power density are beneficial to the development of the motor system in the direction of small and light weight,high performance,high efficiency and energy saving.This paper takes the permanent magnet synchronous motor control system as the research object,and estimates the rotor speed and position of the permanent magnet synchronous motor without position sensor in real time.The purpose is to reduce the cost of the permanent magnet synchronous motor control system and increase the practicability and reliability of the permanent magnet synchronous motor control system.the first is to study the id=0 vector control strategy of permanent magnet synchronous motor.the improved sliding mode speed controller is used instead PI traditional speed controller.Because sliding mode control itself is a kind of discontinuous switch control,it will make the motor control system appear "buffeting" phenomenon.A new approach law is designed for the sliding mode speed controller in order to reduce the effect of buffeting on the motor system.MATLAB/Simulink simulation results show that the improved sliding mode speed controller can make the system have faster dynamic response and better estimation effect.During the zero-low-speed start-up of the surface-mounted permanent magnet synchronous motor,the motor model is processed into a simple R-L load for the traditional pulse-vibration high-frequency voltage injection method,which makes the estimation of the rotor information of the motor inaccurate and will use filters several times to extract the rotor information.This paper first replaces the traditional PI speed controller with the improved sliding mode speed controller.The magnetic pole of the rotor is judged by the current signal of the estimated synchronous rotation coordinate d' axis,and the output signal of the estimated synchronous rotation coordinate and q' axis is multiplied by the same frequency as the injection voltage.The triangular sinusoidal function signal is extracted by low-pass filter,which eliminates the use of band-pass filter and improves the control efficiency.MATLAB/Simulink simulation results show that the improved pulse vibration high frequency voltage injection method can make the motor control system faster dynamic response and stronger anti-interference ability.By replacing the traditional PI speed controller with the improved sliding mode speed controller and replacing the PI link of the traditional model reference adaptive method,the system has better rotor speed estimation effect.At the same time,the anti-interference ability and tracking precision of motor control system are improved.MATLAB/Simulink simulation results show that the improved dual-slip model reference adaptive method not only has a strong ability to suppress disturbance,but also can accurately estimate the rotor information and better dynamic performance.