Application Of High-Order Sliding Mode In Surface-Permanent Magnet Synchronous Motor

A surface-mounted permanent magnet synchronous motor is widely used in the industrial drive system because of its good dynamic performance,high power factor,and simple structure.However,there are still many problems in the drive control technology of surface-mounted permanent magnets synchronous motor,such as the high precision requirement of sensor-less control and the high-performance speed regulation requirement of direct torque control.Because of these problems,this paper has carried out a series of research.This paper introduces the mathematical model of surface-mounted permanent magnet synchronous motor and the basic principle of high order sliding mode control.Firstly,aiming at the problem of high-performance speed regulation in direct torque control(DTC)of surface-mounted permanent magnet synchronous motor,a sliding mode control strategy of no flux link loop space vector pulse width modulation direct torque control(SVM-DTC)for surface-mounted permanent magnet synchronous motor based on a fast super-twisting algorithm(FSTA)is proposed.Based on the original super-twisting algorithm(STA),this strategy introduces the fast terminal sliding mode reaching law(FTSMRL),which solves the problems of slow response and poor antidisturbance caused by the proportion term’s square root the super twisting algorithm.Simulation is built on MATLAB / Simulink platform,and the effectiveness of the proposed strategy is verified by comparing with PI controller,sliding mode controller based on exponential reaching law(SMC),and super-twisting sliding mode controller(STA-SMC).Besides,in the sensor-less control technology,the traditional sliding mode observer(SMO)algorithm is widely used because of its simple structure and strong robustness,but its inherent high-frequency chattering seriously affects the control accuracy of the system.Simultaneously,the sliding mode observer algorithm is a sensor-less control technology based on the total back EMF,challenging to operate at low speed.Therefore,a super-twisting sliding mode observer algorithm with adaptive feedback gain(AFGSTA-SMO)is proposed to solve these problems by combining the super-twisting algorithm with the equivalent feedback principle.In this algorithm,the estimated back EMF is fed back to the estimation of stator current,and an adaptive law is designed to adjust the feedback gain coefficient online to compensate the rotor position,to solve the problem of serious chattering due to too small back EMF when the motor is running at low speed.Simultaneously,considering that there are still many ripple components in the estimation of back EMF,a modified back EMF observer is introduced to filter,and a smoother back EMF signal is obtained,which further improves the sensor-less control accuracy of the system.Simulation is built on MATLAB / Simulink platform,and compared with traditional sliding mode observer algorithm and super-twisting sliding mode observer algorithm(STA-SMO),the effectiveness of the proposed strategy is proved.