Research On Direct Torque Control Of Permanent Magnet Synchronous Motor Based On Super-twisting Sliding Mode Control

Direct torque control(DTC)of permanent magnet synchronous motor(PMSM)has the advantages of simple control structure,fast dynamic response,less parameter dependence and strong robustness,but it also has the disadvantages of large torque and flux ripple and unsteady switching frequency.In this paper,the direct torque control of permanent magnet synchronous motor(PMSM)is studied.The super-twisting sliding mode control theory is introduced into the direct torque control to reduce torque,flux ripple,improve speed dynamic response speed,suppress speed overshoot,obtain high-precision rotor position and speed information for PMSM DTC carries on the research of theory and simulation experiment.The main contents of this paper are as follows:Based on the coordinate coefficient mathematical model of PMSM,the basic principle of PMSM direct torque control technology and the structure of control system are introduced.The simulation model is built in MATLAB / Simulink software,and the simulation results are analyzed.The SVM-DTC system,which is worth to reference voltage vector,is theoretically expounded by using the magnetic chain and torque error.The super-twisting sliding mode controller is used to replace the PI controller on the speed loop,the magnetic chain ring and the torque ring to improve the control performance of the system and to prove the stability of the system after introducing the Super-twisting sliding mode controller.The sensorless control of Permanent magnet synchronous motor(SVM-DTC)system using magnetic chain and torque error is worth to the reference voltage vector.This paper introduces the principle of thetraditional sliding mode observer and analyzes the stability of the traditional sliding mode in the system.In view of the poor chattering and rotational speed of the traditional sliding mode observer and the accuracy of the rotor position estimation,the traditional sliding mode observer is replaced with the super-twisting sliding mode observer to restrain the chattering phenomenon caused by the traditional sliding mode observer and to solve the problem of the poor accuracy of the rotor position and speed estimation.Based on the experience of reducing torque ripple by direct torque control,a permanent magnet synchronous motor with a SVM-DTC link is combined with super-twisting sliding mode control theory,The theoretical proof of the system stability after introducing the super-twisting sliding mode control theory to the flux-free chain loop SVM-DTC of permanent magnet synchronous motor is proved,and the experimental platform is used to verify the experiment.