Study Of PMSM Direct Torque Control Based On Super-Twisting Sliding Mode

The structure of permanent magnet synchronous motor(PMSM) is introduced in this thesis,and in surface mounted permanent magnet synchronous motor, as the control object, is analyzed in mathematical model in different coordinate systems. The simulation model of permanent magnet synchronous motor is established on the MATLAB/Simulink platform. The principle of direct torque control(DTC) is introduced in this thesis, and the realization of permanent magnet synchronous motor is described, which lay the theoretical foundation for the combination of in the later thesis.The principle of Space vector pulse width modulation(SVPWM) technology and its implementation are described in detail in this thesis, and then based on the direct torque control, combining SVPWM with direct torque control of PMSM, SVPWM-DTC system is formed and the simulation model of SVPWM-DTC system of permanent magnet synchronous motor in MATLAB/Simulink platform is established. The correctness of SVPWM- DTC system is verified by simulation experiment,and at the same time, it is found that the system robustness is poor.For the defects of SVPWM-DTC system of permanent magnet synchronous motor, a two order sliding mode control algorithm-- Super-Twisting sliding mode(STSM) control algorithm is proposed, and the STSM algorithm is introduced. The electromagnetic torque controller and stator flux linkage controller are designed. The two controllers are applied to the SVPWM-DTC system of permanent magnet synchronous motor, forming the STSM-DTC system and establishing the simulation model of STSM-DTC system of permanent magnet synchronous motor in MATLAB/Simulink platform. The correctness of STSM-DTC system is verified by simulation experiment, and at the same time,the results are compared with the SVPWM-DTC system simulation results and analyzed, proving the validity of the improved system.