Fuzzy Direct Torque Control Of Permanent Magnet Synchronous Motor For High Speed Train

Permanent magnet synchronous motor(PMSM)has many advantages,such as high power factor,low energy consumption,simple structure and simple maintenance.Besides,PMSM has a completely closed structure,effectively shielding noise and reducing noise pollution.Because of its many advantages,PMSM has been widely used in the field of AC drive control in recent years and has become one of many research hotspots.Direct torque control(DTC)is widely studied because of its simple structure,strong robustness and rapid response ability,but the control mode has the defect of large torque ripple.It is necessary to obtain motor rotor accurately in direct torque control The rotor information is usually obtained by installing sensors.In order to solve this problem,sensorless control has become the research object of many experts and scholars.In this paper,the torque ripple and sensorless control in direct torque control are studied.Firstly,the research status of train transmission control system,direct torque control strategy and speed sensor-free technology introduced briefly.Then in the second chapter,the relationship between the coordinate systems is deduced,and the related mathematical model of PMSM is given.Then,the basic structure and principle of the traditional direct torque control system are briefly analyzed,and some causes of torque ripple are analyzed.In the third chapter,we focus on hysteresis control.In order to solve the problem of hysteresis control,a fuzzy controller based on flux and torque is used to replace the hysteresis controller.The simulation results and the related data show that the strategy is correct.In the traditional fuzzy controller,the fluctuation of the input signal may cause the fuzzy control rule not to be fully applied or insufficient,and finally make the expected control effect not available to the system.Aiming at the problem of fuzzy control rules,this paper studies and analyzes a variable domain fuzzy control strategy,which is adopted in this paper.The method of adding variable domain fuzzy control to torque loop is realized,and the control effect is improved.Aiming at the problems caused by sensor installation,the fourth chapter uses the model reference adaptive control system(MRAS)to detect the rotor information of the motor.a dual fuzzy control strategy is introduced in the PMSM DTC control system to further improve the system performance.the traditional PI controller in the MRAS system is replaced by the fuzzy PI controller,and the fuzzy PI control is used in the speed loop.Finally,the MATLAB/simulink simulation platform is used to simulate the control mode proposed in this paper under different working conditions,and the effectiveness of the system performance improvement is verified.