Research On PMSM Direct Torque Control Based On Active Disturbance Rejection Controller

With the rapid development of the industry,the requirements for the speed regulation performance of the motor are getting higher and higher.Because of the simple structure and large torque inertia,permanent magnet synchronous motor plays an irreplaceable role in the field of speed control.The direct torque control strategy is the most commonly used strategy for speed control of permanent magnet synchronous motor.The traditional direct torque control strategy uses a Bang-bang controller as the torque and flux linkage control structure and a switch table for the switching process.While the Bang-Bang controller would lead to a large pulsation of torque and flux linkage,which would affect the stability of motors in the speed control process.In addition,because of the use of switch table,the switching frequency will not be constant.At present,the emergence of space vector modulation technology(SVM)has solved the problem of inconstant switching frequency.But,disappointingly,the problem of large pulsation and overspeed of torque and flux linkage remains unsolved.Therefore,the main contents of this paper are as follows:Based on SVM technology,this paper combines the theory of highorder sliding mode control(SMC)strategy with the direct torque control strategy of permanent magnet synchronous motor.Through an in-depth study of sliding mode control(SMC)theory,a suitable sliding mode surface is established.From this,the traditional direct torque controller is redesigned,and the stability of the newly designed sliding mode controller is verified.Through the above theoretical analysis,a direct torque control system of permanent magnet synchronous motor based on a high-order sliding mode controller is built.By the results of simulation experiments,the control performance of the controller is analyzed in detail.In order to further improve the control performance of direct torque controller,after analyzing the above-mentioned control performance,this paper combines Active Disturbance Rejection Control Theory(ADRC)with direct torque control(DTC)to form a new control scheme.Through an indepth study on the theory of active disturbance rejection control,a state equation applied to permanent magnet synchronous motor is established.By deeply analyzing three control parts of this theory,a nonlinear autodisturbance rejection controller with a speed loop and a flux linkage loop is set up to meet the nonlinear demand of the system and improve the control performance of the system.Using simulation software,a direct torque control system for permanent magnet synchronous motors based on ADRC is built.Through the simulation results,the control performance of the controller is compared and analyzed.(3)In order to verify the actual application status of the abovementioned control strategy,with the help of RT-LAB real-time simulator model OP5700,this paper builds a semi-physical simulation platform with the simulator as the core.The experimental results prove that the control strategy proposed in this paper is effective and feasible in actual projects.