Research On Sensorless Direct Torque Control Of Permanent Magnet Synchronous Motor Based On Sliding Mode Control

As a high-performance control strategy,Permanent Magnet Synchronous Motor Direct Torque Control(DTC)is widely used due to its simple control structure and fast torque response.Conventional permanent magnet synchronous motor direct torque control usually adopts hysteresis control structure and is realized by PI control.In view of the outstanding problems of inverter switching frequency,large parameter overshoot and poor anti-disturbance,this paper studies the high-performance control scheme of permanent magnet synchronous motor direct torque control system from two aspects of control strategy and sensorless operation.The specific content is as follows:In this paper,the coordinate system is selected reasonably,and the direct torque control model of permanent magnet synchronous motor based on PI and hysteresis control is established,and its effectiveness is verified.After that,the permanent torque synchronous motor direct torque control model based on Space Vector Pulse Width Modulation(SVPWM)is established to reduce the inverter switching frequency and optimize the reference voltage vector instead of hysteresis controller.Then,in order to continue to improve the dynamic characteristics and robustness of the permanent magnet synchronous motor direct torque control system,in terms of controller improvement,the second-order terminal sliding mode control is applied to the rotational speed of the traditional permanent magnet synchronous motor direct torque control system.The speed controller based on the new approaching law is applied to the direct torque control model of permanent magnet synchronous motor based on SVPWM,and the fuzzy adaptive algorithm is introduced to realize the adaptive adjustment of the parameters of the approaching law to solve the specific PI controller parameters of the motor.On the basis of the former,the Super-twisting sliding mode controller is designed and applied to the torque angular difference link,and the two form a hybrid sliding mode controller.Finally,in the sensorless operation,the sliding mode observer based on the arctangent function is designed to set the phase compensation reasonably.The controller simulation experiment shows that the new approaching sliding mode speed controller can decrease the relative error of the speed under load to 0.16%,and the hybrid sliding mode controller can decrease the error of the speed without load to 0.06%.Compared with the PI control and the common exponential approaching law,the improved control algorithm has significant and optimal performance in terms of static performance,dynamic performance and robustness without load,under load and speed disturbance.Observer simulation experiments show that the sliding mode observer based on the arctangent function reduces the phase compared with the model reference adaptive observer in the 37 th reference in the case of without load,speed and torque increase.The delay increases the accuracy of the rotor position estimate.