Backstepping DTC control of PMSM with robust adaptive law

Abstract

Abstract The traditional direct torque control (DTC) of permanent magnet synchronous motor (PMSM) is characterized by the feature of inconstant switching frequency and large ripples of flux and torque which is due to the hysteresis controllers adopted in the system. Besides, the modification of motor parameters, especially the rise of stator temperature, and load torque disturbance further leads to the speed steady-state error and fluctuation. A novel DTC method of interior PMSM based on the adaptive backstepping control with load torque and stator resistance identification is proposed in this paper. In order to reduce the ripples of the traditional DTC, a speed backstepping controller is designed to replace PI speed controller, and torque and flux backstepping controllers are designed to replace torque and flux hysteresis controllers in this algorithm. Owing to the real-time and accurate estimation of the stator resistance and load torque, the control variables can be instantly and simultaneously modify to ensure the accurate and fast response of the speed. The effectiveness and correctness of the presented method are verified through multiple simulation experiments, and the results indicate that the dynamic and static performance of the PMSM can be significantly improved by using the method.