DTC-SVM of induction motor by applying two fuzzy logic controllers

Abstract

Among all control methods for induction motor drives (IMD), Direct Torque Control (DTC) seems to be particularly interesting being independent of machine rotor parameters. In spite of its simplicity, DTC allows good torque control in both steady and transient state. DTC drives utilizing hysteresis comparators suffer from high torque ripple and variable switching frequency. Major drawback of Classical DTC is high torque & flux ripples. The most common solution to this problem is to use Space Vector Modulation (SVM) depends on the reference torque and flux. In this Paper two-fuzzy controller along with the SVM technique is applied to inverter. The proposed two-fuzzy based DTC-SVM-IMD system, thereby dramatically reducing the torque ripple. Fuzzy-PI Controller to achieve precision speed control and Fuzzy Logic Duty Ratio Control is used to minimize torque & flux ripple. When Fuzzy Logic is used for the on-line tuning of the PI controller, it receives scaled values of the speed error and change of speed error. Its output is updating in the PI controller gains based on a set of rules to maintain excellent control performance even in the presence of parameter variation and drive non-linearity. These advantages allow implementing DTC-SVM-IMD with fuzzy for electric vehicles.