Improved Direct Torque Control of Induction Motor Using Fuzzy Logic Based Duty Ratio Controller
Classical DTC has inherent disadvantages such as: problems during starting resulting from the null states, the compulsory requirement of torque and flux estimators, and torque ripple. In this paper the improved response of the DTC is achieved by varying the duty ratio of the selected voltage vector during each switching period according to the magnitude of the torque error and position of the stator flux using Fuzzy logic. A duty ratio control scheme for an inverter-fed induction machine using DTC method is presented in this paper. Fuzzy logic control is used to implement the duty ratio controller. The effectiveness of the duty ratio method was verified by simulation using Matlab SIMULINK.