Hysteresis and fuzzy based nonlinear controllers for a direct torque control of an induction machine

In this work, a direct torque and flux fuzzy control (DTCF) scheme for voltage-source pulse width modulation inverter-fed induction motor drive is designed to replace the classical direct torque control (DTC) based on hysteresis-band comparators, because of the undesirable torque and current distortion caused by the basic DTC. A substantial reduction of these distortions can be obtained using the technique of DTCF at different sampling periods. In this way, a comparison study between these two techniques is carried out to demonstrate the effect of different sampling periods on the torque and current ripple. Simulation results validate the proposed method and support its ability to follow desired dynamics.