FLC based hysteresis band adaptation to optimize torque and stator flux ripples of a DTC based IM drive

This paper presents a fuzzy logic controller (FLC) based direct torque control of induction motor (IM) drive to reduce the ripple in developed torque and stator flux. First the effect of amplitude of torque hysteresis band on the torque ripple of an IM motor is discussed. Finally, a strategy to reduce the ripple in the developed torque and stator flux is proposed by controlling the amplitude of the hysteresis bands. The FLC is used to determine the optimum amplitudes of torque and flux hysteresis bands based on the variations of motor speed and stator current. Further, in order to reduce the computational burden in this paper a bit by bit algorithm is used for calculation of flux sector position instead of the conventional trigonometric function. The proposed FLC Based DTC scheme for IM drive is simulated using Matlab/Simulink. The simulation results show better speed and torque responses of the proposed drive as compared to the conventional DTC scheme.