A novel approach to minimize torque ripples in DTC induction motor drive

The direct torque control (DTC) speed control scheme of an induction motor surpasses the vector control in the sense that it controls the torque directly and does not use transformations and current modulator. The only snag in DTC scheme is the presence of high content of torque ripples in the output torque. This paper presents a novel approach towards the minimization of torque ripples by modifying the conventional three-level hysteresis torque controller used in DTC. A unique switching strategy has been developed to generate desired voltage vector. The comparison of the simulated results based on % ripple content shows that the proposed method has successfully reduced ripples in the torque under the various operating conditions.