A 12-Sector Space Vector Switching Scheme for Performance Improvement of Matrix-Converter-Based DTC of IM Drive

This paper presents a direct torque control (DTC) switching scheme based on the direct matrix converter (DMC) using a 12-side polygonal space vector for variable speed control of an induction motor (IM). The conventional DTC scheme-based matrix converter (MC) is limited by 60° sectors of both flux and voltage vectors, which introduce a high torque ripple. The proposed method utilizes twelve 30° sectors of both flux and voltage vectors to increase the degrees of freedom for selection of proper vectors and reduce the torque ripple. The proposed switching scheme for the MC-based DTC of an IM drive select the appropriate switching vectors for control of torque with small variations of the stator flux within the hysteresis band. This improves the degrees of freedom in selecting the vector algorithm and the torque ripple as well. Furthermore, during the large torque demand, the probabilities of transgressing reference vector limits, which are enclosed by 12-side polygonal space vector, are reduced. Extensive simulation and experimental results are presented to verify the effectiveness of the 12-sector space vector switching scheme for the DTC of an IM fed by the DMC.