سعیده لطفی محمدآباد

This paper investigates the sophisticated analysis of a novel switching strategy for a matrix converter (MC) based direct torque control (DTC) of an induction motor (IM) drive. The proposed switching paradigm utilizes twelve 30° sectors for both flux and voltage vectors. Analytical expression of change rates of torque and flux for IM as a function of MC’s voltage vectors are derived. The influence of MC’s voltage vectors on the stator flux and electromagnetic torque variation is scrutinized and  an advanced switching scheme independent of any load and speed variation is developed. To decrease the switching losses of MC, the optimum switching state is selected by means of discretization and averaging on the flux variations. The performance of the proposed switching strategy is corroborated under rated conditions, and is also compared to the conventional hexagonal boundary switching scheme. The proposed method is characterized by low torque ripples, no need for rotational coordinate transformation and minimized switching frequency. The results verify that the degree of freedom to select proper voltage increases, and the torque ripple is hence significantly reduced up to 40%.