Space Vectors Discretization-based Direct Torque Control Scheme for High Performance Induction Motor Drives

In this paper, a direct torque controller (DTC) based on discretization of space vectors (DSV-DTC) for induction motor drives is proposed. By using this technique, the number of voltage vectors is increased, consequently it reduces the torque ripple compared to the conventional DTC control scheme. Specifically, the switching table of the proposed DSV-DTC scheme is comprised of thirty-six nonzero voltage vectors compared to the six voltage vectors in the conventional DTC scheme. Furthermore, it makes use of a five – level torque hysteresis comparator instead of three-level of the conventional DTC. The performance of the proposed control scheme is validated by comparative simulation results obtained using MATLAB/Simulink platform. The comparative simulation results in both, steady state as well as transient operation exhibit a 79.63% reduction in ripple contents for torque, 93.32% for flux and 40.12% for stator current with the proposed DTC as compared to the convectional DTC.