Comparison of Conventional and Modified Direct Torque Control of Three-Phase Induction Motor Using Three-Level Flying Capacitor Inverter

Abstract

The work presented in this paper aims to compare the effectiveness of different control strategies to improve the performance of the three-phase Induction Motor (IM). The Conventional Direct Torque Control (CDTC) was employed as the first strategy for driving the IM. This control strategy causes high ripples in the IM's torque and speed due to the hysteresis comparators and a variable switching frequency due to the look-up table. A modified DTC strategy based on Space Vector Modulation (DTC-SVM) was chosen as a second strategy to enhance the performance of the IM using the two-level inverter. This method, which leads to the reduction of the torque and speed ripples and achieves constant switching frequency. As the multi-level inverter becomes most popular than the two-level inverter, the third strategy is devoted to adopting the three-level flying capacitor inverter (TLFCMLI) -based DTC-SVM. The third strategy uses the method of mapping the multi-level space vector based on basic two-level SVM. Matlab/Simulink software package is utilized to implement the suggested controllers. Simulation results show that the DTC-SVM based on TLFCMLI significantly enhances the IM's performance compared with the other two strategies from the voltage and current profiles, torque, and speed points of view.