Direct Torque Control with 5-level cascaded H-bridge multilevel inverter for induction machines

This paper presents a Direct Torque Control (DTC) utilizing a 5-level cascaded H-bridge multilevel inverter (CHMI) for induction machines. A multilevel hysteresis controller for flux and torque, with 12-sector stator flux angle detection and a precise look-up table for optimum vector selection is proposed to enhance DTC performances. A theoretical concept of the proposed DTC system in terms of flux and torque control and estimations and optimal voltage vector selection are studied in this work. The simulation results obtained from MATLAB/Simulink software showed that the proposed system significantly improved the DTC drive in terms of dynamic performance, smaller torque and flux ripple and lower THD.