New DTC control scheme for the induction motor fed with a three-level inverter

Abstract

In this paper a new scheme based on direct torque control strategy is presented. The new controller is used to control an induction motor fed with a three-level inverter. The new control scheme avoids the use of the classical hysteresis block and the look-up table. Instead, the torque and stator flux errors are used together with the motor speed to generate a reference voltage that can be synthesized using different techniques afterwards. Experimental results show some improvement regarding the reduction of torque ripple, stationary mean torque error, THD in stator currents and switching frequency when compared to the classical DTC scheme.