Modelling and Simulation of Direct Torque Controlled Induction Motor Drive using Slip Speed Control

Abstract

In this paper an effective control strategy to reduce the torque and flux ripple in direct torque control (DTC) of induction motor drive based on a slip speed control of stator flux is presented. This control strategy is applied to three-level inverter configuration using cascaded two two-level inverters for improving the performance of the system. Torque control is achieved by reference stator flux angle which is generated from the sum of incremental change in stator flux angle and actual stator flux angle. Modelling and simulation of proposed DTC is presented and results of the simulation are compared with basic DTC. From the simulation results it is observed that the torque and flux ripple are less with proposed DTC and also an improvement in the steady-state performance of the drive system at high and low speed operation.