Comparative Analysis Of Two-Level &; Three-Level Svpwm Based DTC IM Drives

In the present context, many control techniques are available for induction motor (IM) drives. However, among various techniques, direct torque control (DTC) of IM fed by a voltage source inverter (VSI) is recognized as one of the famous control technique used for high performance torque control in induction motors (IM). It is a simple scheme which can be built without any mechanical speed sensors. This scheme is based on the deviance of the estimated values of the motor torque and flux from the predefined standard values. The output of the two-level VSI is voltage vector which is fed to the IM for its control. However, a three-level inverter fulfils the requirement of more exact stator voltage to produce the preferred changes in flux and torque of the induction motor. Therefore, conventional DTC scheme is modified with a three-level Neutral point clamped inverter instead of two-level voltage source inverter. Finally, a comparative analysis of two level and three level inverters has been made in the paper.