Paper Details

Induction motors are the starting point to design an electrical drive system which is widely used in manyindustrial applications. In modern control theory, different mathematical models describe induction motor according tothe employed control methods. The direct torque control (DTC) scheme being one of the most recent steps in thisdirection. This scheme provides excellent properties of regulation without rotational speed feedback. In this controlscheme the electromagnetic torque and stator flux magnitude are estimated with only stator voltages and currents andthis estimation does not depend on motor parameters except for the stator resistance. Literature review has been done tostudy the recent improvements in DTC scheme especially in low speed range operation to overcome the torque rippleproblem.The conventional direct torque controlled scheme suffers from great torque ripple due to fast response of torque inlow speed. The motor speed is an important parameter which effects on the motor torque ripple in low speed, whenapplying a forward nonzero voltage vector causes to jump up of motor torque and this leads to a positive ripple in torqueresponse. so we have to improve in look up table to reducing the torque ripple especially in low speed range. In thesisSimulation of conventional DTC scheme and Modified DTC scheme is described. In modified DTC scheme use the 12sector method and 5 level hysteresis band controller.

Aboti Ashish N, Patel Tejas I, Pritesh Mankad R, “Improved Direct Torque Control Strategies for Low Speed Range Operation of Induction Motor Drives”, International Journal of Advance Engineering and Research Development (IJAERD), Vol. 2, Issue 5, pp. 1150-1157, May 2015.