Speed Control of an Induction Motor Using Ga Based Direct Torque Control

Abstract

Direct torque control (DTC) is a vector control strategy and it became very popular from previous two decades. The popularity is due to very fast dynamic torque response, simple structure, no coordination transformation required and absence of current and PWM controllers. In DTC, reference flux and speed are acts as inputs. Based on the errors between reference and estimated quantities and position of stator flux vector in two dimensional complex plane, voltage vectors are determined by the assisting of switching table. Variable speed control drives plays an crucial role in industrialization, so this paper concentrates on speed control technique of an induction motor using DTC strategy and also to improve the performance characteristics, speed controller gains are tuned by means of Genetic Algorithm (GA). GA gives best fit value and corresponding controller gains are selected to tune the controller which gives better performance characteristics. And also this paper describes, variation of controller parameters and steady state speed with respect to iterations. Induction motor is modeled in stationary reference frame and performance characteristics are observed by the help of SIMULINK/MATLAB.

Keywords: Induction motor (IM), Direct torque control (DTC), Genetic Algorithm (GA).