Comparative Analys is of Direct Torque Control in Three Phase and Five Phase Induction Motor Drives

Abstract

The Direct Torque Control(DTC)is a type of vector control technique which is used to regulate the torque and hence speed of an induction motor drive.This method is very efficient,cheap and is very easy to execute.The absence of mechanical speed estimators along with the ease of processing and computations make it the most preferred option among all vector control techniques.In this method, only the voltage and current are sensed and they are used to estimate the torque,flux and the angle between the rotor and stator flux.Depending on the torque and flux errors,a suitable voltage vector is selected to keep the errors within the desired tolerance region.At present times,three phase induction motors have become the backbone of industries.Lifts,agricultural pumps,conveyor belts,lathes, cranes,drilling machine,etc.are some of the prominent areas where induction motors have been very effective. These motors can be controlled using the scalar V/F control techniques.However,for applications requiring quick response vector control techniques like DTC are preferred. But the problem lies in the presence of torque ripples in case of DTC of three phase induction motor drive.Recently it has been seen that multiphase induction machines have the inherent feature of low torque pulsations.Hence they have replaced their three phase counterparts in areas like ship propulsions and aerospace industries where higher accuracy is required.This feature along with many other advantages of multiphase induction machines make them a strong competitor to their three phase counterparts in the field of industrial drives.This project aims to study and simulate the conventional DTC technique in a five phase induction machine with the help of MATLAB & Simulink and compare the results with its three phase counterpart to verify the effectiveness of the multiphase machine.