Modified Direct Torque Control Scheme for Induction Machine Using Space Vector Modulation

Abstract

AbstractSince the introduction of vector control and direct torque control (DTC), independent torque and flux control are used for fast and accurate control of induction machine. Out of these two, direct torque control provides a faster response with simple control scheme. But DTC produces high torque and flux ripple and operates at variable switching frequency. Space vector modulation (SVM) can be used to overcome disadvantages of conventional DTC. Different direct torque control strategies using space vector modulation were introduced over the years. These control strategies involve coordinate transformation or feed forward decoupling or deadbeat in the controller. A direct torque control scheme for induction machine using space vector modulation without any coordinate transformation or feed forward decoupling or deadbeat is presented in this paper. Estimation of rotor speed using model reference adaptive system (MRAS) is also discussed. Performance of the presented control strategy is tested in MATLAB/SIMULINK. Simulation results are compared with conventional DTC results. Rotor speed estimation using MRAS also simulated, estimated speed is compared with measured speed. KeywordsDirect torque controlSpace vector modulationSensor less driveInduction motor drive