Space Vector Approach for Direct Torque Control Induction Motor drive

DTC is a vector control technique. With DTC stator flux and torque of induction motor can control separately. But during the estimation process some error occurs on the system which degrades the drive performance and also inverter switching frequency get varied. The error occur on the system is due to DC-link voltage. To improve the drive performance by reducing the error due to DC-link and to maintain switching frequency constant SVPWM technique is used here. Using this modulation technique space vector of stator voltage is controlled by providing proper switching sequence for inverter. SVPWM technique utilize the full DC bus voltage because of this harmonic contents are reduced. To maintain switching sequence constant the required DC link voltages for inverter are obtained through PI controller. PI controller reduces the ripple content on controlling parameter. In this paper DTC-IM drive performance are improved by reducing the estimation error with the help of DTC-SVM technique. The system implemented using MATLAB/SIMULINK model.