In this paper, self-regulation of stator flux in Direct Torque Control (DTC) of Induction Motor Drive is achieved. Direct torque control is based on torque, flux hysteresis controllers and the stator flux angle. Based on hysteresis controllers and stator flux angle a look up table is constructed. In DTC Stator flux is divided as six sectors. Due to look up table uneven voltage vectors are distributed to control the stator flux and torque in a DTC induction machine. The stator flux magnitude droops at every switching sector transition, particularly when the machine is running at low speed with a heavy load. To overcome this sectors are slightly wavered for some angle. The performance of the controllers are investigated for load torque disturbance using Performance Indices ISE, ITAE and ITSE. The results clearly shows sector oscillation improves the performance to further reduce the torque ripple saw tooth sector wavering is used. © Research India Publications.
Sampath Kumar S. and Dr. Balamurugan S., “Sensor less Direct Torque Controlled Induction Motor Drive with Torque, Flux and Speed Ripple Minimization”, International Journal of Applied Engineering Research, vol. 10, no. 55, pp. 3547-3551, 2015.