Control Limits of Three-Phase AC Voltage Controller under Induction Motor Load

Thyristors are now widely used in many power electronics and motors drives applications. This is due to their several advantages such as relatively small size, low losses, market availability, and low cost. In this paper, a stator voltage control of three-phase induction motor by using thyristors is analyzed and simulated in details. The stator voltage has been controlled by phase angle control of three-phase supply. The effect of harmonic distortion in the line voltage and current have been studied and shown. The study reveals that, this method is suitable for applications requiring a low torque and low speeds. The power factor, efficiency and torque capability of the motor drop dramatically for lower voltages. Firing requirements and limits of control have also been studied. Recent PSIM6.1 program has been used to simulate the whole system. The simulation results from PSIM6.1 have been found in correlation with their counterpart from MATLAB 7.