SAG mitigation of VSD using t-source inverter

AC Variable Speed Drives (VSD's) are very widely used in industrial, commercial and some residential applications. Voltage sag is regarded as one of the most important power quality disturbances due to its impact on sensitive loads. A voltage Sag is defined as a momentary decrease in the rms voltage, with a duration ranging from 0.5 cycles to 0.8 cycles. The loss of production and revenue occurs due to frequent tripping of equipments caused by voltage sag. This paper proposes a voltage sag mitigation technique using SWISS rectifier combined with T-source inverter. The T source inverter provides continuous input current and a higher boost voltage inversion capability. The SR is a PFC buck converter which provides controlled voltage at the DC-link. This rectified DC output voltage is fed to the TSI. The impedance network in this inverter is used to decreased or increased the input voltage depends on the boost factor. The proposed topology is simulated using MATLAB/Simulink and the simulation results are analyzed and is compared with the conventional methods.