A AC-AC converter based topology for mitigation of voltage sag with phase jump

Abstract

Voltage sag remains to be a serious and most common power quality problem. A definitive solution towards compensation of voltage sag with phase jump is provided by Dynamic Voltage Restorer (DVR). The conventional DVR topologies however have dc-link and two stage power conversion, which increases its size, cost and associated losses. Therefore topologies without the dc-link mitigating sag by utilizing direct ac-ac converters, are preferable over the conventional ones. As no storage device is employed, compensation by these topologies is limited only by the voltages at the point of common coupling that is feeding the converters. A direct ac-ac converter based topology fed with line voltages is proposed in this work, for the compensation of sags with phase angle jump. The capability of the topology is compared with the other existing topologies and found to have increased range of compensation. Detailed simulations have been carried out in MATLAB and the results are presented.