A Switching Algorithm for AC-AC Converter Based Voltage Compensator without Using Snubber Circuit

Series voltage compensation is used in low-voltage distribution system to compensate for voltage variations. The compensators are indeed series-connected converters which inject the missing voltage in series to the grid in case of voltage sag. In this paper, a switching algorithm for AC-AC converter based voltage compensator is proposed. As the bidirectional AC power electronic switches are used in the AC-AC converters, considering the switching dead-time, snubber circuits should be used in parallel with the switches to provide a current path during the dead-time and hence to reduce the dv/dt stresses on the switches. The snubber circuits increase the circuit elements and have their own power losses. Using the proposed switching algorithm, the snubber circuits could be eliminated since a current path is always (including the dead-time) guaranteed. In order to evaluate the proposed algorithm, the simulation studies and discussions are presented.