A sliding mode controller based optimum UPQC with minimum VA loading

The paper deals with an optimized unified power quality conditioner (UPQC), which aims at the integration of series active and shunt active power filters with minimum VA loading of the UPQC. The series active filter is a dynamic voltage restorer (DVR), which is operated in twofold functioning mode. During the unbalanced voltage sag, the DVR compensates the unbalance in the voltage sag. It also regulates the voltage at the load end with minimum VA loading of the overall UPQC by voltage injection at optimum angle. Sliding mode controller with constant frequency is employed to ensure the exact tracking of the reference voltage by DVR. Validity of the proposed scheme is proved through extensive simulation results.