Power quality problems compensation with universal power quality conditioning system

The aim of this paper is to present a universal power quality conditioning system (UPQS) named after unified power quality conditioner, which is extended by adding a shunt active filter at the load side. Its main purpose is to compensate for both supply voltage and load current imperfections, such as: sags, swells, interruptions, imbalance, flicker, harmonics, reactive currents and current unbalance. Such system has better harmonic compensation characteristic, since there are no problems associated with passive filter operation. Converter and control analysis is presented, together with results showing the UPQS modes of operation. Index Terms--Active filter, converter, harmonics, power conditioning, power quality.