Dynamic voltage restorer using PWM AC-AC Converter with switching cell structure

This paper presents dynamic voltage restorer (DVR) employing a direct pulse width modulation (PWM) AC-AC converter solving commutation problem. By using a single-phase PWM ac-ac converter that uses basic switching cell structure and coupled inductors, the proposed DVR does not need to sense the input voltage polarity for the safe commutation. Although input voltage is highly distorted, the proposed scheme ensures reliable operation of ac-ac converter. Using two additional bi-directional switches, the proposed DVR can compensate both voltage sag and swell of the input voltage. A 300 W prototype single-phase DVR is developed, and its performances are verified through experiment.