High-efficiency voltage sag protector with low ground leakage current

Abstract

This paper proposes a high-efficiency voltage sag protector with low ground leakage current. The line-frequency transformer of the conventional system is replaced by a bidirectional dc-dc converter. A bidirectional dc-ac inverter copes with voltage sag and interruption. It has low ground leakage currents by the common grounded capacitors. A bidirectional dc-dc converter transfers the electrical power between the battery and the bidirectional dc-ac inverter. The proposed system improves the power efficiency and power density compared to the conventional system. Experimental results for a 1.0 kW prototype system are presented to evaluate the performance of the proposed system.