A Capacitive Galvanically Isolated Full-Bridge Converter

Abstract

This article proposes a transformerless, capacitively isolated converter based on a full-bridge topology with phase shift control. Compared to the existing capacitively isolated converters, the proposed design offers the advantage of zero mean voltage across the isolating capacitors, thereby reducing voltage stress. A comprehensive analytical model is developed to describe the converter’s operation in both continuous and discontinuous conduction modes. The model is validated through an experimental prototype tested at power levels up to 6 kW and switching frequencies up to 500 kHz, achieving a peak conversion efficiency exceeding 98%. The experimental results confirm the accuracy of the theoretical model and waveforms.