Single-Phase Isolated AC-AC Symmetrical Full-Bridge Converter

This work proposes an ac-ac converter based on interleaved transformers associated with the dual active bridge (DAB) converter. The resulting symmetrical full-bridge converter (SFBC) can achieve high efficiency over a wide range of the output power and bidirectional power flow, as well as high power density owing to the possible integration of magnetics. The voltage waveforms on the high-frequency transformer (HFT) present five levels, resulting in filter elements with reduced dimensions. A detailed mathematical analysis of the SFBC comprising the operating stages, modulation technique, and soft-switching range is derived. An experimental prototype rated at 1 kW is implemented to validate the theoretical assumptions, thus demonstrating that the SFBC is capable of providing input power factor correction (PFC) and a load voltage waveform with low harmonic content.