Single-Phase Isolated AC-AC Converters Based on the Dual Active Bridge Converter

This article presents three single-phase isolated ac–ac converters based on the dual active bridge (DAB) converter and interleaved transformers. The structures allow obtaining filter elements with reduced dimensions, as well as bidirectional power flow and high efficiency over a wide load range. Multilevel voltage waveforms exist in the input and output sides of the symmetrical converters, resulting in reduced harmonic content. The possible arrangements include a symmetrical half-bridge converter (SHBC), a symmetrical full-bridge converter (SFBC), and a symmetrical interleaved full-bridge converter (SIFBC). The introduced topologies can be regarded as prominent solutions for applications involving solid-state transformers, dynamic voltage restorers, and uninterruptible power supplies. A thorough mathematical analysis of the SHBC is carried out and experimental results are presented to investigate the converter performance in steady-state and transient conditions.