The transition towards higher-voltage clean energy systems—spanning electric vehicles, energy storage, renewable generation, and DC distribution—has accelerated research in advanced medium-voltage direct current (1.5–100 kV) converter topologies. This paper presents a single-stage, high switching frequency, low input current ripple, isolated bidirectional current-fed dual active bridge DC-AC converter intended for high-step ratio applications leveraged, by a Modular Multilevel Converter (MMC) connected to a three-winding transformer. Switches in back-to-back configuration have been used in the AC side to guarantee a smooth change of polarity, enabling DC-AC conversion and maintaning zero-current switching at turn-off through the entire switching range of primary switches. While recent work have explored MMC-based DC-DC conversion, this paper focuses mainly on the DC-AC bidirectional power transfer. This paper includes the converter topology explanation, operating principles, modulation, modelling, and experimental validation.
