Three-phase dual active bridge DC-DC converter: Comparison between YY and AY transformer connections

This paper presents a comparison of different transformers connections of a three-phase dual active bridge DC-DC converter. The connections that are evaluated are star-star and delta-star. The main objective of this comparison is to evaluate the stress of the semiconductors based on the RMS current and the current values at the switching instants; as well as the RMS current and the rated power of the high-frequency transformers. From this analysis, it is concluded that a lower stress can be obtained in both the transformer and semiconductors using the transformer connected in delta-star for a wide range of output power.