A Three-phase Single-Stage Dual-Active-Bridge AC-DC Converter With Single-phase Operation Capability

In this paper, a new topology of a three-phase single-stage Dual-Active-Bridge(DAB) AC-DC converter with single-phase operation capability is proposed. In order to allow a three-phase AC-DC converter to operate in single-phase AC-DC mode, a large number of electrolytic capacitors are always connected in parallel to the DC bus to minimize the effect of second-order voltage harmonics. The proposed topology is able to significantly reduce the capacitance demand of the DC bus by adding capacitors at the center tap of the transformer's secondary side, which absorb the double-frequency ripple energy during single-phase operation. The correctness has been validated by simulation in PLECS.