The modular bridge rectifier (mBR) topology represents an emerging single-stage SST implementation, featuring just one diode and isolated DC/DC converter per submodule to achieve superior power density and modularity. This paper presents the first comprehensive exploration of mBR’s multi-port functionality for MVAC / MVDC / LVDC power conversion. The quantitative analysis of each port’s achievable power range, accounting for topological constraints and current stress limitations, is presented.A novel branch current distribution method is proposed to reduce operational voltage range of branch DC/DC converters while compensating for MVDC current disturbances. Furthermore, the islanded operation without MVAC grid is discussed, wherein the three-port mBR morphs into three parallel input-series output-parallel (ISOP) DC/DC converters. A hierarchical control architecture capable of seamless transition between grid-connected and islanded modes is also introduced. Finally, all proposed operational modes of multi-port mBR SST are validated through a thorough simulation of a 250 kW demonstration converter connecting a 3.3 kV MVAC and a 4.67 kV MVDC grids to an 800 V LVDC load.
