Analysis and Comparative Evaluation of a Modularized Bridge Rectifier MVAC-LVDC Solid-State Transformer

Solid-state transformers (SSTs) are considered for interfacing a medium-voltage (MV) ac grid to a low-voltage (LV) dc load in applications like high-power EV charging. This paper provides the first detailed analysis of a new modularized bridge rectifier (mBR) SST, which essentially consists of a three-phase diode rectifier with isolated dc-dc converters connected in parallel to the diodes, explains the operating principle, proposes a control method, and verifies the theoretical considerations with comprehensive circuit simulations. Finally, considering a 10kV ac mains input, an 800V dc output and a rated power of 1MW, a comparative evaluation of the mBR SST against a state-of-the-art modular integrated-active-filter rectifier (mIAFR) SST indicates lower utilization of the mBR’s dc-dc converters but practical advantages like the absence of direct series connections of transistors and the need for only a single type of power electronic building block (PEBB).