Reduced switch multiple active bridge DC-DC converter for modular solid-state transformers

This article introduces a reduced switch-multiple active bridge (RS-MAB) DC-DC converter as a building block of a three-stage modular solid-state transformer (SST), which decreases the number of switching devices and high-frequency transformers, thereby increasing power density and efficiency. Additionally, the extended triangular current mode (TCM) modulation is employed to enable soft switching across the entire operational range. A theoretical analysis of the general structure of the RS-MAB converter is presented. Numerical analysis, simulation, and laboratory-scale experimental results for a reduced switch-symmetrical quadruple active bridge (RS-SQAB) converter are provided to confirm the feasibility and validity of the proposed converter topology and its modulation method.