Analysis of Modulation and Optimal Design Methodology for Half-Bridge Matrix-Based Dual-Active-Bridge (MB-DAB) AC–DC Converter

Recent research reveals the merits of single-stage half-bridge matrix-based (MB) dual-active-bridge (DAB) converter for modular medium-voltage ac (MVAC) to low-voltage dc (LVDC) conversion. The complete set of modulation modes for this ac–dc converter is yet to be analyzed in the literature. Such holistic investigation is necessary before carrying out a design optimization of the ac–dc converter for given voltage and power specifications. The objective of this article is to present a comprehensive analysis of the half-bridge MB-DAB converter’s modulation possibilities and optimal design. The exhaustive sets of zero-current-switching (ZCS) and zero-voltage-switching (ZVS) constrained modulation modes for the half-bridge MB-DAB converter are systematically investigated and the analysis reveals the boundaries of operation and feasible modulation schemes. Suitable simulation results illustrating modulation limits of the ac–dc converter reinforce the theoretical analysis. Additionally, an efficiency (η)-power density (ρ) optimal converter design algorithm is presented, which reveals that an all-SiC half-bridge MB-DAB design with ZVS constrained modulation offers the bestη-ρdesign. The hardware prototype’s experimental results validate the converter’s operation.