Control Strategy and Modulation Scheme of Three-Phase Quasi-Single-Stage Isolated AC–DC Converter Based on Dual Active Bridge

This article proposes a three-phase quasi-single-stage isolated AC-DC converter, comprising a hybrid active third-harmonic injection buck-type rectifier (H3R) and a dual active bridge (DAB). Based on the input current analysis, globally optimal working modes of the DAB converter are derived through optimal triple-phase-shift (TPS) modulation, minimizing conduction losses while achieving wide-range zero-voltage switching (ZVS). A voltage-current closed-loop control strategy is proposed to regulat