Optimal Control Path for DAB Based Solid-State Transformer

This article proposes a control strategy for single-stage Dual active bridge (DAB) based Solid-State Transformer (SST) converter. The proposed control strategy utilizes two control variables to develop a control path that increases soft switching range while minimizing the transformer current stress. The article analyzes zero voltage switching (ZVS) conditions and transformer current characteristics for single-stage DAB based SST converter. Analytical expressions are derived for implementing the control strategy, therefore no lookup tables are used. The performance of the proposed control strategy is compared with the conventional phase-shift (PS) control technique in terms of ZVS range and peak transformer current. Finally, the effectiveness of the proposed control strategy and the validity of the theoretical analysis are confirmed by experimental data.