Minimization of Current Stress for Dual Active Bridge Converters Based on Model Predictive Control with Enhanced ZVS Ability

Efficiency is a crucial concern for dual active bridge (DAB) converters. Although many studies on novel modulation schemes have attempted to improve the efficiency, achieving the optimal balance between current stress and zero-voltage-switching (ZVS) ability remains challenging. In addition, due to the wide operating range of DABs, small-signal models have to be setup at each equilibrium point to purpose a high performance of liner controllers. Existing works mainly employ the slow-loop to prevent oscillations during transitions, which degrades the dynamic and bandwidth. To address the current state of research, this article proposes a triple-phase-shift modulation combined with model predictive control (MPC) for DABs. Herein, a designed cost function initially calculates shift-angles. Subsequently, a proposed optimization segment for ZVS checks and revises the ZVS ability to select an optimal set of shift angles. The current stress is minimized on the premise that the wide range of ZVS is guaranteed. Meanwhile, the dynamic performance is improved through the nonlinearity of MPC. Finally, a 1.4-kW scaled-down prototype is built, and the experimental comparisons with other schemes verify the effectiveness and superiority of the proposed method.