Multi-Objective Efficiency-Oriented Optimization for DAB Converters Minimizing Current Stress and Backflow Power with Soft-Switching Assurance

Vehicle-to-Grid (V2G) electric vehicle chargers are becoming increasingly important due to their potential to enhance grid stability, support renewable energy integration, and provide economic benefits. This has led to a growing demand for dual active bridge (DAB) bidirectional DC-DC converters. While current stress and backflow power collectively impact DAB converter performance, existing optimization methods are mostly single-objective, focusing on just one of these two factors. In other words, there is rarely any co-optimization to minimize both current stress and backflow power simultaneously. To address this limitation, this work proposes a multi-objective, efficiency-oriented algorithm that minimizes current stress and backflow power simultaneously by optimizing triple phase shift (TPS) modulation parameters. This is achieved by combining time-domain analysis of the DAB under TPS modulation with an analytical power loss model into an automated, holistic digital optimization tool. Compared to conventional single-objective TPS methods that focus solely on current stress optimization, the proposed tool further improves power efficiency across certain power ranges. The validity of this multi-objective optimization method is verified through simulations and experiments.