Review of Transient Handling of DABs from an Operational Modes Perspective

Dual Active Bridge (DAB) converters have emerged as a critical technology in modern energy conversion systems, offering a means of seamless bi-directional power flow with Galvanic isolation with high efficiency, and high-power density. Common applications range from renewable energy systems to electric vehicle charging. However, transient performance, particularly DC-bias current during mode transitions, remains a significant challenge, impacting reliability and efficiency. While existing literature extensively covers steady-state optimization and topology advancements, a comprehensive analysis of transient mitigation strategies is notably absent. This paper bridges that gap by presenting a systematic review of transient mitigation techniques for DAB converters, focusing on phase-shift modulation strategies. We first analyze the root causes of inductor DC-bias current and then classify and evaluate state-of-the-art transient optimization methods, including the novel Unified Phase-Shift Control Strategy. By comparing these approaches, we provide actionable insights for selecting optimal strategies under diverse operational scenarios, advancing the design of robust, high-performance DAB converters for next-generation power systems.