Analysis and Modeling of Transient Voltage Overshoot Behaviors in Bidirectional Phase-Shift Full-Bridge Converters

The growing advancements in renewable energy, EVs, and DC microgrids are driving the demand for high-density, high-efficiency bidirectional battery chargers. An essential component in these systems is an isolated DC–DC converter that interfaces with a battery operating across a variable voltage range. Phase-shift full-bridge (PSFB) converters have gained significant attention in battery charging applications due to their simple architecture, wide voltage range compatibility, and low current ripple. However, in bidirectional operation, PSFB converters exhibit a large inherent voltage overshoot on the transformer's secondary side, resulting in high voltage stress on the secondaryside switches. This article introduces a simplified circuit model for evaluating voltage overshoot, supported by a mathematical framework for quantifying and characterizing the phenomenon. Factors such as nonlinear capacitance, initial current, and the dead time are thoroughly analyzed for their impact on voltage overshoot. The proposed model offers a valuable tool for assessing voltage overshoot and guiding the development of suppression techniques, providing deeper insights into circuit behavior