A Novel Adaptive Modulation Scheme for Reactive Power Minimization in Dual Active Bridge with Varying Load Demands

In electric vehicle (EV) charging stations, bidirectional DC-DC converters act as an interface for power transfer between the charger and the EV. This study utilizes a parallel arrangement of dual active full bridge (DAFB) converters to manage substantial and fluctuating power needs, with each DAB module contributing proportionately to the overall power supplied to the load while maintaining galvanic isolation and good efficiency. Despite its benefits, individual DAB converters suffer efficiency decline under variable load situations due to increased reactive power. A reactive power minimization method utilizing triple phase shift (TPS) modulation is implemented for each DAB unit within the parallel architecture to address this issue. This approach dynamically optimizes the phase shift angles based on real-time power demands, thereby improving overall system efficiency and broadening the soft-switching range. The suggested method is evaluated using comprehensive simulations, which exhibit a significant decrease in reactive power and enhanced performance across a broad working range, confirming its appropriateness for EV charging applications.