Direct Switching Current Control for Series Resonant Dual Active Bridge DC–AC Converters Based on Time-Domain Analysis

Optimal control of series resonant dual active bridge (SRDAB) converters has attracted significant attention in recent years. Existing control methodologies primarily rely on either offline optimization or online calculations based on simplified models, which inherently involve a trade-off between computational burden and control accuracy. To address this challenge, this article proposes a novel direct switching current control strategy for SRDAB DC–AC converters based on accurate time-domain analysis (TDA). Unlike conventional methods that primarily focus on power regulation and have difficulty in accurately modeling instantaneous switching currents, the proposed strategy directly regulates the commutation current predicted by the TDA model, thereby enabling reliable ZVS over a wide operating range. By establishing a high-fidelity time-domain model, the state trajectory of the resonant current and voltage is analyzed, and the analytical relationships between switching currents and control variables are derived. Building on this analysis, an online direct switching current control strategy is designed to precisely regulate critical turn-on currents. Dedicated zero voltage switching (ZVS) and backflow power minimization schemes are proposed to optimize soft-switching performance and reduce switching losses. Finally, a 500 W hardware prototype is developed and the experimental results validate the effectiveness and feasibility of the proposed strategy.