Virtual-Synchronizer-Based Current Sharing Scheme in <i>m</i>-Phase Resonant DC-DC Converters System

The m-phase LLC resonant converter serves as an effective solution for reducing current stress and enabling highpower DC-DC conversion applications. However, variations in component parameters within the resonant tanks can lead to discrepancies in voltage gain, causing imbalanced output currents and thereby compromising the safe and reliable operation of the system. This paper delves into the underlying mechanism of current imbalance and elucidates the dynamic process through state-plane trajectory analysis. Consequently, a virtual-synchronizer based online current sharing scheme is proposed for m-phase resonant converters, which facilitates rapid online current balancing and ensures excellent synchronization performance. Moreover, it eliminates the need to designate a master phase, thereby enhancing the control flexibility, and the addition or removal of any phase does not disrupt the control process. The proposed method achieves synchronization and current sharing by constructing a virtual phase, without requiring additional hardware such as circuits and sensors. Results validate the effectiveness of the proposed method.