A Novel Current Sharing Method for Multi-phase LLC Converter

Abstract

Multi-phase LLC resonant converter is widely used for lithium-ion battery charger because of the zero voltage switching (ZVS) for the primary-side MOSFET and zero current switching (ZCS) for the second-side diode. A novel method is proposed to deal with the current sharing problem for multi-phase LLC resonant converter. In the method, the resonant inductor and capacitor in each module is paralleled respectively, and the current is shared automatically without additional component. The current sharing characteristic of traditional two-phase LLC resonant converter and the proposed one is analyzed. The simulation is established to prove the feasibility of the method. The result shows the current is unbalance in traditional multi-phase LLC resonant converter and excellent current sharing is achieved with the proposed method.