Simplified Hybrid Dual-Bridge LLC Resonant Converter With Reduced Passive Components and Loss for Emergency Power Supply

The proportion of passive components loss in the total power loss of inductor–inductor–capacitor (LLC) resonant converters has reached a critical point. To address this issue, this article proposes a simplified hybrid dual-bridge LLC resonant converter to reduce passive component losses. It consists of a primary LLC resonant converter and an active clamp auxiliary bridge converter connected in parallel. The turn-off current of the LLC resonant converter over the entire range is greatly reduced by means of the clamping operation of the auxiliary converter. Compared with conventional dual-bridge LLC resonant converters, the proposed converter requires only one resonant tank, which can reduce the number of passive components; therefore, it can achieve a 26.5% resonance component cost reduction and a 13.8% total volume of inductor reduction. A 1.2-kW prototype of the hybrid dual full-bridge (FB) three-leg LLC resonant converters is built as a case study to validate the proposed approach. Compared to conventional dual FB three-leg LLC resonant converters, the proposed converter can achieve a 27% reduction in passive component losses without sacrificing soft switching performance.