The integrated interleaved Boost-LLC resonant converter ZVS enables conditional analysis

Purpose Aiming at the core issue of traditional LLC resonant converters losing zero-voltage switching (ZVS) conditions under wide input voltage range, leading to drastic efficiency degradation, this paper aims to propose an integrated interleaved Boost-LLC resonant converter topology. Through codesign of Boost inductors and the resonant network, a quantitative analysis model for ZVS achievement is established. Design/methodology/approach First, the topology of the proposed converter is analyzed. Then, the theoretical and practical ZVS realization conditions are thoroughly examined, with the ZVS critical current equation derived based on the switching-node charge balance principle. The proposed topology adopts switch-device multiplexing technology to integrate two-phase interleaved Boost inductors into the full-bridge LLC arms, achieving deep coupling between front-stage voltage boosting and rear-stage resonance through fixed-frequency Pulse Width Modulation control. A prototype of the integrated interleaved Boost-LLC resonant converter was developed. Findings Experimental results demonstrate that across an input voltage range of 120–240 V and load variation from 10% to 100%, the drain-source voltages of all switches return to zero before gate signals arrive, achieving 100% ZVS realization rate. The experimental results validate the feasibility of the proposed converter. Originality/value The switch tube can achieve zero-voltage turn-on (ZVS) within a wide load range and the entire input voltage range, significantly reducing the turn-on loss and thereby enhancing the overall efficiency of the converter. This converter is applicable to the fields of new energy such as photovoltaics and fuel cells, and can meet the requirements of wide input voltage range and small current ripple.