This paper presents a novel resonant converter architecture based on the parallel connection of two unfolded resonant converters. The design splits the 800 V bus into two 400 V segments on the AC side and utilizes a single current-doubler rectifier on the DC side. This configuration enables a high step-down voltage conversion ratio while minimizing switching and conduction losses. A galvanically isolated output transformer couples the two unfolded converters and facilitates phase-shift control of the output voltage, all while maintaining a constant switching frequency. The unfolded structure simplifies transformer design by relaxing insulation requirements and allowing for a turn ratio close to unity. Additionally, the circuit inherently provides short-circuit protection due to its voltage-controlled current-source behavior. The proposed architecture is validated through a 2.4 kW battery charger application, achieving an 800 V to 48 V step-down conversion.
