An FSBB-CLLC Hybrid Isolated DC-DC Converter for Application in Energy Routers

Facing the challenge that isolated DC-DC converters in energy routers must simultaneously achieve wide voltage range, high efficiency, and electrical isolation, this paper proposes a hybrid architecture that cascades a Four-Switch Buck-Boost (FSBB) converter with a CLLC resonant converter. The FSBB stage serves as an active pre-regulator, handling wide-ranging input voltage fluctuations and providing a stable intermediate bus voltage for the subsequent CLLC stage. The CLLC stage operates at a quasi-constant frequency, focusing on achieving high-frequency isolation and soft-switching to pursue peak efficiency. Compared to traditional dual active bridge (DAB) solutions, the proposed structure demonstrates significant performance advantages in wide-voltage-range application scenarios, offering a highly promising solution for the power conversion core of next-generation energy routers.