Reconfigurable Bidirectional Interleaved Quasi-Resonant Flying Capacitor DC/DC Converter for High and Wide Voltage Range Applications

초록

This paper proposes a reconfigurable bidirectional interleaved quasi-resonant flying capacitor dc/dc converter optimized for high step-up and wide voltage range applications. Conventional converters employ two-level Vcd and typically operate as a half-wave resonant boost converter in forward direction and a half-wave resonant buck converter in backward direction. In contrast, the proposed topology utilizes three-level Vcd in both directions, which can expand the gain range from 2-∞ to 1-∞ in forward direction and from 0-0.5 to 0-1 in backward direction. This enhanced gain profile enables the use of transformers with lower turn ratios, thereby reducing parasitic inductance and capacitance, which in turn mitigates voltage spikes and electromagnetic interference (EMI). The interleaved configuration of the high-voltage-side flying capacitor cells enables capacitor voltage balancing with three-level Vcd. The feasibility of efficient power conversion can be achieved using a low turn-ratio transformer under high conversion ratio. © 2025 Korean Institute of Electrical Engineers Electrical Machinery and Energy Conversion Systems Society.

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