Double-Loop Control Strategy for Buck/Boost-CLLLC Two-Stage Bidirectional DC/DC Converter

This paper adopts Buck/Boost and CLLLC cascade topology. Buck/Boost-CLLLC two-stage bidirectional DC/DC converter topology and its control strategy are suitable for medium and high-power applications with large fluctuation range of input voltage and bidirectional flow of power and have the advantages of wide input voltage range and high efficiency. Aiming at Buck/Boost-CLLLC two-stage bidirectional DC/DC converter, the working principle of bidirectional Buck/Boost converter and bidirectional CLLLC resonant converter is analyzed. The small-signal model of bidirectional Buck/Boost converter and bidirectional CLLLC resonant converter is built. A dual-loop control strategy for two-stage DC/DC converter is proposed, and a dual-loop controller is designed. Finally, the simulation model is built to verify. The validity of double-loop control strategy of Buck/Boost-CLLLC two-stage bidirectional DC/DC converter in wide input voltage range is verified. And the bidirectional power flow of Buck/Boost-CLLLC two-stage bidirectional converter is verified.