A Bridge-Arm Multiplexing FSBB-CLLLC Converter with a Wide Voltage Regulation Range

This paper cascades the FSBB converter with the CLLLC converter to form the FSBB-CLLLC converter, which is applicable to application scenarios requiring bidirectional wide DC gain range. By adjusting the duty cycle of the FSBB - stage converter, a wider gain range can be obtained. Meanwhile, the CLLLC converter is made to operate in the DCX mode to ensure that the system has a relatively high transmission efficiency. Additionally, this converter adopts the bridge arm multiplexing method, which reduces the number of MOS tubes and also cuts down the losses. This paper conducts research on the different working modes that may be caused by different phase angles when the FSBB-CLLLC converter operates in the forward and reverse directions. At the same time, the ZVS boundary conditions of this converter are analyzed and studied. And the FSBB inductor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$L$</tex> is optimized in combination with the ZVS boundary conditions within the full-load and full-gain range. Furthermore, the bridge arm multiplexing structure enables the switching tubes of the FSBB stage to achieve ZVS with the help of the resonant current of the CLLLC stage, which is beneficial to the improvement of the overall efficiency. Finally, a 500W prototype is built in this paper to verify the theoretical analysis and the proposed scheme.