A Soft-Switching High Step-Down Regulated DC-DC Converter: Topology Construction and Control Method

Resonant switched-capacitor converters have been widely studied and applied with the ability of high efficiency and power density, which well meets the requirements of data center power supply systems. However, due to its operation in DC transformer (DCX) mode, it does not have the ability to regulate voltage, which limits its application in certain situations and makes it difficult to meet the continuously increasing demand for data center applications. This article proposes a soft-switching high voltage step-down ratio hybrid switched-capacitor converter with voltage regulation capability and their corresponding phase-shift voltage regulation method. The voltage regulation principle and soft switching characteristics are analyzed in detail through mathematical derivation. In order to verify the theoretical analysis, an experimental prototype is built. The prototype can achieve 12 V output voltage under 40-60 V input voltage and the power density achieves 1987 W/in³ with 98.4% peak efficiency.