Analysis and design of a 1-kW 3X interleaved switched-capacitor DC-DC converter

Switched-Capacitor (SC) technologies have been an active research topic for DC-DC power conversion for many years. Without participation of inductor, they have the potential to achieve small size, light weight and high-power density. From literature research, most of the SC converters reported were implemented in low power level in the range of 5 to 50 watts. Typically they have discontinuous input current and use a large number of active switches. Recently, a new two-switch boost switched-capacitor (TBSC) converter was reported in [1] that achieves automatic interleaved DC-DC conversion with only two active switches. The TBSC converter can step up the input voltage by N times, where N=2, 3, 4, ..., with continuous input current and small output voltage ripple. This paper explores the feasibility of engaging this TBSC converter for high power applications in the kilowatts level with 3X gain. A simplified modeling method and analysis method is presented to provide solid guidance for analysis and design of the TBSC converter. A 1-kW 150/450-V prototype was implemented that achieved a peak efficiency of 97.5% at full load.