An analytical method to evaluate flying capacitor multilevel converters and hybrid switched-capacitor converters for large voltage conversion ratios

Abstract

This work investigates the use of multilevel conversion in dc-dc applications that involve a large voltage conversion ratio. A quantitative method that can serve as a guide to compare and design multilevel topologies for large conversion ratio applications is presented. The proposed method keeps the conduction loss and switching loss the same across the different converters and employs the passive component volume as the single performance metric. As examples, flying capacitor multilevel converters (FCMC) and hybrid switched-capacitor (SC) converters are compared to conventional two-level buck converters, and are shown analytically to have significantly reduced passive component size. Three converter prototypes are implemented, based on the presented methodology to experimentally validate the method as well as demonstrate the advantages of multilevel converters.