Modeling and analysis of resonant switched-capacitor converters with free-wheeling ZCS

This paper introduces a unified modeling methodology to describe and explore the loss mechanism of resonant switched-capacitor converter (SCC) operating in a self-commutation zero current switching (ZCS) mode. The conventional equivalent resistance concept, which assumes a single conduction path of the resonant current, is generalized and extended to model the losses in cases where the resonant current is divided across several conduction loops. The new modeling concept is compatible to describe the losses resulting from resistive elements as well as P-N junction devices, offering a solution for the equivalent resistance. Verification of the concept has been carried out by simulations and experiments on 3-30 W unity, double gain and multiphase Fibonacci resonant SCC with free-wheeling ZCS. A very good agreement is obtained between the theoretical calculations, simulations, and experimental results, well demonstrating model capability to identify the loss contributors in each conduction path.