Centralized Regulation Scheme for a Parallel-Mode Switched-Capacitor Converter System With Simple Unit Commitment

Novel load regulation methods for switched-capacitor converter (SCC) system operating in parallel mode are proposed. SCCs are ready for integrated design which is ideal for mass production and also enables power conversion in compact footprint. At the same time, they are excellent candidates for parallel mode operation since the load current sharing among them is automatically allocated by the inherent droop characteristic, which is determined by the equivalent internal resistance. Instead of controlling the individual switching frequency of SCC units, this paper proposes a number of unit commitment schemes which regulate the output voltage by adjusting the number of activated SCC units. In addition to conventional discrete unit commitment, intermediate number of activated units is realized by employing pulse-dropping pulse width modulation. The proposed methods are verified by simulation and the experiment of a parallel SCC system consists of a number of double-mode zero-current switching SCC units.