Modular realization of capacitive converters based on general transposed series-parallel and derived topologies

The realization of capacitive converters based on a modular approach is presented and analyzed in this paper. The converters are based on topologies with identical capacitors. First, the switching network (SN) of a basic series-parallel topology is presented. The analysis reveals the assembly and growth rules for expanding the topology to any number of capacitors. Subsequently, the SN for the more versatile and complex general transposed series-parallel (GTSP) topology is presented. The topology is expanded by defining a basic cell comprising a capacitor and five peripheral switches. The expansion of this converter improves its performance by ameliorating accuracy and regulation in the dc/dc voltage ratio. The control schemes of these converters are also presented with emphasis on the GTSP topology, whose switches are not assigned in advance. The control scheme for achieving the desired voltage ratio is described. A five-capacitor converter with its control is built to illustrate the theory in open-loop mode, which provides experimental results that are in full agreement with the analytical predictions.