Hybrid Switched Capacitor DC-DC Converter Based On MMC

Abstract

Different types of dc-dc converters have been subject of research to fulfill the need of interconnecting renewable generation sources, existing or new grids, electronic loads and battery based systems. To deal with high voltage levels and high power, Modular Multilevel Converter based structures have been proposed. On the other hand, for lower power ratings, Switched Capacitor and Hybrid Switched Capacitor converters have emerged due to their simple structures and self voltage balancing characteristics. In this scenario, a non-isolated Hybrid Switched Capacitor dc-dc converter based on Modular Multilevel Converter is proposed and its unidirectional structure is examined through circuit analysis. In the proposed converter, the voltage static gain is independent of the number of submodules, allowing a good regulation range of the output voltage for high voltage applications. Moreover, the Switched Capacitor behavior provides automatic clamp of the arms voltages, avoiding the need of ac loops to perform the arms voltage balance. A converter design methodology based on current spikes limitation is also proposed. All the theoretical analysis and the design methodology are validated through comparisons with simulated waveforms.