A High Gain Switched Capacitor DC–DC Converter Suitable for Integration With Partially Isolated Multiport Converters

In this article, a high gain bidirectional switched capacitor dc–dc converter topology with common ground, is proposed for storage integration in dc microgrids. Unlike similar reported high gain topologies, the proposed topology provides a fixed rms ac voltage across two of its switch nodes, which allows it to be connected at an ac port of a partially isolated multiport converter. It also offers one third of the high side voltage stress across all the capacitors and power devices and automatic input current balancing function. Ability to handle wide source voltage variation and smooth low voltage side input current make this topology suitable for storage integration with lower inductor and switch current stress. Zero voltage switching during bidirectional modes of operation ensures low switching loss. These features of the proposed topology remain even when the converter is integrated at an ac port of partially isolated multiport converter. A 500-W laboratory prototype is developed to verify the wide input voltage (20–50 V) operation, while producing regulated dc output voltage of 220 V. The proposed converter achieves maximum efficiencies of 97.32% and 96.41% during its boost and buck modes of operation, respectively, which are among the highest reported in the literature.