A PV generation system based on centralized-distributed structure and cascaded power balancing mechanism for DC microgrids

In this paper, a photovoltaic (PV) generation system based on cascaded power balancing mechanism has been proposed to enhance the renewable energy integration into DC microgrids. This generation system consists of a centralized DC-DC converter to interface the DC bus and a cascaded power balancing circuit to maximize the output power of series-connected PV modules. The cascaded power balancing circuit is implemented based on the resonant switched-capacitor topology. Maximum power point tracking (MPPT) algorithm have been developed for the cascaded power balancing circuit. A dual-phase-shift controlled full-bridge converter (DPS-FBC) is employed as the centralized DC-DC converter, which features high conversion efficiency and wide input voltage range for fluctuating PV generation. A dual-mode control strategy control strategy is developed for this DC-DC converter. Simulation and experiment results have verified the feasibility and effectiveness of the proposed PV generation system.