Battery charging-discharging control method for PV system capacity reduction

Providing against a power failure due to disasters, the authors have developed a photovoltaic power generation system as a back-up system for the optical network unit. Because of the restricted space in which the system is to be installed, in this paper, the authors intend to reduce the capacity of the developed PV power system, especially the battery capacity. Considering the PV share and the commercial power supply share, they propose a novel control method of battery charging-discharging for the battery capacity reduction. According to the battery residual capacity, the control circuit manages the power flows in the system. First, they develop a precise computational simulator for the proposed system. Next, using the measured solar irradiance data, they investigate the system performances with the proposed control method by the simulator. Finally, some field trial results are also reported, which demonstrates the validity of the control method