DC POWER SUPPLY SYSTEM

An objective is to provide a direct current (DC) power supply system capable of maximally generating electric power in a solar power generation process in consideration of an operation state of a load device serving as a power supply destination. In a rectifier (), a traffic volume acquisition unit () acquires an operation state (traffic volume) of a communication device (), and a power calculation unit () acquires power consumption of the communication device () corresponding to the traffic volume. Moreover, the power calculation unit () acquires output power from the rectifier (). A power comparison unit () acquires electric power generated by a solar power generation device () on the basis of power consumption (W) of the communication device () and output power (P′) of the rectifier (). A search operation voltage decision unit () decides a rectifier voltage of the rectifier () using a sign of a search voltage (dv) decided by a sign inversion unit () so that the electric power generated by the solar power generation device () is increased.