POWER SUPPLY SYSTEM, AND VOLTAGE CONTROL METHOD FOR FUEL CELL

摘要

Provided are a power supply system and a voltage control method for a fuel cell, for maintaining a voltage of the fuel cell within a proper range when a load demand is extremely small. The voltage control method for a fuel cell (100) includes the steps of: interrupting electrical connection between the fuel cell and a load (170,172) in a low load state; supplying oxygen to the fuel cell in a preset condition during the interruption of the electrical connection; detecting an open circuit voltage (OCV) of the fuel cell after supplying the oxygen to the fuel cell in the preset condition; reducing an amount of the oxygen supplied to the fuel cell when the OCV is higher than a target voltage by a first value or larger; increasing the amount of the oxygen supplied to the fuel cell when the OCV is lower than the target voltage by a second value or larger; and maintaining the amount of the oxygen supplied to the fuel cell when the OCV is lower than a sum of the target voltage and the first value, and higher than a value obtained by subtracting the second value from the target voltage.