Patent ID: 8212516

Claim:
A power supply system in which a fuel cell is connected to an input terminal of a direct-current voltage converter and a load and electric energy storage means are connected to an output terminal of the direct-current voltage converter in parallel, the power supply system comprising measurement means configured to measure terminal voltage of said electric energy storage means and control means that sets target output voltage of the direct-current voltage converter based on the terminal voltage, wherein said target output voltage is set higher than the terminal voltage, said fuel cell is operated within a predetermined power generation condition, if power that is generated by said fuel cell and output via said direct-current voltage converter is higher than power consumption of said load, charge of said electric energy storage means by said direct-current voltage converter is automatically performed and output voltage of said direct-current voltage converter is kept at a charge voltage of said electric energy storage means, and if power that is generated by said fuel cell and output via said direct-current voltage converter is lower than power consumption of said load, discharge from said direct-current voltage converter to said load is automatically performed and output voltage of said direct-current voltage converter is kept at discharge voltage of said electric energy storage means wherein; by power that is generated by said fuel cell and output via said direct-current voltage converter, a charge mode in which only charge of said electric energy storage means is performed, a charge-and-drive mode in which charge of said electric energy storage means and power supply to said load are performed, and a drive mode in which only power supply to said load is performed are carried out, and by power that is generated by said fuel cell and output via said direct-current voltage converter and discharge output of said electric energy storage means, a discharge mode in which power supply to said load is performed is carried out.