Patent ID: 7354671

Claim:
A power supply system for supplying electrical power to a load, comprising: a power supply wiring for a connection to the load; a fuel cell system including a fuel cell connectable to the power supply wiring; a secondary power supply system connectable to the fuel cell via the power supply wiring; a switch for opening and closing a connection between the fuel cell and the power supply wiring; and a controller for controlling the secondary power supply system and the switch, wherein the controller is configured to control the secondary power supply system to boost a terminal voltage of the secondary power supply system to a first voltage, when connecting the fuel cell to the power supply wiring, the first voltage being equal or higher than an open circuit voltage of the fuel cell, and the controller is configured to drop the terminal voltage of the secondary power supply system to a voltage lower than an electrical potential difference of the fuel cell, in response to isolation of the fuel cell from the power supply wiring by turning the switch off.