Fuel cell system and control method of the same

A control method fuel cell system having:

• a fuel cell;
• an FC converter provided as a DC-DC converter and connected with the fuel cell at an input side thereof and with a main wiring on an output side thereof;
• a secondary battery;
• a battery converter provided as a DC-DC converter, connected between the secondary battery and the main wiring, and configured to include a smoothing capacitor for boosting on a main wiring side thereof;
• a battery sensor configured to measure a temperature of the secondary battery;
• a voltage sensor configured to measure a voltage of the smoothing capacitor;
• a cathode gas supply system configured to include a compressor that is operated with supply of electric power from the main wiring and to supply a cathode gas to the fuel cell;
• and an anode gas supply system configured to include a main stop valve that is operated with supply of electric power from the secondary battery and to supply an anode gas to the fuel cell;
• the control method comprising the steps of:
• receiving an instruction to start power generation of the fuel cell system, the controller is configured;
• obtaining an output limit value of the secondary battery according to a predetermined relationship of the temperature of the secondary battery to the output limit value of the secondary battery by using the temperature of the secondary battery;
• controlling the battery converter such as to increase the voltage of the smoothing capacitor to a start-time target voltage that is higher than an open circuit voltage of the fuel cell, such that an output power of the secondary battery does not exceed the output limit value;
• and
• operating the compressor such as to start supplying the cathode gas by the cathode gas supply system and to open the main stop valve such as to start supplying the anode gas by the anode gas supply system, after the voltage of the smoothing capacitor becomes equal to or higher than the start-time target voltage, to