Patent ID: 8574777

Claim:
A fuel cell system comprising: a fuel cell; a load which operates owing to a power of the fuel cell; a first voltage conversion device which is provided between the fuel cell and the load and which converts an output of the fuel cell into a voltage to supply the voltage to the load, the first voltage conversion device being a booster converter; an adjustment device which adjusts an amount of a reactant gas to be fed to the fuel cell; and a controller programmed to: operate the fuel cell at a low-efficiency operation point having a power loss larger than that of a usual operation point in a case where a warm-up operation of the fuel cell is required or an operation of recovering a catalyst activity of the fuel cell is required; control a voltage converting operation of the first voltage conversion device based on the operation point of the fuel cell and a driving voltage of the load to raise a terminal voltage of the fuel cell to at least the driving voltage of the load; and control the fuel cell voltage and fuel cell current to realize the shift of the operation point from the usual operation point to the low-efficiency operation point, while maintaining fuel cell power output constant, by lowering the fuel cell voltage with the booster converter and adjusting the amount of reactant gas fed to the fuel cell in order to control the fuel cell current.