FUEL CELL SYSTEM

摘要

When the operation point of a DC/DC converter (60), which steps up/down the output voltage of a fuel cell stack (20), is in a range of reduction in response capability and further there is issued a request of determining an AC impedance, a controller (80) switches numbers of the drive phases of the DC/DC converter (60) to determine an AC impedance of the fuel cell stack (20). If the operation point of the DC/DC converter (60) is in the range of reduction in response capability and further the precision of determining the AC impedance is reduced, then the determination of AC impedance in the range of reduction in response capability is inhibited and the switching of the phases of the DC/DC converter (60) is implemented, thereby causing the operation point of the DC/DC converter (60) to be out of the range of reduction in response capability, with the result that the precision of determining the AC impedance can be raised.