Fuel cell system

A fuel cell system comprising:

• a fuel cell;
• a supply channel for supplying, to the fuel cell, a fuel gas supplied from a fuel supply source;
• a single variable gas supply device for adjusting a gas state on an upstream side of the supply channel to supply the gas to a downstream side;
• a computer system including a control section programmed to perform proportional and integral (PI) control of a gas supply command amount with respect to the variable gas supply device;
• an abnormality judgment section programmed to judge whether or not the variable gas supply device is abnormal;
• a current sensor for detecting a current during a power generation by the fuel cell;
• and
• a pressure sensor for detecting a pressure of the fuel gas in the supply channel, the pressure sensor provided on the downstream side of the variable gas supply device,
• wherein the control section is programmed to use, as a part of a correction term of the PI control, a learning term constituted by integrating an integral (I) term only in a case where an operation state of the fuel cell satisfies predetermined learning allowable conditions, the predetermined learning allowable conditions are satisfied when a generated current of the fuel cell detected by the current sensor is larger than a predetermined generated current value and a change of the generated current is stable within a predetermined range,
• wherein the abnormality judgment section is programmed to judge, based on the learning term, whether or not the variable gas supply device is abnormal,
• wherein the I term of the PI control is calculated by integrating a feedback value corresponding to a deviation between a pressure value detected by the pressure sensor downstream of the supply device and a target pressure value, and
• wherein the I term of the PI control is integrated for each of a plurality of learning zones, the plurality of learning zones being constituted by dividing a demanded jet flow rate of the variable gas supply device for each of a plurality of predetermined flow rates.