Recovery control system of fuel cell and method thereof

A recovery control system of a fuel cell, comprising:

• a) a fuel cell comprising a plurality of unit cells;
• b) an air supplier configured to supply air to the fuel cell;
• c) an abnormality sensing unit configured to calculate a difference between a reference cell voltage redetermined depending on an output current of the fuel cell and a measured cell voltage of the plurality of unit cells and to sense abnormality of air supply to a fuel cell stack based on the calculated difference between the reference cell voltage and the measured cell voltage or change in the difference between the reference cell voltage and the measured cell voltage;
• and
• d) a recovery controller configured to control the air supplier so as to increase a flow rate of air supplied to the fuel cell stack based on the change in the difference between the reference cell voltage and the measured cell voltage, when the abnormality sensing unit senses abnormality of air supply;
• a battery charged with the electric power generated by the fuel cell so as to store the electric power, or discharged so as to supplement the electric power generated by the fuel cell;
• and
• a converter disposed between the fuel cell and the battery so as to convert the electric power, wherein:
• the abnormality sensing unit senses abnormality of voltage control of the converter based on the change in the difference between the reference cell voltage and the measured cell voltage when the output current of the fuel cell decreases;
• and
• the recovery controller controls the converter so as to increase a fuel cell-side voltage of the converter when the abnormality sensing unit senses abnormality of voltage control.

A recovery control method of a fuel cell, comprising:

• calculating a difference between a reference cell voltage predetermined depending on an output current of the fuel cell and a measured cell voltage of unit cells in the fuel cell;
• sensing abnormality of air supply to a fuel cell stack based on the calculated difference between the reference cell voltage and the measured cell voltage or change in the difference between the reference cell voltage and the measured cell voltage;
• and
• controlling an air supplier so as to increase a flow rate of air supplied to the fuel cell stack based on the change in the difference between the reference cell voltage and the measured cell voltage, when abnormality of air supply is sensed;
• wherein, in the controlling the air supplier, a rate of increase of a rotational speed of the air supplier is controlled by applying a ratio between a previous value and a current value of the difference between the reference cell voltage and the measured cell voltage.