Patent ID: 7757668

Claim:
A method of controlling a flow rate of fuel in a fuel supply unit of a fuel cell system, the method comprising: supplying fuel using a fuel pump to a reformer reforming the fuel to generate hydrogen for a stack of the fuel cell system generating electric energy through a reaction of the fuel and oxygen, wherein the fuel cell system comprises the fuel pump, a revolution per minute (RPM) measuring unit, a microcomputer, and a power converter; measuring an actual RPM of the fuel pump by detecting an RPM of the fuel pump at a plurality of times to obtain a plurality of detection values and averaging the plurality of detection values to obtain the actual RPM of the fuel pump; directly comparing the actual RPM to a reference RPM of the fuel pump; and adjusting a driving voltage of the fuel pump on the basis of a result obtained by directly comparing the actual RPM to the reference RPM of the fuel pump.