Patent ID: 7436148

Claim:
A method of determining voltage conditions of a fuel cell vehicle, wherein: the fuel cell vehicle includes: a motor as a driving force source of the vehicle, a motor control device for controlling operation of the motor, a fuel cell, to which a reaction gas is supplied, for generating electric power by an electrochemical reaction, and a battery device which is charged by the electric power generated by the fuel cell and sends and receives electrical energy to and from the motor by control of the motor control device; a voltage conversion device, which comprises a chopper DC-DC converter, for increasing or decreasing a terminal voltage of the battery device and outputting the converted voltage, wherein the battery device and the DC-DC converter are connected to the fuel cell in parallel; and a control device for outputting a control pulse to the DC-DC converter, wherein the fuel cell and the battery device are directly connected to each other via the DC-DC converter when the duty ratio of the control pulse is set to 100%; and the method includes setting an average of an output voltage of the fuel cell within a range from a minimum value to a maximum value of an open circuit voltage of the battery device.