METHOD FOR DIAGNOSING STATE OF FUEL CELL STACK AND METHOD FOR CONTROLLING FUEL CELL SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a method for diagnosing a state of a fuel cell stack and a method for controlling a fuel cell system.SOLUTION: A method for diagnosing a state of a fuel cell stack of the present invention includes the steps of: simultaneously applying currents having respective first and second frequencies to a fuel cell stack; applying a Fourier transform to currents and voltages output from the fuel cell stack in accordance with the applied currents; calculating a real part of a first frequency impedance and an imaginary part of a second frequency impedance using amplitudes and phases of currents and voltages having the first frequency and the second frequency among the transformed output currents and voltages; and diagnosing a state of the fuel cell stack depending on the magnitude of the calculated first frequency impedance and the magnitude of the calculated second frequency impedance. In the method, the first frequency is greater than the second frequency.