Fuel cell stack state diagnosis method and fuel cell system control method

摘要

A system and method for diagnosing the state of a fuel cell stack are provided. The method includes simultaneously applying currents having respective first and second frequencies to a fuel cell stack and computing Fourier transforms of output currents and voltages from the fuel cell stack based on the applied currents. A real part of a first frequency impedance and an imaginary part of a second frequency impedance are calculated using amplitudes and phases of currents and voltages having the first frequency and the second frequency among the computed output currents and voltages. Further, a state of the fuel cell stack is determined by magnitude of the calculated real part of the first frequency impedance and by magnitude of the calculated imaginary part of the second frequency impedance.