Research on Online Diagnosis Method of Fuel Cell Centrifugal Air Compressor Surge Fault

Stable operation of fuel cell air compressions is constrained by rotating surge in low flowrate conditions. In this paper, a diagnosis criterion based on wavelet transform to solve the surge fault is proposed. First of all, the Fourier transform was used to analyze the spectral characteristics of the outlet flowrate. Before wavelet transform was used, the data are standardized. This step eliminated the influence of the flowrate’s absolute value. Then, the wavelet coefficients under characteristic frequencies were extracted. Finally, the diagnosis criterion’s threshold, which indicates the surge occurrence, was defined from the perspective of safety margin. The criterion threshold alerted a surge only 1 s after it occurred. The analysis results show that the criterion meets with the expectation, and it can be used for the control of anti-surge valve.