Online monitoring of fuel starvation and water management in an operating polymer electrolyte membrane fuel cell by a novel diagnostic tool based on total harmonic distortion analysis

The present study deals with a novel diagnostic tool for fuel and water management problems by analyzing the harmonics on an operating polymer electrolyte membrane fuel cell. In this method, a low frequency signal is applied to the fuel cell and the total harmonic distortion contained in the resulting signal is observed under different conditions. The total harmonic distortion is used to monitor and identify the conditions online such as anode drying, anode flooding, hydrogen starvation and cathode flooding prevailing in the cell. This is done by identifying a set of indicator frequencies correspond to the aforementioned critical conditions. Through empirical studies, it is shown that frequency responses lead to a high total harmonic distortion value indicating critical conditions and provide an accurate diagnostic method to detect an even slightly degraded state. These results successfully demonstrate the promise of the proposed method in overcoming performance losses by efficient online monitoring of fuel cells. The relation between the health of the fuel cell and the variations in the harmonics present in the studied signal is characterized and utilized for the diagnostic studies of polymer electrolyte membrane fuel cell.