Understanding PEM fuel cell dynamics: The reversal curve. (15th June 2017) - Peña Arias, Ivonne Karina
Abstract: In this contribution the reversal line, a new voltage–current ( U–i ) characteristic curve, is proposed to analyze the transient behavior after an arbitrary load step. The response of a differential polymer electrolyte membrane (PEM) fuel cell to the changes in current, voltage, resistance and power is evaluated, and the existence of the curve is established. Furthermore, the influence of the starting point and the relative humidity is investigated. By using this approach, it is possible to predict the trajectory followed after any load step in the U–i plane and to anticipate infeasible load steps as well as the presence and magnitude of overshoots or undershoots in the cell response. Highlights: Load steps are systematically carried out for the four possible control modes, namely: current, voltage, power and resistance. A new approach to describe the dynamic response of a PEM fuel cell after an arbitrary load step is proposed. With our approach one can predict the trajectories followed after any load step and anticipated dynamically infeasible points.