Analysis and control strategy design for PEMFC purging process

Abstract

In this study, a lumped-parameter model for shutdown purging has been developed using MATLAB/Simulink®. Data gleaned from actual operational scenarios on a fuel cell experimental platform serve as the basis for parameter identification within the model. The study encompasses a comparative analysis of purging processes under various operational parameters, including stack temperatures, purging currents, and purging flow rates. Moreover, an innovative purging strategy is proposed, employing an open-loop control mechanism to modulate the purging flow rate. The analysis reveals that an elevated stack temperature and a reduced purging current markedly enhance purging efficiency and diminish the water content at equilibrium. A negative correlation is observed between purging time and purging flow rate, with energy consumption demonstrating a U-shaped pattern across different flow rates. According to the proposed purging strategy, the optimal purging flow rate is ascertained through a Multi-dimensional Array Programming (MAP) lookup. This lookup is contingent upon stack temperature, purging current, and initial membrane water content. Validation confirms that this strategy not only truncates the purging duration but also curtails the system energy expenditure. These analytical insights and the newly-formulated purging strategy hold both theoretical and pragmatic implications for optimizing stack shutdown purging operations and advancing future purging methodologies.