Model-based fuel pressure regulation algorithm for a hydrogen-injected PEM fuel cell engine

Abstract

In Polymer Electrolyte Membrane Fuel Cells (PEMFCs) with Dead-Ended Anode (DEA) configuration, precise control of hydrogen pressure in anode is beneficial for better performance and durability of fuel cell systems. In most studies, mechanical pressure regulator is implemented to modulate the hydrogen pressure. But when load changes or purge operation activates, hydrogen pressure downstream the regulator varies with hydrogen flow fluctuation. In this study, a hydrogen injection system is developed utilizing gaseous fuel injectors. Based on a fuel cell simulation test bench, the performance of the hydrogen injection system is evaluated. A physics-based nonlinear model of the simulation test bench is presented in this paper. Experimental results validate the model. The model is further linearized and integrated in a Robust Predictive Controller (RPC), a Model-Based Controller (MBC), and an H∞ controller, respectively, in order to compare the control effects on the hydrogen pressure, especially the mitigation of the pressure swing during the purge operation. A comparative study is carried out under different scenarios, i.e. target pressure step response, hydrogen consumption mass flow step response, and periodical pulse response during the purge operation. According to the results, MBC is chosen for injection control, since the system demonstrates preferable performance in comparison with other controllers. Finally, pressure fluctuation data of both simulation test bench with hydrogen injection and conventional mechanical pressure regulator is compared to elucidate the effectiveness.