Model-based control design for H2 purity regulation in high-pressure alkaline electrolyzers

•The aim is to mitigate gas contamination in a high-pressure alkaline electrolyzer.•Control strategies proposed: a decoupled PI scheme and a multivariable optimal control.•Two valves are controlled based on the pressure and level difference.•A model previously developed was simplified to obtain a control-oriented model.•The controllers were tested in simulation and both gas impurities were below 1%.