H∞ control experiments for increasing H2 purity in high-pressure alkaline electrolyzers

In this paper, an H∞ control strategy is implemented in a prototype alkaline electrolyzer to maintain equalized the liquid levels in the separations chambers while following a pressure reference. The aim is to minimize the contamination of the gases produced by the electrolyzer. To this end, two outlet valves are controlled in the output lines of both gases: H2 and O2. The performance of the proposed control strategy was experimentally evaluated under different operating conditions. In all cases, H2 contamination in O2 was below 0.2%.