Model-based control design for H 2 purity regulation in high-pressure alkaline electrolyzers

DAVID, MARTÍN; BIANCHI, FERNANDO; OCAMPO-MARTINEZ, CARLOS; SÁNCHEZ-PEÑA, RICARDO

JOURNAL OF THE FRANKLIN INSTITUTE

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2021 vol. 358 p. 4373 - 4392

0016-0032

This paper proposes two control strategies that mitigate the cross contaminationof H2 and O2 in a high-pressure alkaline electrolyzer, which consequentlyincreases the supplied gases purity: one based on a decoupled PIscheme and the other based on optimal control tools. In order to reducethe diffusion of gases through the membrane, the controllers establish theopening of two outlet valves based on the pressure of the system and thedifference in liquid level between both separation chambers. Therefore, twomultiple input - multiple output controllers are designed here. For this purpose,a high-fidelity model previously developed was simplified in order toobtain a control-oriented model. The proposed controllers were evaluated insimulation using the high-fidelity nonlinear model in a wide operating range,which resulted in less than 1% impurity of gases.