Design and Realization of a Stacked Interleaved DC-DC Step-Down Converter for PEM Water Electrolysis with Improved Current Control

In order to face the intermittent nature of renewable energy sources (RES), hydrogen production and storage are considered an attractive solution. Nowadays, RES (e.g., wind, photovoltaic), and fossil fuels (e.g., coal, natural gas) are the various resources available on the planet Earth to produce hydrogen. Water electrolysis is one of the most interesting ways of producing hydrogen from RES; this electrochemical reaction is realized through an electrolyzer. Usually, DC-DC step-down converters are used in the hydrogen production systems since electrolyzers must be supplied with a very low DC voltage to generate hydrogen from deionized water. Although these converters are widely used, they have several drawbacks from output current ripples and energy efficiency point of view. In order to meet the requirements for electrolyzer applications, a stacked interleaved DC-DC step-down converter has been used to carry out this work. The objective of this paper is to develop a control law of the studied converter based on the current flowing through in one of the phases. This control allows reducing phase current overshoot and oscillations, and consequently conduction losses. Finally, by an experimental investigation, the performance of the current controller from overshoot, stability and oscillation point of view has been assessed.