On the application of sliding mode control to indirectly coupled photovoltaic-electrolyzer systems used in the production of clean energy

To improve the performance of photovoltaic-electrolyzer (PV-EL) systems, it is key to operate them at the right operating conditions, not only at design point but also at off-design. In addition, when directly coupling a PV system to an EL one, an ideal sizing of the resulting PV-EL coupled system ensuring the best interaction between the PV system and the EL stack is not always possible. Coupling indirectly PV systems to EL ones, through DC/DC converters for instance, results thus advantageous. Accordingly, this work discusses the application of sliding mode control (SMC) to indirectly coupled PV-EL systems, which allows them to operate as efficient as possible. The control scheme employed here includes mathematical models for both the PV system and the EL stack, and for the DC/DC converter and the sliding mode control algorithm utilized. To determine their influence on the obtained results, two different converter topologies are assessed here. Some of the results obtained emphasize that using a DC/DC converter can significantly increase the hydrogen produced by PV-EL systems, especially when it is paired with a control algorithm like SMC. This effort represents one of the first works involving the application of sliding mode control to indirectly coupled PV-EL systems.