Green hydrogen is the term used to reflect the fact that hydrogen is generated from renewable energies. This process is commonly performed by means of water electrolysis, decomposing water molecules into oxygen and hydrogen in a zero emissions process. Proton exchange membrane (PEM) electrolyzers are applied for such a purpose. These devices are complex systems with non-linear behavior [1,2] which impose the measurement and control of several magnitudes for an effective [3] and safe operation [4]. In this context, the modern paradigm of digital twin is applied to represent and, even, predict the electrolyzer behavior under different operating conditions. To build this cyber replica, a paramount previous stage consists of characterizing the device by means of the curves that relate current, voltage and hydrogen flow. To this aim, this paper presents a processes supervision system focused on the characterization of a modular experimental PEM electrolyzer. This device is integrated in a microgrid for production of green hydrogen using photovoltaic energy [5]. Three main functions must be performed by the supervision system: measurement of the process magnitudes, data acquisition and storage, and real-time visualization [6,7]. To accomplish these tasks, firstly, a set of sensors measure the process variables. In second place, a programmable logic controller is responsible of acquiring the signals provided by the sensors. Finally, LabVIEW implements the user interface as well as data storage functions. The process evolution is observed in real-time through the user interface composed by graphical charts and numeric indicators. This way, the operator is informed about the process status in a continuous and user-friendly manner, being data stored for further development of the digital twin. The deployed process supervision system is reported together with experimental results to prove its suitability.

References

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