Application of photovoltaics to hydrogen production: dynamics, modeling and control

GARCÍA CLÚA, J.; MANTZ, R.; DE BATTISTA, H.

Photovoltaics: Developments, Applications and Impact

Nova Science Publishers

Lugar: New York; Año: 2010; p. 195 - 212

Nowadays, it is very common to find photovoltaic energy conversion systems integrated to isolated power systems. Short-term and seasonal variability of the primary resource and power demand detracts from the efficiency of these autonomous installations. In this context, hydrogen storage appears as a very attractive option to overcome this problem. From another point of view, solar energy appears as one of the most attractive renewable resources for the sustainable and green production of hydrogen via electrolysis. Currently, there are many research and technical projects oriented to the development of renewable-powered hydrogen production plants. In this context, this work focuses on an autonomous hydrogen production system basically consisting in a photovoltaic generator supplying an electrolyzer. Following the current tendency of eliminating component duplication, these devices are not connected ?with dedicated power electronics? to a common DC bus, but directly through a single DC-DC converter. This converter is aimed at adjusting the output voltages of the solar array and electrolyzer in order to maximize hydrogen production. In addition to the efforts to  reduce the costs of associated technologies, the development of suitable modeling techniques and high performance controllers are needed for cost?competitive hydrogen production by solar-powered electrolysis. Given the architecture and operation of solar?hydrogen power systems, the dynamic behavior can be described by a discrete dynamics that capture the different modes of operation of the system, each of them having its own continuous dynamics. In view of this hybrid structure, the hybrid system theory appears as a suitable approach to the study of the system dynamics. With this motivation, this work applies concepts of hybrid systems to the modeling, dynamic analysis and control design of a solar?hydrogen power plant.