Optimization of A Stand-Alone Solar Photovoltaic Direct-Coupled Alkaline Water Electrolysis Setup by Experiment Method and Simulink Modeling

Photovoltaic water electrolysis hydrogen production technology has garnered significant attention due to its zero carbon emissions and its potential to address the issue of grid fluctuations associated with solar power generation. However, the direct coupling technology for photovoltaic electrolyzer system remains underdeveloped, leading to the predominance of indirect coupling methods. This limitation results in a low overall conversion efficiency, which significantly hinders the application and promotion of this technology. In this paper, we first constructed a set of miniaturized photovoltaic water electrolysis devices, utilizing commercial photovoltaic modules and self-manufactured electrolyzer, and subsequently tested the operational characteristics of both components. Based on the experimental results, we established a simulation model for direct coupling of photovoltaic water electrolysis. This model incorporates the concept of supplying photovoltaic power to the electrolytic cells through DC conversion via an MPPT controller. This approach is deemed more operationally feasible compared to traditional series-parallel adjustment methods for electrolytic cells. The experimental findings also indicate that the series connection of electrolytic cells is necessary, with the number of cells not being too small to avoid fluctuations. In this paper, a configuration of six cells was selected as the final optimization solution. Additionally, we tested the adaptability of the system across a wide range of radiation intensities. The experimental results demonstrate that the proposed solution and configuration can effectively adapt to variations in radiation intensity.