Currently, tracking in photovoltaic (PV) systems suffers from some problems such as high energy consumption, poor anti-interference performance, and large tracking errors. This paper presents a solar PV tracking system on the basis of an improved perturbation and observation method, which maximizes photoelectric conversion efficiency. According to the projection principle, we design a sensor module with a light-intensity-detection module for environmental light-intensity measurement. The effect of environmental factors on the system operation is reduced, and intelligent identification of the weather is realized. This system adopts the discrete-type tracking method to reduce power consumption. A mechanical structure with a level-pitch double-degree-of-freedom is designed, and attitude correction is performed by closed-loop control. A worm-and-gear mechanism is added, and the reliability, stability, and precision of the system are improved. Finally, the perturbation and observation method designed and improved by this study was tested by simulated experiments. The experiments verified that the photoelectric sensor resolution can reach 0.344°, the tracking error is less than 2.5°, the largest improvement in the charge efficiency can reach 44.5%, and the system steadily and reliably works.
Hydrogen is believed to be one of the essential clean secondary energy sources in the energy structure revolution of both industry and daily life. Driven by renewable electricity such as solar and wind power, water electrolysis for hydrogen production is deemed as one of the main processes of green hydrogen production in the future by both academia and industry. Transition metal chalcogenides (TMCs) are promising candidates to replace noble metals as earth-abundant electrocatalysts for water splitting. However, it remains challenging to further improve the electrocatalytic activity and long-term stability of TMCs, especially in a practical water electrolyzer. This Review summarizes the recent advances and the strategies of optimizing the electrocatalytic activities of TMCs toward water splitting as well as the latest investigations on the surface reconstructions of TMCs during water electrolysis. The performances of TMCs in practical electrocatalytic water splitting cells are particularly discussed. Finally, a concluding remark and perspective is provided, and we hope to inspire future works in this area, narrowing the gap between material design and practical application.
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