In the context of global energy transition, photovoltaic power generation, as a clean and renewable energy technology, is gradually becoming an important force in the energy field. In this paper, we will discuss in depth the principles, system components, application areas and future development trends of photovoltaic power generation technology.
First, principle of photovoltaic power generation
Photovoltaic power generation is based on the photovoltaic effect, that is, when sunlight irradiates the semiconductor material, photons interact with the electrons in the material, so that the electrons get enough energy to escape, forming a photovoltaic current. The core component of photovoltaic power generation is the photovoltaic cell, which usually consists of two layers of different types of semiconductor materials, such as p-type semiconductors (with more holes) and n-type semiconductors (with more free electrons). Under light, photons are absorbed and electron-hole pairs are released. Due to the electric field in the semiconductor, the electrons and holes are separated to the two sides of the p-n junction, resulting in a potential difference and an electric current, which realizes the direct conversion of solar energy into electricity. In order to improve the power generation efficiency of photovoltaic cells, often using poly-crystalline silicon, mono-crystalline silicon, amorphous silicon and other different materials used in the manufacture of photovoltaic cells, but also the use of multi-stage bonding technology, optical enrichment technology, and other measures to improve the efficiency of light absorption and the collection of electrons.
Second, the composition of photovoltaic power generation system
Solar panel: As the key part of the solar energy into direct current electricity, composed of multiple solar cells, each solar cell is made of silicon, phosphorus, boron and other semiconductor materials. When the sunlight shines on the solar panel, it can convert sunlight into direct current electricity. Its color is usually blue or black.
Inverter: Responsible for converting the DC power generated by the solar panels into AC power that meets national standards for input to the grid or for direct use by electrical loads. The inverter is usually equipped with light control, power control, fault protection and other functions to ensure the stability and safety of power conversion.
Controller: As the core of managing the PV power generation system, it can precisely control the charging and discharging process of solar panels and batteries, and at the same time monitor and regulate the operation status of the inverter in real time, so as to realize the reasonable distribution and efficient utilization of electric energy.
Battery pack: It is used to store the electricity generated by solar power generation, and provide a continuous and stable power supply for the system when the solar panels are unable to generate electricity (e.g. at night, cloudy days, etc.). Common battery types include lead-acid batteries, nickel-cadmium batteries, lithium-ion batteries, etc.
Racking: As the support structure of solar panels, it is usually made of aluminum alloy, stainless steel and other materials, with wind resistance, shock resistance, corrosion resistance and other characteristics, to ensure stable operation in a variety of harsh environments. The mounting location of the bracket is usually chosen on the roof, wall, parking lot, etc. of the building, which needs to have good load-bearing capacity and stability.
Cables: In PV systems, cables are used for power transmission, signal transmission and connection of remote monitoring equipment. Cables are usually made of copper or aluminum, with good conductivity and high temperature resistance, and need to be installed in strict accordance with electrical specifications to ensure electrical safety and reliability.
Third, the application areas of photovoltaic power generation
Rooftop photovoltaic power generation system: Solar panels are installed on the roof of a building to convert solar energy into electricity for use in the building. This application is applicable to all types of buildings such as residential, commercial buildings, industrial plants, etc. It not only reduces energy costs, but also helps to reduce dependence on traditional energy sources and realize green energy saving.
Public facilities and municipal projects: Widely used in public buildings, road lighting, traffic signals and other public facilities and municipal projects to provide reliable power supply for these projects. In some regions, the government has also introduced a series of incentive policies to further promote the application and development of PV power generation in the public sector.
Distributed Power Generation: Distributed PV power generation is a PV power generation system that is decentralized on the user's side of the electricity supply, converting DC power to AC power through inverters, and then connecting to the local power system to achieve self-sufficiency or grid-connected power supply. This type of power generation can connect the PV power station to the community, industrial area, etc., to provide a more flexible energy supply, and effectively reduce the loss of energy transmission process.
Centralized photovoltaic power generation: Centralized photovoltaic power generation system can be directly connected to the solar energy grid, the grid unified power supply configuration, belongs to the one-way exchange type. Centralized large and medium-sized grid-connected photovoltaic power station is mainly characterized by large capacity, high grid voltage level, the power generated will be directly transmitted to the grid, by the grid unified deployment of power supply to the user. Due to their large scale, they usually need to be built on wide open spaces, such as deserts and wildernesses. Although the construction requires a large amount of capital and land resources, the scale advantage makes it possible to obtain high power generation efficiency and cost-effectiveness .
Fourth,the future development trend of photovoltaic power generation technology
Innovation and breakthroughs in photovoltaic materials: With the continuous progress of materials science, new photovoltaic materials such as chalcogenide materials, organic - inorganic hybrid materials continue to emerge. These materials have higher photoelectric conversion efficiency and lower cost, and are expected to become the key force driving the further development of photovoltaic technology.
Continuous optimization of PV cell structure and design: Researchers will further improve the conversion efficiency and stability of PV cells through in-depth study and optimization of cell structure, surface morphology and optical properties. For example, the use of advanced technologies such as nano-structural design and light-trapping structures can effectively improve the efficiency of PV cells in absorbing and utilizing sunlight.
Photovoltaic system integration and intelligent development: In the future, the integration of photovoltaic cells with other energy systems (e.g., wind energy, energy storage, etc.) to achieve efficient use of energy and complementarity will become an important trend. At the same time, with the help of Internet of Things, big data analysis and other intelligent technologies, real-time monitoring and optimization of the PV system will be realized to improve the operational efficiency and reliability of the system.
The deep integration of PV technology and buildings: Buildings are one of the major areas of energy consumption, and building integrated photovoltaic (BIPV) will become an important development direction in the future. By integrating photovoltaic cells into the exterior walls and roofs of buildings, it can not only provide clean energy for the buildings, but also effectively improve the appearance and energy-saving performance of the buildings, realizing the perfect integration of buildings and energy.
Global promotion and cooperation: Global promotion and cooperation of PV technology is crucial for its future development. Strengthening international cooperation and sharing research results and technical experience can accelerate the rapid development and widespread popularization of PV technology. At the same time, governments should also increase their support for the PV industry and formulate reasonable policies and regulations to create a favorable environment and conditions for the promotion and application of PV technology.
In conclusion, photovoltaic power generation technology, with its clean, renewable, pollution-free and other significant advantages, has shown great potential for development in the field of energy. With the continuous progress and innovation of technology, photovoltaic power generation technology will occupy a more important position in the future energy structure and make a positive contribution to the global sustainable energy development.
