Photovoltaic power generation: According to the principle of photovoltaic effect, solar energy is directly converted into electric energy by using solar cells. Whether it is used independently or connected to the grid, the photovoltaic power generation system is mainly composed of solar panels (modules), controllers and inverters, mainly composed of electronic components, and does not involve mechanical parts.
Photovoltaic power generation is a technology that directly converts light energy into electric energy by using photovoltaic effect of semiconductor interface. The key part of this technology is solar cells. After the solar cells are connected in series, they can be packaged and protected to form a large-area solar cell module, and then form a photovoltaic power generation device with power controllers and other components.
Photovoltaic power generation system is divided into independent photovoltaic power generation system, grid-connected photovoltaic power generation system and distributed photovoltaic power generation system.
1, independent photovoltaic power generation is also called off-grid photovoltaic power generation. It is mainly composed of solar cell module, controller and storage battery. In order to supply power to AC load, it is necessary to configure AC inverter. Independent photovoltaic power stations include village power supply system, solar household power supply system, communication signal power supply, cathodic protection, solar street lamps and other photovoltaic power generation systems with batteries that can operate independently.
2. Grid-connected photovoltaic power generation means that the direct current generated by solar cell modules is converted into alternating current meeting the requirements of commercial power grid through grid-connected inverter, and then directly connected to commercial power grid.
Examples of photovoltaic power generation
It can be divided into grid-connected power generation systems with and without batteries. Grid-connected power generation system with storage battery is schedulable, can be integrated into or withdrawn from the power grid as required, and also has the function of standby power supply, which can provide emergency power supply when the power grid fails for some reason. Photovoltaic grid-connected power generation systems with storage batteries are often installed in residential buildings; Battery-free grid-connected power generation systems do not have the functions of schedulability and standby power supply, and are generally installed on larger systems. Grid-connected photovoltaic power generation has centralized large-scale grid-connected photovoltaic power stations, which are generally state-level power stations. The main feature is that the generated energy is directly transmitted to the power grid, and the power grid uniformly distributes electricity to users. However, this kind of power station has large investment, long construction period, large area and little development. However, decentralized small-scale grid-connected photovoltaic power generation, especially photovoltaic building integrated photovoltaic power generation, is the mainstream of grid-connected photovoltaic power generation because of its advantages of small investment, fast construction, small area and strong policy support.
3. Distributed photovoltaic power generation system, also known as distributed power generation or distributed energy supply, refers to configuring a small photovoltaic power supply system at the user site or near the power consumption site to meet the needs of specific users, support the economic operation of the existing distribution network, or meet both requirements.
The basic equipment of distributed photovoltaic power generation system includes photovoltaic cell module, photovoltaic array, DC junction box, DC distribution cabinet, grid-connected inverter, AC distribution cabinet and other equipment, as well as power supply system monitoring device and environmental monitoring device. Its operation mode is that in the case of solar radiation, the solar cell module array of photovoltaic power generation system sends the electric energy converted from solar energy to DC distribution cabinet through DC junction box, which is converted into alternating current by grid-connected inverter to supply the building's own load, and the excess or insufficient electricity is adjusted by connecting to the power grid.