Solar power generation system is divided into off-grid power generation system, grid-connected power generation system and distributed power generation system.
The off-grid power generation system is mainly composed of solar cell modules, controllers and batteries. If the output power supply is AC 220V or 110V, an inverter is also required. The role of each part is: (1) solar panels: solar panels are the core part of the solar power generation system, but also the most valuable part of the solar power generation system. Its role is to convert the sun's radiation capacity into electrical energy, or sent to storage batteries, or to promote the load work.
(2) solar controller: the role of the solar controller is to control the working state of the whole system, and the battery overcharge protection, overdischarge protection. In the place of large temperature difference, the qualified controller should also have the function of temperature compensation. Other additional functions such as light control switches and time control switches should be optional for the controller;
(3) Battery: generally lead-acid battery, small and micro system, can also be used nickel metal hydride battery, nickel cadmium battery or lithium battery. The idea is to store the electricity generated by the solar panels when the light is on and release it when needed.
(4) Inverter: the direct output of solar energy is generally 12VDC, 24VDC, 48VDC. To supply electricity to 220VAC appliances, the direct current energy from the solar power system needs to be converted into AC power, so DC-AC inverters are used.
Grid-connected power generation system refers to the direct current generated by solar modules that is converted by grid-connected inverter into alternating current that meets the requirements of the mains power grid and then directly connected to the public power grid. There are centralized large-scale grid-connected power stations in the grid-connected power generation system, which are generally national-level power stations. Their main feature is that the generated energy is directly transmitted to the power grid, and the power grid is unified to supply power to users. However, this kind of power station has not been developed much because of its large investment, long construction cycle and large area. And the decentralized small grid-connected power generation system, especially the photovoltaic building integrated power generation system, is the mainstream of grid-connected power generation due to the advantages of small investment, fast construction, small footprint, and large policy support.
Distributed power generation system, also known as distributed power generation or distributed energy supply, refers to the configuration of small photovoltaic power generation and power supply system at or near the user site to meet the needs of specific users, support the economic operation of the existing distribution network, or meet the requirements of both aspects at the same time. The basic equipment of the distributed photovoltaic power generation system includes photovoltaic cell modules, photovoltaic square support, DC bus box, DC power distribution cabinet, grid-connected inverter, AC power distribution cabinet and other equipment. In addition, there are power supply system monitoring devices and environmental monitoring devices. Its operation mode is in the solar radiation conditions, photovoltaic power generation system of solar cell module array to convert solar energy output power, a dc bus concentrated into dc power distribution cabinet, by the grid inverter inverter into alternating current supply of building their own load, excess or shortage of electricity through the grid to adjust.