The grid-connected PV system can convert the DC power output by the solar cell array into AC power with the same amplitude, frequency, and phase as the grid voltage, and realize the connection with the grid and the transmission of electric energy to the grid. The flexibility of this kind of power generation system is that when the illumination is strong, the photovoltaic power generation system supplies the AC load while sending the excess power into the grid; when the illumination is insufficient, the solar modules cannot provide enough power for the load. It can also obtain electrical energy from the grid to supply power to the load.
Grid connected photovoltaic power generation system is a new investment model that can be used by itself and the surplus power can be sold into the State Grid to obtain income. It can be installed in areas with sufficient light and no shelter. It is suitable for residential roofs, industry and commerce, medium and large ground stations. The system is mainly composed of photovoltaic modules, inverters, grid connected cabinets, metering meters, etc., with power ranging from 3-1000KW.
At the day, in illumination conditions, the solar cell modules generate a certain electromotive force, and the solar cell array is formed through the series and parallel connection of the modules so that the voltage of the array can meet the requirements of the input voltage of the system. According to whether it relies on the public grid, it is divided into off-grid and grid-connected. The off-grid system operates independently and does not need to rely on the grid. The off-grid photovoltaic system is equipped with a battery with energy storage function, which can ensure the stability of the system power and can supply electricity to the load when the photovoltaic system does not generate power at night or when the power generation is insufficient on cloudy and rainy days.
Regardless of the form, the working principle is that photovoltaic modules convert light energy into direct current, which is transformed into alternating current under the action of the inverter, and finally realizes the function of electricity consumption and Internet access.
Solar energy, a clean and renewable natural energy, is used to generate electricity without consuming non-renewable and carbon-containing fossil energy with limited resources, without emissions of greenhouse gases and pollutants, in harmony with the ecological environment, and in line with the strategy of sustainable economic and social development.
The generated energy is fed into the grid, and the grid is used as the energy storage device to save the battery. Compared with the independent solar photovoltaic system, the construction investment can be reduced by 35% to 45%, so that the cost of power generation is greatly reduced. The secondary contamination of the battery is avoided by eliminating the battery, and the mean time free from failure of the system is improved.
The perfect combination of photovoltaic cell modules and buildings can not only generate electricity but also serve as building materials and decoration materials so that the full use of material resources can play a variety of functions, which is not only conducive to reducing construction costs but also improve the building's scientific and technological content and increase selling points.