Photovoltaic power generation systems are divided into independent photovoltaic systems and grid-connected photovoltaic systems. Independent photovoltaic power stations include village power supply systems in remote areas, solar household power supply systems, communication signal power supplies, cathodic protection, solar street lights and other photovoltaic power generation systems with batteries that can operate independently.
The grid-connected photovoltaic power generation system is a photovoltaic power generation system that is connected to the grid and transmits electricity to the grid. It can be divided into grid-connected power generation systems with and without batteries. The grid-connected power generation system with battery is schedulable and can be integrated into or withdrawn from the power grid according to needs. It also has the function of backup power supply, which can provide emergency power supply when the power grid is cut off for some reason. Photovoltaic grid-connected power generation systems with batteries are often installed in residential buildings; grid-connected power generation systems without batteries do not have the functions of dispatchability and backup power, and are generally installed on larger systems.
System equipment
The photovoltaic power generation system is composed of solar cell arrays, battery packs, charge and discharge controllers, inverters, AC power distribution cabinets, sun tracking control systems and other equipment. Some of its equipment functions are:
PV
When there is light (whether it is sunlight or light generated by other illuminants), the battery absorbs light energy, and the accumulation of opposite-signal charges occurs at both ends of the battery, that is, a "photo-generated voltage" is generated, which is the "photovoltaic effect". Under the action of the photovoltaic effect, the two ends of the solar cell generate electromotive force, which converts light energy into electrical energy, which is an energy conversion device. Solar cells are generally silicon cells, which are divided into three types: monocrystalline silicon solar cells, polycrystalline silicon solar cells and amorphous silicon solar cells.
Battery pack
Its function is to store the electric energy emitted by the solar cell array when it is illuminated and to supply power to the load at any time. The basic requirements for the battery pack used in solar cell power generation are: a. low self-discharge rate; b. long service life; c. strong deep discharge capability; d. high charging efficiency; e. less maintenance or maintenance-free; f. working temperature Wide range; g. low price.
controlling device
It is a device that can automatically prevent the overcharge and overdischarge of the battery. Since the number of cycles of charge and discharge and the depth of discharge of the battery are important factors in determining the service life of the battery, a charge and discharge controller that can control the overcharge or overdischarge of the battery pack is an essential device.
Inverter
A device that converts direct current to alternating current. Since solar cells and batteries are DC power sources, and the load is an AC load, an inverter is essential. According to the operation mode, inverters can be divided into independent operation inverters and grid-connected inverters. Stand-alone inverters are used in stand-alone solar cell power systems to power stand-alone loads. Grid-connected inverters are used for grid-connected solar cell power generation systems. The inverter can be divided into square wave inverter and sine wave inverter according to the output waveform. The square wave inverter has a simple circuit and low cost, but has a large harmonic component. It is generally used in systems below several hundred watts and with low harmonic requirements. Sine wave inverters are expensive, but can be applied to various loads.
tracking system
Compared with a solar photovoltaic power generation system at a fixed location, the sun rises and sets every day in four seasons of the year, and the sun's illumination angle changes all the time. If the solar panel can always face the sun, the power generation efficiency will be improved. reach the best condition. The sun tracking control systems commonly used in the world all need to calculate the angle of the sun at different times of each day of the year according to the latitude and longitude of the placement point, and store the sun position at each time of the year in the PLC, single-chip computer or computer software. , that is, by calculating the position of the sun to achieve tracking. The computer data theory is used, which requires the data and settings of the latitude and longitude regions of the earth. Once installed, it is inconvenient to move or disassemble. After each move, the data must be reset and various parameters must be adjusted; principle, circuit, technology, equipment Complicated, non-professionals cannot operate it casually. A solar photovoltaic power generation company in Hebei has exclusively developed an intelligent sun tracking system that is world-leading, low-cost, easy to use, does not need to calculate the sun's position data in various places, has no software, and can accurately track the sun on mobile devices anytime, anywhere. The system is the first solar space positioning tracker in China that does not use computer software at all. It has an international leading level and is not limited by geographical and external conditions. It can be used normally within the ambient temperature range of -50°C to 70°C; the tracking accuracy can be Reach ±0.001°, maximize the sun tracking accuracy, perfectly realize timely tracking, and maximize the utilization of solar energy. It can be widely used in places where various types of equipment need to use sun tracking. The automatic sun tracker is affordable, stable in performance, reasonable in structure, accurate in tracking, and convenient and easy to use. Install the solar power generation system equipped with the smart sun tracker on high-speed cars, trains, communication emergency vehicles, special military vehicles, warships or ships, no matter where the system goes, how to turn around, turn around, smart sun tracker All can ensure that the required tracking part of the device is facing the sun!
How it worksEdit Broadcast
Photovoltaic power generation is a technology that directly converts light energy into electrical energy by utilizing the photovoltaic effect of the semiconductor interface. The key element of this technology is the solar cell. After the solar cells are connected in series, they can be packaged and protected to form a large-area solar cell module, and then combined with power controllers and other components to form a photovoltaic power generation device.
The solar photovoltaic module converts direct sunlight into direct current, and the photovoltaic strings are connected in parallel to the DC power distribution cabinet through the DC combiner box. into the AC power distribution cabinet, and directly into the user side through the AC power distribution cabinet.
The efficiency of domestic crystalline silicon cells is about 10 to 13% (should be about 14% to 17%), and the efficiency of similar foreign products is about 12 to 14%. A solar panel consisting of one or more solar cells is called a photovoltaic module. Photovoltaic power generation products are mainly used in three aspects: first, to provide power for powerless occasions, mainly to provide power for the living and production of residents in the vast powerless areas, as well as microwave relay power supply, communication power supply, etc. In addition, it also includes some mobile power supplies and Backup power supply; second, solar daily electronic products, such as various solar chargers, solar street lights and solar lawn lights; third, grid-connected power generation, which has been widely implemented in developed countries. my country's grid-connected power generation has not yet started, however, part of the electricity used for the 2008 Beijing Olympics will be provided by solar power and wind power.
In theory, photovoltaic power generation technology can be used in any occasion that requires power, ranging from spacecraft, down to household power, as large as megawatt power stations, as small as toys, photovoltaic power sources are everywhere. The most basic components of solar photovoltaic power generation are solar cells (sheets), including monocrystalline silicon, polycrystalline silicon, amorphous silicon and thin film cells. Among them, monocrystalline and polycrystalline batteries are used the most, and amorphous batteries are used in some small systems and auxiliary power sources for calculators. The efficiency of China's domestic crystalline silicon cells is about 10 to 13%, and the efficiency of similar products in the world is about 12 to 14%. A solar panel consisting of one or more solar cells is called a photovoltaic module.
Post time: Sep-17-2022