The photovoltaic power generation system consists of a photovoltaic array (a photovoltaic array is composed of photovoltaic modules in series and parallel), a controller, a battery pack, and a DC/AC inverter. The core component of the photovoltaic power generation system is the photovoltaic module, and the photovoltaic module is also composed of photovoltaic cells in series, parallel and packaging. It directly converts the sun's light energy into electricity. The electrical energy generated by photovoltaic modules is direct current. We can use it or convert it to alternating current through an inverter. From one point of view, the electrical energy generated by the photovoltaic system can be used immediately, or it can be stored by energy storage devices such as batteries and released for use at any time as needed.
1. Photovoltaic inverter
In a photovoltaic power generation system, the higher the voltage level, the greater the power and the higher the cost. At present, DC grid-connected inverters are the most used in photovoltaic power generation systems. As one of the core components of the photovoltaic power station, the DC grid-connected inverter is an indispensable equipment in the photovoltaic power generation system and an indispensable part of the power station system. In an inverter, the higher the grid voltage level, the greater the ability of the generated DC power to be converted into electrical energy. Therefore, the inverter not only converts direct current into alternating current, but also converts alternating current into meaningful and stable direct current, so as to connect power generation to the grid and play the role of power generation and grid connection. At present, photovoltaic inverters mainly have three structural forms: three-phase voltage type and three-phase DC type. Among them, the power of the three-phase voltage inverter is generally below 10kW; the power of the three-phase current three-phase voltage inverter is generally above 50kW; the power of the three-phase DC inverter is generally less than 10kW.
2. Battery components
The battery is the core of the photovoltaic system, and it is the component with the longest service life and the longest life of the photovoltaic system. The quality of photovoltaic cells is directly proportional to the cost. Better quality photovoltaic cells cost less, while poor quality photovoltaic cells cost more. Therefore, it is very important to choose the highest quality materials for photovoltaic cells. A good photovoltaic cell must be a good material with high energy density, high power density (high energy density), and low cost (low energy density). Photovoltaic cell components are composed of two parts: 1) photovoltaic modules; 2) photovoltaic cells.
3. Inverter control components
The inverter control part (inverter output terminal and control terminal) consists of input current, output voltage, control signal, reactor and inverter fault detection circuit (inverter power supply part). The output end of the inverter control part mainly includes: output end controller, voltage and current detection controller, inverter protection circuit, energy storage control circuit, etc.; the signal interaction device between the input end and the output end can be a communication interface or Analog communication interface. The inverter control module is mainly responsible for the function of the grid-connected inverter, monitoring, management and control of the photovoltaic power station. The inverter control module adopts PLC control mode.
4. Photovoltaic modules (including: photovoltaic modules)
Photovoltaic modules mainly refer to power devices that use solar radiation to supply power to the system, and are divided into solar photovoltaic modules such as monocrystalline silicon, polycrystalline silicon, and silicon rods. Unlike battery power generation used in inverters, photovoltaic modules are photovoltaic power generation systems composed of cells and components. With its excellent performance and excellent characteristics, solar modules are widely used in various power stations and are the most basic and important components of power stations. Photovoltaic modules are composed of a plurality of glass in series and parallel to form a group of module modules. The module has the advantages of strong absorption of solar radiation, convenient communication with the inverter, and low system operation cost. The power station runs stably for a long time and is environmentally friendly. It has become one of the most important and potential industries for photovoltaic power generation technology. .