According to the needs of different application scenarios, photovoltaic power generation systems can be divided into five types: photovoltaic grid-connected systems, photovoltaic grid-connected energy storage systems, photovoltaic off-grid energy storage systems, grid-connected and off-grid energy storage systems, and photovoltaic storage micro grid systems.
1. Photovoltaic grid-connected system
Working logic: The direct current generated by the solar panel is converted into alternating current by the inverter and sent to the grid.
Application scenarios: large ground power stations, medium-sized industrial and commercial power stations, and small household power stations.
Advantages: No need to use batteries, which saves costs; from an investment point of view, excess electricity can be sold to power companies for profit.
2. Photovoltaic grid-connected energy storage system
Working logic: When the solar power is greater than the load power, part of the solar energy is converted into AC power to supply power to the load through the inverter, and the remaining inverter will store the power in the battery; when the solar power cannot meet the load needs, the inverter will The electric energy stored in the battery is converted to supply the load to ensure the continuity and stability of the entire system.
Application scenarios: It is used in applications such as photovoltaic self-consumption, which cannot be connected to the Internet, the price of self-use electricity is higher than the price of on-grid electricity, and the peak electricity price is more expensive than the flat electricity price.
Advantages: When the light is strong during the day and the power consumption is not high, the excess power generation can be stored to increase the proportion of spontaneous self-use.
3. Photovoltaic off-grid energy storage system
Working logic: It operates independently without relying on the power grid. When there is light, it converts DC power into household AC power, supplies power to the load, and charges the battery pack at the same time; when there is no light, the battery supplies power to the AC load through the inverter.
Application scenarios: Widely used in remote mountainous areas, non-power areas, islands, communication base stations and street lamps, etc., mainly in areas without power grids or areas with frequent power outages.
Advantages: It is not restricted by regions, does not depend on the power grid, and has a wide range of use. As long as there is sunshine, the photovoltaic off-grid energy storage system can be installed and used.
4. Photovoltaic and off-grid energy storage system
Working logic: The photovoltaic array converts solar energy into electrical energy under the condition of illumination, supplies power to the load through the integrated machine, and charges the battery pack at the same time. load power supply. When the power grid is out of power, it switches to the off-grid state, supplies power to important loads through the backup mode, and switches back to grid-connected work when the power grid recovers.
Application scenario: It is mainly suitable for applications where the power grid is unstable and has important loads, or the photovoltaic self-consumption cannot be connected to the Internet, the self-use electricity price is much more expensive than the on-grid electricity price, and the peak electricity price is much more expensive than the wave level electricity price.
Advantages: The battery can be used to store the electricity converted by the photovoltaic array, and the proportion of self-generated and self-consumption can be increased. It can also be used to charge the battery during off-peak hours and use it during peak electricity consumption to reduce electricity expenses. For off-grid operation, use as a backup power source.
5. Photovoltaic micro grid energy storage system
Working logic: It can be connected to the external grid or run in isolation. The photovoltaic array converts solar energy into electrical energy in the presence of light, supplies power to the load through the inverter, and charges the battery pack through the PCS energy storage converter; when there is no light, the battery passes through the PCS energy storage converter. supply power to the load.
Application scenario: It is suitable for the establishment of small and medium-sized distributed power sources in islands and remote mountainous areas where people live more.
Advantages: including all applications of off-grid systems and grid-connected systems, there are multiple working modes, maximize the use of photovoltaic power, and reduce the user's dependence on the grid. It can fully and effectively exert the potential of distributed clean energy, reduce the unfavorable factors such as unstable power generation and low reliability of independent power supply, and ensure the safe operation of the power grid. The micro-grid system can promote the upgrading of traditional industries. huge effect.
Summary: Various types of photovoltaic power generation systems have their own advantages and disadvantages, and it is necessary to choose the type of system reasonably to match user needs and realize customer value. At present, the photovoltaic grid-connected system is the most important form. It does not require batteries and has low system cost. It is the first choice for investment. However, it is believed that with the reduction of the cost of energy storage batteries, the application of various photovoltaic energy storage systems will become more and more extensive.