Inverters are designed to convert DC to AC
What Is PV Inverter
Photovoltaic inverter (PV inverter / solar inverter) can convert the variable direct current generated by photovoltaic (PV) solar panels into alternating current (AC) of commercial frequency, which can be fed back to the commercial power transmission system or supplied off-grid grid usage. Photovoltaic inverter is one of the important balance of system (BOS) in photovoltaic array system, which can be used with general AC power supply equipment. Solar inverters have special functions for photovoltaic arrays, such as maximum power point tracking and islanding protection.
Photovoltaic Array
Photovoltaic Array connection of multiple photovoltaic modules,
It is also the connection of more photovoltaic cells, the photovoltaic array is the largest scale of photovoltaic power generation system
PV Array And Inverter Matching
✧Three aspects: voltage matching, current matching and power matching.
◆The maximum number of series modules designed for the photovoltaic array should ensure that the array output voltage does not exceed the maximum open circuit voltage.
The maximum allowable input voltage of the PV inverter.
✧For the current, it should be ensured that the output current of the array is not greater than the maximum input current of the inverter.
✧ On the premise of conforming to the voltage range and current range, adjust the number of series components of the photovoltaic array so that the array
The output is close to the rated power of the inverter in order to obtain the highest inverter efficiency.
01. Grid-connected system – grid-connected energy storage system
02. Off-grid system-off-grid energy storage system
03. On-grid and off-grid system-on-grid and off-grid energy storage system
Grid-Connected System
- Main components: solar modules, grid-connected inverters, loads and grids
- 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, saving costs; from an investment point of view, excess electricity can be sold to power companies for profit
Grid-Connected Energy Storage System
- Main components: solar modules, batteries, grid-connected energy storage inverters, loads and grids.
- 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 electrical energy 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 grid, 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.
Island Effect
The islanding effect means that when the grid connected to the photovoltaic power generation system is tripped due to a fault, accident or power outage maintenance, the photovoltaic grid-connected power generation system at the user end fails to detect the power failure state of the power grid in time, and does not quickly disconnect the photovoltaic power generation system from the parallel grid. , still feeding electricity to the public grid, thus forming a self-sufficient power supply island formed by the photovoltaic power generation system and the surrounding loads.
Off-Grid Energy Storage System
- Main components: solar modules, off-grid inverters, batteries, loads and grid
- 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-electric 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.
On-Grid And Off-Grid System
- Main components: solar modules, Hybrid Inverter, batteries, off-grid loads, grid-connected loads and grids
- 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 unstable power grid and important load, or photovoltaic self-consumption cannot be connected to the Internet, and the price of self-use electricity is more expensive than the price of on-grid electricity.
- 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.
Maximum Power Point Tracking
Maximum power point tracking (MPPT) is a technology commonly used in wind turbines and photovoltaic solar systems, with the purpose of obtaining the maximum power output in various situations.
Microgrid 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 under the condition 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, with multiple working modes, maximizing the use of photovoltaic power, and reducing 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.