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The solar AC power generation system is composed of solar panels, charge controllers, inverters, and batteries; the solar DC power generation system does not include inverters. The process of converting AC power into DC power is called rectification, the circuit that completes the rectification function is called a rectifier circuit, and the device that realizes the rectification process is called a rectifier or rectifier.
Correspondingly, the process of converting DC power into AC power is called an inverter, the circuit that completes the inverter function is called an inverter circuit, and the device that realizes the inverter process is called inverter equipment or inverter.
The core of the inverter device is the inverter switch circuit, referred to as the inverter circuit. The circuit completes the inverter function by turning on and off the power electronic switch. The on-off of power electronic switching devices requires certain driving pulses, which may be adjusted by changing a voltage signal.
Circuits that generate and condition pulses are often called control circuits or control loops. The basic structure of the inverter device, in addition to the above inverter circuit and control circuit, includes the protection circuit, output circuit, input circuit, and so on.
A solar inverter is a device that converts the direct current in a solar battery into alternating current. Inverters, also known as power regulators and power regulators, are an essential part of photovoltaic power generation systems. The working circuit of the solar inverter must be a full-bridge circuit. Through a series of filtering and modulation in the full-bridge circuit, the load and electrical properties of the current are changed to achieve the user’s expected purpose.
A common solar power generation system is mainly composed of four parts, namely solar panels, charge controllers, solar inverters, and batteries.
The solar panel is a device that provides direct current, which can convert solar energy into electrical energy; the charge controller is mainly responsible for controlling the conversion of energy; the solar inverter converts the direct current of the panel into alternating current for storage of the battery, and the battery is mainly used to convert The alternating current is stored for human use.
Solar inverters play a connecting role in the entire solar power generation system.
The main features of solar inverters are centralized inverters and string inverters. The scale of solar power generation systems is generally very large. If one solar panel corresponds to one inverter, it will cause a waste of resources, which is very impractical.
Therefore, in actual production, solar inverters perform centralized inversion of the direct current generated by all panels and convert it into alternating current.
Therefore, the scale of the solar inverter generally needs to adapt to the scale of the battery panel. Therefore, a single solar inverter obviously cannot meet this requirement, which leads to another feature of the solar inverter, which is often used in strings.
The inverter not only has the function of DC-AC conversion but also has the function of maximizing the performance of solar cells and the function of system fault protection.
In summary, there are automatic operation and shutdown functions, maximum power tracking control function, independent operation prevention function (for the grid-connected system), automatic voltage adjustment function (for the grid-connected system), DC detection function (for the grid-connected system), DC grounding Detection function (for the grid-connected system).
Here is a brief introduction to the functions of automatic operation and shutdown and the function of maximum power tracking control.
1. Automatic operation and shutdown function: After sunrise in the morning, the solar radiation intensity gradually increases, and the output of the solar battery also increases. When the output power required by the inverter is reached, the inverter will automatically start running.
After starting to run, the inverter will monitor the output of the solar cell components all the time, as long as the output power of the solar cell components is greater than the output power required by the inverter, the inverter will continue to run; until the sunset stops, even if The inverter can also operate on rainy days.
When the output of the solar cell module becomes smaller and the output of the inverter is close to 0, the inverter will form a standby state.
2. Highest power tracking control function: The output of the solar cell module changes with the intensity of solar radiation and the temperature of the solar cell module itself (chip temperature). In addition, because the solar cell module has the characteristic that the voltage decreases with the increase of the current, so there is an optimal working point that can obtain the maximum power.
The intensity of solar radiation is changing, and obviously, the best working point is also changing. In relation to these changes, the operating point of the solar cell module is always at the maximum power point, and the system always obtains the maximum power output from the solar cell component. This kind of control is the maximum power tracking control.
The most important feature of the inverter used in the solar power generation system is to include the function of maximum power point tracking (MPPT).
Written by: FUJIREJA NEW ENERGY GROUP
The Exporter and Manufacturer of Solar Energy Storage, Inverters
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