Solar inverters are fundamental devices in a photovoltaic installation, without them we would not be able to use the current generated by the solar panels.
Solar or photovoltaic inverters are components that are responsible for transforming the energy produced in a photovoltaic installation from direct current to alternating current, so that household appliances and other electrical devices can function normally.
Solar or photovoltaic inverters
In other words, it is in charge of converting the energy that is collected by the solar panels (direct current) into electricity to be used in a home or business (alternating current). This process allows us to generate and consume our own electricity.
The main functions of a solar or photovoltaic inverter are:
- Convert continuous electrical energy into alternating , the most demanded type of energy in any home or company. Without this inverter, DC/AC transformers would have to be installed in the electrical equipment.
- It improves the electrical current as it stabilizes the electrical waves and provides a quality and constant supply, thus preventing electrical appliances from suffering.
- It monitors the operation of the photovoltaic installation at all times . Thanks to it we can know if there is something that is not working correctly, notifying us of any problem.
What are they for
The electrical current generated by the photovoltaic panels of our installation is not the usual current that is normally used in the home, nor is it the one that circulates through the conventional electrical distribution network, so a transformation is necessary .
Solar panels produce direct current , while most appliances, electrical devices, and lights use alternating current .
Thanks to the photovoltaic inverter we can transform direct current into alternating current so that in this way we can use it in the home or industry and so that the energy surplus can also be injected into the general electrical network.
How do they work
As we have just commented, the mission of the solar inverter is to convert the direct current produced by the solar panels into alternating current that we can use.
To achieve this transformation, the solar inverter has power electronic devices (transistors, thyristors, coils, capacitors, etc.) through which a linear current is transformed into a sinusoidal current (the one we use in our home or business).
This process generates heat , which is dissipated by the inverter so that the transformation process is efficient. Some inverters have built-in fans for this reason and others dissipate heat by convection.
In addition to their main function, solar inverters are also responsible for:
- Facilitate the supervision of the correct operation of the photovoltaic installation . In the event of a problem, the inverters are able to immediately stop energy production, thus avoiding any risk.
- They offer information on the diagnosis of the equipment to anticipate any possible problem.
- They improve the overall performance of the installation, allowing maximum use of energy from the solar panels.
Types of solar inverters
The classification of inverters varies depending on whether the photovoltaic installation is connected to the grid or isolated:
Grid Tie Inverters
They are the ones that transform the energy generated by the solar panels into electricity , either for the sale of energy or for self-consumption , and therefore have to be synchronized with the general electrical network.
Depending on their technology and their functionalities, there are three types of grid connection inverters :
- String grid connection inverters : This is the most widely used inverter. Each solar panel is connected in series and the energy produced is sent to a single inverter. They are ideal for homes that have a roof that is not affected by shadows and has a single direction. If they have optimizers, they will improve performance in the event that each panel has a different solar production.
These inverters are the cheapest and also offer easy maintenance. Although they are not recommended for installations with many shadows.
- Microinverter is or distributed inverters : Unlike the String, in which there is a single inverter in the entire installation, the microinverters are located in each solar panel individually.
The main advantage they offer is the elimination of the negative impact caused by shadows, since the installation will continue to produce energy even if one or more system boards have lower performance. In addition, they allow individual monitoring of each panel.
- String grid connection inverters with optimizers : The power optimizers are located next to the solar panels or integrated into them individually, although the systems with power optimizers continue to send energy to a centralized inverter.
A solar panel installation with power optimizers is more efficient than one that only uses a string inverter. In addition, the performance of each solar panel can be monitored individually and the effect of shading on the total performance can be reduced. They have lower maintenance costs.
Inverters for isolated photovoltaic installations
They are used in installations without connection to the electrical network , requiring the use of batteries. They are perfect for solar systems in isolated places and without connection to the general electrical network such as boats, country houses, etc. We can divide them into the following categories:
- Isolated : They transform the current from the batteries to 220V to power the electrical appliances. They are programmed to stop supply when the voltage is too low and prevent excessive discharge.
- Inverter-charger: In addition to the inverter for isolated installations, it has a charger that is activated when the battery voltage is very low. By having a charger you can charge the batteries whenever you need.
They are the ones that allow obtaining energy both from the electrical network and from solar batteries. They are perfect for those homes where the electrical network has difficulties.