Solar InvertersSolar photovoltaic inverters, or power inverters, are a fundamental element in any photovoltaic installation. We are going to see in detail the fundamental aspects that you should know about this device, from its operation to the different What is a photovoltaic inverter and how does it work?
A solar inverter is responsible for transforming the energy produced by a photovoltaic equipment (the well-known solar panels) and convert it into an alternating current for the different electronic equipment of a home, while the rest of the appliances that are not connected to this type of current will work as it normally does without being affected.
This means that in the home there will be two options, the direct current produced by the photovoltaic installation and the electricity or alternating current that is always used in the home. In Spain most of the inverters installed are connected to the grid.
Types of solar inverterTo know how photovoltaic inverters are classified, we must first distinguish between two large groups:
Isolated connection inverter.
This type of inverter is used in an off-grid solar installation, i.e. it is not connected to the grid and is used, for example, for self-consumption.
Firstly, depending on the output provided by the inverter, we have single-phase and three-phase inverters:
- The single-phase inverter are known for connecting to a grid directly. They provide the electricity normally found in homes, powering appliances or lighting and have low electricity loads.
- The three-phase inverter consists of three thin connections that constantly carry power. This type of connection is not common in homes, but can have applications for, for example, motors or some types of lighting.
Moreover, we can distinguish according to the quality of the generated wave between:
Those of Modified sine wave, whose wave is square and is not recommended for high loads with sensitive electronics. They can be used, for example, to charge a cell phone, watch TV, lighting or radio.
Pure sine wave inverters. This type of inverter is the most suitable for the electrical installation of a home. It is the one that best suits the proper functioning of household appliances at home, as they need a quality alternating current. For example, any device with a motor such as a washing machine, refrigerator, power tools or others such as a microwave.
We should also mention the type of DC input of the inverter, which can be 12, 24 or 48 volts DC.
Inverter for grid-connected systems
Another classification of power inverters is for grid-connected systems. Within this type, we distinguish between centralized inverters, string inverters, micro inverters and power optimizers:
- The centralized inverter is the one that covers most of the photovoltaic field. In other words, it concentrates several strings (each consisting of its corresponding photovoltaic panels) in a single inverter. Despite this advantage of concentration, in case of failure of the inverter, a large part of the production of the installation will be lost, or even all of it, if only one inverter is installed. It is a type of industrial inverter used in large photovoltaic plants.
- String inverters are connected consecutively in each of the strings, sending the energy to the same point afterwards. It is one of the most economical ways of all those on the market and its maintenance is extremely simple.
- On the other hand, the microinverter is considered a distributor type because, unlike the previous one, the energy will be sent individually from each of the modules. A point in favor is that if one of the panels does not work, the system continues to generate energy, while in the string inverter they all generate at the same rate.
- The power optimizer is a middle ground between the micro inverter and the string inverter and is just as individual in the installation as the micro inverter. Each solar panel operates separately but despite their individuality they send the inverter to the same point as the string inverter. One of the advantages of choosing an optimizer is its individual installation, making it easier to work with and at the same time very economical to maintain. Like the string inverter, it is one of the best options both in terms of installation and in terms of the money you will save in maintenance.