What is a solar inverter?

Inverters are a vital part of a solar system. If solar panels are the backbone of a solar power system, the inverter is the brain. Whether it is a 2kW residential system or a 5MW commercial plant, they all require inverters.

As the name suggests, a solar inverter is a component that converts solar energy from direct current (DC) to alternating current (AC), making it usable for home loads. This is because AC is the standard for all commercial appliances. Inverters are therefore considered the bridge between the photovoltaic system and the home's electrical distribution.

What does a solar inverter do?

A solar inverter can be thought of as a translator between two languages, DC and AC. All the electrical wires that run through a home carry or “speak” AC, as do appliances and the electrical grid.

Solar panels, on the other hand, “speak” DC. So we can assume that there is a communication barrier between the two. No solar power system can send power to a home or a power grid without help or “translation.”

The solar inverter is therefore suitable for this job. The main purpose of the inverter is to “ translate ” or ripple the solar energy generated by the user’s solar panels so that their building and electrical grid can use it.

Secondly, the solar inverter has the function of optimizing the production of your solar panels . Indeed, your solar panels have current and voltage characteristics that fluctuate at all times depending on the sunshine, shade, and temperature. The second role of the photovoltaic inverter is to force the panel or string of panels to electrically position itself at the operating point that will produce the most power at all times. This is the maximum power point tracking function, also called MPPT (maximum power point tracking).

In addition to optimizing the operating point and scaling energy from one form to another, inverters mostly serve another important purpose, which is the communication of the solar system with the outside . The solar inverter will allow you to connect your solar energy system to the Internet, and will provide you with information about your system, such as production or operating information.

As the brain of your installation , the inverter is the organ that centralizes information and can organize the energy management of your home . To do this, it needs to be connected to a communicating meter or a gateway that provides it in real time with the value of the current exchanged between your home and the public distribution network. This is particularly useful when you need to compare solar energy production to your home's energy consumption , i.e. the energy reflected on a utility bill.

The different types of solar inverters:

A solar inverter has a high energy efficiency (93 to 98%) and provides alternating current. The type of solar inverter that one chooses depends on the size of the installation and the expected features.

If you want to know more about how a solar system works, don't hesitate to read our article which tells you more!

When it comes to solar energy, there are three types of inverters .

Purely solar inverters.

Pure solar inverters convert the electrical energy from the panels into alternating current. They are connected to a power grid and work by adapting their current to the sine wave of the power grid. They are designed to shut down spontaneously in the event of a power outage for safety reasons. They therefore stop supplying power during a power outage.

String inverters.

String inverters are the most commonly used type of solar inverter by individuals and businesses. The panels are connected in series with each other in strings of 6 to 20 panels depending on the panel voltage and the maximum voltage allowed by the inverter, each string is connected to an input of the string inverter (hence its name). They are of the pure solar or hybrid inverter type. You can find these high-performance inverters with a 10-year warranty on the Oscaro Power website.

String inverters generally allow you to benefit from a broader ecosystem of features (integrated supervision, interfacing features with storage or with a vehicle charging station, control capabilities, etc.), they have better performance and are less expensive in relation to the price in € per Wc of panels installed.

Micro inverters

Micro inverters are smaller in size and power than string inverters. String inverters range from 1.5 to 8.2 kW for residential applications, while micro inverters typically range from 200 to 350 W.

They can be installed at the back of each panel or group of 2 panels and are responsible for the conversion of the panel on which they are installed. They are comparatively a little more expensive, but allow a visualization of the performance of the installation panel by panel. On the other hand, they generally give access to fewer functionalities in terms of storage and control than string inverters.

Battery inverters

Off-grid inverters, also called stand-alone inverters, are those that generate an independent voltage waveform as opposed to grid-tied inverters that sync to an existing grid. Off-grid inverters do not need to be connected to a solar panel. Instead, they draw the necessary DC power from batteries charged using photovoltaic panels or other resources such as engine generators, water turbines, and wind turbines.

Since these inverters are isolated from the power grid, they do not require anti-islanding protection. Off-grid inverters are used in isolated locations or when users want to live completely independently from the grid.

Some of these inverters can operate in connected or isolated mode (example of the Victron Multipus 2) and integrate regulatory anti-islanding protection. They then allow you to optimize self-consumption AND to re-power a secure line in your home in the event of a network failure. Importantly, such a battery inverter allows you to optimize self-consumption and secure it in the event of a network disruption, even on an existing solar installation for which you had not initially planned to add a battery.

Hybrid inverters

This is a partial or total combination of the two types of inverters above, which allows the user to be largely autonomous. That is to say that these inverters have a solar input and a battery input .

In normal operation, they synchronize with the public grid and inject current into this grid. If they are equipped with a battery, hybrid inverters use the solar surplus to first charge the battery. They can then export the excess energy to the grid. At night, in cloudy weather or in cases where production is insufficient to supply the loads, they first use the stored energy for consumption.

Some hybrid inverters allow the loads to be re-powered in the event of a power outage. However, this security feature requires a source inverter at the entrance to the house and the connection to the secure output of the inverter of the power line to be secured within the limit of the power that the inverter or the battery can deliver. This point is a little technical and often requires some electrical work in your general house panel.

Within solar inverters (purely solar or hybrid), we can distinguish 2 technologies for residential applications: a more centralized one, the string inverter, and a more distributed one, the micro inverter.

Increasing your solar self-consumption is easy with Oscaro Power ! To find out more, contact us by email at contact@oscaro-power.com or at 01.75.85.08.88 .