The Solar Module Inverter

2017.01.25

Explaining how module inverters work and why you should, or shouldn't chose them.

The solar module inverter is the second most vital component of any solar system, behind only the panel itself. Its role is to change the direct current (DC) produced by the panel into alternating current (AC) electricity that is needed by the electricity grid and used by domestic electrical appliances. Inverter technology has progressed over the last few years and now inverters perform a number of additional tasks alongside simply inverting the current. These include system monitoring and control functions, which keep the solar system working to its maximum efficiency. They also allow technicians to carry out diagnostics on the system. By undertaking these complex tasks, the module inverter is really operating as the electronic brain of the solar PV system. There are a number of competing systems to pick from and choosing which is best for any one installation is one of the most vital decisions to be made. Basically there are three types of system: the micro-inverter, string inverters, and central inverters. Each has its own pros and cons, so it is important to have an understanding of the features of each type of system.


Comparing String, Central, and Micro-Inverters

Solar PV panels are installed in rows, also known as strings. A domestic roof, for example, may have 12 panels installed in three rows of four, or three strings. These strings all connect to the string inverter, sometimes many on large systems, which converts the DC power produced by the panels into usable AC power. The technology behind string inverters has been used for a long time and is well understood. This is a sensible choice for systems that do not suffer from being in shade and where all the panels face the same direction. This is due to the fact that the string inverter manages all of the panels together, so that if one is shaded and producing less power, the production of each panel in the PV system is reduced to match that of the shaded panel. Despite this drawback, the technology of string inverters is proven in countless solar PV installations and it is cheaper than other technologies. Central inverters work just like string inverters; the difference is that they are larger and can work with a greater number of strings. They perform well in big installations where production is usually reasonably constant. The micro-inverter is becoming more common as the price of the technology decreases and they become more affordable. The micro-inverter operates by doing the DC to AC conversion at the module level. This is an important benefit, because it allows the production of each panel to be individually managed. If one panel is shaded, the others will not need to have their production reduced to correspond. This makes them an ideal choice for systems that are shaded and where panels are facing different directions. Some manufacturers now build micro-inverters directly into PV panels, which can make them cheaper and quicker to install.


Buying the Correct Module Inverter

Choosing the right module inverter for any system requires careful consideration of the individual site, looking for potential shading issues, different panel aspects, and the likelihood of steady production. The available budget and size of the installation are also factors to be taken into consideration. Whether sourcing string, central, or micro-inverters, Solarodo offers a marketplace to make sure customers get the most appropriate technology at the right price. A comprehensive selection of solar panels, components, technologies, and supporting infrastructure gives people everything they need for a successful system installation. The marketplace offers both new and used equipment, so it is much easier to source compatible modules for existing installations, should they need to be replaced or extended.