What is a Solar Micro-inverter?

A solar inverter is a vital element in any solar energy system, this unit will convert direct current or DC generated from the solar panel, into alternating current or AC. This is necessary, as usable AC power is required to run the appliances in most homes. In the past the traditional inverter was the only unit available for this task. However, less than a decade ago, the solar micro-inverter began to be used to provide AC power for some domestic and industrial installations. Although the technology was very popular with both customers and installers, as with any new technology, the early adopters paid a higher price for innovation. Now, the latest solar micro-inverters have become a cheaper and more attractive alternative to the traditional “string” inverter.
Probably, the first thing to understand is that while solar micro-inverters have come a long way recently. In many ways, engineers have only scratched the surface of their full potential. They have many advantages over the more primitive “string” inverters, which by comparison are less efficient and clumsy in operation. Solar micro-inverters are also smaller, easier to install, cheaper to build (and thus purchase), more flexible in use and safer.
For many people, especially homeowners, the main area of interest will be in regard to the solar micro-inverters increased efficiency. This is understandable, as any gains in this area, will make the payback time on an investment in a solar energy system shorter. In a typical installation the solar panels are connected into an array, a “string” inverter has the panels wired in series, if a single panel in the array is adversely effected, the entire system is compromised. These adverse effects include manufacturing defects, debris on the panel and shading. If a single solar panel has a 9% loss in efficiency, the whole system could have a 54% performance loss. In contrast, the solar micro-inverter is wired to the solar panels in parallel, in the above example, the system would only suffer a 9% efficiency loss on the single affected panel, the other panels in the array would function normally.
Although the way solar micro-inverters are wired plays a large part in their increased efficiency, this is not the only advantage they have. They also use a technique known as “Maximum Power Point Tracking” or “MPPT” to get the most out of photo-voltaic cells. This system samples the output of connected solar cells, and based on the readings taken, the system applies the optimal resistance. This ensures that the maximum power output, for the current environmental conditions is achieved. Additionally there are new CIGS modules that are beginning to become available. These new solar panels are thin-film, they are thinner, lighter and provide a higher energy yield in relation to their surface area. The flexible nature of micro-inverters, make them ideal to get the very most out of these new solar panels.
Another fairly recent development is the introduction of dual micro-inverters. These units can accept DC input from two modules at once. In time, this will lower production costs and reduce the amount of space required to accommodate the units. Industry insiders claim, that the dual unit will lower the price of a micro-inverter to less than the cost of a traditional “string” inverter. As cost was one of the main reasons that micro-inverters have not been widely adopted, it’s safe to say that the removal of this final barrier, will make them an attractive choice.
The future development of even more efficient micro-inverters, will make them a vital part of any solar energy system. Cloud based monitoring of modules, with ready access to real time performance data and remote troubleshooting, will become standard practice. This will enhance the experience for the user and speed up the payment time on the initial investment. All these factors will make the solar micro-inverter the sensible choice for both domestic and industrial applications for many years to come.

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