Solar Micro Inverters existed since the advent of the solar PV systems, but then due to high costs associated with manufacturing, it wasn’t popular until recently when a company enphase made the first commercially successful micro inverter M175 in 2008. Since then many established companies like SMA, Power-One (now ABB), Delta and other companies have formally launched these inverters. There are advantages as well as disadvantages of a Micro Inverter over a String or Central Inverters.
- Shade Tolerant: Since each Solar Panel is producing independent of other panels, the performance of a Solar Panel doesn’t affect it’s neighbouring Solar Panel. So a shaded Solar Panel won’t necessarily drop the performance of other solar panels as they work independently. This is not the case with String Inverters.
- No Air-cooling: These are very small inverters that can fit in the back of a solar panel. Because of its size, one doesn’t need to have separate cooling as central inverters. So less loss in the form of heat.
- Minimum Maintainance loss: A defective solar panel or an inverter doesn’t affect the generation of the solar output from other panels, while a defective Solar String or Central Inverter will bring the performance of the entire array to a halt.
- Remote Monitored: Typically in a Micro-Inverter architecture, output from each Solar Panel and the Micro Inverter is monitored via a communication bus, there by isolating a problem much faster than other inverters.
- Smaller Cable Size: Since output is converted from DC to AC (230V) at the back of the panel, the cable required to carry the current can be of lower diameter.
- Easily Expandable: Due to it’s modularity, a solar system can be easily expandable from single panel to multiple panels independent of each other.
- Suitable for Residential Buildings: Due to it’s modularity and it’s size, it’s very suitable for residential buildings where each panel can be differently oriented or have different shading pattern during the day.
- Easy Installation: As there are no specific restrictions on oritenation of solar panels any one can install a micro inverter solar on grid system with relative ease.
- Higher Initial Cost: The main disadvantage of a Micro Inverter is been it’s higher initial cost.But it’s cost can be justified in cases where there are technical challenges in installing a solar array (series of solar panels) or shading issues that could cause the entire system underperform.
- Extra Monitoring Device: As each inverter is independently located below a solar panel, a communication bus and a common monitoring system is required as there is on board display system like in string inverters.
- Higher Cost of Replacing: As a inverter is below the solar panel, it might be very difficult to replace the micro inverter due to existing site conditions and might require more than 1 technician on site to replace.
Microinverters have become common where array sizes are small and maximizing performance from every panel is a concern. Microinverters have been most successful in the residential market, where limited space for panels constrains array size, and shading from nearby trees or other objects is often an issue.