Most household solar energy systems have traditionally used a central inverter within the home to convert DC power from the photovoltaic panels into usable AC current. But that trend is changing as individual solar micro inverters on each PV panel become more common.
Solar panels convert sunlight into direct current (DC) power, but that electricity needs to be converted to alternating current (AC) before it can feed into a home’s wiring (or ultimately into the power grid). The biggest drawback of conventional central inverters (commonly called “string” inverters because each panel in the system is wired together in a continuous string) is that one poorly performing panel will undermine the entire system.
If an individual PV panel in a “string” array malfunctions, or if it simply receives less sunlight because of shade or debris buildup, the entire system produces proportionately less power – sort of like a string of twinkle lights that goes dark when just one bulb fritzes out.
Micro-inverters, on the other hand, convert the DC current to AC power at each individual panel. The electricity from each solar panel then feeds directly into the home’s electrical system through a single main cable. The biggest advantage is maximizing the power output from each panel, plus the ability to easily track the performance of each panel in the system. In addition, any equipment malfunctions can be quickly and easily pinpointed and repaired.
So why don’t all solar arrays utilize micro-inverters? Until recently they added time and cost to the initial installation of a solar energy system. But as more and more manufacturers like Enphase Energy and SolarBridge produce them, prices have dropped significantly – and thanks to the cost savings resulting from better-performing PV panels, micro-inverters will pay for themselves over time. In fact, solar industry giant SunPower recently launched a line of residential solar panels with integrated SolarBridge AC micro-inverters installed during the manufacturing process.
You may also be interested in Modern Enviro’s Home Solar Energy Guide.