More AC Power from Solar Panels

There's more to solar power than blue glassy panels shimmering on rooftops. Just as important are the inverters that convert DC power created by the solar panels into grid-ready AC power. Typically, all the panels in a rooftop PV system are connected to one large inverter mounted on the side of a house.

Behind the scene: Small micro-inverters, such as the one shown above, can be attached behind each solar panel to convert DC power into AC and improve the system’s overall efficiency. Credit: Enphase Energy

Startup Enphase Energy of Petaluma, CA, is now making the first micro-inverters. These smaller inverters can be bolted to the racking under each solar panel, to convert DC power into AC for each panel individually. The company claims that the devices will increase a PV system's efficiency by 5 to 25 percent and decrease the cost of solar power.

Enphase has raised more than $20 million in its latest round of funding. The company has teamed up with various distributors and partners, including solar-module manufacturer Suntech Power Holdings and installerAkeena Solar, to bring its device to customers. The micro-inverters could be used on residential, commercial, or even utility-scale PV systems, says Todd Wilson, a general partner at RockPort Capital Partners, one of the leading investors in Enphase's technology.

In addition to DC-to-AC conversion, inverters are in charge of getting the most power from solar modules. They have a logic circuit that constantly searches for the best voltage and current levels at which the panels can operate. (Power is the product of voltage and current.link..