Alternative Home Energy

Solar Inverters for Home & Residental Electricity

As your home-generated solar energy leaves the PV panels and is directed into the house, the DC current must first be converted to AC current before it can be used. This is accomplished through the use of a device called a solar inverter.

DC to AC Solar Inverter

The standard solar inverter works no differently than any other inverting device you may have already experienced. Most commonly known are inverters that provide a cable to plug into a car's power jack, with the other end of the cable ending in an inverter box. The box then contains two or three-prong outlets so that common AC appliances, radios, or other electrical devices can be plugged in. This allows them to run off the direct current produced by the car's battery, even though those devices require alternating current.

Solar inverters can come in many sizes. Larger, digitally programmable models are available for bigger home solar panel arrays, but smaller inverters are also sold to handle the requirements of smaller scale systems or portable solar equipment. Grid-tie solar inverters are sold for any home photovoltaic solar energy system that may be tied into the local utilty company's power grid. These operate exactly the same as any other solar inverter with the exception of an additional phasing process that makes sure the electrical current being fed back to the electric company is in phase with the rest of the power in the grid.

Solar Inverters - Interacting with Home PV Panel Charge Controllers & Solar Batteries

For solar-powered homes not taking advantage of net-metering via a grid-tie electrical system, the DC current being fed from the photovoltaic panels can be run directly from the charge contoller into the solar inverter. The same goes for the solar battery - current can be fed directly into the inverter, without regard for matching specific current frequency requirements of an outside power grid source. Inverters used for this purpose are known as 'stand-alone' solar inverters.

In the case of grid-tied solar power systems, the inverter must work not only to regulate the current but to modify its frequency to match that of the power grid. The power company provides the specific sine wave measurement of the current it's using to send residential electricity - and inside the solar inverter an oscillator modifies the DC signal to match that sine wave. Once the electrical wave is synched up with that of the power grid, the solar-generated electricity flows out of the home and into the power grid to be used by neighboring residences. This happens only when your solar PV panels are generating more electricity than your home is using. During this time however, your electric meter will actually spin backwards, adding money to pocket in the form of reduced monthly electric bills!

Maximum Power Point Tracking Increases Solar Output

When choosing a solar inverter, be sure to find a model that includes a feature known as Maximum Power Point Tracking (MPPT). These inverters make optimum use of solar-generated current by working to get the maximum amount of power it can possibly get from the PV solar array. Each array will have a different maximum power point output depending upon its size and the amount of sunlight it may be receiving at any given time. An inverter with MPPT will track this maximum output figure and work to produce power equal to that voltage when converting the DC to AC current.

Solar inverters can be installed just about anywhere convenient to the rest of the home PV power system. Many are wall-mounted so that they're conveniently out of the way. Once installed, these devices pretty much run themselves. They require little to no maintenance, and as with the case of any home solar equipment should just be checked up on from time to time.

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