If you're new to solar energy, or even if you've been involved with it for some time, some things may leave you scratching your head, and asking such things as, "How do Solar Inverters Work?".
Well, no more head scratching - let's look at just how an inverter works.
Why Do You Need An Inverter?
Solar panels produce DC (direct current) electricity. DC electricity is created by electrons moving in one direction from negative to positive. It's mainly used in basic applications involving the use of a battery such as a flashlight and is good for use over short distances.
Most household appliances and electronic devices run off AC (alternating current) electricity. AC electricity is created by electrons moving back and forth between negative and positive terminals, producing a sine wave. The advantage of AC electricity is that the voltage can be adjusted, making it easier to move over longer distances, which is why it's used in households.
Since solar panels only produce DC electricity, an inverter is used to convert the DC into usable AC electricity.
Inverters' Waves Are Different
Inverters convert DC into AC electricity in steps to produce various wave forms. A basic inverter produces a square wave, but only a small voltage, so these are only used to run small appliances and light bulbs. If all you want is to run your coffee maker, this should do fine.
Some more sophisticated inverters use more steps to produce a modified square wave, or modified sine wave as they're more commonly known, which is fine for motors, televisions and lights and large power surges, but may cause problems with more sensitive electronics and devices. These inverters also produce harmonic distortion, resulting in background hum in audio equipment.
The most sophisticated - and, therefore, most expensive - inverters use the most steps to produce a true or near true sine wave, and, as a result, are the type most found in residential PV systems. As more sensitive electronics such as computers were introduced into homes, these became standard for residences.
The Various Applications Of Inverters
In off-grid applications, DC electricity is stored in batteries. An inverter then converts the electricity from the batteries into usable AC electricity. The inverter must be large enough to power all the appliances and devices that will be running at the same time, and must be able to handle surges of power from clothes and dish washers, dryers, etc.
Grid-tied inverters supply power to the home when needed, feeding any excess power into the grid. They include sophisticated detection equipment which ensures they shut down when a grid outage is detected or when utility workers need to work on the grid.
Grid-tied inverters with battery backup work the same as grid-tied inverters as long as the grid is up, but, if an outage should occur, they'll switch the home's power supply to feed off the batteries. When the grid comes back on, the inverter switches back to using the grid, while recharging the batteries.
As you can see, an inverter is essential if any or all your electricity comes from solar panels. Advances in inverter technology are being made all the time, with the main drawback being the lack of efficiency, since most inverters operate at only 90-95% efficiency.
Knowing the internal workings of an inverter is not vital, but selecting the right inverter for a particular application is, so consulting a solar professional or company on the right inverter to buy is extremely advisable.
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