Solar inverters are one of the primary components of any solar power system. Their job is to convert the direct current (DC) electricity produced by solar panels into alternating current (AC) electricity, the type of electricity used in our homes.
Before we go into details, note that solar inverters are not necessary for certain places; solar panels installed there would work pretty fine without them. For example, they are not required for solar panels on boats, RVs, or any other place where AC electricity is not used.
But how does a solar inverter work, and why is it necessary for home solar panels?
In this article, we’ll explain the ins and outs of solar inverters, how a solar inverter works, and how they enable solar panels to power your home or business. Whether you’re a solar shopper looking to install solar panels or a homeowner looking to better understand how your solar system works, this article makes the working of solar inverters easy and simple.
What is a solar inverter?
Call it an intermediary between your solar panels and your home’s electricity. Without inverters, solar panels can power 12V lights in your lawn but cannot power your entire home.
Here is why.
Grids in most countries around the world use 240V electricity at a frequency of 50Hz. In the United States, the grid and, as a result, all appliances require alternating current at a frequency of 60Hz and voltage of 120V. But the electricity our solar panels produce is in direct current, at 0Hz. That means we would need a device to convert this electricity into usable electricity.
That’s what inverters do—convert the DC into AC. But shouldn’t we call them solar converters instead of inverters? No. Because solar inverters also convert AC to DC for storing purposes and reconvert the stored energy (in batteries) to AC. Hence, the name inverters. Besides converting DC into AC, solar inverters also monitor and optimize the flow of current between solar panels and your home.
Solar inverters are available in the market with at least three types of configurations: string inverters, central inverters, and power optimizer+string inverters. Some work best for homes with no shade, and others are excellent for homes with slight shade on the rooftops. Head to our detailed article on the types of solar inverters and see which one would make more sense for your home.
How does a solar inverter work?
As seen in the image below, DC flows in a straight line, while the AC is in sinusoidal form. Sinusoidal current means the current flows in highs and lows at a rate of 60 cycles per second. To convert this straight line into cycles of highs and lows, inverters use a technique called pulse width modulation (PWM).
PWM enables inverters to chop the DC input voltage into a series of pulses, which are then used to generate the AC output voltage. They switch the DC input voltage on and off very quickly (at a high frequency, 60Hz for the US), creating a series of pulses with varying widths. These pulses are then applied to a transformer, which converts the DC pulses into an AC voltage. By controlling the width of the pulses, the inverter can control the average value of the AC voltage and, thus, the amount of power delivered to the load.
Solar inverter working simplified
Here’s a simplified overview of how solar inverters convert the electricity produced by solar panels:
- Solar panels on the roof of a building absorb sunlight and convert it into DC electricity. This current doesn’t have a frequency and is not fit for use at home.
- The DC electricity is then sent to the solar inverter, which is usually located just beside each solar panel or near the main electrical panel in a building, depending upon which type of inverter you choose.
- The solar inverter converts the DC electricity into AC electricity using pulse width modulation (PWM). The conversion occurs here—the inverter rapidly switches the DC electricity on and off to produce AC electricity at the same frequency as the electricity used in the grid.
- The AC electricity is then sent to your main electrical panel, where it can be used to power lights and appliances
- If the energy is more than you need, the inverter-converted AC will be exported to the grid, provided that you have signed up for a net metering program in your state.
- If your system features a battery bank, the inverters convert the AC again to DC to store it. When the need arises, for example, during a power outage or when the weather turns inclement, it takes the DC back from batteries and converts it into AC electricity.
| Next Earth Solar Fact: The efficiency of an inverter refers to how well it can convert DC power to AC power. Most modern inverters have an efficiency of around 96-98%, which means that they lose a small amount of power during the conversion process. |
Do solar inverters work at night?
No. Solar inverters turn off automatically at night.
As discussed above, solar inverters convert the electricity coming from solar panels to alternating current. But when the sun sets, solar panels stop working. That means there is no input for solar inverters to process. Due to the lack of input, solar inverters automatically turn off at night—some inverters might need to be manually shut down.
If you have a hybrid solar system and there is a blackout, inverters attached to batteries would work at night. It is because the batteries, like solar panels, also provide current in DC form. To be usable, inverters are necessary to convert it into alternating current.
Can I use solar panels without an inverter?
Yes. Solar panels would still generate electricity, but this electricity will not be of much utility to your homes, as our home appliances are designed for alternating current.
However, if solar panels are installed on boats, RVs, or camp, the inverters would not be necessary.
How do solar inverters work? A recap
Solar inverters are essential components of any home solar system, which convert the electricity produced by solar panels into usable electricity. This conversion is the result of a process called pulse width modulation. Other than DC-AC conversion, solar inverters also optimize the solar panels’ performance, serve as the interface with the grid, and ensure safe system operation.
That was all about how does a solar inverter work in simpler terms. If you enjoyed reading this, you may like to read about how solar panels work.