“Did you know The technology used in an inverter also affect its efficiency”
What are DC to AC inverters?
A DC to AC inverter which is normally just called an ‘inverter’ takes the direct current (DC) power produced by a solar panel or wind turbine array and converts it to alternating current (AC) power, which can be supplied around the building to power appliances or fed back into the grid to offset electricity consumption.
Related post: How does a solar panel work?
What are the types of inverters available today?
They are two main variation points to this electrical and electronics device: Either they are constructed with a transformer or not, and they can either produce pure sine wave or modified sine wave.
The Difference between Transformer and transformer-less inverter
A transformer is an electromechanical device inside an inverter which steps up the voltage to 240V or 120V depending on the standard voltage used in your country to power appliances at home.
Though Most inverters sold in some countries today don’t have transformers, and it is observed that some that have no transformers are becoming increasingly popular for a few reasons. the ones with transformers are generally bulky and heavier, and are normally slightly less efficient than the more modern transformerless types that are available in the market today.
Inverter with transformer can also make a fairly loud humming noise, which can be irritating if the device was installed near a living area, but in the case of inverters with no transformer this cannot be seen because it uses electronic circuit in boasting it voltage thus reducing the amount of heat and ˜hum’ generated by the unit, and they are also very much lighter, more compact, and affordable. Though this device can either have a transformer or not but any of the two can be designed to either generate pure sine wave or modified sine wave.
What is the difference between Pure sine wave and modified sine wave inverters?
The difference between a pure sine wave inverter and one which generates a modified sine wave is the type of wave the output current possesses. A ‘pure’ sine wave is simply a smooth wave, whereas a modified sine wave is somewhat like a square wave as shown above.
A pure sine wave inverter will generate almost similar wave produced by the mains power grid from the utility company, which will give a much better efficient energy conversion – a little like the difference between gazing at an extremely high-resolution picture and an extremely low one.
How do the inverters work?
The power that is supplied by the utility company comes in an AC form, which means that the current has an alternating wave coming back and forth, and why the supply this is that, if for any reason you get an electric shock from any of the mains, the AC current is considered to be slightly less likely to kill than the DC current which has a direct signal. So all household appliances are designed to be operated with an AC current, and this is where this device comes in.
In simple terms, the DC electricity generated by a solar or turbine array has no wave to it; it is just a direct flow of current. For it to be utilized, it needs to be the same as the waveform of the AC power coming in from the utility company (a sine wave).
So the electrical and electronic device is designed to use either transistors or an oscillator to switch the voltage back and forth. In some countries the supply current switches at 50Hz, and while other switches at 60Hz, this means the current is switched 50 times a second or 60 times a second.
The better the quality of an inverter, the more closely the waveform is a pure sine wave, and the more efficiently it will regulate power. Lesser quality of this device have the sine wave in steps rather than straight lines (i.e. with a modified sine wave, as mentioned earlier) which can be a bit okay for appliances which do not use much power, but can be a problem for more heavy-duty appliances, especially for anything that has a motor
How are inverters installed?
During installation, it can be placed wherever it is convenient for the householder, though places like the garage, carport, under the staircase, or a special room or corner in the house set aside for power equipment to be installed. The positive (+) and negative (-) of the device is then connected up to both the array, and either the mains power grid or a battery storage system.
If the connection is to be done to the mains that is, if you are staying in countries where solar energy utility grid is supply around the city, you will need a licensed electrician to handle the job. Even if you’re only connecting your inverter to a battery bank, it’s a good idea to contact a licensed installer or electrician to make sure everything works fine.
What to consider when selecting inverter?
There are a few things to look out for when choosing an inverter:
- Standard; If you are staying in a country where there is a utility company supply energy from the solar system grid, your chosen device should meet the company standard.
- Capacity; The one selected should be able to carry the total maximum load designed to be supplied by the inverter and it should be able to cope with maximum power output from the solar panel array if it is connected directly from the array.
- Efficiency; The closer the selected device is to a pure sine wave, the more power you will get from it and the more efficient the inverter
- Warranty. Look out for the warranty of the inverter, a minimum of 5 years is at least good which best manufacturers will even offer a longer warranty.
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