Solar Inverter

In the case of inverters, the old adage is true: you get what you pay for.

Note that the effectiveness of modified sine wave inverters (also known as quasi-sine wave inverters and modified square wave inverters) can vary between different inverters and can vary depending on the load. The least effective modified sine wave inverters are only useful for very basic appliances like toasters and appliances that use only a heating element.

A modified sine wave, on the other hand, rises up to the positive point and down to the negative point in steps it looks like a stepped square wave. While many appliances will run on this type of sine wave, they may not run as well while computers and TVs will run, certain bread makers, microwaves, washer and dryers, etc. may have problems with the modified sine wave. Also, items with motors will end up using more power when using a modified sine wave versus a true sine wave.

The alternating current used by a city electric grid is a true sine wave. It runs smoothly up and down in an arced, wave-like motion. Of course, an inverter that produces a pure sine wave often costs more than other inverters only higher quality solar inverters produce true sine waves.

The DC electricity produced in the PV cells does not have a wave form, but is rather a direct line (hence its name, direct current). Basically, to become AC, it must become a sine wave (on an x-y graph, the sine wave rises from 0 to a positive point, then back down through zero to a negative point and back up to 0. This known as one cycle or a hertz a regular sine wave has 60 hertz per second [the sine wave continues to repeat itself 60 cycles per second])

Sine Waves

For regular consumer use, and alternating current (AC) is needed 120 volt AC powered home appliances require AC electricity. This is where an inverter comes in. The inverter takes the direct current and (note: this is a very simplified explanation) runs it through a transformer. It is almost as though the inverter is tricking the transformer into thinking it is getting AC by forcing the DC to act in a way similar to AC the inverter runs the DC through two or more transistors that are rapidly turned on and off and feeding two different sides of the transformer.

The semiconductor layers are a combination of both positive and negative layers, and they are connected through a junction. Basically, as the sun shines down, the semiconductor material absorbs the light, transferring the lights energy to the PV cell. This energy knocks electrons loose, and they move from one layer to the other, thereby producing an electric current. This is a direct current (DC). The energy created is then generally either stored in a battery bank for later use or sent directly to an inverter, depending on the set up and type of system.

To explain how solar inverters work, you must start from the beginning. The sun shines down onto photovoltaic (PV) cells. These cells are made of semiconductor layers of crystalline silicon or gallium arsenide, and they are arranged into panels.

How Solar Inverters Work

Alternating current, on the other hand, reverses direction and has a varying magnitude. By using transformers, it is easy to raise and also lower the voltage of alternating current. This means that it can be kept at lower levels for both industrial and domestic use, but raised to high levels for transmission.

Solar photovoltaic modules generate direct current (DC) electricity (they take the suns energy and convert it into DC electricity). Of course, the vast majority of electric current used in households is alternating current (AC). This is why an inverter is necessary: it inverts DC into AC. 
Direct current is an electric current that has a constant direction and a constant magnitude. An example of a source of direct current is batteries. With direct current, it is difficult to raise the voltage high enough for energy transfer and then lower it so that it is once again safe for domestic use. This makes it difficult to use for long distance power transmission.

Inverter is a device that converts the 12 V D.C. into 220V A.C.