What is an inverter and how does it work?

Learn to Repair Inverter

UPS or Inverter is a very useful device. Where electricity is a problem, it is needed.

There are many types of inverters, here we are talking about battery backup inverter. Battery backup inverters come in a variety of sizes and wattages.

There are two types of inverters in the market namely sine wave and square wave. A square wave inverter is cheaper than a sine wave inverter. There is a difference in the waveform of the output voltage in the sine wave and square wave inverter. A few years back people used to use square wave inverters only because sinewave inverter technology was not so advanced and sine wave inverters used to be very expensive. But nowadays there is not much difference in the price of sinewave inverters and square wave inverters.

If you use a square wave inverter then your fan and inductive load will make noise. But there is no such problem in the sine wave inverter.

Inverters up to 2kva are used in the house, in which 1 or 2 batteries are used, meaning this inverter is of 12Volt or 24Volt. In the absence of electricity or when the power grid is out, we can run the home appliances on the inverter.

Large inverters are used in commercial places in which 100 or even more batteries are used.

UPS of rating above 1000 kVA are used in the industry.

Now let's talk about the small household inverter.

First, let us understand Square Wave Inverter.

The square wave inverter has 2 channels in which push-pull technology is used. And a large size transformer is used in this, this transformer steps up the DC 12 voltage of the battery into 230 volt AC.

So first let us understand the circuit board of the square wave inverter.

The circuit board of the inverter is made up of different sections.

It mainly consists of 1) inverter section, 2) charging section, 3) change over the section, and  4) protection section.

section-wise function

Inverter Section: The inverter section converts DC 12volt to 230Volt AC.

Charging Section: The job of the charging section is to charge the battery when electricity is available.

Change Over Section: Change over the section of the inverter automatically starts power at home when the power comes on or when the power goes out.

Protection Section: A low battery and overload section is made in the inverter to avoid battery deep discharge and to avoid damage to the inverter if the load exceeds the capacity.

Now let us understand the inverter section in detail.

1) Inverter Section: 

Various PWM ICs are used for square inverters. Most of these used the SG3524, SG3525, TL494, and nowadays microcontroller-based circuit boards are used. By using a microcontroller IC, the size of the circuit board becomes smaller.

Through this IC or through the driver section the pulses are given to the gate of the Mosfet. And the drain of the mosfet is connected to the inverter transformer.