How Does an Inverter Work

Basic Function of Inverter

Homes are designed to run off an AC Supply and they get that from the electrical outlets which all provide AC electricity, however, electricity produced by things such as solar panels and batteries produce DC electricity.

So, if we want to power our electrical devices from renewable sources, battery banks, or even our car, then we need to convert DC electricity into AC electricity. And we do that with an inverter

Fundamentals of Electricity

Free Electrons

We first need to understand some fundamentals of electricity. Inside a copper wire we find copper atoms. These have electrons; these are known as free electrons because they are free to move around. They will randomly move in all directions. but this isn’t of any use to us. We need lots of electrons to move in the same direction. And we do that by applying a voltage.

The voltage is like pressure and will push the electrons when we connect a wire to the positive and the negative terminals of a battery.

DC Electricity

Direct current (DC) is one-directional flow of electric charge. The electric current flows in a constant direction, distinguishing it from alternating current (AC).

AC Electricity

Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences

The Main Action of Inverters

The inverter consists of a number of electronic switches known as igbts. The opening and closing of the switches is controlled by a controller. These can open and close superfast to control the flow of electricity. By controlling the path, which the electricity takes, and how long it flows in the different paths. We can produce AC electricity from the DC Source. 

Types of Inverters for Solar Panels

String inverters (Central Inverter)

Grid-tied string inverters are the most popular type of inverter.

They are designed to deliver AC power from a string of solar panels to your home and electricity grid.

They look like a large shoebox and are wall-mounted inside your garage or house. The DC production of the solar array is transferred to the central inverter to be converted into AC electricity. The inverter is connected to the utility grid and to the house power circuit.

String Inverters  +  Power optimizers

Power optimizers are small units located on the back of each solar panel. These work in tandem with a string inverter or central inverter to convert DC to AC by conditioning the Direct Current electricity from each panel and sending that conditioned DC to the string inverter.

Power optimizers, make it so if one of the solar panels is shaded it doesn’t hurt the overall performance of the system, it will not degrade the output of the entire string. Which can happen if not using power optimizers

Power optimizers also have the benefit of allowing panel-level monitoring

Microinverters

Micro-inverters are a small unit underneath or built into each individual solar panel instead of one big inverter for all solar panels

This gives each solar panel the ability to function at peak performance, independent from its neighbors. Even if the panel next to it gets obstructed somehow, the other panels can continue to convert at full capacity.

This also allows you to analyze performance of each individual solar panel. This is very helpful for spotting any issues and lessen repair cost because you have a finer view at finding problems in the system

Microinverters can be more expensive than string inverters, but it could pay off by getting more power from your system overall and allows you the flexibility of adding more panels down the road without having to get another main string inverter making solar panel systems easier to modify