Normally in electrical systems, a current has two different descriptions, DC and AC.

Direct Current (DC): In such electrical systems, current has the same value as voltage. For example, a system that has 50V value constantly feeds on 50V voltage. In the graphic below, you can see voltage-time graphic in detail. Here you can see how voltage is constantly steady.

Alternating Current (AC): Today, all the devices that work through the grid, work with AC systems. The most important feature of this system is that the voltage between two tips constantly changes. In the graphic below, you can see how voltage changes according to time.

The main function of solar power inverters is to change the DC system which is stored in accumulators and batteries into AC system which is used by devices that work through grid. In short, it provides the transformation from DC to AC. We will examine solar power inverters that come with many different power and voltage options in detail shortly.

There are two different connection points as input and output. By connecting the DC system to input part, AC power is obtained from the output part. But, how do solar power inverters carry out this transformation process? There are Convert Unit: Here, the voltage comes as DC to the system and is converted into AC by means of transistors and other electronic components. For example, if 10V DC voltage comes into the system, unsynchronized MOSFET and BJT transistors or special integrated circuits made specifically for this purpose, produce voltages changing between -10V and +10V periodically.

There are two different power inverter types according to the grid connections:

Stand Alone (Off-Grid) Inverters: They are the inverters that work separately from the grid. Electronic devices are connected to the inverter output directly. The main reason why they work separately from the grid is because there is no hardware that would enable them to work synchronously with the grid.

Stand-Alone inverters have DC input and AC output units. Output wave doesn't necessarily have to be full sine. They can have modified sine or true sine output structures. We will go into detail on those wave types shortly.

Grid Tie (Synchronous) Inverters: These are the inverters that are connected to the grid. The sine wave of the grid shows V-T (voltage-timing) compatibility. When the voltage of the grid has pick value, the inverter output voltage is also the same.

Since grid tie power inverter systems are connected to the grid, they may keep on working even though the electricity is on. There is no need to connect the devices to the inverter output separately. Connecting the inverter output to the grid appropriately will be sufficient. In the picture below you can see grid-tie power inverter connection.

The difference between grid-tie inverter and stand alone inverter

1.) While Grid-Tie works with the grid online, stand alone systems work separately from the grid.

2.) While grid-tie inverter outputs are full sine, stand alone inverters can produce outputs such as square, modified sine or true sine. Almost all electronic devices that work with AC voltage can work with these wave outputs.

3.) Since grid tie inverters have more complex electronic systems, they are more expensive than stand alone inverters which actually have the same features.

4.) You can find grid tie inverters in the market with more power and voltage options. It is a more commonly used product.

5.) You can collect the electricity that you give to the grid with grid tie inverters, from the government. There are many legal regulations and incentives in America, Britain, France and many other countries regarding this issue.

There are three type Power Inverters for different Output Wave:

a.) Square Wave Power Inverters: This is the inverter type which gives square output waves. This is the cheapest and easiest inverting process. Square wave output can make almost all grid devices work between 50 – 60 Hz. But there is a possibility that this inverter may harm these devices if used long-term. In the picture below, you can see 110V AC square wave output.

b.) Modified Sine Wave power Inverters: Output wave is square but it undergoes a special process to make it more similar to sine. Modified sine wave is a more commonly used method than square wave. It can make all AC devices work. You can't connect such devices to the grid online because grid voltage is pure sine. In the picture below, you can see modified sine waveform.

c.) True Sine Wave power Inverters: These are the inverters whose output wave type is pure sine. There is no difference between the grid voltage and this inverter output. If they have the necessary electronic hardware, they can be connected to the grid online. In all grid tie inverters, this wave technology is used. In the picture below, you can see true sine waveform.