What Does A Solar Inverter Do?

Solar Inverter Technology

All over the world, many people have developed a keen interest in renewable energy sources. As a result, interest in solar systems has grown tremendously since this is the most common type of renewable energy source. The use of solar energy is a great life hack that directly contributes to the conservation of the environment and saving on electricity bills.

Similarly, solar energy is efficient and more convenient since the sun shines almost daily for long hours. Solar energy is trapped through the solar system. So, what is a solar system? How do solar systems function? The solar system, also known as the PV system, comprises a solar panel (PV panels), a solar inverter, a solar battery (though not all solar systems), and a rack, among others.

Other solar systems also use electric meters. You can have as many solar panels as possible depending on the volume of energy output you need. A solar inverter is an expensive but essential component of the solar system. Therefore, you must know what it does and the factors to consider when choosing the best solar inverter for your solar system. Keep reading for more insight!

What Is A Power Inverter?

A power inverter is a device that converts direct current (DC) to alternating current (AC) per the set voltage output and relevant frequency. Power inverters can function separately as a backup power source from separate, fully charged solar batteries. They could also be used as independent equipment for other applications such as solar power.

You could use an inverter in another configuration as part of a larger circuit, such as a UPS or a power supply unit. In such situations, the inverter input DC comes from the rectified mains AC in the PSU when power is present and from the batteries in instances when there is no power.

There are several types of power inverters depending on the shape of the waveform. The various kinds have distinct efficiencies, circuit designs, pros, and cons. The most frequently used power inverter is the solar inverter. The solar inverter converts the direct current from a PV solar panel to an alternating current, which is fed into the electrical grid and used domestically at home.

Main Types Of Inverters

There are three primary types of inverters based on the output characteristics. These are Square Wave, Sine Wave, and the Adjusted Sine Wave inverters.

Square wave inverter

This inverter has a square wave output waveform of the voltage. A square wave inverter is the least used compared to the other types of inverters because almost all equipment is designed for the sine wave supply. There are high chances of damage to equipment when the square wave is supplied to sine wave-based equipment.

Although this application is seldom accessible, it is one of the least costly types of inverters. In most instances, a square wave inverter supports universal motors.

Sine wave inverter

This inverter has a sine wave output waveform of the voltage and produces similar output to the output in electricity. These inverters are designed for equipment that uses sine waves. A sine wave inverter is the most appropriate for most appliances and guarantees safe usage. However, sine wave inverters are costly. These types of inverters are primarily used in commercial and residential equipment.

Adjusted sine wave inverter

These types of inverters are more complex than the square wave inverter but more straightforward to use than the sine wave inverter. Its output waveform is neither an exact square wave nor a sine wave. Adjusted sine wave inverters use basic technology as compared to the other types of inverters.

As a result, it produces adequate power for simple electrical appliances. They are easily affordable and more efficient. Moreover, they are the most effective inverters for less sensitive equipment such as heaters, air conditioners, telephones, and chargers.

Other Types Of Solar Inverters

Battery inverters

For those who are enthusiastic about solar panels and would like to use one, battery inverters are the best option, especially for fitting into your home solar system. Similarly, you could use battery inverters separately from your solar panel. A battery inverter converts the battery power into a 240V alternative current that can be fed into the switchboard instead of the grid power.

Central inverters

A central inverter is the best choice for appliances that require a lot of kilowatts or even megawatts. These inverters are very big and look like a large metal cabinet. Every cabinet of a central inverter can hold up to 500kW of power and above. Central inverters are primarily used for commercial purposes in large-scale installations or utility-scale solar firms and not for residential purposes.

Hybrid inverters

Multi-mode inverters enable the user to connect the batteries to the solar system. These types of inverters are rare in Australia. Hybrid inverters communicate with the connected batteries through the direct current coupling, which occurs when the solar panel and the batteries use a single inverter.

As such, the direct current from the solar panel is used to charge the batteries through a direct current charger. Their electronics regulate the charging and discharging of the batteries.

Micro inverters

Microinverters are small in size, and their ratio to the solar panel is 1:1. Microinverters are known for their energy efficiency, especially during harsh conditions, since they optimise every solar panel individually.

String inverters

These are the most prevalent type of inverters for residential purposes. Every solar installation requires only a single string inverter. The name string inverter is derived from the fact that the string inverter always has a string of solar panels connected to it.

What Exactly Does A Solar Inverter Do?

Home appliance's function using alternative current and not direct current. Therefore, a solar inverter takes in the variable direct current from the solar panels and converts it to the alternating 120V/240V current. Simply put, the sun's rays fall on the solar panel having photovoltaic (PV) cells made of semiconductor layers of crystalline silicon or gallium arsenide.

These layers have negative and positive layers connected through a junction. During the day, the semiconductor layers absorb the light from the sun and transfer the energy to the PV cells. This energy travels as it knocks the electrons loose, thus moving between the negative and positive layers. This movement produces an electric current referred to as direct current.

The direct current is stored in the solar battery for later use or transferred to the solar inverter, depending on the type of inverter you have in your home. When the energy reaches the solar inverter, the inverter will run it into a transformer where it is converted from the direct current to alternating current.

In a complete installation of a solar system, the basic unit consists of a control circuit, an oscillator, switching devices, a transformer, and a drive circuit for power equipment. The switching devices, which are turned on and off with the transformer, facilitate the conversion of DC to AC.

Power transistors

These devices, such as a power transistor, feed the direct current to the primary side of the transformer. In the primary side of the transformer at the optional winding, the changing voltages lead to the induction of the alternating current. The transformer, operating as the amplifier, expands the output voltage ratio determined by the turn ratio.

This process leads to extending the output voltage from the standard 12 volts from the solar battery to either 120 volts or 240 volts. Moreover, an inverter can communicate with your computer providing you with the data concerning the amount of energy that is supplied, the energy used by your appliances, and any errors.

Modern inverters have a modification that enables them to send error reports and even weather reports for users who want such information. Additionally, an inverter offers protection to the energy grid from dangerous over-voltage.

This will also protect your appliances from damage caused by over-voltage through the protection of the grid. Over-voltage mostly occurs in rural areas. The inverter will shut down the entire system in such circumstances instead of sending the over-voltage to the grid.

Solar regulations

More recent regulations concerning solar systems have mandated manufacturers to ensure that inverters have a monitoring system. Such monitoring systems are found in low-cost solar inverters in the form of flashing lights. In contrast, the high-cost solar inverters can notify you with updates on the performance of your energy system.

Through the yield data provided by the monitoring system, you can assess whether your system is in good working condition. It also enables you to manually reset your inverter should there be a need. However, most inverters have an automatic reset function.

The monitoring system further enables you to check the amount of power supplied by your system. Thus, it is an easier way to keep track of any shortages. This would provide you with ample time to remedy the situation.

Considerations Before Buying A Solar Inverter

Different types of solar inverters vary in size, design, and appearance. Therefore, it would help to consider the factors below before deciding on which solar inverter to buy.

CEC approval

Before purchasing a solar inverter, it is essential to ascertain that it is CEC approved. The Clean Energy Regulator maintains a list of approved inverters that every person intending to buy an inverter should be aware of.

What it means for an inverter to be approved by the Clean Energy Regulator is that the inverter is suitable and safe for Australian climatic conditions per Australian standards. Such approval would also mean that the inverter is of good quality and thus effective.

Size of the solar inverter

Most people ask questions such as, "What size of solar inverter is best for my solar system?" Well, to be precise, there is no better size of a solar inverter than the one prescribed by the manufacturer of your solar panel. Every solar panel comes with a description of the appropriate inverter for the system.

In most cases, the inverter size is dependent on the amount of power produced by your solar panels. However, there are specific exceptions when it comes to this rule. You could purchase a solar inverter whose rating in kilowatts is more than the output of your solar panel. It is discouraged to buy a solar inverter whose rating in kilowatts is lower than the energy output of your solar panels.

Weatherproof

You want to have a long-lasting solar inverter; therefore, you must check if the solar inverter you want to buy is weatherproof or not. Weatherproof solar inverters are more convenient and would not cause any challenges, even if you plan to install them outside the house.

However, not all solar inverters are weatherproof; some are not weatherproof and will thus force you to spend extra cash in purchasing the protection cage for your solar inverter.  Weatherproof solar inverters can stand shady weather conditions and will most likely last longer.

Suppose the solar inverter that interests you is not weatherproof. In that case, you could ask the company you are buying it from if they will organise its cage installation or whether you need to purchase a separate protection cage for your solar inverter.

Display of the solar inverter

The solar inverter display contains certain important information required for the installation and operation of the inverter. For instance, the display of the solar inverter provides information concerning the general kilowatts of the inverter, the kilowatts produced daily, and if there are any remote-control functions.

Warranty

Solar inverters do not have equal warranties. The warranties depend on the inverter type and whether they are connected to the grid. Generally, solar inverters have warranties ranging between five and twelve years, whereas most grid-connected solar inverters have warranties of between ten to twenty years.

A warranty ensures protection for your inverter, among other privileges. Remember that the more extended the warranty, the more protection you will have for your inverter.

Grid connection

Another important consideration is whether you will be connected to a grid. Should that be the case, you should have an inverter with an efficiency of at least 95% for transformer-less inverters and at least 93% for transformer-based inverters.

How Much Does A Solar Inverter Cost?

Now that you are aware of what a solar inverter is, the types of solar inverter, and what a solar inverter does, you might want to know how much a solar inverter would cost you. Precisely, there is no standard price for a solar inverter. The fees range depending on the type of inverter, size of the inverter, and the manufacturer you buy from.

However, one clear fact is that solar inverters are slightly expensive. Whereas it is always tempting to buy a cheaper solar inverter, it is essential to remember that cheap is always expensive in the end. To ensure you get the best inverter for your needs, contact expert solar installers to handle the whole process for you.