Inverter for solar panels: types of devices, overview of models, connection features

Solar systems around the world are developing at a tremendous pace. The International Energy Agency noted in its annual report that in 2016...The number of commissioned solar power plants exceeded the number of coal ones for the first time.

The heart of a solar energy system is an inverter for solar panels, whose task is to transform direct current into alternating current. We will tell you how to choose the best device option and how to install it correctly. Taking into account our recommendations, you can assemble a flawlessly operating mini power plant.

Types of inverters for solar panels

Without an inverter, the energy generated by the solar system will be completely useless for domestic needs. There are 3 types of inverters according to type of use:

• autonomous;
• network;
• multifunctional.

Inverters of the first type are designated “off grid”. They are connected to the solar module, are part of a separate photovoltaic system and have no contact with the external electrical network. Their power varies from 100 to 8000 W.

Synchronous or grid-tied inverters operate synchronously with the centralized power supply system. Converters with the designation “on grid” not only perform the role of a converter, but also correct such network parameters as amplitude differences, frequency indicators and others.

If there is a problem in the external network, the inverter automatically turns off. Such inverters store electricity in batteries.

If the total power of the appliances used in the house is less than the potential capabilities of the solar power plant, then the excess generated electricity ends up in external electrical networks. If the power is not enough for the normal operation of household appliances, then recharge is provided from the outside.

The inverter parameters on the AC side are determined based on the total power consumption of all devices connected to the consumer's electrical network. On the DC side, the inverter is selected based on the rated power of the solar panels

In the absence of voltage, power is supplied from a charged battery. In the case when batteries are not included in the system, the energy produced by the solar power plant goes into the general network.

Grid-connected photovoltaic inverters use the energy obtained from solar panels with great efficiency. They are a guarantee of stability of power supply and are characterized by high efficiency exceeding 90%

A hybrid or multifunctional inverter is reliable equipment. It combines the properties of the first two converters and has a large number of settings. This is the best option for setting up a home solar station, but also the most expensive.

All existing solar inverters are divided into types and according to output voltage. Depending on this parameter, they are sinusoidal and meander.Since the first has an output voltage almost the same as that of the mains supply, this is a good option when there is highly sensitive equipment in the house.

A constant voltage value is a guarantee of safety for home electrical equipment. Graphically, the output signal shape of such a sinusoidal type inverter is depicted as a pure sine wave.

When operating equipment, the best meander shape is an ideal sine. This is especially important for telecommunications equipment, medical equipment, and high-precision measuring instruments, therefore, even despite the high price of complex inverters, there are no other options in this case. Manufacturers indicate information about the shape of the output signal in its characteristics

Square-wave or non-sinusoidal converters, unlike sinusoidal ones, have an output signal geometry in the form of rectangular pulses, the so-called modified sine. Inverters of this type cannot be used for certain types of load, but for devices that use the active component of power, they are quite suitable.

Converter selection criteria

When choosing a solar system element such as an inverter, not only the geometry of the output signal is important, but also its power. Experts advise staffing solar panels converters whose rated power is 25 to 30 percent higher than the total power available in the equipment.

It is also necessary to take into account the load that occurs when several devices with high starting power are turned on at the same time.

Another criterion when choosing an inverter is its efficiency, which determines energy losses for related processes.Depending on the model, it has a different value, ranging from 85-95%. The optimal choice is an efficiency of at least 90%.

Inverters are available in both single-phase and three-phase types. The former have a lower cost, but their choice is justified when the power consumption is less than 10 kW. Their voltage is 220V and frequency is 50Hz. Three-phase inverters have a wider voltage range - 315, 400, 690V.

Manufacturers of high-quality equipment equip their products with output transformers. There is a relationship between the weight of the inverter and its technical characteristics - if for every kg of its mass there is 100 W of power, then the transformer is included in its circuit

The number of inverters in the system may also vary. In this matter, you should be guided by the following recommendations: if the power of solar panels does not exceed 5 kW, then one inverter is sufficient for such a system. Larger batteries may require 2 or more inverters. It is optimal when there is one inverter for every 5 kW.

To operate in a network that combines the use of standard electricity and energy supplied by solar panels, hybrid inverters. Our recommended article will introduce you to the features of the device and the rules for choosing them.

Converters may differ from each other in circuits, output signal geometry, and other defining quantities. Some converters are equipped with chargers. If one of the inverters fails, the system will not stop operating.

Features of connecting the inverter

The efficiency of the entire solar system depends on the correct connection of the solar inverter.The main thing is to follow the rule: a cable transmitting direct current must have a minimum permissible length and a maximum cross-section.

If the consumer is located far from the solar cells, the electrical cable transporting 220 V alternating current should be extended by extension. The length of the wire between the inverter and the solar panel should vary within 3 m and no more.

The best option is when the inverter is located near solar battery. Particularly stringent conditions must be met when connecting inverters with a power exceeding 0.5 kW.

The connection of the wires must be strong, because an insufficiently tight connection causes sparking, which can become a source of fire. When installing an autonomous inverter to ensure uninterrupted power supply to the facility, the DC circuit must be completed automatic switches.

The best solution when connecting an inverter is to use a hybrid type piping for both direct and alternating current. The principle is based on a special order of turning on the converter. It includes solar panel controller after the batteries are charged.

This solution increases the quality of equipment operation. In regions where power is often cut off, or in homes located in areas where cloudy weather prevails, this option works very effectively.

Review of inverter models

Converters for solar panels are produced by many manufacturers, both domestic and foreign. All equipment has different characteristics, quality levels, its own set of functions and technical capabilities.

Inverters from domestic manufacturers

A wide range of these products with a power of 800 - 1200 W is produced by the Russian manufacturer MAP Energia.

The company produces several lines of inverters:

1. Sine wave inverters with a pure sine waveform - SIN MAC.
2. Sinusoidal converters with the function of selecting additional energy from batteries - MAP HYBRID.
3. Three-phase inverters - MAP HYBRID 3 phases.

Inverters produced by this company can charge all types of batteries. For this they have Charger high power.

The company's achievement is an inverter with a record power of 20 kW, which can withstand the highest load of 25 kW. This model can provide reliable power to a large residential building with a lot of equipment.

MAP Energia inverters are used not only in private households, but also in many industries. They are used in medicine, construction, and at weather stations.

Schneider Electric Conext drives

The French company Schneider Electric produces inverters with high performance characteristics that allow them to be used in different climates.

The housing's highly corrosion-resistant coating allows it to successfully pass salt spray testing. They are intended for solar panels installed both on the roofs of private cottages and apartment buildings.

The manufacturer checks the reliability of its equipment using various methods and tests. Conext inverters are designed without electrochemical capacitors, which guarantees long-term operation.

Conext inverters, even at maximum loads, have an efficiency of 97.5%.Some models are equipped with a distribution block, so there is no need to install an external electrical panel

A large range of products allows you to choose the appropriate model for solar systems with a power of 3 - 20 kW.

Inverters from TBS Electronics

This Dutch company, present on the market since 1996, produces both low-power and higher-power sine-wave converters for Poversine solar panels with rated power from 175 to 3500 W.

The photo shows a model of the professional inverter Powersine PS3500-24. It can be used to provide continuous power to heating boilers, pumps, computers, and other small loads. It is equipped with reliable electronics, a highly durable metal housing

The Powersine line is characterized by a very pure sine wave at the output, so the use of these inverters guarantees competent and long-term operation of highly sensitive devices. The equipment is equipped with protection against short circuits, temperature surges, and overloads. With these inverters, you can run loads up to 500V with a starting force tens of times higher than the rated power.

Network inverters Kostal

The company produces innovative high-quality inverters with a power from 1.5 to 20 kW, both single and three-phase. The design includes an automatic AC switch, MPP trackers, a monitor, an S0 meter and many other options as standard. All this makes it possible to implement the inverter into the “smart home” system.

Kostal inverters are easy to operate and install. The built-in panel is informative and clear, allows you to monitor its operation

Due to the high quality of the housing material, the converter is installed both outside and inside the house.The assembly is carried out in Europe, so the quality meets European standards. Manufacturer's warranty - 5 years.

ABi-Solar inverters from Taiwan

These inverters, manufactured in Taiwan, are represented on our market by a series of autonomous SL/SLP converters, autonomous-grid hybrid inverters (NTH), and a line of HT hybrids.

Autonomous converters are equipped with charge controllers from solar panels. This equipment is endowed with triple functionality - it works as an inverter, controller, and charger.

The design includes a liquid crystal display that allows you to control the main parameters of the solar system. The efficiency of SL/SLP inverters is about 93%. SLP models have dust protection.

The budget option includes an inverter from the new ABi-Solar HTP series. It only works if there is a battery. Particularly popular is the NT series, which includes single- and 3-phase hybrid inverters with excellent build quality.

Converters SL0912 and SL1524 are also budget ones. They operate in 2 modes - household uninterruptible power supply and with solar panels. They have 2 voltage maintenance modes: from 180 to 260V and from 100 to 300V.

The second mode allows you to increase the battery life due to less use, but can only power equipment that is not very sensitive to the quality of electricity.

The ABi-Solar SL 1012 PWM inverter has a power of 800 V. The output current has an unmodified sine wave. Can be used for the sale of electricity produced by solar panels at a “green” tariff

ABi-Solar inverters make it possible to increase the operating temperature range batteries and automate the charge-discharge process.

Grid inverters from GoodWE

This Chinese company produces network inverters of various capacities and supplies them to the market at a low price. The inverter is accompanied by a special program that allows you to calculate the solar system, taking into account the location of the solar panels in relation to the cardinal points and other landmarks.

It is possible to monitor the operation of the converter via a tablet or smartphone, but you will first have to install a specially designed application based on the Android operating system.

Conclusions and useful video on the topic

Here the manager of the selling company talks about the principles of choosing an inverter:

This video covers the issue of connecting an inverter:

The photovoltaic grid inverter, as an integral part of the solar system, allows you to gain complete independence from the centralized power supply and rising prices for electrical media.

Smart systems that include a grid converter make energy consumption accessible, reliable and manageable. At the same time, the comfort in the home is not disturbed in any way.

Would you like to tell us how you assembled your own mini-power station with an inverter for solar batteries? Do you have valuable information on a topic that could be useful to site visitors? Please write comments in the block below, post photos and ask questions.