Solar inverter: types of devices, overview of models, connection features

Possible connection schemes

When building a photovoltaic complex combined with a central network, there are different options for connecting the inverter.

Option #1 - circuit with DC charge controller

The most popular option, where the battery is charged through a solar controller MPPT (peak power point analysis).

The circuit uses a converter that supports the transfer of electricity to the network or load if the battery voltage exceeds a user-defined parameter.

Solution features:

• efficient use of renewable energy in the presence/disconnection of the network;
• the possibility of activating work from the solar system after the battery is discharged.

And also another solution is a slightly increased loss for energy conversion in the section "controller-battery-inverter».

Option # 2 - scheme with a hybrid and network converter

Network converter at the output of the battery inverter. According to the diagram, two converters are connected to different solar panels.

The hybrid converter is connected to the optional photovoltaic panel for recharging the battery, the mains converter is connected to the main solar module.

Under normal conditions (availability of mains current), the mains converter feeds the redundant load, the conversion efficiency is about 95%. Excess energy goes to the battery, and when it is full - to the general network

• uninterrupted operation regardless of the presence of the central mains voltage;
• high efficiency and minimization of losses on the DC side due to the sufficient voltage level of the solar battery;
• batteries almost always operate in buffer mode, which increases their service life;
• the use of hybrid inverters designed to charge the battery from the output;
• the need to adjust the operation of the network inverter.

The total power of the network converter should not exceed the power of the hybrid "converter" - this allows you to utilize the energy of solar panels in the event of a battery discharge, a power outage.

Regardless of the scheme chosen, a number of nuances should be taken into account when connecting the inverter:

1. Wired connections for DC should not be long. It is advisable to place the inverter in close proximity (up to 3 m) to solar panels, and then “build up” the line with AC.
2. The converter must not be mounted on combustible materials.
3. The wall inverter is located at eye level for easy reading of information from the display.

There are special requirements for connecting models with a power of more than 500 W. The connection must be rigid with reliable contact between the terminals of the device and the wires.

Also on our site there are other articles on solar energy and the connection of individual components and modules when assembling an autonomous system.

We recommend the following materials for review:

• Solar panels connection diagram: to the controller, to the battery and serviced systems
• Solar charger: device and principle of operation of charging from the sun
• How to make a solar battery with your own hands: how to assemble and install a solar panel

Foreign

The most famous French-designed converters are Schneider Electric, which are famous for their operating parameters, which make it possible to use them in areas with different climates. Their body is protected from corrosion by a special coating.

Conext by Schneider Electric

They were developed to improve the efficiency of batteries installed on the roofs of buildings. You can operate them even in the most difficult climatic conditions.The efficiency reaches 97.5%, the power is in a wide range - 3-20 kW.

The price range of the price is 86900-327300 rubles.

Design

It does not contain electromechanical capacitors, which dramatically increases the reliability of devices and increases the service life. Even at full load, the device delivers an efficiency of 97.5 percent. Some models do not have a distribution block, therefore, the installation of an electrical panel is not required.

From a huge range of devices with a power of 3-20 kW, everyone will choose the most suitable model.

Application of Capacitors and Flywheel Diodes in Autonomous Resonant Inverter Circuits

A certain increase in the conversion efficiency is achieved by introducing various additional elements into the circuit of resonant inverters. Most often, capacitors and the so-called are used. reverse diodes.

Capacitor C1 in Figure 6 is connected in parallel with the load if it has significant inductance. The purpose of this element is to maximize the parameter cosφ.

The essence of the application of the so-called. reverse diodes, which include back-to-back each key element, is to create conditions for the recovery of energy accumulated in reactive elements by returning it to a constant voltage source.

Any of the reverse diodes is locked in the open state of the key element and opens when it goes into the locked state, which allows you to “reset” the energy of the reactive elements L and C back to the “AND” source.

Inverter selection

The main function of the inverter is to convert standard battery voltage and DC current into 220V household AC. The voltage curve at the output of the inverter has a sinusoidal shape.And depending on which consumers will be connected to the power supply from the SB, the inverter must output voltage either with the correct sinusoidal shape of the graph (pure sine) or with a modified sine (meander). How exactly the voltage graph at the output of the inverter behaves depends on the characteristics of the device.

Some electrical appliances also work stably on a "modified sine": electric heaters, computers, devices with switching power supplies (certain TV models). Experienced users of our portal recommend purchasing inverters that give a "pure sine" output. The shape of the output signal is indicated in the characteristics of the device.

When choosing an inverter, you should pay attention not only to the shape of the output signal, but also to the power of the device.

• Rated power (working) should be 25-30% higher than the total power of consumers constantly involved in the work.
• The peak power of the inverter must exceed the power of a possible short-term load on the device. We are talking about the load that will arise in the event of the simultaneous inclusion of several consumers with high starting power (refrigerator, pump motor, etc.).
• The characteristics of the inverter also indicate the maximum power. It is less than peak, but more than nominal. This parameter indicates the permissible short-term load at which the device will work for several minutes (5-10 minutes) and will not fail.

The starting current of the refrigerator may not pull the inverter, but, fortunately, I have enough inverter power. Constant power - 2.5 kW, peak - 4.8.

The efficiency of the inverter is also of great importance when choosing a device. It determines the loss of electricity during operation of the device and can vary within the following limits: 85-95% (depending on the model). It is recommended to choose a device with an efficiency of 90% or more. After all, we will pay for the inverter once, but we will have to pay constantly for its low efficiency.

Inverters connected directly to lead-acid batteries must protect the battery from deep discharge. Most modern inverters have this feature built in. The load cutoff threshold can be set by the manufacturer, or can be adjusted by the user.

The lower threshold for cutting off loads from the battery is 10V-10.5V (in 12-volt systems) is standard. In fact, this is an emergency protection against deep battery discharge. Now about adjustable settings: there are inverters with adjustable settings, there are inverters without settings. Budget models have less functionality, expensive ones have more. The consumer himself determines what he needs more and at what price.

In addition to conventional converters, hybrid and combined inverters are often used in autonomous power systems. Combined - able to combine the functions of the controller and inverter. Hybrid - allow you to power consumers both from the network and from batteries.

You will learn about the cross-sections of conductors that connect various elements of an autonomous power supply system, about the parameters of protective devices and about the installation methods of the equipment used, in the final part of this article.

Types of inverters for SES

There are several types of network inverters, differing in some design features and purpose.When assembling a complex of solar panels, various options are used that require the owner to correctly understand the specifics and features of their work. First of all, inverters are distinguished by the shape of the output signal:

• sinusoidal
• rectangular
• pseudosinusoidal

sinusoidal

The most preferred design option is a sinusoidal solar inverter. It is able to produce the highest quality signal form, optimal for all household appliances, technical and electronic devices.

Rectangular

Square wave inverters are the cheapest, but are only recommended for simple lighting fixtures. Many types of household appliances from such sources cannot work.

Pseudosine

Pseudo-sinusoidal devices are a compromise between the first and second types, capable of working with any device. However, for some sensitive types of consumers, it is better not to use them. In addition, interference and noise can occur from pseudo-sine wave inverters.

In addition, there are inverters designed to work in different conditions. Let's take a closer look at them:

Network

Usually mains energy is used during the daytime, when solar batteries are being charged. At night, there is a transition to autonomous power, until the moment when the battery charge is exhausted. In the daytime, it is possible to transfer energy to the network if the batteries are full. This function is also used if the power of solar panels significantly exceeds the needs of the house.

Abroad, there are such programs and tariffs, where the given energy is taken into account and paid to the owner of the solar battery. There are no such opportunities in our country yet, therefore grid inverters for solar power plants are used only for supplying consumers and switching the power supply mode.

This type of device is considered the most successful because it works intermittently and has a high durability. Its disadvantage is the need to have a parallel connection to a centralized source.

Autonomous

Such a scheme involves high loads, so the inverter power is selected with a certain margin. In addition, it is necessary to provide inverter parameters that exceed the starting current of the most powerful consumer.

This is important because the peak value can destroy the device.

For example, a refrigerator or air conditioner at startup exceeds its operating capacity by 10 times, so it is necessary to have a certain margin. Before buying, you should calculate the total power of all consumers and take into account peak starting loads. In addition, it is necessary to add a margin to compensate for the decrease in output power over time.

Solar inverter Sila 3000

One of the most popular devices is the Sila 3000 hybrid solar inverter, reviews of which indicate high operational capabilities. For example, at a nominal value of 2.4 kW, these inverters are able to provide 3 kW for a short time without negative consequences for themselves. In the event of peak starting loads, Sila 3000 hybrid solar inverters can withstand a change in operating mode. Although they are made in China, the durability and reliability of the devices are highly appreciated by users.

Brief Overview of Famous Inverter Brands

ChintPower Systems Co.,LTD

This type of inverter is quite expensive. Country of origin China.Produces a pure sine wave with reduced noise of about 30 decibels. Power 1000 VA, voltage up to 230 volts. The power of the SB with this converter reaches 1200 watts. The price tag varies within 40,000 rubles.

Cyber ​​Power Inverter

It is considered a budget microinverter for solar panels. Outputs a pure sine signal. Great for low power appliances. Can automatically switch. Output power 200 VA. Output voltage 220 v. Performs a transition to the battery in 4 ms. Its cost is only about 5000 r.

Voltronic power

The device of this company has a built-in charge controller. It also has pure sine. It has a maximum power of 1600 watts. The output voltage is 230 v. The output frequency is 50 hertz. To purchase it, you will have to pay about 20,000 rubles.

To get the maximum output from the entire power plant, it is necessary that each component of the system harmonizes with each other.

MAP "Energy"

This company produces Russian-made converters. It creates inverters with a power of 800 - 1200 watts.

The following converter options come out of its conveyor:

• 3-phase.
• Pure sine inverters.
• Devices that borrowed additional energy from the battery.

Each of these devices is capable of charging the battery. This type is used everywhere for both domestic and industrial needs.

This company has produced a device with a power of up to 20 kW. This is her pride! It holds loads up to 25 kW.

Schneider Electric

This company produces solar inverters with good performance. These devices can be safely used in cloudy weather. The body is coated with anti-corrosion protection, which allows you to resist salt precipitation.

In the manufacture of the French company abandoned electrochemical capacitors. This gave her an advantage in the consumer market.

The efficiency of devices manufactured by this company is 97.5%. Using an inverter from this company, it is quite possible to build a solar power plant for 3-20 kW.

TBS Electronics

The company has been producing converters since 1996. Their devices are suitable for Poversine solar modules with power from 175 to 3500 watts. The metal surface protects it from various harmful factors. Good electronics allow it to work very reliably.

This type of device is protected against short circuits and overloads.

Kostal

Produces converters various types and capacities. Some appliances have a built-in AC switch. Many devices are already built into this device.

Anyone can use this device. It is easy to install and very convenient to use. The manufacturer gives a 5-year warranty. It is created according to European GOSTs.

Taiwan inverters ABi-Solar

These are autonomous SL / SLP and hybrids. They have built-in controllers for recharging the battery. Taiwanese developers have combined 3 devices in one device: a controller, an inverter and a charger.

The built-in screen will allow you to monitor the incoming data. Efficiency 93%. Some of these devices have protection against various dust.

The ABi-Solar SL 1012 PWM model delivers 800 watts of power. With it, it is easy to make the charging process automatic.

Manufacturer GoodWE

The Chinese manufacturer makes quality devices and sells them for a small price in Russia.With the help of special software, you can make calculations. This will allow you to squeeze the maximum efficiency out of the solar station.

You can control the operation of the installation using a regular mobile phone.

Thus, by installing the desired inverter for solar panels, you can be completely independent of the standard power supply.

Types of solar inverters

There are many varieties of these devices. And choosing them is not so easy.

Modified or grid inverters

The production is based on varicap diodes. They have a low frequency modulator. This allows for variation. They are perfect for round solar panels. Most of them have a conductivity of more than 40 microns. They have linings in insulators. There are even those that work through the recharging controller.

Rectifiers for inverters have a frequency of about 30 Hz, and sometimes even higher.

The network inverter for solar panels has the following advantages:

• Small size.
• Good protection.
• Low energy consumption.
• Fast voltage conversion.

Sometimes a controller is built into the inverter housing. Many sellers call this device hybrid. But in reality this is not so, it is combined.

hybrid inverter

Combines the features of all other devices of this type. This is the most expensive, but the most suitable inverter for solar panels.

The hybrid device can additionally acquire a load from the network and the battery. His priority is constant tension. If for some reason there is little current in the battery, then it will take it from the network.

Offline inverters

Perfect for SB of different power. They work even at the moment of overvoltage up to 4A. Going for 3 rounds.On them you can find the designation "OFF Grid". They do not contact the household network. Power can be from 100 - 8000 watts.

If there is a device marked On Grid, then this means that it has an additional function. It can control amplitude differences and frequency.

If the external network issues a fault, the autonomous inverter will turn off.

• On the multiple current side, the inverter is selected as follows from the rated power of the solar panels.
• If the total power of the devices used in the dwelling is less than the possible powers of the solar power plant, then the excess electricity produced enters the external electrical networks.
• If the power is not enough for the normal operation of home devices, then external recharge is carried out.
• In the absence of voltage, feeding is served from a charged battery. In the case when batteries are not integrated into the system, the energy made by the solar power plant goes into a single network.
• Grid-mounted photovoltaic inverters use the energy received from solar panels with great efficiency.

Main advantages:

1. The cost is within the normal range.
2. Change voltage quickly.
3. Work stably at high humidity.
4. Easy to install low varicap.
5. There is a frequency adjustment.
6. The electrical conductivity is reduced.

Signal is generated: 1) pseudo sinusoidal; 2) rectangular; 3) sinusoidal. The name miandrovye may occur. That is, it is not sinusoidal.

The first has the following features

Something in between the other two signals. Its features:

• Small cost.
• All appliances work great.
• Generates noise waves, interferes.
• Sensitive devices in the presence of this signal cannot work.

Characteristics of the second

This type is best used to transmit voltage to lighting devices.

Peculiarities:

• They work simply and clearly.
• The cost is low.
• Not protected from power surges.
• Not suitable for every household appliance. They may simply not be compatible with it.

Sinusoidal signal and its characteristics

They produce a good current with the desired sinusoid. Perfect for large household appliances.

Key Features:

• Protects equipment from sudden voltage changes.
• They are expensive.

What is the difference between network inverters and stand-alone inverters?

Autonomous are able to function without additional batteries. These devices work only with those devices that are capable of performing power control. When the power is normal, they connect automatically and generate electricity. They have standard sockets.

Network require devices that will charge the battery. They also have special things that allow you not to mix up the polarity when connecting. They control battery charging.

Overview of popular hybrid converters

Among consumers, inverters from foreign companies received good reviews: Xtender (Switzerland), Prosolar (China), Victor Energy (Holland), SMA (Germany) and Xantrex (Canada). The domestic representative is MAP Sine.

Xtender Multifunction Inverter Range

The Studer hybrid converter from Xtender is the epitome of the Swiss quality standard in power electronics. Solar inverters of the Xtender series are characterized by impressive strength characteristics and extensive functionality.

Variety of models: XTS - low power representatives, XTM - medium power models, XTN - high power inverters.

Xtender power ranges: XTS - 0.9-1.4 kW, XTM - 1.5-4 kW, XTN - 3-8 kW. Output voltage - 230 W, frequency - 50 Hz

Each Xtender hybrid converter series has the following features and options:

• pure sine wave feed;
• "mixing" power to the network from the battery;
• when the mains voltage decreases, the consumption from the central power supply is reduced;
• two priority selection modes: the first is “soft” with mains recharge within 10%, the second is full switching to the battery;
• variety of installer settings;
• management of the standby generator;
• standby mode with a wide range of regulation;
• remote monitoring of system parameters.

All modifications have the Smart Boost function - connection to different "suppliers" of power (generator set, grid inverter) and Power Shaving - guaranteed coverage of peak loads.

Optimal Prosolar Hybrid Inverters

The Chinese-made model has good characteristics and reasonable cost (about $1200). The converter optimizes the performance of the solar panels by storing unused energy in the battery.

Specifications: voltage shape - sinusoid, conversion efficiency - 90%, unit weight - 15.5 kg, permissible humidity - 90% without condensation, temperature -25 °С - +60 °С

Distinctive features:

• option to track the limiting power point of the solar battery;
• informational LCD display showing the operating parameters of the system;
• 3-level battery charger;
• adjustment of maximum current up to 25A;
• communication of the inverter.

The converter is connected to a PC via software (supplied as a kit). It is possible to upgrade the inverter by innovative flashing.

Phoenix Inverter Sine Wave Inverters

Phoenix inverters meet high requirements and are suitable for industrial applications. The Phoenix Inverter series is released without a built-in charger.

The converters are equipped with a VE.Bus data bus and can be operated in parallel or three-phase configurations.

Power range of the model range - 1.2-5 kW, efficiency - 95%, voltage type - sinusoid.

The table shows the characteristics of the hybrid modification of the 48/5000 inverter from Victron Energy. Estimated cost of Phoenix Inverter with a power of 5 kW is 2500 USD.

Competitive advantages:

• "SinusMax" technology supports the launch of "heavy loads";
• two energy saving modes - load search option and idle current reduction;
• the presence of an alarm relay - notification of overheating, insufficient battery voltage, etc.;
• setting of programmable parameters via PC.

Up to six converters can be connected in parallel per phase to achieve high power. For example, a combination of six 48/5000 units can provide an output power of 48kW/30kVA.

Domestic devices MAP Hybrid and Dominator

MAP Energia has developed two modifications of the hybrid converter: Gibrid and Dominator.

The power range of the equipment is 1.3-20 kW, the time interval for switching between modes is up to 4 ms, it is possible to “pump” electricity into the city network.

Comparative table of converters capabilities.Both types are capable of operating in ECO mode, each model "communicates" with a Web server for remote monitoring and adjustment

General characteristics of voltage converters Hybrid and Dominator:

• torus-based transformer;
• there is no input voltage stabilization;
• power "pumping" mode;
• output - pure sine;
• generation of excess energy in the network;
• limiting the current consumption at the AC input;
• class IP21;
• consumption in "sleep" mode - 2-5W.

The efficiency of converters reaches 93-96%. The devices have been successfully tested for use at ultra-low temperatures (limit value -25°, short-term drops to -50°C are acceptable).

Transmitter Selection Criteria

When choosing such an element of a solar system as an inverter, not only the geometry of the output signal is important, but also its power. Experts advise equipping solar panels with converters, the rated power of which is 25-30 percent higher than the total power available in the volume of 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 the energy loss for accompanying processes. Depending on the model, it has a different value, which is in the range of 85-95%. The optimal choice is an efficiency of at least 90%.

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

Manufacturers of quality equipment complete 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 can also be different. In this matter, one should be guided by the following recommendations: if the power of solar panels does not exceed 5 kW, then one inverter is enough for such a system. Larger batteries may require 2 or more inverters. Optimally, when there is one inverter for every 5 kW.

Hybrid inverters are used to work in a grid that combines the use of standard electricity and energy supplied by solar panels. The article recommended by us will acquaint you with the features of the device and the rules for their selection.

Converters can differ from each other in circuits, geometry of the output signal, and other defining quantities. Separate converters complete with chargers. If one of the inverters fails, the system will not stop working.

Benefits of Inverter Batteries

Modern homes are often subject to power surges and power outages. The heating system suffers the most from this, since in most houses water is heated using electricity. The presence of constant electricity affects the smooth operation of the gas boiler. Circulating pump and control automation.

If the heating boiler stops, it is likely that the pipes through which water passes will break, which will lead to the destruction of finishing materials and the appearance of cracks in the building structure.Inverter batteries have gained wide popularity in recent years and began to displace individual generators. Inverters work thanks to the fact that special batteries supply it with a power source.

Advantages of the inverter:

Sound and quick turn on. The inverter starts up silently: no one even notices how the battery power of the inverters starts up.

Noiseless at work. If the fuel-fired generators are very noisy, then the inverter makes no noise at all.

No exhaust

When using generators, it is important to think carefully about the location and exit of the pipes through which the gases leave the room. The inverter does not emit exhaust gases.

fire safety

The inverter does not require fuel, which reduces the risk of fire.

Mobility. The inverter can be located in any convenient place.

When placing the inverter, it is important to pay attention to the fact that the room must have high-quality thermal insulation. The use of inverters is not only efficient, but also profitable. Of course, its purchase and installation will cost money, but in the future, inverters will pay off and save a lot of money.

Of course, its purchase and installation will cost money, but in the future, inverters will pay off and save a lot of money.