Heliosystems around the world are developing at a tremendous pace. The International Energy Agency, in its annual report, noted that in 2016 The number of commissioned solar power plants for the first time surpassed the number of coal.
The heart of the solar energy system is an inverter for solar cells, the task of which is to transform a constant form of current into an alternating one. We will tell you how to choose the optimal variant of the device and how to correctly install it. Taking into account our recommendations, you will be able to assemble a flawlessly operating mini power station.
The content of the article:
- Types of inverters for solar panels
- Transducer Selection Criteria
- Features of the inverter connection
Overview of inverter models
- Inverters from domestic manufacturers
- Schneider Electric Conext Converters
- TBS Electronics Inverters
- Network inverters Kostal
- ABi-Solar Inverters from Taiwan
- Network inverters company GoodWE
- Conclusions and useful video on the topic
Types of inverters for solar panels
Without an inverter, the energy produced by the heliosystem will be completely useless for domestic needs. There are 3 types of inverters by type of use:
Inverters of the first type are designated "off grid". They are connected to the solar module, are part of a separate photovoltaic system and are in no way in contact with an external electrical network. Their power varies from 100 to 8000 watts.
Synchronous or network inverters operate synchronously with the centralized power supply system. Converters with the designation “on grid” not only play the role of a converter, but also adjust network parameters such as amplitude drops, frequency readings, and others.
If there is a problem with the external network, the inverter automatically shuts down. Such inverters accumulate electricity in batteries.
Autonomous inverters ensure the independence of the power supply at home from the work of a centralized source. The parameters of the inverter from the side of alternating voltage are determined on the basis of the total power consumption of all devices connected to the electrical network of the consumer. On the DC side, the inverter is selected based on the rated power of the solar panels.
If the total power of the instruments used in the house is less than the potential capacity of the solar power plant, then the surplus of the generated electricity falls into the external electrical networks. If the power is not enough for normal operation of household appliances, then it is fed from the outside.
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 a common network.
Network photovoltaic inverters with high efficiency use the energy obtained from solar panels. They are a guarantee of the stability of power supply and are distinguished by high efficiency exceeding 90%.
The hybrid or multipurpose inverter - the equipment reliable. It combines the properties of the first two converters, has a large number of settings. This is the best option for the device home solar station, but also the most expensive.
All existing solar inverters are divided into types and voltage output. Depending on this parameter, they are sinusoidal and meander. Since the first value of the output voltage is almost the same as that of the power supply network, this is a good option when there is a highly sensitive equipment in the house.
A constant voltage value is a guarantee of security for household electrical equipment. Graphically, the output waveform of such an inverter of a sinosuidal type is depicted as a pure sine wave.
When the equipment is in operation, the best form of the meander is the ideal sine. This is especially important for telecommunication equipment, medical equipment, high-precision measuring devices, therefore, even despite the price heights of complex inverters, there are no other options in this case. Information about the form of the output signal manufacturers indicate in its characteristics
Meander or non-sinusoidal transducers, unlike sinusoidal transducers, have a signal geometry at the output in the form of rectangular pulses called a modified sine. Inverters belonging to this type cannot be used for certain types of load, but for devices using the active power component, they are quite suitable.
Transducer Selection Criteria
When choosing such an element of the heliosystem as an inverter, not only the geometry of the output signal, but also its power is important. Experts advise staffing solar panels converters whose rated power is higher than the total power available in the equipment volume, by 25-30 percent.
It is also necessary to take into account the load arising from the simultaneous switching on of several devices with large starting power.
Another criterion when choosing an inverter is its efficiency, which determines the energy loss to related processes. Depending on the model, it has a different value, ranging from 85-95%. The optimal choice is efficiency not lower than 90%.
Inverters are both single-phase and three-phase. The former have a lower cost, but their choice is justified when the power consumption is less than 10 kW. The magnitude of the voltage is 220V, and the frequency is 50 Hz. Three-phase inverters have a wider voltage range - 315, 400, 690V.
Manufacturers of high-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, the following recommendations should be followed: if the power of solar cells does not exceed 5 kW, then a single inverter is enough for such a system. For higher capacity batteries, 2 or more inverters may be required. Optimally, when one inverter accounts for every 5 kW.
To work in a network that combines the use of standard electricity and energy supplied by solar panels, apply hybrid inverters. With features of the device and the rules of their choice will introduce the article recommended by us.
The transducers may differ from each other by the schemes, the geometry of the output signal, other determining values. Separate converters complete with chargers. If one of the inverters fails, the system will not stop its operation.
Features of the inverter connection
From the correct connection of the solar inverter depends on the efficiency of the entire solar system. The main thing is to follow the rule: a cable that transmits direct current must have a minimum allowable length and maximum cross-section.
If the consumer is far away from solar cells, the electric cable should be lengthened by building up, carrying an alternating current of 220 V. The length of the wire between the inverter and the solar panel should vary within 3 m and no more.
The best option when the inverter is located near solar battery. Particularly tough conditions have to perform when connecting inverters that exceed the power of 0.5 kW.
Wiring should be strong, because Insufficiently tight bonding causes arcing, which can be a source of fire. When installing an autonomous inverter to ensure uninterrupted power supply of the facility, the DC circuit must be equipped automatic switches.
The best solution when connecting an inverter is to use a hybrid type strapping in both direct and alternating current. The principle is based on a special procedure for switching on the converter. It includes solar controller after the batteries are charged.
This solution increases the quality of the equipment. In regions where electricity is often cut off, or in homes located in areas where cloudy weather prevails, this option works very efficiently.
Overview 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 capacity of 800 - 1200 W is produced by the Russian manufacturer MAP “Energy”.
The company produces several lines of inverters:
- Sine wave inverters with pure sine waveform - MAP SIN.
- Sinusoidal transducers with the function of selecting an additional amount of energy from the battery - MAP HYBRID.
- Three-phase inverters - MAP HYBRID 3 phase.
Inverters manufactured by this company can charge all types of batteries. For this they have Charger high power.
The company's achievement is the inverter of record power - 20 kW, which can withstand the greatest load of 25 kW. This model can provide reliable power to a large residential building with a variety of equipment.
MAP "Energy" inverters are used not only in private households, but also in many industries. They are used in medicine, construction, weather stations
Schneider Electric Conext Converters
The French company Schneider Electric produces inverters with high performance, allowing them to be used in different climates.
The hull coating with high corrosion resistance allows successful testing with salt fog. They are designed for solar panels installed on the roofs of private cottages and apartment buildings.
The manufacturer checks the reliability of its equipment using all sorts of techniques and tests. There are no electrochemical capacitors in the design of Conext inverters, which is a guarantee of 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 outdoor electrical panel
A large range of products allows you to choose a suitable model for solar systems with a capacity of 3 - 20 kW.
TBS Electronics Inverters
This Dutch company, which has been present on the market since 1996, produces both low-powered and more powerful sinusoidal converters for Poversine solar panels with a nominal power of 175 to 3500 watts.
In the photo is a model of a professional inverter Powersine PS3500-24. It can be used to provide uninterrupted power to heating boilers, pumps, computers, and other small loads. It is equipped with reliable electronics, high-strength metal housing.
The Powersine line is characterized by a very pure sinusoid at the output, therefore the use of these inverters ensures competent and long-term operation of highly sensitive devices. The equipment is equipped with protection against short circuit, temperature jumps, overloads. With these inverters you can run loads up to 500V with a starting force tens of times greater than the nominal one.
Network inverters Kostal
The company produces innovative high-quality inverters with a capacity from 1.5 to 20 kW, both single and three-phase. The design includes an AC switch that is automatically triggered, MPP trackers, a monitor, a S0 counter, and many other options as standard. All this makes it possible to introduce an inverter into the “smart home” system.
Kostal inverters are easy to use and install. Built-in panel - informative and understandable, allows you to monitor its work
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 conforms to European standards. Manufacturer's warranty - 5 years.
ABi-Solar Inverters from Taiwan
These inverters, released in Taiwan, are represented on our market by a series of autonomous converters SL / SLP, autonomous network-controlled hybrid inverters (NTR), a line of HT hybrids.
Autonomous converters are equipped with solar charge controllers. This equipment is endowed with a triple functional - it works as an inverter, controller, charger.
The design includes a liquid crystal display that allows you to control the main parameters of the heliosystem. The efficiency of SL / SLP inverters is about 93%. In the SLP models there is dust protection.
The budget option includes an inverter from the new ABi-Solar HTP series. It works only with a battery. The most popular is the NT series, which includes single and 3-phase hybrid inverters, which stand out for their excellent build quality.
Converters SL0912 and SL1524 also belong to the budget. They work in 2 modes - home-safe 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 by reducing their 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 capacity of 800 V. The output current has an unmodified sinusoid. It can be used for the sale of electricity produced by solar panels at a "green" tariff.
ABi-Solar inverters provide an opportunity to increase the operating temperature range batteries and automate the charge-discharge process.
Network inverters company GoodWE
This Chinese company produces network inverters of various capacities and supplies them to the market at a low price. A special program is attached to the inverter that allows you to perform a solar system calculation 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 an operating application specifically designed for this Android 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 question of connecting the inverter:
Photovoltaic network inverter, as an integral part of the solar system, allows you to get complete independence from the centralized power supply and the rise in prices for electronic media.
Smart systems, including a network converter, make the process of energy consumption accessible, reliable and manageable. At the same time comfort in the house is not broken in any way.
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