A wind generator is a device for converting wind energy into electrical energy, or into mechanical energy to drive mechanical devices (for example, a water pump). The ancestors of modern wind generators were windmills, and with the development of technology and the advent of the era of electricity, windmills no longer only ground grains into flour or pumped water, but also rotated generators that generated electrical energy.
Wind generators are industrial; such wind turbines are installed by the state or large energy corporations to provide electricity to industrial facilities. Industrial wind turbines are the largest and most powerful today, the power of individual wind generators amounts to megawatts, but such wind turbines are not installed one at a time, but huge wind farms are built in places where the wind is most suitable for stable generation of electricity, for example on the coasts, or on open hills . The energy from wind generators goes directly into the power grid, and the stability and rotation frequency of the generators is ensured by various mechanisms, for example, systems for adjusting the angles of the blades relative to the oncoming wind flow, so that the speed of the wind wheel, and therefore the generator, is stable.
There are also commercial wind generators that are installed for the purpose of selling electricity, or providing energy to various industries in those places where there is not enough own capacity, or there is no power grid at all. Such wind power stations also consist of many wind generators of varying power. The energy from such wind generators can be supplied directly to the electrical grid if they produce a stable alternating voltage of 220/380 volts or higher. Or wind generators are used to charge a large array of batteries, from which the energy is then converted into alternating voltage and supplied to the electrical grid.
There are also ordinary low-power household wind turbines for private use, the installation of which does not require any permits if the height of the mast does not exceed 25 meters and the wind generator does not interfere with aircraft. Such wind generators are low-voltage and their main task is to charge batteries with a voltage of 12/24/48 volts, and energy is taken from the batteries, which is converted into 220 volts 50 Hz as in a regular outlet. Low-power windmills are often installed to provide energy to private homes, summer cottages, farmsteads, or to power small remote facilities.
Design and design of wind generators
It is clear that wind generators are driven by wind energy, but that’s not all, a wind generator consists of several components and the main thing is a wind wheel and a generator. Horizontal wind turbines usually have three-bladed propellers, which operate due to the lifting force of the oncoming wind flow. And vertical wind generators of the Savonius type (barrel) rotate due to wind pressure. There are vertical wind turbines that also use lifting force, for example, the Darrieus Rotor and other orthogonal wind generators. For horizontal wind generators, the rotation speed of the blades exceeds the wind speed, usually nominally 5 times; this allows the use of smaller generators than for vertical wind generators, since they cannot rotate faster than the wind speed, with the exception of orthogonal ones.
For example, a wind generator with a wind wheel diameter of 3 meters at a wind speed of 10 m/s accounts for 5.6 kW of wind energy, but a maximum of 49% of the energy can be converted into mechanical rotational energy; for horizontal wind generators, the average wind energy conversion coefficient is 0.4, for vertical ones it is significantly lower, for wind turbines type "Savonius" 0.1-0.25, and for orthogonal ones up to 0.4.
The generator with the wind wheel can be connected directly and then the speed of the wind wheel and the generator will be the same, or a gearbox can be installed to increase the speed of the generator. In the designs of large wind generators, which are installed in places with a stable and powerful exhaust flow, a system for adjusting the position of the blades is used to maintain stable generator speeds. When the wind increases, the blades turn in one direction, increasing the angle of attack of the oncoming wind flow and the wind wheel does not gain momentum, and when the wind weakens, on the contrary, so that the windmill does not reduce the speed, the blades turn at higher speed. Also, the speed can be maintained by increasing or decreasing the load on the generator, or by the braking system. Thus, the generator operates at the same speed and produces a stable voltage and frequency of alternating current, for example 220 volts 50 Hz, although it can produce thousands of volts.
In small windmills, the generator speed is not stabilized as it is very difficult, and such windmills are installed at a low altitude in various areas where the wind may periodically disappear completely and be very unstable. To ensure stable operation, wind power stations use batteries; the generator charges the batteries when there is wind, and you can always take energy from them, even in complete calm. And to protect against hurricanes, they use a system that moves the wind wheel away from the wind by folding the tail, or they brake the wind wheel with an electric brake.
To charge the batteries, a controller is placed between the windmill and the battery, which monitors the charging of the battery, and when fully charged, so as not to spoil the batteries, the controller either slows down the propeller by short-circuiting the generator windings, or dumps excess energy into ballast, which can be used as heating tanks, or just a big resistor. A wind generator with a controller acts as a charger for the battery pack, and the energy itself is taken from the batteries, and not from the windmill.
But the batteries have a constant low voltage, which can be 12/24/48 volts, and to power the house you need 230 volts, so it is installed inverter, which converts direct voltage into alternating voltage 220 volts. But you can do without an inverter if all consumers are designed to be powered from low voltage. For example, if the battery array is 12 volt, then you can use any 12 volt electrical appliances, car chargers, TVs, 12 volt LED strips and light bulbs, car kettles, car refrigerators and much more.
wind generator, controller, batteries
Vertical windmills of the “Savonius” or “Barrel” type are the lowest-speed and inefficient windmills, so in order to achieve the same power as a horizontal one, such a windmill will have to be made much larger, install a very low-speed generator or multiplier, and Since it is not possible to lift such a heavy structure onto a high mast, the windmill should generally be twice as large in size as a horizontal one, and the generator should be five to seven times larger. This makes the cost of such wind generators increase five times compared to classic ones.
Therefore, windmills of the Savonius type are not popular and are quite rare, although they are quite popular on the Internet due to myths about their efficiency, noiselessness and simplicity. In fact, the KIEV of such wind turbines is only 0.1-0.2 versus 0.4 for classic wind turbines, noiselessness is also relative since in winds of 7 m/s everything makes noise, even trees. And about simplicity, it’s also a myth; it’s much easier to install three light and simple blades on a generator than to install a huge rotor, which cannot be protected from a hurricane, and therefore greater structural strength is needed. An example of such a homemade generator is described in this article - DIY vertical wind generator
Barrel type wind generatorThere are also other types of vertical wind generators, for example, the “Daria Rotor”, it has a slightly higher KIEV compared to a barrel-type wind turbine, but it has a very low starting torque, and if there are only two blades, then it cannot start on its own. - this is often done with a Savonius+Darieu hybrid rotor. There are other types with all sorts of curved blades, multi-story half-barrels, but in practice they are not far from the usual cut barrel.
Sailing wind turbines essentially the same horizontal windmills, but due to the fact that the entire wind wheel is covered with sails and there is no aerodynamic profile, such windmills are low-speed and ineffective, but they have high torque at low speeds and due to this they can directly drive various mechanisms, for example pump for lifting water. Analogues of a sailing windmill are multi-bladed windmills with rigid blades. Generators
Generators for windmills are the most common three-phase, similar to those used in cars, only depending on the power and rated speed, the dimensions will be much larger. The stator winding is three-phase, connected in a star circuit, after the connection, three wires remain at the output, which go to the controller, and there, with the help of a diode bridge, the alternating voltage is converted into direct voltage, that is, plus and minus. The generator rotor is based on neodymium magnets; electric excitation, as in auto-generators, is not used here since the excitation coil consumes energy.
To increase the speed, a multiplier is often used, which increases the speed and thus you can get either more power from the existing generator, or use a generator of smaller size and cost. Multipliers are often used in vertical wind generators because their wind wheel rotates much slower than that of horizontal classic wind turbines.
The generator is the most expensive part of a wind generator, except for the mast, which can be very expensive. Therefore, they try to make the speed of wind generators as high as possible in order to install smaller generators. This is actually why horizontal three-bladed wind generators have become so widespread. It has high speeds and does not require a multiplier to raise the generator speed; this makes the design much cheaper and simpler, and at the same time it has the highest efficiency.
You can make a generator yourself, and you can even make a complete wind generator yourself; on the pages of the site there is all the information on calculating generators and wind turbines in general. Generators are made from asynchronous motors, from auto-generators, and so-called axial disk generators are also very popular. You can read about windmills using such generators in this section Disc axial windmills
Wind turbine prices and applications
Wind generators are of course expensive, since they are complex equipment that is not widely used, such as televisions or cars. Also, in addition to the wind generator itself, the wind power plant contains batteries, a controller and an inverter, and the mast is also an expensive and integral part of the wind generator.
Wind generators with a power of 300 watts very weak and you need to understand that they produce their declared 300 watts per hour with a nominal wind of 10-12 m/s, and when the wind is 4-5 m/s, the output will be only 30-50 watt*h. Such windmills generate very little energy, which is enough, for example, to power small electronics and energy-saving LED lighting. You should not expect that such a windmill will be able to provide energy for a refrigerator, TV and light throughout the house. Energy production directly depends on the presence of wind at the location where the wind turbine is installed.
Let’s say, with an average annual wind speed of 3 m/s, the output of a 300 watt windmill will be only about 3-6 kW per month, but if the wind blows every day with an average speed of 5 m/s, then the output will be 15-20 kW, but such windy places exist not everywhere.
Prices for small wind turbines start at 15,000 rubles for a wind generator with a controller without batteries and a mast. A complete set consisting of a wind generator, controller, batteries, mast, inverter will cost from 50,000 rubles and more.
To provide energy for a small home or cottage a wind generator will need a power of 1 kW, energy production again depends on the presence of wind in your area, it can be 30-100 kW per month. In principle, such a wind generator is enough for lighting, a TV, a computer, a pump, but the wind generator may not be able to cope with the round-the-clock operation of a large refrigerator. In general, when a wind generator is installed to constantly provide energy to a residential area where energy is required every day, a gasoline or diesel generator is additionally installed, which charges the batteries during periods of prolonged absence of wind. A generator is a necessary device to ensure complete uninterruption of an autonomous wind power plant.
The cost of a complete set is from 150,000 rubles, and can reach up to 300-400 thousand rubles. The larger the battery capacity, the more time you can be powered from the battery in the absence of good wind. Also, batteries should not be deeply discharged, as this will greatly reduce their service life. Therefore, if, for example, 2 kW of energy is spent per day, then the energy in the batteries should be at least 10 kW.
If you plan to provide energy to your private home or small farm, then you will need a windmill with a power of 3-5 kW. The cost of a complete set is from 300,000 rubles to 1 million rubles. There is already serious power and consumption here, so in addition to the price of the windmill, the mast, controller, powerful inverter are also expensive, and you need a lot of batteries to stably provide energy to all household appliances.
If you want the wind generator to also heat the house, then you need to look at power from 10 kW. In general, for an autonomous power plant to be optimal in generating electricity, just one wind generator will not be enough. The system should have both solar panels and a gas generator in case there is no sun or wind at all. The controller must control both the wind generator and solar panels, and start the gas generator when the energy runs out. All this equipment is expensive, but if it is not possible to connect to the power grid, then the solution is to invest in a wind-solar power plant.
A wind-solar power plant provides electricity to all the needs of a private home, which is about 300 kWh per month. The system contains two wind generators with a total rated power of 3 kW, and solar panels with a rated power of 1.8 kW. The cost of this power plant was 350,000 rubles. Read more in the article
Wind energy amazes with the diversity and unusual design of wind generator designs. Existing designs of wind generators, as well as proposed projects, place wind energy out of competition in terms of originality of technical solutions compared to all other mini-energy complexes operating using renewable energy sources.
Currently, there are many different conceptual designs of wind generators, which can be divided into two main types based on the type of wind wheels (rotors, turbines, propellers). These are wind turbines with a horizontal axis of rotation (vane) and with a vertical axis (rotary, so-called H-shaped turbines).
Wind turbines with a horizontal axis of rotation. In windmills with a horizontal axis of rotation, the rotor shaft and generator are located at the top, and the system should be directed towards the wind. Small wind turbines are guided using wind vane systems, while larger (industrial) installations have wind sensors and servos that turn the axis of rotation into the wind. Most industrial wind turbines are equipped with gearboxes that allow the system to adjust to the current wind speed. Due to the fact that the mast creates turbulent flows behind it, the wind wheel is usually oriented in the direction against the air flow. The blades of the wind wheel are made strong enough to prevent them from coming into contact with the mast from strong gusts of wind. Wind turbines of this type do not require installation of additional wind orientation mechanisms.
A wind wheel can be made with a different number of blades: from single-bladed wind generators with counterweights to multi-bladed ones (with the number of blades up to 50 or more). Wind wheels with horizontal axis Rotations are sometimes performed in a fixed direction, i.e. they cannot rotate about a vertical axis perpendicular to the direction of the wind. This type of wind generator is used only when there is one dominant wind direction. In most cases, the system on which the wind wheel is attached (the so-called head) is rotary, oriented in the direction of the wind. Small wind generators use tail fins for this purpose, while large ones use electronics to control the orientation.
To limit the speed of rotation of the wind wheel at high wind speeds, a number of methods are used, including installing the blades in a feathered position, using valves that stand on the blades or rotate with them, etc. The blades can be directly fixed to the generator shaft, or a torque can be transmitted from its rim through the secondary shaft to a generator or other working machine.
Currently, the height of the mast of an industrial wind generator varies from 60 to 90 m. The wind wheel makes 10-20 turns per minute. Some systems have a switchable gearbox that allows the wind wheel to spin faster or slower depending on wind speed, while maintaining power generation. All modern wind generators are equipped with a system for possible automatic shutdown in case of too strong winds.
The main advantages of the horizontal axis are the following: variable pitch of turbine blades, allowing maximum use of wind energy depending on atmospheric conditions; a high mast allows you to “reach” stronger winds; high efficiency due to the direction of the wind wheel perpendicular to the wind.
At the same time, the horizontal axis has a number of disadvantages. Among them are high masts up to 90 m high and long blades that are difficult to transport, the massiveness of the mast, the need to direct the axis to the wind, etc.
Wind engines with a vertical axis of rotation. The main advantage of such a system is that there is no need to point the axis towards the wind, since the wind turbine uses wind coming from any direction. In addition, the design is simplified and gyroscopic loads are reduced, causing additional stress in the blades, gear system and other elements of installations with a horizontal axis of rotation. Such installations are especially effective in areas with variable winds. Vertical-axial turbines operate at low wind speeds and any wind direction without orientation to the wind, but have low efficiency.
The author of the idea of creating a turbine with a vertical axis of rotation (H-shaped turbine) is the French engineer George Jean Marie Darius (Jean Marie Darier). This type of wind generator was patented in 1931. Unlike horizontal-axis turbines, H-shaped turbines “capture” the wind as it changes direction without changing the position of the rotor itself. Therefore, wind generators of this type do not have a “tail” and look like a barrel. The rotor has a vertical axis of rotation and consists of two to four curved blades.
The blades form a spatial structure that rotates under the action of lifting forces arising on the blades from the wind flow. In the Daria rotor, the wind energy utilization coefficient reaches values of 0.300.35. Recently, development has been carried out on a Darrieus rotary engine with straight blades. Now the Darrieus wind generator can be considered as the main competitor of vane-type wind generators.
The installation has a fairly high efficiency, but it creates serious loads on the mast. The system also has a large starting torque, which is difficult to generate by wind. Most often this is done by external influence.
Savonius rotor
Another type of wind wheel is the Savonius rotor, created by the Finnish engineer Sigurt Savonius in 1922. Torque occurs when air flows around the rotor due to different resistance of the convex and concave parts of the rotor. The wheel is simple, but has a very low wind energy utilization factor - only 0.1-0.15.
The main advantage of vertical wind generators is that they do not need a wind orientation mechanism. Their generator and other mechanisms are located at a low height near the base. All this significantly simplifies the design. The working elements are located close to the ground, which makes them easier to maintain. Low minimum operating wind speed (2-2.5 m/s) produces less noise.
However, a serious drawback of these wind turbines is a significant change in the conditions of flow around the wing during one rotation of the rotor, which is repeated cyclically during operation. Due to rotation losses against the air flow, most wind turbines with a vertical axis of rotation are almost half as efficient as those with a horizontal axis.
The search for new solutions in wind energy continues, and there are already original inventions, for example, a turbosail. The wind generator is mounted in the form of a long vertical pipe 100 m high, in which, due to the temperature gradient between the ends of the pipe, a powerful air flow occurs. The electric generator itself, together with the turbine, is proposed to be installed in a pipe, as a result of which the air flow will ensure rotation of the turbine. As the practice of operating such wind generators shows, after spinning up the turbine and special heating of the air at the lower edge of the pipe, even in a quiet wind (and calm), a strong and stable air flow is established in the pipe. This makes such wind turbines promising, but only in uninhabited areas (when operating, such a plant sucks not only small objects, but also large animals into the pipe). These installations are surrounded by a special protective mesh, and the control system is located at a sufficient distance.
Experts are working on creating a special device for wind compaction - a diffuser (wind energy compactor). Over the course of a year, a wind turbine of this type manages to “catch” 4-5 times more energy than a conventional one. High rotation speed of the wind wheel is achieved using a diffuser. In its narrow part, the air flow is especially rapid, even with a relatively weak wind.
Wind generator with diffuser
As is known, wind speed increases with height, which creates more favorable conditions for the use of wind generators. Kites were invented in China approximately 2,300 years ago. The idea of using a kite to lift a wind generator to a height is gradually being realized.
Flying wind generator
Swiss designers from the company Etra presented a new design of inflatable kites that can lift up to 100 kg with a wing weight of 2.5 kg. They can be used for installation on marine vessels and lifting wind turbines to high altitudes (up to 4 km). In 2008, a similar system was tested during the voyage of the Beluga SkySails container ship from Germany to Venezuela (fuel savings amounted to over $1,000/day).
For example, in Hamburg, the Beluga Shipping company installed such a system on the diesel bulk carrier Beluga SkySails. A kite in the form of a paraglider measuring 160 m2 rises into the air to a height of up to 300 m due to the lifting force of the wind. The paraglider is divided into compartments into which, at the command of a computer, compressed air is supplied through elastic tubes. The Beluga SkySails company plans to equip about 400 cargo ships with such a system by 2013.
The design of the “Vetrolov” wind head has an interesting solution. The rotating housing of the generator is made quite long (about 0.5 m), in the middle part (in the interval from the generator flange to the blades) there is a mechanism for folding the blades. According to the principle of operation, it is similar to the opening mechanism of an automatic umbrella, and the blades resemble the wing of a hang glider. To ensure that the blades do not rest against each other during folding, their fastening axes are slightly offset. Four blades (through one) go inward, and four go outward. After folding, the windmill's drag area is reduced by almost four times, and its aerodynamic drag coefficient by almost two.
A “yoke” with a vertical axis of rotation is installed in the upper part of the windmill support. At one end there is a wind generator, at the other there is a counterweight. In light winds, the wind generator is raised above the upper level of the support by means of a counterweight, and the axis of the wind turbine is horizontal. As the wind increases, the pressure on the wind wheel increases and it begins to fall, turning around a horizontal axis. This is how another system of “escape” from strong wind works. The design allows the rocker arms to be extended so that the wind generators are installed one behind the other. It turns out to be a kind of garland of identical modules, which in weak winds stand one above the other, and in strong winds they go down, “hiding” in the “wind shadow” of the wind wheel. This also includes the system’s ability to adapt to external load.
Designers Marcos Madia, Sergio Oashi and Juan Manuel Pantano have developed the Eolic portable wind generator. Only aluminum and carbon fiber materials were used to manufacture the device. When assembled, the Eolic turbine has a length of about 170 cm. To bring the Eolic from folded into working condition, it will take 2-3 people and this process will take 15-20 minutes. This wind generator can be folded for carrying.
Today there are many design projects and developments. Thus, French designer Philippe Starck created the Revolution Air wind generator. The design windmill project is called “Democratic Ecology”.
An international group of designers and engineers Home-energy presented their product - the Energy Ball wind generator. The main feature of the new product is the arrangement of the blades on it like a sphere. All of them are connected to the rotor at both ends. When wind passes through them, it blows parallel to the rotor, which increases the efficiency of the generator. The Energy Ball can operate even at very low wind speeds and produces much less noise than conventional wind turbines.
A unique wind turbine was created by designers from Samara. When used in an urban environment, it is cheaper, more economical and more powerful than its European counterparts. The Tretyakov wind generator is an air intake that captures even relatively weak air flows. The new product begins to generate useful energy already at a speed of 1.4 m/s. In addition, no expensive installation is needed: the installation can be installed on a building, mast, bridge, etc. It has a height of 1 m and a length of 1.4 m. The efficiency is constant - about 52%. The power of the industrial device is 5 kW. At a distance of 2 m, the noise from the wind farm is less than 20 dB (for comparison: fan noise is from 30 to 50 dB).
The American company Wind Tronics from Michigan has developed a compact wind turbine for use in private households. The technology developer is Wind Tronics, and manufacturing giant Honeywell has started manufacturing wind turbines. The design includes zero damage to the environment.
This installation uses a Blade Tip Power System (BTPS) turbine impeller, which allows the wind generator to operate over a much wider range of wind speeds, while also reducing mechanical drag and turbine weight. Wind Tronics starts rotating at a wind speed of only 0.45 m/s and is operational up to a speed of 20.1 m/s! Calculations show that such a turbine generates electricity on average 50% more often and longer than traditional wind generators. By the way, the automation with an anemometer constantly connected to it monitors the speed and direction of the wind. When the maximum operating speed is reached, the turbine simply turns to the wind with a streamlined side. The system's automation immediately responds to freezing rain that can cause icing. The technology has already been patented in more than 120 countries.
Interest in small wind turbines is growing around the world. Many of the companies working to solve this problem have been quite successful in creating their own original solutions.
The Optiwind company produces original wind turbines Optiwind 300 (300 kW, cost - 75 thousand euros) and Optiwind 150 (150 kW, cost - 35 thousand euros). They are designed for collective energy savings in villages and farms (Fig. 12). The main idea is to collect wind energy using stacked structures of several turbines at a decent height. The Optiwind 300 is equipped with a 61-meter tower, the accelerator platform is 13 m in diameter, and the diameter of each turbine is 6.5 m.
The design of the GEDAYC turbine has an unusual appearance (Fig. 13). The low weight allows the turbine to effectively rotate the electric generator at a wind speed of 6 m/s. The new blade design uses a principle similar to the "system" of a kite. GEDAYC turbines have already been installed on three 500 kW wind turbines that supply energy to the mines. The installation of GEDAYC turbines and their trial operation have shown that thanks to the new design, the turbines are lighter, more convenient to transport and easier to maintain.
Earth Tronics has developed a new type of “home” wind turbines from Honeywell. The system makes it possible to generate electricity at the tips of the blades, and not at the axis (as is known, the speed of rotation of the tips of the blades is much higher than the speed of rotation of the axis). Thus, the Honeywell turbine does not use a gearbox and generator, as in conventional wind generators, which simplifies the design, reduces its weight and the wind speed threshold at which the wind generator begins to produce electricity.
A pilot project of a wind generator with magnetic levitation has been created in China. The magnetic suspension made it possible to reduce the starting wind speed to 1.5 m/s and, accordingly, increase the total output of the generator during the year by 20%, which should reduce the cost of generated electricity.
Arizona-based Maglev Wind Turbine Technologies intends to produce Maglev Turbine vertical axis wind turbines with a maximum capacity of 1 GW. This exotic wind turbine model looks like a high-rise building, but is small in relation to its power. One Maglev turbine can provide energy to 750 thousand homes and covers an area (including the exclusion zone) of about 40 hectares. This turbine was invented by inventor Ed Mazur, founder of MWTT. The Maglev Turbine floats on a magnetic levitation. The main components of the new installation are located at ground level, making them easier to maintain. In theory, the new turbine works normally both in extremely weak winds and in very strong ones (over 40 m/s). The company intends to open scientific and educational centers near its turbines.
When studying the creative heritage of the brilliant Russian engineer Vladimir Shukhov (1853-1939), specialists from Inbitek-TI LLC drew attention to his ideas of using steel rod hyperboloids in architecture and construction.
The potential of such structures today has not been fully studied or explored. It is also known that Shukhov called his work with hyperboloids “research”. Based on his ideas, the development of rotor-type wind generators of a completely new design emerged. This design will make it possible to generate electricity even at very low wind speeds. To start from rest, a wind speed of 1.4 m/s is required. This is achieved by using the levitation effect of the wind generator rotor. A wind generator of this type is able to start working even in rising air currents, which usually occurs next to a river, lake, or swamp.
Another interesting project - the Mobile Wind Turbine wind generator - was developed by the designers of the Pope Design studio (Fig. 17). This is a mobile wind generator located on the base of a truck. To operate the Mobile Wind Turbine, only an operator-driver is needed. This wind generator can be used in natural disaster zones, during emergency response, and when restoring infrastructure.
CONCLUSION
The current state of wind energy, the proposed designs and technical solutions of wind generators and “wind compactors” make it possible to create mini-wind power plants for private use almost everywhere. The speed threshold for starting a wind generator has been significantly reduced thanks to technical developments; the weight and size indicators of wind turbines are also decreasing. This makes it possible to operate wind power plants in “home” conditions.
Svetlana KONSTANTINOVA, Candidate of Technical Sciences, Associate Professor BNTU
A modern kinetic wind generator allows you to take advantage of the power of air currents, converting it into electricity. For this purpose, there are factory-made and home-made models of devices that are used both in industry and in private households.
We will tell you how wind turbines of this type are designed, and introduce you to the features of the device and design options. The article we have proposed shows the strengths and weaknesses of a wind power plant. Do-it-yourselfers will find useful diagrams and assembly recommendations here.
The operation of a wind generator is based on the transformation of the kinetic energy of the wind into the mechanical energy of the rotor, which is then converted into electricity.
The principle of operation is quite simple: the rotation of the blades fixed to the axis of the device leads to circular movements of the rotor generator, thereby generating electricity.
Wind energy is one of the most promising sectors of renewable energy. Modern designs make it possible to cost-effectively harness the power of air currents, using it to generate electricity
The resulting unstable alternating current “drains” into the controller, where it is converted into direct voltage that can charge the batteries. From there, the power is supplied to the inverter, where it is transformed into an alternating voltage with an indicator of 220/380 V, which is supplied to consumers.
The power of a wind generator directly depends on the power of the air flow (N), calculated according to the formula N=pSV 3 /2, where V is the wind speed, S is the working area, p is the air density.
Various versions of wind generators differ significantly from each other.
The diagram below shows the internal structure of a classic horizontal wind generator. Such models are most often used both in industry and in everyday life.
Industrial devices are a complex multi-meter structure, the installation of which requires a foundation, while a household model can consist of a minimum of components (DC electric motor 3-12V, electric capacitor 1000 uF 6V, silicon rectifier diode).
A typical installation includes the following components:
To better meet user needs, the device can be equipped with various types of inverters:
When choosing models, be sure to pay attention to the type of inverter.
When classifying wind turbines, the following characteristics can be taken into account:
Let's take a closer look at the two most commonly used classifications.
There are types of wind turbines that differ in purpose. The main characteristics of devices, for example, power, depend on this.
Such devices are installed by large energy companies or the state to supply electricity to industrial facilities. Turbines, with a capacity of tens of megawatts, are usually located in wind areas (open hills, coasts).
Wind farms, where dozens of wind turbines are installed, are located not only on land, but also in shallow water. The resulting electricity is usually used for industrial purposes
The generated electricity, as a rule, goes directly into the network, while for stability and regulation of the speed of rotation of the blades, wind turbines are equipped with additional mechanisms.
Such installations are used to generate electricity for sale or to provide electricity to production in regions with a low-power electrical network (or no electricity grid at all). Such wind power plants consist of a cluster of electric generators, which can have different capacities.
Energy from commercial installations can be fed directly into electrical utilities or used to charge a large array of batteries, where it is stored and converted to feed the grid.
Low power units are used for private use. According to the rules, wind turbines with masts less than 25 meters high can be installed by land owners without approval from the authorities; for higher masts, special permission must be obtained.
Windmills of low and medium power can serve as a source of electrical energy for cottages, dachas, country houses, and farms
Household wind generators are suitable for charging batteries with a voltage of 12/24/48V, the energy from which is transformed into a voltage of 220 Volts. Such devices make it possible to completely or partially solve the problem of power supply to small objects that are located far from the centralized power grid.
With guidelines for choosing a wind generator to provide energy to a private home, dedicated to this interesting issue.
Based on their design features, devices can also be divided into a number of categories, although all varieties come down to two main types: horizontal.
Such installations (they are also called propeller or wing) usually have 3-5 blades mounted on a horizontal axis. Rotating at high speed, such elements allow you to obtain the maximum amount of energy (KIEV up to 0.4).
Moreover, the amount of electricity generated largely depends on the height of the device (the higher it is, the greater the result).
A horizontal wind turbine uses lift, which occurs when pressure increases at the point where direct air flow passes through the blades and is reflected from these elements.
These devices are typically installed in wind farms where energy is generated for industrial and commercial use, but they are also suitable for domestic use.
The operating element of such installations is a rotating wind wheel. Due to their design features, such structures differ by type (“Barrel”, “Savonius”).
Despite the low KIEV index (0.1-0.2), they are widely used: vertical installations operate on turbulent air flows, so they can be placed even in areas where strong winds rarely blow.
The operation of vertical wind generators does not depend on the direction of the winds. They are easy to install and operate, and such devices can be installed close to the ground
To improve the efficiency of vertical wind turbines, manufacturers often increase their dimensional parameters, which leads to a significant increase in cost. Since such installations are quite fragile, they require increased protection from hurricanes and other natural phenomena.
Such devices belong to the category of vertical wind turbines, but have pronounced differences in design. Thanks to such features, noise reduction is achieved, and KIEV also increases, which approaches the performance of horizontal models.
A low-pressure turbine with an axis of rotation perpendicular to the air, proposed in 1931 by the French aircraft designer Georges Darrieus, has found wide application in wind energy.
The disadvantage of such designs is the low starting torque (due to the presence of only two blades, it is difficult for the device to start on its own). To solve the problem, the “Savonius + Darier” hybrid is often used.
For such installations, the principle of constructing both vertical and horizontal wind turbines can be used. The main design feature is a wind wheel covered with many blades or sails, while such models do not have an aerodynamic profile.
There are many models of sailing wind generators, which differ in the number of blades, weight, and power. All these parameters should be taken into account when choosing a device
Despite the fact that sailing installations are characterized by low speed and low efficiency, they are often used in the national economy. Such designs are easy to install and operate, and the combination of high torque and low speed allows you to directly drive various useful mechanisms, for example, a pump for pumping out water.
Wind turbines require conventional three-phase generators to operate. The design of such devices is similar to models used on cars, but has larger parameters.
Wind turbine instruments have a three-phase stator winding (star connection), from which three wires come out and go to the controller, where the alternating voltage is converted to direct voltage.
The generator rotor for a wind turbine is made of neodymium magnets: in such designs it is inappropriate to use electrical excitation, since the coil consumes a lot of energy
A multiplier is often used to increase turnover. This device allows you to increase the power of the existing generator or use a smaller device, which reduces the cost of installation.
Multipliers are more often used in vertical wind generators, in which the process of rotating the wind wheel is slower. For horizontal devices with high blade rotation speeds, multipliers are not required, which simplifies and reduces the cost of the design.
The specifics of the assembly and installation of a wind generator and wind turbine are described in detail in the articles we recommend.
Let us consider in detail the advantages and disadvantages of wind turbines, since the decision to purchase a wind turbine or abandon it depends on them.
The advantages of devices using wind energy include:
The use of wind turbines can be an alternative to the use of expensive diesel generators, further reducing the costs of transportation and storage of fuel by up to 80%.
The average power of a wind turbine differs several times from the peak load. A wind generator is responsible only for the amount of energy produced over a certain period of time at the average monthly wind speed characteristic of a given area.
For a more accurate assessment of wind resources, you can use specially derived data (Weibull parameters). These indicators reflect the distribution of winds of different strengths characteristic of a particular area. It is important to take such information into account when developing wind farm projects with a capacity of tens of MW.
The power generated by a wind turbine is proportional to triple the wind speed. Consequently, this indicator is very small when wind flows are weak, but when they intensify, it increases sharply. Due to the variability of wind direction and speed, stabilizing components must be included in the design of a wind turbine.
Rules and formulas for calculating the power of a wind generator, we recommend that you familiarize yourself with the very useful information.
In small autonomous systems, their function is performed by batteries, the charge of which begins to increase as soon as the power of the wind generator exceeds the load.
As the load increases, the battery may discharge. It is important to take this feature into account when choosing a household unit; its power must match the monthly or annual electricity consumption rate
It should be noted that the effective use of wind flows is facilitated by a variety of wind generator designs.
Horizontal turbines perform well in flat areas where there is a lot of wind, while vertical turbines work better in regions with turbulent flows found low to the ground (upper hills, mountain ranges).
At the same time, wind turbines also have their negative sides:
Negative aspects can also include the rather high cost of such units, however, the low cost of the energy source largely offsets this factor.
Although a wind turbine can operate autonomously, much better results can be achieved using combined schemes that combine a wind turbine with solar panels, a centralized power grid, diesel or gas energy sources.
Autonomous operation. In this case, a single installation is installed, with the help of which wind energy is captured and accumulated, which is then converted into the electric current needed by consumers.
The diagram shows the simplest way to use a wind generator, which is advisable to use in regions where strong winds constantly blow
Combining a wind generator with solar panels. The combined option is considered a reliable and efficient method of power supply. In the absence of wind, the battery operates from, and in cloudy weather and during the night, charging occurs from a wind turbine.
An ideal option for a private home or farm located far from a centralized power grid. This combined scheme allows the use of two types of renewable energy
Combined operation of a wind generator and power grid. A wind turbine can be combined with electrical communications.
This arrangement is typical for industrial and commercial devices. Connection to electrical communications is also provided for some models of household wind generators
If there is an excess of electricity produced, it goes to the centralized network, and if there is a shortage, it is possible to use electric current from the general energy system.
Currently, wind turbines are used in various sectors of the national economy. Industrial models of varying capacities are used by oil and gas, telecommunications companies, drilling and geological exploration stations, production facilities and government agencies.
The wind turbine can be used as an additional source of energy in hospitals and other institutions to ensure continuous power supply in emergency situations
Particularly noteworthy is the importance of using wind turbines for the prompt restoration of damaged electricity during cataclysms and natural disasters. For this purpose, wind generators are often used by units of the Ministry of Emergency Situations.
Household wind turbines are perfect for organizing lighting and heating in cottage communities and private houses, as well as for economic purposes on farms.
There are some points to consider:
When choosing a model, you should take into account that the power indicator indicated on the device is achieved only at maximum wind speed. Thus, a 300V installation will produce the specified amount of energy only at an air flow speed of 10-12 m/s.
For those wishing to build a wind generator with their own hands, we offer it, which contains useful information in detail.
The video below provides detailed information about the operating principle and design of a household model of a wind generator:
A wind generator is an excellent source of electrical energy production, which will be especially appreciated by residents of remote areas. Various Russian and foreign enterprises offer a wide range of wind structures; in addition, household models can be made with your own hands.
Please write comments in the block below. Tell us about how you built a wind generator on your property, or about how your neighbors’ wind turbine works. Ask questions, share useful information and photos on the topic.
The article contains information about wind generators, what they are needed for, their types, advantages and disadvantages.
Specific classifications of design types and operating principles of a wind power plant are also given.
Wind generators are an economical invention that allows you to generate electricity from the wind.
Wind generators can be:
Multi-lobed ones react very sensitively to the slightest breath of air, but do not produce much energy. They are well suited for pumping out water.
Based on the type of material used, wind generators are divided into:
Specialist's note: Rigid wind generators are much more reliable than sailing ones, but are more expensive.
The difference between the step principle is that some generators have a constant step, while others have a variable step.
The fixed pitch is distinguished by its reliability, while the variable pitch quickly gains momentum, but has a complex, impractical design.
According to the placement of the axis, wind generators exist:
Helpful information: Horizontal wind generators are distinguished by their power, while vertical ones capture the wind well.
They are used to convert wind force into counterforce or lifting energy.
Lifting energy develops greater force than counteracting energy. The latter cannot gain speed above the wind speed.
Generators that resemble a wheel are also made with a horizontal center. They are made both stationary relative to the vertical and with a diversified direction of movement.
When there is a strong wind flow, a limit on wheel rotation is set. In such cases, the wings set the wheel to rotate differently, use valves to regulate flow, or use devices to move the wheel out of the wind. The wings are mounted both on the generator axis and on the rotating rim of the secondary shaft.
Vertical rotary generators differ from horizontal ones in many advantages:
These devices have plates, turbine components, Savonius rotors with S-shaped ends in a "carousel" type.
In 1920, the Frenchman Georges Darrieus developed a new rotor. Thus, Darrieus declared himself as the main developer of wind generators with wings. These generators are powered by the force generated by the curved wings.
The rotor is very agile, fast, and can have different shapes, both diamond-shaped and triangle-shaped. Available with either one or multiple wings.
The wings are made primarily of wood, but sometimes also of steel. This is done for their agility and ease of operation.
The electricity generated directly depends on the wind power and the width of the wings.
Accordingly, by increasing the size of the wings, the electrical output can be increased.
There are small and medium-sized turbines. Medium ones are easy to use and easy to produce.
At the moment, even the most powerful wind generators, alas, are not capable of supplying large cities with electricity. Wind generators with low power are used for farming needs, they provide water supply, which is a very economical way.
Wind farms are a network of many wind generators that convert wind energy into electricity.
It includes:
They work as follows: the wind, coming into contact with the wings of the wind generator, sets them in motion, the mechanisms of the electric generator are started, which leads to the generation of electricity.
Various types of designs are used for power plants:
A wind power plant is a very economical way to generate electricity, but due to their low power and direct dependence on weather conditions, they are not the main source of electricity.
They can impede the natural flow of air and insignificantly change the climate. The construction of a power plant takes up huge areas compared to other power generators.
On the one hand, wind generators are a natural source of electricity; their operation does not pose any harm to humans and is an excellent endless reserve.
They are varied and you can choose the best one for your needs.
Wind generators are often installed on farms and their own plots. But, on the other hand, they depend on weather conditions, wind flow, and can cause inconvenience in the form of noise from work. Also, large power plants can interfere with radio waves and airborne messages.
In addition, huge power plants impede the migration of birds. The generated power, even from the largest stations, is still not enough to provide electricity to large cities.
Watch the video, which discusses the operating features, as well as the advantages and disadvantages of wind generators:
To begin with, let's agree that when we talk about wind turbines, we mean that part of the wind power unit (APU) that converts wind energy into the energy of rotational motion. A wind turbine is driven by the wind and is connected directly or through some transmission mechanism to a shaft, the rotation of which drives equipment that performs useful work (for example, a generator or a water pump). A wind turbine is often called a rotor or a wind wheel.
In this post we will talk about the main types of wind turbines. It is not easy for an amateur who is encountering wind energy for the first time to make the right choice from the many types of such installations.
First of all, you need to clearly know what you need, what desired power you expect to receive from your installation, what the weather conditions of the area are, and after all, move on to a detailed acquaintance with this or that type of wind turbine. And different types of wind generators produce completely different results of their work. In this publication, you will learn what types of wind generators exist today, and after getting to know them, it will not be difficult for you to make the right choice.
For modest appetites, a suitable choice would be the so-called orthogonal wind generator, which can be suitable for use in areas where there are very weak breezes. It has several blades parallel to the axis, located at some distance from it. (see photo).
So, wind generators differ in type by:
Depending on the number of blades, they can be one, two, three or multi-bladed. The latter begin their rotation at the slightest air movement, but are applicable only for purposes where the fact of rotation itself is important, and not the generated electricity. That is, they are indispensable, say, when pumping water from deep wells.
Based on the materials from which the blades are made, a distinction is made between rigid and sail wind generators. Sailing ones are much cheaper than rigid ones made of fiberglass or metal, but during operation you can get tired of repairing them.
Based on the location of the rotation axis to the soil surface, a distinction is made between horizontal and vertical wind generators. Their differences are so delicate that under different conditions they change places in their superiority. Windmills with a vertical axis immediately capture the slightest breeze and do not require a weather vane, but they are less powerful than horizontal ones.
Based on the propeller pitch, wind generators come with variable and fixed pitch. The variable pitch undoubtedly makes it possible to increase the rotation speed, but what a design! It is complex, increases the weight of the windmill, that is, it will require incalculable extra costs. A fixed step is much simpler and more reliable.
This, in a nutshell, is your compass so as not to get lost in your choice.
It is also necessary to provide a list of some terms and abbreviations that will be used in the future.
As already noted, there are still two types of wind generators on sale (based on the location of the rotation shaft to the surface of the earth) - horizontal and vertical. Let's talk about vertical ones first.
Wind power units (APU) with a vertical axis of rotation have an undeniable advantage for everyday life: their components that require maintenance are concentrated at the bottom and no lifting is required. There remains, and even then not always, a thrust-support self-aligning bearing, but it is strong and durable. Therefore, when designing a simple wind generator, the selection of options should begin with verticals.
In the first position is the simplest one, most often called the Savonius rotor.
At the beginning of October 1924, Russian inventors brothers Ya. A. and A. A. Voronin received a Soviet patent for a transverse rotor turbine; the following year, Finnish industrialist Sigurd Savonius organized mass production of similar turbines. The glory of the inventor of this new product remains with us.
The Voronin-Savonius rotor, or BC for short, is at least two half-cylinders on a vertical axis of rotation (see photo). And no matter what direction the wind is, no matter how sharply it changes its gusts, such a windmill will calmly rotate around its axis, generating energy. This is the only and main advantage of a vertical windmill over a horizontal one.
And its main drawback is the low use of wind energy. This is explained by the fact that the semi-cylinder blades operate only a quarter of a revolution, and for the rest of the rotation circle they seem to slow down the rotation speed with their movement. Calculations have shown that only a third of the wind energy is used.
Note: the two-blade aircraft does not spin, but jerks jerkily; The 4-blade is only slightly smoother, but loses a lot in KIEV. To improve, 4-trough blades are most often divided into two floors - a pair of blades below, and another pair, rotated 90 degrees horizontally, above them. KIEV is preserved, and the lateral loads on the mechanics weaken, but the bending loads increase somewhat, and with a wind of more than 25 m/s such an APU is on the shaft, i.e. without a bearing stretched by cables above the rotor, it “tears down the tower.”
In 1931, the French designer George Darrieus proposed his own version of the rotor, which has two or more flat blades. It is even simpler than the BC: the blades are made of a simple elastic tape without any profile. Easy to manufacture and install, but with low efficiency - KIEV - up to 20%.
The theory of the Darrieus rotor is not yet sufficiently developed. It is only clear that it begins to unwind due to the difference in the aerodynamic resistance of the hump and the tape pocket, and then it becomes sort of high-speed, forming its own circulation. The torque is small, and in the starting positions of the rotor parallel and perpendicular to the wind it is completely absent, so self-spin is possible only with an odd number of blades (wings?) In any case, the load from the generator must be disconnected during spin-up.
The Daria rotor has two more bad qualities. Firstly, when rotating, the thrust vector of the blade describes a full rotation relative to its aerodynamic focus, and not smoothly, but jerkily. Therefore, the Darrieus rotor quickly breaks down its mechanics even in a steady wind. Secondly, Daria not only makes noise, but screams and squeals, to the point that the tape breaks. This happens due to its vibration. And the more blades, the stronger the roar. So, if they make a Daria, it is with two blades, from expensive high-strength sound-absorbing materials (carbon, mylar), and a small aircraft is used for spinning in the middle of the mast-pole.
Another type of wind generator with a vertical axis of rotation - with helicoid rotor. It is able to rotate evenly due to the twisting of the blades. Advantage: reduces bearing load and increases service life. But due to the complex technology it is too expensive. (See picture).
And finally, there are wind generators with multi-blade rotor. This is one of the most efficient types of vertical wind generators. (See picture).
Let's move on to the description of horizontal wind generators. Based on the number of blades, they are divided into one, two, three and multi-blade. The advantages of horizontal ones are higher efficiency compared to their vertical rivals. Disadvantage: the need to install a weather vane to constantly search for the direction of the wind. In addition, when turning towards the wind, the rotation speed decreases, which reduces its efficiency.
The main advantage of single-blade ones is their high rotation speeds. Instead of a second blade, they have a counterweight installed, which has little effect on the resistance to air movement, which makes it possible to use them for generators with high rotation speeds. And this allows you to reduce the weight and dimensions of the entire installation. (See picture of a single-blade wind turbine).
Two-blade wind turbines differ little in power from single-blade wind turbines and it makes no sense to consider them in more detail.
Three-bladed horizontal windmills are the most common in sales markets. Their output power can reach seven megawatts.
Multi-blade installations with a number of blades up to five dozen have high inertia, due to which they develop high torque at low rotation speeds. This advantage allows the installations to be used for operating water pumps, where they occupy a leading position.
Who doesn’t know that wind turbines are used as an additional source? Everyone is aware. But as always, this was not enough for humanity; they are trying to turn a chicken into an ostrich and, imagine, figuratively speaking, this succeeds. As a result of tireless research, completely new types of wind generators have emerged that are capable of producing electricity... without blades. And there are those who even manage without air and wind! Now in more detail.
A fairly effective wind generator has already been released, which catches the wind without blades. This wind generator operates on the principle of a sailboat (see photo). The “sail,” which rather looks like a plate, catches the air pressure, due to which the pistons, which are located immediately behind the plate, in the upper part of the installation, begin to move.
The pistons drive the hydraulic system, which generates electricity. Such a structure has no gears or transmitters and makes almost no noise. The efficiency is much higher than that of a classic wind generator. Among other things, operating costs are half lower than conventional installations. The country of birth of such a project is Tunisia.
But this turned out to be not enough! In Portugal, they decided not to resort to wind services, but to use sea water. After all, the sea is constantly moving, agitated, sometimes stormy, but never stops. It is obvious that kinetic energy is wasted.
And five years ago, a few kilometers from the coast, an installation was launched onto the waters of the Atlantic Ocean, which produces more than 2 megawatts of electricity, which is enough to illuminate more than one and a half thousand houses.
The schematic structure is as follows. The structure consists of three sections, between which there are pistons. Hydraulic motors and generators are mounted inside the sections. The operating principle is incredibly simple. The sections swing on waves that bend them, which sets hydraulic pistons in motion. They put pressure on the oil, it enters the hydraulic motors and then the movement is transmitted to the generators. That's it, the electricity has gone ashore.
Three sections are currently operating, they plan to connect another 25 such converters to them, and then the design capacity of the offshore installation will increase to 20 megawatts, which will make it possible to supply about 15,000 homes with current.
Now you believe that you can create a real ostrich from a chicken!
Float power plants are being constructed all over the world, including in Russia:
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