Kinetic wind generator: device, principle of operation, application

Wind turbine device

Wind generators are absolutely environmentally friendly and are able to provide consumers with free energy for an unlimited time. Wind generators - wind farms have different capacities, which makes it possible to use them in different areas.

The maximum efficiency of a wind farm can be achieved by installing it in places with constant active air currents. Usually, mountains and hills, coasts of the seas and oceans, and other similar conditions are used for this. The main part of the installation is the impeller, which acts as a turbine. In most cases, three-blade wind farm structures are used in the form of a propeller, installed at a high altitude from the earth's surface.
In order to get the greatest effect, the blades, together with the rotor, are set to the optimal position using special mechanisms, depending on the direction and strength of the wind. There are other designs - drum, which do not depend on the above factors and do not require any adjustments. However, if the efficiency of propeller installations is at the level of 50%, then for drum devices it is much lower.

Each air power plant, regardless of design, is completely connected with the action of air currents, which often change their performance. This in turn leads to changes in the number of revolutions of the impeller and the electrical power produced. This situation requires pairing the generator and the electrical network with the help of additional equipment.

As a rule, batteries are used for this together with inverters. First, the battery is charged from the generator, for which the uniformity of the current does not matter. Further, the battery charge, converted in the inverter, is transferred to the network.

WPP propeller structures can be controlled if necessary. If the wind speed is too high, the angle of attack of the blades is changed, up to the very minimum.This leads to a reduction in the wind load on the turbine. However, under the influence of hurricanes, the impellers of wind farms are often deformed, and the entire home installation fails. It is not possible to completely avoid negative impacts, since electric generators are located at an average height of 50 m. Due to this, it is possible to use stronger and more stable winds prevailing at high altitudes.

How to choose a wind generator

In order to choose a wind generator, you must:

1. Calculate the installed power of electrical appliances that are planned to be connected to this energy source.
2. Based on the obtained values ​​of power and the average annual wind speed, in the region of installation of the unit, the power of the generator is determined. Power should be taken taking into account the safety factor, based on the growth of loads and so as not to overload the device during peak loads.
3. Consideration should be given to the climate in the place where the device is installed, since precipitation adversely affects the performance of the generator. Take into account the climatic features of the place of residence.
4. Determining the efficiency of the installation is one of the most important indicators.
5. Find out the performance of the generator in relation to the noise produced during operation.
6. Conduct a comparative analysis of various types of generators for all characteristics and parameters.
7. Read user reviews of similar installations.
8. Make an analysis of domestic and foreign manufacturers, study reviews about these enterprises.

Placement of a low-speed wind generator

A small foundation is placed in a piece of land, in which the mast is fixed. Near the tower, at the foot, there is a power cabinet.At the top, a rotary mechanism is installed, a gondola is mounted on it. Inside the latter are an anemometer, generator, transmission and brakes. A rotor cap is attached to the gondola, into which the blades are stuck. Each wing is connected to a system that automatically adjusts the pitch.

Installation of a low-speed wind turbine begins with the foundation and installation of the mast

After completing the installation of the generator, they mount systems for lightning protection and transmission of information about work, as well as a fairing and a fire extinguishing mechanism.

A low-speed wind generator is a device that can provide electricity to a suburban area. Use is justified in areas with light wind.

Specifications

At the time of buying wind turbine charge controller you need to carefully study his data sheet. When choosing, the characteristics are important:

• power - must correspond to the power of the wind turbine;
• voltage - must correspond to the voltage of the batteries installed on the windmill;
• Max. power - indicates the maximum allowable power for the controller model;
• Max. current - indicates with what maximum powers of the wind generator the controller can work;
• voltage range - indicators max. and min. battery voltage for adequate operation of the device;
• display capabilities - what data about the device and its operation are displayed on the display of a particular model;
• operating conditions - at what temperatures, humidity level the selected device can operate.

If you cannot choose a charge control device yourself, contact a consultant and show him the data sheet of your windmill. The device is selected in accordance with the capabilities of the wind installation.Incorrect operating conditions and deviations from the voltage range will adversely affect the operation of the entire wind system.

Wind Turbine Generator

For the operation of windmills, conventional three-phase generators are required. The design of such devices is similar to the models used on cars, but has larger parameters.

Wind turbine devices have a three-phase stator winding (star connection), from which three wires exit, going to the controller, where the AC voltage is transformed into DC.

The generator rotor for a wind turbine is made on neodymium magnets: in such designs it is not advisable to use electrical excitation, since the coil consumes a lot of energy

To increase the speed, a multiplier is often used. Such a 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 turbines, in which the process of rotation of the wind wheel is slower. For horizontal devices with a high speed of rotation of the blades, multipliers are not required, which simplifies and reduces the cost of construction.

How to make a wind generator calculation yourself

Formulas are used to calculate the power parameter of equipment that will be used in a particular area. First of all, a calculation is made of the amount of energy that allows the wind generator to generate throughout the year.

Calculation of the total power of the equipment

To complete the task, the following actions are performed:

1. First, the calculations are made.In accordance with the results obtained, the length of the elements of rotation, as well as the height of the tower, are selected.
2. An analysis of the average speed of the air flow characteristic of a particular area is performed. This will require special equipment. With it, you need to monitor the strength of the air flow for several months. If there is no instrument, you can request the results from representatives of the local weather station.

Power calculation wind generator is performed according to the formula P=krV 3S/2.

Symbol designations:

• r is the air flow density parameter, under normal conditions this value is 1.225 kg/m3;
• V is the average wind speed, measured in meters per second;
• S is the total area of ​​the air flow, measured in meters;
• k is the efficiency parameter of the turbine installed in the equipment;

Using these calculations, you can accurately determine the amount of power required for a generator set in a particular area. If branded equipment is purchased, then its packaging should indicate at what force of air flow the operation of the device will be most efficient. On average, this value will be in the range from seven to eleven meters per second.

The user Odessa engineer spoke in detail about the procedure for assembling the generator device, as well as about performing calculations.

Calculation of propellers for a wind turbine

The calculation procedure is performed according to the formula Z=LW/60/V, symbol notation:

• Z is the low-speed value of one propeller;
• L is the size of the circle that the rotation elements will describe;
• W is the speed of turning one screw;
• V is the speed parameter of the air flow supply.

Based on this formula, the number of revolutions is calculated. But for the calculation it is necessary to take into account the pitch of one screw of the equipment. It is calculated by the formula H=2pR* tga.

Description of symbols:

• 2n is a constant value of 6.28;
• R is the value of the radius that will describe the elements of rotation of the equipment;
• tg a is the section angle.

Calculation of an inverter for a wind generator

Before performing these calculations, the following point must be taken into account. If only one 12-volt battery is used in the home network, then there is no point in installing an inverter. The average power of a summer cottage or private household is about 4 kW, subject to maximum loads. For such a network, the number of batteries will be at least ten, each of them is designed for 24 volts. With so many batteries, it is advisable to use an inverter device.

But for these conditions, when ten 24-volt batteries are used, you will need a wind generator rated at 3 kW, at least. Weaker equipment will not be able to provide energy for such a number of batteries. For household appliances, this power may be too high.

The calculation of the power parameter of the inverter device is carried out as follows:

1. First, it is necessary to summarize the power characteristics of all energy consumers.
2. Then the time of consumption is determined.
3. The peak load parameter is calculated.

Alexander Kapustin showed the procedure for starting a wind generator with an inverter.

Efficiency

It is quite simple to evaluate the energy efficiency of a unit of a certain type and design, and compare it with the performance of similar engines.It is necessary to determine the coefficient of use of wind energy (KIEV). It is calculated as the ratio of the power received on the wind turbine shaft to the power of the wind flow acting on the surface of the wind wheel.

Wind energy utilization factor for various installations ranges from 5 to 40%. The assessment will be incomplete without taking into account the costs of designing and building the facility, the amount and cost of generated electricity. In alternative energy, the payback period for a wind turbine is an important factor, but it is also necessary to take into account the resulting environmental effect.

What is a wind generator?

A wind generator is a device that uses wind energy to generate electricity. Air currents, freely moving in the atmosphere, have gigantic energy, and, moreover, completely free. Wind energy is an attempt to extract it and turn it to good use.

A wind generator is a set of devices that receive, process and prepare energy for use. Wind currents interact with the rotor of the windmill, causing it to rotate. The rotor is overdriven (or directly) connected to a generator that charges the batteries. The charge through the inverter is processed into a standard form (220 V, 50 Hz) and supplied to consumption devices.

At first glance, the complex is rather complicated. There are also simpler designs, such as windmills that feed pumps. However, complex appliances require a complete set of equipment that can provide a stable and high-quality power supply.

Varieties of wind turbines

There are several types of wind generators.According to the number of blades, windmills are three-, two-, one-, multi-blade. Devices are produced without blades at all, where the “sail”, resembling a large plate, serves as the wind-catching part. Such equipment has a higher efficiency than other devices, but it is still not widely used. Interestingly, the fewer blades a windmill has, the more energy it produces.

Examples of flat wind turbines

According to the material used, the blades are rigid (made of metal or fiberglass) and cloth. The second type is the so-called sailing wind turbines, they are cheaper, but they lose to tough ones in practicality and efficiency.

Another important characteristic is the pitch feature of the propeller, which makes it possible to change the speed of rotation of the blades. Variable pitch devices allow you to maintain efficiency at different wind speeds. But at the same time, the cost of the system increases, and reliability decreases due to the complexity of the design. Therefore, in most cases, fixed-pitch devices are used, which are easy to maintain and reliable.

Types of wind turbines according to the location of the working axis

The working axis of rotation of the wind turbine can be located both vertically and horizontally

In both cases, there are advantages and disadvantages that you should pay attention to when choosing.

There are several types of vertical wind turbines:

1. Savonius wind generators, the design of which consists of several half-cylinders, which are fixed on an axis in a vertical position. The strength of such a device is the ability to work in any wind direction. But there is also a serious drawback - wind energy is used only by 25 - 30%.
2. In the Darrieus rotor, elastic bands are used as blades, fixed on beams without using a frame. The efficiency of the model is the same as that of the previous variety, but an additional installation is required to start the system.
3. Multi-bladed windmills are the most efficient among vertical devices.
4. The rarest option is devices with a helicoid rotor. Specially twisted blades ensure uniform rotation of the wind wheel, but the complexity of the design makes the price too high, which limits the use of mechanisms of this type.

Horizontal axis windmills are more common than vertical ones because they are more efficient but more expensive.

Types of wind turbines along the working axis

The disadvantages include the dependence of efficiency on the direction of the wind and the need to adjust the position of the structure using a weather vane. It is advisable to install a wind turbine of this type in an open area where it will not be covered by trees and buildings, and it is better away from the permanent place of residence of people. It is quite noisy and poses a danger to birds flying by.

Wind turbine manufacturers

The market includes both devices of foreign origin (mainly North America, Europe and China) and domestic installations. The price depends on the power and on the configuration - for example, the presence of solar batteries, and varies in the range from tens to hundreds of thousands of rubles.

Main technical characteristics

Models of controllers used as part of a particular wind turbine differ in their technical characteristics, reflected in the product passport, these are:

• Rated power, which is the main indicator of the device, must correspond to the power of the wind generator;
• The rated voltage, also the main indicator, must correspond to the voltage of the batteries that make up the wind turbine;
• Maximum power, determines the maximum allowable value for a specific device model;
• The maximum current characterizes the ability of the device to operate at the highest performance of the wind generator;
• The maximum and minimum voltage value on the battery determines the voltage range in which the device operates;
• If the model can work simultaneously with a wind turbine and a solar power plant - the maximum charge current generated by solar panels;
• Display type and operation parameters displayed on it;
• Operational characteristics - ambient temperature and humidity;
• Overall dimensions and weight.

Are all wind turbines the same?

many classifications for the manufacture of blades, to the earth's surface,

Most of the currently existing wind turbines (wind power plant) can be classified as one-, two-, three- or multi-blade. A small part of the most modern devices do not contain blades at all, and the wind in them catches the so-called "sail", which looks like a saucer. Behind it are the pistons that drive the hydraulic system, and already it generates electric current. The efficiency of such installations is higher than that of all others. In relation to bladed systems, the trend is as follows: the fewer blades, the more energy the generator produces.

Varieties of wind turbines

may be cheaper,

If we compare wind turbines according to the pitch of the propeller, then devices with a fixed pitch are more reliable. There are variable pitch windmills that can change the speed of rotation, but their bulky design entails additional costs for the installation and maintenance of such a system.

The designs of windmills are the most diverse, if we consider them from the point of view of the direction of the axis of rotation relative to the ground.

Devices whose blades rotate about a vertical axis, in turn, can be divided into several types.

1. Savonius wind generators are several halves of hollow cylinders inside, planted on a vertical axis. Their main advantage is the ability to rotate regardless of the speed and direction of the wind. A significant drawback is the ability to use wind energy by only a third.
2. A Darier rotor is a system of two or more blades that are flat plates. Such a device is easy to make, but it will not work to get a lot of energy with it. In addition, an additional mechanism is needed to start such a rotor.
3. The helicoid rotor, thanks to specially twisted blades, has a uniform rotation. The device is durable, but due to the complexity of the design, it is expensive.
4. Multi-bladed wind turbines with a vertical axis of rotation are the most efficient option in their group.

Windmills with a horizontal axis of rotation also have their advantages and disadvantages. Their main advantage is high efficiency.Among the disadvantages of such structures, it is worth noting the need to capture the direction of the wind with a weather vane and the change in efficiency depending on the direction of the wind. In this regard, horizontal installations are most appropriate in open areas. In the same place where the blades will be shielded from the wind by buildings, trees or, for example, hills, it is better to install a wind turbine of a different design.

In addition, such a wind turbine is expensive, and the appearance of it in the vicinity will definitely not cause great delight among your neighbors. Its blades can easily knock down a flying bird and make a lot of noise.

What other types of wind turbines are there? Well, of course, ours, domestic and imported. Among the latter, European, Chinese and North American units are in the lead. At the same time, the presence of domestic wind turbines on the market cannot but rejoice.

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The price of such devices is determined, first of all, by their power and the presence of additional elements, for example, solar panels, and varies over a very wide range - from several tens to several hundred thousand rubles.

Making a windmill with your own hands

The main work to be done is the manufacture and installation of a rotating rotor. First of all, you should choose the type of structure and its dimensions. Knowing the required power of the device and production capabilities will help determine this.

Most of the nodes (if not all of them) will have to be made independently, so the choice will be affected by what knowledge the creator of the structure has, what devices and devices he is best acquainted with. Usually, a trial windmill is first made, with the help of which the performance is checked and the parameters of the structure are specified, after which they begin to manufacture a working wind turbine.

Principle of operation

Further, the rotational force is converted into electricity, which is stored in the battery. The stronger the air flow, the faster the blades spin, producing more energy. Since the operation of the wind generator is based on the maximum use of an alternative energy source, one side of the blades has a rounded shape, the other is relatively flat. When the airflow passes over the rounded side, a vacuum area is created. This sucks the blade, pulling it to the side. This creates energy, which causes the blades to spin.

Scheme of operation of a wind generator: the principle of converting wind energy and the operation of internal mechanisms is shown

During their turns, the screws also rotate the axis connected to the generator rotor. When twelve magnets attached to the rotor rotate in the stator, an alternating electric current is created that has the same frequency as in ordinary room outlets. This is the basic principle of how a wind turbine works. Alternating current is easy to generate and transmit over long distances, but impossible to store.

Schematic diagram of a wind generator

To do this, it must be converted to direct current. This work is done by an electronic circuit inside the turbine.To get a large amount of electricity, industrial plants are manufactured. A wind park usually consists of several dozen installations. Thanks to the use of such a device at home, you can get a significant reduction in energy costs. The principle of operation of wind turbines allows them to be used in the following options:

• for autonomous work;
• in parallel with the backup battery;
• together with solar panels;
• in parallel with a diesel or petrol generator.

If the air flow moves at a speed of 45 km / h, the turbine generates 400 watts of electricity. This is enough to illuminate the suburban area. This power can be accumulated by collecting it in a battery.

A special device controls the charging of the battery. As the charge decreases, the rotation of the blades slows down. When the battery is completely discharged, the blades begin to rotate again. In this way, charging is maintained at a certain level. The stronger the airflow, the more electricity the turbine can produce.

How a wind turbine is powered from an alternative source

Windmills do not "feed" on the mass of air, they are tuned to consume wind speed. In other words: the wind approaches the wind turbine at a high speed and leaves it at a slower speed. The difference in wind speeds before and after the wind generator determines how much energy was absorbed by this device.

Some types of wind turbines do it better, some worse. But this is the main function of the wind generator - to slow down the wind.

The line between efficiency and limitation

Never believe the claims that a certain wind turbine operates at 100% efficiency.This means that the wind behind the blades of the windmill must completely stop. An absurd proof clearly demonstrates a false statement.

A wind turbine with ideal efficiency must find the balance where the wind gives off enough energy so that it only has to exit the aperture window of the device for further movement. The efficiency in this case determines the difference in wind speed before and after the turbine, directly affecting the power factor of the windmill, which takes the following formula: P_exit= 1/2 × r × S × V3 × efficiency.

The maximum efficiency of a wind turbine, more than 100 years ago, was substantiated by the German scientist Betz in his fundamental scientific work. Taking the above formula as a basis, the German extremely consistently substantiated that the maximum of 16/27 energy can be extracted from the wind. Subsequently, his calculations were slightly corrected by the Italian Loregio, and it turned out that the maximum efficiency for a wind generator is 59%.

This is clearly noticeable in the difference in the principles of operation of the Savonius and Darier turbines. After all, Savonius windmills take only the pushing force of the wind, and Darier's projects also use aerodynamic lift, which increases the speed of rotation of the blades.

The principle of operation of the wind turbine

In the absence or frequent power outages, it is better to make a mini wind generator or several wind turbines (wind turbines) for individual power supply with your own hands. A homemade device converts the kinetic energy of the wind into mechanical energy due to the rotation of the wind wheel.

Initially, the mechanical energy that rotates the rotor is converted into a three-phase alternating current.The energy flow through the controller is stored in a DC battery. Finally, the voltage inverter modifies the current to supply electricity to appliances and lighting.

The principle of operation of a windmill is simple and consists in the action of three types of force on the blades. Impulse and lifting overcome the braking force system and start the flywheel in motion. After the formation of a magnetic field by the rotor on the stationary part of the generator, the current starts through the wires.

Fields of application of the device

In fact, wind turbines are capable of providing energy to objects for various purposes. Wind turbines of large capacities are suitable for power supply on an industrial scale. Properly designed home-made devices give the owner of the site an uninterrupted power supply. You can make a wind generator for a private house with your own hands with minimal labor and money.

Advantages of the device

The main advantage of a home wind turbine is the savings on electricity bills. The money spent on parts and installation is repaid with free electricity supplies.

Additional advantages of a homemade wind turbine:

• the factory model is many times more expensive;
• environmentally friendly design that works without fuel;
• unlimited service life (in case of failure, components are easy to replace);
• suitability in suitable climatic conditions with an average annual speed of the meter from 4 m / s.

Flaws

The negative side of an individual windmill includes:

• dependence on the weather;
• storms and hurricanes often put the mechanism out of action;
• preventive measures are required;
• tall masts need grounding;
• some models exceed the permissible noise level.

Wind Turbine Generator

For the operation of windmills, conventional three-phase generators are required. The design of such devices is similar to the models used on cars, but has larger parameters.

Wind turbine devices have a three-phase stator winding (star connection), from which three wires exit, going to the controller, where the AC voltage is transformed into DC.

The generator rotor for a wind turbine is made on neodymium magnets: in such designs it is not advisable to use electrical excitation, since the coil consumes a lot of energy

To increase the speed, a multiplier is often used. Such a 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 turbines, in which the process of rotation of the wind wheel is slower. For horizontal devices with a high speed of rotation of the blades, multipliers are not required, which simplifies and reduces the cost of construction.

The specifics of the assembly and installation of a wind turbine from a washing machine and a wind turbine from a car generator are described in detail in the articles we recommend.

Set

• Bladed rotor. They, depending on the model, may be: one, two, three or more;
• Reducer or, in other words, a gearbox designed to regulate the speed between the generator and the rotor;
• The casing is protective. Its purpose is clear from the name: it protects all components of the structure from external influences;
• The tail is responsible for turning in the direction of the blowing wind;
• The battery is rechargeable.Its task is to accumulate energy, i.e. stock. Since the weather is not always favorable for the power plant, this will always help out in bad weather;
• inverter installation. It is used to convert direct current into alternating current, which feeds electrical appliances used in everyday life.

Calculation of size and placement

To calculate the required number of generators for a wind power plant, take into account:

• required power;
• number of windy days;
• location features.

So, in order for the installation of a wind turbine to be justified by the costs, it is necessary to determine the number of windy days per year, as well as their predominant direction. Seaside areas and areas in the mountains have the most advantageous location, since here the wind force exceeds 60-70 m / s, and this is quite enough to abandon local electricity.

On the flat territory, the wind is characterized by a uniform flow, but its strength is sometimes not enough to fully provide a private house. Installation near plantations and forests is unprofitable at all, since wind energy is consumed and lingers to a greater extent on trees.

The wind flow has an increase in power in direct proportion to the distance from the earth's surface. Accordingly, the higher the windmill mast, the more momentum it can capture. However, the further it is removed from the ground, the more reinforcement it requires. Auxiliary supports cannot always completely hold the windmill. In a strong gusty wind, the probability of a high mast falling is much greater than a mast set at a level of 5-7 meters.

The most optimal removal of the mast from the ground is 10-15 meters. Its fastening is carried out using two methods:

1. Foundation concreting - they dig four deep, but small pits in diameter, into which wind turbine extensions are immersed and concreted. The process is time-consuming and costly, but the most reliable. In a strong wind, the mast will remain motionless, and the only damage to it may be the scrapping of the blades.
2. Metal stretch marks - with the help of a metal cable, the windmill is fixed perpendicular to the surface of the earth, while the cable is well stretched, fixing its ends to the ground.

The duration of operation of the power plant as a whole depends on the choice of the method of fixing the mast.

The presence of special equipment, as well as experience in carrying out such work, will save the wind farm from premature breakdowns.

Sailing wind generator

If the blades of traditional windmills are made of hard materials, then in sailing, on the contrary, they are made of soft materials. Suitable for any dense fabric, such as tarpaulin. Often non-woven laminates are used in such constructions. Outwardly, a sailing wind generator looks like a large children's turntable.

By design, sailing windmills are divided into two types.

• Circular with triangular sail blades
• With a sail wheel, also circular

Sailing wind generator with triangular blades

Triangular sail blades are usually made isosceles, but in many cases their shape is selected individually - according to the wind loads of the area where they are installed. A sailing windmill starts working at a wind speed of 5 m / s. Its efficiency is higher than that of most bladed windmills, but at the same time it is not without many shortcomings. So when the wind changes, the “sailboat” stops and it needs time to spin in the new direction of the wind flow.

Another drawback is the fragility of the "sails" themselves. They often tear, fail and require a complete replacement.
It is believed that a circular sail generator is deprived of these shortcomings. Its efficiency is twice that of a generator with sail blades. Outwardly, it looks like a satellite dish and differs from the usual generators in that it does not have any rotating blades, cylinders or rotors. This generator vibrates under pressure or gusts of wind, transferring mechanical energy to the generator with its vibrations.