Wind Turbine Types and the principle of operation of wind turbines in the most basic form and the obtaining of electrical energy is based on the principle that the wind hitting the wings turns the rotor and the rotor drives the generator by means of shafts.
Basic energy conversion in wind turbine;
Machines that make rotations with the driven part and convert the energy in a fluid into mechanical energy in the shaft are called turbines.
Characteristics and Structure of Wind Turbines
The turbines used for wind power generation are modernization day by day thanks to technological advances and the subjects that are thought to be incomplete are complemented one by one. With performance enhancing systems, wind has improved step by step from windmills to modern turbines from yesterday to today. Now, in short, if we look at the overall structure of modern turbines;
- Modern wind turbines have 2-3 wings.
- The wing diameters are approximately 30 m.
- Wind speed variable over a period of time. However, the grid is given approximately immutable with energy, wind generator and wing properties.
- Energy production depends on the cube of the wind speed at rotor height and the sweeping area of the wings.
- Turbine power can vary from a few KW to several MW.
- Wind turbines can be installed on land as well as in the seas.
Wind energy conversion systems can provide mechanical or electrical power between 50W and 2-3 MW. Since the specific mass of the air is low, the energy to be provided from the wind depends on the wind speed. Wind speed increases in proportion to height and power increases in proportion to the cube of speed. The energy that the wind will provide depends on its strength and the number of blowing hours, the specific wind power is the power that falls on the surface of the unit perpendie to the air flow.
Basic parts of the wind turbine
- Propeller housing
- Propeller defragmenter
- Wing tilt bed
- Rotor Hub
- Central spindly bed
- Main shaft
- Brake disc
- Service crane
- Meteorological sensors
- Yaw gear
- Yaw bed
- Turbine base plate
- Oil filter
- Generator fan
- Oil cooler
Types of Wind Turbines – Classification of Wind Turbines
Wind turbines are divided into three parts: Horizontal, Vertical and Stony Axis according to wing structures:
Horizontal Axis Wind Turbines
The rotation axis is parallel to the wind direction and the wings are perpendie to the wind direction. Commercial turbines are usually horizontally axed. The rotor is placed on a rotating table to get the most out of the wind.
Most horizontally axated turbines are designed to take wind from the front. Turbines that take the wind from behind do not have a common use. In order for horizontally axial machines to hold maximum energy, their rotors must always be in the direction of wind flow. This is achieved by rotation of the rotor on top of the tower. Rotational motion in the direction of the wind is achieved by two different constructions. These are called "front-wind" and "back-wind".
If the wing takes the wind from the front, a guide wing is attached to the back of the rotor. In the other way, the wing takes the wind from the rear or the wings are made a little conical. Thus, the system follows the wind and provides maximum benefit.
Horizontal axis wind turbine
Vertical Axis Wind Turbines
The blades of this turbine, whose rotation axis is perpendie to the wind direction and vertical, are also vertical. Today, the majority of electrical power generation applications in various countries are 2 and 3-blade horizontal axis wind turbines. Large strong vertical axis applications are also available. In particular, Dorrieus type turbines and cyclogino-type wind turbines are used, which are more complex than those developed.
Vertical axis wind turbine
Stony Axis Turbines:
Rotation axis are wind turbines that make an angle in the direction of vertical and wind. There is a certain angle between the wings and rotation axis of such turbines.
Types of Generators Used in Wind Turbines
Any 3-phase generator can be selected in the Wind Turbine system.According to the generator used, even if the frequency of the current at the output of the generator is different from the mains frequency, it is possible to reach the standards to be integrated into the network thanks to the converters, even if the character of the current is direct current. In turbine systems:
a) Asenkron Generators
b) Synchronous Generators
It is the most commonly used generator type in wind turbine systems. The fact that it is robust and its mechanical structures are simple are features that make it attractive to use.The reactive current needs of the stator stim warn current is the main drawback.
Squirrel Caged Asenkron Generators
The squirrel caged asenkron machine can be connected directly to an AC system and operated at constant speed, as well as at variable speeds along with power electronics units. In order to reduce magnetic sounds and achieve good development momentum, the rotor grooves are opened in batter, not parallel to the mile, resulting in press aluminum casting rotor winding.
Squirrel caged asenkron machines are frequently used in practice because they have a brushless, reliable, economical and robust structure. Slippage, hence the rotor speed, varies with the amount of power generated. Changes in rotor speed are around 1-2%. Therefore, this type is advantageous when wind speed is constant.
Asenkron Generators with Bracelets
When using an asenkron generator with bracelet, the electrical characteristics of the rotor can be controlled externally. The windings of the winding rotor are connected by external sliding bracelets and brushes or by the power electronics device.
Using the power electronics device, the power can be transferred to the rotor circuit and magnetized with the generator, rotor or stator circuit. Thus, it is possible to restore the energy spent on the rotor circuit and give it to the output of the stator. The disadvantage is that it is more expensive than squirrel cage and is not robust compared to squirrel cage.