- Wind Turbine Definition: A wind turbine is defined as a device that converts wind energy into electrical energy using large blades connected to a generator.
- Working Principle of Wind Turbine: The turbine blades rotate when wind strikes them, and this rotation is converted into electrical energy through a connected generator.
- Gearbox Function: The gearbox increases the low-speed rotation of the turbine rotor to a high speed, which is necessary for the generator to produce electricity efficiently.
- Exciter and Controller: The exciter provides the needed magnetic field for electricity generation, while the controller adjusts the excitation based on wind speed to maintain stable output.
- Orientation Control: The turbine blades and nacelle are controlled to optimize wind capture, using pitch control for blade adjustment and a yaw motor for nacelle alignment.
How Does Wind Turbine Work?
Large blades are mounted on top of a tall tower. When wind hits these blades, they rotate because of their design and alignment. This rotation turns a shaft connected to an electrical generator, producing electricity that is collected through power cables.
Working of Wind Turbine
When the wind strikes the rotor blades, blades start rotating. The turbine rotor is connected to a high-speed gearbox. Gearbox transforms the rotor rotation from low speed to high speed. The high-speed shaft from the gearbox is coupled with the rotor of the generator and hence the electrical generator runs at a higher speed. An exciter is needed to give the required excitation to the magnetic coil of the generator field system so that it can generate the required electricity. The generated voltage at output terminals of the alternator is proportional to both the speed and field flux of the alternator. The speed is governed by wind power which is out of control. Hence to maintain uniformity of the output power from the alternator, excitation must be controlled according to the availability of natural wind power. The exciter current is controlled by a turbine controller which senses the wind speed. Then output voltage of electrical generator(alternator) is given to a rectifier where the alternator output gets rectified to DC. Then this rectified DC output is given to line converter unit to convert it into stabilized AC output which is ultimately fed to either electrical transmission network or transmission grid with the help of step up transformer. An extra units is used to give the power to internal auxiliaries of wind turbine (like motor, battery etc.), this is called Internal Supply Unit.
There are other two control mechanisms attached to a modern big wind turbine.
- Controlling the orientation of the turbine blade.
- Controlling the orientation of the turbine face.
The turbine blades are adjusted from their base hub using a system of gears and small motors or hydraulics. This system, called pitch control, can be electric or mechanical. It swivels the blades to align with wind speed, ensuring they capture the most wind energy efficiently.
The nacelle, or the turbine’s body, can rotate to face changing wind directions for maximum energy capture. An anemometer and wind vanes on the nacelle sense wind speed and direction. This data is sent to a control system that adjusts the nacelle’s position using a yaw motor, aligning the turbine with the wind.
An internal Block diagram of a wind turbine
