- 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?
A wind turbine converts kinetic energy in moving air into electricity. Large blades sit on a tall tower. Wind across those blades creates lift and the rotor turns, so a shaft drives an electrical generator. Cables in the tower collect the generated power.
Working of Wind Turbine
When wind strikes the rotor blades, lift starts the rotor turning. Many machines send that low-speed shaft through a gearbox so a smaller high-speed generator can run. Other machines couple the rotor directly to a large low-speed generator. Where a gearbox is used, its high-speed shaft drives the generator. A wound-field machine needs field current from an exciter or a converter. A permanent-magnet machine does not. Terminal voltage of a synchronous machine follows speed and field flux, but rotor speed is not left to the wind alone. Generator torque tracks an efficient tip-speed ratio below rated wind speed, and pitch holds speed and power at the rating above that. One full-converter layout takes the electrical generator(alternator) output through a rectifier to DC, then a line converter rebuilds grid-frequency AC for a step up transformer. A doubly-fed induction machine uses a different rotor-converter path. An internal supply unit feeds wind turbine auxiliaries (like motor, battery etc.).
A modern large turbine also uses two orientation controls.
- Blade pitch: turning each blade about its long axis.
- Yaw: turning the nacelle so the rotor faces the wind.
Gears plus small motors or hydraulics turn each blade at the hub. That pitch system may be electric or hydraulic. Below rated wind speed the blades stay near fine pitch while torque sets rotor speed. Above rated, pitch feathers the blades so power and rotor speed stay at the rating.
The nacelle, the housing on top of the tower, can rotate as the wind direction changes. An anemometer and wind vanes on the nacelle measure speed and direction. A controller then drives a yaw motor so the rotor faces the wind.
Internal block diagram of a wind turbine
