The principle of wind turbine is that wind energy is converted into mechanical torque (the moment of inertia of the wind wheel) through the impeller, and the stator electric energy of the generator is increased to the speed of asynchronous generator through the spindle drive chain and gearbox, and then it is merged into the power grid by the excitation converter. If the synchronous speed of the generator is exceeded, the rotor will also be in the power generation state and feed the power grid through the converter. The simplest wind turbine can be composed of an impeller and a generator, standing on a tower shaft at a certain height, which is a small off-grid fan. The electric energy generated by the original wind generator changes with the wind, and the voltage and frequency are unstable, so it has no practical application value. In order to solve these problems, modern fans have added gear box, yaw system, hydraulic system, braking system and control system. The fan has many rotating parts, the engine room rotates on the horizontal plane, and the yaw is always aimed at the wind direction. The wind wheel rotates along the horizontal axis to generate dynamic torque. For variable pitch fans, the blades that make up the wind wheel should rotate around the central axis of the blade root to adapt to different wind conditions and change the pitch. When the machine stops, the blades should be feathered to form damping braking. The early hydraulic system was used to adjust the blade pitch (for shock absorption, parking, braking, etc.). ), now the electric pitch control system gradually replaces the hydraulic pitch control. As far as 1 0,500 kw fans are concerned, they usually start automatically when the wind speed is about 4m/s, and emit rated power at about 13m/s, and then with the increase of wind speed, they are always controlled to generate electricity near the rated power until the wind speed reaches 25m/s. The design limit wind speed of modern fans is 60-70m/s, that is to say, at such a high wind speed. Theoretically, the wind speed range of 12 hurricane is only 32.7-36.9 m/s, and the fan control system should operate at a stable voltage and frequency according to the wind speed and direction, and automatically connect and disconnect the power grid; At the same time, the working temperature of the gearbox and generator and the oil pressure of the hydraulic system will give an alarm to any abnormality and automatically stop when necessary, which belongs to an unattended independent power generation system unit.