Due to the instability and pulsation of the natural wind, the wind speed is high and sometimes small, and sometimes strong winds and storms occur. The speed of the wind turbine impeller changes with the change of the wind speed. If there is no speed regulation mechanism, The speed of the impeller of the wind turbine will be higher and higher as the wind speed increases. In this way, the centrifugal force generated on the blades will rapidly increase, resulting in damage to the impeller. In addition, as the wind speed increases, the speed of the impeller increases, and the output power of the wind turbine will inevitably increase. The overload capacity of the rotor coil and other electronic components of the wind turbine has a certain limit and cannot be increased arbitrarily. . Therefore, if the wind generator wants to have a stable power output, it must be equipped with a speed regulation mechanism.
In order to obtain energy from the wind, the rotating surface of the wind wheel should be perpendicular to the wind direction. In small wind turbines, this function is realized by the tail wing of the wind turbine as the direction adjustment mechanism. At the same time, as the wind speed increases, the speed of the wind wheel must be limited. This is because on the one hand, too fast speed will cause damage to the wind wheel and other parts of the wind turbine. On the other hand, it is also necessary to reduce the power of the generator. The output is limited to a certain range. Due to the relatively simple structure of small wind turbines, the impeller side-biased speed regulation method is generally used at present. This kind of speed regulation mechanism is likely to cause the wind wheel and tail to swing when the wind speed and wind direction change greatly, thereby causing the vibration of the wind turbine. . Therefore, when the wind speed is high, especially when the battery is fully charged, the wind turbine should be manually controlled to stop. In some small wind turbines, a manual brake mechanism is designed, and in practice, a sideways shutdown method can be used, that is, a soft rope is fixed on the tail. When it is necessary to stop, pull the tail to make the wind wheel sideways in the wind direction So as to achieve the purpose of parking.
The tail fin of the wind turbine is composed of a pin shaft, a tail rod and a tail plate, and the tail wing plays a role in adjusting the direction and speed of the wind wheel. The rear wing and the rear wing connecting lug on the revolving body are connected by a pin shaft, and the pin shaft has a designed space caster angle and side slip angle when installed. Due to the existence of this space caster angle and side slip angle, when the wind When the wheels are turning to adjust the speed, the tail will gradually tilt up, and the tilted tail will try to return to its original position under the action of its gravity. Once the wind speed is reduced, the recovery torque will force the tail to return to its original position under the action of the tail’s gravity. Make the wind wheel face the wind.
In many cases, no matter how the wind speed changes, the speed of the generator should be kept constant or not exceed a certain limit value. For this reason, a speed regulation or speed limit device is adopted. When the wind speed is too high, these devices are also used to limit the power output and reduce the force acting on the blades. There are various types of speed-regulating or speed-limiting devices, but in principle, there are roughly three types: one is to make the impeller deviate from the main wind direction; the other is to use aerodynamic resistance; the other is to change the pitch angle of the blade.
(1) Wind wheel side deviation speed regulation method. The principle of wind wheel side speed regulation is that when the wind speed is greater than the rated wind speed, the wind wheel is forced to sideways along the wind direction by twisting the wind wheel, so that the wind wheel deviates from the wind direction, reducing the wind-facing area of the wind wheel, thereby reducing the absorption of wind energy. When the wind speed reaches the cut-out wind speed, the rotating surface of the wind wheel is parallel to the wind direction, and the wind generator stops generating electricity.
(2) The blade variable pitch speed regulation method. The principle of blade pitch variable speed regulation is that when the wind speed is greater than the rated wind speed, a certain mechanism uses the centrifugal force of the wind turbine blade to change the pitch, reducing the wind energy utilization rate of the wind turbine, so as to achieve the effect of reducing wind energy absorption. When the wind speed is greater than the cut-out wind speed, the blades are parallel to the wind direction, and the wind generator stops generating electricity.
(3) Air brake speed regulation method. The air brake speed regulation method is to increase the blade resistance on the blades to achieve the purpose of speed regulation. The simplest device to increase the resistance is the air brake, such as installing flaps on the blades.