Study On Vibration Characteristics And Stability Of Yaw Brake In Wind Power Under Variable Wind Load

The yaw brake can not only make the engine room of the wind turbine firmly fixed on the top of the tower,but also ensure the safety and stability of the yaw action when the engine room follows the change of wind direction.However,due to its low speed and heavy load working characteristics,frictional self-excited vibration occurs frequently.In addition,the entire engine room has a large inertia,which is prone to problems such as severe vibration and unstable yaw braking.Not only will the accuracy of the yaw movement be poor,but it will also cause an impact on the inside of the yaw brake,which will cause the yaw brake to malfunction,reduce its working life,and even bring safety hazards.This thesis analyzes the mechanism of the yaw brake vibration and combines the working characteristics of the yaw brake.The vibration characteristics of the yaw brake and the stability of the yaw brake under the change of braking parameters are studied respectively.The change law of the vibration characteristics of the yaw brake is obtained,and the working condition parameters that can reduce the vibration and improve the stability and accuracy of the yaw motion are obtained through the multi-objective optimization method.The main research content and research results are as follows:(1)Based on the multi-body dynamics method,taking into account the interaction between the upper and lower brake pads and the brake disc and the interaction between the brake pads,a three-degree-of-freedom yaw brake vibration mathematical model including brake discs and brake pads is established,and its force process is described mechanically.Based on this mathematical model,a rigid-flexible coupling simulation model of the yaw brake is established.The influence of different braking force and yaw speed on the axial vibration displacement and vibration intensity of yaw brake discs and brake pads is analyzed by the single variable method.The change law of the vibration characteristics of the yaw brake when the braking parameters change under the action of low speed and heavy load is revealed.(2)In actual working conditions,the operation of the yaw brake is affected by variable wind load.Perform equivalent processing of the variable wind load collected on the wind field to obtain variable wind load data,and input it into the rigid-flexible coupling simulation model of the yaw brake according to the space torque and force vector of the wind load coordinate system to simulate the effect of wind load on the yaw brake.By changing the braking force and the yaw speed,the effect of variable wind load on the vibration displacement and vibration intensity of the yaw brake is analyzed when the braking parameters change,and the influence law of variable wind load on the vibration characteristics of the yaw brake under different braking parameters is obtained.(3)Aiming at the performance requirement of yaw motion to improve the smoothness and accuracy of operation,based on the results of the influence of variable wind load on the vibration characteristics of the yaw brake.Above mentioned study has theoretical and practical significance for improving the stability and accuracy of yaw movement,but also provides a way to solve the yaw brake malfunctions.