| Wind power generation is one of the most important forms of wind energy utilization.In order to fully exploit the wind energy resources in each wind field as far as possible,wind turbines begin to develop towards large-scale,and more and more large blades are applied to practice.With the increase of the size,the stiffness of the large blade decreases rapidly along the span direction,and the damping difference between the inside and outside of the surface increases,which is prone to irregular vibration,resulting in frequent accidents such as blade breakage and tower collapse of large wind turbines.Therefore,in view of the vibration damage of large blades,two types of vibration control devices are proposed based on the basic principles of TMD.The influence of the parameter values of the two vibration control devices on the vibration control performance are discussed in detail.The response variation laws of the blade with two devices are compared and analyzed,and the applicable vibration control conditions and pros and cons of each device are obtained,which provides a corresponding reference for the later blade vibration control.The research contents of this article mainly include the following points:(1)The exponential model and the logarithmic model are used to explore the difference in average wind speed between the blades in uniform rotating state and parked state and the influence of the two models on the calculation is analyzed.The Karman source spectrum and the rotation sample spectrum are used to analyze the difference in the pulsating wind speed of the blade in the two states.The results show that when the blade is in a rotating state,its average wind speed changes periodically with time.Compared with the Von-Karman source spectrum,the rotation sample spectrum has a significant difference in the energy distribution in the high-frequency part and there is an oscillation phenomenon.These are quite differences between the blades in uniform rotating state and park state.Only from the perspective of frequency analysis,considering that the vibration frequency of the blade in uniform rotating state is greater than that in the parked state,controlling the dynamic response of the blade in rotating state can more effectively reduce the frequency of wind power accidents.(2)Ignoring the influence of factors such as the nacelle and tower of the wind turbine,the single blade is simplified as Bernoulli Euler beam rotating with the hub,and it is only considered as a generalized single degree of freedom system with a single bending deformation along the edgewise direction.The dynamic equation of the wind turbine blade considering the rotation effect are derived combined with Euler-Lagrange theory,and the dynamic model of the wind turbine blade without vibration control device is established.(3)Based on the special structure of wind turbine blade and the principle of TMD,two types of vibration control devices with different structures are proposed,and the coupling dynamic equations between the damping device and the blades are derived.The calculation models of the wind turbine blade with devices are established in Matlab/Simulink.(4)Using the control variable method,the various parameters of the vibration control devices are combined into different working conditions,and the influence of parameter variation are discussed under each condition on the response of the blade.Considering whether the internal space of the blade meets the operation requirements of the devices,the optimal parameter configurations of the vibration control devices are obtained,and the control effects of different devices on the response of the blade are compared and analyzed.The results show that the two proposed vibration control devices have good control effects on the various responses of the blade,but considering the limited space inside the blade,the unidirectional cable pendulum device has a higher cost performance. |
