Research On Vibration Control Technology Of Flexible Tower Of Offshore Wind Turbine

As an important part of connecting wind turbines,cabins and basic components,the tower can support wind turbines to obtain wind and power generation.With the vigorous development of large-scale offshore wind turbines,the development trend of ultra-high-speed flexible tower is unstoppable.From the design cost of wind turbine,the tower accounts for about 15% to 20%.To reduce design costs,towers are mostly made of lightweight materials.Under the influence of tower height and material,the flexibility of the tower is gradually increased,and its low damping aggravates the vibration effect of the tower.In order to maintain the steady power generation of wind turbines and reduce fatigue loads on critical components,this paper uses a combination of mechanical and electrical controls to control tower vibration,the main work is as follows:1)In view of the vibration problem brought about by ultra-high flexible tower,the difference between rigid tower and flexible tower is expounded according to frequency factor,and the structural characteristics of flexible tower are studied.In GH Bladed,the tower pattern analysis of 8MW offshore wind turbine is carried out,and the main source and frequency resonance area caused by tower vibration are analyzed by Campbell diagram,which provides the basis for the design of tower vibration control strategy.The dynamic structure response of the tower under the influence of different temperature and height under the external environment of wind turbine and wind and wave load was studied.2)In view of the low frequency problem of flexible tower,the TMD-based tower vibration control system is designed from a mechanical angle,which is installed in the cabin.The structural model of the TMD control system is given.The TMD control system solves the problem of vibration ability caused by the low frequency of flexible tower to some extent.3)Under the influence of wind and wave load,the force analysis is carried out on the tower,and in order to effectively control the vibration of the tower,the tower vibration control system based on independent paddle pitch is designed in the field of electrical control.The variable pitch control system optimizes the pitch angle output according to the generator speed deviation and the blade root load.At the same time,the vibration speed of the tower is used as the feedback signal to further adjust the pitch angle output.The filter is used to suppress the blade vibration and further increase the vibration control effect of the tower.The TMD control system and the independent paddle pitch ingress system for tower vibration are simulated and verified in GH Bladed,and the results show that the vibration control effect of the tower is effectively realized by the combination of two control strategies.