基于随机子空间法的风电塔筒模态参数识别研究

Identification of Wind Turbine Tower Modal Parameters Based on Stochastic Subspace Method

模态参数是结构的固有属性,是判断结构运行安全性的重要动态指标。针对风机结构的模态参数辨识问题,对四川A风场1.5 MW风电塔筒结构进行了数值模拟,得出了结构在风荷载下的振动响应。采用NExT联合SSI法的工作模态识别方法,利用稳定图对虚假模态进行剔除,同时利用NExT-ITD法进行对比。结果表明,辨识结果与理论值的对比验证了2种方法的可行性,2种方法都可以识别结构的模态参数,但NExT-SSI法相比于NExT-ITD法识别精度更高,更适合环境激励下风电塔筒结构的模态参数识别。

The modal parameters are inherent properties of the structure and are important dynamic indicators for judging the operational safety of the structure.To address the problem of modal parameter identification of wind turbine structures,numerical simulations of the 1.5 MW wind turbine tower structure at Sichuan A wind farm were conducted to derive the vibration response of the structure under wind load.The working modal identification method of natural excitation technique(NExT)combined with stochastic subspace identification(SSI)was used to reject the spurious modes using stability diagrams,and the NExT-ITD method was also used as a comparison.The results show that the comparison of the identification results with the theoretical values verifies the feasibility of both methods,and both methods can identify the modal parameters of the structure,but NExT-SSI is more accurate compared to NExT-ITD,which is more suitable for the identification of the modal parameters of the environmentally excited wind turbine tower structure.