Accurate knowledge of wind turbine tower vibration damping is essential for the estimation of fatigue life. However, the responses in the fore-aft and side-side directions are coupled through the wind-rotor interaction under operational conditions. This causes energy transfers and complicates aerodynamic damping identification using conventional damping ratios. Employing a reduced two-degree of freedom wind turbine model developed in this paper, this coupling can be accurately expressed by an unconventional aerodynamic damping matrix. Simulated time series obtained from this model were successfully verified against the outputs from the wind turbine simulation tool FAST. Based on the reduced system obtained, a matrix-based identification method is proposed to identify the aerodynamic damping for numerically simulated wind turbine tower responses. Applying harmonic excitations to the tower allowed the frequency response functions of the wind turbine system to be obtained and the aerodynamic damping matrix to be extracted. Results from this identification were compared to traditional operational modal analysis methods including standard and modified stochastic subspace identification. The damping in the fore-aft direction was successfully identified by all methods, but results showed that the identified damping matrix performs better in capturing the aerodynamic damping and coupling for the side-side responses.

准确了解风机塔架减振对于评估疲劳寿命至关重要。然而，在操作条件下，前后方向和侧面方向的响应通过风轮相互作用而耦合。这导致能量传递，并且使使用常规阻尼比的空气动力学阻尼识别变得复杂。利用本文开发的简化的两自由度风力涡轮机模型，可以通过非常规的空气动力学阻尼矩阵准确地表示这种耦合。从该模型获得的模拟时间序列已针对风力涡轮机仿真工具FAST的输出进行了成功验证。基于获得的简化系统，提出了一种基于矩阵的识别方法，以识别数值模拟的风轮机塔架响应的空气动力学阻尼。在塔架上施加谐波激励可以获取风力涡轮机系统的频率响应函数，并提取出空气动力学阻尼矩阵。将该识别结果与传统的操作模式分析方法（包括标准和经过修改的随机子空间识别）进行比较。通过所有方法都成功地确定了前后方向的阻尼，但是结果表明，所识别的阻尼矩阵在捕获空气动力学阻尼和侧面响应耦合方面表现更好。将该识别结果与传统的操作模式分析方法（包括标准和经过修改的随机子空间识别）进行比较。通过所有方法都成功地确定了前后方向的阻尼，但是结果表明，所识别的阻尼矩阵在捕获空气动力学阻尼和侧面响应的耦合方面表现更好。将该识别结果与传统的操作模态分析方法（包括标准和改进的随机子空间识别）进行了比较。通过所有方法都成功地确定了前后方向的阻尼，但是结果表明，所识别的阻尼矩阵在捕获空气动力学阻尼和侧面响应的耦合方面表现更好。