Parametric Instability and Localization of Vibrations in Three-Blade Wind Turbines
Parametric Instability and Localization of Vibrations in Three-Blade Wind Turbines
复制标题
DOI：
10.1115/1.4039899
复制
发表时间：
2018-04
影响因子：
2
通讯作者：
T. Ikeda;Y. Harata;Y. Ishida
中科院分区：
文献类型：
--
作者：
T. Ikeda;Y. Harata;Y. Ishida
对三叶片风力机的非线性振动特性进行了理论研究。该风力机被建模为一个耦合系统，由一个具有两个自由度的柔性塔和三个叶片组成，每个叶片具有单个自由度。叶片承受稳定的风。由于垂直风切变，风速随高度成比例增加。固有频率图是计算相对于风力发电机的转速。分析了相应的具有参数激励项的线性系统，以确定出现不稳定振动的转速，并预测在实际风力机中叶片在什么转速下可能产生高振幅振动。然后对非线性系统的运动方程进行扫频正弦检验，得到频率响应曲线。由于作用在叶片上的非线性恢复力矩，它们表现出软化行为。计算了平稳时程及其快速傅里叶变换（FFT）结果。在数值模拟中，观察到三片叶片以不同振幅振动的局部化现象。还计算了引力盆地（BOAs），以检验扰动对局域现象出现的影响。
Nonlinear vibration characteristics of three-blade wind turbines are theoretically investigated. The wind turbine is modeled as a coupled system, consisting of a flexible tower with two degrees-of-freedom (2DOF), and three blades, each with a single degree of freedom (SDOF). The blades are subjected to steady winds. The wind velocity increases proportionally with height due to vertical wind shear. The natural frequency diagram is calculated with respect to the rotational speed of the wind turbine. The corresponding linear system with parametric excitation terms is analyzed to determine the rotational speeds where unstable vibrations appear and to predict at what rotational speeds the blades may vibrate at high amplitudes in a real wind turbine. The frequency response curves are then obtained by applying the swept-sine test to the equations of motion for the nonlinear system. They exhibit softening behavior due to the nonlinear restoring moments acting on the blades. Stationary time histories and their fast Fourier transform (FFT) results are also calculated. In the numerical simulations, localization phenomena are observed, where the three blades vibrate at different amplitudes. Basins of attraction (BOAs) are also calculated to examine the influence of a disturbance on the appearance of localization phenomena.