采用加速度输入等效风力发电机组塔筒实测响应方法研究

Study on Response Equivalence Between Base Acceleration and Wind Loads in Wind Turbine Tests

通过对单自由体系的分析,得到风荷载激励和从基底输入的加速度之间的关系。通过对风力发电塔的模态分析,得到简化为广义单自由体系的广义质量和广义刚度,求得风力发电塔塔顶位移的时程曲线,采用Savitzky-Golay平滑算法和差分法求得顶点的加速度和速度时程,以此求得合成后的等效加速度。对直接合成后的等效加速度进行傅里叶变换,采用低通滤波器剔除高频分量,进行傅里叶逆变化后得到最终等效加速度。有限元分析结果表明,在此等效加速度下的结构响应和已知响应吻合一致,从而为风力发电塔的减振试验在振动台上完成成为可能。

The relationship between the wind load and the base acceleration is obtained by analyzing the dynamic response of single-degree-of-freedom system.Then the generalized flexural stiffness and the generalized mass of first vibration modal in wind turbine tower are achieved by the modal analysis.The top displacement history is derived from the base moment history,and so the velocity and acceleration history are obtained by Savitzky-Golay smoothing algorithm and the method of difference.The Fourier transform of the resulting acceleration from the difference is carried out and the low-pass filter is used to remove the high frequency components.The equivalent acceleration is achieved through the inverse Fourier Transform.In addition,the results of finite element analyses indicate that the dynamic response applied the base acceleration could agree well with that of the known response under the wind load.Therefore,the tests of vibration control for wind turbines could be carried out on the shaking table.