A method to avoid negative damped low frequent tower vibrations for a floating, pitch controlled wind turbine
A method to avoid negative damped low frequent tower vibrations for a floating, pitch controlled wind turbine
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DOI：
10.1088/1742-6596/75/1/012073
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发表时间：
2007-07
影响因子：
7.3
通讯作者：
T. Larsen;T. Hanson
中科院分区：
文献类型：
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作者：
T. Larsen;T. Hanson
安装在浮动平台上的风力涡轮机受到与陆上风力涡轮机完全不同的软地基特性的影响。这导致与结构的刚体运动相关的低得多的固有频率，这再次导致塔架运动与涡轮机的桨距控制之间的不利耦合。塔架运动与空气动力学和桨距控制的组合将是不良的或甚至负阻尼的，如果不考虑的话，这将导致大的瞬态载荷。这种低阻尼的原因被证明是由与塔架的运动相比过快的俯仰调节引起的，或者换句话说，最低控制结构固有频率必须低于最低临界塔架频率。提出了一种控制算法，包括调谐方法（极点配置），以确保所需的控制频率，提供稳定的塔振动模式。
Wind turbines mounted on floating platforms is subjected to completely different and soft foundation properties, than seen for onshore wind turbines. This leads to much lower natural frequencies, related to the rigid body motion of the structure which again leads to an unfavorable coupling between tower motion and the pitch control of the turbine. The tower motion in combination with the aerodynamics and the pitch control will be poor or even negative damped which causes large transient loads if not accounted for. The reason for this low damping is shown to be caused by a too fast pitch regulation compared to the motion of the tower or in other words the lowest control-structure natural frequency must be lower than the lowest critical tower frequency. A control algorithm is presented including the tuning method (pole-placement) to ensure the desired control frequency which provides stable tower vibration modes.