基于行程约束TMD/HMD的海上浮动风力机结构振动控制理论及实验研究

The offshore floating wind turbine generator system is a complex fluid-solid multi-body coupled system, in which the floating support platform adds 6-DOFs rigid motion and combined effects of wind and wave loads, and its dynamic couplings may lead to excessive vibrations and extreme fatigue loads in the blades, support structure, and even structural instability. The TMD (tuned mass damper) or HMD (hybrid mass damper) structural controlling technique is applied to vibration control of floating wind turbine structures, which has become one of the research hotspots in the fields of international floating wind turbine dynamics recently..Through our previous researches, due to the limited space in the nacelle or the platform of the floating wind turbine, the vibration control of floating wind turbine based on TMD or HMD is conditioned by the constraint problem of the stroke length of the TMD or HMD’s auxiliary mass which is a bottle-neck problem. In order to solve this problem, the main research topic for this project is to develop the structural vibration control theory and experimental techniques of the floating wind turbine based on TMD and HMD with their auxiliary masses stroke limited. First, the simplified coupled aero-hydro-structural-TMD/HMD controlled dynamics model of the Spar type floating wind turbine will be established based on Lagrange equation. Second, the nonlinear damper and stiffness position-limited control strategies will be proposed to limit the maximum stroke of the auxiliary mass and the mechanism about the position-limited control strategies will be also studied. Finally, new structural control methods will be investigated for floating wind turbine based on TMD and HMD under the position-limited control strategies, which will be reduce vibration responses and fatigue loads of the floating wind turbine. Research results will be extremely important for floating wind turbines, allowing for increased reliability and possibly lighter and cheaper structures.

海上浮动基风力机由于其浮动平台的刚体运动与风机结构振动的强耦合特性而导致的过大振动及极端载荷直接威胁风机结构的稳定性与安全性，利用TMD等结构控制技术抑制浮动风力机的过大耦合振动是近年来国际风机动力学领域的研究热点。申请人前期研究发现，由于机舱及浮动平台内空间有限，TMD/HMD控制器的辅助质量的行程受限问题是制约浮动基风力机结构主被动控制研究的瓶颈。本课题拟研究建立海上浮动风力机的气动-水动-结构-TMD/HMD控制相耦合的受控动力学简化模型，提出表征TMD/HMD行程约束特点的非线性限位策略及实现方法，揭示其对TMD/HMD控制及受控风机动力学特性的影响机理，并探索基于非线性限位约束TMD/HMD的浮动风力机结构主被动控制的新理论及新方法，发展海上浮动基风力机结构动力学控制基础理论及创新实验技术，为我国未来海上浮动基风力机的研制开发提供理论基础及技术储备。

在远深海强风大浪作用下，海上浮动风力机的浮式平台、塔架、叶片等构件将产生巨大的振动响应，严重影响结构的安全性与可靠性。因此，对海上浮动风力机进行振动主被动控制研究是当前的国际热点课题。本基金项目以Spar式浮动风力机为研究对象，从浮动风力机结构的振动规律、主被动控制方法及实验验证等方面进行了研究，完成主要研究内容及成果如下：（1）建立了14自由度（DOF）Spar式风力机的气动-水动-伺服控制-结构耦合的多体动力学模型，揭示了风力机浮式平台pitch运动和塔顶fore-aft挠度的耦合运动规律。发现由于叶片桨距角的影响，高风速作用下的平台pitch和塔顶fore-aft挠度与低风速的结果相差不大。（2）在浮式平台和机舱中安装具有调谐质量阻尼器（TMD）行程约束的新型被动控制装置抑制Spar式风力机的振动响应，研究了TMD系统的减振机制。仿真结果表明，平台TMD能有效降低pitch运动，机舱TMD可以减少塔顶fore-aft挠度；不同载荷工况下，TMD系统对平台pitch运动标准差的最大减振率可达39%，对塔顶fore-aft标准差的减振率约为53%。（3）开发了Spar式风力机气动-水动-伺服控制-结构-TMD-HMD主动控制程序，弥补了FAST程序只有TMD被动控制系统的不足。基于改进LQR算法、变增益H算法及自适应模糊控制理论设计了多种主动控制器，研究了各类控制器对浮动风力机振动的抑制效果。结果表明，不同工况下，H控制器对塔顶fore-aft的功率谱密度（PSD）峰值的减振率可达95%以上。（4）开创性地开展了TMD被动控制实验研究，研制了1:100的Spar式风力机缩尺模型及机舱TMD减振系统，验证了机舱TMD抑制塔顶fore-aft振动的原理。实验表明，机舱TMD系统对塔顶fore-aft振动的PSD峰值减振率可达80%。本项目研究加深了对海上浮动风力机复杂振动特性的了解，初步形成了TMD/HMD对海上浮动风力机振动控制的自主研发能力，推动了海上浮动风力机振动控制从理论研究到实际应用的转化，为我国海上浮动风力机振动控制技术提供了理论基础和技术储备。