在大型海上风电机组不断向风资源更加丰富的深海领域拓展的背景下，浮式风电机组以其在深海领域的成本下降潜力逐渐受到风电从业人员的关注。然而，浮式平台在海洋环境载荷作用下产生的六自由度运动不仅会对浮式风电机组的运行产生显著影响，也会加剧叶片载荷波动的复杂性。本文通过系统的风洞实验和数值仿真研究了风电机组在平台运动下的气动、尾流及载荷的非定常特性变化规律，提出新型风轮结构以降低大型海上风电机组叶片的载荷与质量，主要研究内容如下：首先，以风洞实验为基础，研究了指定频率和振幅的平台纵荡与横荡单一运动对风电机组模型的功率和推力特性的影响。结果表明，不同工况下的平台运动对风电机组平均功率和推力的影响都很小，但是平台纵荡运动会对风电机组的非定常气动特性产生显著影响。为此，提出了归一化推力变异系数以揭示不同工况下风电机组的非定常气动特性随平台运动参数的变化规律。然后，通过自主设计和搭建的三自由度实验平台，结合风洞实验和粒子图像测速系统，研究了指定频率和振幅的平台纵荡与横荡单一运动对风电机组近、中和远尾流的平均及瞬态速度分布的影响。结果表明，平台运动与固定工况之间的尾流平均速度差值波动主要出现在叶尖附近；提出了尾流侧向偏移距离以阐述平台横荡引起的瞬态尾流侧向偏移现象的变化规律。接着，利用OpenFAST软件评估了平台六自由度单一运动对NREL-5MW风电机组的功率和推力的影响。提取出对风电机组气动性能影响最大的纵荡和纵摇运动，利用ANSYS软件探讨了平台纵荡与纵摇运动对叶片载荷特性的影响，结果表明，平台纵荡运动会显著增加叶片载荷与应力的非定常性。最后，针对海上风电机组的大型化所引出的叶片轻量化问题，提出下风向-向前折叠式斜轴变桨的新型风轮概念。通过风洞实验研究了不同叶片折叠状态下新型风轮的功率特性，验证了其在功率调节方面的可行性。对新型风轮叶片进行轻量化设计，利用ANSYS软件对常规风轮和新型风轮的叶片应力特性进行对比，验证了其在实现叶片轻量化设计和降低叶片载荷方面的有效性。

With the development of large-scale offshore wind turbines towards deeper sea region with more abundant wind resources, floating offshore wind turbines (FOWTs) have attracted more attention from researchers of wind energy, due to their cost reduction potential in deep-sea region. However, the six degrees of freedom (6-DOF) motions of floating platform, induced by the ocean environment loads, not only have significant effect on the operation of the FOWTs, but also aggravate the complexity of blade load fluctuation. In this thesis, the aerodynamic, wake and load characteristics are investigated through systematic wind tunnel experiments and numerical simulation, and a novel wind turbine rotor concept is proposed to reduce the load and mass of large-scale offshore wind turbine blades. The main contents are summarized as follows:Firstly, the power and thrust characteristics of a wind turbine model subjected to surge and sway motions in prescribed amplitudes and frequencies are investigated through wind tunnel experiments. The results show that both motions have slight impact on the mean power and thrust of the wind turbine under various conditions, however, the surge motions have significant effect on the unsteady aerodynamic performance of the wind turbine. Herein, the normalized coefficient of variation of the rotor thrust is proposed to reveal the rules of variations for the unsteady aerodynamic performance with the motion parameters.Secondly, using a 3-DOF control apparatus which is original in design, the mean and instantaneous velocity profiles for the near, intermediate and far wakes of a wind turbine model subjected to surge and sway motions in prescribed amplitudes and frequencies are investigated, through wind tunnel experiments and particle image velocimetry. The results show that the fluctuations of mean velocity differences appear near the blade tips for both motions, with respect to the base-fixed cases. And the lateral offset distance between the velocity profiles is proposed to illustrate the variation rules of the phenomenon of instantaneous wake offset induced by the platform sway motions.Then, the influence of 6-DOF single platform motions on the power and thrust characteristics of the NREL-5MW wind turbine is studied numerically by OpenFAST software. The surge and pitch motions, which have the most significant influence on the aerodynamic performance of wind turbine, are selected as the platform motion conditions for the analysis of blade load characteristcis, using the ANSYS software. The results show that the surge motions lead to the increase of unsteadiness for the blade load and stress significantly.At last, aiming at the problem of blade lightweight caused by the upsizing of offshore wind turbines, a novel forward-folding rotor concept used in a downwind horizontal-axis turbine is proposed. The power characteristics of the novel wind turbine under various fold angles are investigated by wind tunnel experiments, and the feasibility of power output control using the novel rotor concept is verified based on the experimental results. Then, the blade lightweight design of the novel rotor concept is performed, and the blade stress characteristics of the novel rotor and the conventional rotor are compared with the ANSYS software. The numerical results validate the effectiveness of the the novel rotor in blade lightweight design and blade load reduction.