风能作为一种技术成熟、可靠性高的清洁能源，在全世界范围内得到广泛的关注与重视。近三十年以来，海上风电蓬勃发展，全球各国特别是欧洲国家已建成不少近海海上风力发电场，但开发成本较传统能源依旧十分昂贵。当前，大容量风力机的研发与应用以及采用漂浮式支撑基础的深水风电场是研究的热点与前沿，如何权衡风力机系统整体运行的安全与风电场开发成本是工程界和学术界共同关注的核心课题。为此，本文围绕海上风电场这一课题，针对实际工程前期设计和后期运营遇到的难点，在海上风电场短期风速预报、热带气旋极值风速估计、风浪联合作用下风力机系统整机动力响应以及漂浮式风力机系统初步概念设计这四个方面开展了相关工作。
本文对71年间（1945-2015）西北太平洋地区热带气旋数据进行整理，为探究热带气旋活动的变化趋势以及进一步给出相关海域的极值风速估计做好准备。同时，搜集了两组不同时间间隔的海上风电场实测风速数据，详实可靠的实测数据是开展风环境预报工作的必备条件。
在多尺度海洋风环境预报领域，分别开展了海上风电场短期风速预报和长期极值风速估计工作。基于时间序列分析方法，针对东海大桥风电场，通过分析实测风速数据，指出其短期风速序列的内在特性。在此基础上，定量对比了不同时间序列模型的预报精度，从而提出了适用于东海大桥风电场的短期风速预报模型。通过分析西北太平洋以及东海海域热带气旋活动的历史变化趋势以及空间分布规律，发现其在时间上呈现非平稳特性，在空间上呈现非均匀特性。进而采用非平稳极值风速预报理论，给出了东海海域及其子区域在不同重现期下的极值风速。
在漂浮式风力机系统动力响应领域，对一款开源计算程序进行二次开发，建立了漂浮式风力机系统全尺度动力学响应的计算力学模型。针对各类风浪联合作用下的海洋环境，特别是来流风向与波浪主方向存在夹角时的复杂海况，计算了典型立柱式风力机系统六个运动模态（纵荡、纵摇、横荡、横摇、垂荡、艏摇）的动力响应，揭示了在风波夹角变化的情况下，立柱式风力机的动力响应在时域内的变化规律和频域内响应功率谱的分布情况。
基于数值模拟方法，分别计算了采用两种典型浮式支撑基础（立柱式与半潜式）的风力机系统的整体动力响应，并对比分析了这两类浮式风力机系统各自动力响应的特点。在此基础上，结合两者结构特征，提出了一种新型漂浮式支撑基础的概念设计。研究了该系统纵摇、纵荡、升沉运动模态的动力响应随结构主要参数变化的规律，为进一步开发其他新型浮式支撑结构提供参考。

Wind energy, as a kind of clean energy with mature technology and high reliability, has received extensive attention around the world. Over the past 30 years, offshore wind energy industry has developed vigorously. Many offshore wind farms have been built in countries all over the world, especially in European countries, but the construction costs are still very high compared with traditional energy sources. At present, the research of large capacity wind turbines and offshore wind farms with floating support foundation are the research hotspots. How to balance the safety and reliability of the operation of wind turbines and the cost of construction is the core issue in engineering and academia. Therefore, this paper focuses on the subject of offshore wind farm, aiming at the difficulties encountered in the early design and later operation of practical projects, and carries out relevant work in four aspects: short-term wind speed prediction of offshore wind farm, estimation of tropical cyclone extreme wind speed, dynamic responses of wind turbine system with the combined action of wind and wave and preliminary conceptual design of floating wind turbine system.
In the dissertation, the data of tropical cyclones over the Northwest Pacific during the 71 years (1945-2015) are sorted out, in order to explore the trend of tropical cyclone activities and to further estimate the extreme wind speed in the relevant sea area. Meanwhile, two sets of measured wind speed data of offshore wind farms with different time intervals are collected. Detailed and reliable data are the necessary conditions for further wind environment prediction.
For multi-scale marine wind environment prediction, short-term wind speed prediction and long-term extreme wind speed estimation of offshore wind farms are carried out respectively. Based on the time series analysis method, the inherent characteristics of the short-term wind speed series of Donghai Bridge Offshore Wind Farm are pointed out by analyzing the measured wind speed data. On this basis, the prediction accuracy of several time series models are compared by quantitative analysis, and a short-term wind speed prediction model suitable for Donghai Bridge Offshore Wind Farm is proposed. Analyzing the historical tendency and spatial distribution of tropical cyclone activities in the Northwest Pacific and East China Sea, it is found that they are non-stationary in time and non-uniform in space. Based on the non-stationary extreme wind speed prediction theory, the extreme wind speed in the East China Sea and its sub-regions at different recurrence periods is given.
For dynamic responses of offshore floating wind turbine system, an open source calculation program is recompiled and a computational mechanics model of full scale dynamic responses of floating wind turbine system is established. In view of various typical sea conditions, especially the actual sea conditions where the angle between the wind direction of the incoming flow and the main direction of the wave exists, the dynamic responses of the motion modes of the typical vertical fan system are calculated, and then the variation laws and their respective characteristics are explored respectively in time and frequency domains.
The dynamic response of two kinds of classical floating structures (SPAR type and semi-submersible type) are calculated by numerical simulation, and the characteristics of their dynamic response are compared and analyzed. On this basis, combined with the structural characteristics of the two, a new type of composite floating support foundation is designed. Furthermore, the dynamic response of pitching, surge and heave motion modes varying with the main parameters of the structure is studied, which provides a reference for further conceptual design.