摘要随着社会和经济的不断发展，人类对电能的质量需求愈来愈高，以致煤炭、石油等一系列不可再生的化石能源大幅度消耗，人类生存的自然环境遭到了破坏，因为快速膨胀的开发和利用化石能源，引发了能源危机，阻碍生态文明的建设，不利于人类与自然的和谐相处。开发利用可再生能源已成燃眉之急，风能是一种新型绿色能源，因其具有发电利用率高的特点，适宜大规模开发与利用，而且占用土地面积少，已经成为我国能源开发的重点。80312

涉及到海上风力发电讨论的一个重要话题是传输系统，海上风力发电场可以使用交流或直流技术，这些技术之间的选择取决于传输系统连接到主电网的传输距离和功率容量。必须重视的是风力发电存在的间歇性问题，会对电网电能的质量产生影响。如果采用交流技术的方式，系统将会受到稳定性方面的制约，比如功角，频率稳定等，而且会产生其他许多问题。但是如果采用基于VSC-HVDC（利用电压源换流器技术的柔性直流输电）并网控制技术则不用考虑稳定性问题。

本文对基于VSC-HVDC系统的海上风电并网控制系统进行了介绍、分析、研究。高压柔性直流输电技术是一种新型直流输电技术，利用电压源换流器技术，以可控关断器件(如IGBT)以及PWM(脉宽调制)技术为基础。本文的主要内容包括以下几点:

（1）介绍海上风力发电发展的现状，并对海上风力发电机组进行比较；

（2）分析VSC-HVDC系统基本结构和工作原理，建立VSC-HVDC系统的数学模型；

（3）以建立的VSC-HVDC数学模型为基础，利用PID控制技术原理设计控制系统；

（4）建立VSC-HVDC的仿真模型，利用Matlab/Simulink进行仿真、调试, 对相关PID参数进行优化修改,分析仿真结果。

毕业论文关键词：VSC-HVDC，海上风电并网，PID控制,脉宽调制控制

ABSTRACT With the continuous development of society and the economy, the quality of human demand for energy rising, so that coal, oil and a series of non-renewable fossil energy consumption dramatically, the natural environment of human existence has been destroyed, because of the rapid expansion of development and the use of fossil fuels, causing energy crisis, hindering the construction of ecological civilization, is not conducive to harmony between mankind and nature。 Development and utilization of renewable energy sources has become urgent needs, wind energy is a green energy, because of its characteristics of high power generation efficiency, suitable for large-scale development and utilization, and take up less land area, it has become the focus of China's energy development。

Related to offshore wind power is an important topic of discussion is the transmission systems, offshore wind farms can use AC or DC technology, select depending on the transmission system between these technologies is connected to the transmission distance and the capacity of the main power grid。 Must pay attention to the presence of intermittent wind power issues will have an impact on the quality of grid power。 If the exchange of technical way, the system will be restricted stability, such as the power angle, frequency stability, and will have many other issues。 However, if a VSC-based HVDC (using the voltage source converter technology, flexible HVDC) grid control technology without considering the stability problem。

In this paper, based on HVDC offshore wind power grid control system is analyzed and studied。 By the voltage source converter technology HVDC flexible HVDC technology is a new technology, a controlled shut-off devices (eg IGBT) and PWM (Pulse Width Modulation) technology。 The main contents include the following:

（1）Describes the status of offshore wind power development, and offshore wind turbines are compared;