摘 要

世界经济的加快发展，使得全球能源资源的过分消耗，逐渐枯竭。而传统能源对环境也有重大危害，人们的眼光逐渐看向了清洁无污染又可再生的新能源领域。风能是一种可再生的清洁能源，而且风能总量非常大，且其发电技术已经十分成熟，故发展十分迅速。我国的西北和东北地区风能资源非常丰富，而电力市场主要分布在经济较为发达的地区，例如长三角、珠三角等沿海地带。这导致了我国风能利用存在困难，所以我国要想大规模利用风力发电，就必须在风能资源丰富区发电，然后进行远距离输电以更好地消纳风电。而柔性直流输电技术在远距离输电方面拥有众多优势，已成为风电传输的一种主流技术手段。

本文主要对风电孤岛接入柔性直流输电系统的控制策略进行了研究。首先分析了风力发电系统和柔性直流输电系统的工作原理，解释了DFIG实现变速恒频的机制，说明了VSC-HVDC系统可以对有功功率和无功功率进行控制。然后分别提出了DFIG和VSC-HVDC系统的控制策略，介绍了DFIG风力机最常用的控制——采用PI控制器，将三相交流量通过坐标转换变为两相直流量，然后再对直流量进行控制；还介绍了VSC-HVDC系统经典的双环控制策略，并举出了具体的实例控制进行分析，提出了适用于孤岛运行模式下的定频率控制策略。接着对风力机组和柔性直流输电系统进行了数学建模。最后在MATLAB/Simulink环境下搭建了风电孤岛接入柔性直流输电系统的仿真模型，分别选择接入1台、2台和10台风机进行模拟仿真，验证了所提出控制策略的有效性。

关键词：风电；孤岛；柔性直流输电；控制策略

Abstract

The accelerated development of the world economy has gradually exhausted the excessive consumption of global energy resources. However, traditional energy sources also do great harm to the environment. People's eyes are gradually turning to clean, pollution-free and renewable new energy fields. Wind energy is a kind of renewable clean energy, and the total amount of wind energy is very large, and its power generation technology is very mature, so the development is very rapid. China's northwest and northeast regions are rich in wind energy resources, while the electricity market is mainly distributed in economically developed regions, such as the Yangtze River Delta, Pearl River Delta and other coastal areas. This leads to difficulties in the utilization of wind energy in China. Therefore, if China wants to use wind power on a large scale, it must generate electricity in areas rich in wind energy resources, and then conduct long-distance transmission to better absorb wind power. Flexible direct current transmission technology has many advantages in long-distance transmission and has become a mainstream technology for wind power transmission.

This paper mainly studies the control strategy of wind power isolated island connected to flexible direct current transmission system. Firstly, the working principles of wind power generation system and flexible direct current transmission system are analyzed, the mechanism of DFIG to realize variable speed and constant frequency is explained, and VSC-HVDC system can control active power and reactive power. Then, the control strategies of DFIG and VSC-HVDC systems are proposed respectively, and the most commonly used control of DFIG wind turbine is introduced, which uses PI controller to convert three-phase AC quantity into two-phase direct flow through coordinate conversion, and then controls the direct flow. The classical double loop control strategy of VSC-HVDC system is also introduced, and the specific example control is analyzed, and the fixed frequency control strategy suitable for isolated island operation mode is proposed. Then the wind turbine and flexible DC transmission system are modeled mathematically. Finally, a simulation model of wind power isolated island connected to flexible direct current transmission system is built in MATLAB/Simulink environment. One, two and ten wind turbines are respectively selected for simulation, which verifies the effectiveness of the proposed control strategy.

Key words: wind power; island; VSC-HVDC; control strategy

目录

第1章 绪论 1

1.1研究背景及意义 1

1.2国内外研究现状 1

1.2.1风电发展现状 1

1.2.2风电孤岛接入柔性直流输电系统的研究现状 3

1.3本文的主要研究内容 5

第2章 风电孤岛接入柔性直流输电系统的工作原理及控制策略 6

2.1风电孤岛接入柔性直流输电系统的工作原理 6

2.1.1风电机组的工作原理 6

2.1.2柔性直流输电的工作原理 7

2.2风电孤岛接入柔性直流输电系统的控制策略 9

2.2.1DFIG矢量控制策略 9

2.2.2VSC-HVDC联网控制策略 12

2.2.3VSC-HVDC孤岛控制策略 13

第3章 风力机和柔性直流输电系统的数学建模 16

3.1风力发电机的数学模型 16

3.2柔性直流输电系统的数学模型 18

第4章 系统仿真验证与分析 21

4.1系统仿真模型及参数 21

4.2系统仿真结果分析 22

第5章 总结与展望 30

5.1全文总结 30

5.2课题展望 30

参考文献 32

附录A 34

附录B 35

致谢 36

第1章 绪论

1.1研究背景及意义

近年来，中国经济发展迅速，这就导致了能源消耗量越来越多，能源逐渐枯竭。能源供给与经济发展是一个很矛盾的关系，能源危机也会使中国的经济发展受到限制。如今，常规能源逐渐减少，再加上传统能源对生态环境的影响非常大，人们的目光都转向的可再生能源，世界各地都在新能源方面投资巨大。其中风能是发展最全面、最具规模化发展前景的可再生能源。

相比较于传统能源，风能具有多方面的优点，它对环境没有污染，并且是一种可再生能源，他还可以对大电网的结构进行补充，还可以作为偏远地区的能源来源。所以近年来风力发电得到了大力发展。