配电网静止同步补偿器补偿电网不平衡的控制策略研究

发布时间：2018-06-24 18:23

本文选题：配电网静止同步补偿器 + 链式结构　；参考：《北京交通大学》2014年硕士论文

【摘要】：随着现代社会的发展,用户对电能质量要求越来越高,因此配电网中无功功率不足和不平衡等问题受到了广泛的关注。以提高用户侧电能质量为宗旨的用户电力技术(Custom Power或DFATCS)是一种将控制技术、电力电子技术和微处理技术等高新技术应用到配电系统中,以消除供电短时中断、电压波动和闪变及三相不平衡,补偿无功功率,减小谐波畸变,从而提高电能质量和供电可靠性的新型综合技术,是灵活交流输电系统(FACTS)向配电网的延伸。配电网静止同步补偿器(D-STATCOM)作为用户电力技术的代表装置,与其他设备相比具有性价比高、功能强大、性能优良等优点,能综合补偿配电网中的无功功率和不平衡等电能质量问题,具有非常广阔的应用前景。D-STATCOM不平静工况下的控制策略一直是研究的重点和难点,鉴于链式结构D-STATCOM较其他结构的优越性,本文以链式D-STATCOM为对象,对其补偿不平衡负荷的控制策略进行深入详尽的研究。首先,介绍了课题研究背景和意义,对D-STATCOM的国内外应用现状、主电路拓扑研究现状和控制策略研究现状作了简单介绍并比较了各种主电路拓扑和控制策略的优缺点。详细阐述了D-STATCOM的基本结构和基本工作原理,并利用正负序分离法和派克变换建立了不平衡工况下D-STATCOM的数学模型。其次,系统地阐述了微分几何法和滑模变结构控制理论,为后文控制策略的设计奠定理论基础。介绍了现有的补偿电网不平衡的控制策略并指出了存在的问题,为了克服传统控制策略补偿不平衡的缺点,提出了基于输入输出反馈线性化的正负序积分滑模变结构控制策略。其基本思想为将整个配电系统和D-STATCOM分成正序模块和负序模块,在利用输入输出反馈线性化方法将二者线化解耦成伪线性系统的基础上采用积分滑模变结构控制理论构成对各种干扰都有较强鲁棒性的控制策略。正序控制环节和负序控制环节分别补偿无功功率和负序电流,因此该控制策略适用于平衡及不平衡工况,能综合提高电能质量。最后,在PSCAD/EMTDC环境下搭建了仿真模型,在无干扰、只有内部干扰、只有外部干扰和内外部干扰同时存在的情况下进行仿真,验证所提控制策略的有效性和鲁棒性。
[Abstract]:With the development of modern society, the demand for power quality is getting higher and higher, so the problems of reactive power shortage and imbalance in distribution network have been paid more and more attention. Custom Power or DFATCS, which aims to improve the quality of power on the user side, is a kind of high and new technology, such as control technology, power electronics technology and micro-processing technology, which is applied to the distribution system to eliminate the short-time interruption of power supply. The new integrated technology of voltage fluctuation, flicker and three-phase unbalance, compensating reactive power, reducing harmonic distortion and improving power quality and reliability is the extension of facts to distribution network. Distribution network static synchronous compensator (D-STATCOM), as the representative device of user power technology, has the advantages of high performance-price ratio, powerful function, excellent performance and so on. In order to compensate reactive power and unbalanced power quality problems in distribution network synthetically, the control strategy of D-STATCOM has a very broad application prospect, which is always the focus and difficulty of the research. In view of the superiority of chain structure D-STATCOM compared with other structures, this paper takes the chain-type D-STATCOM as the object, and makes a thorough research on its control strategy to compensate the unbalanced load. Firstly, the background and significance of the research are introduced. The application of D-STATCOM at home and abroad, the research status of main circuit topology and control strategy are briefly introduced, and the advantages and disadvantages of various main circuit topologies and control strategies are compared. The basic structure and working principle of D-STATCOM are described in detail, and the mathematical model of D-STATCOM under unbalanced condition is established by using positive and negative sequence separation method and Pike transform. Secondly, the differential geometry method and sliding mode variable structure control theory are systematically expounded, which lays a theoretical foundation for the design of control strategy. This paper introduces the existing control strategies for compensating the imbalance of the power network and points out the existing problems. In order to overcome the shortcomings of the traditional control strategy to compensate the imbalance, a sliding mode variable structure control strategy based on the linearization of input and output feedback is proposed. Its basic idea is to divide the whole distribution system and D-STATCOM into positive sequence module and negative sequence module. Based on the linearization of input and output feedback, the two lines are coupled to pseudo-linear systems, and the integral sliding mode variable structure control theory is used to construct a control strategy which is robust to all kinds of disturbances. The positive sequence control link and the negative sequence control link compensate the reactive power and the negative sequence current respectively, so the control strategy is suitable for the balanced and unbalanced conditions, and can improve the power quality synthetically. Finally, the simulation model is built in PSCAD / EMTDC environment. The simulation results show that the proposed control strategy is effective and robust without interference, only internal interference, only external interference and internal and external interference.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM761

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