【作者】 梁海峰；

【导师】 李庚银；

【作者基本信息】 华北电力大学（河北） ， 电力系统及其自动化， 2009， 博士

【摘要】 柔性直流输电(VSC-HVDC)技术极大地拓展了直流输电的应用范围。由于其在控制灵活性、环境保护、电力交易、绿色能源并网和提高电能质量等方面的优良特性,成为当前输配电领域的研究热点之一。尤其在我国尚无实际工程的情况下,许多应用基础问题仍需深入研究。本文特别关注了VSC-HVDC的数学模型、控制策略和实验系统等问题。从VSC-HVDC系统的模型、控制体系、控制策略及实验系统的研制等方面进行了研究,取得的主要成果如下:(1)推导了abc以及dq0坐标系下VSC-HVDC系统的数学模型。基于VSC-HVDC系统的低频数学模型,建立了VSC-HVDC系统的动态等效电路。通过该电路可以清晰方便地分析VSC-HVDC系统中各变量扰动时的动态特性。对VSC-HVDC系统静态特性的研究进一步揭示了VSC-HVDC的运行机理。(2)构建了VSC-HVDC系统控制体系框架,具体提出了建立四层结构的VSC-HVDC系统控制体系框架的观点,即直流系统控制层、换流器控制层、阀组控制层和独立控制层四层结构。阐述了VSC-HVDC控制系统的基本功能,指出了采用多重化配置和分层控制结构设计的必要性,明晰了控制系统各层次的控制功能和控制范围以及各控制层次之间的关系,为VSC-HVDC控制系统的开发奠定了基础。(3)设计了VSC-HVDC系统H_∞控制器。针对PI控制器设计的缺点和从提高系统鲁棒性的角度出发,采用H_∞控制理论分别设计了VSC-HVDC面向无源网络和两端联接有源网络的H_∞控制器。为了更好地抑制交流系统电压扰动对VSC-HVDC系统的影响,在对数学模型进一步推导的基础上,设计了考虑系统电压扰动的VSC-HVDC H_∞控制器。(4)设计并完成了VSC-HVDC实验系统,包括主电路、控制子系统和监控子系统三部分。利用所建立的实验系统,进行了向无源网络和两端联接有源网络供电的实验。为了弥补常规PI控制器的缺陷,设计了模糊自适应PI控制器,该控制器能够实现自动调整PI参数,较好地适应了系统的各种变化,实验结果验证了它的有效性。(5)提出了多端VSC-HVDC系统的三种基本结线方式,包括并联结线方式、串联结线方式和混合结线方式。其中,混合结线方式又可以分为串并联结线方式和并串联结线方式两类。给出了三类结线方式的结构图,详细分析了它们各自的特点,并验证了这些结线方式的可行性。更多还原

【Abstract】 VSC-HVDC greatly extends the range of application of HVDC. It has been a highlight of transmission and distribution field for the excellent characteristics of control flexibility, environmental protection, power exchange, green energy supply and improving power quality. There are still many application questions needing to be further studied, especially for no practical VSC-HVDC project operating in our country.This dissertation focuses on the attention to mathematical model, control strategy and experiment system of VSC-HVDC and deeply studies the founding of mathematical model and control system framework, the design of controller and the development of experiment system. It includes the following contents.1. The mathematical models in abc and dq0 coordinate are derived. Based on omitting high-frequency component of switching function, a dynamic equivalent circuit of VSC-HVDC is founded. By use of the dynamic equivalent circuit, the dynamic performances of VSC-HVDC system are easily gained. The analysises to the VSC-HVDC system static performances further reveal the operation mechanism of VSC-HVDC.2. The control system framework of VSC-HVDC is founded. A four-layer structure of the control system framework of VSC-HVDC is proposed concretely, which is made up with the DC system control layer, converters control layer, separate control layer and valves control layer. The paper clarifies the basic control functions of the control system of VSC-HVDC and points out that the redundancy configuration and the multi-layer structural design are necessary. Based on the principles of configuration of each layer, the paper describes the control functions and scope of each control layer at details. In view of the close correlation between the control system and the protection of VSC-HVDC system, the paper further discusses the coordination issues between them.3. VSC-HVDC H_∞controllers are designed. Focus on the shortcoming of PI controllers design and from point of view of improving the control system robustness, the H_∞controllers of supplying to passive network and active network are design according to H_∞theory. For the sake of restraining the influence from disturbances of AC system voltage, the H_∞controller considering disturbances of AC voltage is designed. 4. VSC-HVDC experiment system is designed and implemented. It includes main circuit, control subsystem and monitor subsystem. By use of the experiment system, the tests of supplying to passive network and active network are gone on. A fuzzy adaptive PI controller that can automatic regulate PI parameters is implemented. The experimental results show that the fuzzy adaptive PI controller is effective.5. Three basic connection types of multi-terminal VSC-HVDC system, including Parallel, Series and Hybrid connection, are proposed. Hybrid connection can be divide two kinds of connection types again. One is series-parallel type and the other is parallel-series type. The structure diagrams and characteristics of the three types are analyzed. Simulation results show that the proposed connection types are feasible.更多还原