节点文献
基于柔性直流中级联型模块化多电平换流器控制技术研究
Research on the Control Technology of Modular Multilevel Converter in the Field of VSC-HVDC
【作者】 项诚来；
【导师】 金新民；
【作者基本信息】 北京交通大学 ， 电气工程， 2012， 硕士
【摘要】 柔性直流输电技术是利用全控型电力电子器件输送电能的新型输电技术,柔性直流输电对于解决孤岛送电、新型能源接入电网、大电网互联、城市环网等领域具有重大意义,因此需要对柔性直流输电技术进行深入研究。本文主要研究了柔性直流输电技术和级联型多电平模块化结构换流器的基本工作原理、拓扑结构和控制策略。分析了级联型模块化多电平拓扑结构,并且阐述了其调制方式及其控制方法、通过仿真软件验证级联型拓扑结构应用在直流输电领域的可行性。级联型模块化多电平结构为柔性直流输电系统中一种MMC拓扑结构。该结构能够满足有功功率与无功功率解耦独立控制、黑启动、多端传输的功能。本文针对该结构控制方式的两个重要环节——脉冲调制方式的选择与系统级控制方法,进行了深入的研究和讨论。本文首先对目前柔性直流输电换流器结构进行对比分析,其中包括两电平与多电平及模块化拓扑结构与调制方式。其次,详细分析了级联型拓扑结构的工作原理、调制方式与电容参数的设计及电容电压平衡控制方法。然后对其换流站进行建模与仿真验证控制方式的正确性。本文阐述了目前各种柔性直流输电实际工程项目中的换流站拓扑结构,并比较了不同拓扑结构的优缺点以及使用特点等,重点分析了级联型模块化多电平换流器拓扑结构,并通过对级联型模块化多电平换流器模型的仿真,验证级联型换流器的可行性,它的输出电压电流波形更接近正弦波,在相同的开关器件条件下,大大降低了谐波污染。对级联型模块化多电平换流器进行了系统级与换流站级控制分析,详细论述在无源网络供电情况下的控制策略研究,并对其进行模型仿真。进一步验证级联型模块化多电平拓扑结构的可行性。
【Abstract】 VSC-HVDC(Voltage Source Converter-High Voltage Direct Current) transmission technology is the use of full-controlled power electronic devices conveying new electricity transmission and distribution technology。For solving the island power transmission, the field of new energy grid access, grid interconnection and urban ring network, VSC-HVDC is a great significance to study.In this paper, VSC-HVDC transmission technology and multi-level modular for the study of the basic working principle of the converter topology and control strategy to study the MMC topology, and described its control method and modulation mode, verify the feasibility of its application. This structure is VSC-HVDC transmission system half-bridge MMC on the basis of a new development, the structure can meet the decoupling of active and reactive power control, black start, multiport transfer function. In this paper, two important aspects of the structural control of the way-the choice of modulation mode and capacitor voltage balance control method, conducted in-depth study and discussion. First, comparative analysis of the existing VSC-HVDC structure, including a two-level and multi-level structure. Secondly, detailed analysis the working principle of the structure modulation with Capacitance voltage balance control strategies. Its system-level simulation, and control to meet the stability of the rectifier side and inverter side.This paper, the structure of specific technical theoretical elaboration and simulation studies, including VSC-HVDC transmission technology, PWM modulation technique, cascaded H-bridge multi-level modular inverter control strategy. MATLAB simulation of the above-mentioned technical result proved the correctness and feasibility of the system structure and control methods.