模块化多电平换流器（MMC）的工作机制及其控制研究

发布时间：2018-02-12 02:24

本文关键词： 多电平换流器模块化多电平换流器(MMC) 载波层叠调制电压平衡稳定控制算法　出处：《河南理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着工业发展,能源矛盾日益突出,节能减排已成为我国重要任务之一。目前,多电平换流器的研究在高压大功率领域慢慢成为焦点,传统换流器拓扑结构,无论是二极管钳位结构、飞跨电容结构,还是H级联桥结构,大都不能很好实现四象限运行,这种换流器不能便捷地应用在像矿用提升机等需要快速启动制动、频繁正反转的调速系统,且制动能量无法直接回馈给电网,不能达到节能的效果;同时还存在网侧电流波形畸变严重、含有大量低次谐波、形成电力公害等问题。本文以模块化多电平换流器(Modular Multilevel Converter,MMC)为研究对象,讨论其逆变功能为主,研究其拓扑结构、数学模型、工作机制和控制算法,实现MMC换流器正常运行,并同过实验结果验证换流器在大功率方面的优异性。论文主要研究内容:(1)讨论了多电平换流器研究史以及研究MMC换流器的意义价值。通过分析MMC的拓扑结构及其工作机制,建立了基于开关函数的数学模型,在此基础上对调制技术做了深入研究,为实现系统正常运行奠定了理论基础;(2)针对MMC换流器子模块电容电压控制这一关键问题,提出基于排序建模法的电容电压平衡稳定控制策略。通过实时检测子模块电容电压并进行排序,根据每一相上、下桥臂电流方向,对子模块进行充电、放电或者旁路操作,达到控制电容电压平衡的目的;基于数学建模,设计闭环控制器,达到控制电容电压稳定的目的;(3)以Matlab-Simulink及RT-Lab半实物仿真设备为实验平台,仿真结果显示换流器运行正常、电容电压平衡稳定,输出电能质量高,谐波含量小,证明了本文提出的载波正负反相层叠调制技术与电压平衡稳定控制相结合的控制策略的可行性。同时设计了MMC换流器控制系统、主电路以及关键元器件选型。
[Abstract]:With the development of industry, energy contradiction is becoming more and more prominent, energy saving and emission reduction has become an important part of Ren Wuzhi. At present, the research of multilevel converter has gradually become the focus in the field of high voltage and high power. Whether it is diode clamping structure, flying capacitor structure, or H cascade bridge structure, it can't realize the four-quadrant operation well, and the converter can't be used conveniently in mining hoist and need quick start brake. The speed regulation system with frequent positive and inverse rotation, and the braking energy can not be directly fed back to the power grid, can not achieve the effect of energy saving, at the same time, there is serious distortion of the current waveform in the grid side, which contains a large number of low order harmonics. In this paper, the modular multilevel converter Modular Multilevel converter (MMC) is taken as the research object, its inverter function is discussed, and its topology, mathematical model, working mechanism and control algorithm are studied to realize the normal operation of the MMC converter. At the same time, the experimental results show that the converter is superior in high power. In this paper, the research history of multilevel converter and the significance of studying MMC converter are discussed. The topological structure and working mechanism of MMC are analyzed. The mathematical model based on switch function is established, and the modulation technology is deeply studied, which lays a theoretical foundation for realizing the normal operation of the system. (2) aiming at the key problem of capacitor voltage control of MMC converter submodule, The capacitive voltage balance and stability control strategy based on sequencing modeling method is proposed. The capacitor voltage of the sub-module is detected and sorted in real time. According to the current direction of each phase and the lower arm, the submodule is charged, discharged or bypassed. Based on mathematical modeling, the closed-loop controller is designed to achieve the purpose of controlling capacitor voltage stability. The simulation results show that the converter is running normally on the platform of Matlab-Simulink and RT-Lab hardware-in-the-loop simulation equipment. The capacitance voltage balance is stable, the output power quality is high, the harmonic content is small, The feasibility of combining the carrier positive and negative stack modulation technique with the voltage balance stability control is proved, and the MMC converter control system, main circuit and key components are designed.
【学位授予单位】：河南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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