模块化多电平变换器建模仿真与实现.doc

摘要 本文分析了传统的多电平换流器的拓扑结构和优缺点，并在此基础上重点对模块化多电平换流器（Modular Multilevel Converter，MMC）的拓扑结构及其控制策略进行了深入研究。 首先介绍了多电平换流器的产生和发展过程，阐述了多电平换流器的应用，并对几种传统的多电平换流器的拓扑结构进行了对比分析，提出了一种新型的模块化多电平换流器拓扑结构。 本文详细分析了模块化多电平换流器的拓扑结构、子模块的拓扑结构及其工作机制，并以此为基础建立了模块化多电平的开关函数模型和瞬时功率模型，给出了桥臂电容电压波动和子模块电容电压和电流的时域解析表达式。 以数学模型为基础，提出了载波移相正弦脉冲宽度调制技术（CPS-SPWM）在模块化多电平换流器中的实现方法，研究了模块化多电平换流器桥臂子模块电容电压的预充电策略和电压均衡控制过程。 本文采用PSCAD/EMTDC对模块化多电平换流器进行建模和仿真，分析了模块化多电平的稳态响应特性和动态响应特性，验证了本文提出的控制策略有效性和可靠性，并对输出电压进行频谱分析，证明载波移相正弦脉冲宽度调制技术可以通过相互抵消低次谐波有效地实现较高的等效开关频率。在理论分析和软件仿真的基础上，本文采用FPGA实现了载波移相脉冲宽度调制技术，输出了脉冲波形，并与软件仿真波形进行了对比分析研究表明模块化多电平换流器具有模块化程度高，有效降低主控开关器件电压、电流容量等优点，采用载波移相正弦脉冲宽度调制技术的模块化多电平换流器的等效开关频率高，适合应用于高压大功率领域。 关键词：模块化多电平换流器，载波移相正弦脉冲宽度调制，FPGA Abstract With the continuous development of power electronics technology, high-voltage high-power full-controlled power electronic devices (IGBT, IGCT) have gainedrapid development, more and more in-depth research on high-power electronic converter device in large-capacity motor-driven and AC/DC power transmission and other occasions also become very popular. While in high-voltage high-power applications, there is a big contradiction between the power devices’ power handling capability and its toggle frequency. Under the premise that the power switching device has no essential breakthrough, the multi-level converter is undoubtedly the best choice to solve the high-voltage high-power applications. This paper analyzes the traditional multi-level converter topology and its advantages and disadvantages, and on this basis, focusing on the topology and control strategy of the modular multi-level converter (Modular Multilevel Converter, MMC) study. This paper firstly introduces the emergence and development of the multi-level converter, describes several applications of multi-level converter, conducts the comparative analysis on several traditional multi-level converters in topology, and then proposes a new modular multi-level converter topology. This paper made detailed analysis of the modular