中文摘要：

模块化多电平矩阵式变换器（modular multilevel matrix converter,M3C）是一种可实现直接交交功率变换的新型拓扑,在未来高电压大功率异步混联系统中有着广阔的应用前景,因而对其数学模型及控制策略的研究具有十分重要的意义。论文通过对M3C换流系统的3个子换流器分别进行αβ0坐标变换,发现对称运行时桥臂中的非零序分量只与输入侧电气量有关,而桥臂中的零序分量只与输出侧电气量有关。基于此结论,论文首次提出了对M3C桥臂中电压、电流的非零序分量和零序分量分别进行输入频率、输出频率的dq旋转坐标变换,推导出了基于双dq坐标变换的M3C数学模型。该模型实现了系统输入输出两种交流频率分量的解耦,并将所有的交流电气量转换为直流量。在此基础上,论文提出了相应的矢量控制方案,该方案中所有的被控量在稳态时都是直流量,物理概念清晰,控制结构简单,比以往文献在αβ0坐标系下的控制方案更易实现控制的无静差特性。最后论文在Matlab平台上搭建了M3C换流系统模型并采用文中的控制方案进行仿真研究,仿真结果验证了所提数学模型的正确性和控制策略的优越性。

英文摘要：

Modular multilevel matrix converter （M3C） is a new topology of ac/ac power converter, which has very broad application prospects in asynchronous interconnection of high-voltage and high-power systems. Therefore, it＇s significant to study mathematical modeling and control strategy of M3C. By implementing αβ0 coordinate transformation in 3 subconverters respectively, it could be found that during symmetry operation the non-zero sequence component of each subconverter was only related to the components of input-side system and the zero sequence component was only related to the output-side components. Based on this conclusion, the paper first implemented dq coordinate transformation not only in the non-zero sequence components but also in the zero sequence components and thereby deduces the mathematical model of M3C under dq axis. The model decoupled two kinds of frequency components and converts them into DC components. The control strategy of the deduced M3C mathematical model was also proposed in this paper. Under this control strategy, all components were of clear physical concept and all controlled variables were dc components during steady state. Therefore, it was easier to ensure the non-error regulation of the control system compared to previous literatures which control M3C under αβ0 axis. The simulation results of M3C in Matlab environment verify the correctness of the mathematical model and superiority of the control strategy.