面向模块化多电平矩阵变换器双基频电气耦合特性的动态相量建模方法

Dynamic Phasor Modeling Method for Modular Multilevel Matrix Converter Considering the Double-fundamental-frequency Electrical Coupling Characteristics

模块化多电平矩阵变换器(modular multilevel matrix converter,M3C)具有复杂的拓扑结构和双基频电气耦合特性,当前对于其双基频谐波耦合机理及影响缺乏有效的建模研究方法。针对上述问题,首先,考虑到分频系统频率的独立调节特性,提出一种基于2维Fourier变换理论的双基频动态相量方法,可实现任意双基频谐波在2个基频维度上的分解。其次,基于该框架建立了M3C内、外环控制模型,进而建立了计及闭环控制系统的M3C 3阶谐波截断动态相量模型和小信号模型。最后,基于MATLAB/Simulink环境,通过频率及功率各异的3个运行点开展仿真验证。研究结果表明,所建模型具有较高的精度,误差主要来源于模型未能覆盖的更高次谐波;同时,根据所建模型的动、稳态特性分析结果,进一步验证了所提建模方法的正确性。

The modular multilevel matrix converter(M3C)has a complex topology and double-fundamental-frequency electrical coupling characteristics,and there is a lack of effective modeling methods to analyze the coupling mechanism of the double-fundamental-frequency harmonics.Firstly,considering the independence between the frequencies of the fractional frequency transmission system,we propose a novel double-fundamental-frequency dynamic phasor method based on the two-dimensional Fourier transformation theory.The method can achieve the decomposition of the doublefundamental-frequency harmonics on the two fundamental frequency spectra.Secondly,a double-loop control system is modeled based on the dynamic phasor frame,and then a dynamic phasor model with the 3rd-order harmonics truncated and a small-signal model are created after taking into account the closed-loop control system.Finally,based on the MATLAB/Simulink environment,simulation verification is conducted at three operating points with different frequency and power commands.The results show that the model has high accuracy,and the errors mainly come from the higher harmonics that the model fails to cover.Besides,the correctness of the proposed modeling method is further verified by the analysis results of dynamic and steady-state characteristics of the model.