三相模块化多电平换流器动态相量谐波分析模型

Harmonic Analysis Model of Three-Phase Modular Multilevel Converter Based on Dynamic Phasors

基于模块化多电平换流器(modular multilevel converter,MMC)的拓扑结构,将内部的桥臂电流和子模块电容电压作为研究对象,通过引入平均开关函数,推导出最近电平逼近调制下MMC的时域模型,再将其展开成动态相量谐波分析模型,从而求解得到稳态时MMC的交直流侧各次谐波分量。然后在Matlab/Simulink中搭建了MMC的仿真模型,并用快速傅里叶变化(fast fourier transformation,FFT)对其进行谐波分析,从而验证所建立谐波分析模型的正确性。最后根据模型分析了交直流侧谐波的相互作用。该模型可为设计MMC的滤波器或研究其谐波抑制技术提供理论参考。

Based on the topology structure of modular multilevel converter （MMC）, the internal bridge arm current and the sub-mod- ule capacitor voltage are taken as the object of study, by introducing the average switching function, the time domain model under nea- rest level approximation modulation of MMC is deduced, and then the model is expanded to a dynamic phasor harmonic analysis model so as to obtain the steady-state harmonic components of MMC at AC and DC side. Then, the simulation model of MMC is built in Matlab/Simulink, and the harmonic analysis is carried out by FFF to verify the correctness of the established harmonic analysis model. Finally, the interaction between AC and DC harmonics is analyzed according to the model. The model can provide a theoretical refer- ence for designing MMC filters or studying their harmonic suppression techniques.