模块化多电平换流器的桥臂平均值模型

Bridge Average Value Model of Modular Multilevel Converter

模块化多电平换流器(MMC)的快速仿真模型是进行柔性直流输电系统相关研究的基础。在众多模型中,MMC的桥臂戴维南模型应用最为广泛,通过研究发现其仿真速度可以进一步提高。在MMC桥臂戴维南等效电路的基础上,利用能量均分思想提出了一种新的桥臂平均值模型。该模型显著减小了戴维南等效模型的计算负担,提高了模型的仿真效率。通过仿真验证了该模型可以适用于环流抑制、交直流侧故障仿真等应用场景。

The speed-up simulation model of modular multilevel converter (MMC) is the basis for the research of voltage-source converter high-voltage direct-current (VSC-HVDC) system. Among many models, the bridge Thevenin model of MMC is the most widely used. In this paper, it is found that the simulation speed can be further improved. Based on the Thevenin equivalent circuit of MMC’s bridge, a new bridge average value model (AVM) is proposed by using the idea of energy equalization. The proposed model significantly reduces the computational burden of Thevenin model and improves the simulation efficiency of the model. The simulation results show that the model can be applied to the application scenarios of circulating current suppression, AC/DC side fault simulation and so on, in which cases that do not pay attention to the capacitor voltage of sub-modules.