适用于全桥MMC等效模型的线性排序均压算法

模块化多电平换流器(modular multilevel converter,MMC)已在直流电网和新能源汇集等领域发挥重要作用。随着直流电网的发展,全桥MMC在直流故障穿越中起到了非常重要的作用,而已有的MMC等效模型在仿真超高电平MMC多端直流电网时,受排序算法复杂度的影响,仿真效率依然较低。有文献基于开关器件关断电阻无穷大并采用后退欧拉法,针对一种理想型的全桥型MMC等效模型提出了一种线性排序算法。本文以快速嵌套同时求解法为基础,证明了在梯形积分和后退欧拉电容离散化方法下,全桥子模块中关断电阻为实际值时该排序算法依然适用,并将该证明方法拓展到了对半桥型MMC戴维南等效模型线性排序算法的证明中。通过更具一般性的证明分析了该线性排序算法的本质机理,指出该算法分组的依据并分析了该算法对基于其他拓扑的MMC戴维南等效模型的适用性及其优缺点。

Linear Ranking Algorithm for Full-bridge MMC Equivalent Models

Modular multilevel converter(MMC) has been applied worldwide to build the high-voltage direct current(HVDC) grid with renewable power integration. With the development of the DC grid, full-bridge MMC gains increasing attention. However, current MMC equivalent models are still low in efficiency while simulating the MMCs with high voltage levels-based DC grids due to the complexity of ranking algorithm. Previous research proposed a linear ranking algorithm for MMC based on full-bridge sub-module(FBSM) by adopting the turn-off resistance of the IGBT switches of ideal zero conductance and backward Euler method. This paper theoretically proves that in different integration methods, the linear ranking algorithm is also valid with the typical two-value switches used in the FBSM based MMC models on the basis of nested fast and simultaneous solution. The method can also be used to prove MMC model based on half bridge sub-module(HBSM). In addition, this paper also analyzes the essential principle of the linear ranking algorithm and points out the grouping principle of the algorithm. Moreover, this paper analyzes the advantages and disadvantages and applicability of the ranking algorithm.