模块化多电平换流器稳态运行特性的解析分析

An Analytical Method for Analysis on Steady-State Operating Characteristics of Modular Multilevel Converter

为了实现模块化多电平换流器装置的主回路分析和参数设计,建立模块化多电平换流器稳态运行特性的准确解析分析方法十分必要。文章基于开关函数分析方法建立了子模块各电气量之间耦合关系,可以直接得到换流器的主要电气量解析表达式,计算过程相对比较简单。事先计算出二倍频环流分量的幅值和相位,并在后续计算过程中考虑二倍频环流的影响,使计算结果更为准确。通过将解析计算结果分别与仿真和物理试验结果进行对比,验证了所提方法的有效性和准确度。

To implement its main circuit analysis and parameter design,it is necessary to establish an analytical method for accurate analysis on steady-state operating characteristics of modular multilevel converter（MMC）.Based on the switching function analysis,the coupling relationships among such electric quantities as arm current,capacitor current, capacitor voltage and circulating current in sub-modules are built, thus analytical expressions of principal electric quantities of MMC can be directly attained and the computation is relatively simpler.The amplitude and phase of the doubling-frequency circulating current are calculated in advance,and in follow-up calculation the influence of the doubling-frequency circulating current is taken into account to make the calculation results more accurate.The results of analytical calculation are compared with simulation results and experimental results respectively,thus the feasibility and accuracy of the proposed method are verified.