中文摘要：

对比采用不同调制策略时模块化多电平换流器输出波形的特性。模块化多电平换流器的调制策略，根据是否需要对子模块电容电压排序，可分为计算投入子模块个数调制策略和载波相移调制策略2类。在同一电平数下，采用不同调制策略会对模块化多电平换流器输出波形的各次谐波分布和谐波畸变率产生明显影响。当电平数升高时，不同调制策略对谐波畸变率的减少量也不同。

英文摘要：

A enmparison is made in this paper of various modulation methods in terms of the output characteristics of the modular muhilevel converter （MMC）. The modulation methods can be divided into submodule unified method and carrier phase shifted method based on the neeessity of sorting the capacitor voltages of submodules. For a given voltage level, the harmonic distribution and the total harmonic distortion （THD） of the MMC output are obviously affected by the modulation methods. With increasing of the voltage levels, the THD reduction is varied with different modulation methods.