中文摘要：

作为模块化多电平换流器（MMC）的重要组成部分,位于换流器桥臂的桥臂电抗器能够起到抑制换流器输出电流谐波以及限制暂态和故障电流的作用,其电感值的选取对于MMC的运行特性极为关键。文中提出了一种能够抑制交流侧电流波动量的桥臂电抗器值的设计方法。通过对MMC拓扑结构和工作原理的分析,对桥臂电抗器进行了简化等效,详细推导了等效电感值与交流侧电流波动量之间的关系,得出了一定交流侧电流波动量条件下的等效电抗器最小值的四阶方程,并利用MATLAB对方程求解,最终得到对应的桥臂电抗器值的下限值。在PSCAD/EMTDC仿真环境下搭建了双端21电平MMC直流输电系统模型,对设计方法的可行性和准确性进行了验证。仿真结果表明,设计的桥臂电抗器能够有效抑制交流谐波电流,且计算值与实验值基本吻合。

英文摘要：

As an important part of the modular multilevel converter（MMC）,the bridge arm reactor is able to restrain output harmonic current and transient current of converters.The determination of its inductance is crucial to optimizing the operating characteristics of MMC.A bridge arm reactance design method considering restraining the AC side current fluctuation is proposed.The arm reactor is properly simplified based on an analysis of the topological structure and working principle of MMC.The relationship between the equivalent inductance value and the AC side current fluctuation is detailedly derived,which is presented as a fourth-order equation about the equivalent reactance under the condition of a definite amount of the AC side current fluctuation.The equation is solved by MATLAB and the lower limit value of the bridge arm reactance is obtained.The feasibility and veracity of the proposed design method are verified by building a simulation model of 21-level MMC in PSCAD/EMTDC.The results of simulation show that the designed bridge arm reactor can effectively reduce the harmonic current,with the calculated values basically in agreement with the experimental ones.