针对模块化多电平矩阵变流器（modular multilevel matrix converter，M3C）运行过程中9个桥臂直流侧电容电压不平衡以及子模块（sub-module，SM）电容电压波动等问题，提出了针对桥臂均压的环流控制策略。建立了M3C输入侧、输出侧的数学解耦模型，并通过对M3C各个桥臂功率的分析设计出桥臂电容电压平衡分级控制策略消除了M3C桥臂电容电压在f_m≈0和f_m=f_g（f_m、f_g分别为输入侧和输出侧频率）电容电压纹波低频交流分量造成的剧烈震荡；在RT-LAB平台上搭建了M3C半物理实验系统，并模拟了正常工况、低频工况和特殊工况下的系统运行情况。实验结果表明所提桥臂均压控制策略效果好，直流侧电容电压波动范围小，输出电能质量更佳。

Addressing issues such as unbalanced DC-side capacitor voltage of the nine bridge arms and sub-module (SM) capacitor voltage fluctuations during the operation of the modular multilevel matrix converter (M3C), a circulating current control strategy for bridge arm voltage balancing is proposed. A mathematical decoupling model for both the input and output sides of the M3C is established. Through the analysis of the power of each bridge arm in the M3C, a hierarchical control strategy for bridge arm capacitor voltage balancing is designed, eliminating severe oscillations caused by low-frequency AC components of capacitor voltage ripple under the conditions f_m≈0 and f_m=f_g. A semi-physical experimental system for the M3C is built on the RT-LAB platform, and system operation under normal, low-frequency, and special operating conditions is simulated. Experimental results show that the proposed bridge arm voltage balancing control strategy performs well, with small fluctuation range of DC-side capacitor voltage and better output power quality.