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低频运行时模块电容电压的大幅波动限制了模块化多电平换流器(modular multilevel converter,MMC)在电机驱动领域的应用,该文针对有谐振滤波电路的MMC结构,提出一种合理的低频控制方法.在分析谐振滤波电路特性的基础上,利用谐振滤波电路对相阻抗的改变,并通过参数设计,同时实现 MMC 额定频率运行时二倍频环流抑制和低频运行时高频环流控制电压最低.该方法无需注入频率混合及频率变化的环流,可降低环流控制器设计难度,同时相阻抗在串联谐振频率处压降最小,提高了高频共模电压的可利用范围.为实现对交直流混合环流指令的无差跟踪,引入比例–积分–谐振控制以准确抵消导致电容电压剧烈波动的无功功率交换,抑制模块电容电压的波动,同时维持模块电容电压均值的稳定,保证MMC低频运行的安全性和可靠性.最后通过实验验证了理论分析和控制方法的准确性与有效性.“,”Due to the sub-module capacitance voltage fluctuation when operating at low frequency, MMCs are limited in the application of motor drive, and a reasonable control method is the premise to guarantee the security and stable operation of MMC in the low frequencyoperating condition. In view of MMC with tuned filter circuit, an adaptable low frequency control strategy is proposed. On the basis of detailed characteristic analysis for tuned filter, by taking advantage of the change of bridge impedance caused by tuned filter,the 2nd frequency circulating current can be well restrained at rated frequency and the minimum voltage used to control high frequency circulating current can be achieved at low frequency by use ofreasonable parameters. The high frequency circulating currents with mixing and variable frequency are not necessary in proposed method, which simplifies the design of circulating current controller, and available range of the high common-mode voltage will be increased thanks to minimal voltage drop on bridge impedance at high fixed frequency. Zero error tracking with the reference ofAC&DC hybrid circulating current can be realized by utilizing proportional integral resonant (PIR) control, which not only maintains the average voltage of the capacitance, but also effectively counteracts the fluctuation in capacitor voltagedue to the reactive power interchange, leading to a reliable system at low frequency range.The accuracy and effectiveness of the analysis and method are verified by prototype experiment.