重点研究了桥臂交替导通多电平换流器(AAMC)的电容电压平衡控制.首先阐述了AAMC的运行特性和工作原理；其次基于子模块充放电的基本原则,提出了适用于AAMC的改进最近电平调制策略,根据桥臂电流方向和子模块电容排序结果确定子模块的投切状态;并通过引入最大电压波动系数优化选择子模块投切时机,降低了开关频率并减少了损耗.在PSCAD/EMTDC中搭建了每桥臂10个子模块的模型,时域仿真结果表明,所提出的平衡控制策略能够满足电容电压均衡.%The capacitor voltage balancing control of AAMC(Alternate-Arm Multilevel Converter) is studied. Its operating characteristics and working principle are studied and an improved nearest level control strategy is proposed based on the SM(SubModule) charging and discharging. The state of SM is determined according to the polarity of arm current and the order of capacitor voltage. The maximum voltage fluctuation coefficient is applied to optimize the switching time for lowering the switching frequency and reducing the loss. A model of AAMC with 10 SMs per arm is established in PSCAD/EMTDC and the simulative result verifies the effectiveness of the proposed control strategy.
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