针对模块化多电平换流器(MMC)需要配置大量电压互感器的问题,提出一种减少电压互感器的分组控制策略.该控制策略将每个桥臂的2N个子模块按照20,21,22,…,2N?1,20分成N+1个子模块组.将每组的子模块作为一个整体,开关状态保持一致,并且配备一个电压互感器,用于测量每组的电容电压.根据这种结构设计相应的电容电压平衡控制方法、均压控制方法和调制方法.电容电压平衡控制采用PI调节器稳定各组子模块的电容电压;均压控制用来保持组间子模块电压平均值均衡;调制方法用来确定各个模块组的通断状态.该分组方法极大地减少了电压互感器的数量,降低MMC系统的造价.最后通过在Matlab/Simulink平台上搭建三十三电平的三相MMC仿真模型进行证明,并搭建九电平单相MMC实验平台,进行实验验证,结果表明了该分组控制策略的有效性.%Modular multilevel converter (MMC) needs a large number of voltage sensors. Thus, this paper presents a grouping control strategy to reduce voltage sensors. This control strategy divides the 2N sub-modules into N+1 groups according to the sequence of 20, 21, 22,…, 2N?1, 20. Each group of sub-modules is regarded as an entirety, whose switch state must remain the same. A voltage sensor is equipped to detect the capacitance voltage of each group. On the basis of this structure, the corresponding methods of capacitor voltage balance control, average voltage control and modulation are proposed. In the method of capacitor voltage balance control, PI regulator is utilized to stabilize the voltage of each sub-module in all groups; the average voltage control balances the voltage of each sub-module; modulation method is to determine the switch state of each sub-module. This strategy reduces a great number of voltage sensors as well as the cost of MMC system. Finally, the case studies are performed on a 33-level three-phase MMC in Matlab/Simulink, which prove the accuracy of this strategy. Meanwhile, a 9-level single-phase MMC laboratory prototype is built to verify the effectiveness of this strategy.
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