Abstract：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.
荣飞, 陈盼庆, 黄守道, 姜燕. 一种减少电压互感器的模块化多电平换流器分组控制策略[J]. 电工技术学报, 2017, 32(18): 186-195.
Rong Fei, Chen Panqing, Huang Shoudao, Jiang Yan. Sub-Module Grouping Strategy for Reducing the Number of Voltage Sensors in Modular Multilevel Converters. Transactions of China Electrotechnical Society, 2017, 32(18): 186-195.
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2017, Vol. 32 
