The Inrush Current Characteristics and Control Strategies of Hybrid-Modular Multilevel Converter Systems During Start-Up Processes
Luo Yongjie1, Pu Yi1, Song Yonghui1, Yi Lizheng2
1. State Key Laboratory of Power Transmission Equipment & System Security and New TechnologyChongqing University Chongqing 400044 China; 2. State Grid Chongqing Electric Power Company Chongqing 400014 China
Abstract：Start-up control is the basic conditions of modular multilevel converter (MMC) system operation. However, the capacitor voltages of hybrid-MMC, which consists of full-bridge sub-modules and half-bridge sub-modules, are relatively low and unbalanced after precharge, resulting in inrush current and over modulation. The precharge voltage characteristics of hybrid-MMC and the equivalent circuit are analyzed, based on the converter topology. A method to calculate the precharge voltage of two kinds of sub-modules, respectively, is presented. Then, based on the capability of producing negative level of full-bridge sub-modules, an ac-side start-up control strategy is proposed in this paper, to suppress the inrush current and over modulation. The theory analysis and the proposed strategy are demonstrated by the PSCAD/EMTDC simulation.
罗永捷, 蒲羿, 宋勇辉, 易力峥. 混合型模块化多电平换流器启动冲击电流特性分析及控制策略[J]. 电工技术学报, 2020, 35(zk1): 49-59.
Luo Yongjie, Pu Yi, Song Yonghui, Yi Lizheng. The Inrush Current Characteristics and Control Strategies of Hybrid-Modular Multilevel Converter Systems During Start-Up Processes. Transactions of China Electrotechnical Society, 2020, 35(zk1): 49-59.
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2020, Vol. 35 
