Analysis of the Impact on Modular Multilevel Converter with Circulating Current Injection under Unbalanced Grid Voltage
Shi Enze1, Wu Xuezhi1, Jing Long1, Jiang Jiuchun1,2, Li Jingke2
1. National Active Distribution Network Technology Research Center Beijing Jiaotong University Beijing 100044 China; 2. Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100042 China
Abstract：Based on the switching function, the 3D-graph analysis and the fitting method, this paper proposes a reasonable circulating current injection method to reduce the peak value of arm current and the capacitor voltage ripple of the module under unbalanced grid voltage. The impacts of circulating current injection on the peak value and root mean square value of the arm current as well as the capacitor voltage ripple are analyzed. The best angle to minimize the peak value of arm current and the formula to limit circulation injection amplitude under different conditions are obtained, and the best angle to minimize the capacitor voltage ripple and its limited formula of amplitude are further obtained. Considering the tolerance of current and voltage in sub module, a circulating current injection method is proposed, which can limit peak value of arm current as well as the capacitor voltage ripple. Finally, the correctness of the analysis and the effectiveness of the proposed method are verified in Matlab/Simulink simulation and the experimental platform.
施恩泽, 吴学智, 荆龙, 姜久春, 李金科. 网压不平衡下环流注入对模块化多电平换流器的影响分析[J]. 电工技术学报, 2018, 33(16): 3719-3731.
Shi Enze, Wu Xuezhi, Jing Long, Jiang Jiuchun, Li Jingke. Analysis of the Impact on Modular Multilevel Converter with Circulating Current Injection under Unbalanced Grid Voltage. Transactions of China Electrotechnical Society, 2018, 33(16): 3719-3731.
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2018, Vol. 33 
