Characteristics analysis of MMC in arm asymmetrical operation and control strategy under submodule fault

被引:0
作者
Li K. [1 ]
Zhang Z. [1 ]
Liu Z. [1 ]
Qi X. [1 ]
Yu X. [1 ]
Wang Z. [1 ]
机构
[1] School of Electrical Engineering, Shandong University, Jinan
来源
Gaodianya Jishu/High Voltage Engineering | 2016年 / 42卷 / 10期
基金
中国国家自然科学基金;
关键词
Asymmetrical operation; Circulating current control; Fault control strategy; Modular multilevel converter; Sub-module fault;
D O I
10.13336/j.1003-6520.hve.20160926005
中图分类号
TP [自动化技术、计算机技术];
学科分类号
0812 ;
摘要
Sub-module fault is one of the common fault types of MMC, and MMC will turn into arm asymmetrical operation state after the faulty SMs have been bypassed. In order to ensure the stable operation of MMC in this state, the characteristics of MMC under arm asymmetrical operation are theoretically analyzed in detail; and a complete set of control strategy under SM fault is proposed, including a faulty SM localization method based on capacitor comparison and a method to suppress the fundamental component of circulating current based on PR controller. And an MMC-HVDC simulation system with 21 levels is established in the PSCAD/EMTDC software environment to simulate and prove the theoretical analysis and the control strategy under SM fault. The results show that the fundamental component of phase current will no longer distribute evenly between upper and lower converter arms under arm asymmetrical operation; in addition, fundamental component and the 3rd harmonic component will appear in circulating current, and the 2nd harmonic components which already exist will increase slightly. In the meantime, the SM localization method can identify multiple faulty SMs within one fundamental period; while the additional components of the circulating current in asymmetrical operation state can be well suppressed. The simulation results are consistent with the theoretical analyses, which proves the validity of the theoretical analysis and the effectiveness of the proposed control strategy. © 2016, High Voltage Engineering Editorial Department of CEPRI. All right reserved.
引用
收藏
页码:3059 / 3067
页数:8
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