Electronic Science and Technology ›› 2022, Vol. 35 ›› Issue (1): 80-86.doi: 10.16180/j.cnki.issn1007-7820.2022.01.013

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Control Strategy of Modular Multilevel Converter Under Unbalanced Grid Voltage

NIU Shuaichen1,WANG Fuzhong1,HAN Yaofei2,HE Guofeng2,NIU Yeke1   

  1. 1. School of Electrical Engineering and Automation,Henan Polytechnic University,Jiaozuo 454000,China
    2. School of Electrical and Control Engineering,Henan University of Urban Construction, Pingdingshan 467036,China
  • Received:2020-09-07 Online:2022-01-15 Published:2022-02-24
  • Supported by:
    National Natural Science Foundation of China(61503122)


When the power grid is in a voltage unbalanced state, a circulating current will be generated inside the MMC. The positive sequence, negative sequence and zero sequence components of double frequency exist in the circulating current, which increases the instability of the system. In view of the problem of MMC double-frequency circulating current suppression under unbalanced power grids, this study proposes a circulating current suppression strategy based on a linear active disturbance rejection controller. According to the instantaneous power theory, the quantitative relationship of the circulating current parameters is derived. On this basis, the circulating current controller based on the linear active disturbance rejection control strategy is designed to suppress the circulating current. Finally, the proposed control strategy is simulated by MATLAB/Simulink software. The simulation results show that the control strategy can effectively restrain the circulation and increase the stability of the system.

Key words: unbalanced grid voltage, MMC, ADRc, circulation, MATLAB/Simulink, double frequency, circulation suppression, simulation model

CLC Number: 

  • TP202