Low‐frequency harmonic resonance analysis and suppression method of modular multilevel converter. Issue 4 (1st April 2018)

• Record Type: Journal Article
• Authors: Yue, Yufei; Xu, Qianming; Shuai, Zhikang; He, Zhixing; Guo, Peng; Li, Yan; Luo, An; Shen, John
• Is Part Of: IET power electronics. Volume 11:Issue 4(2018)
• Page Start: 755
• Page End: 763
• Publication Date: 2018-04-01
• Subjects: harmonics suppression -- HVDC power convertors -- voltage‐source convertors -- HVDC power transmission -- power system stability -- feedback -- closed loop systems -- feedforward -- power transmission control; low‐frequency harmonic resonance analysis -- modular multilevel converter -- high‐voltage DC transmission systems -- MMC stability -- MMC equivalent model -- intrinsic harmonic resonance -- potential harmonic resonance -- low‐frequency harmonic resonance suppression method -- circulating current suppressing method -- active damping -- internal damped characteristic improvement -- control effectiveness enhancement -- circulating current reference -- dual feedback closed‐loop control -- power feedforward loop -- MMC reasonable damping characteristic -- MMC‐HVDC system -- RT‐LAB simulator platform; Power electronics -- Periodicals; 621.31705
• DOI: 10.1049/iet-pel.2017.0693
• Languages: English
• ISSNs: 1755-4535

Abstract

Abstract : Modular multilevel converters (MMCs) become increasingly attractive in high‐voltage dc (HVDC) transmission systems. However, the internal poorly damped characteristic can easily lead to low‐frequency harmonic resonance, affecting the stability of MMC. In this study, the equivalent model of MMC is established to reveal the low‐frequency harmonic resonance, including intrinsic harmonic resonance and potential harmonic resonance. To suppress the harmonic resonance, a circulating current suppressing method based on active damping is proposed to improve the internal damped characteristic. In order to enhance the control effectiveness, the circulating current reference is modified through a dual feedback closed‐loop control involving arm voltages and currents as well as the power feedforward loop in the proposed suppression strategy. Proper parameters are designed to apply the reasonable damping characteristic of MMC. Finally, the proposed method is implemented and verified with an MMC‐HVDC system in the RT‐LAB simulator platform.