TY  - EJOU
AU  - Fang, Hui 
AU  - Zhou, Jingsen 
AU  - Wang, Haozheng 
AU  - Wang, Yanxu 
AU  - Xiang, Hongji 
AU  - Xin, Yechun 

TI  - Harmonic State-Space Based AC-Side Impedance Model of MMC and High Frequency Oscillation Characteristics Analysis
T2  - Energy Engineering

PY  - 2023
VL  - 120
IS  - 4
SN  - 1546-0118

AB  - Recently, high-frequency oscillation of the modular multilevel converter (MMC) based high-voltage direct current (HVDC) projects has attracted great attentions. In order to analyze the small-signal stability, this paper uses the harmonic state-space (HSS) method to establish a detailed frequency domain impedance model of the AC-side of the HVDC transmission system, which considers the internal dynamic characteristics. In addition, the suggested model is also used to assess the system's high-frequency oscillation mechanism, and the effects of the MMC current inner loop control, feedforward voltage links, and control delay on the high-frequency impedance characteristics and the effect of higher harmonic components. Finally, three oscillation suppression schemes are analyzed for the oscillation problems occurring in actual engineering, and a simplified impedance model considering only the high-frequency impedance characteristics is established to compare the suppression effect with the detailed impedance model to prove its reliability.
KW  - Modular multilevel converter; impedance modeling; small-signal stability; suppression strategy

DO  - 10.32604/ee.2023.025171