@Article{ee.2023.025171, AUTHOR = {Hui Fang, Jingsen Zhou, Haozheng Wang, Yanxu Wang, Hongji Xiang, Yechun Xin}, TITLE = {Harmonic State-Space Based AC-Side Impedance Model of MMC and High Frequency Oscillation Characteristics Analysis}, JOURNAL = {Energy Engineering}, VOLUME = {120}, YEAR = {2023}, NUMBER = {4}, PAGES = {831--850}, URL = {http://www.techscience.com/energy/v120n4/51683}, ISSN = {1546-0118}, ABSTRACT = {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.}, DOI = {10.32604/ee.2023.025171} }