Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title Maximum Modulation Index of VSC HVDC based on MMC Considering Compensation Signals and AC Network Conditions
Authors Chan-Ki Kim ; Negesse Belete Belayneh ; Chang-Hwan Park ; Jang-Mok Kim
DOI 10.6113/TKPE.2020.25.1.61
Page pp.61-67
ISSN 1229-2214
Keywords MMC HVDC system; Modulation index; AC network system
Abstract This study deals with the modulation index (MI) of a voltage source converter (VSC) HVDC system based on a modular multilevel converter (MMC). In the two-level converter, the purpose of the MI is to maximize the achievable AC voltage of the converter from a fixed DC voltage. Unlike that in a two-level converter, the MI in the MMC topology plays a role in making the converter a voltage source using a capacitor. The circulating current in the MMC distorts the AC voltage reference, and the distortion affects the MI. In addition, the AC network conditions, such as AC voltage variation and reactive power, affect the MI. Therefore, the MI should be optimized with consideration of internal and external factors. This study proposes a method to optimize the MI of an MMC HVDC system.