Comparative Study of Small-Signal Stability Under Weak AC System Integration for Different VSCs

Voltage source converters (VSCs) with self-commutation ability are suitable for interconnecting weak ac systems. This article conducts a comparative study of the small-signal stability characteristics three typical VSCs, namely, two-level VSCs (TL-VSCs), half-bridge modular multilevel (HB-MMCs), and hybrid MMCs (HY-MMCs), under system integration special consideration on both inverter rectifier operation. The frequency responses based impedance models compared using frequency-domain analysis. oscillation frequencies mainly participated state variables unstable modes root locus participation factor analysis in time domain. Proper parameter retuning approaches enhancement proposed. above is adequately validated by electromagnetic simulations.