Understanding the role of VSC control strategies in the limits of power electronics integration in AC grids using modal analysis

In this article, the interactions between AC grid and existing VSC control modes are analyzed. First, three modes, namely grid-feeding, grid-supporting grid-forming, compared with each other in order to assess VSC/grid coupling level. Then, underscore growing role of VSCs transmission systems, an elementary benchmark network is considered. It includes equivalent SM (Synchronous Machine), a VSC, load line varying electrical distance. Thereafter, modal analysis conducted on model study different controls dynamics using Matlab/Simulink environment. The converter penetration rate represented by variable power ratio machine, while distance RL dynamic impedance. This approach makes it possible stability limits share imposed system strength. Negative identified recommendations for novel strategies proposed. Besides, influence AVR grid-forming as well PLL-related issues grid-feeding or shown be key limiting factors increasing PE-based sources.