<p>Grid-forming voltage-source converters (VSCs) tend to suffer
from sideband oscillations in stiff grids. Conventional state-space eigenvalue
analysis or impedance-based stability analysis based on generalized Nyquist
stability criterion can only analyze how specific control parameters affect the
overall system stability, which ends up with less insight into a controller
design-oriented analysis. To tackle this challenge, this article starts with the
impedance modeling and stability analysis of grid-forming VSCs in stiff grids.
Then, an impedance decomposition approach to characterizing the impacts of
multiple control loops is proposed, which benefits in a controller
design-oriented analysis for stability enhancement. Finally, simulation and
experimental results are provided to validate the approach.</p>
Impedance Decomposition for Design-Oriented Analysis of Grid-Forming Voltage-Source Converters
