Influence of voltage feed-forward control on small-signal stability of grid-tied inverters

In balanced three-phase systems, source impedance and load admittance matrices in the synchronous rotating (d-q) frame can be used to determine system small-signal stability based on the Generalized Nyquist stability Criterion (GNC). For grid-tied inverters, voltage feed-forward control (VFFC) is widely used due to its fast transient dynamics. Through modeling the d-q frame admittances of three-phase grid-tied inverters with voltage feed-forward control, this paper illustrates instability mechanism and proposes some possible solutions. Simulation and experimental results verify the analysis.