Output Admittance Synthesizer for Synchronverters

This article proposes an “output admittance synthesizer” (OAS), a feedback block that enables the synchronverter (SV) to have specific values of output admittance (modulus and phase), at specified harmonic frequencies (and sequences) of the fundamental frequency of the grid voltage (including±1). The sequence discrimination enables the SV to have two different admittances at each frequency: A positive sequence and a negative sequence admittance. This feature is of interest for both treating harmonics and imbalance of the voltage at the point of common coupling. Additionally, using the OAS allows to place the closed loop poles of the resulting feedback system at arbitrary locations.