부산대학교 도서관

This paper proposes an online grid impedance estimation method for AC Grids under the presence of grid-tied converters. A novel modelling approach in the $\alpha,\beta,0$ reference frame is proposed, including the relationship with the instantaneous power theory. The proposed modelling framework considers both balanced and unbalanced conditions and operation in the four quadrants. For the impedance identification, a Pulsed Signal Injection (PSI) approach together with a Recursive Least Square (RLS) algorithm is used. The proposed modelling and identification method is thoroughly evaluated by simulation and experimental results. The work presents a contribution for the optimization of the distribution grid operation with high-dynamic impedance changes due to the integration of distributed resources.