Voltage Grid Supporting by Using Variable Structure Adaptive Virtual Impedance for LCL-Voltage Source Converter DG Converters

• Published in: IEEE transactions on industrial electronics (1982) Vol. 67; no. 11; pp. 9326 - 9336
• Main Authors: Fonseca, Thales Queiroz, Ribeiro, Ricardo L. A., Rocha, Thiago de Oliveira Alves, Costa, Flavio Bezerra, Guerrero, Josep M.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-11-2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive virtual impedance; Capacitance; Converters; distributed generation (DG); droop control; Electric potential; Impedance; LCL-VSC; Microgrids; Power flow; Power rating; Radio frequency; Reactive power; Transfer functions; Variable structure control; Voltage; Voltage control
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2019.2952784

This article proposes a voltage grid supporting applied for DGs based on LCL-VSC to control the delivered power flow and improve the point of common coupling (PCC) voltage regulation. A variable structure adaptive virtual impedance (VS-AVI) imposes the required DG impedance for achieving the system voltage requirements, considering the power rating of the DG converter. Differently of the solutions presented in the literature, the proposed VS-AVI employs adaptive piecewise linear droop function and dead zone for emulating the virtual capacitance for shaping the equivalent grid impedance and achieves the required PCC voltage regulation. Simulation and experimental results validate the proposed VS-AVI and demonstrate its effectiveness.