Voltage Grid Supporting by Using Variable Structure Adaptive Virtual Impedance for LCL-Voltage Source Converter DG Converters. - Thales Queiroz Fonsêca; Ricardo Lúcio de Araujo Ribeiro; Thiago de Oliveira Alves Rocha; Flávio B. Costa 001; Josep M. Guerrero (IEEE Trans. Ind. Electron., 2020)