Cross‐coupling over frequency and sequence in impedance modelling of grid‐connected inverter. Issue 13 (19th December 2017)

• Record Type: Journal Article
• Authors: Xu, Yunyang; Nian, Heng; Xu, Guodong; Qiu, Jixing
• Is Part Of: Journal of engineering. Volume 2017:Issue 13(2017)
• Page Start: 990
• Page End: 995
• Publication Date: 2017-12-19
• Subjects: invertors -- electric admittance -- phase locked loops -- stability -- power grids -- matrix algebra -- electric current control; grid‐connected inverter -- grid‐inverter system stability analysis -- sequence impedance models -- negative‐sequence subsystems -- asymmetric current regulators -- cross‐coupling -- positive‐sequence subsystems -- analytical admittance matrix model -- soft dc bus -- PLL -- phase locking loop; Engineering -- Periodicals; Engineering; Electronic journals; Periodicals; 620.005
• DOI: 10.1049/joe.2017.0478
• Languages: English
• ISSNs: 2051-3305

Abstract

Abstract : Impedance‐based stability theory is an effective technique in grid‐inverter system stability analysis. In existed research based on this theory, sequence impedance models are assumed to have linear behaviour under small‐signal operation, and the grid‐inverter system can be decoupled into positive‐ and negative‐sequence subsystems. However, this may lead to wrong conclusions if there is cross‐coupling over frequency and sequence, which can be caused by phase locking loop (PLL), asymmetric current regulators, and soft dc bus. Here, the cross‐coupling will be analysed, and a 2 × 2 analytical admittance matrix model of grid‐connected inverter will be derived and validated, which can describe the cross‐coupling caused by PLL and asymmetric current regulators. The influence of the cross‐coupling on system stability is also discussed.