Nonlinear Behavior and Reduced-Order Models of Islanded Microgrid

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)9212-9225
Journal / PublicationIEEE Transactions on Power Electronics
Issue number8
Online published16 Mar 2022
Publication statusPublished - Aug 2022


An islanded microgrid consisting of grid-forming converters, being a high-order nonlinear system, exhibits rich nonlinear dynamical phenomena. The use of appropriate reduced-order models offers useful physical insights into the behavior of the system without the need for excessive computational resources. In this paper, we derive a number of reduced-order models capable of describing the slow-scale dynamics of an islanded microgrid comprising a number of grid-forming converters. It is shown that slow-scale Hopf and homoclinic bifurcation behaviors arise from the stability of the voltage loops of grid-forming converters, and are unrelated to the transmission network dynamics. Therefore, omitting the network dynamics does not affect the accuracy of reduced-order models in representing the slow-scale dynamics of the system. This is especially beneficial for modeling the microgrid with a complex transmission network. Furthermore, on this basis, all inner loops can be omitted when studying saddle-node bifurcation, leading to the development of power-flow-based reduced-order models. Finally, the stability of an islanded microgrid with a complex transmission network is evaluated.

Research Area(s)

  • Bifurcation, Converters, grid-forming converter, homoclinic bifurcation, Hopf bifurcation, microgrid, Microgrids, Oscillators, Power conversion, Power system stability, Reduced order systems, reduced-order model, saddle-node bifurcation