Mapping of Dynamics between Mechanical and Electrical Ports in SG-IBR Composite Grids

Yitong Li, Yunjie Gu, Tim Green

Research output: Contribution to journalArticlepeer-review

4 Citations (SciVal)
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Power grids are traditionally dominated by synchronous generators (SGs) but are currently undergoing a major transformation due to the increasing integration of inverter-based resources (IBRs). The state space method with transparent apparatus models can be readily used. However, models of IBRs are usually not disclosed by manufacturers. Alternatively, the port-based approach represents dynamics by input-output transfer functions without exposing internal states. These transfer functions at various ports are normally configured with a particular focus: an SG-dominated grid is traditionally analyzed in a \textit{mechanical-centric} view which ignores fast electrical dynamics and focuses on the torque-speed dynamics, whereas the emergent IBR-dominated grid usually takes an electrical-centric view which focuses on the voltage-current interaction. In this article, a new perspective called the port-mapping method is proposed to combine these two views. Specifically, the mechanical dynamics are mapped to the electrical impedance seen at the electrical port; and the electrical dynamics are also mapped to the torque coefficient seen at the mechanical port. The bidirectional mapping gives additional flexibility and insights to analyze the sub-system interactions in whole-system dynamics and guide the tuning of parameters. Application of the proposed method is illustrated in three cases with increasing scales.

Original languageEnglish
Pages (from-to)3423 - 3433
JournalIEEE Transactions on Power Systems
Issue number5
Early online date11 Jan 2022
Publication statusPublished - 30 Sept 2022


  • Composite Power System
  • Electrical-Mechanical Two-Port Network
  • Impedance
  • Inverter Based Resource
  • Oscillators
  • Port-Mapping
  • Power system dynamics
  • Power system stability
  • Rotors
  • Synchronous Generator
  • Torque
  • Transfer functions

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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