Authors

Liang Yuan, Mingxin Hu, Mei Su, Zhangjie Liu, Yao Sun, Zhao Yang Dong

Abstract

Grid-forming (GFM) inverters are pivotal for enhancing the stability and resilience of power systems with high penetration of renewable energy, positioning them as a key technology for future grids. Consequently, the transient stability of GFM inverters in grid-connected systems has garnered significant research interest. Although numerous strategies have been proposed to enhance transient stability, most of them are designed for single-input single-output (SISO) systems. When resistance and reactive power control are taken into account, the GFM system exhibits strong coupling between active and reactive power, thereby becoming a multiinput multioutput (MIMO) system. Consequently, these strategies are difficult to apply effectively to such MIMO system scenarios. Moreover, some strategies rely on real-time grid voltage measurements during faults, which limits their practical applicability. To address these limitations, this article proposes a multiinput transient stability enhancement strategy for GFM inverters based on port-controlled Hamiltonian (PCH) theory, which explicitly incorporates line resistance and RPC dynamics. First, a PCH model of the grid-connected GFM system is established for a resistive-inductive network, integrating the dynamics of RPC. In contrast to conventional Lyapunov energy functions, the proposed Hamiltonian function provides a more accurate estimation of the attraction region, offering a more reliable tool for transient stability assessment for MIMO GFM system. Then, based on energy reshaping method, a control strategy is developed to enhance transient stability by adjusting both active and reactive power references during faults via state-variable feedback. Rigorous stability analysis demonstrates that the closed-loop system is asymptotically stable at the desired equilibrium point, even under severe voltage sags, without grid voltage information. Finally, the effectiveness of the proposed control strategy and the theoretical analyses are validated through hardware experiments.

Citation

  • Journal: IEEE Transactions on Industrial Electronics
  • Year: 2026
  • Volume:
  • Issue:
  • Pages: 1–13
  • Publisher: Institute of Electrical and Electronics Engineers (IEEE)
  • DOI: 10.1109/tie.2026.3690734

BibTeX

@article{Yuan_2026,
  title={{PCH Theory-Based Energy Reshaping Control for Transient Stability Enhancement of Grid-Connected Grid-Forming Inverters}},
  ISSN={1557-9948},
  DOI={10.1109/tie.2026.3690734},
  journal={IEEE Transactions on Industrial Electronics},
  publisher={Institute of Electrical and Electronics Engineers (IEEE)},
  author={Yuan, Liang and Hu, Mingxin and Su, Mei and Liu, Zhangjie and Sun, Yao and Dong, Zhao Yang},
  year={2026},
  pages={1--13}
}

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