To address the issue of medium/high-frequency oscillations in renewable energy stations
an improved control strategy for grid-forming converters is proposed. First
based on the harmonic linearization method
the sequence impedance model of the converter is established
and the influence of main circuit parameters and control parameters on the medium/high-frequency impedance characteristics of the converter is analyzed. Second
the decentralized stability criterion is applied to analyze system stability
reducing the conservatism and computational complexity of traditional stability analysis. Furthermore
the proposed improved grid-forming converter is applied to systems with a low proportion of grid-forming converters. Compared with traditional virtual synchronous generators
it demonstrates superior performance in suppressing medium/high-frequency oscillations. Finally
the effectiveness and correctness of the proposed method and analysis results are validated using real-time digital simulation software.
SUBRAMANIAN S B, Varma R K, VANDERHEIDE T. Impact of grid voltage feed-forward filters on coupling between DC-Link voltage and AC voltage vontrollers in smart PV solar systems [J ] . IEEE Transactions on Sustainable Energy,2020,11(1):381-390.
MATEU-BARRIENDOS E,ALICAN O,RENEDO J,et al. Power oscillation damping controllers for grid-forming power converters in modern power systems [J ] . IEEE Transactions on Power Systems,2025,40(6):5130-5143.
YU Y,GUAN Y J,KANG W F,et al. Active damping of grid-forming voltage-source converter using fractional-order regulators [J ] . IEEE Transactions on Industrial Electronics,2025,72(8):8107-8118.
HE X Q,GENG H,XI J B,et al. Resynchronization analysis and improvement of grid-connected VSCs during grid faults [J ] . IEEE Journal Of Emerging And Selected Topics In Power Electronics,2021,9(1):438-450.
KONG L C,TANG H G,WU C,et al. Analysis and damping of subsynchronous oscillations for cascaded grid-forming converters considering DC-Link dynamics [J ] . IEEE Transactions on Power Electronics,2025,40(1):2284-2299.
HUANG L B,XIN H H,WANG Z,et al. A virtual synchronous control for voltage-source converters utilizing dynamics of DC-Link capacitor to realize self-synchronization [J ] . IEEE Journal of Emerging and Selected Topics in Power Electronics,2017,5(4):1565-1577.
XIE Z W,CHEN Y D,WU W H,et al. Frequency coupling admittance modeling of quasi-PR controlled inverter and its stability comparative analysis under the weak grid [J ] . IEEE Access,2021,9:94912-94922.
RYGG A,MOLINAS M,ZHANG C,et al. A modified sequence-domain impedance definition and its equivalence to the dq-domain impedance definition for the stability analysis of AC power electronic systems [J ] . IEEE Journal of Emerging and Selected Topics in Power Electronics,2016,4(4):1383-1396.
CAO Y F,ZHAO Q S,YE Y Q,et al. ADRC-based current control for grid-tied inverters:design,analysis,and verification [J ] . IEEE Transactions on Industrial Electronics,2020,67(10):8428-8437.
HAMMAD L,AHMED E,TAMOU N. Coordinated control by ADRC strategy for a wind farm based on SCIG considering low voltage ride-through capability [J ] . Protecti on and Control of Modern Power Systems,2022,7(1):82-99.
HUANG L B,WANG D,WANG X F,et al. Gain and phase:decentralized stability conditions for power electronics-dominated power systems [J ] . IEEE Transactions on Power Systems,2024,39(6):7240-7256.
ZHAO D,CHEN W,QIU L. When small gain meets small phase [J ] . arXiv preprint arXiv:2201. 06041,2022.