High-Frequency Oscillation Suppression Strategy for Interconnected Grid-Forming Energy Storage and Grid-Following HVDC Systems Based on Impedance Analysis
Year: 2026
Type: article
Abstract: Interconnecting grid-following (GFL) and grid-forming (GFM) converters help stabilize weak grids with a high penetration of power electronics, but dynamic interactions can induce high-frequency oscillations (HFOs). The HFO mechanism within interconnected grid-forming battery energy storage (GFM-BESS) and grid-following VSC-HVDC systems remains unresolved, with viable suppression strategies yet to be established. To address this, this study utilizes harmonic linearization to derive small-signal frequency-domain impedance models for both devices. The models are developed for high-frequency-oscillation analysis: the GFM-BESS model retains all control loops, while the GFL-HVDC model retains the current loop and the phase-locked loop, with the slow outer loop omitted as justified within the high-frequency band. Frequency-coupled 2×2 impedance matrices are established to capture the frequency coupling introduced by the power loops and the phase-locked loop. Stability is established by the argument principle, the exact Nyquist encirclement count and the roots of the closed-loop characteristic function. At a nominal control delay of 50 μs, the voltage-loop proportional gain has two finite stability boundaries: insufficient proportional action fails to damp the integral-loop mode, whereas excessive proportional action destabilizes the delay-affected filter mode. The resulting two-sided admissible interval is 0.0771
Source: Energies
DOI: 10.3390/en19153635
Authors: Jun Deng, Xiaoping Wang, Yichun Wang, Weixiang Wang
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W7172313729