Stability Analysis on Coordinated Operation of the Hybrid Grid‐Connected Converter Systems

ABSTRACT As hybrid grid‐connected systems comprising Grid‐Following (GFL) and Grid‐Forming (GFM) converters become prevalent, the stability implications of their heterogeneous interactions remain insufficiently understood. To address this challenge, a unified frequency‐domain stability analysis framework for hybrid renewable power plants is proposed. First, a unified sequence impedance model is derived using harmonic linearization, explicitly incorporating the coupling dynamics between the GFL's Phase‐Locked Loop (PLL) and the GFM's Virtual Synchronous Generator (VSG) control. Unlike conventional independent modeling, this framework rigorously quantifies the interaction effects at the Point of Common Coupling (PCC). Subsequently, based on the Generalized Nyquist Criterion, the stability impacts of GFM spatial distribution and penetration ratios are investigated. Quantitative results demonstrate that the GFM‐centralized link injection strategy yields a phase margin approximately four times larger than dispersed configurations (12.15° vs. ~3°). Furthermore, increasing GFM penetration from 0% to 100% is shown to reduce the maximum phase difference by 43.7°, significantly enhancing high‐frequency disturbance rejection. Finally, a global sensitivity and parameter interaction analysis is conducted to formulate practical parameter tuning guidelines, identifying dominant coupling paths to mitigate oscillations. The accuracy of the theoretical models and the effectiveness of the proposed strategies are validated through comprehensive time‐domain simulations.