Open Access

ARTICLE

Small-Signal Stability Analysis of Solar-Storage Hybrid Heterogeneous Power Generation Systems Based on Graphical Block-Oriented Modeling

Qiang Liu¹, Yongqiang Zhou¹, Chaoyang Lu², Zhen Yan¹, Yanwen Li¹, Gangui Yan², Yupeng Wang^2,*
1 Xingtai Power Supply Branch, State Grid Hebei Electric Power Co., Ltd., Xingtai, 054001, China
2 Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology, Ministry of Education (Northeast Electric Power University), Jilin, 132012, China
* Corresponding Author: Yupeng Wang. Email:
(This article belongs to the Special Issue: New Energy and Energy Storage System)

Energy Engineering https://doi.org/10.32604/ee.2025.074766

Received 17 October 2025; Accepted 16 December 2025; Published online 14 January 2026

Abstract

Hybrid photovoltaic and energy storage systems play a critical role in enhancing grid stability; however, the sub-synchronous oscillation issues induced by their power electronic interfaces cannot be overlooked. This study proposes a graphical block-based modeling method for a hybrid power generation system composed of grid-following (GFL) photovoltaic and grid-forming (GFM) energy storage units. The method abstracts each system component into graphical modules with clearly defined interfaces, enables intuitive construction in the Matlab/Simulink environment, and utilizes built-in functions to automatically generate global system equations. While ensuring model accuracy, it significantly improves modeling intuitiveness, efficiency, and scalability, and avoids algebraic errors that are difficult to eliminate in traditional manual derivations. Based on the constructed model, this paper identifies the dominant sub-synchronous oscillation modes of the system through eigenvalue analysis. Furthermore, using the root locus method, it systematically reveals the dynamic influence of key control parameters of the GFM energy storage unit—such as the active voltage proportional coefficient k_p1,M, the reactive voltage proportional coefficient k_p2,M, the reactive voltage integral coefficient k_i2,M, and the reactive current integral coefficient k_i4,M—on the small-signal stability of the system. The research shows that reasonably increasing these key parameters can effectively enhance the small-signal stability of the photovoltaic-storage hybrid system. Finally, time-domain simulation results verify the correctness of the proposed modeling method and related conclusions, thereby providing a theoretical basis for the stable operation and controller design of hybrid photovoltaic-storage power generation systems.

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Keywords

GFL photovoltaic; GFM energy storage; solar-storage hybrid power generation system; state-space model; graphical block-based modeling; small-signal stability analysis

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