The Impact of Terminal-Voltage Control on the Equilibrium Points and Small-Signal Stability of GFL-VSC Systems

Weak grid stability is crucial for grid-following voltage source converter (GFL-VSC) systems. Current studies primarily focus on the interaction analyses between active-power loops, whereas the influence of reactive-power loops remains unclear. To address this problem, this study focuses on terminal...

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Main Authors: Shun Li, Xing Yao, Cong Fu, Meng Zhan, Bo Bao
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/12/3023
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author Shun Li
Xing Yao
Cong Fu
Meng Zhan
Bo Bao
author_facet Shun Li
Xing Yao
Cong Fu
Meng Zhan
Bo Bao
author_sort Shun Li
collection DOAJ
description Weak grid stability is crucial for grid-following voltage source converter (GFL-VSC) systems. Current studies primarily focus on the interaction analyses between active-power loops, whereas the influence of reactive-power loops remains unclear. To address this problem, this study focuses on terminal-voltage control (TVC) and analyzes its impact on equilibrium points (EPs) and small-signal stability by varying the TVC response speed, including three different cases: considering TVC dynamics, considering TVC rapid responses, and considering TVC slow responses. Firstly, the models of the GFL-VSC system under different scenarios are established and compared. In the EP analysis, for both TVC dynamics and TVC rapid responses, the EP of an active current remains constant and it becomes unstable in a weak grid, whereas for TVC slow responses, the EP undergoes trans-critical bifurcation; specifically, the other EP becomes stable after this bifurcation. Further, in the small-signal stability analysis, three equivalent Heffron–Phillips models based on the phase-locked loop synchronization dynamics with additional synchronization and damping coefficients are constructed and studied. By these systematical studies, the impacts of different TVC response speeds are clarified and summarized, and these analytical results are well supported by MATLAB/Simulink simulations and hardware-in-the-loop experiments.
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spelling doaj-art-c1cef17c15b4497ca8c4dd0260490b7f2025-08-20T03:27:14ZengMDPI AGEnergies1996-10732025-06-011812302310.3390/en18123023The Impact of Terminal-Voltage Control on the Equilibrium Points and Small-Signal Stability of GFL-VSC SystemsShun Li0Xing Yao1Cong Fu2Meng Zhan3Bo Bao4Power Dispatching Control Center of Guangdong Power Grid Co., Ltd., Guangzhou 510000, ChinaSchool of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, ChinaPower Dispatching Control Center of Guangdong Power Grid Co., Ltd., Guangzhou 510000, ChinaSchool of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, ChinaPower Dispatching Control Center of Guangdong Power Grid Co., Ltd., Guangzhou 510000, ChinaWeak grid stability is crucial for grid-following voltage source converter (GFL-VSC) systems. Current studies primarily focus on the interaction analyses between active-power loops, whereas the influence of reactive-power loops remains unclear. To address this problem, this study focuses on terminal-voltage control (TVC) and analyzes its impact on equilibrium points (EPs) and small-signal stability by varying the TVC response speed, including three different cases: considering TVC dynamics, considering TVC rapid responses, and considering TVC slow responses. Firstly, the models of the GFL-VSC system under different scenarios are established and compared. In the EP analysis, for both TVC dynamics and TVC rapid responses, the EP of an active current remains constant and it becomes unstable in a weak grid, whereas for TVC slow responses, the EP undergoes trans-critical bifurcation; specifically, the other EP becomes stable after this bifurcation. Further, in the small-signal stability analysis, three equivalent Heffron–Phillips models based on the phase-locked loop synchronization dynamics with additional synchronization and damping coefficients are constructed and studied. By these systematical studies, the impacts of different TVC response speeds are clarified and summarized, and these analytical results are well supported by MATLAB/Simulink simulations and hardware-in-the-loop experiments.https://www.mdpi.com/1996-1073/18/12/3023renewable energy integrationgrid-following converterterminal-voltage controlsmall-signal stabilityresponse speedcomplex torque method
spellingShingle Shun Li
Xing Yao
Cong Fu
Meng Zhan
Bo Bao
The Impact of Terminal-Voltage Control on the Equilibrium Points and Small-Signal Stability of GFL-VSC Systems
Energies
renewable energy integration
grid-following converter
terminal-voltage control
small-signal stability
response speed
complex torque method
title The Impact of Terminal-Voltage Control on the Equilibrium Points and Small-Signal Stability of GFL-VSC Systems
title_full The Impact of Terminal-Voltage Control on the Equilibrium Points and Small-Signal Stability of GFL-VSC Systems
title_fullStr The Impact of Terminal-Voltage Control on the Equilibrium Points and Small-Signal Stability of GFL-VSC Systems
title_full_unstemmed The Impact of Terminal-Voltage Control on the Equilibrium Points and Small-Signal Stability of GFL-VSC Systems
title_short The Impact of Terminal-Voltage Control on the Equilibrium Points and Small-Signal Stability of GFL-VSC Systems
title_sort impact of terminal voltage control on the equilibrium points and small signal stability of gfl vsc systems
topic renewable energy integration
grid-following converter
terminal-voltage control
small-signal stability
response speed
complex torque method
url https://www.mdpi.com/1996-1073/18/12/3023
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