Journal ArticleDOI
Sequence Impedance Modeling and Stability Comparative Analysis of Voltage-Controlled VSGs and Current-Controlled VSGs
Wu Wenhua,Yandong Chen,Leming Zhou,An Luo,Zhou Xiaoping,Zhixing He,Yang Ling,Xie Zhiwei,Liu Jinming,Mingmin Zhang +9 more
TLDR
The voltage-controlled VSG is more suitable than the current-controlledVSG for grid-connected renewable energy generation in an ultraweak grid from the point of view of system stability and experiment results validate the stability analysis.Abstract:
The premise that the virtual synchronous generator (VSG) can actively support the weak grid is that the VSG can operate stably. In this paper, the small-signal sequence impedance models of the voltage-controlled VSG and the current-controlled VSG are built and the sequence impedance characteristics of these two types of VSGs are compared and analyzed. The sequence impedance of the voltage-controlled VSG, being consistent with the grid impedance characteristics, is generally inductive. By contrast, the sequence impedance of the current-controlled VSG is mainly negative impedance in the middle- and high-frequency area and the impedance amplitude is quite low. Based on the built sequence impedance models and the impedance stability criterion, the influence of the weakness of the grid on the stability of these two types of VSG grid-connected system is analyzed. The results of stability analysis show that the current-controlled VSG is prone to instability while the voltage-controlled VSG remains stable. Therefore, the voltage-controlled VSG is more suitable than the current-controlled VSG for grid-connected renewable energy generation in an ultraweak grid from the point of view of system stability. Finally, experiment results validate the stability analysis.read more
Citations
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Journal ArticleDOI
A comprehensive review of virtual synchronous generator
TL;DR: An overview of different topologies to virtual inertia is presented along with a detailed description of the VSG structure, and VSG control defining active and reactive power control, and voltage and frequency control is explained in detail.
Journal ArticleDOI
Line Impedance Cooperative Stability Region Identification Method for Grid-Tied Inverters Under Weak Grids
TL;DR: The proposed line impedance cooperative stability region identification method is more effective and less conservative than the norm-based stability criteria and can provide guidance for system planning and stabilization method researches with simplified computational process.
Journal ArticleDOI
SoC-Based Droop Coefficients Stability Region Analysis of the Battery for Stand-Alone Supply Systems With Constant Power Loads
TL;DR: In this article, a droop coefficients stability region analysis approach was proposed to assess the droop coefficient stability point, but not the stability region, in which a novel forbidden region criterion based on the return-ratio matrix was constructed, which reduced conservatism compared with normbased impedance criteria and partial forbidden region criteria.
Journal ArticleDOI
Active Power Oscillation and Suppression Techniques Between Two Parallel Synchronverters During Load Fluctuations
TL;DR: In this article, a new control strategy for suppressing power oscillation especially the oscillation excitation is proposed, which effectively suppresses the power oscillations by adding a virtual damping element for enhancing the system damping and a virtual reactance for reducing the amplitude excitation to the conventional control scheme.
Journal ArticleDOI
The Dual Control With Consideration of Security Operation and Economic Efficiency for Energy Hub
TL;DR: The decentralized control of energy hubs can be realized to eliminate the impact of communication on security operation by implementing the proposed method based on the improved equal incremental consumption principle.
References
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Journal ArticleDOI
Synchronverters: Inverters That Mimic Synchronous Generators
Qing-Chang Zhong,George Weiss +1 more
TL;DR: The idea of operating an inverter to mimic a synchronous generator (SG) is motivated and developed, and the inverters that are operated in this way are called synchronverters.
Journal ArticleDOI
Impedance-Based Stability Criterion for Grid-Connected Inverters
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Journal ArticleDOI
Analysis of D-Q Small-Signal Impedance of Grid-Tied Inverters
TL;DR: In this article, the small-signal impedance of three-phase grid-tied inverters with feedback control and phase-locked loop (PLL) in the synchronous reference ( d-q ) frame is analyzed.
Journal ArticleDOI
Self-Synchronized Synchronverters: Inverters Without a Dedicated Synchronization Unit
TL;DR: In this paper, a self-synchronized synchronverter is proposed to improve the performance of grid-connected inverters by removing the dedicated synchronization unit, which can automatically synchronize itself with the grid before connection and track the grid frequency after connection.
Journal ArticleDOI
Impedance Modeling and Analysis of Grid-Connected Voltage-Source Converters
Mauricio Cespedes,Jian Sun +1 more
TL;DR: In this paper, a small-signal impedance modeling of grid-connected three-phase converters for wind and solar system stability analysis is presented, where a converter is modeled by a positive-sequence and a negative-sequence impedance directly in the phase domain.