Journal ArticleDOI
An Improved Feedforward Control Method Considering PLL Dynamics to Improve Weak Grid Stability of Grid-Connected Inverters
TLDR
It can be demonstrated that the proposed method can enhance the stability of grid-connected inverters under weak grid conditions and reduce the impact of PLL perturbations on grid-connecting current and low-order harmonics of the network current can be suppressed effectively.Abstract:
Phase-locked loop (PLL) is commonly used for three-phase grid-connected inverters to obtain the information of grid synchronization, and PLL dynamics are the key factors for stable operation of the inverters. Under weak grid conditions, the coupling between PLL and grid impedance can result in harmonic resonance, or even instability in the system. In this paper, the effect of PLL dynamics and grid impedance on the stability of three-phase grid-connected inverters is studied with the d – q impedance model. Besides, the variable transfer relationship is used to analyze the influence of PLL perturbations on output current under weak grid conditions. To suppress low-order harmonics of the network current caused by PLL perturbations under weak grid conditions, a novel feedforward control method is proposed to compensate PLL perturbations and revise the output impedance, where the operation of the inverter and PLL dynamics have been taken into account in the design process. By analyzing the impedance characteristic of the system, it can be demonstrated that the proposed method can enhance the stability of grid-connected inverters under weak grid conditions and reduce the impact of PLL perturbations on grid-connecting current. The experimental results indicate that the low-order harmonics of the network current can be suppressed effectively, which verifies the analysis.read more
Citations
More filters
Journal ArticleDOI
Grid-Synchronization Stability of Converter-Based Resources - An Overview
TL;DR: This paper presents an overview of the synchronization stability of converter-based resources under a wide range of grid conditions, and the small-signal and transient stability of these two operating modes are discussed.
Journal ArticleDOI
Improved Design of PLL Controller for LCL -Type Grid-Connected Converter in Weak Grid
TL;DR: An improved design of PLL controller parameters is proposed to mitigate the negative effect of P LL on the current control in weak grid, and not only the dynamic and static response performance of Pll independent system can be maintained, but also the negative influence of Poll dynamic on theCurrent control can be effectively reduced inWeak grid.
Journal ArticleDOI
Modeling and Stability Analysis of $LCL$ -Type Grid-Connected Inverters: A Comprehensive Overview
Yang Han,Yang Mengling,Hong Li,Ping Yang,Lin Xu,Ernane Antônio Alves Coelho,Josep M. Guerrero +6 more
TL;DR: A comprehensive review on the modeling and stability analysis of the LCL -type grid-connected inverters is conducted, with the emphasis on different modeling methods of inverter output impedance and online impedance measurement techniques.
Journal ArticleDOI
Overview of SOGI-Based Single-Phase Phase-Locked Loops for Grid Synchronization Under Complex Grid Conditions
TL;DR: In this paper, the authors summarized and reviewed the existing achievements of single-phase SOGI-PLL, and pointed out the problems to be solved and the development direction to improve the single phase PLL under more complex and non-ideal grid conditions.
Journal ArticleDOI
Virtual Inductance for Stable Operation of Grid-Interactive Voltage Source Inverters
Aswad Adib,Behrooz Mirafzal +1 more
TL;DR: The effectiveness of the virtual inductance control strategy in weak grids is first proved through closed-loop transfer function analysis and then the system's root locus analysis to determine the stability region of the system versus the grid impedance.
References
More filters
Journal ArticleDOI
Overview of Control and Grid Synchronization for Distributed Power Generation Systems
TL;DR: An overview of the structures for the DPGS based on fuel cell, photovoltaic, and wind turbines is given and the possibility of compensation for low-order harmonics is discussed.
Journal ArticleDOI
Input-Admittance Calculation and Shaping for Controlled Voltage-Source Converters
TL;DR: In this paper, input-admittance expressions for a voltage-source converter are derived and it is seen how the admittance can be shaped in order to get a positive real part in the desired frequency regions by adjusting the controller parameters.
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
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.
Journal ArticleDOI
Modeling and Analysis of Harmonic Stability in an AC Power-Electronics-Based Power System
TL;DR: In this article, an impedance-based analytical approach is employed and expanded to a meshed and balanced three-phase network which is dominated by multiple current and voltage-controlled inverters with LCL-and LC-filters.