Journal ArticleDOI
An Improved Design of Current Controller for LCL -Type Grid-Connected Converter to Reduce Negative Effect of PLL in Weak Grid
TLDR
An improved design of current controller, i.e., proportional–integral controller and capacitor-current-feedback active damping, is proposed to reduce the negative effect of PLL on current control and has a strong robustness against wide-range variation of grid impedance.Abstract:
For three-phase LCL -type grid-connected converter, when it is attached to weak grid, current control interacts with phase-locked loop (PLL) via point of common coupling voltage. Consequently, PLL dynamic might deteriorate grid current control and even result in system instability. However, the conventional design method of current controller neglects the impact of PLL, and therefore, it is hard for the current controller to mitigate the negative effect of PLL. In this paper, an improved design of current controller, i.e., proportional–integral controller and capacitor-current-feedback active damping, is proposed to reduce the negative effect of PLL on current control. First, a small-signal impedance model is developed to analyze the impact of PLL on current control. Then, the effect of current controller parameters on the converter output impedance is analyzed, and a design guideline to improve the current controller parameters is presented. With the improved parameters, in precondition of satisfying system stability margin under both stiff and weak grid, the negative effect of PLL on current control can be effectively mitigated without employing additional control strategies. Furthermore, the current control has a strong robustness against wide-range variation of grid impedance. Finally, the experiment demonstrates the effectiveness of the proposed design method.read more
Citations
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Journal ArticleDOI
Impedance Modeling and Stability Analysis of Grid-Connected DFIG-Based Wind Farm With a VSC-HVDC
TL;DR: The theoretical analysis results show that DFIGs behave as an inductance in series with a negative resistance at the resonance point, whose interaction with wind farm side VSC (WFVSC) constitutes an equivalent RLC resonance circuit with negative resistance, and the oscillation tends to occur due to the negative damping.
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
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Book
Fundamentals of Power Electronics
TL;DR: Converters in Equilibrium, Steady-State Equivalent Circuit Modeling, Losses, and Efficiency, and Power and Harmonics in Nonsinusoidal Systems.
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
Impedance-Based Stability Criterion for Grid-Connected Inverters
TL;DR: In this paper, a new method to determine inverter-grid system stability using only the inverter output impedance and the grid impedance is developed, which can be applied to all current-source systems.
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.