Robustness Investigation of Multi-Inverter-Paralleled Grid-Connected System with LCL-Filter Based on the Grid-Impedance Allocation Mechanism

LCL-type converters are widely used in grid-connected systems due to their small size and good filtering performance. However, the resonance suppression problem brought by the LCL filter cannot be ignored. The capacitive current feedback is a commonly used resonance suppression method. In applications, the grid impedance can cause LCL filter resonance. Thus, this paper presents an adaptive resonance suppression method based on the RBF network optimized by particle swarm optimization. This method optimizes the initial parameters of the RBF network through particle swarm optimization, identifies the parameters of the PI controller by RBF neural network’s own identification capability, and updates the active damping coefficient based on constraints such as stability margin, thereby realizing the LCL-type inverter to maintain the system stability when the grid impedance changes. The effectiveness of the method is verified by experiments.

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Adaptive digital notch filter based on online grid impedance estimation for grid-tied LCL filter systems

Electric Power Systems Research ◽

10.1016/j.epsr.2019.02.023 ◽

2019 ◽

Vol 172 ◽

pp. 183-192 ◽

Cited By ~ 1

Author(s):

Jing Yuan ◽

Ahmed Al Durra ◽

Ehab El-Saadany

Keyword(s):

Notch Filter ◽

Lcl Filter ◽

Grid Impedance ◽

Digital Notch Filter

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Grid Impedance Estimation by Measuring Only the Current Injected to the Grid by a VSI With $LCL$ Filter

IEEE Transactions on Industrial Electronics ◽

10.1109/tie.2020.2973910 ◽

2021 ◽

Vol 68 (3) ◽

pp. 1841-1850 ◽

Cited By ~ 2

Author(s):

Roberto A. Fantino ◽

Claudio A. Busada ◽

Jorge A. Solsona

Keyword(s):

Lcl Filter ◽

Grid Impedance

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Control of Grid Connected Inverter with PR Controller and LCL Filter for Interfacing Renewable Energy Sources

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.984-985.979 ◽

2014 ◽

Vol 984-985 ◽

pp. 979-989

Author(s):

K. Deepthi ◽

A. Vijayakumari ◽

Arun Joshy

Keyword(s):

Renewable Energy ◽

Renewable Energy Sources ◽

Design Procedure ◽

Lcl Filter ◽

Pwm Inverter ◽

Grid Impedance ◽

Pr Controller ◽

Primary Focus ◽

Grid Connected Inverter ◽

Configuration Changes

This paper presents a design procedure for Proportional-Resonant (PR) controller and a third order LCL filter which decide the performance of the converter that is used to interface the renewable energy source to the grid. The primary focus of the paper is to evaluate the performance of the controller with the filter for a microgrid application. A scaled down model of microgrid available in the department laboratory is considered for the performance evaluation of the designed controller. The system is simulated with a 2kVA PWM inverter and tested under conditions such as change in grid impedance, grid frequency and step change in reference current. The simulation results show that the PR controller with LCL filter tracks the reference with zero steady state error and the controller is found to be immune to grid frequency and micro-grid configuration changes.

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