Analysis of overall system stability of grid-connected PV inverter with LCL-filter considering two kinds of possible current feedback

2019 ◽  
Vol 60 (2) ◽  
pp. 155-172
Author(s):  
Lisi Tian ◽  
Xiaoguang Cao ◽  
Lankun Lv ◽  
Haokun Wang ◽  
Qiang Yu
Keyword(s):  
System Stability ◽  
Current Feedback ◽  
Lcl Filter ◽  
Pv Inverter

scholarly journals A novel current controller design for grid-integrated PV inverter system

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Ayaz Ahmad ◽  
L. Rajaji ◽  
A. Iqbal
Keyword(s):  
Controller Design ◽  
Vital Role ◽  
Current Feedback ◽  
Lcl Filter ◽  
Design Algorithm ◽  
Grid Voltage ◽  
Pv Inverter ◽  
Current Controller ◽  
Experimental Implementation ◽  
Grid Connected Inverter

AbstractDistributed generators are playing a vital role in supporting the grid in ever-increasing energy demands. Grid code regulation must be followed when integrating the photovoltaic inverter system to the grid. The paper investigates and analyzes a controller model for grid-connected PV inverters to inject sinusoidal current to the grid with minimum distortion. To achieve better tracking and disturbance rejection, a DSP-based current controller is designed with LCL filter. The controller gets the current feedback from the grid, compares it with reference current, and calculates duty cycle to generate PWM pulses to trigger H-bridge converters. The grid voltage is loaded to the initial value in proposed PR controller to ensure the initial inverter voltage to match the grid voltage. The paper presents a novel current controller algorithm for grid-connected inverter system, and simulation is done. A detailed analysis has been carried out to validate the proposed design algorithm. Experimental implementation of the current controller in the DC/AC converter circuits with an LCL filter is done for 5.4 kW to validate and match the simulation model.

scholarly journals Research on Adaptive Suppression of LCL Converter Resonance Grid-Connected System

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Junwei Li ◽  
Yafang Tang ◽  
Junke Li
Keyword(s):  
Particle Swarm Optimization ◽  
Particle Swarm ◽  
Stability Margin ◽  
System Stability ◽  
Current Feedback ◽  
Swarm Optimization ◽  
Lcl Filter ◽  
Rbf Network ◽  
Grid Impedance ◽  
Suppression Method

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.

scholarly journals Potency of PR controller for multiple harmonic compensation for a single-phase grid connected system

2020 ◽  
Vol 11 (3) ◽  
pp. 1491
Author(s):  
D Sattianadan ◽  
Soumen Gorai ◽  
G. R. Prudhvi Kumar ◽  
S. Vidyasagar ◽  
V. Shanmugasundaram
Keyword(s):  
Single Phase ◽  
Harmonic Distortion ◽  
System Stability ◽  
Phase System ◽  
Pv System ◽  
Lcl Filter ◽  
Grid Synchronization ◽  
Harmonic Content ◽  
Wide Range ◽  
Pr Controller

<p><span lang="EN-US">Harmonics and grid synchronization are one of the major problems faced when dealing with a single-phase system. The development of technology in the PV system makes the consumer to use it in a wide range. The power transferred from PV to grid needs DC to AC conversion process which is done by static devices operating with the higher frequencies that causes the harmonics in the grid connected system. The main aim of the paper is to implement grid synchronization and reduce total harmonic distortion in a single-phase grid connected system. The design of LCL filter is addressed in this paper which depends on current ripple, filter size and switching ripple attenuation.  In order to account the harmonic content, the FFT analysis is made both in analysis and Matlab Simulink. The Proportional Resonant (PR) controller is developed and work along with LCL filter for reducing the harmonic content. The stability of the system with PR is analyzed using root locus and bode plots and results are compared with PI controls. The result shows that PR controller performs better compared to the PI controller for reducing the harmonic content present in the single-phase system and for improving the system stability.</span></p>

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