scholarly journals Harmonic Suppression Strategy of Photovoltaic Grid Connected Inverter Based on Repetitive and PI Control

2021 ◽  
Vol 2136 (1) ◽  
pp. 012032
Author(s):  
Shengqing Li ◽  
Wang Han ◽  
Xiaobao Li ◽  
Zhijian Wang
Keyword(s):  
Dynamic Performance ◽  
Pi Control ◽  
Harmonic Suppression ◽  
Current Feedback ◽  
Current Harmonics ◽  
Current Controller ◽  
Grid Connected Inverter ◽  
The Mathematical Model ◽  
Suppression Strategy ◽  
Harmonic Problem

Abstract To address the serious harmonic problem of grid connected current in photovoltaic grid-connected inverter, a harmonic suppression strategy based on Repetitive and PI control is proposed in this thesis. According to this strategy, the mathematical model of LCL photovoltaic grid-connected inverter is established with the harmonic mechanism analyzed, the repetitive and PI control is added into the current controller, and the capacitive-current feedback is added to enhance the system damping. Furthermore, it puts PI control on the inner loop and the repetitive control on the outer loop to improve the dynamic performance and achieve the harmonic suppression of the system. Moreover, the simulation results show that this method improves the dynamic response ability of the system, and effectively suppress the grid-connected current harmonics as THD of grid-connected current is 19.65% lower than that of PI controller.

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.

Harmonic suppression of LCL grid-connected inverter based on PI control

2021 ◽  
Author(s):  
Hao Hou ◽  
Shengguo Zhang ◽  
Jiawei Yang ◽  
Weiwen Hu
Keyword(s):  
Pi Control ◽  
Harmonic Suppression ◽  
Grid Connected Inverter

scholarly journals Grid-Connected Resonance Suppression Of Group-Series Photovoltaic Cluster Inverters Based On Hybrid Damping

2021 ◽  
Vol 2136 (1) ◽  
pp. 012020
Author(s):  
Shengqing Li ◽  
Zhijian Wang
Keyword(s):  
Harmonic Distortion ◽  
Current Loop ◽  
Output Current ◽  
Resonance Mechanism ◽  
Current Feedback ◽  
Parallel Voltage ◽  
The Mathematical Model ◽  
Parallel Current ◽  
Suppression Strategy ◽  
Hybrid Damping

Abstract Grid-connected group-series photovoltaic cluster inverter system will cause resonance, which will adversely affect the system. To suppress grid-connected resonance, the mathematical model, resonance mechanism and resonance characteristics of the cluster inverters are analyzed, and a global resonance suppression strategy based on hybrid damping is proposed. In the current loop of the inverter, capacitive current feedback and parallel voltage proportional feed-forward are introduced as active dampers to reduce the harmonics of the parallel current. On this basis, RLC type second-order resonance suppression circuit is added as passive damping to suppress system resonance, so that the output current of the inverters can meet the grid-connected conditions when the cluster is connected to the grid. The simulation and experimental results show that the total harmonic distortion of the grid-connected current decreases from 10.54% to 1.97% after three series photovoltaic cluster inverters adopt this strategy, which effectively suppresses the grid-connected resonance.

scholarly journals Composite Control Strategy of Output Current of LCL Photovoltaic Grid-Connected Inverter

2021 ◽  
Vol 2136 (1) ◽  
pp. 012015
Author(s):  
Shengqing Li ◽  
Xinluo Li ◽  
Qiang Wu ◽  
Xiafei Long
Keyword(s):  
Control Strategy ◽  
Block Diagram ◽  
Harmonic Distortion ◽  
Harmonic Suppression ◽  
Output Current ◽  
Control Block ◽  
Current Harmonics ◽  
Suppression Effect ◽  
Composite Control ◽  
Grid Connected Inverter

Abstract In order to further optimize the output current harmonic suppression effect of photovoltaic grid-connected inverters, a composite control strategy of LCL type photovoltaic grid-connected inverter output current is proposed. This strategy combines proportional complex integral (PCI) control and repetitive control (RC) in parallel, draws a composite control block diagram, introduces a transfer function, and designs PCI and RC control parameters. Prove that the compound control can reduce current harmonics, achieved the purpose of reducing the steady-state error of the fundamental frequency. And adopts a new PCI composite control strategy, which helps to save the cost of the control system. By building the MATLAB/Simulink simulation platform and establishing the PCI+RC composite control model of LCL photovoltaic grid-connected inverter, the comparison of the simulation results shows that compared with the PI+RC control strategy, the total harmonic distortion rate of the grid-connected current is reduced by 25.77. %, significantly improving the quality of grid-connected current.

Application and Simulation of SVPWM Control Techniques in Three-Phase PV Grid-Connected Inverter

2013 ◽  
Vol 415 ◽  
pp. 81-88
Author(s):  
Yang Xue ◽  
Yuan Li ◽  
Jia Dong Zhang ◽  
Jing Lin ◽  
Jun Tao Yang
Keyword(s):  
Pulse Width Modulation ◽  
Control Method ◽  
Dynamic Performance ◽  
Control Technique ◽  
Pi Control ◽  
Loop Control ◽  
Control Techniques ◽  
Three Phase ◽  
Grid Connected Inverter ◽  
Pv Grid

The space vector pulse width modulation (SVPWM), as a new kind of vector control technique, has the advantages of high voltage utilization, less distorted output, simple control method, etc. In this paper, the control technique is applied to three-phase photovoltaic (PV) grid-connected inverter system. It uses double loop control method combined with PI control technique. The simulation model of PV grid-connected inverter system is established in Matlab/Simulink. The simulation results show that the application of SVPWM technique effectively improves the dynamic performance of PV grid inverter system and the THD of grid-connected current is low.

Study on Single-Phase Grid-Connected Inverter Based on PI Control

2014 ◽  
Vol 721 ◽  
pp. 249-252
Author(s):  
Li Jian Hou ◽  
Chang Qing Zhu ◽  
Yue Fei Zhao ◽  
Xue Fei Yan
Keyword(s):  
Single Phase ◽  
Electrical Energy ◽  
Pi Control ◽  
Control Voltage ◽  
Energy Feedback ◽  
Feed Forward Control ◽  
Static Performance ◽  
Grid Connected Inverter ◽  
Set Up ◽  
The Mathematical Model

One of the most important parts in the energy feedback electronic loads is the grid-connected inverter, and its function is to feed the detected electrical energy back to the grid for saving energy. In this paper, the principe of the grid-connected inverter is elaborated, then the PI control and the LCL filter are selected, the mathematical model was set up and the feed forward control voltage was added that suppressing the influence on the system produced by the grid disturbance. The simulation was conducted with the help of Matlab/Simulink, from the simulation waveforms it can be seen that the system dynamic and static performance was good, meanwhile electrical energy can be fed to the grid in the way of unit power factor, eventually the feasibility and superiority of the designing scheme is confirmed.

scholarly journals An Improved Droop Control Strategy for Grid-connected Inverter Power Stability and Harmonic Suppression Under Grid Fluctuation and Inter-harmonics

2021 ◽  
Author(s):  
Wanwan Xu ◽  
Bin Wang ◽  
Jiang Liu ◽  
Da Li
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Control Strategies ◽  
Stability Control ◽  
Droop Control ◽  
Harmonic Suppression ◽  
Current Feedback ◽  
Pass Filter ◽  
Power Stability ◽  
Grid Connected Inverter

This paper presents an improved droop control strategy for grid-connected inverter power stability and power quality under distorted with consideration of grid fluctuation and inter-harmonics. An instantaneous frequency without PLL and amplitude of capacitor voltage feed-forward control strategy is given to power stability control, meanwhile a grid current feedback control is given by an incomplete derivation with a high-pass filter, so that the harmonics and inter-harmonics current can be suppressed. These approaches can provide both good active and reactive power dynamic response under fluctuation of frequency, and rejection ability against harmonic and inter-harmonic voltage. Based on model of inverter, the proposed control strategies are designed in detail. Simulations and experiments are present to validate the effectiveness of proposed method.

scholarly journals A Control Parameters Design Method With Multi-Constrains for an LCL-Filtered Grid-Connected Inverter in a Weak Grid

2022 ◽  
Vol 9 ◽  
Author(s):  
Fuyun Wu ◽  
Zhuang Sun ◽  
Weiji Xu ◽  
Zhizhou Li ◽  
Jianguo Lyu
Keyword(s):  
Steady State ◽  
Design Method ◽  
Dynamic Performance ◽  
Active Damping ◽  
Parameter Design ◽  
Control Parameters ◽  
Weak Grid ◽  
Current Controller ◽  
Grid Impedance ◽  
Grid Connected Inverter

Under weak grid conditions, the variation of the grid impedance will affect the steady-state and dynamic performance of the LCL-filtered grid-connected inverter and even make the inverter unstable. To ensure the system stability and further improve the dynamic performance in a weak grid, a control parameter design method with multi-constrains considering the system bandwidth for the current controller and active damping is proposed in this paper. First, based on the current controller and active damping with only grid current feedback, the effects of control parameters and grid impedance on the LCL resonant suppression and the performance of the inverter are analyzed. Moreover, the parameter constraints of the controllers are derived considering the grid impedance, including stability, resonance suppression, and margin constraints. Furthermore, as the system bandwidth affects the dynamic performance of the inverter, combined with the obtained multi-constraints, the optimal control parameters are determined by achieving the maximum bandwidth of the system against the impedance variation. Compared with other two methods, when the proposed method is applied, the system can operate with a better dynamic and steady-state performance. Finally, experiments are performed on a 2 kW three-phase grid-connected inverter in the weak grid, which verify the effectiveness of the parameter design method proposed in this paper.

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