A Method of Harmonic Current Suppression in Photovoltaic Grid-Connected Systems

2013 ◽  
Vol 303-306 ◽  
pp. 1145-1148
Author(s):  
Jia Guo ◽  
Zhi Gang Li ◽  
Ya Ping Cheng ◽  
Kai Huang ◽  
Chun Yan Cui
Keyword(s):  
Control Strategy ◽  
Current Waveform ◽  
Output Current ◽  
Harmonic Current ◽  
Current Harmonics ◽  
Waveform Control ◽  
Photovoltaic Power ◽  
Grid Connected Inverter ◽  
The Stability ◽  
Power Generation Systems

The grid-connected inverter plays an important role in the photovoltaic power generation systems, the output of the grid current harmonics affect the stability of the grid. The reason of grid inverter output current distortion, a detailed analysis of current waveform control strategy and its effectiveness of the grid-connected inverter harmonic current suppression is introduced based on the d-q coordinates in this paper.

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.

A Study of Novel Cuk Grid-Connected Inverter Based on Double-Loop Control

2013 ◽  
Vol 846-847 ◽  
pp. 543-546
Author(s):  
Yue Zhou
Keyword(s):  
Control Strategy ◽  
Topological Structure ◽  
Double Loop ◽  
Output Current ◽  
Loop Control ◽  
Current Harmonics ◽  
New Type ◽  
Parallel Circuit ◽  
Parallel Input ◽  
Grid Connected Inverter

A kind of Cuk grid-connected inverter is proposed for renewable energy power generation. The grid-connected inverter using Cuk input series output parallel circuit, form a new type of non isolated single stage output parallel input series double Cuk inverter circuit. Firstly, On the basis of the topological structure and principle, the double-loop control strategy is researched to enhance its adaptability and robustness. Simulative results show that,the proposed inverter with double-loop control has better dynamic and static performances, with less output current harmonics and better waveform quality.

scholarly journals A Novel Control Strategy for Grid-Connected Inverter Based on Iterative Calculation of Structural Parameters

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3306 ◽  
Author(s):  
Zhenao Sun ◽  
Dazhi Wang ◽  
Tianqing Yuan ◽  
Zairan Liu ◽  
Jiahui Yu
Keyword(s):  
Control Strategy ◽  
Structural Parameters ◽  
Dynamic Performance ◽  
Open Loop ◽  
Output Current ◽  
Open Loop System ◽  
Iterative Calculation ◽  
Static Performance ◽  
Grid Connected Inverter ◽  
Pv Grid

A novel control strategy that is based on iterative calculation of structural parameters is proposed for grid-connected inverter in this paper. The proposed strategy has a good dynamic performance, which makes it particularly suitable for the application of PV grid-connected generation. First, a second-order discretization mathematical model of grid-connected inverter control is established in the dq frame. The corresponding relation between the control signal and the output current is deduced in formulas. Then, the values of structural parameters in the formulas can be obtained through iterative calculation, which can further reduce the amount of calculation. After several iteration cycles, the structural parameters are approximately equal to their actual values and the inverter can be controlled as an open-loop system with its dynamic performance optimized. At last, simulation and experiments are performed. The results show that the static performance of the proposed strategy is as good as that of the classical ones, but its dynamic performance is improved significantly.

Separated-PI Control Strategy and Stability Analysis of a Single-Phase Inverter Connected to the Grid with a LCL Filter

2013 ◽  
Vol 291-294 ◽  
pp. 2464-2469
Author(s):  
Dian Li Hou ◽  
Qing Fan Zhang ◽  
Xiao Liu
Keyword(s):  
Control Strategy ◽  
Single Phase ◽  
Dynamic Performance ◽  
Structural Features ◽  
Lcl Filter ◽  
Phase Inverter ◽  
Hurwitz Stability ◽  
Single Phase Inverter ◽  
Grid Connected Inverter ◽  
The Stability

Because of the powerful filtering ability the third-order LCL filters has been widely used in grid-connected inverters, but there are some problems to be solved on systems stability and control accuracy. A separated-PID control strategy has been proposed according to the PID characteristics and the structural features of a single-phase inverter connected to the grid with a LCL filter. This control strategy has some advantages as a strong dynamic tacking stability, and the system output has a small steady state error. A detailed description is presented on this control strategy applied in the single-phase grid inverter with a LCL filter. According to the Routh-Hurwitz stability criterion, the stability of a grid-connected inverter system based on the proposed control strategy has been analyzed. Finally, waveforms of this inverter have been presented through a simulation to show the steady and dynamic performance of the proposed scheme.

Optimization of Photovoltaic Grid-Connected Inverter System

2013 ◽  
Vol 722 ◽  
pp. 161-165
Author(s):  
Xing Quan Wu ◽  
Qiu Peng Li ◽  
Yan Li
Keyword(s):  
Reactive Power ◽  
Photovoltaic System ◽  
Space Vector ◽  
Current Harmonics ◽  
Grid Connection ◽  
Distributed Parameters ◽  
Grid Connected Inverter ◽  
The Stability ◽  
Photovoltaic Plant ◽  
Rotating Coordinates

In order to increase the stability of grid connection of photovoltaic plant, effort has been made to study the grid connection principle of photovoltaic plant, mathematical model of grid-connected photovoltaic inverter and power grid distributed parameters, and improve traditional space vector control theory to keep d axis of d-q rotating coordinates consistent with the rotating space vector of network voltage and realize decoupling control over active power and reactive power of grid-connected photovoltaic system, through real-time detection of fluctuations in grid-connected current and network voltage, get voltage current dual-loop to place feedback control, which effectively compensates the modulating signal of inverter, reduces photovoltaic grid-connected output voltage and current harmonics so that the system has better robustness, and improves the reliability of grid connection.

scholarly journals Weighted average current method for active damping control based on grid voltage feed-forward

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Shengqing Li ◽  
Xinluo Li ◽  
Xiaobao Lee
Keyword(s):  
Control Strategy ◽  
Weighted Average ◽  
Stability Margin ◽  
Current Control ◽  
Power Network ◽  
Weak Current ◽  
Damping Control ◽  
Average Current ◽  
Grid Connected Inverter ◽  
The Stability

AbstractIn the weak current network environment, the existence of power network impedance will reduce the current control stability margin of LCL grid connected inverter, the stability margin will gradually deteriorate as the inductive component of the power network impedance increases, leading to system instability. In this paper, an improved weighted average current control strategy is proposed, which is based on the active damping control of the voltage feedforward of the charged network. In the new control strategy, with the zero-pole cancellation method, a new weighting coefficient related only to the parameters of LCL filter is obtained, which reduces the order of the system, suppresses the influence of power network impedance, and improves the stabilization of the system, getting better inverter output current quality. Then the influence of power network impedance on the control system of grid connected inverter is analyzed, and the feed-forward control of grid voltage is improved to improve the stability of inverter in weak current network. The Bode diagram analysis and MATLAB simulation results proved that the proposed control strategy is feasible.

The Application of Sliding Mode Control in Current Source Converter

2014 ◽  
Vol 945-949 ◽  
pp. 2331-2337
Author(s):  
Jing Bai ◽  
Shi Qi Lu ◽  
Jian Liu
Keyword(s):  
Control Strategy ◽  
Sliding Mode ◽  
Current Source ◽  
Variable Structure ◽  
Current Waveform ◽  
Output Current ◽  
Fast Tracking ◽  
Control Scheme ◽  
Existence Domain ◽  
Current Source Converter

Current source converter is a variable structure system due to its switching nature, so that it can easily cause the output current waveform distortion and can not be accurately track the reference current. To solve the above problems, this paper proposes a new variable structure control strategy with fan-shaped sliding domain in the current source converter control system. In the control strategy, the paper deduces the switching surface and switching control law of SMVSC, and calculates the sliding existence domain based on the mathematical model of current source converter. Finally, the simulation results show that the control scheme can make current source converter have better output current waveform, fast tracking the reference current, and strong anti-interference ability. Therefore, the control scheme is correct, effective and feasible.

scholarly journals Coordinate Control of Power/Current for Grid-Connected Inverter Based on PCI Controller under Unbalanced Grid Conditions

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Chencong Zhao ◽  
Jun Liu ◽  
Zhouhua Xie ◽  
Feihang Zhou
Keyword(s):  
Output Power ◽  
Control Strategy ◽  
Balance Control ◽  
Weight Coefficient ◽  
Current Harmonics ◽  
Coordinate Control ◽  
Harmonic Components ◽  
Grid Connected Inverter ◽  
Complex Integral ◽  
Unbalanced Grid

The oscillations on output power and distortion of the inverter currents will occur in the case of unbalanced grid voltage faults. Constant output power and good current quality cannot be achieved simultaneously. Aiming at these problems, a coordinate control strategy for suppressing power fluctuations and current harmonics is proposed by analyzing instantaneous power control and current balance control. The proposed control is achieved by adjusting the weight coefficient of current reference values to change the current harmonic contents based on proportional complex integral (PCI) controller and proportional multiple complex integral (PMCI) controller. The control strategy with a simple control structure neither needs to detect harmonic components of the inverter currents, nor needs to separate the positive and negative components of voltage and current, which is easy to be realized. The feasibility and effectiveness of the proposed control are verified by the comparison and analysis of simulation.

Sign in / Sign up

Export Citation Format

Share Document