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 Novel Hierarchical Control Strategy for Low-Voltage Islanded Microgrids Based on the Concept of Cyber Physical System

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1835 ◽  
Author(s):  
Qiuxia Yang ◽  
Dongmei Yuan ◽  
Xiaoqiang Guo ◽  
Bo Zhang ◽  
Cheng Zhi
Keyword(s):  
Control Strategy ◽  
Physical System ◽  
Reactive Power ◽  
Low Voltage ◽  
Hierarchical Control ◽  
Physical Layer ◽  
Cyber Physical System ◽  
Droop Control ◽  
Control Effect ◽  
Consensus Control

Based on the concept of cyber physical system (CPS), a novel hierarchical control strategy for islanded microgrids is proposed in this paper. The control structure consists of physical and cyber layers. It’s used to improve the control effect on the output voltages and frequency by droop control of distributed energy resources (DERs), share the reactive power among DERs more reasonably and solve the problem of circumfluence in microgrids. The specific designs are as follows: to improve the control effect on voltages and frequency of DERs, an event-trigger mechanism is designed in the physical layer. When the trigger conditions in the mechanism aren’t met, only the droop control (i.e., primary control) is used in the controlled system. Otherwise, a virtual leader-following consensus control method is used in the cyber layer to accomplish the secondary control on DERs; to share the reactive power reasonably, a method of double virtual impedance is designed in the physical layer to adjust the output reactive power of DERs; to suppress circumfluence, a method combined with consensus control without leader and sliding mode control (SMC) is used in the cyber layer. Finally, the effectiveness of the proposed hierarchical control strategy is confirmed by simulation results.

Control of inverters in standalone andgrid-connected microgrid using different control strategies

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vikash Gurugubelli ◽  
Arnab Ghosh
Keyword(s):  
Transient Response ◽  
Control Strategy ◽  
Control Strategies ◽  
Power Balance ◽  
Droop Control ◽  
Content Type ◽  
Simulink Simulation ◽  
Time Simulation ◽  
Simulation Results ◽  
First Time

Purpose The share of renewable energy sources (RESs) in the power system is increasing day by day. The RESs are intermittent, therefore maintaining the grid stability and power balance is very difficult. The purpose of this paper is to control the inverters in microgrid using different control strategies to maintain the system stability and power balance. Design/methodology/approach In this paper, different control strategies are implemented to the voltage source converter (VSC) to get the desired performance. The DQ control is a basic control strategy that is inherently present in the droop and virtual synchronous machine (VSM) control strategies. The droop and VSM control strategies are inspired by the conventional synchronous machine (SM). The main objective of this work is to design and implement the three aforementioned control strategies in microgrid. Findings The significant contributions of this work are: the detailed implementation of DQ control, droop control and VSM control strategies for VSC in both grid-connected mode and standalone mode is presented; the MATLAB/Simulink simulation results and comparative studies of the three aforementioned controllers are introduced first time in the proposed work; and the opal-RT digital real-time simulation results of the proposed VSM control show the superiority in transient response compared to the droop control strategy. Research limitations/implications In the power system, the power electronic-based power allowed by VSM is dominated by the conventional power which is generated from the traditional SM, and then the issues related to stability still need advance study. There are some differences between the SM and VSM characteristics, so the integration of VSM with the existing system still needs further study. Economical operation of VSM with hybrid storage is also one of the future scopes of this work. Originality/value The significant contributions of this work are: the detailed implementation of DQ control, droop control and VSM control strategies for VSC in both grid-connected mode and standalone mode is presented; the MATLAB/Simulink simulation results and comparative studies of the three aforementioned controllers are introduced first time in the proposed work; and the opal-RT digital real-time simulation results of the proposed VSM control show the superiority in transient response compared to the droop control strategy.

An Advanced Droop Control Strategy for Reactive Power: Assessment in Islanded Microgrids

2021 ◽  
pp. 1-1
Author(s):  
Manuela Minetti ◽  
Alessandro Rosini ◽  
Gio Battista Denegri ◽  
Andrea Bonfiglio ◽  
Renato Procopio
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Droop Control

scholarly journals An Improved Droop Control Strategy for Reactive Power Sharing in Islanded Microgrid

2015 ◽  
Vol 30 (6) ◽  
pp. 3133-3141 ◽  
Author(s):  
Hua Han ◽  
Yao Liu ◽  
Yao Sun ◽  
Mei Su ◽  
Josep M. Guerrero
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Power Sharing ◽  
Droop Control ◽  
Islanded Microgrid

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 Self-Adjusting Droop Control Strategy to Improve Reactive Power Sharing in Islanded Microgrid

2020 ◽  
Vol 11 (3) ◽  
pp. 1624-1635 ◽  
Author(s):  
Dharmendra Kumar Dheer ◽  
Yusuf Gupta ◽  
Suryanarayana Doolla
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Power Sharing ◽  
Droop Control ◽  
Islanded Microgrid

Reseach on Control Strategy Based on p-q-r Theory for Four-Leg Grid-Connected Inverter

2012 ◽  
Vol 433-440 ◽  
pp. 1099-1105
Author(s):  
Hong Bing Chen ◽  
Xing Zhang
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Experimental Result ◽  
Control Algorithms ◽  
Three Phase ◽  
Result Show ◽  
Grid Connected Inverter ◽  
Full Design ◽  
The Mathematical Model

The mathematical model for three-phase four-leg grid-connected inverter is modeled by the simplified p-q-r theory. The control strategy is proposed based on the characteristic of controlled variables. PI algorithm is adopted for variables of p axis and q axis, and PR algorithm is adopted for variable of r axis. The full design and analysis of the proposed control algorithms are given in this paper. Simulation results and experimental result show that quality of four-leg grid-connected inverter output current is higher, and effectiveness of the proposed control strategies is validated by all results.

Sign in / Sign up

Export Citation Format

Share Document