scholarly journals Distributed Adaptive Virtual Impedance for Reactive Power Sharing in Microgrid

2020 ◽  
pp. 135-140
Author(s):  
Harini M and Dr.S.Chitra
Keyword(s):  
Power Quality ◽  
Reactive Power ◽  
Control Method ◽  
Impedance Control ◽  
Renewable Energy Sources ◽  
Power Sharing ◽  
System Stability ◽  
Environment Simulation ◽  
Control Stability ◽  
Virtual Impedance

The concept of microgrid has been developed to realize flexible coordination control among Distributed Generation (DG) units, improve the power quality supplied to customers. The problem such as the power quality and the system stability due to the intermittency of the renewable energy sources and the fluctuating load profile. The reactive power sharing done by droop control method but reactive power is not accurately shared if there is a local load at each DG. In this paper adaptive virtual impedance control is used to improve the power control stability and sharing performance of real and reactive power sharing is compared by using MATLAB/Simulink environment. Simulation results shows the effectiveness of the proposed method is achieving load reactive power sharing and the voltage restoration is settles in less time.

scholarly journals Modeling of Multiple Master–Slave Control under Island Microgrid and Stability Analysis Based on Control Parameter Configuration

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2223 ◽  
Author(s):  
Haifeng Liang ◽  
Yue Dong ◽  
Yuxi Huang ◽  
Can Zheng ◽  
Peng Li
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Mutual Influence ◽  
Renewable Energy Sources ◽  
System Stability ◽  
Voltage Source ◽  
Stable Operation ◽  
Parameter Configuration ◽  
Islanded Mode ◽  
Virtual Impedance

The stable operation of a microgrid is crucial to the integration of renewable energy sources. However, with the expansion of scale in electronic devices applied in the microgrid, the interaction between voltage source converters poses a great threat to system stability. In this paper, the model of a three-source microgrid with a multi master–slave control method in islanded mode is built first of all. Two sources out of three use droop control as the main control source, and another is a subordinate one with constant power control which is also known as real and reactive power (PQ) control. Then, the small signal decoupling control model and its stability discriminant equation are established combined with “virtual impedance”. To delve deeper into the interaction between converters, mutual influence of paralleled converters of two main control micro sources and their effect on system stability is explored from the perspective of control parameters. Finally, simulation and analysis are launched and the study serves as a reference for parameter setting of converters in a microgrid.

scholarly journals Consensus Control for Reactive Power Sharing Using an Adaptive Virtual Impedance Approach

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2026 ◽  
Author(s):  
Ahmed S. Alsafran ◽  
Malcolm W. Daniels
Keyword(s):  
Rate Of Convergence ◽  
Reactive Power ◽  
Impedance Control ◽  
Power Sharing ◽  
Control Methods ◽  
Triangle Mesh ◽  
Secondary Control ◽  
Consensus Control ◽  
Communication Topology ◽  
Virtual Impedance

Reactive power sharing among distributed generators (DGs) in islanded microgrids (MGs) presents control challenges, particularly in the mismatched feeder line condition. Improved droop control methods independently struggle to resolve this issue and centralized secondary control methods exhibit a high risk of collapse for the entire MG system under any failure in the central control. Distributed secondary control methods have been recently proposed to mitigate the reactive power error evident in the presence of mismatched feeder lines. This paper details a mathematical model of an adaptive virtual impedance control that is based on both leaderless and leader-followers consensus controls with a novel triangle mesh communication topology to ensure accurate active and reactive power sharing. The approach balances an enhanced rate of convergence with the anticipated implementation cost. A MATLAB/Simulink model with six DG units validates the proposed control performance under three different communication structures: namely, ring, complete, and triangle mesh topologies. The results suggest that leaderless consensus control is a reliable option with large DG systems, while the leader-followers consensus control is suitable for the small systems. The triangle mesh communication topology provides a compromise approach balancing the rate of convergence and the expected cost. The extensibility and scalability are advantages of this topology over the alternate ring and complete topologies.

scholarly journals Fuzzy-Based Distributed Cooperative Secondary Control with Stability Analysis for Microgrids

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 399
Author(s):  
Mahmuda Begum ◽  
Mohsen Eskandari ◽  
Mohammad Abuhilaleh ◽  
Li Li ◽  
Jianguo Zhu
Keyword(s):  
Control System ◽  
Stability Analysis ◽  
Cooperative Control ◽  
Dynamic Behaviour ◽  
Reactive Power ◽  
Control Method ◽  
Power Sharing ◽  
System Stability ◽  
Control Technique ◽  
Secondary Control

This research suggests a novel distributed cooperative control methodology for a secondary controller in islanded microgrids (MGs). The proposed control technique not only brings back the frequency/voltage to its reference values, but also maintains precise active and reactive power-sharing among distributed generation (DG) units by means of a sparse communication system. Due to the dynamic behaviour of distributed secondary control (DSC), stability issues are a great concern for a networked MG. To address this issue, the stability analysis is undertaken systematically, utilizing the small-signal state-space linearized model of considering DSC loops and parameters. As the dynamic behaviour of DSC creates new oscillatory modes, an intelligent fuzzy logic-based parameter-tuner is proposed for enhancing the system stability. Accurate tuning of the DSC parameters can develop the functioning of the control system, which increases MG stability to a greater extent. Moreover, the performance of the offered control method is proved by conducting a widespread simulation considering several case scenarios in MATLAB/Simscape platform. The proposed control method addresses the dynamic nature of the MG by supporting the plug-and-play functionality, and working even in fault conditions. Finally, the convergence and comparison study of the offered control system is shown.

scholarly journals A Centralized Shifted Voltage Control Method for Accurate Power Sharing in DC Islanded Microgrids

2021 ◽  
Vol 19 ◽  
pp. 155-159
Author(s):  
Minh-Duc Pham ◽  
◽  
Hong-Hee Lee
Keyword(s):  
Output Voltage ◽  
Control Method ◽  
Voltage Drop ◽  
Renewable Energy Sources ◽  
Control Variable ◽  
Voltage Control ◽  
Power Sharing ◽  
System Stability ◽  
Small Scale ◽  
Dc Microgrid

Due to line impedance mismatch among renewable energy sources (RESs), it is hard to realize accurate power sharing in the DC microgrid system. To solve this issue, a distributed power sharing strategy for adjusting the RES output voltage is developed by adding shifted output voltage into each local controller. Thanks to the shifted voltage, the influence of voltage drop caused by the droop controller is effectively mitigated, so that the DC bus voltage is constantly balanced regardless of the load changes. The proposed method is realized with a centralized approach, and all the required control variable to determine the reference voltage is transmitted through low-bandwidth communication. The controller design and system stability are analyzed in detail with a simplified microgrid model. Small-scale DC microgrid is simulated to verify the effectiveness of the centralized shifted voltage control method.

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