Adaptive Virtual Impedance Control Method for Accurate Reactive Power Sharing and Circulating Current Suppression in Islanded Microgrid

2019 ◽  
Author(s):  
Minh Duc Pham ◽  
Hong Hee Lee
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Impedance Control ◽  
Power Sharing ◽  
Circulating Current ◽  
Islanded Microgrid ◽  
Virtual Impedance

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 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 Decentralized Virtual Impedance-based Circulating Current Suppression Control for Islanded Microgrids

2021 ◽  
Vol 11 (1) ◽  
pp. 6734-6739
Author(s):  
A. Abu Bakar ◽  
E. Pathan ◽  
M. K. Khan ◽  
M. A. Sadiq ◽  
M. I. Rabani ◽  
...  
Keyword(s):  
Power Distribution ◽  
Voltage Drop ◽  
Impedance Control ◽  
Negative Resistance ◽  
Power Sharing ◽  
Control Technique ◽  
Droop Control ◽  
Output Impedance ◽  
Circulating Current ◽  
Virtual Impedance

Parallel connected inverters in islanded mode, are getting momentous attention due to their ability to increase the power distribution and reliability of a power system. When there are different ratings of Distributed Generation (DG) units, they will operate in parallel connection due to different output voltages, impedance mismatch, or different phase that can cause current to flow between DG units. The magnitude of this circulating current sometimes can be very large and damage the DG inverters and also cause power losses that affect power-sharing accuracy, power quality, and the efficiency of the Microgrid (MG) system. Droop control, improved droop control, and virtual impedance control techniques and modifications in the virtual impedance control technique are widely used to suppress the circulating current. However, the addition of the virtual impedance to each inverter to compensate the output impedance is resistive or inductive in nature. The resistive nature of the output impedance always causes a certain voltage drop, whereas the inductive nature of the output impedance causes phase delay for the output voltage. Both problems are addressed by the proposed control mechanism in this paper. Negative resistance, along with virtual impedance, is utilized in the proposed control strategy. The output impedance is to be maintained as inductive in nature to achieve good load sharing in droop control MGs. The simulation results validate the proposed control scheme.

scholarly journals Virtual Impedance-based Decentralized Power Sharing Control of an Islanded AC Microgrid

2021 ◽  
Vol 11 (1) ◽  
pp. 6620-6625 ◽  
Author(s):  
E. Pathan ◽  
M. H. Khan ◽  
H. Arshad ◽  
M. K. Aslam ◽  
D. Jahangir ◽  
...  
Keyword(s):  
Power Systems ◽  
Decentralized Control ◽  
Control Strategy ◽  
Impedance Control ◽  
Power Sharing ◽  
Voltage Source ◽  
Renewable Energy Resources ◽  
Circulating Current ◽  
Distribution Generation ◽  
Virtual Impedance

The future of power systems depends on the microgrid (MG) which includes distribution generators utilizing Renewable Energy Resources (RERs) and storage facilities. Decentralized control techniques are more reliable and stable in comparison with centralized controlled techniques. In this paper, a decentralized control strategy is presented for an islanded AC MG system. The control strategy includes improved droop control and virtual impedance. Control strategy with PI controllers to control the voltage and current is implemented to two Voltage Source Inverter (VSI) distribution generation units connected in parallel through a Point of Common Coupling (PCC). Circulating current and power-sharing deviations caused by the mismatched line impedance were taken into account. The proposed control scheme was tested in MATLAB/Simulink. Power-sharing accuracy and circulating current suppression were obtained by implementing the proposed virtual impedance-based decentralized control strategy.

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