An Islanding Microgrid Power Sharing Approach Using Enhanced Virtual Impedance Control Scheme

2013 ◽  
Vol 28 (11) ◽  
pp. 5272-5282 ◽  
Author(s):  
Jinwei He ◽  
Yun Wei Li ◽  
Josep M. Guerrero ◽  
Frede Blaabjerg ◽  
Juan C. Vasquez
Keyword(s):  
Impedance Control ◽  
Power Sharing ◽  
Control Scheme ◽  
Virtual Impedance

scholarly journals Distributed Finite-Time Secondary Frequency and Voltage Restoration Control Scheme of an Islanded AC Microgrid

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6266
Author(s):  
Junjie Ma ◽  
Xudong Wang ◽  
Siyan Zhang ◽  
Hanying Gao
Keyword(s):  
Power Distribution ◽  
Finite Time ◽  
Voltage Drop ◽  
Impedance Control ◽  
Reference Value ◽  
Voltage Regulation ◽  
Active Power ◽  
Power Sharing ◽  
Control Scheme ◽  
Voltage Deviation

To solve the problems of frequency and voltage deviation caused by the droop control while meeting the requirements of rapid response, a distributed finite-time secondary control scheme is presented. Unlike the traditional cooperative controllers, this scheme is fully distributed; each unit only needs to communicate with its immediate neighbors. A control protocol for frequency restoration and active power sharing is proposed to synchronize the frequency of each unit to the reference value, and achieve accurate active power distribution in a finite-time manner as well. The mismatch of the line impedance is considered, and a consensus-based adaptive virtual impedance control is proposed. The associated voltage drop is considered to be the compensator for the voltage regulation. Then, a distributed finite-time protocol for voltage restoration is designed. The finite-time convergence property and the upper bound of convergence times are guaranteed with rigorous Lyapunov proofs. Case studies in MATLAB are carried out, and the results demonstrate the effectiveness, the robustness to load changes, plug-and play capacity, and better convergence performance of the proposed control scheme.

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 The new power sharing method for threephase parallel inverters with nonlinear loads

2015 ◽  
Vol 18 (1) ◽  
pp. 16-28
Author(s):  
Phuong Minh Le ◽  
Dai Tan Le ◽  
Hoa Thi Xuan Pham
Keyword(s):  
Reactive Power ◽  
Energy System ◽  
Active Power ◽  
Power Sharing ◽  
Control Loop ◽  
Output Impedance ◽  
Nonlinear Loads ◽  
Control Scheme ◽  
Virtual Impedance

This paper presents a new method for controling parallel inverters to share active power and reactive power in the energy system with non-linear loads. In these systems, the virtual output impedance is usually added to the control loop of each inverter to improve the active power and reactive power sharing as well as the quality of the voltage system. Paper also proposes a kind of virtual impedance as a second-order general-integrator (SOGI) scheme. The simulation results in Matlab Simulink show the ability of the proposed controller to good share power P-Q, when connected with unbalanced and nonlinear loads. By using the proposed algorithm allows to reduce the voltage THD to 1.9% and 1.2% for unbalanced and nonlinear loads according by comparision with traditional control scheme.

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