Adaptive Virtual Impedance-Based Reactive Power Sharing in Virtual Synchronous Generator Controlled Microgrids

2021 ◽  
Vol 57 (1) ◽  
pp. 46-60
Author(s):  
Xiaodong Liang ◽  
Chowdhury Andalib-Bin-Karim ◽  
Weixing Li ◽  
Massimo Mitolo ◽  
Md Nasmus Sakib Khan Shabbir
Keyword(s):  
Reactive Power ◽  
Synchronous Generator ◽  
Power Sharing ◽  
Virtual Impedance ◽  
Virtual Synchronous Generator

scholarly journals Presynchronous Grid-Connection Strategy of Virtual Synchronous Generator Based on Virtual Impedance

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Guanfeng Zhang ◽  
Junyou Yang ◽  
Haixin Wang ◽  
Jia Cui
Keyword(s):  
Reactive Power ◽  
Power Grid ◽  
Synchronous Generator ◽  
Synchronization Control ◽  
Distributed Power Generation ◽  
Grid Connection ◽  
Power Exchange ◽  
Phase Amplitude ◽  
Virtual Impedance ◽  
Virtual Synchronous Generator

The virtual synchronous generator (VSG) technology of inverter is widely used to provide the inertia and damping support for power system. However, an additional measurement device PLL (phase-locked loop) is required in the virtual synchronous generator grid connection to track the voltage phase, amplitude, and frequency, which restricts the flexible output of the distributed power generation system. To tackle this challenge, a method for grid-connected control of virtual synchronous generator based on virtual impedance is proposed. It is assumed that there is a virtual power exchange between the synchronous machine and the power grid when the virtual synchronous generator is off-grid, the virtual impedance is developed to calculate the virtual current, and when the virtual current is zero, the output voltage of the VSG can be synchronized with the voltage of the power grid, thereby seamlessly switching between off-grid and grid-connected VSG. A semiphysical simulation platform is built based on RT-LAB; simulation and experimental results show that the proposed grid synchronization control strategy of the VSG can achieve seamless transform between different VSG modes, which is simpler than the conventional synchronization control, while having a good active and reactive power tracing performance.

A Power Sharing Method for Parallel Inverters with Virtual Synchronous Generator Control Strategy

2016 ◽  
Vol 4 (2) ◽  
pp. 317
Author(s):  
Sara Yahia Altahir Mohamed ◽  
Xiangwu Yan
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Voltage Drop ◽  
Synchronous Generator ◽  
Power Sharing ◽  
System Stability ◽  
Droop Control ◽  
Active And Reactive Power ◽  
Virtual Inertia ◽  
Virtual Synchronous Generator

<p>A new power sharing method of a virtual sychronous generator control based inverters is introduced in this paper. Since virtual synchronous generator has virtual inertia and damping properties, it significantly enhances the grid stability. However, its output power considerably affects by the line impedance. Thus, in this paper, the relation between the droop control and the line impedance is analyzed at first. Then, by appling an improved droop control strategy to an inverter based on the virtual sychronous generator control, achieving proportional active and reactive power sharing unaffected by the line impedance is realized. The result shows that a smooth response is achieved. As well as, the voltage drop caused by the line impedance is totally compensated. As a result, the system stability is furtherly improved. At last, the effectiveness of the proposed method is verified through MATLAB/Simulink.</p>

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.

scholarly journals Virtual Synchronous Generator Grid Connected Control Method Based on Virtual Impedance

2019 ◽  
Vol 1187 (2) ◽  
pp. 022026
Author(s):  
Bao-zhu Shao ◽  
Guan-feng Zhang ◽  
Jun-you Yang ◽  
Fei-fei Gao ◽  
Feng Sun ◽  
...  
Keyword(s):  
Control Method ◽  
Synchronous Generator ◽  
Virtual Impedance ◽  
Virtual Synchronous Generator
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