Distributed control scheme for accurate reactive power sharing with enhanced voltage quality for islanded microgrids

2020 ◽  
Vol 20 (2) ◽  
pp. 601-613 ◽  
Author(s):  
Tuan V. Hoang ◽  
Hong-Hee Lee
Keyword(s):  
Distributed Control ◽  
Reactive Power ◽  
Power Sharing ◽  
Voltage Quality ◽  
Control Scheme

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 Low-Voltage Ride-Through Operation of Grid-Connected Microgrid Using Consensus-Based Distributed Control

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2867 ◽  
Author(s):  
Woon-Gyu Lee ◽  
Thai-Thanh Nguyen ◽  
Hyeong-Jun Yoo ◽  
Hak-Man Kim
Keyword(s):  
Distributed Control ◽  
Reactive Power ◽  
Control Method ◽  
Low Voltage ◽  
Power Sharing ◽  
Consensus Algorithm ◽  
Stable Operation ◽  
Low Voltage Ride Through ◽  
Primary Layer ◽  
Secondary Layer

Since the penetration of distributed energy resources (DERs) and energy storage systems (ESSs) into the microgrid (MG) system has increased significantly, the sudden disconnection of DERs and ESSs might affect the stability and reliability of the whole MG system. The low-voltage ride-through (LVRT) capability to maintain stable operation of the MG system should be considered. The main contribution of this study is to propose a distributed control, based on a dynamic consensus algorithm for LVRT operation of the MG system. The proposed control method is based on a hierarchical control that consists of primary and secondary layers. The primary layer is in charge of power regulation, while the secondary layer is responsible for the LVRT operation of the MG system. The droop controller is used in the primary layer to maintain power sharing among parallel-distributed generators in the MG system. The dynamic consensus algorithm is used in the secondary layer to control the accurate reactive power sharing and voltage restoration for LVRT operation. A comparison study on the proposed control method and centralized control method is presented in this study to show the effectiveness of the proposed controller. Different scenarios of communication failures are carried out to show the reliability of the proposed control method. The tested MG system and proposed controller are modeled in a MATLAB/Simulink environment to show the feasibility of the proposed control method.

scholarly journals Multiloop low bandwidth communication-based power sharing control for microgrids

2020 ◽  
Vol 21 (2) ◽  
pp. 682
Author(s):  
Erum Pathan ◽  
Afarulrazi Abu Bakar ◽  
Mubashir Hayat Khan ◽  
Muhammad Asad ◽  
Haider Arshad
Keyword(s):  
Reactive Power ◽  
Power Sharing ◽  
Control Technique ◽  
Voltage Source ◽  
Computational Burden ◽  
Voltage Source Inverters ◽  
Control Techniques ◽  
Equivalent Impedance ◽  
Control Scheme ◽  
Virtual Impedance

<span>In parallel-connected inverter-based microgrids, the reactive power sharing accuracy can not have satisfactory results effortlessly. Mismatch in feeder impedances of the parallel-connected inverter-based microgrids is a significant cause of inaccurate reactive power-sharing. In voltage source inverters (VSI) based microgrids, especially for the islanded mode of operation, the conventional centralized or decentralized control techniques are not much helpful to control the voltage deviations due to impedance mismatch. Mismatch of the feeder impedance is compensated by the addition of fixed virtual impedance. Whereas, the change in the virtual impedance is compensated by adaptive virtual impedance-based control techniques which are helpful to mitigate power-sharing errors, but in most of the control schemes virtual impedance-based control mechanism needs pre-knowledge of feeder impedance which increases the computational burden. This paper presents a decentralized virtual impedance-based power sharing control. In the proposed control solution to mitigate reactive power sharing errors in distributed generation (DG) units, mismatch of the parallel-connected feeder impedance is equalized by regulating the addition of equivalent impedance to each DG inverter. Proposed control technique offers an independent implementation without any pre-knowledge of the feeder impedance. Hence, the implementation of the control scheme is a straightforward and computational burden is also reduced. Simulation results show the effectiveness of the control scheme. </span>

scholarly journals An accurate reactive power control study in virtual flux droop control

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 948-953
Author(s):  
Aimeng Wang ◽  
Jia Zhang
Keyword(s):  
Power Control ◽  
Reactive Power ◽  
Control Method ◽  
Power Sharing ◽  
Control Voltage ◽  
Droop Control ◽  
Reactive Power Control ◽  
Control Scheme ◽  
Static Performance ◽  
Virtual Flux

AbstractThis paper investigates the problem of reactive power sharing based on virtual flux droop method. Firstly, flux droop control method is derived, where complicated multiple feedback loops and parameter regulation are avoided. Then, the reasons for inaccurate reactive power sharing are theoretically analyzed. Further, a novel reactive power control scheme is proposed which consists of three parts: compensation control, voltage recovery control and flux droop control. Finally, the proposed reactive power control strategy is verified in a simplified microgrid model with two parallel DGs. The simulation results show that the proposed control scheme can achieve accurate reactive power sharing and zero deviation of voltage. Meanwhile, it has some advantages of simple control and excellent dynamic and static performance.

Effective Communication-Based Reactive Power Sharing Scheme for Meshed Microgrid in an Islanded Mode

2021 ◽  
Author(s):  
Anitha Daniel ◽  
Suchitra Dayalan
Keyword(s):  
Power System ◽  
Reactive Power ◽  
Local Area ◽  
Power Sharing ◽  
Matlab Simulation ◽  
Distributed Generators ◽  
Control Scheme ◽  
Islanded Mode ◽  
Radial Network ◽  
Virtual Impedance

Microgrids (MGs) are the most sought out and feasible solution for the present energy crisis. MG is a group of Distributed Generators (DGs) interacting with each other to provide energy to a defined local area. The inclusion of DGs into the conventional power system at various voltage levels has altered the topology of the power system and their control techniques. Hence, the MGs can no longer be considered as a traditional radial network but rather a meshed network. The control and operation of such practical MGs become a challenge, especially when operated in the islanded mode. This research paper considers a realistic meshed MG operating in an islanded mode for study. In an islanded MG, the issues of real and reactive power sharing among DGs are addressed so that the power contribution of each DG is proportional to its rating, thus preventing overload and ensuring reliable operation. A communication-based virtual impedance estimation is proposed in addition to the droop controller for proportionate real and reactive power sharing among DGs in a meshed MG. With the increased complexity of meshed MG, the proposed communication-based control scheme offers an efficient reactive power sharing between DGs without the feeder and network impedance requirements. A MATLAB simulation study proves the effectiveness of the proposed control strategy for a meshed MG with equal DG ratings and unequal DG ratings under changing load conditions.

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