IJIRST –International Journal for Innovative Research in Science & Technology| Volume 4 | Issue 5 | October 2017 ISSN (online): 2349-6010 All rights reserved by www.ijirst.org 24 An Unbalanced voltage Compensation Strategy for Islanded Microgrids by using Fuzzy Logic Controller G. Naresh K. V. Sateesh Babu M. Tech. Student (DFM) Assistant Professor Department of Electrical & Electronics Engineering Department of Electrical & Electronics Engineering MITS, Andhra Pradesh, India MITS, Andhra Pradesh, India Abstract In this paper, a control technique with low bandwidth transmission correspondences for paralleled three-phase inverters is proposed to accomplish palatable voltage unbalance compensation. The proposed control calculation principally comprises of voltage/current impedance loop controllers, a droop controller, a particular virtual impedance loop, and an unbalance compensator. The inward circle controllers depend on the stationary reference frame to better alleviate the voltage mutilation under nonlinear loads. Droop control and particular virtual impedance loop accomplish exact current-sharing when supplying both linear and nonlinear loads. In addition, by altering voltage references concurring to the adequacy of the negative sequence voltage, the unbalance component, which is for the most part created by single phase generators/loads, can be alleviated to an extreme low value. At last, an AC microgrid which incorporates three-phase three-leg inverters was tried to accept the proposed control technique. Keywords: Microgrids, voltage unbalance compensation, virtual impedance, droop control _______________________________________________________________________________________________________ I. INTRODUCTION As of late, dispersed energy resources (DERs, for example, wind turbines, photovoltaic systems and small scale turbines, have pick up an incredible expanding enthusiasm since they are monetary and environment amicable. When all is said in done, power electronic converters are utilized as interfaces amongst DERs and the grid [1], to such an extent that electrical power with great quality and high dependability can be conveyed to the heap or utility grid, as appeared in Fig. 1. This paper concentrates on islanded microgrids where the interfacing converters for the most part work as voltage sources to take an interest on the voltage and frequency direction while sharing at the same time active and reactive power precisely by conforming output voltage phase angles and amplitudes. Be that as it may, it is too favored that those converters could give power quality administration capacity, in a manner that we can take full utilization of the converters accessible limit. It is outstanding that power quality issues, particularly voltage/current unbalances and voltage/current distortions have turned out to be increasingly genuine in cutting angle power system. For example, in islanded microgrids, the voltage unbalance issue is a notable issue basically created by the utilization of single-phase generators/loads and it can lead to insecurity and power quality issues. Keeping in mind the end goal to improve the voltage waveform quality, a few segments to manage the voltage unbalance compensation have been produced, Fig. 1: General architecture of a microgrid.
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An Unbalanced voltage Compensation Strategy for Islanded ... · for example, static var compensator (STATCOM) [2], series active power filter [3] and shunt active power filter [4].
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IJIRST –International Journal for Innovative Research in Science & Technology| Volume 4 | Issue 5 | October 2017 ISSN (online): 2349-6010
All rights reserved by www.ijirst.org 24
An Unbalanced voltage Compensation Strategy
for Islanded Microgrids by using Fuzzy Logic
Controller
G. Naresh K. V. Sateesh Babu
M. Tech. Student (DFM) Assistant Professor Department of Electrical & Electronics Engineering Department of Electrical & Electronics Engineering
MITS, Andhra Pradesh, India MITS, Andhra Pradesh, India
Abstract
In this paper, a control technique with low bandwidth transmission correspondences for paralleled three-phase inverters is proposed
to accomplish palatable voltage unbalance compensation. The proposed control calculation principally comprises of
voltage/current impedance loop controllers, a droop controller, a particular virtual impedance loop, and an unbalance compensator.
The inward circle controllers depend on the stationary reference frame to better alleviate the voltage mutilation under nonlinear
loads. Droop control and particular virtual impedance loop accomplish exact current-sharing when supplying both linear and
nonlinear loads. In addition, by altering voltage references concurring to the adequacy of the negative sequence voltage, the
unbalance component, which is for the most part created by single phase generators/loads, can be alleviated to an extreme low
value. At last, an AC microgrid which incorporates three-phase three-leg inverters was tried to accept the proposed control
technique.
Keywords: Microgrids, voltage unbalance compensation, virtual impedance, droop control
An Unbalanced voltage Compensation Strategy for Islanded Microgrids by using Fuzzy Logic Controller (IJIRST/ Volume 4 / Issue 5/ 004)
All rights reserved by www.ijirst.org 41
VI. CONCLUSIONS
In this paper, a novel direct voltage unbalance compensation control procedure for islanded microgrids has been researched. The
control structure incorporates two levels: a nearby controller and a direct voltage unbalance compensator. The local controller for
the most part deals with the bus voltage regulation what's more, the power sharing exactness, while the direct voltage unbalance
compensator adds to moderate the voltage unbalance at the PCC by controlling the voltage reference. The effectiveness of the
control plan has been approved with three LCL DG converters associated in parallel sharing a basic AC transport. The exploratory
results demonstrate that the negative sequence voltage can be all around stifled to the desired worth with a fulfilled load sharing
accuracy.
REFERENCES
[1] H. Nikkhajoei and R.H. Lasseter, “Distributed generation interface to the CERTS microgrid,” IEEE Trans. Power Del., vol. 24, no. 3, pp. 1598-1608, Jul.
2009. [2] Y. Xu, L.M. Tolbert, J. D. Kueck, and D.T. Rizy, “Voltage and current unbalance compensation using a static var compensator,” IET on Power Electron.,
vol. 3, no. 6, pp.977-988, Nov. 2010.
[3] P. S. Flannery, G. Venkataramanan, “Unbalanced voltage sag ridethrough of a doubly fed induction generator wind turbine with series grid-side converter,” IEEE Trans. on Ind. Appl., vol. 45, no. 5, pp. 1879-1887, Sep.-Oct. 2009.
[4] Y. Xu; L. M. Tolbert, and J. D. Kueck, “Voltage and current unbalance compensation using a parallel active filter,” IEEE Power Electron. Spec.Conf., pp.