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Energy, Ecology and Environment

, Volume 4, Issue 5, pp 222–232 | Cite as

New model of multi-parallel distributed generator units based on virtual synchronous generator control strategy

  • Y. Daili
  • A. HarragEmail author
Original Article
  • 32 Downloads

Abstract

Virtual synchronous generator (VSG) control technique presents a promising alternative for controlling the inverter-based distributed generator (DG), due to its capability to improve the microgrid stability when the renewable energy has a high penetration level into the grid. The analyses and parameters design of the active and reactive power loop of DG are often based on a small-signal model, where a linear relationship between active and reactive powers versus control variables is obtained based on quasi-static method, in which the currents dynamic is neglected. This model gives qualitative results only in case of large conventional synchronous generators. However, for a small DG based on VSG controller with a small virtual inertia, fast power electronics devices and with coupling between active and reactive powers loops, this model does not give satisfactory results. To overcome the aforementioned problem, this paper proposes a new model of DG systems based on VSG operating in island microgrids. The proposed model incorporates the line impedance dynamic of the microgrid into the DG model. The accuracy of the proposed model has been investigated and compared with the conventional one using MATLAB/Simulink environment. Simulation obtained results prove that the new model is more precise compared to the conventional one in transit state reflecting by the way better the dynamics of the system and allowing as a consequence of a good analysis of the stability and behaviour of the global system.

Keywords

Virtual synchronous generator (VSG) Microgrid Power electronics converter Renewable energy sources Distributed generator Grid stability 

Abbreviations

VSG

Virtual synchronous generator

DG

Distributed generator

SG

Synchronous generator

PCC

Point of common coupling

VSI

Voltage source inverter

CSI

Current source inverter

List of symbols

LF

Inductance of the inverter filter

CF

Capacitance of the inverter filter

RL

Line resistance

XL

Line reactance

ZL

Line impedance

Vm

Inverter voltage magnitude

Vg

Grid voltage magnitudes

θm

Virtual mechanical phase

θg

Grid voltage phase

Pout

Injected active power

Qout

Injected reactive power

Vgdq

Voltage at the PCC in dq reference frame

Igdq

Current at the PCC in dq reference frame

D

Virtual damping coefficient

J

Virtual inertia

Pin

Input active power

Qout

Input reactive power

ωm

Virtual mechanical velocity

ωg

Grid angular velocity

Pref

Active power reference

ω0

No-load angular velocity

Kp

Frequency droop regulator coefficient

V0

No-load voltage magnitude

Kq

Reactive droop regulator coefficient

Ki

Voltage regulator integral coefficient

Qref

Reactive power reference

δ

Load angle

Δ

Small perturbations of the variable

Subscripts

0

Equilibrium operating point

out

Output

in

Input

dq

Direct and quadratic axis

ref

Reference

m

Mechanical

g

Grid

L

Line

F

Filter

Notes

Acknowledgements

The Algerian Ministry of Higher Education and Scientific Research (Research PRFU Project A01L07UN190120180005) supported this research.

Compliance with ethical standards

Conflict of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest.

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Copyright information

© The Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University 2019

Authors and Affiliations

  1. 1.LAS Laboratory, Electrical Engineering Department, Faculty of TechnologyFerhat Abbas UniversitySetifAlgeria
  2. 2.Optics and Precision Mechanics InstituteFerhat Abbas UniversitySetifAlgeria
  3. 3.CCNS Laboratory, Electronics Department, Faculty of TechnologyFerhat Abbas UniversitySetifAlgeria

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