Fixed-time observer-based distributed secondary voltage and frequency control of islanded AC microgrids

Mohamed Ghazzali, Mohamed Haloua, Fouad Giri

Abstract


This paper deals with the problem of voltage and frequency control of distributed generators (DGs) in AC islanded microgrids. The main motivation of this work is to obviate the shortcomings of conventional centralized and distributed control of microgrids by providing a better alternative control strategy with better control performance than
state-of-the art approaches. A distributed secondary control protocol based on a novel fixed-time observer-based feedback control method is designed for fixed-time voltage and frequency regulation and reference tracking. Compared to the existing secondary microgrid controllers, the proposed control strategy ensures voltage and frequency regulation and reference tracking before the desired fixed-time despite the microgrid
initial conditions, parameters uncertainties and the unknown disturbances. Also, the controllers design and tuning is simple, straightforward and model-free.i.e, does not require a prior knowledge of the microgrid topology, parameters, loads or transmission lines impedance. The use of distributed control approach enhances the reliability of the system by making the control system geographically distributed along with the power sources, by using the neighboring DGs informations instead of the DG’s local informations only and by cooperatively rejecting external disturbances and maintaining the voltage and frequency at their nominal values at any point of the microgrid. A
comparative simulation study with some of the works that addressed distributed secondary voltage and frequency control is conducted to highlight the effectiveness of the proposed controllers in term of reference tracking and robustness to load power variations.

Keywords


Distributed observer; Fixed-time control; Microgrid; Secondary frequency control; Secondary voltage control



DOI: http://doi.org/10.11591/ijece.v10i5.pp%25p
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