Review
Cooperative Control of Microgrids: A Review of Theoretical
Frameworks, Applications and Recent Developments
Edward Smith
1,
*, Duane Robinson
1
and Ashish Agalgaonkar
2
Citation: Smith, E.; Robinson, D.;
Agalgaonkar, A. Cooperative Control
of Microgrids: A Review of Theoretical
Frameworks, Applications and Recent
Developments. Energies 2021, 14, 8026.
https://doi.org/10.3390/en14238026
Academic Editors: Pierluigi Siano,
Hassan Haes Alhelou and Amer
Al-Hinai
Received: 20 October 2021
Accepted: 24 November 2021
Published: 1 December 2021
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1
Australian Power Quality & Reliability Centre, University of Wollongong, Wollongong, NSW 2522, Australia;
duane@uow.edu.au
2
School of Electrical, Computer & Telecommunications Engineering, University of Wollongong,
Wollongong, NSW 2522, Australia; ashish@uow.edu.au
* Correspondence: ejs760@uowmail.edu.au; Tel.: +61-417-218-943
Abstract:
The development of cooperative control strategies for microgrids has become an area of
increasing research interest in recent years, often a result of advances in other areas of control theory
such as multi-agent systems and enabled by rapid advances in wireless communications technology
and power electronics. Though the basic concept of cooperative action in microgrids is intuitively
well-understood, a comprehensive survey of this approach with respect to its limitations and wide
range of potential applications has not yet been provided. The objective of this paper is to provide
a broad overview of cooperative control theory as applied to microgrids, introduce other possible
applications not previously described, and discuss recent advances and open problems in this area of
microgrid research.
Keywords: cooperative control; microgrid; multi-agent systems; distributed energy resources
1. Introduction
The theory and application of microgrids has received much attention over recent
years, and they are widely recognized as an enabling concept for future electrical grids. In
comparison with isolated distributed energy resources, microgrids offer several advantages.
In particular, their ability to operate autonomously from the grid, either in isolation or as
“clusters”, is seen as a key advantage. Power electronic converters are increasingly being
utilized to interface energy resources to the grid, and allow for highly controlled power
flows and flexible operating strategies that are still the focus of much research, though
these create other potential issues for the grid. In this regard, research interests have
focused on inverter strategies that enable autonomous, or islanded, operation. For example,
introducing frequency and voltage droops [
1
] was an early innovation that emulates the
power sharing of synchronous machines without the need for communication links. Based
on these early innovations, microgrid control hierarchies have been defined [
2
], which
introduce additional control layers allowing for the management of power quality closer to
utility-prescribed norms, which emulate a conventional control hierarchy in large-scale
power systems. In a comprehensive review of research on microgrids [
3
], cooperative
control was identified as an important emerging topic. It is common for research articles
relating to microgrids to describe a control strategy as “cooperative”, yet the scope of these
works is wide-ranging, and often cooperative behavior is not in fact demonstrated in the
normally understood sense.
Introducing some level of information exchange, even if only between nearest neigh-
bors, allows for cooperative action to be used, and this is the principle of agent-based
control. The application of multi-agent systems (MAS) theory to microgrids is an active
research area [
4
]. Indeed, the use of MAS in microgrids includes system design, simula-
tion, capacity sizing, scheduling, protection, operation, and maintenance. Advances in
communications technology, particularly wireless networks, have been rapid and, together
Energies 2021, 14, 8026. https://doi.org/10.3390/en14238026 https://www.mdpi.com/journal/energies
