The topic of microgrids (MGs) is a fast-growing and very promising field of research in terms of energy production quality, pollution reduction and sustainable development. Moreover, MGs are, above all, designed to considerably improve the autonomy, sustainability, and reliability of future electrical distribution grid. At the same time, aspects of MGs energy management, taking into consideration distribution generation systems, energy storage devices, electric vehicles, and consumption components have been widely investigated. Besides, grid architectures including DC, AC, or hybrid power generation systems, energy dispatching problems modelling, operating modes (islanded or grid connected), MGs sizing, simulations and problems solving optimization approaches, and other aspects, have been raised as topics of great interest for both electrical and computer sciences research communities. Furthermore, the United Nations Framework Convention on Climate Change and government policies and incentives have paved the way to massive electric vehicle (EV) deployment. Hence, several research studies have been conducted to investigate the integration of EVs in national power grid and future MGs. Specifically, EV charging stations’ bi-directional power flow control and energy management have been considerably explored. These issues index challenging research topics, which are in most cases still under progress. This paper gives an overview of MGs technology advancement in recent decades, taking into consideration distributed energy generation (DER), energy storage systems (ESS), EVs, and loads. It reviews the main MGs architecture, operating modes, sizing and energy management systems (EMS) and EVs integration.

Optimal Sizing and Energy Management of Microgrids with Vehicle-to-Grid Technology: A Critical Review and Future Trends

A review on recent developments in control and optimization of micro grids

Different types of distributed generation (DG) units based on renewable and non-renewable energy sources can create a local energy system in microgrids. The widespread penetration of distributed energy resources (DERs) has affected many power system issues, such as the control and operation of these networks. For the optimal operation of microgrids, optimal energy planning and management in the new space governing the distribution system requires extensive research and analysis. Getting acquainted with the latest research about the evaluation of the problems and challenges in the design of control systems plays an important role in providing a guidance map for researchers to find the recent challenges and propose new solutions. This paper tried to list the challenges of distributed generation sources for MG applications, opportunities, and solutions. These challenges are reported in hierarchical control strategies and power-sharing categories. Therefore, Model Predictive Control (MPC)-based approaches are reviewed for different recent control levels and power sharing strategies in a comprehensive and simple point of view. The performance comparison of MPC methods together and different allocated fitness functions and implementation algorithms are dedicated. Another hand, the potential of MPC methods to control inverters for increasing the reliability of the grid, which this feature could not be achieved by using conventional strategies, while has not been investigated by researchers widely, is introduced in a short review. Therefore, this paper shows an intersection guidance map for readers to facilitate future research works in these exciting and undiscovered fields.

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A Literature Review of the Control Challenges of Distributed Energy Resources Based on Microgrids (MGs): Past, Present and Future

Distributed generation (DG) is one of the essential segments of the arising microgrid idea that empowers sustainable power integration in a distribution network In DG unit activity, inverters assu

Comparative analysis of different control strategies in Microgrid

The introduction of photovoltaics (PV) based power generation has brought about the trend of residential rooftop PVs. Therefore the concept of energy market of buying and selling of power between the utility and consumers has been established. However, high penetration of PV causes congestion leading to voltage violation conditions, especially in case of grid fault that requires islanding of the PV systems. Furthermore, in case of radial distribution system (RDN), high PV penetration imposes over-voltage and under-voltage issues during peaking PV production and peak loading conditions respectively. Taking these into consideration, this paper proposes a voltage regulation methodology based on active-reactive power management through PV inverters. A PQ-V control curve is formulated for the PV inverters and corresponding tuning parameters are introduced for rapid voltage regulation using real-time measurements. The control strategy is evaluated on two scenarios of RDN based on different R/X ratios and nodes distances to validate its robustness.

A Reactive Power Compensation Strategy in Radial Distribution Network with High PV Penetration

The DC Microgrid concept has been flourishing in the recent times due to its intrinsic advantages like Renewable Energy Source (RES) compatibility, easier integration with storage utilities through Power Electronic Converters (PECs) and distributed loads. In-depth researches are going on in this field, as the concept of DC Grid can be considered as a master foundation in the realization of Smart Grid (SG) technologies. To achieve this, a number of constraints such as voltage regulation, islanding detection, allowable transient levels, etc. are to be met in accordance with globally accepted standards. The system should have a proper control scheme to keep the things reliable, fault-free and interoperable. In order to meet the constraints as per globally recognized standards, quite a few classes of control algorithms are adopted namely, Centralized, Decentralized and Distributed control. A standardized review of these control strategies is discussed as part of this work. A comparative study among these techniques is made so as to help a designer to choose the apt technique for controlling the microgrid.

https://www.ijrer.com/index.php/ijrer/article/download/9671/pdf

A Review on DC Microgrid Control Techniques, Applications and Trends

Numerical analysis using computational fluid dynamics is an affordable and effective method with increasing relevance every day in research and engineering problems. Choosing an appropriate convective discretization scheme is paramount importance for obtaining more accurate solutions using CFD methods. The present study compares two commonly used numerical convective schemes, the upwind scheme of Advection Upstream Splitting Method (AUSM) and the central schemes of Kurganov-Noelle-Petrova and Kurganov-Tadmor scheme (K-T) have been made to find the better central scheme. These two schemes are validated with inviscid 1D and 2D problems such as Sod’s shock tube, forward facing step in a Mach 3 tunnel, 15 Degree ramp in a Mach 2 supersonic tunnel, the Mach-reflection problem and scramjet engine operating under high Mach number. The AUSM and K-T schemes are robust enough to capture all the features of compressible flows. Comparison of results obtained by these 2 schemes is presented using density contours and surface property changes. It has been observed that both the schemes are robust enough to capture the flow features of the problems and that they have better accuracy for different conditions. 
HIGHLIGHTS 
 
This paper focuses on two convective flux discretization techniques i.e. the upwind scheme of AUSM and the central schemes of K-T and KNP 
Inviscid simulations for various problems in the supersonic as well as hypersonic regime were used in Sod’s 1-Dimensional Shock Tube, flow over forward facing step in supersonic wind tunnel and Mach 5 flow thorough scramjet engine 
The AUSM and K-T schemes are robust enough to capture all the features of compressible flows. It has been observed that both the schemes are robust enough to capture the flow features of the problems and that they have better accuracy for different conditions 
 
GRAPHICAL ABSTRACT

Mithun M. Krishnan

Papers

A Review on DC Microgrid Control Techniques, Applications and Trends

Numerical Analysis of High Speed Flow Applications using Various Flux Schemes