DC Microgrids: Benefits, Architectures, Perspectives and Challenges

Abstract

One of the major paradigm shifts that will be predictably observed in the energy mix is related to distribution networks. Until now, this type of electrical grid was characterized by an AC transmission. However, a new concept is emerging, as the electrical distribution networks characterized by DC transmission are beginning to be considered as a promising solution due to technological advances. In fact, we are now witnessing a proliferation of DC equipment associated with renewable energy sources, storage systems and loads. Thus, such equipment is beginning to be considered in different contexts. In this way, taking into consideration the requirement for the fast integration of this equipment into the existing electrical network, DC networks have started to become important. On the other hand, the importance of the development of these DC networks is not only due to the fact that the amount of DC equipment is becoming huge. When compared with the classical AC transmission systems, the DC networks are considered more efficient and reliable, not having any issues regarding the reactive power and frequency control and synchronization. Although much research work has been conducted, several technical aspects have not yet been defined as standard. This uncertainty is still an obstacle to a faster transition to this type of network. There are also other aspects that still need to be a focus of study and research in order to allow this technology to become a day-to-day solution. Finally, there are also many applications in which this kind of DC microgrid can be used, but they have still not been addressed. Thus, all these aspects are considered important challenges that need to be tackled. In this context, this paper presents an overview of the existing and possible solutions for this type of microgrid, as well as the challenges that need to be faced now.

Enhancing Microgrid Operation Through Electric Vehicle Integration: A Survey

“…AC technology is well established and certified, whereas DC technology is still growing. This indicates a shortage of experts who have conducted in-depth studies on DC MGs [97].…”

Microgrids Overview and Performance Evaluation on Low-voltage Distribution Network

“…In HMG, AC, and DC elements are separately integrated into their respective sections, therefore grid harmonization is not required for the energy generation and storage components. Since AC and DC elements are separately integrated into their respective sections in HMG, grid harmonization is not required for the energy generation and storage segment [52][53][54]. Combining the advantages of ACMG and DCMG, HMG enhances the network's reliability and efficiency and enables easy integration of different RESs and ESSs into the existing distribution network [27,55,56].…”

Fuzzy Approach for Managing Renewable Energy Flows for DC-Microgrid with Composite PV-WT Generators and Energy Storage System

“…MGs, depending on the operating mode, can be divided into direct current (DC-MG) [7][8][9] and alternative current (AC-MG) microgrids. Compared to the AC-MGs, the DC-MGs, which also operate in isolated mode, provide better performance regarding the management of energy flows coming from RESs (photovoltaic (PV), wind (WT), fuel cell (FC) [10]) with storage systems [11] towards electrical loads both civil and industrial without the need for DC/AC converters for the integrated system and without requiring synchronization operations [12][13][14].…”