Microgrid architectures

This chapter presents a general description of microgrids (MGs), illustrating basic characteristics and structures of MGs with the objective of providing general background information on MGs that will help one to better understand the best promising structure and architecture in designing such systems. At present, AC MGs are still the main arrangement of MGs, even if they involve some drawbacks such as the need for synchronization of DG units, the circulation of reactive power and electromagnetic compatibility problems due to the intensive use of AC/direct current (DC) converters. Recently, DC MGs are emerging as a possible solution to avoid the aforementioned problems for a few isolated DC devices that must be connected into ex-novo networks. Although DC-powered components for residential and industrial applications are going to be more and more developed, the vast majority of existing devices currently in use in every area are fed in AC.