A comprehensive review of DC electric spring structures for sustainable new-generation DC microgrids: Topologies, control methods, challenges and opportunities

The accelerating integration of Renewable Energy Sources to struggle climate change brings some challenges of instability, power imbalance because of their intermittent energy production characteristic. Also, most of RESs such as photovoltaic and wind have Direct Current (DC) output. Therefore, DC micro grids (DCMG) has become more popular with increasing in DC input load, such as information technology devices and electrical vehicles (EVs). Increasing use of DC loads and intermittent characteristic of RESs cause power quality problems such as power instability and voltage sag/swell in DCMG. These power quality challenges are crucial important in newgeneration DCMG because it affects to critical loads such as information technology devices. In order to solve this issue, DC electric spring (DCES), which are demand side management technology have been investigated. Most of researches on topologies, control methods and energy management systems, have been presented in literature since it was reported. This study aims to assist and provide guidance to researchers working in this field by reviewing and comparing the all existing studies in the DCES topologies for DCMG. The existing topologies are categorized and different methodologies used in the DCES system are detailed. Finally, challenges and opportunities have been summarized and emphasized for researchers' future works.