Low Voltage Direct Current Supply and Utilization System: Definition, Key Technologies and Development

With rapid increase of distributed solar power generation and direct current (DC) based loads such as data centers, electric vehicles (EVs), and DC household appliances, the development trend of the power system is changed from conventional alternate current (AC) to DC. Traditional AC power systems can scarcely meet the development demand of new DC trends, especially since both the generation side and load side are comprised of DC-based electronic power components. With this background, low voltage direct current supply and utilization system (LVDCSUS) has attracted more and more attention for its great advantages over an AC grid to overcome challenges in operation, reliability, and energy loss in renewable energy connection, DC load power utilization and a number of other aspects. However, the definition of the LVDCSUS is still not clear even though many demonstration projects have been put into planning and operation. In order to provide a clear description of LVDCSUS, first, the characteristics of LVDCSUS are illustrated in this paper to show the advance of the LVDCSUS. Second, the potential application scenarios of LVDCSUS are presented in this paper. Third, application of LVDCSUS technologies and some demonstration projects in China are introduced. Besides the development of the LVDCSUS, key technologies, including but not limited to planning and design, voltage levels, control strategies, and key equipment of LVDCSUS, are discussed in this paper. Finally, future application areas and the research orientations of LVDCSUS are analyzed.