A DC micro-grid for superhigh-quality electric power distribution

The "DC Micro-grid" is a novel power system using DC distribution in order to provide superhigh-quality electric power. The DC distribution system is suitable for DC output distributed generation techniques such as photovoltaic and fuel cells, and energy storage forms such as batteries and electric double-layer capacitors. The power is distributed through a DC distribution line and converted to the required AC or DC voltage by converters placed near loads. The load-side converters do not need transformers due to the choice of the proper distributed DC voltage. The spread converter scheme helps to assure high-quality power supply. Even if a short circuit occurs on one load side, it does not affect other loads. In this paper, we propose a DC micro-grid configuration and converter control methods for generation and energy storage. Computer simulation results demonstrate seamless operation during turn-on and turn-off of distributed generation, transients at the times of connecting and disconnecting operation with the bulk power system, and stability against sudden large load variations. (c) 2008 Wiley Periodicals, Inc.