Fundamental Characteristics of Laboratory Scale Model DC Microgrid to Exchange Electric Power from Distributed Generators Installed in Residential Houses

摘要

The DC microgrid is a novel power system using DC distribution in order to provide superhigh-quality power. This DC system is suitable for DC-output distributed generation and energy storage. In this research, we assumed one type of DC microgrid for residential houses (apartment house or housing complex). Each residence has a distributed generation facility such as a gas engine or fuel cell. These cogeneration facilities are connected to the DC power line, and the electricity from the cogeneration facilities can be shared among the residences. The hot water from the cogeneration facility is used in each residence. We constructed an experimental system based on this concept in our laboratory. We have studied the fundamental characteristics and the quality of the power supplied to the loads against several fluctuations or faults. The experimental results demonstrated that the system could supply highquality power to the loads despite sudden load variations and voltage sags of the utility grid. Afterwards, we moved the experimental system to an experimental apartment house (NEXT21). We studied the quality of power supply by using practical power lines, and confirmed that the system was also able to supply power to home appliances stably.