Study on multiple hierarchical DC micro-grid based on photovoltaic generation systems

Micro-grid is suitable for popular utilization of distributed renewable energy generations. It can save grid-connected photovoltaic inverter and some rectifiers for DC loads when connecting photovoltaic generation to local loads by DC micro-grid, and the energy use efficiency increases dramatically. This paper proposed a multiple hierarchical DC micro-grid based on photovoltaic generations. The photovoltaic generations dispersed in different building roofs can be mutual backups while contacting them through DC micro-grid, and the energy storage devices have an easy access to connect in different forms, improving the system reliability and reducing the construction cost.