부산대학교 도서관

This paper presents a basic sensitivity analysis of the conversion losses in a dc microgrid by varying the system parameters. A simple residential apartment with 20 units with a photovoltaic (PV) system is taken for the analysis. The conversion losses are calculated with the measured electricity consumption and the estimated output of the PV system. Modelica, an object-oriented modeling language, was used as a simulation tool because of the flexibility in changing the system configuration and parameters. The simulation results show that the efficiencies of the converters in the system are almost directly proportional to the total system losses. Additionally, the rated capacity of the grid converter influenced the total losses linearly. It is also shown that the total rated capacity of the PV system has a relation to the advantages of dc microgrids compared to ac microgrids. These results reveal that the dc microgrid has an advantage regarding the loss reduction under suitable conditions. Additionally, this basic analysis will contribute to the design of system configurations and parameters for new dc microgrids.