DC Voltage Stabilization in DC/AC Hybrid Microgrid by Cooperative Control of Multiple Energy Storages

This paper presents experimental study results compared with simulation study results for the voltage stabilization of a hybrid microgrid system, which may be possibly deteriorated by both integration of RES (Renewable Energy Sources) power generation and load variation. The experimental studies have been carried out by use of a small-scale prototype microgrid system that has been developed by Tohoku Gakuin University, Japan for the research and development of microgrid related technologies. In the proposed microgrid system, both DC and AC power can be directly supplied to the corresponding type of loads, and the degraded DC voltage due to RES and load power fluctuation is stabilized by cooperative control of two different types of energy storage, which are EDLC (Electrical Double Layer Capacitor) and secondary battery, respectively. In simulation studies, the microgrid model with the similar system configuration of experimental studies has been worked out, and simulations have been conducted for identifying the voltage stabilizing effect for the proposed microgrid system. This paper gives the results obtained from both experimental and simulation studies, and these results illustrate the DC voltage can be effectively stabilized by the cooperative control of energy storages.