Experimental Study of the Isolated Operation of a Home DC Link System

Abstract

This study focused on isolated power operation in a domestic home during a blackout. This type of operation has attracted much attention along with the growing availability of renewable energy technologies such as photovoltaic (PV) panels and battery energy storage systems (BESSs). Isolated operation needs to afford long-term sustainability even though the blackout situation may be limited. Thus, it is desirable to charge the BESS with generated power as far as possible. Recently, hybrid-type power conditioner systems (PCSs) have appeared on the market that are connected to a PV and BESS on the direct current (DC) side, known as a DC link system. The system enables the charging of the BESS with output from the PV regardless of the capacity of the PCS.Experiments were conducted to verify the effectiveness of isolated operation using a DC link system. The three types of renewable power generation equipment(PV, BESS, and Fuel Cell (FC)) were used to supply power in an experimental smart home along with plausible blackout scenarios. The results suggested that the DC link system could contribute to continuous isolated power operation. In comparison with a conventional system, isolated operation using the DC link system could direct more surplus power from the PV to charging the BESS. On the other hand, the FC stopped in some cases, and additional experiments were conducted. The results identified issues to be solved for a stable power supply during isolated operation.