Energy Management Strategy for Supercapacitor in Autonomous DC Microgrid Using Virtual Impedance

With a proper energy management strategy (EMS), supercapacitor can be integrated into autonomous DC microgrid as an independent energy storage unit. The resulting microgrid could supply repeatedly quick bursts of electrical power without compromising power quality and lifetime of other distributed generations (DGs) or distributed energy storages. In this paper, a novel control strategy for supercapacitor is proposed. The method uses the virtual impedance loop to add a virtual resistor and a virtual capacitor connected in series between the converter and DC bus, which decouples power flow between supercapacitor and other DGs while ensuring the plug'n'play feature of supercapacitor (SC). The results show that the proposed EMS has a competing dynamic performance with excellent flexibility as compared to previous methods.