Smart power management of DC microgrids in future milligrids

In this paper a novel droop approach for power management in low voltage dc MicroGrids (MGs) based on a master-slave concept is presented. A virtual frequency is injected by a master unit, which is proportional to its output power. Other slave units determine their output power according to the corresponding frequency based droop characteristics. Unlike the dc voltage-droop methods, the proposed virtual frequency-droop approach can be smartly applied for proportional power management among the energy units and loads as well as adding zero net energy capability to the MG. Both power flow and energy flow can be performed without utilizing an extra communication system. Simulation results validate the effectiveness of the proposed scheme.