DC-Bus Signaling Control Laws for the Operation of DC-Microgrids With Renewable Power Sources

DC-bus signaling (DBS) is a proven method to coordinate different microgrid agents, using the dc voltage of the microgrid as a communication signal. The droop control applied in a dc microgrid achieves accurate power-sharing among converters while leading to a certain voltage regulation error in the microgrid bus. The behavior of the different agents in a microgrid is managed by using the voltage at each node of the microgrid as the DBS signal. The technique proposed in this article uses an improved DBS technique to coordinate interlinking converters, photovoltaic generators, energy storage systems (ESSs), and loads in a microgrid. The operation of the renewable power sources of a microgrid at the full generated power is desired due to economic and environmental reasons. The DBS technique proposed in this article is adapted to integrate renewable power sources in the microgrid. The DBS-controlled ESSs will store the surplus energy if the generated power exceeds consumption. In the case of fully charged ESS, the renewable generators will limit their output power to those demanded by the loads. The proposed control laws have been tested in an experimental microgrid.