Cooperative control of DC microgrid storage for energy balancing and equal power sharing

This paper proposes a distributed multi-agent cooperative control system for dynamic energy balancing between storage devices in droop controlled DC microgrids. With the traditional droop control strategy, line resistances between DC microgrid energy storage devices and loads will cause unequal power sharing. The proposed control system modifies the output power of the droop controlled storage devices so that they reach a balanced energy level. Once a balanced energy level has been reached, the cooperative control system maintains equal power sharing between the storage devices. This ensures that the storage devices will not prematurely run out of energy, so their full output power capacity is available to regulate the microgrid voltage. Simulations have been completed showing that the cooperative control system is able to maintain voltage regulation in situations for which the traditional droop control fails.