Droop based control strategy for balancing the level of hydrogen storage in direct current microgrid application

摘要

An adaptive droop control method based on level of stored hydrogen (LSH) is proposed in order to balance the LSH of each metal hydride (MH) hydrogen storage unit for DC microgrid application. In this methodology, the droop coefficient is inversely proportional to the nth order of the LSH in charging mode, whereas it is proportional to nth order of the LSH in discharging mode. The droop coefficient is modified according to the LSH of MH tanks and controls the power sharing between the FC generators using DC-DC converters. Simulation results confirm the effectiveness of the proposed control strategy. It is found that using the adaptive droop control method, fuel cell (in discharging mode) with higher LSH of MH tank delivers more power using DC-DC converter, while other fuel cell with lower LSH of MH tank provides less power. Load sharing speed between the fuel cell units can be adjusted by modifying the exponent n of LSH in droop control. This control strategy is very useful for the decentralized control of hydrogen storage based microgrid.