Adaptive droop controller design for energy management system in DC microgrid architectures

Abstract

In this study, the hierarchical two -level energy management system with an adaptive droop control approach is proposed for the microgrid system consisting of distributed generation units. The primary control layer controls the converters to transfer power from the distributed generation units as part of the hierarchical two -level control structure. The secondary control layer is used to improve current sharing accuracy and to provide DC bus voltage restoration. The DC microgrid system is analyzed using Th & eacute;venin's equivalent model and Kirchhoff's laws. The distribution generation units' current sharing parameters are obtained depending on the analysis results. The proposed adaptive droop control method is compared to the conventional droop control method. In the proposed system, the performance of the adaptive droop controller at 2250 W, where the demand is highest, is 9.65% better than the conventional method. Similarly, the proposed method performed 6.67% better in voltage regulation of the DC bus. The simulation results show that the designed control strategy increases the voltage restoration for the DC microgrid under variable operating conditions and provides better power sharing between the sources. Thus, the constraints of the conventional droop control method are improved by using the adaptive method.