Droop control method based on fuzzy adaptive virtual resistance for DC microgrids

Abstract

DC microgrid is a high-efficiency and high-reliability solution for integrating energy sources, energy storage units and loads. Droop control method based on the virtual resistance is the most popular control method for DC micro grids (MGs). However, this method has two limitations: 1) unequal load sharing in case of unequal line resistances of converters; 2) DC bus voltage deviation with increasing the load. In this paper, in order to solve these limitations, a new control method based on fuzzy controller is proposed to determine instantaneous virtual resistance considering current sharing error and DC bus voltage deviation. In the proposed method, a low bandwidth communication network is used for current sharing of converters and DC bus voltage regulation. The performance of the proposed method has been investigated for difference line resistances and load changes. The simulation results show that the proposed control method leads to increasing load sharing accuracy and DC bus voltage restoration improvement.