SOC-Based Adaptive Droop Control Considering the Line Impedance and Coordination Control for the Photovoltaic Dominated DC Microgrid

With the ascending popularity of renewable energy in power systems, DC microgrids offer an attractive solution to this trend. In order to prolong the lifetime and prevent excessive use of energy storage units in the DC microgrid, an adaptive droop control based on the state of charge of the energy storage unit is proposed considering the line impedance. By adaptively adjusting the droop coefficient, the mode transfer times between the shutdown mode and the droop control mode of the energy storage unit is reduced, and the loss caused by transfer among different modes is reduced. The reasonable power distribution of the energy storage unit is realized. The service cycle times of the energy storage unit are reduced and the bus voltage accuracy is improved. The proposed method in the DC microgrid is verified by simulation results.