Power sharing analysis of power-based droop control for DC microgrids considering cable impedances

This paper introduces a power-based droop controller for parallel operation of distributed energy resources in dc microgrids. This controller achieves power flow control when the bus voltage is imposed by a grid-interface converter that links the microgrid to an upstream grid. In such a case, accurate load distribution is allowed regardless of cable impedances. On the other hand, the proposed controller is able to provide bus voltage support like a classical droop controller, but precise power sharing is no longer ensured in this operation. Cable impedances taken into account, power sharing performance of power-based droop controller is analyzed and compared with that of traditional droop controller. Furthermore, the design procedure of the proposed controller is also presented herein. The simulation test based on Matlab/Simulink and the experimental test implemented on a laboratory-scale dc microgrid prototype are carried out to verify the performance of power-based droop controller.