Conference paper Open Access
This paper proposed a secondary control method for power sharing accuracy enhancement and bus voltage restoration in DC microgrids. Droop control is notorious for its low power sharing accuracy when the cable resistance is considered. The virtual negative cable resistance (VNCR) concept is proposed compensate the cable resistance, therefore, it no longer has negative impact on the power sharing accuracy. The VNCR controller needs to monitor the DC bus voltage through low bandwidth communications. As the byproduct, the DC bus voltage restoration can be achieved simultaneously. The control signals are processed through low-pass filters, so the secondary control layer can be decoupled from the primary current/voltage controls over high frequency dynamics. Finally, the proposed VNCR method is validated through MATLAB simulation.