Active Identification Method for Line Resistance in DC Microgrid Based on Single Pulse Injection

In dc microgrids, line resistance on the output side of the converters in parallel could lead to nonaccurate results for the traditional droop control method. In this letter, an active identification method for line resistance based on the dc microgrid specific system structure is proposed. By injecting a pulse disturbance actively and detecting the changes of output voltage and current, the line resistance between the paralleled converters and the dc bus could be obtained and used for the compensation of the droop coefficient. Compared with traditional droop control method and other improved methods, this method improves the current sharing accuracy and restores the dc bus voltage without any additional hardware devices to be added into the initial loop. Finally, simulation and experimental results supporting the feasibility and effectiveness of the proposed method are also presented.