Stability Analysis and Interaction-Rule-Based Optimization of Multisource and Multiload DC Microgrid

Coupling interaction within multisource and multiload (MSML) challenges the stable operation of dc microgrids. To disclose the essential mechanism, a detailed small-signal model of the MSML dc microgrid is established first. Then, the relations between coupling parameters and stability margin are investigated using modal analysis and participation factor. Two important corollaries are discovered: 1) in a three-source system, when the sources distribute in the two long and one short of the transmission lines, the system can achieve the largest stability margin; and 2) the increase of power sources will induce an impedance augmentation effect and improve the stability margin. Thus, an interaction-rule-based optimization method is proposed to adjust the controller parameters, which can not only raise damping and improve stability margin but also provide inertia for the system. Substantial theoretical analyses and hardware-in-the-loop experiments further verify these findings and the effectiveness of the proposed method.