DC Microgrid Stability Analysis Considering Time Delay in the Distributed Control

Abstract Bus voltage maintenance is the major concern for the stable operation of DC microgrids. Instead of a central controller based on global information, the distributed control strategy in DC microgrid can eliminate the bus voltage deviation with neighboring communication. However, the time delay among neighboring distributed generators (DGs) is inevitable. Besides, the bidirectional interactions in the distributed control process may make the time-delay stability more complicated. In order to consider the stability issues, this paper builds the time-delay dynamic model of DC microgrids with distributed control strategy, which can be considered as a neutral time-delay system model. A neutral linear matrix inequality (LMI) stability criterion is then provided to perform the time-delay stability analysis. Two indices namely maximum delay (MD) and time cost (TC) are defined to simultaneously consider the conservativeness and the speed of the method. Effectiveness and correctness of the proposed method are validated by a DC microgrid testbed finally.