An efficient impedance stability analysis method for high-frequency stability of hybrid networking islanded-microgrid

Middlebrook impedance analysis method is considered to be an efficient method in analyzing the high-frequency stability. This method has the two deficiency: firstly, the partition between source and load subsystems is unclear; secondly, the analysis procedure is complicated. Partition between source and load subsystems in hybrid networking islanded-microgrid is researched in this paper. An efficient impedance stability analysis method is proposed in this paper to analyze instability of the hybrid networking islanded-microgrid caused by different length of line impedances, the inappropriate fast response of the inner loops and the interactions among paralleled inverters. Efficient analysis procedure and few judgments are maintained in proposed method. The feasibility of the proposed method and the effects of impedance on high-frequency stability are verified by the analysis and simulations.