Parameter Stability Region Analysis of Islanded Microgrid Based on Bifurcation Theory

This paper studies the parameter stability region of droop-controlled ac microgrid (MG) with static ZIP (constant impedance, constant current, and constant power) load and dynamic induction motor (IM) load using bifurcation theory. First, the dynamic model of the MG with ZIP and IM loads is developed. Next, bifurcation analysis is used to predict the bifurcation boundaries where MG becomes unstable. Saddle node and hopf bifurcation are detected in the studied system when parameters change. The stability region in parameters space is bounded by bifurcation boundaries. To improve the computing efficiency for predicting the stable region of parameters, the reduced-order models of MGs are developed based on singular perturbation method. Finally, numerical simulations and experiment are used to verify the analysis result and the effectiveness of the proposed strategy.