Large Signal Stability Criteria Combined with a 3D Region of Asymptotic Stability Method for Islanded AC/DC Hybrid Microgrids

Large disturbances frequently happen in isolated AC/DC Hybrid Microgrids. Unfortunately, constant power loads (CPLs) with negative impedance characteristics are equivalent to positive feedback, resulting an increase large disturbances. The system can easily become unstable. Consequently, signal stability criteria proposed this paper. Combined a three-dimensional region of asymptotic (3D RAS) method for islanded Microgrids, important parameters margins were determined. Firstly, mixed potential theory was used derive large-signal criterion. gave constraints on filtering parameters, CPL power, the battery charge and discharge, AC resistive loads, DC bus voltage. Then, Lyapunov functions constructed, Lasalle invariance principle adopted achieve 3D RAS. When emerged, simultaneously voltage current varied RAS, always obtained reached new steady-state equilibrium points. Finally, according comparisons, bigger capacitances capacitor capacitor, larger discharging smaller charging could significantly Simulations experimental data have shown that RAS work.