Stability Analysis of Master-slave Controlled AC Microgrids Based on Impedance Network Model

AC microgrids dominated by power electronic converters are prone to various types of oscillation problems and a comprehensive oscillation analysis of the system is required to effectively suppress and prevent them. To this end, this paper proposes an AC microgrid oscillation stability analysis method based on the frequency domain impedance network model, which can accurately reflect the oscillation characteristics of the system. Firstly, the impedance models for Vf control, PQ control and VdcIq control are established, based on which the equivalent impedance network model of the AC microgrid system is built. Secondly, a stability criterion based on determinants is established to analyse the oscillatory stability of the system. Finally, frequency scan and time domain simulation results are presented in MATLAB/Simulink to verify the effectiveness of the modelling and oscillation stability analysis methods.