Comparison of Three Small-Signal Stability Analysis Methods for Grid-Following Inverter

Conventional vector current control (VCC) based grid-following inverters suffer from stability issues under weak grid, which attracts a lot of attention in recent years. Small-signal linearized model is an effective tool to analyze the stability of such nonlinear systems. In this paper, three small-signal stability analysis methods are compared, which are the state-space method, impedance analysis method, and equivalent single-input single-output (SISO) stability analysis method. These three methods are based on the same primitive system but with different input-output relations. Through strict analysis, it is found that the three methods basically predict the same stability boundary. Finally, the advantages and disadvantages of three methods are summarized and compared.