A Design and Optimization Tool for Inverter-Based Microgrids Using Large-Signal Nonlinear Analysis

In this paper, large-signal Lyapunov-based stability analysis is performed on an inverter-based microgrid. Most microgrid stability studies have been based on small-signal stability by using linearization techniques. This paper produces the large-signal nonlinear mathematical model of an inverter-based microgrid. The inverter models include the dc-side circuits associated with dc sources. The mathematical model is then used to estimated the domain of asymptotic stability of the microgrid. A three bus microgrid system is used as a case study to highlight the design and optimization capability of such an approach. This paper explores the effect of system component sizing, load transient, and dc-side voltage source variations on the asymptotic stability of the ac microgrid. Thus, this approach quantifies the effect of dc-side variations on the transient stability of the ac-side microgrid. Time domain simulations were used to illustrate the mathematical nonlinear analysis results.