A Reduced-Order Technique for Stability Investigation of Voltage Source Inverters

This paper presents a second order model for stability analysis of grid-connected voltage source inverters (VSIs). VSIs are commonly modeled as ideal voltage sources for analysis. However, this approach cannot guarantee accuracy since it does not take into consideration the dominant states of the inverter. In this paper, a reduced-order model based on balanced truncation method is derived from a comprehensive twelfth-order model for a grid-connected VSI. The developed second-order model is computationally modest while providing an accurate representation of the system characteristic. The efficacy of the developed model is verified through time-domain simulations and root locus studies of the model eigenvalues against its full-order counterpart.