Stability analysis of the slip mode frequency shift islanding detection in single phase PV inverters

Abstract

This paper presents the stability analysis of the slip mode frequency shift (SMS) islanding detection technique. The developed mathematical model is based on the precise dynamical equations of the closed-loop control system for a grid-connected inverter. In particular, singular perturbation theory is used to divide the closed-loop dynamics into subsections with different rates of change. It is proven that this system complies with the mathematical conditions of the singular perturbation theory, and then the system stability analyzed accordingly. Also, the stability analysis has been performed for two modes of operation: the grid-connected mode and the islanded mode. Experimental results are presented to validate the analysis.