Stability study of AC grid-connected quasi-Z-source inverter-based photovoltaic power systems

Abstract

The presence of photovoltaic power systems is currently increasing as green power sources, and quasi-Z-source inverters are commonly used to connect them to AC grids. However, stability concerns can appear due to inverters. Several studies address these concerns but they are not completely solved yet. This paper contributes with a simulation study about stability of AC grid-connected quasi-Z-source inverter-based photovoltaic power systems. The study is based on the PSCAD/EMTDC model of these systems and analyzes the influence of system parameters on subsynchronous and harmonic instabilities. Several solutions to improve these instabilities are discussed.