Stability Investigation of Three-Phase Grid-Tied PV Inverters with Impedance-Based Method

Abstract

This paper presents stability investigations of three-phase grid-tied photovoltaic inverter systems using the impedance-based method. Impedance models (IMs) are established considering different control loops, and passive elements. IMs with a current control in both synchronous and stationary frames are established and compared. Impacts of different control loops, filter parameters, operation point as well as the number of inverters in the system are discussed. It is possible to identify the reason of an instability with the IMs.