Small-Signal Stability Analysis of PV-Based Synchronverter Including PV Operating Modes and DC-Link Voltage Controller

A virtual synchronous generator (VSG) is one of the promising solutions today for integration of renewable energy sources to the grid. Photovoltaic (PV) power generation is dominating most of the generation in renewable energy. In this scenario, it is imperative to study the combined dynamics of the PV source and the VSG in the grid connection mode. This article presents a study of such a PV power system, which is connected to a grid. The dc-link capacitor is considered as an energy storage (ES) element, which is generally the case in most of the practical systems. The synchronverter control scheme is taken as a VSG model. The small-signal model is obtained for the system under study, which mainly includes PV source and dc-link voltage controller dynamics. From the eigenvalues, which are obtained by using the small-signal model, analysis is carried out to find the effect on system dynamics due to the variation in different system parameters. Furthermore, the effect of maximum power point (MPP) and non-MPP modes on system dynamics is studied. The proposed model is validated through simulation in PSCAD/EMTDC and Controller Hardware In Loop (CHIL) in a Real Time Digital Simulator (RTDS).