Modelling of distributed generation system based on virtual synchronous generator control technique

Abstract

Virtual synchronous generator (VSG) control method is considered as a suitable solution for controlling distributed generation (DG) system-based inverter, due to its ability to improve the microgrid stability. The VSG control method consists in controlling the power electronic interface-based DG unit to mimic the main dynamic of the conventional synchronous generator. Unlike, conventional synchronous generators, the load angle is not enough small in case of low and medium DG systems, moreover, they are usually connected to the grid through low and medium voltage lines, where the line impedance is not purely inductive, result in a strong coupling between active and reactive powers as well as nonlinearity between active and reactive powers functions and controls variables. This paper proposes a linear model of DG system with VSG controller based on a small signal analysis. The developed model has been investigated and compared with the detailed simulation model of a studied microgrid.