Analysis of the effect of control bandwidth on inverter interactions using small-signal stability analysis

The penetration of power inverter connected renewable energy sources in the grid and in particular in distribution grids is growing day by day. This paper investigates, the stability of converters interacting in electrical islands through a small-signal model. More precisely, the impact of the bandwidth of the cascaded inverter controls of inverters operating in islanded grids is addressed by using modal analysis. The study relies on a detailed fundamental model of the power inverter and grid dynamics. The study shows that control interactions depend to a large extent on the system configuration, i.e., whether grid-forming and/or grid-feeding inverters are present in the islanded grid.