  Massive integration of power electronic devices with multiple control schemes
in a wide frequency range pose new challenges regarding systems stability and
reliability. Interactions between the fast control loops or between the fast
control loops and passive elements of the grid, have been reported in
literature and have led to introducing a new type of stability: the
Fast-Interaction Converter-driven Stability (FICDS). In this paper, factors
affecting the FICDS, such as tuning controller parameters, line parameters,
number of interconnected inverters, are explored in four microgrid topologies,
operating in grid connected and islanded mode. With the use of an impedance
based model which tracks the poles of the CDS transfer functions of each
system, their stability has been assessed. The obtained results have been
verified via time-domain simulations. Simulations from the islanded microgrid
of Gaidouromantra in Greece showcase the impact of the control parameters on
the operation of the system and indicate the need for further investigation.
