An investigation of factors affecting Fast-Interaction Converter-driven stability in Microgrids

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.