Abstract
This paper addresses the effects of current controller saturation on small-signal stability of microgrids when considering the dc side dynamics of inverters. The saturation effect is introduced with a sigmoid function, that restrains the output of the current controllers based on the physical limitations of the dc side of the DG units. A linearized state-space model is presented, and the equilibrium points of the state-space variables are obtained in the time domain. Then, the eigenvalues of the microgrid model are plotted on the s-plane, and their traces are investigated. A participation factor analysis indicates an increased sensitivity of the low-frequency modes to the gains of the voltage controllers that was not characterized before. This increased sensitivity points to a more restricted stability region, which imposes new limits to the bandwidth of the voltage controllers.