Adaptive RoCoX droop control strategy for AC/DC hybrid microgrid

Abstract

With the increasing application of virtual inertia in microgrid design, AC and DC subgrids in hybrid microgrids (HMG) present diverse inertia characteristics. However, an HMG cannot achieve an optimal dynamic response by interconnecting multiple AC and DC virtual inertia scenarios. Therefore, a droop controller with a normalized rate of the change of DC voltage and AC frequency (RoCoX) is proposed to minimize the HMG's steady and dynamic deviations and reduce the power oscillation of the interlinking converter (ILC). The effect of the proposed controller on dynamic performance and equalization of RoCoX is analyzed using a small-signal model of an HMG with various inertias applied at both subgrids. The coefficient of the RoCoX controller is adaptively adjusted with the constraint of equalization of RoCoX and dynamic performance. The proposed method is verified using a Starsim hardware-in-the-loop experimental platform under various working conditions.