Distributed Secondary Adaptive Frequency Coordination and Oscillation Suppression Control of Heterogeneous VSGs in Islanded Microgrids

The concept of the virtual synchronous generator (VSG) is recognized as a crucial technology for addressing the challenges posed by the low inertia of power systems. However, in practical microgrids, the inertia parameters of VSGs may differ, fluctuate, or be unknown, and the inertia at their connection points can be affected by other devices. These uncertainties complicate the analysis of inertia characteristics and the development of compatible controllers. To address these issues, this article proposes a distributed secondary adaptive frequency coordination and oscillation suppression control method for heterogeneous VSGs in islanded microgrids. By incorporating an adaptive control parameter based on the rate of change of frequency and consensus tracking errors in the distributed control, our method can be conducted without relying on predetermined inertia parameters and can ensure consistent suppression of frequency oscillations. In addition, the permissible stable boundaries of the control parameters in the presence of delays are examined using a Lyapunov-Krasovskii candidate. The effectiveness of the proposed method is ultimately validated through simulation cases and hardware-in-the-loop experiments.