Predefined-Time Adaptive Virtual Synchronous Generator Secondary Control for Microgrids

The traditional secondary control method for virtual synchronous generators suffers from limitations such as slow dynamic response and poor adaptability under varying operating conditions, which significantly affect the reliability and stability of microgrids. To address these issues, this paper proposes an adaptive virtual synchronous generator secondary control method for microgrids based on predefined-time convergence. First, a predefined-time controller is designed, whose convergence time can be preset by the user, thereby resolving the problem of excessively long convergence times for frequency regulation and power sharing. Second, an adaptive inertia damping control method incorporating Gaussian functions is introduced to mitigate frequency fluctuations during disturbances in the microgrid system, effectively suppressing frequency deviations and enhancing microgrid stability. Finally, based on Lyapunov stability theory, the convergence of the proposed control method is rigorously proved, and its feasibility is validated through MATLAB/Simulink simulations. The results demonstrate that the proposed secondary control method reduces the frequency and active power convergence times by 0.98 s and 0.49 s, respectively, compared to traditional virtual synchronous generator secondary control methods. Additionally, it exhibits smaller frequency fluctuation magnitude during disturbances, enabling fast and smooth frequency recovery.