| Summary: | This study focuses on an essential aspect of Virtual Synchronous Generator (VSG) control strategies - enhancing the control flexibility of grid-integrated renewable energy sources. VSG control strategies, by integrating the rotational inertia and damping coefficient parameters of conventional synchronous generators into inverter control, have bolstered the system's dynamic regulation capabilities. This paper further introduces an adaptive virtual inertia control strategy aimed at improving the performance of VSGs in power and frequency modulation. Initially, the research establishes a small-signal model of the virtual synchronous generator to analyze the impact of rotational inertia on system frequency and active power. Subsequently, by examining the power angle and frequency oscillation curves of synchronous generators, it investigates the interrelationship between virtual inertia, rate of change of angular frequency, and the magnitude of angular frequency variation. On this basis, principles for selecting virtual inertia suitable for varying conditions are formulated. An adaptive virtual inertia calculation formula and associated coefficients are designed accordingly. Simulation results from MATLAB/Simulink demonstrate that the proposed strategy allows for virtual inertia adjustments in response to different system states, effectively reducing the overshoot of active power and frequency, and shortening the time for the system to return to a steady state, thereby enhancing the control flexibility and controllability of the VSG. © 2023 IEEE.
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