Adaptive virtual synchronous generator control strategy for grid-forming inverter

As a key power source for maintaining islanded operation or supporting weak grids, grid-forming distributed generators (DGs) offer precise control and the capability to independently establish voltage and frequency. However, due to the absence of inherent physical inertia, their dynamic regulation performance under external disturbances remains inadequate. With the increasing penetration of distributed generators, this issue has become increasingly critical for system stability. In order to overcome this issue, an adaptive inertia–frequency regulation approach is developed, drawing on the concept of virtual synchronous generator (VSG) control. Within this method, the virtual inertia is dynamically modified in response to the extent of frequency deviation that occurs after a disturbance. A transfer function model is established based on the three-layer control architecture of the VSG, where the angular frequency deviation of the common bus serves as the input and the output frequency of the VSG as the output. The influence mechanism of virtual inertia on the output frequency characteristics and stability under external disturbances is analysed. To verify the effectiveness of the proposed adaptive inertia control method, a grid-forming VSG control system is modelled in Simulink and tested under multiple categories of frequency perturbations. Compared with the fixed-inertia strategy, the proposed method achieves better control performance.