Modelling, analysis, and stability assessment of wind turbine generator connected to a low inertia AC-DC microgrid with frequency support capability

Recently, the integration of renewable energy sources and the development of hybrid AC-DC grids have become increasingly noticeable. Such modern power systems with high penetration of converter-based power sources face many challenges, such as the reduction in the overall system inertia. One of the popular methods to enhance the system's inertia is to utilize the energy stored in the rotors of wind turbine generators. Although many researchers have proposed effective strategies to address this problem. However, interaction dynamics that might arise between the connected components in a low-inertia AC/DC grid, considering the detailed modelling of each component, are not comprehensively addressed. Therefore, this paper presents a detailed modelling of a typical low-inertia AC/DC grid with frequency support capability offered by a wind generator. The overall system stability is evaluated with the help of the entire system state-space model. Additionally, the influence of varying system parameters on system dominant poles is analyzed to evaluate system stability margins. The study findings are justified through time-domain nonlinear simulations.