State-Space Modeling and Control of Grid-Tied Power Converters With Capacitive/Battery Energy Storage and Grid-Supportive Services

Advances in the fields of renewable generation, electric vehicles, and energy storage systems push forward the research on ac–dc and dc–ac grid-tied power converters. However, the variabilities of power converters create new challenges in modeling and control. Existing state-space models fail to accurately describe various types of grid-tied converters (GTCs), particularly those with grid-supportive services, which are increasingly required by upcoming grid codes. As such, this article first proposes to classify GTCs into four basic types according to their ac and dc characteristics. Subsequently, corresponding detailed state-space models of GTCs are introduced, which serve as a useful tool for stability analysis. On top of that, this article further proposes control implementations of grid-supportive services related to active and reactive power control, including droop, inertia, and oscillation damping. Finally, simulation and experimental results demonstrate the effectiveness of the proposed models and grid-supportive services.