Vector-synchronization-observer-based power support requirement recognition and control to improve grid frequency and voltage dynamics

This paper presents a vector-synchronization-observer-based powers support control approach for renewable power generations to improve the dynamic performance of grid frequency and voltage. In this paper the new power dynamic balance mechanism is attempted to be explored and the requirement of the dynamic power support of grid is recognized to from the three-phase voltage in the proposed strategy. In the proposed strategy, the phase and magnitude variation of grid voltage vector at the point of common coupling of renewable power generations is used to replace traditional grid frequency and voltage signal feedback in df/dt-control and ΔV-control to detect power requirement of grid more quickly. The variation of the voltage vector in magnitude and phase is detected by the amplitude-phase locked loop (APLL) to generated the additional active and reactive powers support command signal for renewable power generations to support grid voltage and frequency. Moreover, the small-signal stability is also enhanced by the proposed control method of DFIG-based wind turbines in weak grid. Finally, simulations were implemented to validate the improvement of grid frequency and voltage dynamics.