Abstract (EN):
Phasor estimation and symmetrical components estimation is a fundamental task in power electronics converters control. Power conditioning systems like active filters, universal power flow controllers, static compensators, and dynamic voltage restorers, among other ones, need accurate synchronization circuits capable of dealing with very different grid voltage perturbations. Voltage sags and swells, harmonics, spikes and notches, frequency variation, phase steps, DC components and noise, are phenomena that can cause severe malfunction in the control or supervision circuits of such power systems. Additionally, some protection systems are sensitive to some of these parameters and can give wrong actions when they are not expected to. The DFT algorithm is one of best performers in phasor estimation, but is not perfect. The paper accurately describes the DFT errors under frequency variation, decaying DC components and harmonics, and analyzes the instantaneous phasor estimation, with absolute and recursive algorithms. Strong grid voltage perturbations, occurring in weak grids, especially in the grid connection of renewable energies, demand for a DFT-based robust estimation method. The proposed method, as demonstrated by extensive simulations, is capable of handling general grid voltage perturbations, imposing a compromise between dynamic response and accuracy.
Idioma:
Português
Tipo (Avaliação Docente):
Científica
Contacto:
ajm@fe.up.pt