Title :
Phase-Locked Loop Based on an Observer for Grid Synchronization
Author :
Yongsoon Park ; Seung-Ki Sul ; Woo-Chull Kim ; Hyun-young Lee
Author_Institution :
Seoul Nat. Univ., Seoul, South Korea
Abstract :
A grid synchronization technique is essential for grid-connected power converters. Phase-locked loop (PLL) has been widely exploited as an implementation technique, but additional efforts are required to deal with severely distorted grid voltages. In this paper, an observer is proposed to enhance the performance of PLL. A state equation is newly formulated to construct the observer, which extracts positive-sequence voltage from the distorted grid voltage. Additionally, guidelines are suggested to set the observer gains by considering its internal transfer functions. The PLL and proposed observer have been tested in simulations and experiments in contrast to dual second-order generalized integrator frequency-locked loop. The results have shown that the proposed method reveals a better phase-tracking performance for grid synchronization.
Keywords :
observers; phase locked loops; power grids; synchronisation; PLL; dual second-order generalized integrator frequency-locked loop; grid synchronization technique; grid-connected power converter; internal transfer function; observer; phase-locked loop; phase-tracking performance; positive-sequence voltage extraction; Equations; Frequency estimation; Mathematical model; Observers; Phase locked loops; Synchronization; Transfer functions; Digital signal processing; grid synchronization; grid-tied converter; observer; phase-locked loop (PLL); positive-sequence voltage;
Journal_Title :
Industry Applications, IEEE Transactions on
DOI :
10.1109/TIA.2013.2279194