A distortion-free phase-locked loop system for FACTS and power electronic controllers
Review articleOpen access
2007/06/01 Full-length article DOI: 10.1016/j.epsr.2006.09.013
Journal: Electric Power Systems Research
AbstractThis paper presents a single-phase phase-locked loop (PLL) system which is primarily free from the double-frequency ripples from which the conventional PLL system suffers. The proposed PLL is then extended to reject the harmonic components from the input signal and to estimate the phase-angle and frequency of the distorted input signal with no error. Three units of the proposed PLL can be used in three-phase power systems, such as FACTS and HVDC converters, to estimate the phase-angles of the individual phases with no double-frequency ripples and without sensitivity to the presence of harmonics and inter-harmonics. This makes the proposed PLL unique and desirable for applications which demand highly accurate estimation of the phase-angle(s) and frequency.
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