Synchronization Method for Three Phase Applications

MAESTRI, S.O.; DONATO, P.; PETROCELLI, R.; CARUGATTI, I.; CARRICA, D.; BENEDETTI, M.

INTERNATIONAL REVIEW OF ELECTRICAL ENGINEERING-IREE

PRAISE WORTHY PRIZE SRL

Año: 2010 vol. 5 p. 1728 - 1735

1827-6660

Grid synchronization is critical for a large number of systems, being difficult toachieve in variable frequency or polluted environments. This article presents a simple and fastresponse digital signal processing method designed to obtain utility grid synchronism. Thismethod is based on varying the sampling frequency so as to generate sampling pulses at afrequency multiple of the main frequency and in phase with it. Even though it operates with avariable sampling frequency, a model in z-transform space is developed, which simplifies thedesign of the system controller. This feature makes it suitable for measuring harmonics in theutility grid and for obtaining the phase reference for applications such as on-line powerconverters. Design equations for a closed loop controller producing a critically damped responseare also developed herein. The method has been verified conducting experimental tests underdifferent disturbance conditions.