A nonlinear adaptive synchronization technique for single-phase grid-connected converters

This paper introduces a new adaptive notch filtering (ANF) approach as a powerful tool for synchronization of the single-phase converter-interfaced DG systems. The technique is simple and capable of extracting harmonics, tracking the amplitude and frequency variations, and providing the phase angle of the grid signal. The methodology is applicable for a wide range of equipment like converter- interfaced distributed generation (DG) units, e.g. wind, photovoltaic, fuel cells and micro-turbines, and also in active power filters and uninterrupted power supplies. Theoretical analysis is presented and the performance of the method is evaluated through simulation and experimental work.