A digital phase-locked-loop for synchronization of single-phase sources with the utility grid

This paper presents an innovative digital phase-locked-loop (PLL) implementation that uses a moving average filter with a very high rejection on the fundamental frequency and its harmonics. This PLL is very versatile and can be used for synchronizing single-phase sources, control of drives, among others. Due to its fully digital implementation it has a low cost, short settling time and high immunity to noise, disturbances and harmonic components. The method can be applied directly to microprocessor controllers connected in smart grids. Numerical results confirm the efficiency of the developed PLL.