A Stationary Reference Frame Grid Synchronization System for Three-Phase Grid-Connected Power Converters Under Adverse Grid Conditions

Grid synchronization algorithms are of great importance
\nin the control of grid-connected power converters, as fast and
\naccurate detection of the grid voltage parameters is crucial in order
\nto implement stable control strategies under generic grid conditions.
\nThis paper presents a new grid synchronization method for
\nthree-phase three-wire networks, namely dual second-order generalized
\nintegrator (SOGI) frequency-locked loop. The method is
\nbased on two adaptive filters, implemented by using a SOGI on
\nthe stationary αβ reference frame, and it is able to perform an excellent
\nestimation of the instantaneous symmetrical components of
\nthe grid voltage under unbalanced and distorted grid conditions.
\nThis paper analyzes the performance of the proposed synchronization
\nmethod including different design issues. Moreover, the
\nbehavior of the method for synchronizing with highly unbalanced
\ngrid is proven by means of simulation and experimental results,
\ndemonstrating its excellent performance.