A comparative study of different PLL techniques for synchronization of grid-connected converters under unbalanced and distorted grid conditions

The Synchronous Reference Frame Phase-Locked Loop (SRF-PLL) is a commonly used technique for synchronizing grid-tied converters. However, its performance suffers under unbalanced and distorted grid conditions. This paper presents experimental results comparing two alternative techniques to SRF-PLL. Results indicate remarkable improvement of over 77% in the accuracy of the estimation.