Three-Phase Grid-Synchronization: A Tracking-Filter In-the-Loop Apporach

This paper presents the design of a robust three-phase grid-synchronization scheme using tracking filters. The proposed scheme falls under the category of Synchronous Reference Frame (SRF) synchronization methodologies and employs a SRF-Phase Locked Loop (SRF-PLLs) structure with specifically designed building blocks. To ensure the convergence of the estimated grid angle under non-ideal input signal conditions, including DC bias and harmonics, a series of filters and signal conditioning techniques are employed. The performance of the proposed grid-synchronization scheme has been evaluated through testing under common grid disturbances, including frequency and angle jumps in the input signals.