A phase lock loop with tracking filter for synchronizing an electric grid

摘要

Methods and systems for synchronizing an electric grid having unbalanced voltages are provided. Voltage vectors may be synchronized in a phase-locked-loop configured to maintain synchronous operation of the grid even when the voltages are unbalanced. For example, a phase-locked-(oop may be coupled to one or more tracking filters designed to estimate a disturbance in an error signal of the voltages. The estimated disturbance(s) may be removed from the error signal before the phase lock loop determines an estimate of the grid frequency. Thus, adverse affects of voltage unbalance, such as abnormal current behavior, may be mitigated.