METHOD FOR ESTIMATING AND TRACKING FREQUENCY AND PHASE ANGLE OF 3-PHASE POWER GRID VOLTAGE SIGNALS

摘要

PROBLEM TO BE SOLVED: To provide a method for synchronizing and determining a phase angle of 3-phase voltage signals in a power grid in the presence of a voltage unbalance.

SOLUTION: Parameters of 3-phase voltage signals to synchronize a power grid in a presence of a voltage unbalance are estimated by: transforming the 3-phase voltage signals to αβ-reference signals using a Clark transformation matrix; estimating sinusoidal signals and corresponding quadrature signals of the αβ-reference signals using an extended Kalman filter; and determining a phase angle of a positive sequence based on a relationship of the phase angle to the estimated sinusoidal signals.

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