Instantaneous Sequence-Component Resolution of 3-Phase Variables and Its Application to Dynamic Voltage Restoration

A technique for decomposing instantaneous three-phase voltages and currents into sequence components has been described. The technique is based on a recursive weighted least squares procedure. The main advantage of the proposed technique is the use of the same covariance and gain matrices for resolving any number of three-phase variables into their respective sequence components. The proposed technique also estimates the dc offset in the sensed variable, and these are eliminated during the processing. Finally, the proposed technique has been implemented in a digital signal processor (DSP) and has been applied to the open-loop control of a laboratory-scale dynamic voltage restorer.