Abstract: The present invention is an AC voltage regulator which includes a feed-forward circuit and a differential amplifier which continuously and instantaneously compares the incoming AC voltage to a locally generated, amplitude-stabilized wave form. The local wave form is generated substantially frequency and phase synchronized to the incoming voltage. The output of the differential amplifier drives a power amplifier. The power amplifier output is arranged to continuously buck or boost the incoming AC voltage, depending on the polarity (phase) of the signal from the differential amplifier. The system corrects even subcycle disturbances in the incoming wave form. The present invention is also a method for regulating AC voltage.