POWER CONTROL APPARATUS CAPABLE OF PREVENTING FLICKER OF BRIGHTNESS CAUSED DUE TO FAILURE OF IGNITION OF THYRISTOR

PURPOSE: A power control apparatus is provided to prevent a flicker of brightness caused due to a failure of ignition of a thyristor. CONSTITUTION: A power control apparatus comprises a first phase control circuit(PC1), a second phase control circuit(PC2), and a control unit. The first phase control circuit includes self arc-suppressing control elements(Q1,Q2) inserted into an AC power line so as to phase control AC voltages. The second phase control circuit includes thyristors(T1,T2) inserted into an AC power line so as to phase control AC voltages. The control unit operates the self arc-suppressing control elements of the first phase control circuit at a desired phase of AC voltage half-wave by a slope control, supplies a short-time trigger signal for ensuring reset time prior to ending of AC voltage half-wave to the thyristors of the second phase control circuit when a load current is nearly saturated, and turns on the self arc-suppressing control elements.