Dual-frequency power-supply apparatus, high-frequency heating apparatus, and high-frequency quenching apparatus

Abstract

Provided are a dual-frequency power-supply apparatus, a high-frequency heating apparatus, and a high-frequency quenching apparatus having a high durability. A dual-frequency power-supply apparatusincludes a power supplythat alternately outputs a low-frequency current and a high-frequency current. The power supplyhas an inverterthat converts a direct current into the low-frequency current and the high-frequency current and a controllerthat controls the inverter. The controllerrepeats, in this order, a first output period Tin which the low-frequency current is output, a first intermission Tin which output is stopped, a second output period Tin which the high-frequency current is output, and a second intermission Tin which output is stopped. The controllersets the length of the first intermission Tlonger than a time Ta until the polarity of the output voltage of the power supplyis reversed fourthly after transition from the first output period Tto the first intermission T