Mitsui Engineering and Shipbuilding Company Limited

Takahiro Ao

Naoki Uchida

Keiji Kawanaka

Nobutaka Matsunaka

Kazuyoshi Fujita

An object is to provide an induction heating method having a high power factor in which when thermal processing is performed through a plurality of heating coils receiving the supply of the current to generate mutual induction. In an induction heating method using an induction heating device that includes self-resonant circuits which feeds currents of equal frequency to a plurality of heating coils receiving the supply of the current to generate mutual induction is connected, wherein adjustment or control is performed to carry out an operation such that a first ratio of a reactance component of a mutual induction impedance to a resistance component of the mutual induction impedance between the adjacent self-resonant circuits and a second ratio of a reactance component of a self-impedance to a resistance component of the self-impedance in the self-resonant circuit are made equal to each other.

Induction heating method

The present invention includes: a plurality of induction heating coils () which are disposed adjacently; capacitors () each of which is connected in series thereto; a plurality of inverters () each of which applies a high frequency voltage converted from a DC voltage to each series resonant circuit of the induction heating coil and the capacitor; and a control circuit () which operates the plurality of the inverters with a same frequency and current synchronization, controls so that a phase difference becomes minimal at a specific inverter, which supplies the maximum power to the plurality of the induction heating coils, between the high frequency voltage generated therefrom, and a resonant current flowing the series resonant circuit, and set a DC power supply voltage Vdc applied to the plurality of the inverters so that the output voltages (Vinv) become greater than mutual induction voltages (Vm).

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Tamano, Japan

Takahiro Ao