Induction heating system, induction heating method, output monitoring apparatus, output monitoring method, and induction heating apparatus

Abstract

An induction heating system includes induction heating apparatuses, each including a high-frequency current transformer, a low-frequency current transformer and a heating coil, a high-frequency input switch connected to the high-frequency current transformer, a low-frequency input switch connected to the low-frequency current transformer, a first power source to output a high-frequency electric power and a low frequency electric power, a second power source, a first power source output switch connectable to the first power source, a second power source output switch connectable to the second power source, and a switch controller. Each induction heating apparatus includes a heater controller to send a signal to the switching controller to turn on one of the first power source output switch and the second power source output switch, to turn off the other, and to switch on or off each of the high-frequency input switch and the low-frequency input switch.

1 . An induction heating method comprising:
 providing a plurality of induction heating apparatuses each having a heating coil, a first power source configured to adjust a ratio of a high frequency output time and a low frequency output time with respect to an output period and to output a high-frequency electric power and a low frequency electric power, a second power source configured to output an electric power of a frequency that is different from a frequency of the electric power output from the first power source, and a switching section;   operating the switching section from one of the induction heating apparatuses to select one of a first mode, a second mode, a third mode, and a fourth mode; and   induction heating a workpiece arranged on said one of the induction heating apparatuses,   wherein, in the first mode, said one of the induction heating apparatuses receives one of the high-frequency electric power and the low frequency electric power from the first power source,   wherein, in the second mode, said one of the induction heating apparatuses receives the electric power from the second power source,   wherein, in the third mode, said one of the induction heating apparatuses receives electric power of different frequencies from the first power source by a time-division method; and   wherein, in the fourth mode, said one of the induction heating apparatuses receives one of the high-frequency electric power and the low frequency electric power from the first power source and the electric power from the second power source in a superimposed manner.