| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent the occurrence of an interference noise which is generated when a plurality of heating coils are operating at the same time. <P>SOLUTION: The first inverter 4 repeats alternately an operation mode 1 of obtaining output electric power P1 at an operation frequency f1, and an operation mode 3 of obtaining output electric power P3 lower than the P1 at an operation frequency f3 higher than the f1, by a control means 8, when the first and second inverters 4, 5 are operated at the same time, the second inverter 5 therein repeats alternately an operation mode 2 of obtaining output electric power P2 at an operation frequency f2, and an operation mode 4 of obtaining output electric power P4 lower than the P2 at an operation frequency f4 higher than the f2, the operation frequency f3 of the first inverter 4 is higher by 20 kHz or more than the operation frequency f2 of the second inverter 5, in the operation, the operation frequency f4 of the second inverter 5 is higher by 20 kHz or more than the operation frequency f1 of the first inverter 4, in the operation, and the operation mode 1 of the first inverter 4 and the operation mode 2 of the second inverter 5 are executed exclusively in each thereof. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
