| 摘要 |
PROBLEM TO BE SOLVED: To provide a control method for a high frequency power supply suitable for an inductively coupled heating plasma(ICP) torch. SOLUTION: In a voltage inverter for a high frequency power supply, the output of an inverter main circuit 14 is controlled by adjusting the phase angle of the inverter main circuit 14. First, the input power of the inverter main circuit 14 is monitored by a power monitoring circuit 53, while supplying a high frequency current based on the set value I1 of a current setter 51 to a work coil 2 from the inverter main circuit 14, and if the input current exceeds a designated value, a high frequency current based on the set value I2 (I2<I1) of a current setter 52 is supplied to a work coil 2 from the inverter main circuit 14. Thereby, damages caused by thermal expansion or the like of an ICP torch is prevented, and control response at the time of pulse modulation of the high frequency current can be speeded up. |
