| 摘要 |
PROBLEM TO BE SOLVED: To protect an inverter circuit from an abnormal operation caused by moding oscillation of a magnetron. SOLUTION: The power source for magnetron driving includes: an inverter circuit 1 which has a resonance circuit having a semiconductor switching element 8 and a high voltage transformer 7 and a high voltage rectifying circuit 9 and supplies power to a magnetron 10 by switching on/off of the semiconductor switching element 8; and a controlling part 11 for controlling the on/off of the semiconductor switching element 8. The controlling part 11 has: a driving circuit part 13 for driving the semiconductor switching element 8; a switching controlling part 12 for controlling on/off timing; a current detecting part 14 for detecting a current of the magnetron 10; and a frequency analyzing part 15 for analyzing frequency components of the current detected by the current detecting part 14. When a reference wave component of an operation frequency out of the frequency components of the current of the magnetron 10 detected by the frequency analyzing part 15 becomes lower than a prescribed value, the controlling part sends an operation shutdown instruction to the switching controlling part 12. COPYRIGHT: (C)2011,JPO&INPIT
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