| 摘要 |
PROBLEM TO BE SOLVED: To suppress fall of the power factor of an inverter circuit power supply by lessening distortion of the input current waveform, which originates at the time of change of the power supply voltage, in the high frequency heating equipment. SOLUTION: It has a booster transformer 30, which supplies high-voltage electric power to a magnetron 24, an inverter circuit 22, which rectifies the commercial electric power supply 21, and changes it into alternate current of a predetermined frequency to supply it to the booster transformer 30, and an output setting means 23. The inverter circuit 22 has a modulation part 27, a driving part 28, and a semiconductor switching element 29, and the modulation part 27 generates a modulation signal from a power supply voltage waveform detection means 25, which detects the voltage waveform of the commercial power supply 21, from which the inverter circuit 22 obtains electric power, a power supply voltage level detection means 26 to detect the voltage value of the commercial power supply 21, and the output setting means 23. The driving part 28 is made to have a composition, which determines a pulse signal for driving the semiconductor switching element 29 based on the modulation signal of the modulation part 27. |
