JPS6412492A - High-frequency heating device - Google Patents

Abstract

PURPOSE:To shorten a heating time and to remove excessive quality in constitutional parts by equipping a power converter, which has one semiconductor element and changes commercial source power into high-frequency power, a semiconductor element controlling part, an electric wave radiation part, a start-up controlling part, and using a means for detecting a state ahead of the starting operation so as to provide a start-up signal. CONSTITUTION:A switching operation is given to a transistor 28 by a signal of a controlling part 34, so that a high-frequency voltage is generated on a primary coil 35 of a boosting transformer 27, and it is raised and rectified so as to oscillate a magnetron 32. A signal is sent to the start-up part 34 from a current detector 36. In the start-up part 34, a state ahead of the starting operation is detected by a thermistor, and an on time of the transistor 28 is controlled by the use of an error between this signal and a reference signal, so that an input current is kept to be a prescribed value and that an output of the magnetron 32 is controlled. When a heating start command 40 is given to a start-up controlling part 41, electromagnetic wave energy is generated with a large output for a prescribed time at the beginning of the operation in the part 41, so that a heating time can be shortened. Cooling function of constitutional parts and quality in heat-resisting specifications can be made appropriate to remove excessive quality.