Abstract: A power control unit for a high-frequency dielectric heating not affected by variations in the magnetron type or characteristic, and power supply voltage fluctuation, etc., is provided. The power control unit for a high-frequency dielectric heating has an input current detection section 71, 72 for detecting input current of an inverter 10 for rectifying 31 an AC power supply voltage 20, performing high-frequency switching of the voltage, and converting the voltage to high-frequency power. The power control unit for a high-frequency dielectric heating converts a switching frequency control signal 92 provided by mixing input current waveform information 90 and power control information 91 into a drive signal of a semiconductor switching element 3, 4 of the inverter.

Abstract: A power control unit for a high-frequency dielectric heating not affected by variations in the magnetron type or characteristic, and power supply voltage fluctuation, etc., is provided. The power control unit for a high-frequency dielectric heating has an input current detection section 71, 72 for detecting input current of an inverter 10 for rectifying 31 an AC power supply voltage 20, performing high-frequency switching of the voltage, and converting the voltage to high-frequency power. The power control unit for a high-frequency dielectric heating converts a switching frequency control signal 92 provided by mixing input current waveform information 90 and power control information 91 into a drive signal of a semiconductor switching element 3, 4 of the inverter.

Abstract: A power control unit for a high-frequency dielectric heating not affected by variations in the magnetron type or characteristic, and power supply voltage fluctuation, etc., is provided. The power control unit for a high-frequency dielectric heating has an input current detection section 71, 72 for detecting input current of an inverter 10 for rectifying 31 an AC power supply voltage 20, performing high-frequency switching of the voltage, and converting the voltage to high-frequency power. The power control unit for a high-frequency dielectric heating converts a switching frequency control signal 92 provided by mixing input current waveform information 90 and power control information 91 into a drive signal of a semiconductor switching element 3, 4 of the inverter.

Abstract: An operating state detection technique is provided which makes it possible to accurately detect an abnormality of a high-frequency heating apparatus. An anode current detected by the anode current detection resistor 40 of a magnetron is inputted into the A/D converter terminal of a microcomputer 27 on a control panel circuit board side. The current is subjected to an analog-to-digital conversion to thereby obtain an anode voltage IaDC value. The microcomputer 27 determines an operating state based on a plurality of the anode voltage IaDC values thus read. Further, the microcomputer 27 obtains a summed value of the IaDC values corresponding to one period of the revolution of rotary antennas 68, 69 to thereby determines the operating state of the high-frequency heating apparatus 100 based on the summed value.

Abstract: An operating state detection technique is provided which makes it possible to accurately detect an abnormality of a high-frequency heating apparatus. An anode current detected by the anode current detection resistor 40 of a magnetron is inputted into the A/D converter terminal of a microcomputer 27 on a control panel circuit board side. The current is subjected to an analog-to-digital conversion to thereby obtain an anode voltage IaDC value. The microcomputer 27 determines an operating state based on a plurality of the anode voltage IaDC values thus read. Further, the microcomputer 27 obtains a summed value of the IaDC values corresponding to one period of the revolution of rotary antennas 68, 69 to thereby determines the operating state of the high-frequency heating apparatus 100 based on the summed value.

Abstract: A power control unit for high-frequency dielectric heating not affected by variations in the types or the characteristics of magnetrons, power supply voltage fluctuation, etc., is provided. The unit has an input current detection section 71, 72 for detecting input current of an inverter circuit 10 for rectifying 31 AC power supply voltage 20, performing high frequency switching, and converting into high frequency power, mixes input current waveform information 90 of the input current detection section and power control information 91 for controlling so that output of the input current detection section becomes a predetermined value in a mix circuit 81, outputs ON voltage information 92, makes a comparison between the ON voltage information and a sawtooth wave from a sawtooth wave generation circuit 83 in a PWM comparator 82, performs pulse width modulation, and outputs a drive signal for controlling turning on/off of a switching transistor 39 of an inverter circuit.

Abstract: A power control unit for high-frequency dielectric heating not affected by variations in the types or the characteristics of magnetrons, power supply voltage fluctuation, etc., is provided. The unit has an input current detection section 71, 72 for detecting input current of an inverter circuit 10 for rectifying 31 AC power supply voltage 20, performing high frequency switching, and converting into high frequency power, mixes input current waveform information 90 of the input current detection section and power control information 91 for controlling so that output of the input current detection section becomes a predetermined value in a mix circuit 81, outputs ON voltage information 92, makes a comparison between the ON voltage information and a sawtooth wave from a sawtooth wave generation circuit 83 in a PWM comparator 82, performs pulse width modulation, and outputs a drive signal for controlling turning on/off of a switching transistor 39 of an inverter circuit.

Abstract: A power control unit for high-frequency dielectric heating not affected by variations in the types or the characteristics of magnetrons, power supply voltage fluctuation, etc., is provided. The unit has an input current detection section 71, 72 for detecting input current of an inverter circuit 10 for rectifying 31 AC power supply voltage 20, performing high frequency switching, and converting into high frequency power, mixes input current waveform information 90 of the input current detection section and power control information 91 for controlling so that output of the input current detection section becomes a predetermined value in a mix circuit 81, outputs ON voltage information 92, makes a comparison between the ON voltage information and a sawtooth wave from a sawtooth wave generation circuit 83 in a PWM comparator 82, performs pulse width modulation, and outputs a drive signal for controlling turning on/off of a switching transistor 39 of an inverter circuit.

Abstract: A power control unit for high-frequency dielectric heating not affected by variations in the types or the characteristics of magnetrons, power supply voltage fluctuation, etc., is provided. The unit has an input current detection section 71, 72 for detecting input current of an inverter circuit 10 for rectifying 31 AC power supply voltage 20, performing high frequency switching, and converting into high frequency power, mixes input current waveform information 90 of the input current detection section and power control information 91 for controlling so that output of the input current detection section becomes a predetermined value in a mix circuit 81, outputs ON voltage information 92, makes a comparison between the ON voltage information and a sawtooth wave from a sawtooth wave generation circuit 83 in a PWM comparator 82, performs pulse width modulation, and outputs a drive signal for controlling turning on/off of a switching transistor 39 of an inverter circuit.

Abstract: The present invention is related to a high frequency heating apparatus for driving a magnetron such as a microwave oven, and has an object to provide a frequency modulating system capable of reducing power supply higher harmonic distortion of higher orders which are produced at phases in the vicinity of 0 degree and 180 degrees where an instantaneous voltage of a commercial power supply becomes the lowest voltage.

Abstract: A power control unit for a high-frequency dielectric heating not affected by variations in the magnetron type or characteristic, and power supply voltage fluctuation, etc., is provided. The power control unit for a high-frequency dielectric heating has an input current detection section 71, 72 for detecting input current of an inverter 10 for rectifying 31 an AC power supply voltage 20, performing high-frequency switching of the voltage, and converting the voltage to high-frequency power. The power control unit for a high-frequency dielectric heating converts a switching frequency control signal 92 provided by mixing input current waveform information 90 and power control information 91 into a drive signal of a semiconductor switching element 3, 4 of the inverter.

Abstract: An operating state detection technique is provided which makes it possible to accurately detect an abnormality of a high-frequency heating apparatus. An anode current detected by the anode current detection resistor 40 of a magnetron is inputted into the A/D converter terminal of a microcomputer 27 on a control panel circuit board side. The current is subjected to an analog-to-digital conversion to thereby obtain an anode voltage IaDC value. The microcomputer 27 determines an operating state based on a plurality of the anode voltage IaDC values thus read. Further, the microcomputer 27 obtains a summed value of the IaDC values corresponding to one period of the revolution of rotary antennas 68, 69 to thereby determines the operating state of the high-frequency heating apparatus 100 based on the summed value.

Abstract: Occurrence of a defect of the moding phenomenon, etc., accompanying rise in output of a magnetron after power down control is prevented and the reliability of a high-voltage dielectric heating apparatus is further improved. After power down control, when the temperature of a thermistor T1 falls again, the resistance value of the thermistor T1 increases and potential Vpc at a point PC also rises and when the potential Vpc becomes higher than Vc3 of another input potential of a comparator C3 (Vpc>Vc3), the comparator C3 outputs “0.” In association with this, a switch S2 is turned off and PD (power down) 2 of a resistor R7 is turned off and thus the input voltage to a positive terminal A and a negative terminal B of a comparator C1 is again restored to 3 V. When the temperature of the thermistor T1 further falls, the resistance value of the thermistor T1 increases and the potential Vpc at the point PC also starts to rise.

Abstract: It is an object of the present invention to provide a power supply for a high frequency heating that suppresses an over-shoot of an input current generated under an unstable state immediately after a magnetron begins oscillating. When processes from a non-oscillation to an oscillation of a magnetron (12) are finely classified, the non-oscillation (a start mode), the oscillation (a start mode) and the oscillation (a steady mode) are obtained. A problem resides in an unstable state immediately after the oscillation. When a PWM setting value at this time is set to a value lower than a PWM setting value in the steady mode, even if the PWM setting value during the steady mode is set to a maximum output value, the input current is not controlled to a large current including the over-shoot immediately after the oscillation.

Abstract: A booster transformer 100 for driving a magnetron includes a bobbin 11 on which at least a first winding 13 and a secondary winding 15 are wound and a core 19 inserted through the center of the bobbin 11, wherein a winding area of the secondary winding 15 is divided into two areas while interposing a partition wall 23, and an outer diameter d of a wire material of the secondary winding 15 and a width t1 of each of the divided winding areas are so set as to satisfy the relation t1<11d.

Abstract: An object of the invention is to provide a magnetron drive power supply for performing stable inverter operation and good in development efficiency. According to the invention, the potential difference between emitter terminal potential (121) of a switching element (12) and minus terminal potential (101) of a rectifying device (1) can be minimized and stable switching operation and abnormal voltage detection can be realized. There can be provided an optimum magnetron drive power supply responsive to the power supply voltage and good in development efficiency because of unification of chassis, etc., with commonality of component placements, particularly ground connection positions (41) and filament output positions (42) of a magnetron drive power supply in the rated voltage range of 100 V to 120 V and a magnetron drive power supply in the rated voltage range of 200 V to 240 V.

Abstract: The object of the invention is not only to simplify the structure of a high frequency dielectric heating power control apparatus and reduce the size of the apparatus but also to eliminate the need for control and design corresponding to the kind of a magnetron and thus enhance the running efficiency of the apparatus. An input current to an inverter circuit is detected by a shunt resistor 71 and is converted to an input current wave form through an input current signal amplifier 72. On the other hand, based on an alternating current power supply voltage wave form from an alternating power supply voltage, there is obtained through a gain variable amplifier 91 a reference wave form following the size of the input current wave form. A wave form error detect circuit 92 compares the input current wave form with the reference wave form to obtain a wave form error signal.

Abstract: A magnetron driving power source can detect the abnormal condition during no-load running with low cost and space saving. The magnetron driving power source includes a high voltage transformer (12) for supplying a high voltage to a magnetron (11), a switching part (13) for driving the high voltage transformer at a high frequency, a first control part (14) for giving a drive signal to the switching part, a second control part (16) for issuing an output command to the first control part, and a third control part (19) for correcting the output command in accordance with a decrease in the oscillation threshold value of the magnetron, wherein the first control part (14) performs a power down control in accordance with a signal from the third control part. Accordingly, the magnetron driving power source of the invention can treat the signal on the control side of the inverter and detect the abnormal condition during no-load running with low cost and space saving.

Abstract: A resonance type high frequency heating apparatus comprising; a direct current power supply; a series connection circuit consisting of a pair of semiconductor switching elements connected in parallel to the direct current power supply; another series connection circuit having a primary coil of a leakage transformer and a capacitor connected to both ends of one of the pair of semiconductor switching elements; and a drive means for driving each of the pair of semiconductor switching elements; wherein a variable dead time preparation circuit is provided in the drive means, and the variable dead time preparation circuit enables dead time to remain constant at below a predetermined frequency and causes the dead time to increase sharply at a point above a predetermined frequency.

Abstract: To attain a more reliable prevention of an electric shock by checking whether the earth states for two circuit boards are good. There is detected a voltage generated at an anode current sensing resistor 20 inserted into a path where the anode current of a magnetron 8 flows and a signal is transmitted to a microcomputer 27. The microcomputer 27 uses a selector switch 28 to determine the earth states for an inverter circuit board and a control panel circuit board before operation of a device. In case either one or both of the circuit boards are in a floating state, operation of a high-frequency heating device is inhibited. Otherwise, operation of the high-frequency heating device is permitted.