Abstract: Timing of zero voltage in zero-voltage detector for detecting zero voltage of a commercial power supply 1 is predicted and input from the zero-voltage detector 6 is received only for a given time before and after the predicted timing, whereby overvoltage and overcurrent caused by a zero point shift can be prevented. Thus, it is provided a magnetron drive power supply which is excellent in stability for change in the power supply environment such as noise or instantaneous power interruption.

Abstract: It is provided a magnetron drive power supply wherein a series connection body of first and second semiconductor switch elements that can be brought into reverse conduction and a series connection body of first and second diodes are connected in parallel, first and second capacitors are connected in parallel to the first and second diodes, a series circuit of a commercial power supply and a primary winding of a high-voltage transformer is connected between a connection point of the first and second semiconductor switch elements that can be brought into reverse conduction and a connection point of the first and second diodes, and output of a secondary winding of the high-voltage transformer energizes a magnetron through a high-voltage rectification circuit.

Abstract: An induction heating apparatus can heat aluminum pot etc. with pot vibration noise being suppressed. During a turn-on time of second switching device 57, an energy is accumulated at choke coil 54, and at the same time a resonant current with a shorter period than the turn-on time of second switching device 57 or a driving time of first switching device 55 is generated at heating coil 59, so that during turn-off of second switching device 57, i.e., during on-time of first switching device 55, the energy accumulated at choke coil 54 is transferred to second smoothing capacitor 62. And then the output power is supplied from smoothing capacitor 62 to heating coil 59, thereby reducing the pot vibration noise, which is caused by pulsating current of input voltage.

Abstract: Timing of zero voltage in zero-voltage detector for detecting zero voltage of a commercial power supply 1 is predicted and input from the zero-voltage detector 6 is received only for a given time before and after the predicted timing, whereby overvoltage and overcurrent caused by a zero point shift can be prevented. Thus, it is provided a magnetron drive power supply which is excellent in stability for change in the power supply environment such as noise or instantaneous power interruption.

Abstract: It is provided a magnetron drive power supply wherein a series connection body of first and second semiconductor switch elements that can be brought into reverse conduction and a series connection body of first and second diodes are connected in parallel, first and second capacitors are connected in parallel to the first and second diodes, a series circuit of a commercial power supply and a primary winding of a high-voltage transformer is connected between a connection point of the first and second semiconductor switch elements that can be brought into reverse conduction and a connection point of the first and second diodes, and output of a secondary winding of the high-voltage transformer energizes a magnetron through a high-voltage rectification circuit.

Abstract: A high-frequency inverter having a simple circuit construction capable of executing a constant-frequency operation and a zero-volt switching operation and an induction heating cooker using the high-frequency inverter are disclosed. The high-frequency inverter is comprised of an inverter circuit for converting a direct current from a DC power source into a high-frequency current and a control circuit for controlling the inverter circuit. The inverter circuit is comprised of: a one-transistor inverter constructed of a heating coil whose one terminal is connected to one terminal of a DC power source, a first switching element connected in series between the other terminal of the heating coil and the other terminal of the DC power source, and a first resonance capacitor connected so as to form a resonance circuit with the heating coil; and a series circuit connected in parallel with the heating coil and constructed of a second switching element and a second resonance capacitor.