Magnetron drive power supply

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, output of a secondary winding of the high-voltage transformer energizes a magnetron through a high-voltage rectification circuit, and a drive circuit for driving the first and second semiconductor switch elements is provided and drives the first and second semiconductor switch elements complementarily and replaces drive signals depending on whether the commercial power supply is of positive or negative polarity.

A high-frequency heating power supply unit 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, output of a secondary winding of the high-voltage transformer drives a magnetron through a high-voltage rectification circuit, and each of on-off duty ratios of the first and second semiconductor switch elements that can be brought into reverse conduction is set to about 50% in the vicinity of a polarity change point where the polarity of the commercial power supply changes.

A high-frequency heating power supply unit 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, output of a secondary winding of the high-voltage transformer drives a magnetron through a high-voltage rectification circuit, and while polarity determination means is provided in control of the vicinity of a polarity change point of the commercial power supply, the polarity change point is detected, whereby roles of the first and second semiconductor switch elements that can be brought into reverse conduction for playing a role of both a step-up charging-up function and an inverter function and a role of only the inverter function complementarily at the same time are replaced.

A magnetron drive power supply comprising a series connection body of first and second semiconductor switches, first and second fly-wheel diodes in inverse parallel to the first and second semiconductor switches, a series connection body of first and second rectification diodes connected in parallel to the first and second semiconductor switches, first and second capacitors connected in parallel to the first and second rectification diodes, a commercial power supply and a primary winding of a high-voltage transformer connected in series to each other, connected between a connection point of the first and second semiconductor switches and a connection point of the first and second rectification diodes, and a high-voltage rectification circuit and a magnetron connected to output of a secondary winding of the high-voltage transformer, characterized in that the first and second fly-wheel diodes and the first and second rectification diodes are housed in one package.