US3671847A - Power supply for driving magnetron - Google Patents

Power supply for driving magnetron Download PDF

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Publication number
US3671847A
US3671847A US67961A US3671847DA US3671847A US 3671847 A US3671847 A US 3671847A US 67961 A US67961 A US 67961A US 3671847D A US3671847D A US 3671847DA US 3671847 A US3671847 A US 3671847A
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United States
Prior art keywords
winding
core
halves
magnetron
wound
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Expired - Lifetime
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US67961A
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English (en)
Inventor
Takashi Shibano
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/66—Circuits
    • H05B6/666—Safety circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B9/00—Generation of oscillations using transit-time effects
    • H03B9/01—Generation of oscillations using transit-time effects using discharge tubes
    • H03B9/10—Generation of oscillations using transit-time effects using discharge tubes using a magnetron
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/66—Circuits
    • H05B6/68—Circuits for monitoring or control
    • H05B6/687—Circuits for monitoring or control for cooking
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F2038/003—High frequency transformer for microwave oven

Definitions

  • ABSTRACT [30] Foreign Application Priority Data A compact power supply for driving a magnetron to oscillation used for an electronic cooking range.
  • a transformer hav- March 20, 1970 Japan ..44/27165 ing a threeJessed magnetic core with at least primary. Secon dary and tertiary windings. The primary winding is divided [52] U.S.
  • FIG. 2 is a schematic diagram of the main transformer used in the power supply shown in FIG. 1;
  • FIGS. 3 to 6 are connection diagrams of different embodiments of the device of this invention.
  • FIGS. 11 to 14 are schematic diagrams showing the operation of the transformers.
  • the secondary high voltage circuit is controlled simply by a switching operation of the magnetic contactor, while the heater circuit is maintained alive. Further, this invention provides an additional advantage that if the door of the oven is opened during the operation, the magnetron oscillator is stopped with high reliability, thus assuredly preventing leakage of the harmful high frequency wave.
  • the power supply for a magnetron oscillator of this invention comprises a transformer which has a three-legged magnetic core, a pair of halves of the primary winding, each of the pair being wound on each of the outer legs of the core, a secondary winding wound on the center leg of the core for providing the magnetron with a high voltage and a third winding wound on cathode of the magnetron with heating power, and switching means connected with said halves of the primary winding so as to be able to change the direction of the magnetic flux produced by one of said half primary windings in relation to that by the other half primary winding while said halves of the primary winding are connected in parallel.
  • indexes (1: d1 designate leakage fluxes which are produced when the load current flows through the secondary winding 102. It will be seen from FIGSQll and 12 that a voltage of substantially constant amplitude is induced in the third coil 103 by the flux regardless of the switched position of the contacts MS. Therefore, the heater of the magnetron cathode is kept energized regardless of the manner of connection of two half primary windings. In other words, the magnetron can be driven to oscillation or brought to rest, while the cathode is kept heated by a substantially constant power.
  • a voltage is induced in the third winding 103 to allow a current to flow through the cathode heater of the magnetron.
  • This heating current produces the magnetic flux 135,, in the direction opposite to that of the flux the said flux dz in turn inducing a counter flux 4 which is maintained by an additional current in the winding 101.
  • a flux da corresponding to d) is produced by the winding 101 and it flows through the center leg of the core. Therefore, the total flux in the center leg mounts to 11:, 41, d) z (b, 4;, da
  • a high voltage sufficient to drive the magnetron is induced in the secondary winding 102.
  • the load current Upon the energization of the magnetron, the load current produces fluxes and 1b which flow through the leakage paths 106.
  • the third winding 103 always produces a voltage of a substantially constant amplitude regardless of the position of the contacts. Therefore, the magnetron can be driven or stopped, while the cathode is kept heated.
  • the fourth winding may not necessarily be a separate winding but may be provided as a part or an extension of the secondary winding.
  • FIG. 5 shows a further embodiment of this invention.
  • the structure and the operation of the trans former are similar to those described in connection with FIG. 4.
  • a special feature of this embodiment is the fact that door switches which are interlocked with the oven door are connected in series with the normally-open contacts of the magnetic contactor. With this arrangement, it is ensured that the oscillation of the magnetron stops if the oven door is opened during the operation, thereby preventing the radiation of the high frequency wave out of the oven. It will be clear that a similar effect is obtained with a single door switch connected with either one of the nonnally-open contacts. Further, if an additional door switch is connected in series with the magnetic coil MSC of the magnetic contactor, the interlocked stoppage of the oscillation is still more assured, as the contacts MS are switched so as to nullify the secondary voltage.
  • a power supply for a magnetron oscillator comprising a transformer which has a three-legged magnetic core, a primary winding divided into halves, each half being wound on one of the outer legs of the core, a secondary winding divided into halves, each half being wound on one of the outer legs of the core, said halves of the secondary winding being connected in series, the secondary winding providing the magnetron with high voltage, and a third winding wound on either one of the outer legs of the core for providing the cathode of the magnetron with heating power; and switching means connected with said halves of the primary winding to change the direction of the magnetic flux produced by one of said half primary windings in relation to that produced by the other half primary winding while said halves of the primary winding are connected in parallel so that said third winding can be always energized to produce a constant output power irrespective of energization or de-energization of said secondary winding.
  • a power supply for a magnetron oscillator comprising a transformer which has a three-legged magnetic core, a magnetic bypath being provided between the center leg and each outer leg dividing the center leg of said transformer into two equal sections, a primary winding divided into halves, each half being wound on each of the two sections of the center leg of the core, a secondary winding divided into halves, each half being wound on one of the two sections of the center leg of the core, said halves of the secondary winding being connected in series, the secondary winding providing the magnetron with high voltage, and a third winding wound on either one of the two sections of the center leg of the core for providing the cathode of the magnetron with heating power; and switching means connected with said halves of the primary winding to change the direction of the magnetic flux produced by one of said half primary windings in relation to that produced by the other half primary winding while said halves of the primary winding are connected in parallel so that said third winding can be always energized to produce a constant output power irrespective of
  • a power supply for a magnetron oscillator comprising a transformer which has a three-legged magnetic core, a pair of halves of the primary winding, each of the pair being wound on each of the outer legs of the core, a secondary winding wound on the center leg of the core for providing the magnetron with a high voltage, a third winding wound on either one of the outer legs of the core for providing the cathode of the magnetron with a heating power, and a fourth winding wound on the center leg of the core; a first switching means connected with said halves of primary winding so as to be able to change the direction of the magnetic flux produced by one of said half primary windings in relation to that by the other half primary winding while said halves of primary winding are connected in series; and a second switching means connected across the terminals of the fourth winding, said second switching means being so interlocked with said first switching means that when the fluxes due to said half primary windings cancel each other in the center leg of the core, the fourth winding is closed,

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
US67961A 1970-03-20 1970-08-28 Power supply for driving magnetron Expired - Lifetime US3671847A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1970027165U JPS5122569Y1 (enrdf_load_stackoverflow) 1970-03-20 1970-03-20

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US3671847A true US3671847A (en) 1972-06-20

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JP (1) JPS5122569Y1 (enrdf_load_stackoverflow)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3867605A (en) * 1973-08-06 1975-02-18 Welbuilt Corp Microwave oven
US4142082A (en) * 1975-12-18 1979-02-27 Raytheon Company High frequency power supply microwave oven
FR2641661A2 (fr) * 1984-12-24 1990-07-13 Jakoubovitch Albert Perfectionnement au generateur aperiodique
EP0352834A3 (fr) * 1988-07-25 1992-06-17 Albert Jakoubovitch Perfectionnement au générateur apériodique
US20090231081A1 (en) * 2008-03-14 2009-09-17 Alexandr Ikriannikov Voltage Converter Inductor Having A Nonlinear Inductance Value
US8836461B2 (en) 2002-12-13 2014-09-16 Volterra Semiconductor Corporation Method for making magnetic components with M-phase coupling, and related inductor structures
US9019063B2 (en) 2009-08-10 2015-04-28 Volterra Semiconductor Corporation Coupled inductor with improved leakage inductance control
US9281115B2 (en) 2009-12-21 2016-03-08 Volterra Semiconductor LLC Multi-turn inductors
US9287038B2 (en) 2013-03-13 2016-03-15 Volterra Semiconductor LLC Coupled inductors with non-uniform winding terminal distributions
US9336941B1 (en) 2013-10-30 2016-05-10 Volterra Semiconductor LLC Multi-row coupled inductors and associated systems and methods
US9691538B1 (en) 2012-08-30 2017-06-27 Volterra Semiconductor LLC Magnetic devices for power converters with light load enhancers
US9767947B1 (en) 2011-03-02 2017-09-19 Volterra Semiconductor LLC Coupled inductors enabling increased switching stage pitch
US11476031B1 (en) * 2018-08-01 2022-10-18 Smart Wires Inc. Current adaptive reactor structure

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB347538A (en) * 1929-06-29 1931-04-30 Gen Electric Improvements in and relating to regulating means for electric transformers
US2543887A (en) * 1947-03-11 1951-03-06 Raytheon Mfg Co Magnetron power supply circuits
US2648772A (en) * 1949-02-15 1953-08-11 Raytheon Mfg Co Magnetron control circuits
US2686291A (en) * 1950-03-13 1954-08-10 Servo Corp Variable reluctance control means
US3289000A (en) * 1965-02-23 1966-11-29 Automation Ind Inc Means for separately controlling the filament current and voltage on an X-ray tube
US3351808A (en) * 1963-08-28 1967-11-07 Siemens Ag Albis Feed current control for pulse-modulated magnetron transmitter

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB347538A (en) * 1929-06-29 1931-04-30 Gen Electric Improvements in and relating to regulating means for electric transformers
US2543887A (en) * 1947-03-11 1951-03-06 Raytheon Mfg Co Magnetron power supply circuits
US2648772A (en) * 1949-02-15 1953-08-11 Raytheon Mfg Co Magnetron control circuits
US2686291A (en) * 1950-03-13 1954-08-10 Servo Corp Variable reluctance control means
US3351808A (en) * 1963-08-28 1967-11-07 Siemens Ag Albis Feed current control for pulse-modulated magnetron transmitter
US3289000A (en) * 1965-02-23 1966-11-29 Automation Ind Inc Means for separately controlling the filament current and voltage on an X-ray tube

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3867605A (en) * 1973-08-06 1975-02-18 Welbuilt Corp Microwave oven
US4142082A (en) * 1975-12-18 1979-02-27 Raytheon Company High frequency power supply microwave oven
FR2641661A2 (fr) * 1984-12-24 1990-07-13 Jakoubovitch Albert Perfectionnement au generateur aperiodique
EP0352834A3 (fr) * 1988-07-25 1992-06-17 Albert Jakoubovitch Perfectionnement au générateur apériodique
US8836461B2 (en) 2002-12-13 2014-09-16 Volterra Semiconductor Corporation Method for making magnetic components with M-phase coupling, and related inductor structures
US9147515B2 (en) 2002-12-13 2015-09-29 Volterra Semiconductor LLC Method for making magnetic components with M-phase coupling, and related inductor structures
US9627125B2 (en) 2008-03-14 2017-04-18 Volterra Semiconductor LLC Voltage converter inductor having a nonlinear inductance value
US20090231081A1 (en) * 2008-03-14 2009-09-17 Alexandr Ikriannikov Voltage Converter Inductor Having A Nonlinear Inductance Value
US8836463B2 (en) * 2008-03-14 2014-09-16 Volterra Semiconductor Corporation Voltage converter inductor having a nonlinear inductance value
US9019063B2 (en) 2009-08-10 2015-04-28 Volterra Semiconductor Corporation Coupled inductor with improved leakage inductance control
US9281115B2 (en) 2009-12-21 2016-03-08 Volterra Semiconductor LLC Multi-turn inductors
US9767947B1 (en) 2011-03-02 2017-09-19 Volterra Semiconductor LLC Coupled inductors enabling increased switching stage pitch
US9691538B1 (en) 2012-08-30 2017-06-27 Volterra Semiconductor LLC Magnetic devices for power converters with light load enhancers
US11062830B1 (en) 2012-08-30 2021-07-13 Volterra Semiconductor LLC Magnetic devices for power converters with light load enhancers
US11862389B1 (en) 2012-08-30 2024-01-02 Volterra Semiconductor LLC Magnetic devices for power converters with light load enhancers
US9704629B2 (en) 2013-03-13 2017-07-11 Volterra Semiconductor LLC Coupled inductors with non-uniform winding terminal distributions
US9287038B2 (en) 2013-03-13 2016-03-15 Volterra Semiconductor LLC Coupled inductors with non-uniform winding terminal distributions
US10276288B2 (en) 2013-03-13 2019-04-30 Volterra Semiconductor LLC Coupled inductors with non-uniform winding terminal distributions
US9336941B1 (en) 2013-10-30 2016-05-10 Volterra Semiconductor LLC Multi-row coupled inductors and associated systems and methods
US11476031B1 (en) * 2018-08-01 2022-10-18 Smart Wires Inc. Current adaptive reactor structure

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Publication number Publication date
JPS5122569Y1 (enrdf_load_stackoverflow) 1976-06-11

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