WO1997030568A1 - Current supply circuit for a magnetron - Google Patents

Current supply circuit for a magnetron Download PDF

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Publication number
WO1997030568A1
WO1997030568A1 PCT/DE1997/000312 DE9700312W WO9730568A1 WO 1997030568 A1 WO1997030568 A1 WO 1997030568A1 DE 9700312 W DE9700312 W DE 9700312W WO 9730568 A1 WO9730568 A1 WO 9730568A1
Authority
WO
WIPO (PCT)
Prior art keywords
power supply
magnetron
voltage
rectifier
supply circuit
Prior art date
Application number
PCT/DE1997/000312
Other languages
German (de)
French (fr)
Inventor
Wolfgang Arnold
Erich Pivit
Thomas Heil
Original Assignee
Advanced Ferrite Technology Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Advanced Ferrite Technology Gmbh filed Critical Advanced Ferrite Technology Gmbh
Publication of WO1997030568A1 publication Critical patent/WO1997030568A1/en

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Classifications

    • 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
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H02M7/10—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode arranged for operation in series, e.g. for multiplication of voltage

Definitions

  • the present invention relates to a power supply circuit for a magnetron.
  • a magnetron is a source for very large high-frequency power. Magnetrons are therefore used to supply high-frequency energy to devices in which objects are to be heated. Such devices include, for example, microwave ovens. Because of the prevailing high field strength, arcing can occur therein. The result of the arcs is that the carriers for the material to be heated, which consist of electrically non-conductive, organic substances, carbonize, which favors further arcing. The material to be heated (e.g. food) burns and is no longer usable. It is therefore necessary to take measures that largely suppress arcing. This can be overcome by the fact that when an arc occurs the output voltage of the magnetron is brought to zero within a very short time ⁇ 100 ⁇ s).
  • the invention is therefore based on the object of specifying a current supply circuit for a magnetron, with which the magnetron can be switched off within a very short time using circuit means which are not very complex.
  • the operating voltage for the magneton is formed from the sum of two direct voltages, a direct voltage being derived from a rectifier circuit from an alternating input voltage and a controllable switching power supply that supplies the other DC voltage from the input AC voltage.
  • the rectifier circuit and the controllable switching power supply are connected in series.
  • the controllable switching power supply acts like a current source, which is why the magnetron provides a stable output power for a microwave device connected to the magnetron.
  • Voltage ripples at the output of the rectifier circuit are compensated for by the series connection of the rectifier circuit and the switching power supply. It is therefore not necessary to connect a filter (L, C network) downstream of the rectifier in order to generate the smoothest possible operating voltage for the magnetron. Ripples in the operating voltage would cause strong current ripples in the magnetron and thus large fluctuations in the output power.
  • the controllable switching power supply enables the magnetron to be switched off very quickly if an arc ignites in the connected microwave device.
  • Figure 2 shows a current / voltage characteristic of a magnetron.
  • FIG. 1 shows a block diagram of a power supply circuit for a magnetron MG which feeds a microwave device ME - for example a microwave oven - with high-frequency energy. All circuit units are as Blocks shown and not detailed, since each is a well-known circuit in itself.
  • a transformer TF generates a first partial AC voltage Ua and a second partial AC voltage U on two separate secondary windings from a 3-phase input AC voltage U on the primary side.
  • the first partial AC voltage Ua is applied to a multi-phase rectifier GI / e.g. 6-phase rectifier), whose DC output voltage Ul has only relatively flat ripples because of the multi-phase rectification.
  • the second partial AC voltage U1 is converted by a rectifier G2 (e.g. 3-phase rectifier) into a DC voltage and then made available to a controllable switching power supply SN.
  • This controllable switched-mode power supply SN is connected in series with the multi-phase rectifier GI.
  • the DC output voltage U1 of the multi-phase rectifier GI and the DC output voltage U2 of the controllable switched-mode power supply SN overlap to form an input voltage U3 for the magnetron MG.
  • the controllable switched-mode power supply SN is set to such an output DC voltage U2 that the ripples of the output DC voltage U1 of the multi-phase rectifier GI are largely compensated for with its ripples.
  • the input voltage UB of the magnetron MG is smoothed, which means that the output power of the magnetron MG which is output to the microwave device ME is subject to only very slight fluctuations. Because of the flat course of the current / voltage characteristic of the Magnetron MG, which is qualitatively shown in FIG. 2, even small ripples in the voltage Um would cause large fluctuations in the current Im and thus in the output power.
  • the output power of the magnetron MG should be brought to zero within a very short time (50-100 ⁇ s). To do this, it is sufficient to reduce the operating voltage ÜB (in normal operation, for example 11-12.5 kV) of the magnetron MG by a partial amount (eg 3 kV). As can be seen from the characteristic curve in FIG. 2 would lead to the magnetron MG being switched off.
  • the controllable switching power supply SN supplies the required partial amount U2 of the operating voltage UB.
  • the switching power supply SN - for example a forward converter - has a control signal input SE.
  • the switched-mode power supply SN sets its DC output voltage U2 to zero within the required short period of time (50-100 ⁇ s), so that it immediately afterwards the magnetron MG is switched off and the arc is extinguished immediately.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)

Abstract

The invention concerns a current supply circuit which is able to deenergize a magnetron (MG) within the shortest time and consists of a rectifier circuit (G1) which produces a first direct voltage component (U1) form an alternating voltage input (U), and a switched-mode power supply (SN) connected in series with the rectifier circuit (G1) which produces a second direct voltage component (U2). The sum of the two direct voltage components (U1, U2) is fed to the magnetron (MG) as the operating voltage (UB).

Description

Stromversorgungsschaltung für ein MagnetronPower supply circuit for a magnetron
Die vorliegende Erfindung betrifft eine Stromversorgungsschal¬ tung für ein Magnetron.The present invention relates to a power supply circuit for a magnetron.
Wie bekannt, ist ein Magnetron eine Quelle für sehr große Hoch¬ frequenzleistung. Deshalb werden Magnetrons eingesetzt, um Ein¬ richtungen, in denen Gegenstände erhitzt werden sollen, mit Hochfrequenzenergie zu versorgen. Zu solchen Einrichtungen gehö¬ ren beispielsweise Mikrowellenherde. Darin kann es wegen der vorherrschenden hohen Feldstärke zur Bildung von Lichtbogen kom¬ men. Die Lichtbogen haben zur Folge, daß die Träger für das zu erhitzende Gut, welche aus elektrisch nichtleitenden, organi¬ schen Substanzen bestehen, verkohlen, wodurch weitere Lichtbo¬ genzündungen begünstigt werden. Das zu erhitzende Gut (z.B. Le¬ bensmittel) verbrennt dabei und ist nicht mehr verwendbar. Es ist daher erforderlich, Maßnahmen zu ergreifen, die Lichtbogen¬ zündungen weitgehend unterdrücken. Dies läßt sich dadurch bewäl¬ tigen, daß bei Auftreten eines Lichtbogens die Ausgangsspannung des Magnetrons innerhalb sehr kurzer Zeit {< 100 μs) auf Null ge¬ bracht wird.As is known, a magnetron is a source for very large high-frequency power. Magnetrons are therefore used to supply high-frequency energy to devices in which objects are to be heated. Such devices include, for example, microwave ovens. Because of the prevailing high field strength, arcing can occur therein. The result of the arcs is that the carriers for the material to be heated, which consist of electrically non-conductive, organic substances, carbonize, which favors further arcing. The material to be heated (e.g. food) burns and is no longer usable. It is therefore necessary to take measures that largely suppress arcing. This can be overcome by the fact that when an arc occurs the output voltage of the magnetron is brought to zero within a very short time {<100 μs).
Der Erfindung liegt daher die Aufgabe zugrunde, eine Stromver¬ sorgungsschaltung für ein Magnetron anzugeben, mit der unter Einsatz wenig aufwendiger Schaltungsmittel das Magnetron inner¬ halb sehr kurzer Zeit abgeschaltet werden kann.The invention is therefore based on the object of specifying a current supply circuit for a magnetron, with which the magnetron can be switched off within a very short time using circuit means which are not very complex.
Erfindungsgemäß wird diese Aufgabe gemäß den Merkmalen des An¬ spruchs 1 dadurch gelöst, daß die Betriebsspannung für das Ma¬ gnetron aus der Summe zweier Gleichspannungen gebildet wird, wo¬ bei eine Gleichspannung von einer Gleichrichterschaltung aus ei¬ ner Eingangs-Wechselspannung abgeleitet wird und ein steuerbares Schaltnetzteil die andere Gleichspannung aus der Eingangs- Wechselspannung liefert. Die Gleichrichterschaltung und das steuerbare Schaltnetzteil sind in Reihe geschaltet. Vorteilhafte Weiterbildungen der Erfindung gehen aus den Un¬ teransprüchen hervor.According to the invention, this object is achieved in accordance with the features of claim 1 in that the operating voltage for the magneton is formed from the sum of two direct voltages, a direct voltage being derived from a rectifier circuit from an alternating input voltage and a controllable switching power supply that supplies the other DC voltage from the input AC voltage. The rectifier circuit and the controllable switching power supply are connected in series. Advantageous developments of the invention emerge from the subclaims.
Das steuerbare Schaltnetzteil wirkt wie eine Stromquelle, wes¬ halb das Magnetron eine stabile Ausgangsleistung für eine an das Magnetron angeschlossene Mikrowellen-Einrichtung zur Verfügung stellt.The controllable switching power supply acts like a current source, which is why the magnetron provides a stable output power for a microwave device connected to the magnetron.
Durch die Reihenschaltung der Gleichrichterschaltung und des Schaltnetzteils werden Spannungsripple am Ausgang der Gleich¬ richterschaltung kompensiert. Es braucht dem Gleichrichter also kein Filter (L-, C-Netzwerk) nachgeschaltet zu werden, um eine möglichst glatte Betriebsspannung für das Magnetron zu erzeugen. Ripple in der Betriebsspannung würden nämlich starke Stromripple im Magnetron und damit starke Schwankungen der Ausgangsleistung hervorrufen.Voltage ripples at the output of the rectifier circuit are compensated for by the series connection of the rectifier circuit and the switching power supply. It is therefore not necessary to connect a filter (L, C network) downstream of the rectifier in order to generate the smoothest possible operating voltage for the magnetron. Ripples in the operating voltage would cause strong current ripples in the magnetron and thus large fluctuations in the output power.
Wegen des durch die Erfindung möglichen Verzichts auf ein L-/C- Filternetzwerks steht auch kein Energielieferant (Kapazität) für schädliche Hochspannungsüberschläge innerhalb und außerhalb des Magnetrons zur Verfügung.Because of the fact that the invention eliminates the need for an L / C filter network, there is also no energy supplier (capacity) available for harmful high voltage flashovers inside and outside the magnetron.
Das steuerbare Schaltnetzteil erlaubt eine sehr schnelle Ab¬ schaltung des Magnetrons, falls in der angeschlossenen Mikrowel¬ len-Einrichtung ein Lichtbogen zündet.The controllable switching power supply enables the magnetron to be switched off very quickly if an arc ignites in the connected microwave device.
Anhand eines in der Zeichnung dargestellten Ausführungsbeispiels wird anschließend die Erfindung näher erläutert.The invention is subsequently explained in more detail using an exemplary embodiment shown in the drawing.
Es zeigen:Show it:
Figur 1 eine Stromversorgungsschaltung für ein Magnetron und1 shows a power supply circuit for a magnetron and
Figur 2 eine Strom-/Spannungs-Kennlinie eines Magnetrons.Figure 2 shows a current / voltage characteristic of a magnetron.
In der Figur 1 ist ein Blockschaltbild einer Stromversorgungs- schaltung für ein Magnetron MG dargestellt, das eine Mikrowel¬ len-Einrichtung ME - beispielsweise einen Mikrowellenherd - mit Hochfrequenzenergie speist. Alle Schaltungseinheiten sind als Blöcke dargestellt und nicht im Detail ausgeführt, da jede für sich eine allgemein bekannte Schaltung ist .FIG. 1 shows a block diagram of a power supply circuit for a magnetron MG which feeds a microwave device ME - for example a microwave oven - with high-frequency energy. All circuit units are as Blocks shown and not detailed, since each is a well-known circuit in itself.
Ein Transformator TF erzeugt an zwei getrennten Sekundärwicklun¬ gen aus einer primarseitig anliegenden 3-Phasen Eingangs- Wechselspannung U eine erste Teil-Wechselspannung Ua und eine zweite Teil-Wechselspannung Üb. Die erste Teil-Wechselspannung Ua wird einem Mehrphasen-Gleichrichter GI /z.B. 6-Phasen- Gleichrichter) zugeführt, dessen Ausgangs-Gleichspannung Ul we¬ gen der mehrphasigen Gleichrichtung nur relativ flache Ripple aufweist. Die zweite Teil-Wechselspannung Üb wird von einem Gleichrichter G2 (z.B. 3-Phasen-Gleichrichter) in eine Gleich¬ spannung umgeformt und dann einem steuerbaren Schaltnetzteil SN bereitgestellt. Diese steuerbare Schaltnetzteil SN ist mit dem Mehrphasen-Gleichrichter GI in Reihe geschaltet. Somit überla¬ gern sich die Ausgang-Gleichspannung Ul des Mehrphasen- Gleichrichters GI und die Ausgangs-Gleichspannung U2 des steuer¬ baren Schaltnetzteils SN zu einer Eingangs-Spannung U3 für das Magnetron MG. Das steuerbare Schaltnetzteil SN wird auf eine solche Ausgangs-Gleichspannung U2 eingestellt, daß diese mit ih¬ ren Ripples die Ripples der Ausgangs-Gleichspannung Ul des Mehr¬ phasen-Gleichrichters GI möglichst weitgehend kompensiert. Da¬ durch erhält die Eingangs-Spannung ÜB des Magnetrons MG einen geglätteten Verlauf, was dazu führt, daß die an die Mikrowellen- Einrichtung ME abgegebene Ausgangsleistung des Magnetrons MG nur sehr geringen Schwankungen unterliegt. Denn wegen des in Figur 2 qualitativ dargestellten flachen Verlaufs der Strom- /Spannungskennlinie des Magnetron MG würden schon kleine Ripple der Spannung Um große Schwankungen des Stromes Im und damit der Ausgangsleistung hervorrufen.A transformer TF generates a first partial AC voltage Ua and a second partial AC voltage U on two separate secondary windings from a 3-phase input AC voltage U on the primary side. The first partial AC voltage Ua is applied to a multi-phase rectifier GI / e.g. 6-phase rectifier), whose DC output voltage Ul has only relatively flat ripples because of the multi-phase rectification. The second partial AC voltage U1 is converted by a rectifier G2 (e.g. 3-phase rectifier) into a DC voltage and then made available to a controllable switching power supply SN. This controllable switched-mode power supply SN is connected in series with the multi-phase rectifier GI. Thus, the DC output voltage U1 of the multi-phase rectifier GI and the DC output voltage U2 of the controllable switched-mode power supply SN overlap to form an input voltage U3 for the magnetron MG. The controllable switched-mode power supply SN is set to such an output DC voltage U2 that the ripples of the output DC voltage U1 of the multi-phase rectifier GI are largely compensated for with its ripples. As a result, the input voltage UB of the magnetron MG is smoothed, which means that the output power of the magnetron MG which is output to the microwave device ME is subject to only very slight fluctuations. Because of the flat course of the current / voltage characteristic of the Magnetron MG, which is qualitatively shown in FIG. 2, even small ripples in the voltage Um would cause large fluctuations in the current Im and thus in the output power.
Im Falle eines Lichtbogen-Überschlages in der Mikrowellen- Einrichtung ME sollte die Ausgangsleistung des Magnetrons MG in¬ nerhalb kürzester Zeit (50-100 μs) auf Null gefahren werden. Dazu reicht es aus, die Betriebsspannung ÜB (im Normalbetrieb z.B. 11-12,5 kV) des Magnetrons MG um einen Teilbetrag (Z.B. 3 kV) zu reduzieren. Wie dem Kennlinienverlauf der Figur 2 zu entnehmen ist, würde des zu einem Abschalten des Magnetrons MG führen. Den erforderlichen Teilbetrag U2 der Betriebsspannung ÜB liefert ge¬ rade das steuerbare Schaltnetzteil SN. Das Schaltnetzteil SN - beispielsweise ein Durchflußwandler - besitzt einen Steuersi¬ gnaleingang SE. Liegt an diesem Steuersignaleingang SE ein Steu¬ ersignal an, welches das Entstehen eines Lichtbogens in der Mikrowellen-Einrichtung ME anzeigt, setzt das Schaltnetzteil SN seine Ausgangs-Gleichspannung U2 innerhalb der erforderlichen kurzen Zeitspanne (50-100 μs) auf Null, so daß es unmittelbar darauf zu einem Abschalten des Magnetrons MG kommt und der Lichtbogen sofort gelöscht wird. In the event of an arcing in the microwave device ME, the output power of the magnetron MG should be brought to zero within a very short time (50-100 μs). To do this, it is sufficient to reduce the operating voltage ÜB (in normal operation, for example 11-12.5 kV) of the magnetron MG by a partial amount (eg 3 kV). As can be seen from the characteristic curve in FIG. 2 would lead to the magnetron MG being switched off. The controllable switching power supply SN supplies the required partial amount U2 of the operating voltage UB. The switching power supply SN - for example a forward converter - has a control signal input SE. If a control signal is present at this control signal input SE, which indicates the occurrence of an arc in the microwave device ME, the switched-mode power supply SN sets its DC output voltage U2 to zero within the required short period of time (50-100 μs), so that it immediately afterwards the magnetron MG is switched off and the arc is extinguished immediately.

Claims

Patentansprüche claims
1. Stromversorgungsschaltung für ein Magnetron, dadurch gekenn¬ zeichnet, daß die Betriebsspannung (ÜB) für das Magnetron (MG) aus der Summe zweier Gleichspannungen (Ul, U2) resultiert, daß eine Gleichrichterschaltung (GI) aus einem ersten Anteil (Ua) einer Eingangs-Wechselspannung (Ul) eine der beiden Gleichspan¬ nungen (Ul, U2) erzeugt und daß ein steuerbares Schaltnetzteil (SN) , welches mit der Gleichrichterschaltung (GI) in Reihe ge¬ schaltet ist, aus einem zweiten Anteil (Üb) der Eingangs- Wechselspannung (U) die zweite Gleichspannung (U2) erzeugt.1. Power supply circuit for a magnetron, characterized gekenn¬ characterized in that the operating voltage (ÜB) for the magnetron (MG) results from the sum of two DC voltages (Ul, U2) that a rectifier circuit (GI) from a first portion (Ua) one AC input voltage (U1) generates one of the two DC voltages (U1, U2) and that a controllable switched-mode power supply (SN), which is connected in series with the rectifier circuit (GI), consists of a second portion (Ub) of the input - AC voltage (U) generates the second DC voltage (U2).
2. Stromversorgungsschaltung nach Anspruch 1, dadurch gekenn¬ zeichnet, daß die Gleichrichterschaltung (GI) eine Mehrphasen- Gleichrichter ist.2. Power supply circuit according to claim 1, characterized gekenn¬ characterized in that the rectifier circuit (GI) is a multi-phase rectifier.
3. Stromversorgungsschaltung nach Anspruch 1, dadurch gekenn¬ zeichnet, daß dem Schaltnetzteil (SN) ein Gleichrichter (G2) vorgeschaltet ist.3. Power supply circuit according to claim 1, characterized gekenn¬ characterized in that the switching power supply (SN), a rectifier (G2) is connected upstream.
4. Stromversorgungsschaltung nach Anspruch 1, dadurch gekenn¬ zeichnet, daß ein Transformator (TF) die Eingangs- Wechselspannung (U) durch getrennte Wicklungen auf seiner Sekun¬ därseite in die zwei Teil-Spannungen (Ua, Üb) für die Gleich¬ richterschaltung (GI) und das steuerbare Schaltnetzteil (SN) aufteilt .4. Power supply circuit according to claim 1, characterized gekenn¬ characterized in that a transformer (TF) the input AC voltage (U) by separate windings on its secondary side in the two partial voltages (Ua, Ü) for the rectifier circuit ( GI) and the controllable switching power supply (SN) divides.
5. Stromversorgungsschaltung nach Anspruch 1, dadurch gekenn¬ zeichnet, daß das steuerbare Schaltnetzteil (SN) einen Eingang (SE) für ein Steuersignal aufweist, welches bei Entstehung eines Lichtbogens in einer von dem Magnetron (MG) mit Hochfrequenz- energie versorgten Einrichtung (SN) - vorzugsweise eines Mikro¬ wellenherdes - das Schaltnetzteil abschaltet. 5. Power supply circuit according to claim 1, characterized gekenn¬ characterized in that the controllable switching power supply (SN) has an input (SE) for a control signal, which in the event of an arc in one of the magnetron (MG) with high frequency Energy-supplied device (SN) - preferably a microwave oven - switches off the switching power supply.
PCT/DE1997/000312 1996-02-19 1997-02-13 Current supply circuit for a magnetron WO1997030568A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1996106049 DE19606049C1 (en) 1996-02-19 1996-02-19 Magnetron current supply circuit e.g. for microwave oven
DE19606049.4 1996-02-19

Publications (1)

Publication Number Publication Date
WO1997030568A1 true WO1997030568A1 (en) 1997-08-21

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Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3019841B1 (en) * 1998-09-30 2000-03-13 日本電気株式会社 High voltage power supply circuit

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3702969A (en) * 1970-09-18 1972-11-14 Int Standard Electric Corp Power supply circuit for continuous-wave magnetron
DE2950359A1 (en) * 1979-12-14 1981-06-19 Hans Dr.rer.nat. Beerwald HV power supply for power magnetron - has uncontrolled HV supply circuit and controlled LV supply circuits in series at outputs
DE3437064A1 (en) * 1984-10-09 1986-04-10 Siemens AG, 1000 Berlin und 8000 München Medium-frequency X-ray generator
DE3700495A1 (en) * 1982-05-14 1988-07-28 Dassault Electronique SUPPLY DEVICE FOR A WAVE GENERATOR FOR AN IMPULSE RADAR
US5270509A (en) * 1991-12-24 1993-12-14 Electric Power Research Institute Microwave clothes drying system and method with improved arc detection
US5424515A (en) * 1992-04-06 1995-06-13 Micro Dry Inc. Method and apparatus for the prevention of scorching of fabric subjected to microwave heating

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR910001986B1 (en) * 1987-04-30 1991-03-30 마쯔시다덴기산교 가부시기가이샤 Magnetron feeding apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3702969A (en) * 1970-09-18 1972-11-14 Int Standard Electric Corp Power supply circuit for continuous-wave magnetron
DE2950359A1 (en) * 1979-12-14 1981-06-19 Hans Dr.rer.nat. Beerwald HV power supply for power magnetron - has uncontrolled HV supply circuit and controlled LV supply circuits in series at outputs
DE3700495A1 (en) * 1982-05-14 1988-07-28 Dassault Electronique SUPPLY DEVICE FOR A WAVE GENERATOR FOR AN IMPULSE RADAR
DE3437064A1 (en) * 1984-10-09 1986-04-10 Siemens AG, 1000 Berlin und 8000 München Medium-frequency X-ray generator
US5270509A (en) * 1991-12-24 1993-12-14 Electric Power Research Institute Microwave clothes drying system and method with improved arc detection
US5424515A (en) * 1992-04-06 1995-06-13 Micro Dry Inc. Method and apparatus for the prevention of scorching of fabric subjected to microwave heating

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