EP0054445A1 - Electronic induction heating arrangememt - Google Patents

Electronic induction heating arrangememt Download PDF

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Publication number
EP0054445A1
EP0054445A1 EP81401726A EP81401726A EP0054445A1 EP 0054445 A1 EP0054445 A1 EP 0054445A1 EP 81401726 A EP81401726 A EP 81401726A EP 81401726 A EP81401726 A EP 81401726A EP 0054445 A1 EP0054445 A1 EP 0054445A1
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EP
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Prior art keywords
oscillating circuit
switches
circuit
electronic
tyristors
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EP81401726A
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German (de)
French (fr)
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EP0054445B1 (en
Inventor
Maurice Scholtes
Roger Eisenberg
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Eugene Scholtes SA
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Eugene Scholtes SA
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Priority to AT81401726T priority Critical patent/ATE15576T1/en
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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
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power

Definitions

  • the present invention relates to electronic devices: induction heating.
  • the object of the present invention is therefore. to eliminate one of these three conditions, in this case that relating to the fact of being able to withstand a repetitive maximum voltage in the blocked state, so as to produce an induction heating device, the design of which is such that it has a very high reliability, despite the performance limits of electronic components currently on the market.
  • this device is characterized in that its oscillating circuit, which comprises a capacitor and a choke in parallel, is connected to the supply circuit by two electronic switches - for example two tyristors - subject to a control circuit making them switch together, so that, when these two switches close, the oscillating circuit is referenced between these two supply lines and, thereby, loaded with energy.
  • oscillating circuit which comprises a capacitor and a choke in parallel
  • the oscillating circuit 1 of the corresponding device is constituted by a circuit known under the name "plug circuit".
  • This includes a plane inductor 2 mounted in parallel with a capacitor 3, the values of which are such that the circuit resonates at the desired frequency, for example 25'k.Hertz in the above-mentioned case of a household appliance.
  • the inductor 2 then acts as the primary winding, the secondary being constituted by the charge to be heated, in the corresponding appliance, in this case a cooking utensil (saucepan, frying pan, etc.).
  • the oscillating circuit 1 is connected to the two lines 5 and 6 of the supply circuit by means of two electronic switches, which are therefore located on either side of this oscillating circuit.
  • each of these switches consists of a tyristor 7 with which is mounted in anti-parallel a diode 8 whose direction of conduction is therefore opposite.
  • each of the tyristors 7 is connected to a very simplified control circuit in the example and designated by the general reference.
  • the arrangement of this circuit is such that the tyristors operate at the resamance frequency of the oscillating circuit 1 in opening and closing at the same time.
  • This circuit includes a. astable type 10 control oscillator, tracking. one, or even several, transiston (s) making it possible to obtain control pulses compatible in duration, in polarity and in power to correctly control the switches, of power.
  • the plug circuit is perfectly adequate to fulfill this additional role. Indeed, the phenomena of overvoltage of such circuits feels well known.
  • This inductor can be formed in different ways, for example on air, on a nucleus of different shapes, or more simply by passing the power wire of the oscillating circuit through a toroid of good value.
  • This small choke has the effect of slowing down or rather delaying the action of the heating choke 2, which results in a induction time of the tyristors of the order of 10 ⁇ seconds in the example.
  • the oscillating circuit is charged with energy through the two power tyristors 7.
  • the plug circuit is then normally referenced between lines 5 and 6 of the supply circuit.
  • the oscillating circuit (comparable in this phase to an energy generator) will, for reference, find at its terminals the open switches 7. The latter therefore serve as a reference for the oscillating circuit, which has the effect of trying to center the voltages across the terminals of this circuit between two very large impedances.
  • each switch supports at its terminals the half of the voltage developed by the oscillating circuit, ie 300 volts in the example.
  • this-tensicn is of the order of 600 to 700 volts instead of 800 to 900 volts.
  • the particular design of the device according to the invention therefore greatly multiplies the safety coefficients, since the voltages at the terminals of the switches are divided by two.
  • this design has the advantage of eliminating the usual drawbacks of electronic induction heating devices, including the risks of thermal runaway of the active components (power switch). Indeed, in this case, a switch effectively protects the other, knowing that the components are never perfectly identical, and moreover, never exposed to the same temperatures.
  • the main advantage of the device according to the invention lies in the fact that, for the same voltage of the oscillating circuit, the voltage safety margin of the electronic switches is considerably increased.
  • the device according to the invention is not limited to the single preferred example described above.
  • the oscillating circuit of this device can be produced differently.
  • the power tyristors could be replaced by power transistors, with a few touch-ups inherent in the equipment used.
  • FIG. 3 represents the diagram of an embodiment in which the tyristors 7 of the previous example are replaced by transistors 7a.
  • the present device is not limited to the production of cooking appliances for household use, since it can be the subject of various applications.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Induction Heating (AREA)
  • Near-Field Transmission Systems (AREA)
  • Steam Or Hot-Water Central Heating Systems (AREA)
  • Air-Conditioning For Vehicles (AREA)
  • Inverter Devices (AREA)

Abstract

1. Electronic induction heating device comprising an oscillating circuit made up of a capacitor and an inductance coil which performs the function of a primary winding, the secondary winding being constituted by the charge to be heated, this oscillating circuit being connected to the supply circuit via two electronic switches associated with a control circuit, a resistor and a capacitor being mounted in parallel with each of these switches, characterized in that the two electronic switches - for example two thyristors (7) - are associated with a control oscillator (10) which causes them to operate at the resonance frequency of the oscillating circuit (2-3) so as to open and close at the same time, these switches being designed to perform the function of impedances of very high value at the time of opening.

Description

La présente invention concerne les dispositifs électroniques: de chauffage à induction.The present invention relates to electronic devices: induction heating.

Les composants de puissance de tels dispositifs doivent répondre à des critères d'intensité, de vitesse= et de tension relativement severes, ce qui les rend pen couldits et de prin eleve.The power components of such devices must meet relatively severe criteria of intensity, speed = and tension, which makes them pen couldits and prin high.

En effet, pour satisfaire aux besoins, par exemple dans le cas d'un appareil de cuisson à induction à vocation ménagère, il faut que; ces composants soient :

  • a) suffisamment rapides en comnutation pour pouvoir fermer et ouvrir un circuit oscillant â des fréquences de l'ordre de 20 à 40 kHz
  • b) capables de supporter des intensités élevées, de l'ordre de 40 ampères. en régime permanent (pour une puissance de 2kW induite)
  • c) susceptibles de supporter, à leurs bornes, des. tensions très élevées de l'ordre de 1000 wolts compte-tenu qu'un circuit résonnant pour un appareil de cuisson à usage ménager développe des tensions de l'ordre de 800 à 900 volts pour un foyer de 2kW alimenté par un réseau de 220 volts.
Indeed, to meet the needs, for example in the case of an induction cooking appliance for household use, it is necessary that; these components are:
  • a) fast enough in switching to be able to close and open an oscillating circuit at frequencies of the order of 20 to 40 kHz
  • b) capable of withstanding high intensities, of the order of 40 amps. in steady state (for an induced power of 2kW)
  • c) likely to bear, at their terminals,. very high voltages of the order of 1000 wolts given that a resonant circuit for a cooking appliance for household use develops voltages of the order of 800 to 900 volts for a 2kW hearth supplied by a 220 volt network .

Or, ces trois conditions sont difficiles à respecter ensemble.These three conditions are difficult to meet together.

Il est par contre-beaucoup plus aisé de trouver sur le marché actuel des composants répondant à deux de ces conditions.On the other hand, it is much easier to find components on the current market that meet two of these conditions.

Le but de la présente invention est donc. d'éliminer l'une de ces trois conditions, en l'occurrence celle relative au fait de pouvoir supporter une tension maximum répétitive à l'état bloqué et ce, de façon à réaliser un dispositif de chauffage à induction, dont la conception est telle que celui-ci présente une très grande fiabilité, malgré les limites de performances des composants électroniques actuellement sur le marché.The object of the present invention is therefore. to eliminate one of these three conditions, in this case that relating to the fact of being able to withstand a repetitive maximum voltage in the blocked state, so as to produce an induction heating device, the design of which is such that it has a very high reliability, despite the performance limits of electronic components currently on the market.

A cet effet, ce dispositif est caractérisé en ce que son circuit oscillant, qui comprend un condensateur et une self en parallèle, est raccordé au circuit d'alimentation par deux interrupteurs électroniques - par exemple deux tyristors - assujettis à un circuit de commande les faisant commuter ensemble, de manière à ce que, lorsque ces deux interrupteurs se ferment, le circuit oscillant se trouve référencé entre ces deux lignes d'alimentation et, par le fait, chargé en énergie.To this end, this device is characterized in that its oscillating circuit, which comprises a capacitor and a choke in parallel, is connected to the supply circuit by two electronic switches - for example two tyristors - subject to a control circuit making them switch together, so that, when these two switches close, the oscillating circuit is referenced between these two supply lines and, thereby, loaded with energy.

Par contre, lorsque les deux interrupteurs sent ouverts, le circuit oscillant, chargé en énergie (et. conparable dans cette phase à un génératour),va trauver à ges bomes deux interrupteurs ouverts, et par suite, se référencer à travers deux très grandes impédances. Ceci aura pour effet que ce circuit aura tendance à se centrer, ou à trouver son équilibre, entre ces deux impédances de grande valeur.On the other hand, when the two switches feel open, the oscillating circuit, charged with energy (and comparable in this phase to a generatour), will find two open switches ges bomes, and consequently, reference itself through two very large impedances . This will have the effect that this circuit will tend to center, or find its equilibrium, between these two impedances of great value.

Du reste, les particularités et avantages du présent dispositif apparaîtront plus clairement au cours de la description suivante, donnée en référence aux dessins annexés.Moreover, the features and advantages of the present device will appear more clearly during the following description, given with reference to the accompanying drawings.

Sur ceux-ci :

  • La figure 1 est un schéma général d'une forme préférentielle de réalisation du dispositif selon l'invention ;
  • La figure 2 représente les courbes de variation des tensions aux bornes des deux interrupteurs électroniques, ainsi que la courbe de variation de l'intensité dans la self du circuit oscillant ;
  • La figure 3 est un schéma général d'une autre forme de réalisation du dispositif selon l'invention.
On these:
  • Figure 1 is a general diagram of a preferred embodiment of the device according to the invention;
  • FIG. 2 represents the curves of variation of the voltages at the terminals of the two electronic switches, as well as the curve of variation of the intensity in the inductor of the oscillating circuit;
  • Figure 3 is a general diagram of another embodiment of the device according to the invention.

Dans l'exemple illustré à la figure 1, le circuit oscillant 1 du dispositif correspondant est constitué par un circuit connu sous l'appellation "circuit bouchon".In the example illustrated in FIG. 1, the oscillating circuit 1 of the corresponding device is constituted by a circuit known under the name "plug circuit".

Celui-ci comprend une self plane 2 montée en parallèle avec un condensateur 3, dont les valeurs sont telles que le circuit résonne à la fréquence désirée, par exemple de 25'k.Hertz dans le cas précité d'un appareil ménager. La self 2 fait alors office d'enroulement primaire, le secondaire étant constitué par la charge à chauffer, dans l'appareil correspondant, en l'occurrence un ustensile de cuisson (casserole, poêle, etc...).This includes a plane inductor 2 mounted in parallel with a capacitor 3, the values of which are such that the circuit resonates at the desired frequency, for example 25'k.Hertz in the above-mentioned case of a household appliance. The inductor 2 then acts as the primary winding, the secondary being constituted by the charge to be heated, in the corresponding appliance, in this case a cooking utensil (saucepan, frying pan, etc.).

Conformément à la caractéristique essentielle du dispositif selon l'invention, le circuit oscillant 1 est relié aux deux lignes 5 et 6 du circuit d'alimentation par l'intermédiaire de deux interrupteurs électroniques, qui se trouvent donc disposés de part et d'autre de ce circuit oscillant. Dans l'exemple représenté à la figure 1, chacun de ces interrupteurs est constitué par un tyristor 7 avec lequel est montée en anti-parallèle une diode 8 dont le sens de conduction est donc inverse.In accordance with the essential characteristic of the device according to the invention, the oscillating circuit 1 is connected to the two lines 5 and 6 of the supply circuit by means of two electronic switches, which are therefore located on either side of this oscillating circuit. In the example shown in Figure 1, each of these switches consists of a tyristor 7 with which is mounted in anti-parallel a diode 8 whose direction of conduction is therefore opposite.

La gachette de chacun des tyristors 7 est reliée à un circuit de commande très simplifié dans l'exemple et désigné parla référence générale- 9. L'agencement de ce circuit est tel que les tyristors fonctionnent à la fréquence de résamance du circuit oscillant 1 en s'ouvrant et en se fermant en même temps. Ce circuit comprend un. oscillateur de comnande 10 de type astable, suivi. d'un, voire de plusieurs, transiston(s) permettant d'obtenir des impulsions de commande compatibles en durée, en polarité et en puissance pour commander correctement les interrupteurs, de puissance.The trigger of each of the tyristors 7 is connected to a very simplified control circuit in the example and designated by the general reference. The arrangement of this circuit is such that the tyristors operate at the resamance frequency of the oscillating circuit 1 in opening and closing at the same time. This circuit includes a. astable type 10 control oscillator, tracking. one, or even several, transiston (s) making it possible to obtain control pulses compatible in duration, in polarity and in power to correctly control the switches, of power.

Cependant, l'agencement d'un tel circuit n'est pas complet, tel que présenté ci-rlessous. En effet, il faut tenir compte du fait que les interrupteurs de puissance ne se désamorcent pas lorsque l'impulsion sur l'électrode de: commande tombe à zéro volt. Pour attein- dre ce but, il faut inverser la polarité à ses bornes (anode-cathode).However, the arrangement of such a circuit is not complete, as presented below. In fact, it must be taken into account that the power switches do not defuse when the pulse on the control electrode drops to zero volts. To reach this goal, it is necessary to reverse the polarity at its terminals (anode-cathode).

Le circuit bouchon est tout à fait adéquat pour assurer ce rôle supplémentaire. En effet, les phénomènes, de surtension de tels circuits sent bien connus.The plug circuit is perfectly adequate to fulfill this additional role. Indeed, the phenomena of overvoltage of such circuits feels well known.

Cependant, il existe une difficulté due à la faible valeur selfique utilisée (34 µH) dans le présent exemple. En effet, cette faible valeur provoque l'ouverture des tyristors en 2,5 µseccndes, ce qui n'est pas suffisant pour charger correctement le circuit oscillant, en maintenant la fréquence de travail envisagée.However, there is a difficulty due to the low inductive value used (34 μH) in the present example. Indeed, this low value causes the opening of the tyristors in 2.5 µseccndes, which is not enough to correctly load the oscillating circuit, maintaining the working frequency envisaged.

Cependant, une augmentation de la valeur de la self 2 n'est pas envisageable, car ses dimensions mécaniques deviendraient vite inexploitables et, de plus, il serait difficile de trouver des récipients pouvant s'apairer à la self. Il est donc inutile d'énumérer tou - tes les autres raisons.However, an increase in the value of the inductor 2 cannot be envisaged, since its mechanical dimensions would quickly become unusable and, moreover, it would be difficult to find containers that can be paired with the inductor. It is therefore unnecessary to list all the other reasons.

C'est pourquoi, dans le but de conserver une fréquence de rêsonnance de 25 à 30 k.Hz et un temps de conduction des interrupteurs de l'ordre de 10 µseccndes, il est inclus, dans la ligne qui alimente le circuit résonnant, une petite self 13 de 3,5 µHenri dans l'exemple. Cette self peut être constituée de différentes façons, par exemple sur air, sur noyau de différentes formes, ou plus simplement en passant le fil d'alimentation du circuit oscillant dans un tore de bonne valeur.This is why, in order to maintain a resonance frequency of 25 to 30 k.Hz and a conduction time of the switches of the order of 10 µseccndes, it is included, in the line which supplies the resonant circuit, a small self 13 of 3.5 µHenri in the example. This inductor can be formed in different ways, for example on air, on a nucleus of different shapes, or more simply by passing the power wire of the oscillating circuit through a toroid of good value.

Cette petite self a pour effet de ralentir ou plutôt de retarder l'action de la self de chauffe 2, ce qui se traduit par un temps de ccnduction des tyristors de l'ordre de 10 µsecondes dans l'exemple.This small choke has the effect of slowing down or rather delaying the action of the heating choke 2, which results in a induction time of the tyristors of the order of 10 μseconds in the example.

Tout ceci apparaîtra plus clairement en décomposant les- différentes phases de conduction et d'oscillation libre du circuit, lesquelles apparaissent sur les courbes de variation des tensions aux bornes des deux interrupteurs électroniques. Celles-ci sont représentées à la figure 2, sur laquelle :

  • A est la phase de conduction (interrupteur fermé)
  • B est la phase de conduction des diodes
  • C est la phase d'oscillation libre
All this will appear more clearly by decomposing the different phases of conduction and free oscillation of the circuit, which appear on the curves of variation of the voltages at the terminals of the two electronic switches. These are shown in Figure 2, in which:
  • A is the conduction phase (switch closed)
  • B is the conduction phase of the diodes
  • C is the free oscillation phase

1. Phase de fermeture des deux interrupteurs-1. Closing phase of the two switches-

Dans cette phase, le circuit oscillant se- charge en énergie à travers les deux tyristors 7 de puissance. Le circuit bouchon se trouve alors normalement référencé entre les lignes 5 et 6 du circuit d'alimentation.In this phase, the oscillating circuit is charged with energy through the two power tyristors 7. The plug circuit is then normally referenced between lines 5 and 6 of the supply circuit.

2. Phase d'ouverture des deux interrupteurs2. Opening phase of the two switches

C'est dans cette phase que se manifeste l'originalité du dispositif selon l'invention.It is in this phase that the originality of the device according to the invention manifests itself.

En effet, les surtensions du circuit bouchon survenant 10 µs après la fermeture des tyristors ont pour effet de polariser en inverse les tyristors, qui se bloquent. Les tensions supérieures aux références sent écoulées par les diodes 8 et le circuit bouchon part en oscillation libre.Indeed, the overvoltages of the plug circuit occurring 10 µs after the closing of the tyristors have the effect of reverse biasing the tyristors, which are blocked. The voltages higher than the references are passed by the diodes 8 and the plug circuit leaves in free oscillation.

.Dès cet instant, le circuit oscillant (assimilable dans cette phase à un générateur d'énergie) va, pour se référencer, trouver à ses bornes les interrupteurs 7 ouverts. Ces derniers servent donc de référence au circuit oscillant, ce qui a pour effet d'essayer de centrer les tensions aux bornes de ce circuit entre deux très grandes impédances..As of this moment, the oscillating circuit (comparable in this phase to an energy generator) will, for reference, find at its terminals the open switches 7. The latter therefore serve as a reference for the oscillating circuit, which has the effect of trying to center the voltages across the terminals of this circuit between two very large impedances.

Le centrage exact des tensions est directement lié aux paramètres internes des interrupteurs.The exact centering of the voltages is directly linked to the internal parameters of the switches.

Aussi, pour éviter un tri des carposants, afin de les apai rer, il est intéressant de monter en parallèle avec chaque tyristor, un condensateur de petite valeur 11 et une résistance 12. Ceci permet d'équilibrer convenablement les tensions aux bornes de chaque tyristor 7.Also, to avoid sorting the components, in order to appease them, it is advantageous to mount in parallel with each tyristor, a small value capacitor 11 and a resistor 12. This makes it possible to properly balance the voltages at the terminals of each tyristor 7.

En conséquence, chaque interrupteur supporte à ses bornes la moitié de la tension développée par le circuit oscillante soit 300 volts dans l'exemple.Consequently, each switch supports at its terminals the half of the voltage developed by the oscillating circuit, ie 300 volts in the example.

Il est à remarquer que la tension développée par ce type de circuit oscillant est plus faible que dans d' autres types de circuits oscillants. En l'occurrence, cette-tensicn est de l'ordre de 600 à 700 volts au lieu de 800 à 900 volts.It should be noted that the voltage developed by this type of oscillating circuit is lower than in other types of oscillating circuits. In this case, this-tensicn is of the order of 600 to 700 volts instead of 800 to 900 volts.

Ce fait est dû à la faible valeur selfique 34 µHenri, qui cumule les fonctions d'enroulement primaire et moyen de décharge. Or, cette faible valeur permet d'écouler,plus rapidement que dans d'autres types de circuits,l'énergie emmagasinée dans la capacité 3, d'où des tensions développées plus basses.This fact is due to the low inductive value 34 µHenri, which combines the functions of primary winding and means of discharge. However, this low value allows the energy stored in capacity 3 to flow faster than in other types of circuits, hence lower developed voltages.

D'autre part, le fait que les tyristors ne voient que la demi-tension présente aux bornes du circuit oscillant, offre de multiples avantages, dont les principaux sont :

  • 1. En conservant des tyristors de mêmes caractéristiques que sur un montage à un interrupteur (tenue en tension 1000 V), ce nouveau système offre une marge de sécurité pour une. tension de 1400 V dans l'exemple.
  • 2. La marge de sécurité de tension peut être réduite en augmentant la tension d'alimentation si l'on désire augmenter la puissance.
  • 3. Il est possible, en gardant une marge raisonnable de sécurité de tension (600 V par exemple) d'utiliser des tyristors moins performants en tension.
  • 4. Il est évidemnent toujours possible, pour augmenter la puissance, de multiplier le nombre de paires de tyristors par montage.
On the other hand, the fact that the tyristors only see the half-voltage present at the terminals of the oscillating circuit, offers multiple advantages, the main ones being:
  • 1. By retaining tyristors with the same characteristics as on a switch assembly (voltage withstand 1000 V), this new system offers a safety margin for one. 1400 V voltage in the example.
  • 2. The voltage safety margin can be reduced by increasing the supply voltage if you want to increase the power.
  • 3. It is possible, while keeping a reasonable margin of voltage safety (600 V for example) to use tyristors less efficient in voltage.
  • 4. It is obviously always possible, to increase the power, to multiply the number of pairs of tyristors per assembly.

La conception particulière du dispositif selon l'invention multiplie donc largement les coefficients de sécurité, puisque les tensions aux bornes des interrupteurs sont divisées par deux.The particular design of the device according to the invention therefore greatly multiplies the safety coefficients, since the voltages at the terminals of the switches are divided by two.

Il faut également observer que cette conception a pour avantage d'éliminer les inconvénients habituels des dispositifs électroniques de chauffage par induction, parmi lesquels les risques d'emballement thermique des composants actifs (interrupteur de puissance). En effet, dans ce cas de figure, un interrupteur protège efficacement l'autre, sachant que les composants ne sont jamais parfaitement identiques, et de plus, jamais exposés aux mêmes températures.It should also be noted that this design has the advantage of eliminating the usual drawbacks of electronic induction heating devices, including the risks of thermal runaway of the active components (power switch). Indeed, in this case, a switch effectively protects the other, knowing that the components are never perfectly identical, and moreover, never exposed to the same temperatures.

D'autre part, les courants de fuite sont diminués par le montage de deux interrupteurs, ce qui offre une bonne garantie contre l'emballement thermique.On the other hand, the leakage currents are reduced by the mounting of two switches, which offers a good guarantee against be the thermal runaway.

Mais, ainsi qu'il a déjà été indiqué, le principal avantage du dispositif selon l'invention réside dans le fait que, pour un même voltage du circuit oscillant, la marge de sécurité tension des interrupteurs électroniques se trouve considérablement augmentée.However, as already indicated, the main advantage of the device according to the invention lies in the fact that, for the same voltage of the oscillating circuit, the voltage safety margin of the electronic switches is considerably increased.

Cependant, il va de soi que le dispositif selon l'invention n'est pas limité au seul exemple préférentiel décrit ci-dessus. Ainsi, le circuit oscillant de ce dispositif peut être réalisé différemment.. D'autre part, les tyristors de puissance pourraient être remplacés par des transistors de puissance, moyennant quelques retouches inhérentes au matériel employé.However, it goes without saying that the device according to the invention is not limited to the single preferred example described above. Thus, the oscillating circuit of this device can be produced differently. On the other hand, the power tyristors could be replaced by power transistors, with a few touch-ups inherent in the equipment used.

Du reste, la figure 3 représente le schéma d'une forme de réalisation dans laquelle les tyristors 7 du précédent exemple sont remplacés par des transistors 7a.Furthermore, FIG. 3 represents the diagram of an embodiment in which the tyristors 7 of the previous example are replaced by transistors 7a.

Par ailleurs, il va de soi que le présent dispositif n'est pas limité à la réalisation d'appareils de cuisson à usage ménager, car il peut faire l'objet d'applications diverses.Furthermore, it goes without saying that the present device is not limited to the production of cooking appliances for household use, since it can be the subject of various applications.

Claims (3)

1. Dispositif électronique de chauffage à induction, comportant un circuit oscillant conprenant un condensateur et une self qui fait office d'enroulement primaire, l'enroulement secondaire étant constitué par la charge à chauffer, caractérisé en
Figure imgb0001
par deux interrupteurs électraniques- par exemple deux tyristors (7) - assujettis à deux circuits de commande (9) les faisant fonctionner à la fréquence de résonnance du circuit oscillant (2-3) pour s'ouvrir et se fermer en même temps, ces interrupteurs jouant le rôle d'impédances de très grande valeur lors de leur ouverture.1. Electronic induction heating device, comprising an oscillating circuit comprising a capacitor and a choke which acts as primary winding, the secondary winding being constituted by the load to be heated, characterized in
Figure imgb0001
by two electronic switches - for example two tyristors (7) - subject to two control circuits (9) operating them at the resonant frequency of the oscillating circuit (2-3) to open and close at the same time, these switches playing the role of very high impedances when they are opened. 2. Dispositif selon la revendication 1, caractérisé en ce que dans l'une des lignes d'alimentation du circuit oscillant, il est prévu une self (13) ayant pour fonction de retarder l'action de la self ( 2) du circuit oscillant.2. Device according to claim 1, characterized in that in one of the supply lines of the oscillating circuit, there is provided a choke (13) having the function of delaying the action of the choke (2) of the oscillating circuit . 3. Dispositif selon la revendication 1, caractérisé en ce qu'une résistance (12) et une capacité (11) sont montées en parallèle avec chaque interrupteur électronique .(7) pour centrer les tensions du circuit oscillant (2-3).3. Device according to claim 1, characterized in that a resistor (12) and a capacitor (11) are mounted in parallel with each electronic switch. (7) for centering the voltages of the oscillating circuit (2-3).
EP81401726A 1980-12-05 1981-10-28 Electronic induction heating arrangememt Expired EP0054445B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81401726T ATE15576T1 (en) 1980-12-05 1981-10-28 ELECTRONIC INDUCTION HEATING DEVICE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8025847A FR2495876B1 (en) 1980-12-05 1980-12-05 ELECTRONIC INDUCTION HEATING DEVICE
FR8025847 1980-12-05

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EP0054445A1 true EP0054445A1 (en) 1982-06-23
EP0054445B1 EP0054445B1 (en) 1985-09-11

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EP81401726A Expired EP0054445B1 (en) 1980-12-05 1981-10-28 Electronic induction heating arrangememt

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EP (1) EP0054445B1 (en)
AT (1) ATE15576T1 (en)
DE (1) DE3172256D1 (en)
FR (1) FR2495876B1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0269417A1 (en) * 1986-11-25 1988-06-01 Creda Limited Induction heating circuits for cooking appliances
GB2197995A (en) * 1986-11-25 1988-06-02 Ti Creda Ltd Induction heating circuits for cooking appliances
FR2712763A1 (en) * 1993-11-15 1995-05-24 Moulinex Sa Corrugated current generator with saturable self.
WO1995022237A1 (en) * 1994-02-10 1995-08-17 Aktiebolaget Electrolux An energy converter for heating units for foodstuffs
WO1995024817A1 (en) * 1994-03-09 1995-09-14 Aktiebolaget Electrolux A circuit for the control of energy supply in a resonance converter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2180584A1 (en) * 1972-04-21 1973-11-30 Thomson Csf
DE2634667A1 (en) * 1975-08-04 1977-02-17 Ajax Magnethermic Corp PERFORMANCE CONTROLLER
FR2430679A1 (en) * 1978-07-04 1980-02-01 Orega Electro Mecanique Safety circuit for induction heated hotplates - has bimetallic switches protecting circuitry and utensil bearing surfaces

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2180584A1 (en) * 1972-04-21 1973-11-30 Thomson Csf
DE2634667A1 (en) * 1975-08-04 1977-02-17 Ajax Magnethermic Corp PERFORMANCE CONTROLLER
FR2430679A1 (en) * 1978-07-04 1980-02-01 Orega Electro Mecanique Safety circuit for induction heated hotplates - has bimetallic switches protecting circuitry and utensil bearing surfaces

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0269417A1 (en) * 1986-11-25 1988-06-01 Creda Limited Induction heating circuits for cooking appliances
GB2197995A (en) * 1986-11-25 1988-06-02 Ti Creda Ltd Induction heating circuits for cooking appliances
GB2197995B (en) * 1986-11-25 1991-06-19 Ti Creda Ltd Improvements in or relating to induction heating circuits for cooking appliances
FR2712763A1 (en) * 1993-11-15 1995-05-24 Moulinex Sa Corrugated current generator with saturable self.
WO1995014364A1 (en) * 1993-11-15 1995-05-26 Moulinex S.A. Ripple current generator with a saturable self-inducting coil
WO1995022237A1 (en) * 1994-02-10 1995-08-17 Aktiebolaget Electrolux An energy converter for heating units for foodstuffs
US6043470A (en) * 1994-02-10 2000-03-28 Aktiebolaget Electrlux Energy converter for electromagnetic induction heating units for foodstuffs
WO1995024817A1 (en) * 1994-03-09 1995-09-14 Aktiebolaget Electrolux A circuit for the control of energy supply in a resonance converter
US5914066A (en) * 1994-03-09 1999-06-22 Aktiebolaget Electrolux Circuit for the control of energy supply in a resonance converter

Also Published As

Publication number Publication date
ATE15576T1 (en) 1985-09-15
FR2495876A1 (en) 1982-06-11
DE3172256D1 (en) 1985-10-17
EP0054445B1 (en) 1985-09-11
FR2495876B1 (en) 1985-06-07

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