EP0054445B1 - Elektronische Induktionsheizvorrichtung - Google Patents

Elektronische Induktionsheizvorrichtung Download PDF

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Publication number
EP0054445B1
EP0054445B1 EP81401726A EP81401726A EP0054445B1 EP 0054445 B1 EP0054445 B1 EP 0054445B1 EP 81401726 A EP81401726 A EP 81401726A EP 81401726 A EP81401726 A EP 81401726A EP 0054445 B1 EP0054445 B1 EP 0054445B1
Authority
EP
European Patent Office
Prior art keywords
switches
oscillating circuit
circuit
electronic
capacitor
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
EP81401726A
Other languages
English (en)
French (fr)
Other versions
EP0054445A1 (de
Inventor
Maurice Scholtes
Roger Eisenberg
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.)
Eugene Scholtes SA
Original Assignee
Eugene Scholtes SA
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 Eugene Scholtes SA filed Critical Eugene Scholtes SA
Priority to AT81401726T priority Critical patent/ATE15576T1/de
Publication of EP0054445A1 publication Critical patent/EP0054445A1/de
Application granted granted Critical
Publication of EP0054445B1 publication Critical patent/EP0054445B1/de
Expired legal-status Critical Current

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Classifications

    • 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 induction heating devices.
  • FR-A-2 430 679 describes a device intended for electric induction cooking formed by an oscillating circuit, consisting of capacitors and a choke which acts as an inductor, inductor to which the ferromagnetic charge to be heated is coupled .
  • the oscillating circuit is connected to the supply circuit by two thyristors subject to a control circuit, this circuit making the thyristors operate successively.
  • a resistor and a capacitor are mounted in parallel with each thyristor to limit the variations in voltages across their terminals.
  • the supply circuit acts as a DC voltage source, obtained by rectifying the mains voltage.
  • DE-A-2 634 667 it describes a device intended to supply energy to the inductor of an induction furnace, this energy being conveyed by an alternating current obtained by an inverter.
  • This inverter is connected to a DC power supply.
  • the aim of the present invention is 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 and this, so as to produce an induction heating device, the design of which is such that it has very high reliability, despite the performance limits of electronic components currently on the market.
  • the subject of the invention is an 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, this circuit oscillating being connected to the supply circuit by two electronic switches subject to 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 - are subject to a control oscillator making them operate at the resonant frequency of the oscillating circuit to open and close at the same time, these switches playing the role of impedances of very high value when they are opened.
  • the oscillating circuit is connected directly to the two supply lines and, thereby, loaded with energy.
  • the oscillating circuit 1 of the corresponding device is constituted by a circuit known under the name "circuit-plug".
  • 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 power circuit mentation by means of two electronic switches, which are therefore arranged on the other side of this oscillating circuit.
  • the oscillating circuit 1 is supplied by a direct current source, this current coming from the rectification of two half-waves of the mains voltage. It is however possible that the power supply to the oscillating circuit is provided by a DC voltage source.
  • each of the electronic switches is constituted by a thyristor 7 with which is mounted in anti-parallel a diode 8 whose direction of conduction is therefore opposite.
  • each of the thyristors 7 is connected to the secondary of a transformer 9, the primary of which is supplied by a control oscillator 10.
  • the arrangement of the control circuit thus formed is rel that the thyristors operate at the resonant frequency of the oscillating circuit 1 by opening and closing at the same time.
  • the oscillator 10 of the control circuit is of the astable type, and it is followed by one, or even several, transistor (s) making it possible to obtain compatible control pulses in duration, in polarity and in power to correctly control the power switches.
  • the plug circuit is perfectly adequate to fulfill this additional role. Indeed, the overvoltage phenomena of such circuits are 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 of delaying the action of the heating choke 2, which results in a conduction time of the tyristors of the order of 10 u. seconds in the example.
  • the oscillating circuit is charged with energy through the two power tyristors 7.
  • the plug circuit is then normally connected directly to lines 5 and 6 of the supply circuit.
  • the oscillating circuit (comparable in this phase to an energy generator) will find at its terminals the open switches 7. The voltage across these terminals is indirectly linked to the internal parameters of the switches.
  • each switch supports at its terminals half of the voltage developed by the oscillating circuit, ie 300 volts in the example.
  • the voltage developed by this type of oscillating circuit is lower than in other types of oscillating circuits. In this case, this voltage 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). In this case, one 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 some 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.

Landscapes

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

Claims (2)

1. Elektronische Induktions-Heizeinrichtung mit einem Oszillatorschaltkreis, der einen Kondensator und eine Induktionsspule aufweist, die eine Primärwicklung darstellt, und eine Sekundärwicklung für die Heizung aufweist, wobei die Oszillatorschaltung mit einer Versorgungsschaltung über zwei elektronische Unterbrecher angeschlossen ist, die von einem Steuerschaltkreis angesteuert werden, wobei jedem der Unterbrecher ein Widersand und ein Kondensator parallel geschaltet ist, dadurch gekennzeichnet, daß die beiden elektronischen Unterbrecher beispielsweise zwei Thyristoren (7) sind, die an einen Steueroszillator (10) angeschlossen sind, der sie mit der Resonanzfrequenz der Steuerschaltung (2-3) zum Öffnen und Schließen betätigt, wobei die Unterbrecher beim Öffnen sehr hohe lmpedanzen darstellen.
2. Einrichtung nach Anspruch 1, dadurch gekennzeichnet, daß in der einen der Versorgungsleitungen der Oszillatorschaltung eine Spule (13) vorgesehen ist, die die Funktion der Spule (2) der Oszillatorschaltung verzögert.
EP81401726A 1980-12-05 1981-10-28 Elektronische Induktionsheizvorrichtung Expired EP0054445B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81401726T ATE15576T1 (de) 1980-12-05 1981-10-28 Elektronische induktionsheizvorrichtung.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8025847A FR2495876B1 (fr) 1980-12-05 1980-12-05 Dispositif electronique de chauffage a induction
FR8025847 1980-12-05

Publications (2)

Publication Number Publication Date
EP0054445A1 EP0054445A1 (de) 1982-06-23
EP0054445B1 true EP0054445B1 (de) 1985-09-11

Family

ID=9248708

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81401726A Expired EP0054445B1 (de) 1980-12-05 1981-10-28 Elektronische Induktionsheizvorrichtung

Country Status (4)

Country Link
EP (1) EP0054445B1 (de)
AT (1) ATE15576T1 (de)
DE (1) DE3172256D1 (de)
FR (1) FR2495876B1 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2197995B (en) * 1986-11-25 1991-06-19 Ti Creda Ltd Improvements in or relating to induction heating circuits for cooking appliances
GB2198296B (en) * 1986-11-25 1990-08-08 Ti Creda Ltd Improvements in or relating to induction heating circuits for cooking appliances
FR2712763B1 (fr) * 1993-11-15 1996-02-02 Moulinex Sa Générateur de courant ondulé à self saturable.
WO1995022237A1 (en) * 1994-02-10 1995-08-17 Aktiebolaget Electrolux An energy converter for heating units for foodstuffs
AU1756595A (en) * 1994-03-09 1995-09-25 Aktiebolaget Electrolux A circuit for the control of energy supply in a resonance converter

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2180584B1 (de) * 1972-04-21 1976-01-16 Thomson Csf Fr
US4037044A (en) * 1975-08-04 1977-07-19 Ajax Magnethermic Corporation Power control system for single phase induction melting or heating furnace
FR2430679A1 (fr) * 1978-07-04 1980-02-01 Orega Electro Mecanique Circuit de securite, notamment de temperatures maximales, pour plaque de cuisson par induction

Also Published As

Publication number Publication date
ATE15576T1 (de) 1985-09-15
EP0054445A1 (de) 1982-06-23
FR2495876B1 (fr) 1985-06-07
FR2495876A1 (fr) 1982-06-11
DE3172256D1 (en) 1985-10-17

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