EP2194754A1 - Agencement de capteur pour la détection d'un appareil de cuisson - Google Patents

Agencement de capteur pour la détection d'un appareil de cuisson Download PDF

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Publication number
EP2194754A1
EP2194754A1 EP08021142A EP08021142A EP2194754A1 EP 2194754 A1 EP2194754 A1 EP 2194754A1 EP 08021142 A EP08021142 A EP 08021142A EP 08021142 A EP08021142 A EP 08021142A EP 2194754 A1 EP2194754 A1 EP 2194754A1
Authority
EP
European Patent Office
Prior art keywords
cookware
sensor
differential signal
heating element
sensor arrangement
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.)
Withdrawn
Application number
EP08021142A
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German (de)
English (en)
Inventor
Andrei Uhov
Roberto Giordano
Filippo Tisselli
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.)
Electrolux Home Products Corp NV
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Electrolux Home Products Corp NV
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 Electrolux Home Products Corp NV filed Critical Electrolux Home Products Corp NV
Priority to EP08021142A priority Critical patent/EP2194754A1/fr
Publication of EP2194754A1 publication Critical patent/EP2194754A1/fr
Withdrawn legal-status Critical Current

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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
    • H05B3/00—Ohmic-resistance heating
    • H05B3/68—Heating arrangements specially adapted for cooking plates or analogous hot-plates
    • H05B3/74—Non-metallic plates, e.g. vitroceramic, ceramic or glassceramic hobs, also including power or control circuits
    • H05B3/746—Protection, e.g. overheat cutoff, hot plate indicator
    • 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
    • H05B2213/00—Aspects relating both to resistive heating and to induction heating, covered by H05B3/00 and H05B6/00
    • H05B2213/05—Heating plates with pan detection means

Definitions

  • the present invention in particular relates to a sensor arrangement for cookware detection.
  • Metal sensitive cookware detection systems are used for semi-automatically operating cooking hobs of household cooking apparatus. Such cookware detection systems are used for activating or deactivating a cooking hob dependent on the absence and presence, respectively, of the cookware on the cooking hob. If, for example, a cookware is removed from the cooking hob the cooking hob can be deactivated for security reasons and/or for saving energy. Likewise, it is possible to activate or deactivate heating circuits of a single cooking hob dependent on the position or coverage of the cookware compared to the cooking hob.
  • Such systems using capacitive or optical measurement principles are known from EP 0 374 868 A1 , EP 0 883 327 B1 , GB 2 335 551 A and US 6 259 069 B1 , for example.
  • Optical measurement systems are suitable for non-metallic cookware, as well.
  • This problem can be at least partially reduced to metal containing cookware if detection systems using capacitive measurement principles are used.
  • Such systems can use metal induced changes of capacitors.
  • Another possibility to selectively detect metal containing cookware consists in using inductive measurement principles.
  • impacts of metal containing cookware on inductances are used for cookware detection.
  • Such systems are known from DE 100 42 775 A1 , DE 600 28 485 and DE 601 19 016 , for example.
  • a sensor arrangement for determining the presence/absence and/or position of a metal containing cookware with a heating element of a cooking appliance.
  • the sensor arrangement comprises metal sensitive first and second sensors, preferably of inductive type.
  • the first and second sensors are designed for respectively generating first and second sensor signals.
  • the first and second sensor signals are indicative of metal containing cookware positioned - at least partially - on the heating element.
  • a circuitry designed for obtaining a differential signal value of the first and second signals'.
  • the differential signal value being a compensation value of the first and second signal or representing their difference for example, can be used to determine the presence or absence of the metal containing cookware with the heating element.
  • the sensor arrangement is for semi-automatically operating the cooking appliance, particularly for reasons of secure and energy effective operation of the cooking appliance.
  • metal containing cookware can be recognized by signal changes with the first and/or second sensor signals.
  • signal changes usually are relatively small compared to absolute signal values of the first and second sensors, complicating effective cookware detection and/or localization.
  • the differential signal value is used for cookware detection and/or localization.
  • small signal changes can be observed nearly irrespective of the absolute signal values of the first and second sensors. Therefore, even small signal changes can be determined with high accuracy using common amplification techniques, for example. As a result, it is possible to reliably and accurately determine the presence/absence and/or position of the cookware.
  • the sensor arrangement according to the invention can be easily implemented and be used with nearly any cooking appliance.
  • the first and second sensor can be of inductive type.
  • each sensor may comprise a receiver coil and a transmitter coil.
  • the transmitter coils are designed for respectively generating electromagnetic fields for respectively inducing the first and second sensor signals in corresponding receiver coils.
  • a metal containing cookware on or put on the heating element gives rise to changes in the first and/or second signal, depending inter alia on the distance between the respective first and second sensor and the cookware.
  • the differential signal value as for example the difference between the first and second signal, will also be changed.
  • the transmitter and receiver coils can, in general, be of any type and shape. In particular, they can be of rectangular coil type. Windings of corresponding transmitter and receiver coils can be arranged in a common plane. Each transmitter coil preferably surrounds the respective receiver coil. Such coils types and shapes allow for flat shaped and space saving sensor arrangements.
  • the first and second sensors and the circuitry can be designed such that absent any metal containing cookware the differential signal value is close to zero. This is of particular advantage if surroundings of the first and second sensors in their final mounting position are different with regard to non-cookware metal objects.
  • the sensor arrangement can be implemented with almost any heating element in particular with cooking hobs, and more specifically with hobs powered by electricity or gas.
  • the first and second sensors can be positioned offset parallel to a plane spanned by the cooking bob.
  • One of the first and second sensors can be positioned within an effective cooking hob area.
  • the other one of the first and second sensors can be positioned at a border area or outside the effective cooking bob area.
  • An effective cooking hob area shall be understood to be an area of the cooking hob, which area has a given size and can be selectively heated.
  • a single cooking hob may comprise one or more effective cooking hob areas.
  • a sensor arrangement may be provided for the cooking hob as a whole or for each effective cooking hob area.
  • the circuitry can make up a compensating circuit combination of the first and second sensor signals.
  • a compensating circuit combination the first and second signal will greatly cancel out each other if no cookware is present, provided that values of first and second signals are widely similar. Cookware induced changes in the first and second signal will lead to a noticeable change in the differential signal value.
  • the first and second sensor signals are alternating current signals that are phase shifted by 180 degrees, for example, a bucking circuitry leads to a compensation of the first and second signals in absence of a cookware.
  • electronic components for determining the differential signal from the first and second signals can be used.
  • a cooking appliance which can be a household cooking appliance.
  • the cooking appliance comprises at least one electricity or gas powered heating element and at least one sensor arrangement according to the first aspect of the invention.
  • the at least one sensor arrangement is assigned to at least one of the at least one heating element.
  • one or more sensor arrangements are assigned to a single heating element. Further combinations are conceivable.
  • advantages of the cooking appliance reference is made to the advantages of the first aspect of the invention.
  • a method of determining the presence/absence and/or position of a metal containing cookware with a heating element of a cooking appliance is provided.
  • the method comprises the steps of:
  • the fist and second sensor signals can be generated by powering respective transmitter coils by alternating currents to generate respective electromagnetic fields.
  • the electromagnetic fields in turn effect alternating induction currents, i. e. first and second sensor signals, in respective receiver coils.
  • first and second sensor signals are phase shifted by 180 degrees. In this case it is possible that a simple summation of the first and second signals cancel out each other in absence of a cookware. Therefore the differential signal can be obtained in a simple way.
  • Other possibilities for obtaining the differential signal are conceivable. For example it is possible to use electronic components designed for subtracting in-phase first and second sensor signals, for example.
  • the presence of a cookware can be determined by comparing the differential signal value with a preset threshold. If, for example, the differential signal value exceeds or is below the threshold, presence or absence of a cookware can be assumed.
  • determining the position of the cookware relative to the heating element it is possible to use information about a mounting position of at least one of the first and second sensors in combination with a signal value of the differential signal. For reasons of accuracy, it is of advantage if at least the mounting position of the sensor positioned within the cooking area is used.
  • FIG 1 illustrates a schematic representation of a sensor arrangement 1 according to the first aspect of the invention.
  • the sensor arrangement 1 comprises a metal sensitive first sensor 2 and a metal sensitive second sensor 3 positioned offset from the first sensor 2.
  • the first 2 and second sensors 3 are of inductive type. Hence each of the first 2 and second sensors 3 comprises a receiver coil 4 and a transmitter coil 5.
  • the transmitter coils 5 are connected in series.
  • the receiver coils 4 are connected by circuitry 6 to make up a compensating or bucking circuit combination.
  • both the transmitter coils 5 and receiver coils 4 are of rectangular coil type. Windings of the receiver coils 4 are arranged within windings of the corresponding transmitter coils 5. The windings of each sensor 2, 3 preferably lie in a common plane.
  • the electromagnetic fields induce alternating currents in the receiver coils 4, i. e. first and second sensor signals.
  • FIG 2 shows the signal behaviour over time of first and second receiver coil sensor signals induced by the electromagnetic fields of the transmitter coils 5. Abscissa and ordinate are given in arbitrary units (a.u.).
  • FIG 2a and 2b diagram in solid lines the first and second sensor signals of the first 2 and second sensors 3 in absence of any metal containing cookware.
  • the first and second sensor signals show sinusoidal behaviour. Due to the bucking circuit combination of the receiver coils 4 the first and second signals are phase shifted by 180 degrees.
  • the first and second sensor signals compensate each other. Therefore a differential signal value of the first and second sensor signal is close to zero.
  • the differential signal value Due to the shift in the first sensor signal and still the same second sensor signal, the differential signal value will be no longer close to zero.
  • the differential signal value is representative of a metal object, such as a metal cookware, being present or absent, or more generally speaking in close proximity of the first sensor.
  • the differential signal value can be amplified for more accurate detection of the presence of absence of a metal object.
  • the time course of amplified differential signal value is depicted in FIG 2c .
  • a preset threshold T can be used, as indicated in FIG 2c . If the absolute value of the differential signal value exceeds the threshold T the presence of a metal object is assumed. If the absolute value of the differential value is below the threshold T it is assumed that no metal object is present.
  • FIG 3 schematically illustrates a top view of a cooking appliance 7.
  • the cooking appliance 7 is a household cooking appliance comprising two cooking hobs 8 which may be gas-powered hobs or of any other type.
  • a sensor arrangement 1 is assigned to each cooking hob 8.
  • the sensor arrangements 1 make it possible to determine the presence or absence of a metal containing cookware 9 with the respective cooking hob 8. In this way cooking processes can be semi-automated. Further the operation of the cooking hobs 8 can be controlled for reasons of energy consumption and security reasons. The latter is of special advantage for gas-powered cooking hobs, as the gas-feed can be interrupted if the cookware is removed from the cooking hob 8.
  • the first 2 and second sensors 3 of each of the sensor arrangements 1 are positioned offset from each other in a plane below and parallel to a plane spanned by the respective cooking hob 8.
  • the first sensors 2 are positioned within an effective cooking area of the respective cooking hob 8.
  • the second sensors 3 are positioned outside the respective cooking area.
  • Positioning the metal containing cookware 9, like a pot for example, on the cooking hob 8 on the left-hand side in FIG 3 will influence the first sensor 2 and therefore change the first sensor signal as described on connection with FIG 2a .
  • This change can be detected by means of the differential signal as described in connection with FIG 2 .
  • the differential signal value exceeds the threshold T, the presence of a cookware can be assumed, and the cooking hob 8 can be activated.
  • the sensor arrangement of cooking hob 8 on the right-hand side in FIG 3 is not significantly influenced by cookware 9. Therefore the respective differential signal value rests below the threshold T and the right-hand cooking hob 8 is kept inactivated.
  • the influence the cookware exerts on the first sensor 2 is inter alia dependent on the distance between cookware, i. e. metal object, and first sensor 2.
  • the nearer the metal part of the cookware the bigger the signal change and hence the bigger the absolute value of the differential signal value.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Induction Heating Cooking Devices (AREA)
EP08021142A 2008-12-05 2008-12-05 Agencement de capteur pour la détection d'un appareil de cuisson Withdrawn EP2194754A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP08021142A EP2194754A1 (fr) 2008-12-05 2008-12-05 Agencement de capteur pour la détection d'un appareil de cuisson

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP08021142A EP2194754A1 (fr) 2008-12-05 2008-12-05 Agencement de capteur pour la détection d'un appareil de cuisson

Publications (1)

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EP2194754A1 true EP2194754A1 (fr) 2010-06-09

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EP08021142A Withdrawn EP2194754A1 (fr) 2008-12-05 2008-12-05 Agencement de capteur pour la détection d'un appareil de cuisson

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3799527A1 (fr) * 2019-09-27 2021-03-31 E.G.O. Elektro-Gerätebau GmbH Plaque de cuisson à induction et procédé de commande d'une plaque de cuisson à induction
US20210337635A1 (en) * 2020-04-23 2021-10-28 Powermat Technologies Ltd. Heating coil design for wireless power systems

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2055030A (en) * 1979-07-31 1981-02-18 Matsushita Electric Ind Co Ltd Circuit for detecting a utensil load placed asymmetrically relative to an induction heating coil
EP0374868A1 (fr) 1988-12-23 1990-06-27 INDUSTRIEELEKTRONIK DR.ING. WALTER KLASCHKA GMBH & CO. Plaque de cuisson
WO1998051128A1 (fr) * 1997-05-07 1998-11-12 Compagnie Europeenne Pour L'equipment Menager - Cepem Foyer de cuisson a detection de la presence d'un recipient
GB2335551A (en) 1998-03-16 1999-09-22 Santis Danilo De Heater control with object detector
EP1087641A2 (fr) * 1999-09-23 2001-03-28 Cherry GmbH Système de détection d'objet, qui par exemple détecte la présence d'un ustensile de cuisine métallique sur une surface de cuisson non-métallique
US6242721B1 (en) * 1997-01-11 2001-06-05 Schott Glas Cooktop with a non-metallic hotplate
US6259069B1 (en) 1999-09-22 2001-07-10 Diehl Ako Stiftung & Co. Kg Apparatus for detecting the presence of a cooking vessel
DE10042775A1 (de) 2000-08-31 2002-03-14 Diehl Ako Stiftung Gmbh & Co Topferkennung
EP1229301A1 (fr) * 2001-01-24 2002-08-07 Texas Instruments Incorporated Capteur de position inductif à courant de Foucault avec di/dt élevé
EP0883327B1 (fr) 1997-06-03 2004-09-08 Diehl AKO Stiftung & Co. KG Arrangement pour la transmission sans fil de la température et pour la détection d'un récipient de cuisson sur une cuisinière
DE102006043182A1 (de) * 2005-09-19 2007-04-19 BSH Bosch und Siemens Hausgeräte GmbH Vorrichtung mit einer Sensoranordnung zum Bestimmen einer Position eines metallischen Gegenstandes
DE60119016T2 (de) 2000-03-24 2007-05-10 Eika, S.Coop Sensorvorrichtung zum Erfassen der Anwesenheit eines Topfes auf einer Elektrokochplatte

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2055030A (en) * 1979-07-31 1981-02-18 Matsushita Electric Ind Co Ltd Circuit for detecting a utensil load placed asymmetrically relative to an induction heating coil
EP0374868A1 (fr) 1988-12-23 1990-06-27 INDUSTRIEELEKTRONIK DR.ING. WALTER KLASCHKA GMBH & CO. Plaque de cuisson
US6242721B1 (en) * 1997-01-11 2001-06-05 Schott Glas Cooktop with a non-metallic hotplate
WO1998051128A1 (fr) * 1997-05-07 1998-11-12 Compagnie Europeenne Pour L'equipment Menager - Cepem Foyer de cuisson a detection de la presence d'un recipient
EP0883327B1 (fr) 1997-06-03 2004-09-08 Diehl AKO Stiftung & Co. KG Arrangement pour la transmission sans fil de la température et pour la détection d'un récipient de cuisson sur une cuisinière
GB2335551A (en) 1998-03-16 1999-09-22 Santis Danilo De Heater control with object detector
US6259069B1 (en) 1999-09-22 2001-07-10 Diehl Ako Stiftung & Co. Kg Apparatus for detecting the presence of a cooking vessel
EP1087641A2 (fr) * 1999-09-23 2001-03-28 Cherry GmbH Système de détection d'objet, qui par exemple détecte la présence d'un ustensile de cuisine métallique sur une surface de cuisson non-métallique
DE60028485T2 (de) 1999-09-23 2006-12-14 Cherry Gmbh Objekterfassungssystem, welches zum Beispiel die Anwesenheit eines metallischen Kochgerätes auf einer nichtmetallischen Kochoberfläche erfasst
DE60119016T2 (de) 2000-03-24 2007-05-10 Eika, S.Coop Sensorvorrichtung zum Erfassen der Anwesenheit eines Topfes auf einer Elektrokochplatte
DE10042775A1 (de) 2000-08-31 2002-03-14 Diehl Ako Stiftung Gmbh & Co Topferkennung
EP1229301A1 (fr) * 2001-01-24 2002-08-07 Texas Instruments Incorporated Capteur de position inductif à courant de Foucault avec di/dt élevé
DE102006043182A1 (de) * 2005-09-19 2007-04-19 BSH Bosch und Siemens Hausgeräte GmbH Vorrichtung mit einer Sensoranordnung zum Bestimmen einer Position eines metallischen Gegenstandes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3799527A1 (fr) * 2019-09-27 2021-03-31 E.G.O. Elektro-Gerätebau GmbH Plaque de cuisson à induction et procédé de commande d'une plaque de cuisson à induction
US20210337635A1 (en) * 2020-04-23 2021-10-28 Powermat Technologies Ltd. Heating coil design for wireless power systems

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