METHOD FOR OPERATING AN INDUCTION COOKTOP AND INDUCTION COOKTOP

Abstract

In order to detect on an induction cooktop whether a cooking vessel with an integrated controller or smart functionality is arranged over an induction heating coil, the induction heating coils emit a short individual code. The latter can be detected and evaluated by the cooking vessel such that the cooking vessel emits a signal corresponding to this code which is received by an external operating means or the induction cooktop to locally associate this cooking vessel with this induction heating coil. Transmission or transfer of energy as a code proceeds at a frequency of at least 50 kHz, wherein a code has a plurality of pulse sequences, each of which has at least two pulses.

Claims

1. A method for operating an induction cooktop having a plurality of induction heating coils, wherein: each said induction heating coil has a heating zone, a cooking vessel can be arranged to overlap with at least one said heating zone, each said induction heating coil is designed for transmission or transfer of energy in order to heat one said cooking vessel, wherein an inverter is provided to drive each said induction heating coil, each said cooking vessel has a transmit device with a transmit antenna for transmitting a signal as a function of energy received from one said induction heating coil, a heating zone of said induction heating coil at least in part overlaps with said cooking vessel, a receive means is provided for receiving signals from a transmit device of one said cooking vessel or all said transmit devices of said cooking vessels on said induction cooktop, a controller is provided which obtains said signals from said receive means and has information for transmission or transfer of energy of said induction heating coils or obtains said information, wherein said method has the following steps: at least one said cooking vessel is arranged over one said heating zone of one said induction heating coil, a plurality of said induction heating coils are driven for transmission or transfer of energy in a pattern, wherein duration and/or amplitude are varied as a code, wherein said code consists in that an amplitude of said transmitted or transferred energy within said code varies over time, and/or a duration of energy transfer varies, and/or a duration between two said energy transfers varies, and/or a number of said energy transfers varies, wherein transmission or transfer of said energy proceeds as a code at a frequency of at least 50 kHz, wherein one said code has at least one sequence of at least two pulses and forms a pulse sequence, if one said cooking vessel overlaps with one said heating zone of one said induction heating coil which has transferred energy with a specific code, said transmit device transmits to said receive means a signal or a sequence of a plurality of signals, which are uniquely dependent on said code and/or are associable with precisely said code, said controller obtains said signals received by said receive means and compares said signals with information about said energy transmitted or transferred by said induction heating coils as said codes, in order to establish which said transferred energy code from a specific induction heating coil fits with a received signal or a sequence of a plurality of signals, in order on said basis to associate said cooking vessel transmitting said signal or said sequence of a plurality of said signals with said heating zone or with said induction heating coil associated with said heating zone.

2. The method as claimed in claim 1, wherein one said cooking vessel has a receive coil in order to store an alternating magnetic field of an induction heating coil as electrical energy in order to emit the signal by means of the transmit antenna of the transmit device, wherein said magnetic field is used for said transfer of said energy.

3. The method as claimed in claim 1, wherein an energy storage means which is connected to said receive coil is provided in said cooking vessel, wherein said energy received by said receive coil is stored in said energy storage means and wherein a signal or a sequence of a plurality of signals is emitted by said transmit device corresponding to said stored energy.

4. The method as claimed in claim 1, wherein said transmission or said transfer of said energy in the case of said induction heating coils, for which it is unknown that or whether their heating zone is overlapped by one said cooking vessel, is frequently and/or regularly repeated to detect said cooking vessels arranged in said heating zone.

5. The method as claimed in claim 4, wherein said transmission or said transfer of said energy in the case of said induction heating coils is frequently and/or regularly repeated at a frequency or a time interval of less than 5 sec.

6. The method as claimed in claim 1, wherein said transmission or said transfer of said energy of said induction heating coils for detection of said cooking vessels arranged in said heating zone also proceeds at least in an event that a change in an extent of overlap of one said heating zone by one said cooking vessel is detected.

7. The method as claimed in claim 2, wherein said method is only carried out when one said cooking vessel with said receive coil and with one said transmit device has been discovered on said induction cooktop, wherein said cooking vessel also additionally has an integrated circuit and at least one sensor.

8. The method as claimed in claim 1, wherein one said code consists of pulses, of which at least two said pulses form said at least one pulse sequence, wherein said pulses are generated at an operating frequency or said resonant frequency of an oscillator circuit with said induction heating coil, wherein one said pulse has one or more oscillations.

9. The method as claimed in claim 8, wherein said pulse has one or more oscillations with a total duration of between 0.1 μsec and 50 μsec.

10. The method as claimed in claim 1, wherein, when all said induction heating coils are being driven for transfer of energy in order to detect said cooking vessels arranged in said heating zone, said energy is first of all transferred for a short time as a pulse, a pause is then provided, and then a plurality of different codes is generated by way of a varying number of short sequences energy transfers and pausing or by waiting for a specific multiple of a waiting time, and each of said induction heating coils is driven with a different code, but each said induction heating coil always recurrently with the same code, for transmission or transfer of energy with said code.

11. The method as claimed in claim 10, wherein said waiting time is between 5% and 20% of a duration of said codes.

12. The method as claimed in claim 1, wherein said controller stores which one said cooking vessel is arranged in said heating zone of which induction heating coil, wherein said controller detects cooking vessels newly arranged in a heating zone of one said induction heating coil in the same way.

13. The method as claimed in claim 1, wherein transmission or transfer of one said code is omitted for so long as, once one said induction heating coil has detected and associated one said cooking vessel, no change or movement of said cooking vessel in its heating zone is registered by a change in said operating parameters of said oscillator circuit with said induction heating coil, wherein a code is then not transmitted again to said or to all said induction heating coils until a change or movement of said cooking vessel in its heating zone is registered by one said induction heating coil or by other sensors.

14. The method as claimed in claim 1, wherein all said induction heating coils simultaneously begin to transfer a code as said transmission of energy.

15. The method as claimed in claim 1, wherein each said code first has a pulse or energy is briefly transferred for synchronization and, from said synchronization pulse onwards, each said induction heating coil has a different code.

16. The method as claimed in claim 15, wherein, after said synchronization pulse, at least two further pulses follow in a time interval within all said codes and a number of following pulses corresponds to a numbering of said induction heating coils.

17. The method as claimed in claim 16, wherein within a code said time interval is in each case identical until a final pulse before said next synchronization pulse.

18. The method as claimed in claim 1, wherein said transmit device sends a processed item off information or directly a number of said induction heating coil as a designation or a position of said induction heating coil on said induction cooktop as at least two pulse sequences, which has been evaluated from said code received from one said induction heating coil.

19. The method as claimed in claim 18, wherein said evaluation proceeds in said transmit device, wherein said position of said induction heating coil on said induction cooktop is sent as x/y coordinates.

20. An induction cooktop for carrying out the method as claimed in claim 1, wherein said induction cooktop has a plurality of said induction heating coils, wherein at least one said heating zone is associated with each said induction heating coil.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Further advantages and aspects of the invention are revealed by the claims and the following description of preferred exemplary embodiments of the invention, which are explained below with reference to the figures, in which:

[0044] FIG. 1 is a schematic representation of an induction cooktop according to the invention in an arrangement with a cooking vessel together with external operating unit placed on a heating zone of an induction heating coil,

[0045] FIG. 2 is a simplified representation of the functionalities of the smart cooking vessel,

[0046] FIGS. 3 to 11 show various codes.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0047] FIG. 1 shows is an arrangement 11 with an induction cooktop 13 according to the invention. The induction cooktop 13 has a cooktop plate 14 under which are arranged two induction heating coils 16a and 16b. In practice, there are advantageously more induction heating coils 16, for example four or six up to twenty or thirty in the above-stated hotplate cooktops.

[0048] The induction cooktop 13 furthermore has a cooktop controller 18 which is connected to functional units of an inverter device 20, a transmit/receive means 22 and an operating module 24 on the underside of the cooktop plate 14. These functional units are in each case of conventional design. A radio standard for the transmit/receive means 22 may in principle, as has been explained above, be of many and varied designs. It is advantageously selected from the above-stated options Bluetooth or BLE, but also Zigbee, WLAN or similar, and proprietary solutions without a generally applicable standard can be applied.

[0049] A heating zone is in each case formed above the induction heating coils 16a and 16b which has an area approximately corresponding to the area of the induction heating coils 16. A cooking vessel 27 is arranged in the heating zone 17a or has been set down there on the top of the cooktop plate 14. The cooking vessel 27 has a receive coil 32 in a recess 30 in its bottom 29. The receive coil 32 has few turns and is arranged on the underside of the bottom 29 in such a way that it lies exposed or is not shielded by the rest of the bottom from the magnetic field of the induction heating coil 16a. This is important for the previously described energy transfer. The receive coil 32 is connected to a cooking vessel module 34 which is shown in magnified view in FIG. 2.

[0050] An external operating means 46 is shown on the right in FIG. 1 which may on the one hand be a specific operating means for the induction cooktop 13 or alternatively a mobile terminal such as a tablet computer or a smartphone. The external operating means 46 has a large-area display, as is shown. It furthermore has, as is in particular known for the stated mobile terminals, a receive means, a transmit means and also a processor or integrated circuit. A radio standard here matches the transmit/receive means 22, thus advantageously Bluetooth or BLE. There is no need to say much about the external operating means 46; a cooking program of the kind explained above can run on it for example by means of an app or a specific program. The external operating unit is not absolutely necessary. Its functionality can likewise be integrated in an operating and control unit located within the cooktop.

[0051] FIG. 2 shows a magnified view of the cooking vessel module 34. The cooking vessel module 34 is connected to the receive coil 32 by means of an electrical connection in the form of a cable or the like. The cooking vessel 34 is electrically conductively connected in a similar manner to a temperature sensor 36, which is arranged outside thereof. and according to FIG. 1 is advantageously arranged in the interior of the cooking vessel 27, such that it is surrounded by the water or food being cooked therein and is capable of determining the temperature thereof. This temperature sensor can likewise be set into the bottom of the cooking vessel if the intention is to acquire not the temperature of the food being cooked but the temperature of the bottom. Instead of the temperature sensor 36, still further sensors such as pressure sensors, weight sensors or the like are alternatively or additionally conceivable.

[0052] The cooking vessel module 34 furthermore has an energy storage means 38 which is directly connected to the receive coil 32. This may be a secondary battery, advantageously it is an above-stated capacitor, since it does not to have to store a particularly large amount of energy, especially if Bluetooth or BLE or Zigbee is used for transmission, but is intended to do so in as quick and loss-free manner as possible.

[0053] An integrated circuit 40 is provided as a kind of controller in the cooking vessel module 34 which acquires the energy or the signals or pulses received by the receive coil 32, advantageously with regard to duration and/or interval and/or amplitude or also added energy stored in the energy storage means 38. The integrated circuit 40 drives a transmit device 42 with transmit antenna 44, advantageously constructed with the above-stated Bluetooth or BLE standard or Zigbee.

[0054] FIG. 3 shows one possible way in which, in the case of four induction heating coils I1 to I4, it is possible to create differentiation in each case after a synchronization pulse transmitted simultaneously to all induction heating coils by way of an amplitude of a subsequently transmitted pulse. The amplitude here increases incrementally with the higher number of the induction heating coil. The pulses with differing amplitude are here simultaneously transmitted, but can of course also be transmitted in time-offset manner. Each pulse sequence thus in this case too also has at least two pulses.

[0055] FIG. 4 shows, by way of example for two induction heating coils, a respective code over time t, above for the first induction heating coil I1 and below for the induction heating coil I2. The pulse sequences are in themselves indeed identical, three pulses with a respective pulse duration being in each case provided, wherein the pulse duration of the second pulse is twice as long as the first pulse and the third pulse three times as long as the first pulse. A pause as a time interval between the individual pulses of each pulse sequence also varies, the second pause between the second pulse and the third pulse being twice as long as the first pause between the first pulse and the second pulse. The pulse sequences are accordingly very characteristically and uniquely detectable. These pulse sequences are used for the two induction heating coils shown here, but are advantageously used for all the induction heating coils of the induction cooktop. These two pulse sequences are thus varied in order to establish over which induction heating coil a cooking vessel has been placed.

[0056] The time is here measured between two pulse sequences including ramp-up of the pulse sequence, in order to reduce the noise generated in the induction cooktop. Ramp-up should here be taken to mean incrementing a duty factor in power generation for the induction heating coil and/or as reducing the frequency within a short time. Energy transfer and the frequency spectrum of the pulse or pulses is accordingly controlled. FIG. 4 shows the duty factor, but the frequency also varies. In the case of induction heating coil I1, the time interval between the two identical pulse sequences amounts to A1 while in the case of induction heating coil I2, it amounts to A2 and is distinctly longer. For a further induction heating coil, the time interval Ax would then be still longer than A2.

[0057] FIG. 5 again shows two pulse sequences for an induction heating coil I1 and an induction heating coil I2. These pulse sequences shown in detail can, as in FIG. 4, in each case be used at least twice. This is, however, not mandatory. The second pulse sequence for induction heating coil I2 exactly corresponds to that from FIG. 4. In the first pulse sequence above for induction heating coil I1, the time interval A1 between the first pulse and the second pulse is exactly twice as long as the time interval A2 in the lower pulse sequence. As still another variation, the time interval between the second pulse and the third pulse could additionally or alternatively also be varied.

[0058] The various methods can accordingly be shown for the above-stated ramp-up, wherein only one parameter is modified. In the upper pulse sequence, the duty factor is incremented after each pulse sequence or period, wherein the frequency remains constant. In the lower pulse sequence, a fixed duty factor, for example 50%, is used, wherein the frequency is adapted after each pulse sequence or period. In this example, the frequency is reduced after an elevated starting frequency, wherein the frequency is then approximated to the resonant frequency.

[0059] FIG. 6 makes use of three short pulses as a simpler variation for induction heating coil I1 above, and a pulse sequence of three pulses which are more than twice as long for induction heating coil I2 below, wherein the time intervals between the individual longer pulses are shorter. Overall, however, the lower pulse sequence lasts somewhat longer than the upper pulse sequence. Another pulse sequence is thus used above for induction heating coil I1 than for induction heating coil I2, for example with the meaning of a duty factor of 25% in the upper pulse sequence and 50% in the lower pulse sequence, in each case at identical frequency.

[0060] In FIG. 7, the pulse duration and time interval between the pulses in each pulse sequence are varied. A frequency of 70 kHz can accordingly be used above for induction heating coil I1 and a frequency of 60 kHz below for induction heating coil I2, wherein the same duty factor overall is used above and below. The two pulse sequences above and below can have a time offset from one another, as is shown here. This need not be the case, however, and they can also be started simultaneously.

[0061] In FIG. 8, the pulse count of the two pulse sequences is varied. Three short pulses with a short time interval between one another are used for the upper induction heating coil I1. Four short pulses with a short time interval between one another are used for the lower induction heating coil I2, wherein the pulse duration and time interval between one another corresponds to the upper pulse sequence. The duty factor and frequency may here advantageously remain identical.

[0062] In the exemplary embodiments of FIGS. 9 to 11, the parameters within a pulse sequence are varied in order to code a position of the induction heating coil in an above-stated coordinate system of the induction heating coil within the induction cooktop. The information can be encoded either by means of frequency at an identical duty factor, see FIGS. 9 and 10, or by means of the duty factor at an identical frequency, see FIG. 11.

[0063] The value x or y as an index for determining an arrangement in the coordinate system can accordingly be derived from the signal. It should be noted here that whole pulses are always output, wherein it is, however, possible to adapt the number depending on the frequency. Accordingly in FIG. 9 the index 1 corresponding to the value y has 3 pulses, and in FIG. 10 it has only 2 pulses. As a function of the duty factor, the value x or y may represent a plurality of bits, depending on the number of frequencies used. The number of transferred indices, which may be a plurality of bits, may be modified as a function of data to be transferred and the duty factor. In FIGS. 9 and 10 there are accordingly in each case 3 indices and in FIG. 11 there are only 2 indices. It should be noted here that a duty factor of 0% can also be selected for the second value, the value y in the example here, whereby amplitude shift keying, i.e. a digital type of modulation, is achieved. The amplitude of the carrier is here modified in order to transfer different values.