EP2543233B1 - Hob having at least one cooking zone and method for operating a hob - Google Patents

Description

The invention relates to a hob with at least one cooking zone and a device for detecting a preparation vessel on the cooking zone. Furthermore, the invention relates to a method for operating a hob.

Hobs are known from the prior art, which have several cooking zones. Each cooking zone considered by itself is heated by a radiator, which is located under a mounting plate of the hob, can be placed on the preparation vessels. In this context, hobs are known in which a cooking zone by a plurality of heating units extending into each other, which are formed for example as a circular heating coils or induction coils, are heated. As a result, the cooking zone can be heated over an individual area with heating elements formed in one another and with a different radius.

Especially with regard to an individual activation and deactivation of such separate heating units, the detection of a pot occupancy is essential. As a result, it can be recognized at which position and with which surface size a preparation vessel is set up on the mounting plate.

From the EP 1 768 258 A2 a circuit arrangement for evaluating a sensor state is known, by means of which a corresponding pot occupancy is detectable on a hob.

The known cooking zones of a hob are limited in terms of their size and beyond functionally limited in terms of the arrangement of the heating units and their individual operation.

From the WO 2006/092179 A1 a heating device for a Induktionsgargerät is known. This comprises a circuit arrangement with a plurality of inductors, which can be interconnected differently. The heater includes at least a first resonant circuit comprising at least a first and a second inductor for transmitting heat energy to a member to be heated and a first circuit for exciting the first resonant circuit and for supplying the heating energy to the inductors. Furthermore, the heating device has a switching means by which the heating energy can optionally be supplied in parallel only to one of the inductors or simultaneously to both inductors.

An induction hob, for example, from the document US 2005/0127065 A1 known. Here, two inductors are connected in parallel, with the parallel connection of the inductors being connected in series with a current detector.

The EP 2 068 598 A1 describes an induction hob with a total of four groups of inductors, wherein within the respective group, the inductors are electrically connected in series with each other. The different groups of inductors are each driven with an associated driver circuit or supplied with electrical energy.

An induction hob is further from the document US 2007/0125771 A1 known. Furthermore, the disclosure EP 0 724 379 A1 a control device, in particular for an induction hob with a plurality of heating elements.

It is an object of the present invention to provide an induction hob and a method for operating such an induction hob, by means of which a large-scale cooking zone can be operated energy-efficiently and in a better way, a pot assignment can be performed.

This object is achieved by an induction hob and a method according to the independent claims.

An induction hob according to the invention comprises a circuit arrangement for operating a cooking zone of the induction hob. The circuit arrangement comprises a parallel circuit in which two inductors are connected in parallel. In series with the parallel circuit, a current measuring element is connected. The induction hob includes In addition, a device for occupancy detection of at least a partial cooking zone of the entire cooking zone with a preparation vessel. This device for Occupancy detection includes the current measuring element. By such a design of the induction hob, on the one hand, a more energy-efficient operation can be made possible. In particular, a component-reduced and simplified circuit concept is made possible by such an embodiment, since only a single current measuring element is required for a plurality of inductors in order to be able to detect an occupation of the partial cooking zone that can be heated by the respective inductors. This also allows a very specific approach to the pot assignment recognition.

It is envisaged that the cooking zone can be heated by at least three inductors arranged side by side and two inductors can be supplied with electrical energy with a first driver circuit and the at least third inductor can be supplied with energy with a separate second driver circuit, wherein an inductor depends on a detection of a Preparation vessel is activated on the cooking zone via this inductor. The inductors connected to the first driver circuit can be independently activated and deactivated.

With regard to the formulation of a heatability of a cooking zone with an inductor, it should be noted that this includes that a corresponding heating of the preparation vessel is generated by the electromagnetic interaction of a coil of the inductor with a suitable metallic material of a preparation vessel. Exactly this specific physical basis is understood in the context of the invention by the formulation of the heatability of a cooking zone or a surface thereof or a Teilkochzone with an inductor also below.

In addition, the formulation of a juxtaposition of the inductors is understood to mean such a positioning in which the inductors are positioned side by side to each other. It should therefore be understood an arrangement in which the surfaces formed by the inductors on the cooktop panel arranged above are arranged side by side and do not partially overlap or even a surface is completely absorbed by the other. This would be the case with inductors of different radius, which are arranged radially inside one another, which should not be included here.

According to the invention, the induction hob is also designed with a circuit arrangement which has two separate driver circuits, wherein the at least three heating units in the form of the inductors are operated and supplied with energy by the two driver circuits. As a result of this refinement, the at least three inductors are also functionally assigned to these two driver circuits and are correspondingly supplied with individual power. On the one hand, a particularly large cooking zone can be created by this concept, since the inductors are not in each other but positioned side by side, and moreover, the number is at least three inductors so large that a particularly large heatable surface can be generated.
Moreover, it is ensured by the induction hob according to the invention and the specific circuit concept that not all inductors have to be activated at the same time, whereby energy is saved since surfaces which are not unnecessarily heated are heated to which there is, in principle, no Preparation vessel is set up. By the induction hob, a particularly large cooking zone can be created in this preferred embodiment, which, however, in a specific manner is operable so that again only individual Teilkochzonen, which in turn may be formed of sub-zones, activated and heated as needed, this depends on the respective occupancy by a preparation vessel. On the one hand, it is thus ensured that, in the case of particularly large preparation vessels, a correspondingly large cooking zone is present, which can be heated uniformly over the entire surface, so that even the very large preparation vessel can be uniformly heated. If, however, a smaller preparation vessel is set up on this large cooking zone, it is also recognized by the circuitry principle and the device for detecting a zone occupancy that only a small area is occupied on this large cooking zone, whereby this small area can then be heated individually.

Preferably, a fourth inductor is provided adjacent to the three inductors associated with the cooking zone and which is further energized by the second driver circuit. In particular, two driver circuits are thus provided, which are each assigned two inductors for power supply. Thus, the surface design of the cooking zone and the individual electronic mode of operation can be particularly adapted and coordinated. Thus, the entire cooking zone can be formed in a specific operating mode of the induction hob of two Teilkochzonen. Each of these two partial cooking zones preferably each again comprises at least two subzones. Each of these subzones can be heated in particular by an inductor. Thus, it is provided in particular that the two inductors of the subzones of the first partial cooking zone can be supplied with energy by the first driver circuit and the two inductors of the subzones of the second partial cooking zone can be supplied with energy by the second driver circuit.

It is preferably provided that an inductor, in particular all inductors, of the cooking zone each have or have a single coil. It is therefore not provided in this embodiment, that each heating unit in the form of an inductor has a plurality of coils formed in each other, which are then separately activated and deactivated, but that only a single coil is provided, which is then activated and deactivated. It allows circuitry a relatively simple and robust Design. In addition, in this context, the entire surface can be heated evenly with the heating unit.

Preferably, the heating units are wound in an oval shape with regard to their winding shape, so that the cooking zone comprises at least three, in particular four, adjacent to one another and directly adjoining oval lower zones. By this specific shaping a particularly uniformly large-area coverage and thus heating of the entire cooking zone surface can be achieved. This leads to particularly accentuated cooking results.

Preferably, the first driver circuit has a half-bridge which is electrically connected in series with two relays connected in parallel. It is therefore provided in particular that a first half-bridge circuit of the first driver circuit is connected to a first signal path in which the first relay and the first heating unit are connected. This first circuit path is connected in parallel to a second circuit path in which a second relay and the second heating unit are connected.

In a corresponding embodiment, the second driver circuit is designed, which also has a half-bridge circuit in series with a parallel circuit, in which case the parallel circuit in each case has a circuit path with a relay and connected in series to a heating unit.

By this configuration, a circuitry relatively simple concept can be provided, which also particularly in connection with the device for detecting a preparation vessel on the cooking zone can be particularly simple and reliable to recognize the occupancy of specific areas of the cooking zone with a preparation vessel. In particular, very specific drainage strategies for detecting occupied partial areas of the cooking zone can take place by means of such a circuit design. Especially with such large cooking zones, it is therefore also essential to enable a particularly effective and targeted search strategy with regard to which areas of this large cooking zone are occupied. This is also ensured and supported particularly advantageous by the circuit principle. According to the invention, the heating units connected to the first driver circuit can be activated and deactivated independently of one another. As a result, heating units associated with a driver circuit and functionally connected to this driver circuit for the power supply can be separately activated and deactivated, which makes it possible to heat cooking zone surfaces in a particularly flexible and variable manner.
Preferably, the total area of the cooking zone with at least three heating units is greater than half the depth of the top plate of the hob and / or greater than or equal to half the width of the mounting plate.
Furthermore, the invention relates to a method for operating a cooking zone of the induction hob, which is formed from at least two Teilkochzonen and each Teilkochzone can be heated by an associated inductor, wherein the inductors are connected in parallel in parallel. A current measuring element is connected in series with the parallel circuit and, depending on the current values of the current-measuring element, an occupancy of a partial cooking zone with a preparation vessel is detected. By such a method can be made possible by a very component-reduced circuit reliably and safely a pot detection.
A multi-level search procedure is carried out for occupancy detection of the entire cooking zone. By such a procedure, the occupancy of partial cooking zones is detected with a preparation vessel in a particularly precise and accurate form. This according to the present invention, precisely because the cooking zone is formed of several Teilkochzonen and thus can be accurately determined on which of the Teilkochzonen is a preparation vessel. This multi-stage search process can thus improve the precise local occupancy detection on the cooking zone. This results in an improved operating behavior, as the more precise detection can also make a more precise statement as to which inductors have to be activated for heating the specifically occupied partial cooking zone. This also results in a more energy efficient operation of the hob. According to the invention, in each case one switching element is connected in series to each inductor in the parallel circuit, and in a first search step of the search process, a closing of both switching elements is performed for occupancy detection on the entire cooking zone. Depending on the current value at the current measuring element, a basic occupation of the cooking zone with one or more preparation vessels is detected, this being detected regardless of the exact location at which the preparation vessel is located on the cooking zone. Thus, in a first step, it is at first only ascertained whether there is a preparation vessel at all on the cooking zone, in which connection the exact local position of the preparation vessel is not yet determined. By such a procedure can thus in principle very quickly be detected whether a preparation vessel is set up.
If such a detection of a preparation vessel is detected somewhere on the cooking zone, the switching element remains closed in series with a first inductor in a further subsequent search step. The switching element in series with the second inductor is then opened. Depending on the current value at the current measuring element, it is then detected whether the first partial cooking zone is occupied by a preparation vessel. In a further subsequent search step, the switching element is then opened in series with the first inductor and the switching element is closed in series with the second inductor. Again, it is then detected depending on the current value at the current measuring element, if the second part cooking zone is occupied by a preparation vessel. These specific search steps then identify in a very precise manner where a preparation vessel is positioned precisely on the cooking zone. Preferably, after the occupancy detection, the one or more inductors are supplied with energy, on whose associated partial cooking zone or on the associated partial cooking zones an occupancy with a preparation vessel has been detected. In this connection, the switching elements connected in series with the respective inductors are then closed in the parallel circuit. As a result, the power supply of the inductors can be made possible.
According to the invention, the hob is designed such that the one cooking zone can be heated by at least three inductors arranged side by side. Two inductors are supplied with electrical energy by a first driver circuit. The at least third inductor can be powered by a separate second driver circuit and is not connected to the first driver circuit and can not be powered by the first driver circuit. An inductor is activated depending on detection of a cooking vessel on the cooking zone at a locally specific position via the driver circuit. In this regard, a very specific operating method of a cooking zone of a cooking field designed specifically for this purpose is made possible, so that a particularly large cooking zone can be operated in a particularly effective manner with regard to its areal design. In addition, individually and variably the individual adjacently formed inductors can be activated and deactivated.

Preferably, to detect an occupancy of a cooking zone area with a preparation vessel, an occupancy of the entire first zone area which can be heated by the first two heating units is checked independently of a specific occupancy of a first subzone heatable by the first heating unit and a second subzone heatable by the second heating unit. The approach to the detection of occupancy of the cooking zone with a preparation vessel is done in an efficient manner in view of the explicit size of the cooking zone in a strategic manner with different procedures and process steps to be performed. This requires according to the preferred embodiment, in a first step, a process operation in which not already the majority of the individual heating units with respect to the occupancy arranged thereon, but that in a higher search strategy initially associated with a driver circuit heating units and the entire area heated, namely the first zone area, in general, will be examined for occupancy. Thus, in this first step, there is not already a detailed search as to whether a preparation vessel is installed on a single heating unit or on a surface of the cooking zone above each individual heating unit. Thereby, the process for occupancy detection of the cooking zone can be done faster and more accurate.

In particular, it is then checked in a recognition of occupancy of the first zone area with a preparation vessel on which sub-zone the preparation vessel is arranged and depending on the then for the heating of the activated with the preparation vessel surface most suitable heating unit with the first driver circuit. According to this advantageous embodiment, if, for example, it is detected that a preparation vessel is placed somewhere on the first zone surface, this is detected. In a further step, the further exact occupancy is then checked as to which subzone of this first zone area the preparation vessel is arranged. So only then, if in a general sub-zone of the entire cooking zone, namely the first zone area a preparation vessel is detected, then in a further step checks in detail where the preparation vessel is located exactly in this first zone area. Subsequently, this is then detected and the most suitable heating unit activated, which means that the respective heating unit of the first two heating units, which are provided for heating the first zone areas, is activated, on which then the preparation vessel is actually. If the vessel is located on both heating units which are assigned to the first driver circuit, then both heating units are activated. If the vessel is only located on one of the two heating units, only it is activated by the driver circuit and the other heating unit is deactivated by the first driver circuit.

In a corresponding embodiment, this also applies to the at least third heating unit and the second driver circuit, wherein in an advantageous embodiment this applies analogously to the explanation of the first driver circuit with the first heating units, if the second driver circuit also supplies two separate heating units with energy.

Preferably, to detect occupancy of a cooking zone area with a preparation vessel, an occupancy check of the entire second zone area which can be heated by the heating units connected to the second driver circuit is carried out simultaneously with the occupancy test for the first zone area.

As a result, a particularly efficient and rapid occupancy testing of the entire cooking zone can be carried out and, in particular, if this occupancy check method, as explained above, is a multi-stage process which progressively examines the entire cooking zone area in the first general steps and checks of the larger zone areas recognized thereon preparation unit is detected.

Preferably, with the additional installation of a second preparation vessel onto the cooking zone, a further occupancy testing process is started next to a first preparation vessel that has already been set up and can be heated with at least one activated heating unit. It can therefore, if already a preparation process is running and at least one heating unit is activated by the functionally associated driver circuit, also in the wake of at least another preparation vessel are placed on this cooking zone and then there is another Belegungsprüfungsvorgang. The already activated heating unit remains in the active state and in particular the remaining areas of the cooking zone that are not occupied in the first occupancy check process are checked for occupancy. This is done in particular according to the above graded occupancy test method.

The further occupancy checking process is preferably started by the user by actuating an operating element. Unwanted activations of heating units can be prevented, so that no safety-critical operating conditions occur.

In particular, therefore, a method is provided in which a relatively large cooking zone having at least three juxtaposed heating units, which are operated by at least two separate driver circuits, carried out a stepped occupancy testing method and is recognized depending on which heating units in a particularly efficient manner must be activated in order to heat the occupied areas. For this purpose, a division of the cooking zone into such zone surfaces is generally carried out in the first place, which can be heated by the heating units connected to the separate driver circuits. Only then, if an occupancy is detected on one of these zone areas, is then further searched on this zone area, which subzone of this zone area is actually occupied by a preparation vessel. If this sub-zone is then detected, the most suitable heating unit for this heating of this sub-zone is activated.

In particular, it is provided that with regard to a first method step, depending on the existing number of driver circuits, the cooking zone area is divided into a corresponding equal number of zone areas regardless of how many heating units each of these zone areas is heated. Thus, superordinate and independent of the number of heating units per zone area, it is thus first checked in a method step whether preparation vessels are placed on one or more of these zone areas. Only then, when it is detected on a zone surface that a preparation vessel is placed on it, then in a further process step then checked more precisely within this zone area, where this preparation vessel is actually located locally. For this purpose, those heating units which can heat this zone area are then checked with regard to their local positions of the subzones which can be heated for a respective occupation with the preparation vessel, this being carried out successively, in particular in chronological order.
In particular, searching in the zone areas of the entire cooking zone area is performed simultaneously.
Advantageous embodiments of the hob according to the invention are to be regarded as advantageous embodiments of the method according to the invention.
Further features of the invention will become apparent from the claims, the figures and the description of the figures.

Fig. 1

eine schematische Draufsichtdarstellung auf ein Ausführungsbeispiel eines erfindungsgemäßen Kochfelds; und

Fig. 2

eine schematische vereinfachte Darstellung eines Schaltungsprinzips des Kochfelds gemäß Fig. 1.

Embodiments of the invention are explained in more detail below with reference to schematic drawings. Show it:

Fig. 1

a schematic plan view of an embodiment of a hob according to the invention; and

Fig. 2

a schematic simplified representation of a circuit principle of the hob according to Fig. 1 ,

In the figures, identical or functionally identical elements are provided with the same reference numerals.

In Fig. 1 is shown in a schematic representation of a plan view of a hob 1, which has a mounting plate 2, which may be formed of glass or glass ceramic. On a top 3 of the mounting plate 2 preparation vessels, such as pans, pots or the like can be placed. The hob 1 in the exemplary embodiment comprises three cooking zones 4, 5 and 6, which are different in terms of their surface dimensions and their surface shape. Thus, the cooking zones 4 and 5 are circular and have different radii. By means of the contours 41 and 51 of the cooking zones 4 and 5, the maximum area size is indicated, which is thus recognizable to a user, where below the storage tray 2 in these positions for the cooking zones 4 and 5 is a radiator.

The hob 1 is formed in the embodiment as an induction hob, so that under the cooking zones 4 and 5 each have at least one inductor is formed. In the embodiment it is provided that each of these inductors has a single coil, which is wound in a corresponding circular, so that upon activation of the induction coil substantially the entire surface of the cooking zone 4, which is bounded by the contour 41, is heated, and in view of Cooking zone 5 which is limited by the contour 51, this is also heated by an induction coil. As in the illustration according to Fig. 1 can be seen, the cooking zones 4 and 5 are arranged spaced from each other, wherein they are also spaced apart from the cooking zone 6 are arranged.

It can also be provided that at least one of the cooking zones 4 and 5 comprise a plurality of induction coils, which are separately activatable and deactivatable and are formed as circles arranged inside each other, so that these independent induction coils have different radii. As a result, a cooking zone 4 and 5 can also be heated in radially smaller and larger surface areas.

In addition, the cooking zone 6 is formed as a particularly large cooking zone area, which is also formed rectangular in terms of their shape beyond. In the embodiment shown, the cooking zone 6 comprises four inductors arranged below the mounting plate 2, of which each inductor has a single induction coil. With regard to the shape of these are arranged side by side and have an oval shape, as in Fig. 1 is shown. The inductors adjoin one another in such a way that the heatable surface can be heated almost completely. Owing to the oval shape of the wound induction coils of the individual inductors 6a, 6b, 6c and 6d designed as heating units, particularly uniform surface heating is possible. As can be seen, these inductors 6a to 6d with their induction coils are not arranged in cascade with one another, but next to each other and all have the same geometric dimensions.

In addition, the hob 1 comprises a device 16 for detecting a preparation vessel on the cooking zones 4, 5 and 6. In particular, this is to be seen with regard to the recognition of a preparation vessel on the cooking zone 6, which in terms of area very large and larger than the surfaces of the cooking zone 4 and 5 together.

In particular, the surface of the cooking zone 6 extends substantially over at least 80%, preferably at least 90% of the depth of the hob 1 and thus also the mounting plate 2, which means an extension in the y-direction. In addition, the cooking zone 6 has a surface in the width (x-direction), which in the embodiment comprises at least 30%, preferably 40% of the total width extension of the mounting plate 2.

The device 16 preferably comprises a plurality of sensors, which are capacitive or inductive working, so that the occupancy can be reliably detected.

The hob 1 further comprises a circuit arrangement 7, which is designed to supply power to the individual heating units of the cooking zones 4 to 6, and the inductors 6a to 6d comprises. In this context, the circuit arrangement comprises a first driver circuit 8 and a separate second driver circuit 9 for this purpose. The first driver circuit 8 is used to supply the two first heating units or inductors 6a and 6b formed. In addition, the second drive circuit 9 is designed to supply power to the two further heating units or inductors 6c and 6d. The two driver circuits 8 and 9 are independently operable.

In addition, the hob 1 comprises a control unit, which is associated with the circuit arrangement 7 component-specific and functional. By means of the control unit, the individual inductors 6a to 6d are individually controlled and activated and deactivated accordingly, and the signals of the device 16 can be correspondingly processed with this control unit.

With regard to the specific structure of the circuit arrangement 7, reference is made to the simplified circuit diagram in FIG Fig. 2 directed. Via a power supply network 19 AC voltage for the circuit 7 is provided. The first driver circuit 8 comprises a first half-bridge circuit 10, which is connected in series with a parallel circuit 20. The parallel circuit 20 comprises a first circuit branch in which a first relay 11 is connected in series with the induction coil of the inductor 6a and thus the first heating unit. In parallel to the second circuit branch, a relay 12 is also connected, which is connected in series with the induction coil of the second inductor 6b and the second heating unit.

In addition, the second driver circuit 9 is constructed analogously to the first driver circuit 8 and also comprises a half-bridge circuit 13 which is connected in series with a parallel circuit. Here, too, this parallel circuit comprises a first circuit branch in which a relay 14 is connected in series with an induction coil of the third inductor 6c or the third heating unit. In a second circuit branch, another relay 15 is connected in series with an induction coil of the fourth inductor 6d and the fourth heating unit, respectively. These sub-zones 61a and 61b essentially represent in terms of area the size of the oval configurations of the induction coils arranged underneath, which are characterized by the corresponding contours on the upper side 3 of the mounting plate 2.

In addition, the second driver circuit 9 is constructed analogously to the first driver circuit 8 and also comprises a half-bridge circuit 13 connected in series with one another Parallel circuit 21 is connected. This parallel circuit 21 also here comprises a first circuit branch in which a relay 14 is connected in series with an induction coil of the third inductor 6c or the third heating unit. In a second circuit branch, another relay 15 is connected in series with an induction coil of the fourth inductor 6d and the fourth heating unit, respectively.

In series with the parallel circuit 20, a current measuring element 22 is connected. Thus, a circuit concept is realized in which in the first driver circuit 8, only such a current measuring element 22 is present, which is not connected in the parallel circuit 20 itself but in series with the parallel circuit 20. A very component-reduced design can be created thereby. The current measuring element 22 is component-specific also associated with the device 16 for pot detection or occupancy detection of the cooking zone. In an analogous manner, the second driver circuit 9 also has a current measuring element 23, which is connected in series with the parallel circuit 21.

In the exemplary embodiment, the current measuring elements 22 and 23 of the separate driver circuits 8 and 9 are connected between the half-bridge circuits 10 and 13 and the parallel circuits 20 and 21, respectively.

As in the illustration according to Fig. 2 indicated, the current measuring element 22 could be connected in series with the parallel circuit 20 even after the parallel circuit 20, as the dashed box symbolizes. Similarly, the interconnection of the current measuring element 23 could be provided after the parallel circuit 21 and in series.

As shown in Fig. 1 In the exemplary embodiment, the induction hob 1 also includes an operating device 24, which is formed on the hob plate or mounting plate 2.

This operating device 24 may be formed at least partially touch-sensitive. It can have a plurality of operating elements and, moreover, also comprise a display unit. In particular, the operating device 24 has an operating element 25, which may also be formed touch-sensitive. With this control element 25 For example, a user-defined activation of an occupancy recognition test of the entire cooking zone 6 can be carried out.

As already explained at the beginning, the large-area cooking zone 6 is formed from several partial cooking zones. In the exemplary embodiment, two partial cooking zones 61 and 62 are provided, whose corresponding zone areas are identified. These are contiguous and immediately adjacent to each other. Each of these partial cooking zones 61 and 62 has in the exemplary embodiment two sub-zones 61a and 61b and 62a and 62b. The areas of the subzones are defined in terms of size by the coils of the inductors 6a to 6d, which are wound in an oval fashion, or their size.

With regard to the immediate juxtaposition of the partial cooking zones 61 and 62 and the subzones 61 a, 61 b, 62 a and 62 b, this is to be provided according to the illustration in that the surfaces defined by the respective contours are arranged without overlapping one another.

The induction hob 1 is designed so that at least the cooking zone 6 can be operated in two different operating modes. Thus, it is provided in a first operating mode that the two partial cooking zones 61 and 62, which form the entire cooking zone 6, are operated together and thus form the entire cooking surface of the cooking zone 6. In this first operating mode, provision is made in particular for all partial cooking zones 61 and 62 and in particular also the subzones 61 a, 61 b, 62 a and 62 b to be supplied with the same electrical power. In operation, this relates to the partial cooking zones 61 and 62 occupied by a preparation vessel 17 or 18 and the subzones 61 a, 61 b, 62 a and 62 b formed. It is thus provided that the subzones 61 a, 61 b, 62 a and 62 b respectively locally and functionally associated inductors 6 a to 6 d can be fed only with the same power when this first mode of operation is activated. This means that those inductors 6a to 6d, their associated sub-zones 61a, 61b, 62a and 62b or the corresponding Teilkochzonen 61 and 62 on the mounting plate 2, which are covered with a preparation vessel 17 or 18, only with the same electrical Power can be fed.

In this first mode of operation, an occupancy recognition test is performed by means of the device 16, as will be explained later. in the Embodiment is provided that upon activation of the hob 1 and a user-defined or automatically started first operating mode of the cooking zone 6, a first occupancy detection test is performed automatically. If a preparation vessel 17 or 18 is then detected at specific locations, the inductors 6a to 6d which are correspondingly occupied via the subzones 61a, 61b, 62a and 62b are activated. If a further occupancy check is subsequently required or is to be carried out, this can only be started user-defined. For this purpose, the user must press the control element 25. An automatic second occupancy detection test and thus starting a second occupancy detection phase automatically is therefore not possible.

The cooking zone 6 is also operable in its second mode of operation by allowing the partial cooking zones 61 and 62 to be independently switched on and off. In this second operating mode, the partial cooking zones 61 and 62 can also be operated independently of one another with different powers. In this second operating mode quasi an entire cooking zone 6 does not exist and the partial cooking zones 61 and 62 are to be seen as separate autonomous cooking zones analogous to the other cooking zones 4 and 5.

With regard to the procedure during operation of the hob 1 and in particular of the large-area cooking zone 6 in said first operating mode, a multi-stage search method is performed with regard to the occupancy detection process-specific. For this purpose, it is checked in a first step, if ever a preparation vessel is arranged on the entire cooking zone 6, which is searched in this first search step only superordinate and not local specific for an occupancy.

The partial cooking zones 61 and 62 with their zone areas shown accordingly are preferably formed with regard to the number and their size depending on the number of driver circuits 8 and 9. In the exemplary embodiment, the first partial cooking zone 61 is thus formed such that it represents approximately half of the entire cooking zone surface of the cooking zone 6 and in particular includes the surfaces of the regions of the cooking zone 6, which can be heated with the two first inductors 6a and 6b. In an analogous manner, the second partial cooking zone 62 is formed such that it the area of the cooking zone 6 comprises, through which the further inductors 6c and 6d can be heated.

According to the first search step, a general occupancy of the cooking zone 6 is thus first checked in a general and higher-order search strategy. With regard to this detection, low-voltage measuring signals are generated by the device 16, which generate an oscillation in one of the series resonant circuits formed by the inductors 6a to 6d and the indicated capacitors. In this first search step, all switching elements in the form of relays 11 to 15 are closed. By the current measuring elements 22 and 23 then correspondingly occurring current values are detected, it being possible to detect, depending on the current values, whether at least one preparation vessel is located on the cooking zone 6.

If it is found in this first step that at least one preparation vessel is located on the cooking zone 6, then in a further subsequent search step a locally precise search, where the preparation vessel is exactly, is carried out.

Due to the in Fig. 2 1, in which only one current measuring element 22 or 23 is assigned to one of the driver circuits 8 and 9 and these are connected in series to the parallel circuits 20 and 21 in a specific manner, a further search strategy is to be carried out in a specific manner in this respect.

For this purpose, it is then initially provided that the relay 11 and the relay 14 remain closed, whereas the relay 12 and the relay 15 are opened. By this procedure, it can be detected via the current measuring elements 22 and 23 whether a preparation vessel is arranged above the inductor 6a and the inductor 6c and the corresponding sub-zone 61a or 62a is occupied.

In a further search step, the relays 11 and 14 are then opened and the relays 12 and 15 are closed. Depending on the then again detected current values via the current measuring elements 22 and 23, it can also be detected here whether there are preparation vessels above the subzones 61 b and 62 b.

It may of course also be provided that initially the relays 11 and 14 are opened and the relays 12 and 15 remain closed and subsequently the relays 11 and 14 are closed and the relays 12 and 15 are opened in the following.

Depending on these further search steps carried out, it is then determined exactly at which locally specific positions of the entire cooking zone 6 there is actually a preparation vessel.

Subsequently, only that inductor 6a to 6b is then supplied with electrical energy by closing the series-connected relays 11 to 15, whose associated sub-zone 61a, 61b, 62a and 62b is also explicitly occupied with a preparation vessel.

The remaining inductors, whose associated subzones are not occupied, are or will remain deactivated.

Such occupancy detection phase takes in the embodiment about 5 seconds. During this period, preparation vessels 17 and 18 can be removed or placed, and this is then also recognized. If an occupancy recognition phase has expired and ended accordingly, an additional installation of a preparation vessel on the cooking zone 6 will not be detected in the further course, and this further preparation vessel will then not be heated either. Only when the user actively activates the control element 25, a further occupancy detection test is started and then detected the additionally prepared after the first occupancy detection phase preparation vessel.

It should also be mentioned that a cooking vessel detected during an occupancy detection phase can be displaced (but not removed) on the cooking zone 6 in this first operating mode after expiration of the occupancy detection phase on the cooking zone 6, and this displacement is detected. Then, those inductors 6a to 6d are activated which are required for heating the preparation vessel at the new location, whereby those inducers 6a to 6d, which are now not occupied compared to the original position of the preparation vessel before the displacement, are deactivated.

In the exemplary illustration according to Fig. 1 two preparation vessels 17 and 18 are shown, which are each smaller in size than a partial cooking zone 61 or 62. Particularly advantageous is the first operating mode of the hob 1, when a preparation vessel is placed on the cooking zone 6, which is larger in area than a Teilkochzone 61 or 62. For exactly then this first mode of operation is particularly advantageous because virtually in the second mode of operation, a total heating of such a large preparation vessel is not possible.

The sub-zones 61 a, 61 b, 62 a and 62 b shown by way of example are the same in terms of surface area in terms of area and also the same in terms of their shape. It can also be provided that at least one sub-zone is larger and / or formed with a different shape. This also depends in particular on the design and size of the inductor 6a to 6d arranged underneath and associated therewith.

The above explanation of the multi-stage search method can be found in the in Fig. 2 The specific embodiment shown are also carried out to the effect that after the basic principle first detection of a preparation vessel somewhere on the cooking zone 6, the subsequent search steps in the sub-areas concerning the Teilkochzone 61 and the Teilkochzone 62 not simultaneously, as explained above, but with a time delay.

With regard to the exemplary representation in Fig. 1 the relay 13 is opened because no preparation vessel is placed on the sub-zone 62a. The further sub-zones 61 a, 61 b and 62 b are covered with the preparation vessels 17 and 18, so that the associated underneath and thus below the cooktop plate or mounting plate 2 arranged inductors 6 a, 6 b and 6 d must be supplied with energy, including the relay 11 , 12 and 15 are closed.

LIST OF REFERENCE NUMBERS

1

hob

2

mounting plate

3

top

4, 5, 6

cooking zones

41, 51

contours

6a, 6b, 6c, 6d

inducers

7

circuitry

8, 9

driver circuits

10, 13

Half-bridge circuits

11, 12, 14, 15

relay

16

contraption

17, 18

preparation vessels

61

first partial cooking zone

61 a, 61 b

subzones

62

second partial cooking zone

62a, 62b

subzones

Claims (7)

1. Induction cooktop having a circuit arrangement (7) for operating a cooking zone (6) of the induction cooktop (1), which has a parallel circuit (20, 21), in which two inductors (6a to 6d) are connected in a parallel manner, wherein a current measuring element (22, 23) is connected in series to the parallel circuit (20, 21) and an apparatus (16) is configured to detect occupancy of at least one cooking sub-zone (61, 62) of the cooking zone (6) by a food preparation vessel (17, 18), said apparatus (16) featuring the current measuring element (22, 23), wherein the cooking zone (6) is able to be heated by at least three adjacently disposed inductors (6a to 6d) and two inductors (6a to 6d) are able to be supplied with electrical energy with a first driver circuit (8, 9), wherein the inductors (6a to 6d) connected to the first driver circuit (8, 9) can be activated and deactivated independently of one another, characterised in that the at least third inductor (6a to 6d) is able to be supplied with energy with a separate second driver circuit (8, 9), wherein the induction cooktop (1) is able to be operated in a first operating mode, in which the cooking sub-zones (61, 62) are operated together and thus form an overall cooking surface of the cooking zone (6), wherein all cooking sub-zones (61, 62) are supplied with the same the electrical power and an inductor (6a to 6d) is able to be activated as a function of detection of a food preparation vessel (17, 18) on the cooking zone (6) by way of said inductor (6), wherein the apparatus (16) for occupancy detection is configured to perform a multistage search method to detect occupancy of the overall cooking zone (6).
2. Induction cooktop according to claim 1, characterised in that a fourth inductor (6a to 6d) is supplied with energy by the second driver circuit (8, 9).
3. Method for operating a cooking zone (6) of an induction cooktop (1), which is formed from at least two cooking sub-zones (61, 62), and each cooking sub-zone (61, 62) is able to be heated by an assigned inductor (6a to 6d), the inductors (6a to 6d) being connected in a parallel manner in a parallel circuit (20, 21), wherein a current measuring element (22, 23) is connected in series to the parallel circuit (20, 21) and occupancy of a cooking sub-zone (61, 62) by a food preparation vessel (17, 18) is detected from current values captured by the current measuring element (22, 23), wherein the cooking zone (6) is heated by at least three adjacently disposed inductors (6a to 6d) and two inductors (6a to 6d) are supplied with electrical energy with a first driver circuit (8, 9), wherein the inductors (6a to 6d) connected to the first driver circuit (8, 9) can be activated and deactivated independently of one another, characterised in that the at least third inductor (6a to 6d) is supplied with energy with a separate second driver circuit (8, 9), wherein the induction cooktop (1) is operated in a first operating mode, in which the cooking sub-zones (61, 62) are operated together and thus form an overall cooking surface of the cooking zone (6), wherein all cooking sub-zones (61, 62) are supplied with the same electrical power and an inductor (6a to 6d) is activated as a function of detection of a food preparation vessel (17, 18) on the cooking zone (6) by way of said inductor (6) and a multistage search method is performed to detect occupancy of the overall cooking zone (6).
4. Method according to claim 3, characterised in that a switching element (11, 12, 14, 15) is connected respectively in series to each inductor (6a to 6d) in the parallel circuit (20, 21) and in a first search step to detect occupancy on the overall cooking zone (6) both switching elements (11, 12, 14, 15) are closed and basic occupancy of the cooking zone (6) by a food preparation vessel (17, 18) is detected from the current value at the current measuring element, independently of the precise location of the food preparation vessel (17, 18) on the cooking zone (6).
5. Method according to claim 4, characterised in that in a further search step the switching element (11, 12, 14, 15) connected in series to the first inductor (6a to 6d) remains closed and the switching element (11, 12, 14, 15) connected in series to the second inductor (6a to 6d) is opened and it is detected from the current value at the current measuring element (22, 23) whether the first cooking sub-zone (61, 62) is occupied by a food preparation vessel (17, 18) and in a further search step the switching element (11, 12, 14, 15) connected in series to the first inductor (6a to 6d) is opened and the switching element (11, 12, 14, 15) connected in series to the second inductor (6a to 6d) is closed and it is detected from the current value at the current measuring element (22, 23) whether the second cooking sub-zone (61, 62) is occupied by a food preparation vessel (17, 18).
6. Method according to claim 5, characterised in that after occupancy detection the inductors (6a to 6d), on the assigned cooking sub-zones (61, 62) of which occupancy was detected, are supplied with energy and to this end the switching elements (11, 12, 14, 15) connected in series to the respective inductors (6a to 6d) are closed.
7. Method according to one of claims 3 to 6, characterised in that the cooktop (1) is configured in such a manner that the one cooking zone (6) is able to be heated by at least three adjacently disposed inductors (6a to 6d) and two inductors (6a to 6d) are able to be supplied with electrical energy with a first driver circuit (8, 9) and the at least third inductor (6a to 6d) is able to be supplied with energy with a separate second driver circuit (8, 9) and an inductor (6a to 6d) is able to be activated as a function of detection of a food preparation vessel (17, 18) on the cooking zone (6) by way of said inductor (6a to 6d).

Images