EP3026981A1 - Induction cooktop and method for controlling an induction cooktop - Google Patents

Abstract

An induction hob has a cooktop panel, a plurality of induction heating coils disposed below the cooktop panel, and a plurality of sensor coils disposed below the cooktop panel. The induction heating coils are rectangular, with at least two induction heating coils arranged one behind the other and at least three induction heating coils next to one another. Two adjacent induction heating coils form a neighboring area with each other, in which both induction heating coils lie with their adjacent sides. At least one sensor coil is arranged in each neighboring area, wherein in a distance direction from one induction heating coil to the adjacent induction heating coil exactly one single sensor coil is provided.

Description

The invention relates to an induction hob and a method for controlling such an induction hob.

With induction hobs, it is technically possible with an induction heating coil per se to determine the presence of a pot above the induction heating coil or on a cooking point defined by the induction heating coil, as long as the pot itself is suitable for inductive heating. In modern induction hobs, for example, according to the EP 2670211 A2 , but it should now be possible through a variety of distributed induction heating coils, not only always cook with exactly one pot on exactly one hob with exactly one induction heating coil. For this purpose, a plurality of significantly smaller induction heating coils is provided, of which, for example, five or seven together with sufficient coverage of a pot together for this pot quasi form a cooking point and heat the pot. However, since it is desired in such an induction hob to be able to set up the pots at any point, it may not be sufficient in adjacent induction heating coils due to the fact that it has been established that a pot has been set up, this as a common thing to operate To consider cooking place and then to apply with common similar performance. That's why the beats EP 2670211 A2 provide additional sensors for pot detection and thereby to arrange a large number of distributed on the induction hob.

Task and solution

The invention has for its object to provide an induction induction hob mentioned above and a process suitable for its control, which can be solved with the problems of the prior art and it is particularly possible, with not too much effort a Aufsetzort a pot on the induction hob recognize and to use for controlling the induction hob or the induction heating coils.

This object is achieved by an induction hob with the features of claim 1 and a method for controlling such an induction hob with the features of claim 13. Advantageous and preferred embodiments of the invention are the subject the further claims and are explained in more detail below. In this case, some of the features are described only for the induction hob or only for the method for its control. However, they should be able to apply independently, however, both for the induction hob and for the process independently. The wording of the claims is incorporated herein by express reference.

It is envisaged that the induction hob has a hob plate and a plurality of induction heating coils, which are arranged below the hob plate. Furthermore, several sensor coils are arranged under the hob plate. These sensor coils work advantageously inductively to discover the presence of a pot over itself.

According to the invention, it is provided that the induction heating coils are rectangular or approximately rectangular. Advantageously, they are slightly elongated, where they are particularly advantageous 10% to a maximum of 50% longer than wide. The approximate rectangular shape comes from the fact that the coil windings can not extend to the very corners or should not be bent. A radius at the corners can therefore be between 1 cm and 3 cm, in some cases even 5 cm. Nevertheless, the shape is substantially rectangular or is considered accordingly. A basically similar rectangular induction heating coil is from the DE 20 2006 016 551 U1 known.

At least two induction heating coils are arranged one behind the other and at least three induction heating coils are arranged side by side. This means that at least six induction heating coils are provided on the induction hob, preferably eight or ten.

Furthermore, according to the invention, two adjacent induction heating coils form a neighboring area with one another, wherein these two induction heating coils then lie with their adjacent sides in this neighboring area. Advantageously, two adjacent induction heating coils have a certain distance from each other, ie a distance between their outermost and their side defining coil turns. This distance between each other can be between 1 cm and 3 cm. In each of these neighboring areas at least one sensor coil is arranged or its center is arranged there, the sensor coil is advantageously also slightly wider than a neighboring area. Furthermore, exactly one single sensor coil is provided in a distance direction from one induction heating coil to the adjacent induction heating coil. In simple terms, this means that, although in this spacing direction only a single sensor coil is provided between the adjacent two induction heating coils, which is advantageously arranged with its center between the two induction heating coils. Along however, two sensor coils may be provided in the region between two adjacent induction heating coils. These two sensor coils can then be provided next to one another, advantageously with the same orientation to the two adjacent induction heating coils.

Thus, it is possible that with a limited number of sensor coils, a flat coverage of the induction hob or the hob plate and thus the cooking area with respect to pots is possible. In addition to the pot detection function by the induction heating coil itself, which has been mentioned at the outset, the individual sensor coils can thus be used to detect the presence of a pot over itself with a relatively fine covering and thus to enable determination in the overall evaluation of all induction heating coils and of all sensor coils. where each pot is placed and how big this is. Because only a single sensor coil is provided in the direction of spacing between two adjacent induction heating coils, but possibly several in the transverse direction to this spacing direction, it can also be achieved that the induction heating coils lie relatively close to one another. So they can form a common cooking place for a common operation for heating a large pot without large gaps between the induction heating coils.

Although more than two sensor coils could be provided next to one another in at least one neighboring area in the transverse direction to the distance direction or along the adjacent sides of the induction heating coils, which form the neighboring area. However, this actually only works if relatively long induction heating coils are used which are at least 50% longer than they are wide.

Advantageously, it is provided that the sensor coils in the spacing direction are arranged so to speak symmetrically or uniformly between the induction heating coils. Thus, a center point of a sensor coil is particularly advantageous not only in the neighboring area of two adjacent induction heating coils, but also between the adjacent sides of the induction heating coils, preferably exactly in the middle between these two adjacent sides.

In an advantageous further embodiment of the invention can be provided that not only between induction heating coils or in adjacent areas of adjacent induction heating coils sensor coils are arranged, but sensor coils are also arranged so that they run largely or completely over an induction heating coil. In this case, these sensor coils are preferably above a central area or a central area of an induction heating coil arranged. These are then due to their considerably smaller design than an induction heating coil not to detect at all the presence of a pot somewhere above the induction heating or their partial or complete coverage with a pot. Rather, it can also be determined, even if the sensor coil is arranged above the central or central region of the induction heating coil, whether a proportionately significant coverage of the induction heating coil with a pot, for example 20% to 30% or even 40%, is present in the middle or not. In the former case, it could then be concluded from this that the significant overlap of the induction heating coil is also present in its center and thus this pot is to be heated, ie the induction coil goes into heating mode. By evaluating further, in particular adjacent, sensor coils, as well as the adjacent induction heating coils, it can then be determined whether this pot is also arranged over further induction heating coils or sufficiently arranged over further induction coils, which then likewise go into heating operation with the same heat output as the former induction heating coil. Similar considerations also apply to the second case. Then, however, it can be assumed that, in order to achieve this high level of overlap, the pot placed over the induction heating coil is a rather large pot, which is then, with even greater probability, also covering one of the adjacent induction heating coils. Then it must be determined whether one of these induction heating coils should also go into heating mode.

In one embodiment of the invention, the induction heating coils can be designed differently, in particular of different sizes. In another advantageous embodiment, all induction heating coils are the same size and / or even identical. This simplifies and reduces production costs. Furthermore, then a surface induction hob can be easily equipped with a number of induction heating coils. Particularly advantageously, all induction heating coils of an induction hob have the same winding direction. Thus, in principle, their mounting orientation is always the same. By the distance between adjacent induction heating coils to each other and by the advantageous use of conventional ferrite cores on the induction heating coils negative effects of mutual interference can be avoided.

While it has been explained in the introduction that two sensor coils can be arranged next to one another along this neighboring area in neighboring areas on two induction heating coils which are adjacent to one another with their long sides, only a single sensor coil should be located in shorter adjacent areas of induction heating coils adjacent to one another with their short sides be arranged. This has become part of the Invention found sufficient for a fine enough resolved determination of the presence of a raised pot. Thus, the component cost can be reduced. In the longer neighboring areas, exactly two sensor coils are advantageously provided.

On the one hand, it is advantageous if the sensor coils are regularly and / or uniformly distributed, in particular with regard to their respective aforementioned orientation to a middle region or central region of induction heating coils and / or in neighboring regions between two adjacent induction heating coils. In the second case, the centers of the sensor coils are advantageously located between two induction heating coils. Furthermore, it can be provided that the sensor coils are arranged on the short sides of the induction heating coils approximately centrally aligned with the short sides. Along the long sides of adjacent induction heating coils it can be provided that the one sensor coil arranged there or the plurality of sensor coils arranged there are displaced toward a central region of the induction hob or away from an outer region or outer edge of the induction hob, for example by 5% to 25% of their actual symmetrical or uniform arrangement. This takes into account that coverage of an induction heating coil in the outer area or near the outer edge of the induction hob is less frequent and, if it occurs, is achieved by a pot, so that detection even further to the outer area is actually not necessary. An operator will hardly arrange a pot partly outwardly projecting beyond the outer area of the induction hob and partially overlapping an induction heating coil from the edge and want this pot to be heated. Only when this takes place so far that a significant proportion of the induction heating coil is covered, for example, by 30% to 50%, and possibly also a sensor coil arranged in a middle region of this induction heating coil should the heating operation take place. Due to the displacement of the sensor coils away from the edge region or towards a central region of the induction hob, the density of the sensor coils and thus the recognition accuracy can be improved there while the number of components remains the same.

In an advantageous embodiment of the invention, it is provided that the sensor coils have a round shape, in particular a circular shape. This is mainly due to the fact that their geometric shape, unlike the induction heating, no essential importance and this round shape allows easy production. For example, a sensor coil may have 10 to 40 turns. Their diameter can be between 1 cm or 2 cm and 5 cm.

The sensor coils preferably extend at least partially above the induction heating coils or are arranged above them, ie in particular they run in a higher plane. The sensor coils may be placed on the induction heating coils, but need not. Advantageously, they are fixed independently of the induction heating coils or not fixed by placing them on the induction heating coils, but on a further carrier device. This further support means is, for example, a flat carrier plate or carrier film, which may be attached to the underside of the hob plate or simply be placed on the other induction hob or its Induktionsheizspulen that form the uppermost region or the top of the base of the induction hob. In addition to a mechanical attachment to such a support means and an electrical contact can be made via this.

The sensor coils arranged centrally or centrally above an induction heating coil can essentially run in a region in which the induction heating coil has no coil turns in its center. The arranged in the neighborhood areas sensor coils overlap the induction heating coils or their edge regions advantageously evenly and similarly. This is mainly because the sensor coils for a good function will preferably be wider than the width of a gap or intermediate region between adjacent induction heating coils.

In an advantageous embodiment of the invention, the induction heating coils can have a single layer of turns or their turns can run in a single layer and thus a single plane. This is advantageous parallel to the hob plate and also parallel to a layer or plane in which the sensor coils run. In a similar form, but in principle also independently, in one alternative, the sensor coils can be wound in one layer or their turns can run in a single layer or a single and advantageously common plane. Also, the sensor coils are advantageously identical to each other formed to reduce component costs. In another alternative, all windings in a sensor coil have approximately the same diameter with deviations from 1 to 5 times a wire thickness. In this case, the windings form a quasi bundle with the smallest possible extent in the vertical direction and also in the diameter of the sensor coil. A disadvantage would be the geometrical extent of the bundle; the higher inductance would be advantageous for a smaller number of turns.

In an embodiment of the invention, a sensor coil or all sensor coils can have or carry a temperature sensor, for example in their middle region or on a center. Sensor coil and temperature sensor can form a unit, advantageously with a single electrical connection, so that they can be easily installed and connected. The temperature sensor is particularly advantageous a temperature-dependent resistor, such as a PT1000. The temperature sensor can be used together with the sensor coil to reliably detect the setting up of a pot above it, for example if no temperature increase takes place despite heating operation of the induction heating coil. Additionally or alternatively, it may be used for normal functions of a temperature sensor such as a hot display.

In an aforementioned method for controlling an aforementioned induction cooktop is provided that the sensor coils are always operated or should detect whether a pot is placed on the cooktop panel above them. This continuous operation should mean here that the sensor coils are not operated every second or permanently, but for example in the interval mode or every few seconds, for example every 0.5 seconds to 30 seconds. However, the operation of an induction heating coil for heating a raised pot should not mean that then the sensor coils no longer have to work. It can be provided that for the sake of simplicity, advantageously in an interval operation, all the sensor coils are operated continuously, that is, for example, capture all the aforementioned 0.5 second to 30 seconds or try to detect whether a pot is placed above them. If a sensor coil is impaired in its function by an induction heating coil operated directly below or adjacent thereto, this does not interfere since it is then possible to start from an attached pot or a pot placed sufficiently on the induction heating coil. Otherwise, the induction heating coil would, due to their own operating conditions, especially in insufficiently placed pot or insufficient coverage, set the heating mode.

Advantageously, the resonant frequency of the sensor coils and their evaluation circuit is well above the operating frequency of the induction coil, preferably 5 times to 30 times higher. In this way, they can each work better and do not bother themselves. Particularly advantageously, an induction coil is only put into operation for heating a pot, provided that at least one of the sensor coils is covered by a pot. Then the presence of a pot is ensured.

Further advantageous aspects relating to a control of the induction hob are described in connection with the figures and can be better explained with reference to the figures.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combinations in an embodiment of the invention and in other fields be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into individual sections as well as intermediate headings does not restrict the general validity of the statements made thereunder.

Brief description of the drawings

Fig. 1

eine Draufsicht auf ein Induktionskochfeld gemäß der Erfindung mit abgenommener Kochfeldplatte und

Fig. 2

eine Ansicht verschiedener Konfigurationen von Töpfen auf dem Induktionskochfeld aus Fig. 1.

Embodiments of the invention are shown schematically in the drawings and are explained in more detail below. In the drawings show:

Fig. 1

a plan view of an induction hob according to the invention with removed hob plate and

Fig. 2

a view of different configurations of pots on the induction hob off Fig. 1 ,

Detailed description of the embodiments

In the Fig. 1 an induction hob 11 according to the invention is shown in plan view, but with removed or without hob plate, so to speak, a substructure 12. This substructure 12 can, as shown here, be connected as usual with a cooktop. For this purpose, the substructure 12 has a support plate 13, which with supports or the like. then just connected to the hob plate.

On the support plate 13 eight substantially rectangular induction heating coils 15a to 15h are arranged. The Induktionsheizspulen 15 are all identical and aligned identically, as can be detected at least in its central region at the discharge of a respective coil winding 19 a to 19 h down to the electrical connection. The induction heating coils 15 each have long sides 16a to 16h and short sides 17a to 17h. At the corners they are slightly rounded because of the better guidance of the outer coil turns 19, since they should not be bent. Nevertheless, induction heating coils with this shape are to be regarded below as rectangular or at least approximately rectangular, as explained in the introduction.

Above the coil turns 19a to 19h ferrite rods 20a to 20h are placed. The coil windings 19a to 19h themselves are applied to bobbins 21a to 21h, and these bobbins 21 are then again arranged on the support plate 13.

It can be seen that the induction heating coils 15a to 15h each have a certain distance to their adjacent coils, which in practice may be 1 cm to 3 cm or even 5 cm, with rather smaller spacings being preferred. As a result, neighboring areas 23 are formed, namely adjacent areas between long sides 16 of the induction heating coils, namely the neighboring areas 23ab, 23bc, 23cd, 23ef, 23fg and 23gh. These neighboring areas 23 are all the same width and the same length. Furthermore, the induction heating coils 15 at their mutually facing or adjacent short sides 17 further neighboring areas, namely the neighboring areas 23ae, 23bf, 23cg and 23dh. These four neighboring areas are each the same length and the same width. They are slightly wider in the embodiment shown here than the long neighboring areas, but this does not play a major role.

In the neighboring areas 23 sensor coils 25 are arranged. These sensor coils 25 are formed as described above, so flat, single-wind or single-layer coils in a round shape with 10 turns to 30 turns. In each of the long neighboring areas, two such sensor coils 25 are arranged, namely the sensor coils 25ab, 25ab ', 25bc, 25bc', 25cd and 25cd 'in the upper three long neighboring areas 23ab, 23bc and 23cd. In the three lower long neighboring areas 23ef, 23fg and 23gh, it is the sensor coils 25ef, 25ef ", 25fg, 25fg ', 25gh and 25gh." In the case of these sensor coils 25 arranged in the long neighboring areas, it can be seen that their center points exactly in the respective direction Otherwise, the sensor coils 25 each overlap the induction heating coils 15 on their long sides 16 one at a time, and in a similar manner Furthermore, although the sensor coils 25 in the long neighboring regions are arranged mirror-symmetrically to an axis through the short neighboring regions, it can be seen that, for example, in the upper region of the induction hob 11, the upper sensor coil 25ab continues from the upper short sides 17a and 17b of the induction heating coils 15a and 15b are arranged as the lower sensors coil 25ab 'from the lower short sides 17a' and 17b '. This difference can be a few cm, but it is clear. The displacement may be a few cm, for example 1 cm to 5 cm. As a result, as already mentioned, the sensor coil density or detection accuracy in the central region of the entire induction hob 11 is improved in comparison to the upper and lower edge regions.

In the short neighboring areas 23ae, 23bf, 23cg and 23dh also sensor coils 25 are arranged. These are also arranged exactly along a central longitudinal axis of the short neighboring areas, so overlap the respective upper and the respective lower induction heating coil 15 evenly, for example, also with one to three coil turns. These sensor coils 25 also have a small offset from the centric arrangement to the induction heating coils, so the sensor coils 25ae and 25cg are slightly displaced to the left from the center of the short sides 17 of the respectively adjacent induction heating coils 15. This displacement can be done by about 1 cm. By contrast, the sensor coils 25bf and 25dh are shifted to the right by the same amount. Again, this has proven to be advantageous in the context of the invention for the detection of erected pots.

Finally, 15 sensor coils are arranged in central areas of the induction heating coils, namely the sensor coils 25a, 25b, 25c, 25d, 25e, 25f, 25g and 25h. These are centered with respect to the long sides 16 of the induction heating coils, but shifted a short distance to the left or to the right from the center of the short sides 17 in the short neighboring areas 23 corresponding to the sensor coils 25ae, 25bf, 25cg and 25dh.

All sensor coils 25 are connected to a control of the induction hob 11, not shown here. A method for their control will be explained below. In their middle, they each carry a previously mentioned temperature sensor, indicated by the central small circle, which is advantageously a PT1000. The temperature sensors may be connected to the aforementioned controller.

In the front area, the induction hob 11 has an operating area 27 with indicators and controls for adjusting the power of cooking zones, which are formed in different ways by one or more induction heating coils 15.

In the Fig. 2 Several options for erected pots are shown. In the left upper area a very large pot 29a is placed, in the front middle area a medium sized pot 29b and right above a small pot 29c.

The pot 29a covers large portions of the induction heating coils 15a and 15b and small portions of the lower induction heating coils 15e and 15f. Furthermore, the sensor coils 25ab, 25ab ', 25ef, 25ae and 25bf as well as 25a and 25b are completely covered. This means that these sensor coils primarily recognize the presence of a raised pot above them. However, they do not realize that this is a single quasi-related and common with the same heat to be heated pot. Therefore, the overlay information of the induction heating coils 15 is still used. Since none of the sensor coil 25e or 25ef 'otherwise belonging to the induction heating coil 15e recognizes the presence of a pot, but the sensor coils 25fg and 25fg' simultaneously detect the presence of the center cup 29b, which explains the higher degree of coverage of the induction heating coil 15f, control of the Induction hob 11 to conclude that just a very large pot is set up and this seven sensor coils covers, so he must have approximately the size of the large pot 29 a. In this case, due to the insufficient coverage of the lower induction heating coil 15e, it will not be operated, and the adjacent induction heating coil 15f will not. The pot 29a is thus heated only by means of the two upper induction heating coils 15a and 15b. In some cases, even the information to an operator could be output here that the pot 29a should be pushed a little more over the two upper induction heating coils 15a and 15b so that it is heated more uniformly. But this is an optional extra feature. Also can be drawn by further evaluation of the sensor signal conclusions on the pot material.

Due to the extensive coverage of the induction heating coil 15g with complete coverage of the sensor coils 25g, 25fg and 25fg 'and the partial coverage of the sensor coil 25gh' without overlapping of the sensor coils 25gh and 25g and 25e can be closed to the size of the pot 29b. Furthermore, the controller may also recognize that this pot 29b partially projects beyond the induction heating coil 15e. However, since the controller can recognize that the induction heating coil 15f is just as far covered by the pot 29a as the induction coil 15e due to the size and the arrangement of the pot 29a, it can recognize that the overall somewhat higher coverage of the induction heating coil 15f is additionally enhanced by a Part of the further pot 29b comes, but in turn this proportion is too low to justify heating by the induction heating coil 15f. Therefore, the pot 29b is heated only with the induction heating coil 15g. However, it should be noted, however, that the overall degree of coverage of the induction heating coil 15f, taken alone, could be sufficient to start a heating operation for a presumably placed pot.

The induction heating coil 15d detects an overlap of about 30% to 40%. At the same time, the sensor coils 25d, 25cd 'and 25dh recognize a partial overlap. However, the induction heating coils 15c and 15h have no overlap. Thus, it can be seen that a pot is placed only above the induction heating coil 15d, and also its approximate size can be seen. Since even such small pots are to be heated inductively with the induction hob 11, the induction heating coil 15d just starts the heating operation for the pot 29c with a power level inputted to the operating section 27.

From the explanation of the large pot 29a top left is given the Fig. 2 to recognize that the overlap information of the induction heating coils 15 on the one hand and the affected sensor coils 25 on the other hand necessarily the presence of a single pot, and also about this size mean. If the pot 29a were even larger at the same center, it would very quickly cover the sensor coil 25bc 'and thus cause a signal at it. If it were even larger, but shifted slightly to the left, so to speak, so that its degree of coverage of the induction heating coils 15a and 15b would be greater, this would still mean the same heating mode, namely just by means of the induction heating coils 15a and 15b, which together then a cooking place for make this pot. If pot 29a were not circular, but oblong in the manner of a brewer, it could only be larger without covering additional sensor coils 25 in the downward direction, that is, more strongly via induction heating coils 15e and 15f. But then their degree of coverage would increase or one of the sensor coils 25e, 25f or 25ef 'would detect the presence of a pot over itself. If a certain overlap of the induction heating coils is achieved, or at the latest when overlapping one of the said sensor coils, then an additional operation of the induction heating coils 15e and 15f would also be justified.

Furthermore, it can also be clearly seen, for example, that the overlap of the sensor coil 25ef with such a small overlap of the induction heating coils 15e and 15f and the sensor coils 25ae and 25bf means that the sensor coil 25ef is covered by the same pot. Although, in principle, it would also be possible to cover it with a very small pot, which is placed essentially centrally above the sensor coil 25ef. Then, however, the sensor coils 25ae and 25bf could not be covered, except once again by very small pots. However, this would not justify the overall large degree of coverage of the induction heating coils 15a and 15b when the other four sensor coils are covered by the pot 29a. Furthermore, as explained above, all covering information of all Induktionsheizspulen 15 and all sensor coils 25 is always evaluated, and by recognizing the pot 29b can also explain the additional, caused by this pot coverage of Induktionsheizspule 15f.

Furthermore, it can also be seen that the covering by the two pots 29a and 29b can not be done by a single large pot. Otherwise, the coverage of the induction heating coil 15f would be greater, furthermore, the induction heating coil 15c would have to be at least have a low degree of coverage and especially the sensor coils 25 bc 'and 25 f, which are not covered. The same applies to the sensor coil 25cg.

Claims (15)

Induction hob with - a hob plate, - Several arranged under the hob induction coil and a plurality of sensor coils arranged under the hob plate,
characterized in that the induction heating coils are rectangular or approximately rectangular in shape, at least two induction heating coils are arranged one behind the other and at least three induction heating coils are arranged side by side, two adjacent induction heating coils form a neighboring area with each other, both induction heating coils lying with their adjacent sides in the neighboring area, in each neighboring area at least one sensor coil is arranged, exactly one single sensor coil is provided in a direction of distance from one induction heating coil to the adjacent induction heating coil. Induction hob according to claim 1, characterized in that in at least one adjacent area at least two sensor coils are provided side by side along the adjacent sides of the induction heating coils. Induction hob according to claim 1 or 2, characterized in that a center of a sensor coil is located between the adjacent sides of the induction heating coils. Induction hob according to claim 1, characterized in that a sensor coil is arranged above a central region or central region of an induction heating coil, preferably each induction heating coil. Induction hob according to one of the preceding claims, characterized in that all induction heating coils are of the same size and / or identical, wherein preferably all induction heating coils have the same winding direction. Induction hob according to one of the preceding claims, characterized in that in adjacent areas on two induction heating coils, with their short sides are arranged adjacent to each other, exactly one single sensor coil, wherein preferably in adjacent areas between two induction heating coils, which are arranged with their long sides adjacent to each other, exactly two sensor coils are provided. Induction hob according to one of the preceding claims, characterized in that the sensor coils along the long sides are not uniformly or symmetrically distributed, but are displaced towards a central region of the induction cooktop and away from the edge. Induction hob according to one of the preceding claims, characterized in that in neighboring areas between two adjacent induction heating coils, in which only a single sensor coil is provided, these sensor coil are arranged centrally with respect to. The extending in the adjacent areas longitudinal sides of the induction heating. Induction hob according to one of the preceding claims, characterized in that the sensor coils have a round shape, in particular a circular shape, wherein they preferably have ten to forty turns. Induction hob according to one of the preceding claims, characterized in that the sensor coils extend at least partially above the induction heating coils and / or are arranged, wherein the sensor coils overlap the induction heating coils uniformly and similarly to the same extent. Induction hob according to one of the preceding claims, characterized in that the induction heating coils and / or the sensor coils have a single layer of turns or the turns extend in a single layer or plane. Induction hob according to one of the preceding claims, characterized in that the sensor coils have or carry a temperature sensor, preferably in its central region, wherein in particular the temperature sensor is a temperature-dependent resistor. Method for controlling an induction hob according to one of the preceding claims, characterized in that the sensor coils are always operated or detect whether a pot is placed on the hob plate above them. A method according to claim 13, characterized in that the resonant frequency of the sensor coils and their evaluation circuit is clearly, preferably 5 times to 30 times higher, above the operating frequency of the induction coil. A method according to claim 13 or 14, characterized in that an induction coil is only put into operation if at least one of the sensor coils is covered by a pot.

Images