EP2981154B1 - Method and device for recognizing the position of a pot on an induction hob - Google Patents

Description

Field of application and state of the art

The invention relates to a method and a correspondingly designed device or such induction hob for detecting the position of a pot on an induction hob or at a cooking point of the induction hob.
From the DE 102004016631 A1 An arrangement is known with which the placement of a pot and its position can be detected at a heating or cooking of a hob. Here, a plurality of capacitively acting sensors are provided in the outer area of a cooking area or a heating device associated with the cooking area, in particular a radiant heater.

From the EP 2 312 908 A1 is an induction hob with induction coils known to form cooking zones. In addition to the induction coils sensor coils are provided to detect a plate on a hob placed cookware element. In this case, measuring currents in the sensors detect the inductance and / or a loss angle of an overall system formed from the sensors and the cookware element in order to deduce the presence of the cooking utensil element.

From the GB 2 055 030 A and the JP S56 22080 A Induction hobs are known in which four distributed magnetic sensor coils are provided below one level of the induction heating coil. These are arranged radially outside of the induction heating coil. Via a time-varying magnetic field and a connected circuit, a signal is generated when a magnetic cooking pot is placed on the induction heating coil decentered. If the decentric touch or signal generated as a result exceeds a certain limit, a warning is issued to an operator.

From the JP H07 254484 A An induction cooker is known with an induction heating coil and detection coils arranged outside its outer edge. With these, the placement of a cooking vessel can be detected. Further details on the operation are not specified.

From the JP 2012 146423 A For example, another induction hob is known with detection coils that can be located both within the surface of an induction heating coil and outwardly outboard therefrom. These also serve to be able to detect a mounted on a cooking above the induction heating coil cookware element.

Task and solution

The invention has for its object to provide an aforementioned method and trained to carry out a device or an induction hob, with which problems of the prior art can be eliminated and it is particularly possible, both the placement of a pot on a hotplate also be able to reliably recognize its correct position and, if necessary, be able to display it to an operator.

This object is achieved by a method having the features of claim 1 and a device having the features of claim 7 or by an inventive induction hob with such a device. Advantageous and preferred embodiments of Invention are the subject of further claims and are explained in more detail below. In this case, some of the features are described and explained only for the method or only for the device or the induction hob.

It is provided that a pot is arranged or arranged above or in the region of an induction coil of a cooking point of the induction hob. Externally adjacent to the induction coil at least three detection coils are arranged or in the edge region of the cooking area intended. It may be, for example, three or four detection coils, which are then advantageously distributed approximately equal or have clear distance from each other. The detection coils are advantageously provided relatively close to the induction coil or on an outer edge of the induction coil. They can also be arranged such that an edge marking the cooking surface or a corresponding border runs over the surface of the detection coil. A correctly placed on the cooking pot pot of a correct or intended size, the at least one detection coil should at least cover something, but advantageously not completely. According to the invention, at least three detection coils are provided per induction coil or per hotplate. Each of the detection coils produces, as a sort of transmitter, its own field, which is influenced and damped by the pot depending on its position at the cooking point or above the induction coil. From the damping of all detection coils, which are associated with this cooking point or induction coil, or a comparison of the damping with each other, the distance to the pot and thus the position of the pot at the hob can be determined or calculated. Here, the detection coils work as a sort of receiver. Thus, the detection coils in this alternative work independently and independently or detached from the induction coil. On the one hand, this has the advantage that the operation of the induction coil or the heating operation for the pot does not have to be interrupted, not even for a short time. Furthermore, the detection coils can thus operate in the detection mode or at a frequency which is optimized for cup detection and possibly or advantageously deviates from the optimum frequency for the heating coil for the heating operation.

In a further embodiment of the invention, a plurality of detection coils on an induction coil or hob are present and evenly distributed. Their distances from one another can vary, for example, by a maximum of 200%, preferably by a maximum of 25% to 100%.

In an advantageous embodiment of the invention, a plurality of induction coils may be provided or be present on an induction hob. For example, it may be either four or six induction coils per induction hob, which are distributed in the manner of normal cooking zones, each one induction coil forms a cooking point. Alternatively, far more induction coils may be provided, for example according to the EP 1463383 A1 , Here, a plurality of induction coils is provided, wherein in each case a plurality of induction coils, which are just covered by a pot in a corresponding extent, working together as a cooking place or take over the inductive heating of this pot.

In general, the detection coils can each be provided in intermediate spaces between the induction coils, so that a total of three or four detection coils are provided on the edge of an induction coil. Each detection coil is provided near the edge of two or three induction coils.

A center of the detection coils may lie in a space between induction coils or between the induction coils. By its own size expansion it is possible that the detection coils themselves overlap in area with the induction coils. The detection coils are then advantageously arranged in a surface or a plane above the induction coils.

In general, it is possible that the detection coils at certain time intervals, for example, every 2 seconds to 10 seconds or even 20 seconds, briefly go into the detection mode and check how the position of the pot is at the hob. Whether a change has taken place. An area between 2 seconds and 5 seconds is regarded as advantageous here. According to the invention, in heating mode, a frequency for the signals of the transmitter is several times the operating frequency of the induction coil. It is particularly advantageous 5 times to 15 times. For example, if the induction coil operates at a frequency of 17 kHz and greater, for example 50 kHz or even 80 kHz, the transmitter operates at a frequency of approximately 80 kHz to 1 MHz or even slightly higher. This also ensures that no interference occurs. However, frequencies in the range of 150 kHz or 200 kHz up to 300 kHz or 400 kHz are considered to be particularly advantageous.

For example, if three detection coils associated with an induction coil, and have the same distance to the induction coil or its outermost turn, for example 1 cm to 5cm, so reduced over the induction coil on the cooking pot pot sets the field strength at the detection coils symmetrically or similar and the same strong. If, on the other hand, a pot is not placed centrically or displaced accordingly, the field strength at the detection coils is reduced asymmetrically or unevenly. Based on this asymmetry, the position or the displacement of the pot can be detected from the centric position.

After recognizing a noncentric or improperly placed pot different actions can follow. Thus, an operator can easily be made aware of it by an optical and / or acoustic signal. Alternatively, the heating operation can be influenced on the induction coil, for example, the power can be lowered slightly. In still further alternatives, with an above-described principle of many induction coils per hob, an induction coil obviously not full or sufficiently covered can be switched off and another that is not yet in operation but sufficiently covered will be turned on for heating.

The detection coils are advantageously arranged below the hob plate. They can either be arranged on the same flat carrier as the induction coil. Alternatively, they may be attached to the induction coils or on top thereof.

The detection coils may have a relatively small diameter, for example 1 cm to 3 cm or a maximum of 5 cm. They are advantageously wound round or at least approximately round and have a plurality of turns, wherein they are arranged flat or parallel to the induction coil and to a hob plate. They can have turns in one or two levels.

Brief description of the drawings

Fig. 1

eine prinzipielle Schrägansicht einer Induktionsspule als Sender mit drei benachbarten Erkennungsspulen als Empfänger ohne Topf, wobei eine solche Anordnung nicht Teil der beanspruchten Erfindung ist,

Fig. 2

eine Darstellung entsprechend Fig. 1 mit nicht-zentrisch zur Induktionsspule aufgesetztem Topf,

Fig. 3

eine Draufsicht auf die Anordnung aus Fig. 2,

Fig. 4

ein Induktionskochfeld von oben mit vier Induktionsspulen und mehreren direkt benachbarten Erkennungsspulen,

Fig. 5

eine Draufsicht auf eine alternative Ausgestaltung ähnlich der Anordnung aus Fig. 3 ohne Topf, wobei die Erkennungsspulen Sender und Empfänger sind und

Fig. 6

die Anordnung mit der Funktionsweise aus Fig. 5 mit einem entsprechend Fig. 3 versetzt aufgesetzten Topf.

Further advantages and aspects of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are explained below with reference to the figures. Showing:

Fig. 1

a schematic oblique view of an induction coil as a transmitter with three adjacent detection coils as a receiver without pot, such an arrangement is not part of the claimed invention,

Fig. 2

a representation accordingly Fig. 1 with non-centric to the induction coil mounted pot,

Fig. 3

a plan view of the arrangement Fig. 2 .

Fig. 4

an induction hob from above with four induction coils and several directly adjacent detection coils,

Fig. 5

a plan view of an alternative embodiment similar to the arrangement Fig. 3 without pot, where the detection coils are transmitter and receiver and

Fig. 6

the arrangement with the functioning of Fig. 5 with a corresponding Fig. 3 offset mounted pot.

Detailed description of the embodiments

In Fig. 1 schematically shows a rectangular induction coil 11 on a support plate 13 for a hotplate 12 as a device according to the invention. Adjacent to the induction coil 11 13 three detection coils 15 a, 15 b and 15 c are arranged on the support plate, said arrangement in the plan view of Fig. 3 also good to see. The distance of the detection coils 15a to 15c to the induction coil 11 or to its edge can be between 1 cm and 5 cm, in the example shown here between 3cm and 5cm. This distance or the distance form a respectively illustrated air gap 17a, 17b and 17c, which is in each case approximately the same size.

From the Fig. 1 can be seen by the width of the arrows, as in the operation of the induction coil 11 as a transmitter and the detection coils 15a to 15c as a receiver due to the same distance or the same wide air gap 17, the field strength at all detection coils 15a to 15c is approximately the same. It should be noted that the field strength does not have to be the same at all three detection coils as a receiver. It must, however, be known, either by programmed specification or by detection in the manner of a calibration in operation when the pot is not attached. In Fig. 2 is now shown how a pot 19 is non-centrically placed on the induction coil 11, the Fig. 3 shows this in plan view. The pot 19 protrudes with its outer edge to the detection coil 15c. It has the greatest distance to the detection coil 15a. The distance to the detection coil 15b is approximately in between. On the basis of the arrows it can be seen again, which is also easy to imagine that the field strength at the detection coil 15c is greatest, because there the field by means of the metallic pot and its good conductive properties of the induction coil 11 as a transmitter directly to or via the detection coil 15c is directed. For the detection coil 15c, no arrow is shown, since there goes the field directly from the pot 19 above down to the detection coil 15c.

The field strength at the detection coil at the detection coil 15b is just medium, because their distance from the pot 19, although much larger than in the detection coil 15c, but still lower than in the detection coil 15a. From the change in the field strength at the detection coils 15 of the FIGS. 2 and 3 in comparison to Fig. 1 not only a non-centric placement of the pot 19 can be detected on a hob 12, but it can also be recognized in which direction or to which detection coil 15 towards the pot 19 is moved.

In the Fig. 4 is an entire induction hob 21 shown in plan view, but with a virtually transparent hob plate. On the large rectangular support plate 13, four induction coils 11a, 11b, 11c and 11d are arranged. These induction coils 11 are all identical, but this need not be the case. They form hotplates 12a, 12b, 12c and 12d.

Furthermore, seven detection coils 15a to 15g are provided. The detection coils 15a, 15b, 15f and 15g are arranged on the outwardly facing shorter end faces of the induction coils and are only used to detect the position of a placed on exactly this induction coil pot. The detection coil 15b can be used both for the induction coil 11a of the cooking zone 12a and for the induction coil 11c of the cooking zone 12c since it has the same distance to both. The same applies to the detection coil 15e with respect to the induction coils 11b and 11d.

The detection coil 15c in the middle between the four induction coils 11a to 11d works for all these four induction coils. If several pots are placed on the induction hob 21 or a pot is placed on one of the hobs 12a to 12d, a differentiation possibility must be created for the detection coils 15b, 15c and 15e. This can be done either by coded transmission signals of the respective induction coil 11, for example by sending an individual identification for the detection mode. Alternatively, a temporal offset of the operation of the respective induction coil 11 as a transmitter and the detection coils 15 may be provided as a receiver, and this may be only the directly adjacent detection coils.

In the Fig. 5 is similar to the representation of Fig. 1 and 3 an alternative method to an alternative device according to the invention shown. On a rectangular induction coil 111 of a cooking point 112, similar to in FIG Fig. 3 shown adjacent to three detection coils 115a, 115b and 115c. They have the above-described distance, so that in this respect, the structure of the Fig. 1 to 3 could be.

Functionally, the difference here is that not one of the induction coils works as a transmitter, for example as described above, the induction coil 111, and the other detection coils 115 as a receiver. Rather, it is provided here that the three detection coils 115a to 115c emit their own field, which should also extend to the middle of the induction coil 111, but at least the induction coil 111 should clearly overlap. These fields are in Fig. 5 represented by the concentric circles around the detection coils 115a to 115c.

Will now, as in Fig. 6 shown, a pot 119 similar decentered placed as in the FIGS. 2 and 3 is shown, the field strengths change at the detection coils 115a to 115c, in particular results in a higher damping. In the lower right detection coil 115c is a very strong damping because the pot 119, this detection coil 115c is almost overlapped, so it is located very close.

In the detection coil 115b is a moderate attenuation before, since the distance to the pot 119 is still significantly higher than at the detection coil 115c. This distance corresponds to the aforementioned air gap.

The distance to the upper detection coil 115a is greatest, so that the attenuation of the field at the detection coil 115a has the least effect here. Thus, similar to the FIGS. 2 and 3 described, also on the basis of the field strength distribution or damping according to the Fig. 6 the position of the pot 119 are determined at least approximately.

If a control of the induction hob, not shown here, has detected that a pot has been placed non-centrically, it can signal this to an operator. This can be done either as a general error message or as specific with respect to "pot non-centric". This is independent of whether the method according to the Fig. 1 to 4 or 5.6 he follows.

In yet another embodiment of the invention with even more comfort can be determined how far and in which direction the pot is placed decentric. Then an operator can more easily, accurately and comfortably position the pot correctly.

Claims (10)

1. Method for detecting the position of a pan (119) on an induction cooktop (21), wherein the pan (119) is disposed above or in the region of an induction coil (111) of a cooking zone of the induction cooktop (21), wherein at least one detection coil (115) arranged exterior and adjacent to the induction coil (111) or in a boundary region of the cooking zone is provided, wherein at least three detection coils (115) are provided per induction coil (111) and cooking zone (112), respectively, and each detection coil (115) generates a distinct field which is attenuated by the pan (119) as a function of its position, and the position of the pan (119) on the cooking zone (112), or a shifting of the pot (119) on the cooking zone (112) is detected on the basis of the attenuation of all detection coils (115), wherein the induction coil (111) operates with a frequency of 17 kHz to 80 kHz, characterized in that a frequency for the signals of the detection coils (115) is 80 kHz to 1 MHz.
2. Method according to claim 1, characterized in that in the cooking zone (112) or in the vicinity around the induction coil (111) a plurality of detection coils (115) are disposed, preferably three coils, wherein in particular the detection coils (115) are disposed in a uniform distribution pattern.
3. Method according to claim 1 or 2, characterized in that a plurality of induction coils (111) are provided, preferably in a regular arrangement to each other, wherein detection coils (115) are provided and associated with each induction coil (111) in the same arrangement pattern, wherein preferably a plurality of detection coils (115) are assigned to at least two induction coils (111) and arranged, respectively, close thereto and, thus, between the induction coils (111).
4. Method according to any one of the preceding claims, characterized in that a frequency for the signals of the detection coils (115) is more than 150 kHz.
5. Method according claim 4, characterized in that a frequency for the signals of the detection coils (115) is more than 200 kHz.
6. Method according to any one of the preceding claims, characterized in that with a pan (119) placed centrally above the induction coil (111) the field strength on the detection coils (115) is reduced in a manner symmetrical or uniform and to the same degree, wherein with a pan (119) not centrally placed-on the field strength on the detection coils (115) is reduced in a non-symmetrical manner and the position or the shifting from the central position of the pan (119) is detected based on the amount of non-symmetry.
7. Device for implementing the method according to any one of the preceding claims, wherein the induction cooktop (21) has a plurality of cooking zones (12, 112) and a plurality of induction coils (11, 111), wherein each cooking zone (12, 112) is associated with at least one induction coil (11, 111), wherein a pan (19, 119) to be disposed above or in the region of an induction coil (11, 111) or of a cooking zone (12, 112) of the induction cooktop (21) is provided, wherein detection coils (15, 115) arranged exterior and adjacent to the induction coil (11, 111) or in a boundary region of the cooking zone (12, 112) are provided, wherein the induction coil (11, 111) and the detection coils (15, 115) together with their respective control system are configured such that the detection coils (15, 115) send a signal as a transmitter and receive a signal as a receiver and supply it for evaluation, wherein placing a pan (19, 119) onto the cooking zone (12, 112) modulates the emitted signal for detecting said signal modulation by the detection coils (15, 115) and by the evaluation for detecting of a position of the pan (19, 119) on the cooking zone (12, 112) or for detecting of a shifting move of the pan (19, 119) on the cooking zone (12, 112) therefrom, wherein the induction coil (11, 111) operates with a frequency of 17 kHz to 80 kHz, characterized in that a frequency for the signals of the detection coils (15, 115) is 80 kHz to 1 MHz.
8. Device according to claim 7, characterized in that in the cooking zone (12, 112) or in the vicinity around the induction coil (11, 111) a plurality of detection coils (15, 115) are disposed, preferably three coils, wherein in particular the detection coils (15, 115) are disposed in a uniform distribution pattern.
9. Device according to claim 7 or 8, characterized in that the distances of the plurality of detection coils (15, 115) to each other vary by a maximum of 200 %, preferably by a maximum of 25 % to 100 %.
10. Device according to any to claims 7 to 9, characterized in that a plurality of induction coils (11, 111) are provided, preferably in a regular arrangement to each other, wherein detection coils (15, 115) are provided and associated with each induction coil (11, 111) in the same arrangement pattern, wherein preferably a plurality of detection coils (15, 115) are assigned to at least two induction coils (11, 111) and arranged, respectively, close thereto and, thus, between the induction coils.

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