EP2034799A1 - Hob with a sensor device and method for detecting cooking utensils on a hob - Google Patents

Abstract

The hob has a sensor device (10) for detecting cookware elements (16a, 16b) positioned on a cooking surface, where the sensor device is provided with multiple sensor elements (12) e.g. induction heat elements, arranged in a sensor raster. A control unit (14) activates and deactivates the sensor elements according to a search program, where the control unit activates selection of one of the sensor elements to detect the cookware elements. The control element activates selection of another sensor element when the cookware elements are detected by the former sensor element. An independent claim is also included for a method for detecting cookware elements positioned on a cooking surface.

Description

The invention relates to a hob with a sensor device according to the preamble of claim 1 and a method for detecting cookware on a hob according to the preamble of claim 12.

Cooking hobs, in particular so-called matrix cooking hobs, are known from the prior art with a sensor device for detecting cooking utensils placed on a cooking surface. The sensor device has sensor elements which are arranged in a mostly rectilinear, right-angled sensor raster beneath a glass-ceramic cover plate of the hob. For detecting cookware, the sensor elements are activated or deactivated in accordance with a predetermined search program by a control unit of the hob.

In induction cooking fields, it is known to use the inductor heating elements as sensor elements and to detect the cookware with the aid of a loss angle or an inductance of the inductor heating element influenced by the feedback of the cookware element. According to the known search programs, all sensor elements for detecting the cookware are activated simultaneously. In a standby mode, in which the control unit must periodically execute the search program with a period of at most a few seconds in order not to miss setting up a cookware element, this can be due to the large number of data read in parallel to a comparatively high demand for computing power and the activation energy of the sensor elements lead to a high power consumption in standby mode.

The invention is in particular the object of providing a hob, which has a search program with a high energy efficiency.

The invention is particularly based on a hob with a sensor device for detecting mounted on a cooking surface cookware with in a sensor grid arranged sensor elements and a control unit for activating and deactivating the sensor elements according to a search program.

According to one aspect of the invention, it is proposed that the control unit is designed to activate a selection of different sensor elements in a time sequence for coarse-mesh detection of the cookware in at least one first detection step and then, if cookware has been detected by at least one sensor element, in a second Detection step to activate sensor elements in an environment of this sensor element. In the first detection step, an energy-saving operation of the search program with a coarse spatial resolution can be realized, while a high spatial resolution and the associated energy-intensive activation of many sensor elements, the evaluation of which also requires a high computational effort, in the second detection step only in the environment of already recognized in the first detection step cookware elements must be made. An inefficient use of energy and computational resources by high-resolution scanning of empty areas of the cooking rock can be avoided.

In particular, any structure with a mesh size greater than the mesh size of the sensor raster should be referred to as coarse mesh in this context.

According to a further aspect of the invention, it is proposed that the control unit is designed to activate sensor elements in a partial grid of the sensor raster which is coarsely meshed in comparison to the sensor raster in the first detection step. In this context, the grid should be a set of points formed by the crossing points of at least two lines of lines, in particular of parallel lines of lines. A partial grid is a grid formed by subshares of the lineages.

It is further proposed to design the control unit such that in each case one sensor element is activated from a plurality of disjoint groups of sensor elements, and different elements of each group are successively activated in chronological order. Particularly in the case of groups with a congruent geometry, sensor elements whose positions correspond to one another can be assigned to an equivalence class. In the temporal sequences, the elements of an equivalence class can be activated simultaneously and all equivalence classes can be run through in succession. For example In each case, four adjacent sensor elements arranged in a square can be combined to form a group, wherein, for example, the sensor elements defining the group at the bottom left are combined into an equivalence class. For example, the equivalence classes may be traversed such that their representatives are changed clockwise or counterclockwise. In possible embodiments, the selection of the sensor elements may comprise only one sensor element and / or be a random selection.

If the control unit is designed to periodically change the coarse mesh subgrid used in the first detection step, the entire area of the cooktop can be scanned in the course of a period despite the low spatial resolution used in the first detection step, so that even very small cookware elements that are in use the coarse spatial resolution are not recognizable, can be detected.

A systematic search for cookware can be achieved in that the control unit is designed such that in the second detection step all sensor elements contained in an environment with a predetermined radius are activated. The radius can be chosen depending on a lattice constant of the sensor raster so that on the one hand the energy consumption during detection is kept within limits and on the other hand, the detection is sufficiently fast.

In a particularly advantageous embodiment of the invention, the second detection step is repeated inductively, wherein the sensor elements, in the position of a cookware element has been detected, are selected as the center of a new environment. Sensor elements that have already been activated in the previous detection step and that lie within the environment need not be reactivated.

Because of the heating zones which can be defined in a particularly flexible manner, the advantages of the invention are obtained, in particular, in cooktops with induction heating elements arranged in the sensor grid. Such hobs are often referred to as matrix hobs. For example, you can include 16 sensor elements and heating elements in a 4 x 4 grid or 25 sensor elements and heating elements in a 5 x 5 grid.

Separate sensor elements may be dispensed with if the sensor elements are the induction heating elements. The induction heating elements include inductor coils that can be used for inductive detection of the cookware. If, however, further sensor elements, for example capacitive sensors, are used in addition to the induction heating elements, it is advantageous if, after the detection of the position and size of the cookware element in a further detection step by means of a check of a loss angle and / or an inductance of the induction heating is determined the detected cookware element is heated by the induction heating elements.

It is also proposed that the control unit is designed to activate the sensor elements in a time sequence with a first sampling frequency in a normal operation and to activate the sensor elements in a time sequence with a second sampling frequency in a fast search operation, wherein the second sampling frequency is higher than the first sampling frequency. This can be saved in a normal operation - for example, in a standby mode in which the hob is periodically scanned for new cookware elements, energy, while fast search mode fast cookware detection is possible.

In this case, the control unit is advantageously designed such that it activates the quick search mode when a signal of a user has been detected. Such a signal can be given by the switching on of the hob or a specific heating zone or heating function or by the direct start of the quick search operation by a selection of the operator.

If the hob comprises means for selecting a portion of the hob, and the controller is configured to concentrate the search program on the selected portion, further acceleration of the process and energy savings can be achieved. For example, on a touch screen representing the cooktop, the operator may select the approximate position of the cookware element and the controller may start the search program from the selected position, for example by activating the sensor elements in concentric widening circles and after detecting a cookware element at least one sensor element repeats the second detection step described above is performed until the entire bottom surface of the cooking utensil element is detected. According to a further conceivable embodiment of the invention, the sensor elements are activated in a coarse-meshed sub-grid in a vicinity of the center of the area selected by the operator, thus performing a detection with low resolution, which is subsequently improved by a second detection step.

Furthermore, it is proposed that the control unit is designed, when it has been detected that a cookware element has been removed from the area of a sensor element, to start a search program for tracking a movement of the cookware element. The search program for tracking the movement of the cooking utensil element can be done by activating the sensor elements in a coarse-meshed sub-grid in a lower resolution in order to detect even rapid movements of the cooking utensil. The more accurate detection of the cooking utensil element may be made after completion of the movement in another mode of operation. Furthermore, the sampling frequency of the search program can be increased upon detecting a movement.

Another aspect of the invention relates to a method for detecting cookware on a hob by means of a sensor device comprising sensor elements arranged in a sensor raster.

It is proposed that in at least one first detection step different sensor elements are activated in a chronological order and then, if at least one sensor element cookware was detected, sensor elements in an environment of this sensor element are activated in a second detection step. The method achieves the above advantages in terms of improving the efficiency of the cooktop.

Further advantages emerge from the following description of the drawing. In the drawing, an embodiment of the invention is shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

ein schematisch dargestelltes Kochfeld mit einer Sensorvorrichtung zum Detektieren von auf einer Kochfläche aufgestelltem Kochgeschirr und einem Display,

Fig. 2a - 2d

verschiedene Phasen eines periodischen ein Schemas zum Aktivieren der Sensoreinheiten der Sensorvorrichtung aus Figur 1,

Fig.

3a und 3b eine schematische Darstellung eines ersten Detektionsschritts und eines zweiten Detektionsschritts eines erfindungsgemäßen Verfahrens zum Detektieren von Kochgeschirr auf einem Kochfeld und

Fig. 4

eine schematische Darstellung des Verfahrens zum Detektieren von Kochgeschirr auf dem Kochfeld.

Show it:

Fig. 1

a schematically illustrated hob with a sensor device for detecting mounted on a cooking surface cookware and a display,

Fig. 2a - 2d

different phases of a periodic a scheme for activating the sensor units of the sensor device FIG. 1 .

FIG.

3a and 3b a schematic representation of a first detection step and a second detection step of a method according to the invention for detecting cookware on a hob and

Fig. 4

a schematic representation of the method for detecting cookware on the hob.

FIG. 1 shows a hob with a sensor device 10 for detecting mounted on a designed as a glass ceramic hob cooking utensils 16. The sensor device 10 includes a plurality of arranged in a sensor grid sensor elements 12, which simultaneously form heating elements of the hob and are arranged below the cooking surface. The cooktop comprises a control unit 14 for controlling an operation of the cooktop and the sensor device 10. The control unit 14 evaluates the signals of the sensor elements 12 and is further designed by interfaces to activate and / or deactivate the sensor elements 12. The sensor elements 12 can be controlled independently of each other. The control unit 14 is a universally programmable arithmetic unit. It actuates the sensor elements 12 in accordance with a search program implemented in the control unit 14.

The cooktop is a matrix-type induction cooktop. It comprises a plurality of induction radiators, in the illustrated, simplified embodiment 48 pieces. The induction heaters are arranged in a square 6 x 8 grid. There are embodiments of the invention with well over 48 or less than 48 induction heaters conceivable.

The induction heaters are essentially induction coils and are simultaneously used as sensor elements 12. For this purpose, the control unit 14 generates an alternating current in the induction coil and detects a loss angle and / or an inductance of the induction coil or the induction heater. If one or both values deviate from a normal value by more than a predetermined threshold value, the control unit 14 recognizes that the respective sensor element 12 or induction heating element is covered by a cookware element 16. The normal value corresponds to the value of the loss angle or the inductance in the case of a free cooking surface, ie without the cookware 16 set up.

The search program is used to detect an area covered by a pot or pan bottom surface of the hob. Depending on the area detected, the control unit 14 flexibly defines an area approximately corresponding heating zone from a group of induction heaters.

The control unit 14 controls a display 18 by way of a graphic interface (not explicitly shown here) on which results of the search program and active heating zones defined as a function of the results of the search program are graphically displayed during operation.

In the in FIG. 1 illustrated configuration, two cookware elements 16a, 16b are arranged on the hob. The horizontally hatched induction heating elements or sensor elements 12 are completely covered by one of the cookware elements 16a, 16b and are each grouped in a heating zone associated with the corresponding cookware element 16a, 16b.

According to the invention, the control unit 14 is designed by suitable software to activate in a first detection step a selection of different sensor elements 12 in a temporal sequence for coarse mesh detection of the cookware and then when at least one sensor element 12 cookware 16 has been detected in To activate a second detection step sensor elements 12 in an environment of this sensor element 12.

The first detection step is repeated periodically when no cookware element 16a, 16b has been detected. The state of the hob goes through four phases that are in the FIGS. 2a-2d are shown schematically. The FIGS. 2a-2d show only one Section of the hob with 16 induction heating elements. The in the FIGS. 2a-2d Patterns shown are periodically continued over the entire cooking surface area.

The software of the control unit 14 is configured such that in the first detection step sensor elements 12 are activated in a partial grid of the sensor raster which is coarsely meshed in comparison to the sensor raster. In the present embodiment, the sensor elements 12 are divided into groups, each with four sensor elements 12, each corresponding to a square section of the entire hob. The four sensor elements 12 in a group are each arranged in a square, so that the groups are geometrically congruent. The control unit 14 activates the respective equivalent sensor elements 12 from the different groups simultaneously. Equivalent are the sensor elements 12 with the same position within the group - that is, for example, the front left sensor elements 12 in the operator's view. The four possible positions of the sensor elements 12 within a group define four equivalence classes of sensor elements 12. The four elements of an equivalence class form a coarse-meshed sub-grid whose points are separated by a respective not belonging to the sub-grid point of the sensor raster.

The FIGS. 2a-2d show phases in which each of the sensor elements 12 of an equivalence class are activated. The activated sensor elements 12 are each hatched. In the chronological order are in the FIGS. 2a-2d cycle through the states shown.

Accordingly, the control unit 14 in each case activates a sensor element 12 from the disjoint groups of sensor elements 12, each consisting of four adjacent sensor elements 12. These groups of sensor elements 12 are arranged in the FIGS. 2a-2d each indicated by a dashed circle. In the temporal sequence, the control unit 14 passes through the equivalence classes such that, within each group of sensor elements 12, each individual sensor element 12 is periodically activated and deactivated. Within a group, the sensor elements 12 are activated in a clockwise direction. A clock in which the active sensor elements 12 are reversed, is about 1 second, so that the period is about 4 seconds. Thus, the control unit 14 is configured to periodically change the coarse mesh subgrid used in the first detection step.

FIG. 3a shows the state of the hob during a first, FIG. 2a corresponding phase of the four phases of the first detection step, which corresponds to a standby search operation. If the control unit 14 has not detected a cookware element 16 in the first detection step, the time sequence described above is repeated until either the search program is ended - for example by switching off the hob - or until a cookware element 16 is found. In the latter case, if, for example, as in FIG. 3a 4, the control unit 14 has detected the overlap of a particular sensor element 12a with a cookware element, the search program jumps to the second detection step, in which the size, shape and position of the cookware element 16 is measured in a higher spatial resolution.

The second detection step is schematically in FIG FIG. 3b dargstellt. In the second detection step, the control unit 14 activates all sensor elements 12 contained in an environment with a predetermined radius R, that is to say those which are not connected to the previously activated coarse-mesh subgrid (FIG. FIG. 3a ) belonging sensor elements 12th

In the in FIG. 3b In the second detection step, the vertically hatched sensor elements 12 are activated and the control unit 14 will detect the cookware element 16 in the region of three further sensor elements 12b-12d.

The second detection step is repeated accordingly, wherein in the next detection step, the sensor elements 12, which have detected a cookware element adjacent sensor elements 12 are activated, unless they were already activated in the previous detection step.

In the in FIG. 3b In the configuration shown, the sensor elements 12e, which are activated in the further detection step and are shown horizontally hatched, do not detect any cookware element, so that the search program would have been completed in this example and the control unit 14 would be the one described in FIG FIG. 3b shown in bold lines, as sensor elements used 12a - 12d induction heating elements to a heating zone can summarize. Thereafter, the control unit 14 again jumps to a standby mode with respect to the cookware search, in which the first detection step with a coarse scan of the hob with the outside of the heating zone as described above arranged sensor elements 12 is repeated for periodic scanning of the hob.

While the control unit 14 according to the search program in a normal operation activates the sensor elements 12 in a time sequence with a first sampling frequency of, for example, 1 s ^-1 , with which the phases of the first detection step are traversed, in a quick search operation, the sensor elements 12 in a time series activated with a second sampling frequency, wherein the second sampling frequency is higher than the first sampling frequency and several hertz. For example, the time interval between the detection of a cookware element 16 in the first detection step and the start of the second detection step as well as between the second detection step and the further detection step may be less than the actual distance between them FIGS. 2a-2d illustrated phases of the first detection step.

The control unit 14 activates the quick search operation when a signal of a user has been detected. The user signal may be, for example, either the actuation of a search key not shown here, the switching on of a cooktop by the actuation of a temperature selector switch or the selection of a hob area.

The touch screen or display 18 forms a means for selecting a portion of the hob, the control unit 14 being adapted to concentrate the search program on the selected area. The search program activates the sensor elements 12 starting from the center in concentric circles in the in FIG. 3b first shown in a coarse-meshed sub-grid and then, in a second detection step, which is started when a cookware element was detected, with a higher spatial resolution.

The software of the control unit 14 also includes a special search program for tracking a movement of the cookware element 16. This particular search program is then started when it has been detected that a cookware element 16 has been removed from the area of a sensor element 12. For this purpose, the control unit 14 periodically activates the sensor elements 12 in a region in which a cookware element has already been detected. If the control unit 14 recognizes from the detected impedance characteristics that the cookware element 16, the sensor element 12 and the Induction heating is no longer covered, the special search program is turned on.

FIG. 4 shows schematically a method for detecting cookware 16 on a hob of the type described above. The method uses a sensor device 10 of the hob, which comprises sensor elements 12 arranged in a sensor grid.

In a first detection step, which is repeated periodically when no cookware element has been detected, various sensor elements 12 in the above in connection with the FIGS. 2a-2d activated chronological sequence. If cookware 16 has been detected by at least one sensor element 12, sensor elements 12 in an environment of this sensor element 12 are activated in a second detection step.

reference numeral

10

sensor device

12

sensor element

14

Steuereinhiet

16

Cookware

16a

Cookware element

16b

Cookware element

18

display

Claims (12)

Hob with a sensor device (10) for detecting cookware (16, 16a, 16b) mounted on a cooking surface with sensor elements (12) arranged in a sensor grid and a control unit (14) for activating and deactivating the sensor elements (12) according to a search program, characterized in that the control unit (14) is adapted to activate a selection of different sensor elements (12) in at least one first detection step for coarse-mesh detection of the cookware (16, 16a, 16b) and then if at least one sensor element (12) Cookware (16, 16a, 16b) was detected, in a second detection step to activate sensor elements (12) in an environment of this sensor element (12). Hob according to claim 1, characterized in that the control unit (14) is adapted to activate in the first detection step sensor elements (12) in a coarse mesh compared to the sensor raster sub-grid of the sensor raster. Cooking field according to one of the preceding claims, characterized in that the control unit (14) is adapted to simultaneously activate a plurality of sensor elements (12), in each case one sensor element (12) of a plurality of disjoint groups, and in the temporal sequence all elements of the to go through disjoint groups. Hob according to one of the preceding claims, characterized in that the control unit (14) is adapted to periodically change the coarse-mesh partial grid used in the first detection step. Cooking field according to one of the preceding claims, characterized in that the control unit (14) is designed to activate in the second detection step all sensor elements (12) contained in an environment with a predetermined radius (R). Cooking field according to one of the preceding claims, characterized by induction heating elements arranged in the sensor grid. Hob according to claim 5, characterized in that the sensor elements (12) are the induction heating elements. Hob according to one of the preceding claims, characterized in that the control unit (14) is adapted to activate in a normal operation, the sensor elements (12) in a time series with a first sampling frequency and in a quick search operation, the sensor elements (12) in a temporal Sequence to activate with a second sampling frequency, wherein the second sampling frequency is higher than the first sampling frequency. Hob according to claim 7, characterized in that the control unit (14) is adapted to activate the quick search mode when a signal of a user has been detected. Hob according to one of the preceding claims, characterized by means (18) for selecting a region of the hob, wherein the control unit (14) is adapted to concentrate the search program on the selected region. Hob according to one of the preceding claims, characterized in that the control unit (14) is designed, then, when it has been detected that a cookware element has been removed from the region of a sensor element (12) to start a search program for tracking a movement of the cooking utensil element , Method for detecting cookware (16, 16a, 16b) on a hob by means of a sensor device (10) comprising sensor elements (12) arranged in a sensor raster, characterized in that in at least one first detection step for coarse detection of the cookware (16 , 16a, 16b) different sensor elements (12) are activated in a chronological order and then, when at least one sensor element (12) cookware (16, 16a, 16b) has been detected, in a second detection step, sensor elements (12) in an environment thereof Sensor element (12) are activated.

Images