EP3541146A1

EP3541146A1 - Induction cooker and method of operating the induction cooker

Info

Publication number: EP3541146A1
Application number: EP18162102.0A
Authority: EP
Inventors: Mert Serdar BÍLGÍN; Yusuf AK
Original assignee: Vestel Elektronik Sanayi ve Ticaret AS
Current assignee: Vestel Elektronik Sanayi ve Ticaret AS
Priority date: 2018-03-15
Filing date: 2018-03-15
Publication date: 2019-09-18

Abstract

An induction cooker (2) comprises a cooking surface comprising a first heating region (6a, 6b, 6c, 6d) and a second heating region (4). The first heating region (6a, 6b, 6c, 6d) is associated with an induction coil (12a, 12b, 12c, 12d) for inducing a current in a cooking vessel made at least in part of ferromagnetic material and located in use on the first heating region (6a, 6b, 6c, 6d) to heat the cooking vessel. The second heating region (4) has a ferromagnetic plate which is movable relative to the cooking surface to bring the ferromagnetic plate in proximity to at least one of the induction coil (12a, 12b, 12c, 12d) associated with the first heating region (6a, 6b, 6c, 6d) and another induction coil so as to allow a current to be induced in the ferromagnetic plate to heat the ferromagnetic plate.

Description

Technical Field

The present disclosure relates to an induction cooker and a method of operating an induction cooker.

Background

Induction cookers are known in which a varying electric current is passed through an induction coil, the induction coil therefore producing a corresponding a varying electromagnetic field. The varying electromagnetic field induces a varying eddy current in a ferromagnetic cooking vessel or the like when the cooking vessel is placed in close proximity to the induction coil, which in turn heats the cooking vessel and therefore the contents of the cooking vessel. One or more transistors may be used to control the power that is provided to the induction coil by varying the current that is provided to the induction coil.

Summary

According to a first aspect disclosed herein, there is provided an induction cooker comprising:

a cooking surface comprising a first heating region and a second heating region;
the first heating region being associated with an induction coil for inducing a current in a cooking vessel made at least in part of ferromagnetic material and located in use on the first heating region to heat the cooking vessel;
the second heating region having a ferromagnetic plate which is movable relative to the cooking surface to bring the ferromagnetic plate in proximity to at least one of the induction coil associated with the first heating region and another induction coil so as to allow a current to be induced in the ferromagnetic plate to heat the ferromagnetic plate.

The ferromagnetic plate of the second heating region may be movable relative to the cooking surface between a first position wherein the ferromagnetic plate of the second heating region and the cooking surface extend substantially in the same plane and a second position wherein the ferromagnetic plate of the second heating region and the cooking surface extend in different planes.
The ferromagnetic plate of the second heating region may be biased toward the first position and the ferromagnetic plate of the second heating region is configured to move from the first position to the second position under the weight of a cooking vessel placed on the ferromagnetic plate of the second heating region.
The induction coil associated with the first heating region may be movable between a first position wherein the induction coil is arranged to underlie the first heating region to cause heating of a cooking vessel placed in use on the first heating region and a second position wherein the induction coil is moved closer to the ferromagnetic plate of the second heating region to cause heating of the ferromagnetic plate of the second heating region.
The induction cooker may comprise a rail for supporting the induction coil associated with the first heating region and the induction coil associated with the first heating region is configured to be moved along the rail between the first position and the second position.
The rail may be configured so that in the first position a central axis of the induction coil associated with the first heating region is directed toward the first heating region and in the second position the central axis of the induction coil associated with the first heating region is directed toward the ferromagnetic plate of the second heating region.
The second heating region may be smaller than the first heating region.
The cooking surface may comprise four first heating regions and the second heating region is arranged between the four first heating regions.
The first heating region may be made at least in part of non-ferromagnetic material.
The first heating region may be made at least in part of thermally conductive material.
According to a second aspect there is provided a method of operating an induction cooker, the method comprising:
in response to placing a cooking vessel on a second heating region having a ferromagnetic plate, moving the ferromagnetic plate relative to a cooking surface comprising a first heating region and the second heating region to bring the ferromagnetic plate in proximity to at least one of an induction coil associated with the first heating region and another induction coil so as to allow a current to be induced in the ferromagnetic plate to heat the ferromagnetic plate.
The method may comprise:

determining that a cooking vessel placed on the ferromagnetic plate of the second heating region is to be heated; and
moving the induction coil associated with the first heating region from a first position to a second position, wherein in the first position the induction coil associated with the first heating region is arranged to underlie the first heating region to cause heating of a cooking vessel made at least in part of ferromagnetic material placed on the first heating region and in the second position the induction coil is moved closer to the ferromagnetic plate of the second heating region to cause heating of the ferromagnetic plate of the second heating region.

Determining that a cooking vessel placed on the ferromagnetic plate of the second heating region is to be heated may comprise receiving a user input or sensor input indicating that the cooking vessel placed on the ferromagnetic plate of the second heating region is to be heated.
The method may comprise:
moving the induction coil associated with the first heating region from the first position to the second position only when the induction coil associated with the first heating region is not already used to heat a cooking vessel placed on the first heating region.
The method may comprise:

determining that a cooking vessel is no longer placed on the ferromagnetic plate of the second heating region or is no longer to be heated; and
moving the induction coil associated with the first heating region back from the second position to the first position.

Brief Description of the Drawings

To assist understanding of the present disclosure and to show how embodiments may be put into effect, reference is made by way of example to the accompanying drawings in which:

Figure 1 shows schematically a perspective view of an example of an induction cooker according to an embodiment;
Figure 2 shows schematically a perspective view of the induction cooker of Figure 1 when a cooking vessel is placed on a central heating region;
Figure 3 shows schematically a perspective view of the induction cooker of Figure 1 when a cooking vessel is placed on a central heating region and another cooking vessel is also placed on a peripheral heating region;
Figure 4 shows schematically a perspective view of the induction cooker of Figure 1 when a cooking vessel is removed from a central heating region and a cooking vessel is placed on a peripheral heating region;
Figure 5 shows schematically a side view of the induction cooker of Figure 1;
Figure 6 shows schematically a side view of the induction cooker of Figure 1 when a cooking vessel is placed on a central heating region; and
Figure 7 shows schematically a flow diagram of an example of a method of operating the induction cooker of Figures 1 to 6 in an embodiment.

Detailed Description

Conventional induction cookers comprise a cooking surface with one or more heating regions. Each heating region is associated with a respective induction coil. When a cooking vessel is placed over a heating region, the respective induction coil is fed with an alternating current so as to generate an alternating field and induce a magnetic flux in the cooking vessel. The magnetic flux in the cooking vessel produces eddy currents which, due to the internal resistance of the cooking vessel, heat the cooking vessel.
An issue with conventional inductions cookers is that cooking vessels must be made of or contain ferromagnetic material, such as for example cast iron or some stainless steels. Otherwise, the alternating field generated by the induction coils cannot induce a magnetic flux in the cooking vessels and the cooking vessels cannot be heated by induction.
Accordingly, many cooking vessels, made of for example ceramics, glass, china, plastics, etc. (e.g. mugs, bowls, plates, glasses, etc.) cannot be heated by conventional induction cookers.
Figures 1 to 4 show schematically an example of an induction cooker 2 in an embodiment. The induction cooker 2 comprises a cooking surface including a central heating region 4 and peripheral heating regions 6a, 6b, 6c and 6d.
In the illustrated embodiment, the central heating region 4 may be arranged between the peripheral heating regions 6a, 6b, 6c and 6d at the centre of the cooking surface. Here, the central heating region 4 and the peripheral heating regions 6a, 6b, 6c and 6d have round shapes. The size of the peripheral heating regions 6a and 6d is larger than the size of the peripheral heating regions 6b and 6c. The size of the peripheral heating regions 6a, 6b, 6c and 6d is larger than the size of the central heating region 4. In this way, cooking vessels of various sizes can be heated.
It will be understood that in other embodiments the number, arrangement and/or shape of the heating regions may be different.
The central heating region 4 is formed of or comprises a ferromagnetic plate intended to be heated by induction. For example, the ferromagnetic plate may be made of or contain cast iron or stainless steel. The ferromagnetic plate allows a cooking vessel 10 (shown on Figures 2 and 3) that is not formed of a ferromagnetic material to be placed on the ferromagnetic plate to be heated by conduction (this aspect is further discussed below). The cooking vessel 10 may be made of or contain a material that is sufficiently thermally conductive to allow heat to conduct from the heated ferromagnetic plate of the central heating region 4. The cooking vessel 10 may be made of or contain a glass or ceramic material for example, though other materials may be used.
The peripheral heating regions 6a, 6b, 6c and 6d may be made of non-ferromagnetic material. For example, the peripheral heating regions 6a, 6b, 6c and 6d may be made of or contain thermally conductive material. The peripheral heating regions 6a, 6b, 6c and 6d may typically be made of or contain ceramic or glass material. The peripheral heating regions 6a, 6b, 6c and 6d allow a cooking vessel 16 made of or at least containing some ferromagnetic material placed on the peripheral heating regions 6a, 6b, 6c and 6d to be heated by induction (this aspect is further discussed below).
In the illustrated embodiment, the peripheral heating regions 6a, 6b, 6c and 6d are fixed. The ferromagnetic plate of the central heating region 4 is configured to be moved between an upper position (shown in Figures 1, 4 and 5) and a lower position (shown in Figures 2, 3 and 6). In the upper position, the ferromagnetic plate of the central heating region 4 and the cooking surface extend in the same plane. In the lower position the ferromagnetic plate of the central heating region 4 and the cooking surface extend in different planes.
The induction cooker 2 comprises a biasing member 8, which in this example is a coil spring 8, arranged to elastically bias the ferromagnetic plate of the central heating region 4 toward the upper position. When a cooking vessel 10 is placed on the ferromagnetic plate of the central heating region 4 (as shown in Figures 2, 3 and 5), the spring 8 is compressed and the ferromagnetic plate of the central heating region 4 moves from the upper position to the lower position under the weight of the cooking vessel 10. When the cooking vessel 10 is removed (as shown in Figure 4), the spring 8 extends and the ferromagnetic plate of the central heating region 4 moves back from the lower position to the upper position.
The induction cooker 2 comprises induction coils 12a, 12b, 12c and 12d and rails 14a, 14b, 14c and 14d respectively associated with the peripheral heating regions 6a, 6b, 6c and 6d.
The induction coils 12a, 12b, 12c and 12d are configured to be moved along their rails 14a, 14b, 14c and 14d between a peripheral position (shown in Figures 1, 4 and 5) and a central position (shown in Figures 2, 3 and 6). In the peripheral position the induction coils 12a, 12b, 12c and 12d are arranged to heat a cooking vessel 16 on the peripheral heating regions 6a, 6b, 6c and 6d. In the central position the induction coils 12a, 12b, 12c and 12d are arranged to heat the cooking vessel 10 on the ferromagnetic plate of the central heating region 4. The rail 14a may be non-linear (e.g. curved downwards towards the centre of the induction cooker 2 in this example) so that in the peripheral position a central axes of the induction coils 12a, 12b, 12c and 12d are directed toward the peripheral heating region 6a and in the central position the central axes of the induction coils 12a, 12b, 12c and 12d are directed toward the ferromagnetic plate of the central heating region 4.
In each case, movement of the induction coils 12a, 12b, 12c and 12d along their rails 14a, 14b, 14c and14d may be by virtue of for example an electric motor, with an appropriate linkage and/or pulley and belt arrangement or the like to the induction coil 12a, 12b, 12c and 12d.
Whilst in this example, each induction coil 12a to 12d is movable as described, in other examples, not all induction coils 12a to 12d are movable. In a specific example, only one induction coil 12 is movable as described.
The induction cooker 2 comprises user interface elements 18a, 18b, 18c and 18d to allow a user to indicate whether the cooking vessel 16 is respectively placed on peripheral heating regions 6a, 6b, 6c or 6d and is to be heated. The user interface elements 18a, 18b, 18c and 18d may further allow a user to adjust the heat. The user interface elements 18a, 18b, 18c and 18d may comprise one or more knobs, buttons, tactile screens, etc.
Alternatively or in addition, the induction cooker 2 may comprises sensor elements (not shown) to detect whether the cooking vessel 16 is respectively placed on peripheral heating regions 6a, 6b, 6c or 6d and whether the cooking vessel 16 is to be heated.
Likewise, the induction cooker 2 also comprises a user interface element 20 to allow a user to indicate whether the cooking vessel 10 placed on the ferromagnetic plate of the central heating region 4 is to be heated. The user interface element 20 may further allow a user to adjust the heat. The user interface element 20 may comprise one or more knobs, buttons, tactile screens, etc.
Alternatively or in addition, the induction cooker 2 may comprises sensor elements (not shown) to detect whether the cooking vessel 10 is placed on the ferromagnetic plate of the central heating region 4 and is to be heated.
The induction cooker 2 may selectively feed the induction coils 12a, 12b, 12c and 12d with alternating current. When the induction coils 12a, 12b, 12c and 12d are fed with alternating current, the induction coils 12a, 12b, 12c and 12d generate an alternating field.
When at least one of the induction coils 12a, 12b, 12c or 12d is in a peripheral position the induction coil may induce a magnetic flux in the cooking vessel 16 placed on the corresponding peripheral heating region 6a, 6b, 6c or 6d because the cooking vessel 16 is made of or at least contain some ferromagnetic material. In this way, the cooking vessel 16 placed on the peripheral heating region 6a, 6b, 6c or 6d can be heated by induction.
When at least one of the induction coils 12a, 12b, 12c or 12d is in or moved towards a central position, the induction coil may induce a magnetic flux in the ferromagnetic plate of the central heating region 4 because the ferromagnetic plate of the central heating region 4 is made of or at least contain some ferromagnetic material. In this way, the ferromagnetic plate of the central heating region 4 may be heated by induction and the cooking vessel 10 placed on the central heating region 4 may be heated indirectly by conduction because the cooking vessel is made of or at least contain thermally conductive material.
In this example one or more of the induction coils 12a, 12b, 12c, 12d of the "main", conventional heating regions 6a, 6b, 6c, 6d is moved when required to cause heat to be generated in the ferromagnetic plate of the central heating region 4. This can help to keep down costs as one or more of the induction coils 12a, 12b, 12c, 12d is "re-used" for this purpose. In an alternative, a dedicated induction coil may be provided for the ferromagnetic plate of the central heating region 4. This dedicated induction coil may be located below the cooking surface and below the ferromagnetic plate of the central heating region 4 and interacts with the ferromagnetic plate of the central heating region 4 only when the central heating region 4 has been moved down as described above.
In an example, the induction cooker 2 comprises a processor 22 coupled to a memory 24. The memory 24 comprises instructions which when executed by the processor 22 allow the processor 22 to perform one or more steps of the method of Figure 7.
Figure 7 shows schematically a flow diagram of an example of a method of operating the induction cooker 2.
Initially, no cooking vessel 10 or 16 is placed on the cooking surface of the induction cooker 2 (as shown in Figures 1 and 5). The ferromagnetic plate of the central heating region 4 is in the upper position. The induction coils 12a, 12b, 12c and 12d are in the peripheral positions and are not fed with any alternating current.
In step 100, the processor 22 determines whether a cooking vessel 10 is placed on the ferromagnetic plate of the central heating region 4 and is to be heated. If the processor 22 determines that a cooking vessel 10 is placed on the ferromagnetic plate of the central heating region 4 and is to be heated, the method goes to step 102. If the processor 22 determines that no cooking vessel 10 is placed on the ferromagnetic plate of the central heating region 4 or that a cooking vessel 10 is placed on the ferromagnetic plate of the central heating region 4 but is not to be heated, the method loops back to step 100.
In the example, the user places the cooking vessel 10 on the ferromagnetic plate of the central heating region 4 (as shown in Figures 2 and 6). In response, the ferromagnetic plate of the central heating region 4 automatically moves from the upper position to the lower position. The user uses the user interface element 20 to indicate that the cooking vessel 10 is placed on the ferromagnetic plate of the central heating region 4 and is to be heated and/or this is determined automatically by a sensor detecting a downward movement of the ferromagnetic plate of the central heating region 4.
In step 102 (i.e. a cooking vessel 10 is placed on the ferromagnetic plate of the central heating region 4 and is to be heated), the processor 22 determines whether at least one of the induction coils 12a, 12b, 12c and 12d is not being used to heat any cooking vessel 16 placed on the peripheral heating regions 6a, 6b, 6c and 6d. If the processor 22 determines that at least one of the induction coils 12a, 12b, 12c and 12d is not being used to heat any cooking vessel 16 placed on the peripheral heating regions 6a, 6b, 6c and 6d, the method goes to step 104. If the processor 22 determines that all induction coils 12a, 12b, 12c and 12d are already being used to heat cooking vessels 16 placed on the peripheral heating regions 6a, 6b, 6c and 6d, the method loops back to step 100 or step 102.
In the example, the processor 22 determines that none of the induction coils 12a, 12b, 12c and 12d is being used to heat any cooking vessel 16 placed on the peripheral heating regions 6a, 6b, 6c and 6d.
In step 104 (i.e. at least one of the induction coils 12a, 12b, 12c and 12d is not being used to heat any cooking vessel 16 placed on the peripheral heating regions 6a, 6b, 6c and 6d), the processor 22 causes the at least one of the induction coils 12a, 12b, 12c and 12d to be moved from the peripheral position to the central position (as shown in Figure 2).
For example, the processor 22 causes all of the induction coils 12a, 12b, 12c and 12d to be moved from the peripheral position to the central position.
In step 106, the processor 22 causes the at least one of the induction coils 12a, 12b, 12c and 12d to heat the cooking vessel 10 placed on the ferromagnetic plate of the central heating region 4. That is, the processor 22 causes the at least one of the induction coils 12a, 12b, 12c and 12d to be fed with alternating current to induce a magnetic flux in the ferromagnetic plate of the central heating region 4. In this way, the ferromagnetic plate of the central heating region 4 may be heated by induction and the cooking vessel 10 placed on the central heating region 4 may be heated indirectly by conduction.
In the example, the processor 22 causes all of the induction coils 12a, 12b, 12c and 12d to be fed with alternating current to induce a magnetic flux in the ferromagnetic plate of the central heating region 4.
Subsequently, the user may place a cooking vessel 16 on the peripheral heating region 6b (as shown in Figure 3). The user may then use the user interface elements 16b to indicate that the cooking vessel 16 is placed on the peripheral heating region 6b and is to be heated and/or the presence of the cooking vessel 16 on the peripheral heating region 6b is detected by a sensor. In response, the processor 22 causes the induction coil 12b to be moved back from the central position to the peripheral position.
The user may remove the cooking vessel 10 from the ferromagnetic plate of the central heating region 4 (as shown in Figure 4). The user may then use the user interface element 20 to indicate that the cooking vessel 10 is no longer placed on the ferromagnetic plate of the central heating region 4 or this is determined by a sensor (for example, detecting that the ferromagnetic plate of the central heating region 4 has moved up again). In response, the processor 22 causes the induction coils 12a, 12c and 12d to be moved back from the central position to the peripheral position and stops feeding the induction coils 12a, 12c and 12d with alternating current.
Alternatively, the user may leave the cooking vessel 10 on the ferromagnetic plate of the central heating region 4 (not shown) but may no longer want the cooking vessel 10 to be heated (e.g. the temperature of the cooking vessel 10 is above a threshold). The user may use the user interface element 20 to indicate that the cooking vessel 10 is no longer to be heated. In response, the processor 22 causes the induction coils 12a, 12c and 12d to be moved back from the central position to the peripheral position and stops feeding the induction coils 12a, 12c and 12d with alternating current.
An advantage of the induction cooker 2 over conventional induction cookers is that it allows a larger range of cooking vessels to be used for heating regardless. In particular, it allows heating of cooking vessels that are not made of or contain no ferromagnetic material. In addition, the induction cooker 2 in this example has a minimum number of induction coils which simplifies the overall structure, wiring and cost.
It will be understood that the processor or processing system or circuitry referred to herein may in practice be provided by a single chip or integrated circuit or plural chips or integrated circuits, optionally provided as a chipset, an application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), digital signal processor (DSP), graphics processing units (GPUs), etc. The chip or chips may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry, which are configurable so as to operate in accordance with the exemplary embodiments. In this regard, the exemplary embodiments may be implemented at least in part by computer software stored in (non-transitory) memory and executable by the processor, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware).
The examples described herein are to be understood as illustrative examples of embodiments of the invention. Further embodiments and examples are envisaged. Any feature described in relation to any one example or embodiment may be used alone or in combination with other features. In addition, any feature described in relation to any one example or embodiment may also be used in combination with one or more features of any other of the examples or embodiments, or any combination of any other of the examples or embodiments. Furthermore, equivalents and modifications not described herein may also be employed within the scope of the invention, which is defined in the claims.

Claims

An induction cooker comprising:
a cooking surface comprising a first heating region and a second heating region;

the first heating region being associated with an induction coil for inducing a current in a cooking vessel made at least in part of ferromagnetic material and located in use on the first heating region to heat the cooking vessel;

the second heating region having a ferromagnetic plate which is movable relative to the cooking surface to bring the ferromagnetic plate in proximity to at least one of the induction coil associated with the first heating region and another induction coil so as to allow a current to be induced in the ferromagnetic plate to heat the ferromagnetic plate.
An induction cooker according to claim 1, wherein the ferromagnetic plate of the second heating region is movable relative to the cooking surface between a first position wherein the ferromagnetic plate of the second heating region and the cooking surface extend substantially in the same plane and a second position wherein the ferromagnetic plate of the second heating region and the cooking surface extend in different planes.
An induction cooker according to claim 2, wherein the ferromagnetic plate of the second heating region is biased toward the first position and the ferromagnetic plate of the second heating region is configured to move from the first position to the second position under the weight of a cooking vessel placed on the ferromagnetic plate of the second heating region.
An induction cooker according to any of claims 1 to 3, wherein the induction coil associated with the first heating region is movable between a first position wherein the induction coil is arranged to underlie the first heating region to cause heating of a cooking vessel placed in use on the first heating region and a second position wherein the induction coil is moved closer to the ferromagnetic plate of the second heating region to cause heating of the ferromagnetic plate of the second heating region.
An induction cooker according to claim 4, wherein the induction cooker comprises a rail for supporting the induction coil associated with the first heating region and the induction coil associated with the first heating region is configured to be moved along the rail between the first position and the second position.
An induction cooker according to claim 5, wherein the rail is configured so that in the first position a central axis of the induction coil associated with the first heating region is directed toward the first heating region and in the second position the central axis of the induction coil associated with the first heating region is directed toward the ferromagnetic plate of the second heating region.
An induction cooker according to any of claims 1 to 6, wherein the second heating region is smaller than the first heating region.
An induction cooker according to any of claims 1 to 7, wherein the cooking surface comprises four first heating regions and the second heating region is arranged between the four first heating regions.
An induction cooker according to any of claims 1 to 8, wherein the first heating region is made at least in part of non-ferromagnetic material.
An induction cooker according to any of claims 1 to 9, wherein the first heating region is made at least in part of thermally conductive material.
A method of operating a cooker, the method comprising:
in response to placing a cooking vessel on a second heating region having a ferromagnetic plate, moving the ferromagnetic plate relative to a cooking surface comprising a first heating region and the second heating region to bring the ferromagnetic plate in proximity to at least one of an induction coil associated with the first heating region and another induction coil so as to allow a current to be induced in the ferromagnetic plate to heat the ferromagnetic plate.
A method according to claim 11, comprising:
determining that a cooking vessel placed on the ferromagnetic plate of the second heating region is to be heated; and

moving the induction coil associated with the first heating region from a first position to a second position, wherein in the first position the induction coil associated with the first heating region is arranged to underlie the first heating region to cause heating of a cooking vessel made at least in part of ferromagnetic material placed on the first heating region and in the second position the induction coil is moved closer to the ferromagnetic plate of the second heating region to cause heating of the ferromagnetic plate of the second heating region.
A method according to claim 12, wherein determining that a cooking vessel placed on the ferromagnetic plate of the second heating region is to be heated comprises receiving a user input or sensor input indicating that the cooking vessel placed on the ferromagnetic plate of the second heating region is to be heated.
A method according to claim 12 or claim 13, comprising moving the induction coil associated with the first heating region from the first position to the second position only when the induction coil associated with the first heating region is not already used to heat a cooking vessel placed on the first heating region.
A method according to any one of claims 12 to 14, comprising:
determining that a cooking vessel is no longer placed on the ferromagnetic plate of the second heating region or is no longer to be heated; and

moving the induction coil associated with the first heating region back from the second position to the first position.