INDUCTION HEATING DEVICE AND AN ASSOCIATED METHOD
THEREOF

BACKGROUND

[0001] Embodiments of the present invention generally relate to an
induction heating device, and more specifically to a support structure of an induction heating device, for example, an induction cooktop range.

[0002] Induction devices are used for various applications. One such application includes use of induction devices for heating objects.

Such induction heating devices include a plurality of windings to generate an electromagnetic field and a core formed of magnetic material to channelize the magnetic field onto the target heating object. Such induction heating devices also include a heat sink or a heat spreader plate for dissipating the thermal energy generated from the induction device. The induction heating devices may include a plurality of configurations in which the windings, the core, and the heat sink are coupled together to form the induction heating device.

[0003] Induction heating devices further include a support plate disposed
between the coil assembly and the heat sink or the heat spreader plate. The support plate provides contact between the coil assembly and the heat sink and also supports the coil assembly. The conventional support plate generates additional losses and affects the magnetic performance of the induction coil assembly.

[0004] There is a need for an enhanced induction heating device.

DRAWINGS

[0005] These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

273680-1

[0006] FIG. 1 is a sectional view of an induction heating device, for example, an induction cooktop range, in accordance with an exemplary embodiment;

[0007] FIG. 2 is a diagrammatical representation of a non-uniform support structure of an induction heating device in accordance with another exemplary embodiment;

[0008] FIG. 3 is a diagrammatical representation of a non-uniform support structure of an induction heating device in accordance with yet another exemplary embodiment;

[0009] FIG. 4 is a diagrammatical representation of a non-uniform
support structure of an induction heating device in accordance with yet another exemplary embodiment; and

[0010] FIG. 5 is a flow diagram illustrating exemplary steps involved in a
method of manufacturing an induction heating device in accordance with an exemplary embodiment.

DETAILED DESCRIPTION

[0011] Embodiments of the present invention disclose an induction heating device. The induction heating device includes a non-uniform support structure disposed on a heat spreader plate. A plurality of ferromagnetic blocks is spaced apart from each other and disposed on the non-uniform support structure. An induction coil is disposed on the plurality of ferromagnetic blocks. A support top is disposed above and spaced apart from the induction coil by a dielectric material, for example, air. The non-uniform support structure provides thermal contact between the induction coil and the heat spreader plate and facilitates to dissipate the heat generated by the induction coil to the heat spreader plate. Further, the non-uniform support structure provides a high reluctance path to the magnetic flux lines and acts as an lectromagnetic shield. In one embodiment, a
method of manufacturing the induction heating device is disclosed. In another embodiment, a method for operating the induction heating device is disclosed.

[0012] FIG. 1 is a sectional view of an induction heating device 10, for example, an induction cooktop range, in accordance with an exemplary embodiment of the present invention.

The induction heating device 10 includes a support top 12 disposed above and spaced apart from an induction coil 14 by a dielectric material 16, for example, air. In one embodiment, the support top 12 is a glass top.

The induction coil 14 may be made of an electrically conducting material such as copper.

The induction coil 14 may include a plurality of coil sections (not shown) having different radius. Each coil section may include a plurality of windings. In one embodiment, the support top 12 has a thickness of 5mm and the induction coil 14 has a thickness of 2mm. The dielectric material 16 may be around 3mm. A vessel 17 to be heated is disposed on the support top 12. The induction heating device 10 is configured to receive electric power from a power supply source (not shown) and the induction coil 14 is configured to generate a magnetic flux using the power received from the power supply source.

[0013] In the illustrated embodiment, the induction coil 14 is disposed on
a plurality of ferromagnetic blocks 18 spaced apart from each other. The plurality of ferromagnetic blocks 18 forms a magnetic core of the induction heating device 10. The ferromagnetic blocks 18 of different shapes may be fabricated to form the magnetic core of the desired configuration. The plurality of ferromagnetic blocks 18 is disposed on a non-uniform support structure 20. In the illustrated embodiment, the non-uniform support structure 20 includes a plurality of support blocks 22 disposed spaced apart from each other. Each ferromagnetic block 18 is supported by a corresponding support block 22. The non-uniform support structure 20 may be made of an electrically conducting, thermally conducting, and non-magnetic material. In one embodiment, the electrically conducting, thermally conducting, and non-magnetic material includes aluminum. In another embodiment, the electrically conducting, thermally conducting, and non-magnetic material includes a non-metal with conducting filler particles or fibers such as graphite fibers, carbon nanotubes, or the like. In yet another embodiment, the electrically conducting, thermally conducting, and non-magnetic material includes nano fiber based polymer metal composites, for example, indium composites. In yet another embodiment, the electrically conducting, thermally conducting, and non-magnetic material includes grease, phase change materials, gel, liquid metal alloy, solder, or the like. Each ferromagnetic block 18 and each support block 22 may have a thickness of 7.5mm, for example. The induction coil 14 is configured to generate a magnetic flux in the induction heating device 10.

[0014] The non-uniform support structure 20 is disposed on a heat spreader plate 24. The heat spreader plate 24 may be made of a material such as aluminum and may have thickness of 7.5mm, for example. The heat spreader plate 24 is used to dissipate thermal energy generated from the induction coil 14 to the environment. The plurality of ferromagnetic blocks 18 is configured to provide a low reluctance path for magnetic flux that is generated below the induction coil 14. Hence, the plurality of ferromagnetic blocks 18 facilitates to reduce losses on the non-uniform support structure 20 and the heat spreader plate 24. The heat spreader plate 24 is disposed on an insulation sheet 26. It should be noted herein that the term "insulation sheet" refers to a sheet that is made of a thermally insulating material. An electronics unit (not shown) for the induction coil 14 is disposed below the insulation sheet 26. The heat spreader plate 24 and the nsulation sheet 26 serve as a shield to protect the electronics unit from the heat generated by the induction coil 14.

[0015] In one embodiment, the induction coil 14 is coupled to an AC power source via an input filter (not shown). The input filter 720 is configured to filter harmonics from the power signals received from the power source. Further, AC power received from the power source may be then converted to DC power via a rectifier. The DC power may be further converted to an input AC power via an inverter at a required voltage and frequency for generating a magnetic flux and heating the vessel 17. The heat generated in the induction coil 14 due to current flow, is dissipated to the heat spreader plate 24 via the plurality of ferromagnetic blocks 18 and the non-uniform support structure 20. In an alternative embodiment, a DC power source may also be used to provide DC power to the induction heating device 10.

[0016] In accordance with the exemplary embodiment, the non-uniform support structure 20 has reduced material compared to conventional support structure. The exemplary non-uniform support structure 20 reduces the effects associated with additional losses and enhances the magnetic performance of the induction coil 14 while still maintaining the required thermal performance. Further, the non-uniform support structure 20 ensures proper thermal contact between the plurality of ferromagnetic blocks 18 and the heat spreader plate 24 to dissipate the heat generated due to resistive losses in the induction coil 14 and radiative losses from other components of the induction heating device 10. The exemplary design ensures low induction of eddy currents in the non-uniform support structure 20.

[0017] Referring to FIG. 2, a diagrammatical representation of a non- uniform support structure 28 of an induction heating device in accordance with another exemplary embodiment is shown. The non-uniform support structure 28 includes a central portion 30 and a plurality of projections 32 spaced part from each other and protruding from the central portion 30. In the illustrated embodiment, the central portion 30 has an annular shaped cross-section with a central opening 34 and each projection 32 has a rectangular shaped cross-section. In other embodiments, the central portion 30 and the plurality of projections 32 may have a different cross-section depending on the application.

Although six projections 32 are shown, in other embodiments, the number of projections may vary.

The length of each projection 32, spacing between the projections 32 may also vary. The plurality of projections 32 supports a plurality of ferromagnetic blocks (not shown) of the induction heating device.

[0018] Referring to FIG. 3, a diagrammatical representation of a non- uniform support structure 36 of an induction heating device in accordance with yet another embodiment is shown.

The non-uniform support structure 36 includes a plate 38 having a plurality of perforations 40 formed in a predefined pattern. In the illustrated embodiment, the plurality of perforations 40 is formed along a plurality of straight lines intersecting with each other at a center of the plate. Although an annular plate 38 is shown, in other embodiments, the plate 38 may have a different cross-section. In the illustrated embodiment, each perforation 40 has a circular cross-section. In another embodiment, the perforation 40 may have a different cross-section. Although five lines of perforations 40 are shown, in other embodiments, the number of lines of perforations 40, spacing between the perforations 40, and the number of perforations 40 may vary.

[0019] In the illustrated embodiment, the plate 38 includes a plurality of sectors 42 formed between the lines of perforations 40. Each sector 42 is used for supporting a corresponding ferromagnetic block 44 of the induction heating device. In other embodiments, the plurality of perforations 40 may be formed in another predefined pattern.

[0020] Referring to FIG. 4, a diagrammatical representation of a non- uniform support structure 46 of an induction heating device in accordance with yet another exemplary embodiment is shown. The non-uniform support structure 46 includes an inner portion 48 with a central opening 49, an outer portion 50, and a plurality of projections 52 spaced part from each other and extending between the inner portion 48 and the outer portion 50. The non-uniform support structure 46 further includes a plurality of slots 54 formed between the inner portion 48 and the outer portion 50. Specifically, each projection 52 and slot 54 is formed alternately between the inner portion 48 and the outer portion 50. In the illustrated embodiment, the inner portion 48, the outer portion 50 have an annular shaped cross-section, and each rojection 52 has a rectangular shaped cross-section.

[0021] In other embodiments, the inner portion 48, the outer portion 50,the plurality of projections 52 and slots 54 may have a different cross-section depending on the application. Although six projections 52 and slots 54 are shown, in other embodiments, the number of projections 52 and slots 54 may vary. The length of each projection 52, spacing between the projections 52 may also vary. The plurality of projections 52 supports a plurality of ferromagnetic blocks (not shown) of the induction heating device.

[0022] In accordance with the exemplary embodiments discussed herein, the non-uniform support structure (aluminum blocks or slotted design) has reduced material compared to a conventional support structure. The exemplary design of the non-uniform support structure ensures proper thermal management of the induction coil. The non-uniform structure facilitates proper thermal contact of the plurality of ferromagnetic bars to the heat spreader plate. Further such a design results in reduced losses and enhanced power transfer capability and efficiency in the induction heating device.

[0023] Referring to FIG. 5, a flow diagram illustrating exemplary steps involved in method of manufacturing an induction heating device in accordance with an exemplary embodiment is shown. The method involves disposing a support top above and spaced apart from an induction coil by a dielectric material, for example, air 58. The support top enables to support a vessel to be heated. The induction heating device is configured to receive electric power from a power supply source and the induction coil is configured to generate a magnetic flux using the power received from the power supply source.
[0024] The method further involves disposing the induction coil on a plurality of ferromagnetic blocks spaced apart from each other 60. The method further involves disposing the plurality of ferromagnetic blocks on a non-uniform support structure 62. In one embodiment, the non-uniform support structure is fabricated by forming a plurality of support blocks disposed spaced apart from each other. Each ferromagnetic block is supported by a corresponding support block. The non-uniform support structure may be made of an electrically conducting, thermally conducting, and non-magnetic material. In another embodiment, the non-uniform support structure is fabricated by forming a central portion and a plurality of projections spaced part from each other and protruding from the central portion. In one such specific embodiment, the non-uniform support structure is fabricated by forming a central portion having an annular shaped cross-section with a central opening and each projection having a rectangular shaped cross-section.

[0025] In yet another embodiment, the non-uniform support structure is fabricated by forming a plate having a plurality of perforations formed in a predefined pattern. In one such specific embodiment, the plurality of perforations is formed along a plurality of straight lines intersecting with each other at a center of the plate. The plate includes a plurality of sectors formed between the lines of perforations. The plate is disposed in such a way that each sector supports a corresponding ferromagnetic block of the induction heating device.

[0026] In yet another embodiment, the non-uniform support structure is fabricated by forming an inner portion with a central opening, an outer portion, and a plurality of projections spaced part from each other and extending between the inner portion and the outer portion. Further, a plurality of slots is formed between the inner portion and the outer portion.

Specifically, each projection and slot is formed alternately between the inner portion and the outer portion. In one such specific embodiment, the non-uniform support structure is fabricated by forming the inner portion, and the outer portion having an annular shaped cross-section, and each projection having a rectangular shaped cross-section.

[0027] The method further involves disposing the non-uniform support structure on a heat spreader plate 64. The heat spreader plate is used to dissipate thermal energy generated from the induction coil to the environment. The method further involves disposing the heat spreader plate on an insulation sheet 66. As discussed earlier, the term "insulation sheet" refers to a sheet that is made of a thermally insulating material. The heat spreader plate and the insulation sheet serve as a shield to protect the electronics unit disposed below the insulation sheet from the heat generated by the induction coil.

[0028] While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

CLAIMS

I/We claim

1. An induction heating device comprising:
a heat spreader plate;

a non-uniform support structure disposed on the heat spreader plate;

a plurality of ferromagnetic blocks spaced apart from each other and disposed on the non-uniform support structure;

an induction coil disposed on the plurality of ferromagnetic blocks; and

a support top disposed above and spaced apart from the induction coil.

2. The induction heating device of claim 1, wherein the non-uniform support structure comprises a central portion and a plurality of projections spaced part from each other and protruding from the central portion.

3. The induction heating device of claim 2, wherein the central portion has an annular shaped cross-section and each projection has a rectangular shaped cross-section.

4. The induction heating device of claim 1, wherein the non-uniform support structure comprises a plurality of perforations formed in a predefined pattern.

5. The induction heating device of claim 4, wherein the plurality of perforations is formed along a plurality of straight lines intersecting with each other.

6. The induction heating device of claim 1, wherein the non-uniform support structure comprises an inner portion, an outer portion, and a plurality of projections spaced part from each other and extending between the inner portion and the outer portion.

7. The induction heating device of claim 6, wherein the non-uniform support structure further comprises a plurality of slots formed between the inner portion and the outer portion, wherein each projection and slot are formed alternately.

8. The induction heating device of claim 6, wherein the inner portion, the outer portion have an annular shaped cross-section, and each projection has a rectangular shaped cross-section.

9. The induction heating device of claim 1, wherein the non-uniform support structure comprises a plurality of support blocks spaced apart from each other.

10. The induction heating device of claim 1, wherein the non-uniform support structure is made of an electrically conducting, thermally conducting, and non-magnetic material.

11. A method comprising:

disposing a non-uniform support structure on a heat spreader plate;

disposing a plurality of ferromagnetic blocks spaced apart from each other and on the non-uniform support structure;

disposing an induction coil on the plurality of ferromagnetic blocks; and disposing a support top above and spaced part from the induction coil.

12. The method of claim 11, further comprising forming the non-uniform support structure comprising a central portion and a plurality of projections spaced part from each other and protruding from the central portion.

13. The method of claim 12, further comprising forming the central portion having an annular shaped cross-section and each projection having a rectangular shaped cross-section.

14. The method of claim 11, further comprising forming the non-uniform support structure comprising a plurality of perforations formed in a predefined pattern.

15. The method of claim 14, further comprising forming the plurality of perforations along a plurality of straight lines intersecting with each other.

16. The method of claim 11, further comprising forming the non¬uniform support structure comprising an inner portion, an outer portion, and a plurality of projections spaced part from each other and extending between the inner portion and the outer portion.

17. The method of claim 16, further comprising forming a plurality of slots between the inner portion and the outer portion, wherein each projection and slot are formed alternately.

18. The method of claim 17, further comprising forming the inner portion, the outer portion having an annular shaped cross-section, and each projection having a rectangular shaped cross-section.

19. The method of claim 11, further comprising forming the non¬uniform support structure comprising a plurality of support blocks spaced apart from each other.

20. A method for operating an induction heating device, the method comprising:
transmitting power to an induction coil disposed on a plurality of ferromagnetic blocks; heating the induction coil; and
dissipating heat from the induction coil to a heat spreader plate via the plurality of ferromagnetic blocks and a non-uniform support structure; wherein the plurality of ferromagnetic blocks are disposed on the heat spreader plate via the non-uniform support structure.