DOMESTIC APPLIANCE DEVICE

Abstract

A household appliance device includes a control unit which is designed to control an induction target repetitively with a switching frequency and to supply the induction target with energy. The control unit is designed to modulate in an operating state through frequency modulation the switching frequency within a modulation period which corresponds to an integer multiple of a half period of a mains AC voltage.

Claims

1-12. (canceled)

13. A household appliance device, comprising a control unit designed to control an induction target repetitively with a switching frequency and to supply the induction target with energy, said control unit designed to modulate in an operating state through frequency modulation the switching frequency within a modulation period which corresponds to an integer multiple of a half period of a mains AC voltage.

14. The household appliance device of claim 13, constructed in a form of a cooking appliance device.

15. The household appliance device of claim 13, wherein the modulation period comprises at least two modulation intervals which each correspond to an integer multiple of a half period of a mains AC voltage.

16. The household appliance device of claim 15, wherein the at least two modulation intervals are different from one another.

17. The household appliance device of claim 13, wherein in the operating state the control unit modulates the switching frequency using a predefined modulation profile.

18. The household appliance device of claim 17, wherein the modulation profile is able to be described by a substantially continuous mathematical function.

19. The household appliance device of claim 17, wherein the modulation profile within the modulation period has a path which is linear at least in one portion.

20. The household appliance device of claim 17, wherein the modulation profile within the modulation period has a path which is exponential at least in one portion.

21. The household appliance device of claim 17, wherein the modulation profile within the modulation period is mirror-symmetrical at least in one portion.

22. The household appliance device of claim 17, wherein the control unit is designed to vary the modulation profile using a parameter relating to the induction target.

23. The household appliance device of claim 22, wherein the parameter comprises an electrical conductance value of the induction target.

24. The household appliance device of claim 13, wherein in the operating state the control unit additionally modulates through a further frequency modulation the switching frequency within an intermediate modulation period which corresponds to a maximum of the half period of the mains AC voltage.

25. A household appliance comprising a household appliance device, said household appliance device comprising a control unit which designed to control an induction target repetitively with a switching frequency and to supply the induction target with energy, said control unit designed to modulate in an operating state through frequency modulation the switching frequency within a modulation period which corresponds to an integer multiple of a half period of a mains AC voltage.

26. The household appliance of claim 25, wherein the household appliance device is embodied as a cooking appliance device.

27. A method for operating a household appliance device, said method comprising: controlling an induction target by a switching frequency; and modulating the switching frequency through frequency modulation within a modulation period which corresponds to an integer multiple of a half period of a mains AC voltage.

28. The method of claim 27 for operating a cooking appliance device as the household appliance device.

29. The method of claim 27, wherein the switching frequency is modulated using a predefined modulation profile.

30. The method of claim 29, further comprising varying the modulation profile using a parameter relating to the induction target.

31. The method of claim 27, wherein the parameter comprises an electrical conductance value of the induction target.

32. The method of claim 27, further comprising additionally modulating through a further frequency modulation the switching frequency within an intermediate modulation period which corresponds to a maximum of the half period of the mains AC voltage.

Description

[0027] In the drawing:

[0028] FIG. 1 shows a schematic view of a household appliance comprising a household appliance device comprising an induction target and a control unit;

[0029] FIG. 2 shows a schematic electrical circuit diagram of the household appliance comprising the household appliance device,

[0030] FIG. 3 shows a schematic diagram for showing a modulation period within which the control unit modulates a switching frequency,

[0031] FIG. 4 shows a schematic diagram for showing a modulation profile, the control unit modulating the switching frequency thereby,

[0032] FIG. 5 shows a further exemplary embodiment of a modulation profile, a control unit of a household appliance device modulating a switching frequency thereby, in a schematic diagram,

[0033] FIG. 6 shows a further exemplary embodiment of a modulation profile, a control unit of a household appliance device modulating a switching frequency thereby, in a schematic diagram,

[0034] FIG. 7 shows a further exemplary embodiment of a modulation profile, the control unit of a household appliance device modulating a switching frequency thereby, in two schematic diagrams and

[0035] FIG. 8 shows a further exemplary embodiment of a modulation profile, a control unit of a household appliance device modulating a switching frequency thereby, in two schematic diagrams.

[0036] FIG. 1 shows a household appliance 40a comprising a household appliance device 10a. The household appliance 40a is configured as an induction hob. The household appliance device 10a has a control unit 12a and an induction target 14a.

[0037] The control unit 12a is provided to control the induction target 14a repetitively with a switching frequency 16a (see FIG. 3) and to supply said induction target with energy.

[0038] FIG. 2 shows a schematic electrical circuit diagram of the household appliance 40a. The household appliance 40a is connected to a mains AC voltage source 34a. The mains AC voltage source 34a provides a mains AC voltage 22a or a mains AC current 36a with a period 46a. The household appliance 40a has an EMC filter unit 38a which is electrically conductively connected to the mains AC voltage source 34a. The household appliance device has a rectifier unit 42a which is electrically conductively connected via the EMC filter unit 38a to the mains AC voltage source 34a. The rectifier unit 42a is provided to convert the mains AC voltage 22a into a periodically pulsing DC voltage 44a, the period thereof corresponding to a half period 20a of the mains AC voltage 22a.

[0039] The control unit 12a is provided to control the induction target 14a repetitively with a switching frequency 16a and to supply said induction target with energy. The control unit 12a comprises an inverter unit 48a. The inverter unit 48a is electrically conductively connected to the rectifier unit 42a of the household appliance 40a. In an operating state of the household appliance device 10a the inverter unit 48a of the control unit 12a converts the AC voltage 44a provided by the rectifier unit 12a of the household appliance 40a within a plurality of successive switching processes, which in each case last for a switching period 52a, into a supply voltage 50a with the switching frequency 16a. In an operating state of the household appliance device 10a the control unit 12a supplies the induction target 14a with electrical energy in the form of a supply current 54a.

[0040] In FIG. 3 a diagram is shown for a schematic view of a modulation period 18a. A time is plotted on an X-axis 56a of the diagram. The switching frequency 16a and the supply current 54a are plotted on a Y-axis 58a. In the operating state the control unit 12a modulates the switching frequency 16a within a modulation period 18a by means of a frequency modulation. The modulation period 18a corresponds to an integer multiple of the half period 20a of the mains AC voltage 22a. Averaged over the modulation period 28a the switching frequency 16a corresponds to an average switching frequency 60a.

[0041] FIG. 4 shows a diagram for showing a modulation profile 28a within the modulation period 18a. A time is plotted on an X-axis 62a of the diagram. The switching frequency 16a is plotted on a Y-axis 64a.

[0042] The modulation period 18a comprises a plurality of successive modulation intervals 24a, 26a which in each case correspond to an integer multiple of the half period 20a of the mains AC voltage 22a. In FIG. 4 two of the modulation intervals 24a, 26a are illustrated by way of example. Within the modulation interval 24a the switching frequency 16a rises. Within the modulation interval 26a the switching frequency 16a falls.

[0043] In the operating state the control unit 12a modulates the switching frequency 16a using the predefined modulation profile 28a. The modulation profile 28a is able to be described by a substantially continuous mathematical function. The modulation profile 28a within the modulation period 18a has a path which is linear at least in some portions. Within a first portion 68a of the modulation period 18a, the modulation profile 28a has a linear and substantially continuous path with an increasing switching frequency 16a. Within a second portion 70a the modulation profile 28a has a linear and substantially continuous path with a reducing switching frequency 16a. The modulation profile 28a is mirror-symmetrical in at least some portions. In the present case, the modulation profile 28a is mirror-symmetrical relative to an axis of symmetry 66a so that the path of the modulation profile 28a in the first portion 68a, by reflection on the axis of symmetry 66a, produces the path of the modulation profile 28a in the second portion 70a.

[0044] After the elapse of the modulation period 18a this is repeated again and the control unit 12a modulates the switching frequency 16a again using the modulation profile 28a.

[0045] In a method for the operation of the household appliance device 10a, the switching frequency 16a is modulated within the modulation period 18a which corresponds to an integer multiple of a half period 20a of the mains AC voltage 22a, by means of the frequency modulation.

[0046] Four further exemplary embodiments of the invention are shown in FIGS. 5 to 8. The following descriptions are substantially limited to the differences between the exemplary embodiments, wherein relative to components, features and functions remaining the same, reference can be made to the description of the exemplary embodiment of FIGS. 1 to 4. For differentiating between the exemplary embodiments the letter a in the reference numerals of the exemplary embodiment in FIGS. 1 to 4 is replaced by the letters b to e in the reference numerals of the exemplary embodiments of FIGS. 5 to 8. Relative to components denoted the same, in particular relative to components with the same reference numerals, in principle reference can also be made to the drawings and/or the description of the exemplary embodiment of FIGS. 1 to 4.

[0047] FIG. 5 shows a diagram for showing a modulation profile 28b which is used by a control unit 12b of a household appliance device 10b for a frequency modulation of a switching frequency 16b. A time is plotted on an X-axis 62b of the diagram. A switching frequency 16b is plotted on a Y-axis 64b of the diagram.

[0048] The household appliance device 10b substantially differs from the household appliance device 10a of the preceding exemplary embodiment regarding the modulation profile 28b used by the control unit 12b for the frequency modulation. In an operating state of the household appliance device 10b, the control unit 12b modulates the switching frequency 16b using the modulation profile 28b by means of the frequency modulation within a modulation period 18b which corresponds to an integer multiple of a half period 20b of a mains AC voltage 22b.

[0049] The modulation profile 28b is able to be described by an at least substantially continuous mathematical function. The modulation profile 28b within the modulation period 18b has a path which is linear at least in some portions. Within a first sub-portion 72b of a first portion 68b of the modulation period 18b, the modulation profile 28b has a linear and substantially continuous path with an increasing switching frequency 16b. Within a second sub-portion 74b of the first portion 68b of the modulation period 18b, the modulation profile 28b has a linear and substantially continuous path with a flatter rise in the switching frequency 16b relative to the first sub-portion 72b. Within a third sub-portion 76b of the first portion 68b of the modulation period 18b, the modulation profile 28b has a linear and substantially continuous path with a flatter rise of the switching frequency 16b relative to the second sub-portion 74b.

[0050] The modulation profile 28b is mirror-symmetrical at least in some portions. In the present case, the modulation profile 28b is mirror-symmetrical relative to an axis of symmetry 66b so that the path of the modulation profile 28b in the first portion 68b, by reflection on the axis of symmetry 66b, produces a path of the modulation profile 28b in a second portion 70b.

[0051] FIG. 6 shows a diagram for showing a modulation profile 28c which is used by a control unit 12c of a household appliance device 10c for a frequency modulation of a switching frequency 16c. A time is plotted on an X-axis 62c of the diagram. A switching frequency 16c is plotted on a Y-axis 64c of the diagram.

[0052] The household appliance device 10c substantially differs from the household appliance devices 10a and 10b of the preceding exemplary embodiments regarding the modulation profile 28c used by the control unit 12c for the frequency modulation. In an operating state of the household appliance device 10c, the control unit 12c modulates the switching frequency 16c using the modulation profile 28c by means of the frequency modulation within a modulation period 18c which corresponds to an integer multiple of a half period 20c of a mains AC voltage 22c.

[0053] The modulation profile 28c is able to be described by an at least substantially continuous mathematical function. The modulation profile 28c within the modulation period 18c has a path which is exponential at least in some portions. Within a first portion 68c of the modulation period 18c, the modulation profile 28c has a substantially continuous path with an exponentially increasing switching frequency 16b. Within a second portion 70c of the modulation period 18c, the modulation profile 28c has a substantially continuous path with an exponentially reducing switching frequency 16c.

[0054] The modulation profile 28c is mirror-symmetrical at least in some portions. In the present case, the modulation profile 28c is mirror-symmetrical relative to an axis of symmetry 66c so that the path of the modulation profile 28c in the first portion 68c, by reflection on the axis of symmetry 66c, produces a path of the modulation profile 28c in a second portion 70c.

[0055] FIG. 7 shows two diagrams for showing a modulation profile 28d which is used by a control unit 12d of a household appliance device 10d for a frequency modulation of a switching frequency 16d. A time is plotted on an X-axis 62d of a lower diagram. A switching frequency 16d is plotted on a Y-axis 64d of the lower diagram. A time is plotted on an X-axis 78d of an upper diagram. A power 82d is plotted on a Y-axis 80d of the upper diagram.

[0056] The household appliance device 10d substantially differs from the household appliance devices 10a-c of the previous exemplary embodiments regarding the modulation profile 28d used by the control unit 12d for the frequency modulation. In an operating state of the household appliance device 10b, the control unit 12d controls an induction target 14d of the household appliance device 10d with the switching frequency 16d and modulates this switching frequency using the modulation profile 28d by means of the frequency modulation within a modulation period 18d which corresponds to an integer multiple of a half period 20d of a mains AC voltage 22d.

[0057] The control unit 12d is provided to vary the modulation profile 28d using at least one parameter 30d relating to the induction target 14d. In the present exemplary embodiment, the parameter 30d relating to the induction target 14d is a target power which is set by a user and which is intended to be provided by the induction target 14d. A general path of the modulation profile 28d is at least substantially continuous, linear in some portions, and can be observed as an inverse of a general path of the modulation profile 28b (see FIG. 5). Using the parameter 30d relating to the induction target 14d, in an operating state the control unit 12d varies a frequency value range 84d of the modulation profile 28d such that the path of the power 82d shown in the upper diagram is produced. Due to the frequency modulation of the switching frequency 16d, the power 82d changes and has in some portions an excess 86d and in some portions a deficit 88d so that when observed over the modulation period 18d the power 82d corresponds on average to the target power set by the user.

[0058] FIG. 8 shows two diagrams for showing a modulation profile 28e which is used by a control unit 12e of a household appliance device 10e for a frequency modulation of a switching frequency 16e. A time is plotted on an X-axis 62e of a lower diagram. The switching frequency 16e is plotted on a Y-axis 64e of the lower diagram. A time is plotted on an X-axis 78e of an upper diagram. An electrical conductance value 90e is plotted on a Y-axis 80e of the upper diagram.

[0059] The household appliance device 10e differs from the household appliance device 10d of the preceding exemplary embodiment regarding a parameter 30e relating to an induction target 14e which the control unit 12e uses as a basis for a variation of the modulation profile 28e. The parameter 30e comprises at least one electrical conductance value of the induction target 14e. In the present case, the parameter 30e relating to the induction target 14e is an average real conductance value of the induction target 14e. Using the parameter 30e relating to the induction target 14e, in an operating state the control unit 12e varies the modulation profile 28e such that the path of the electrical conductance value 90e shown in the upper diagram is produced. Due to the frequency modulation of the switching frequency 16e the electrical conductance value 90e changes and has in some portions an excess 86e and in some portions a deficit 88e. The control unit 12d varies the modulation profile 28e such that the electrical conductance value 90e on average is constant when observed over the modulation period 18e.

[0060] In an operating state of the household appliance device 10e, the control unit 12e controls an induction target 14e of the household appliance device 10e with the switching frequency 16e and modulates this switching frequency using the modulation profile 28e by means of the frequency modulation within a modulation period 18e which corresponds to an integer multiple of a half period 20e of a mains AC voltage 22e.

[0061] The household appliance device 10e also differs from the household appliance device 10a-d in that in the operating state the control unit 12e modulates the switching frequency 16e additionally within an intermediate modulation period 32e which corresponds to a maximum of the half period 20e of the mains AC voltage 22e, by means of at least one further frequency modulation. In an operating state, in addition to the above-described frequency modulation using the modulation profile 28e, the control unit 12e varies the switching frequency 16e briefly within the intermediate modulation period 32e and namely within the half period 20e of the mains AC voltage 22e, using the intermediate modulation profile 92e shown in FIG. 8, in order to prevent an occurrence of flicker.

TABLE-US-00001 Reference numerals 10 Household appliance device 12 Control unit 14 Induction target 16 Switching frequency 18 Modulation period 20 Half period 22 Mains AC voltage 24 Modulation interval 26 Further modulation interval 28 Modulation profile 30 Parameter 32 Intermediate modulation period 34 Mains AC voltage source 36 Mains AC current 38 EMC filter unit 40 Household appliance 42 Rectifier unit 44 AC voltage 46 Period 48 Inverter unit 50 Supply voltage 52 Switching period 54 Supply current 56 X-axis 58 Y-axis 60 Average switching frequency 62 X-axis 64 Y-axis 66 Axis of symmetry 68 First portion 70 Second portion 72 First sub-portion 74 Second sub-portion 76 Third sub-portion 78 X-axis 80 Y-axis 82 Power 84 Frequency value range 86 Excess 88 Deficit 90 Electrical conductance value 92 Intermediate modulation profile