Induction hob device, induction hob and method for operating an induction hob device

Abstract

In order to provide an induction hob device which has improved properties with regard to design requirements and / or operational control, the invention proposes an induction hob device comprising: at least one inductor, which has a first winding and a second winding inductively coupled to one another and connected in parallel, for heating at least one item of cookware; and a rectifier unit, downstream of which the windings are connected; wherein a first switching element is connected downstream or upstream of the first winding, and a second switching element or a diode is connected downstream or upstream of the second winding.

Description

[0001] Induction hob device, induction hob and method for operating an induction hob device

[0002] State of the art

[0003] The invention relates to an induction hob device.

[0004] Half-bridge series resonant inverters are already known as circuit topologies for induction cooktops. Single-switch ZVS (zero voltage switching) inverters are also known. Both topologies require a resonant capacitor, which results in particularly high costs, requires a particularly large amount of space, and can compromise reliability.

[0005] The object of the invention is, in particular but not limited to, to provide a generic device with improved properties with regard to design requirements and / or operational control. This object is achieved according to the invention by the features of claim 1, while advantageous embodiments and further developments of the invention can be found in the subclaims.

[0006] Advantages of the invention

[0007] An induction hob device is proposed with at least one inductor for heating at least one cooking utensil, which inductor has a first winding and a second winding which are inductively coupled to one another and connected in parallel, and with a rectifier unit, which is followed by the windings, wherein a first switching element is connected downstream of the first winding and a second switching element or a diode is connected downstream or upstream of the second winding.

[0008] Such a design can provide a high-performance and / or cost-effective circuit topology for an induction cooktop. Improved power control can be achieved. Single-frequency operation can be enabled for the entire output power range of the induction cooktop device. Advantageously, the use of resonant capacitors can be eliminated.

[0009] An "induction hob device" is understood to mean, in particular, at least one part, in particular a subassembly, of an induction hob. It may also include accessory units for the induction hob, such as a sensor unit for externally measuring the temperature of a cooking utensil and / or a food item. In particular, the induction hob device may also comprise the entire induction hob.

[0010] The induction hob device is, in particular, an electronic circuit, preferably for an induction hob. The induction hob device is preferably intended for connection to a voltage source, in particular to an alternating voltage source, preferably to a mains voltage. Preferably, the induction hob device is connected to the voltage source, preferably to the alternating voltage source, at least in one operating state.

[0011] The cooking utensil is designed, for example, as a pot, a pan, a roasting pan, or any other cooking utensil that a person skilled in the art would deem appropriate. When placed on a support plate, in particular a hob plate, of the induction hob, in particular the induction hob device, the cooking utensil can preferably be supplied with energy, at least partially, preferably inductively, at least for heating, in particular by means of the inductor. The inductor is arranged, in particular, below the support plate.

[0012] In this document, position designations such as “below” or “above” preferably refer to an installation position, in particular the mounted state, of the hob, preferably the hob device, unless explicitly described otherwise.

[0013] The rectifier unit is preferably connected downstream of the voltage source, particularly at least in one operating state. The rectifier unit is particularly designed to convert an AC voltage from the voltage source into a DC voltage. It is conceivable for the rectifier unit to be designed as an uncontrolled rectifier or as a controllable rectifier. For example, the rectifier unit comprises a half-wave rectifier, a center-wave rectifier, a bridge rectifier circuit, or the like.

[0014] The first switching element and / or the second switching element are / is, in particular, part of the induction hob device. The first switching element and / or the second switching element are / is preferably designed as power semiconductors. The first switching element and / or the second switching element are / is, for example, designed as MOSFET(s), as IGBT(s), as thyristors, or the like. The first switching element and / or the second switching element are / is preferably switchable, in particular controllable, semiconductor components. The diode is, in particular, part of the induction hob device. The diode is preferably designed as a power semiconductor, in particular as a power diode.

[0015] It is further proposed that the first winding and the second winding be wound in parallel. Advantageously, a particularly strong inductive coupling between the first winding and the second winding can be achieved. Advantageously, a coupling between the first winding and the second winding can be achieved regardless of the size of the cooking utensil to be heated by the inductor. A particularly reliable function of the induction hob device can be achieved. In particular, the first winding and the second winding are wound in parallel at the wire or strand level.

[0016] Furthermore, it is proposed that at least the first switching element be grounded. In particular, insulation requirements, particularly with regard to a driver circuit for the first switching element and / or the second switching element, can be kept low. Advantageously, a particularly simple and / or cost-effective induction hob device can be provided. Preferably, the first switching element and the second switching element are referenced to the same point. Preferably, the second switching element is referenced to ground.

[0017] It is also proposed that the induction hob device have an EMC filter connected upstream of the rectifier unit. This advantageously allows for particularly reliable operation of the induction hob device. The EMC filter (electromagnetic compatibility filter) is preferably connected downstream of the voltage source in at least one operating state. The EMC filter is preferably arranged in the circuitry between the rectifier unit and the voltage source.

[0018] It is further proposed that the rectifier unit comprise a bridge rectifier circuit. Advantageously, both half-waves of the voltage source can be utilized. Advantageously, a particularly low ripple of the output voltage of the rectifier unit can be achieved. Preferably, the rectifier unit comprises a capacitor, in particular a smoothing capacitor. The capacitor is preferably connected downstream of the bridge rectifier circuit. The capacitor is in particular connected in parallel to the first winding and / or the second winding. The capacitor is preferably connected in parallel to the first switching element. The capacitor is preferably connected in parallel to the second switching element or the diode.

[0019] Furthermore, an induction hob, in particular the one already mentioned above, with at least one induction hob device according to the invention is proposed. This can advantageously provide an induction hob with a particularly cost-effective and / or high-performance circuit topology. It is conceivable for the induction hob to have multiple induction hob devices.

[0020] Furthermore, a method for operating an induction hob device, in particular the one already mentioned, with at least one inductor, in particular the one already mentioned, for heating at least one item of cooking utensil, in particular the one already mentioned, which has a first winding, in particular the one already mentioned, and a second winding, in particular the one already mentioned, which are inductively coupled to one another and connected in parallel, and with a rectifier unit, in particular the one already mentioned, which is followed by the windings, wherein a first switching element, in particular the one already mentioned, and a second switching element, in particular the one already mentioned, or a diode, in particular the one already mentioned, is connected downstream of or upstream of the first winding, is proposed.Advantageously, high-performance and / or cost-efficient operation of an induction hob device can be realized. Furthermore, it is proposed that, in particular in at least one exemplary embodiment, at least the first switching element be switched with a duty cycle of 0.5. Advantageously, particularly simple control of the output power of the induction hob device can be achieved via a switching frequency of the switching elements. Preferably, the second switching element is switched with a duty cycle of 0.5. In a further exemplary embodiment, in particular with the first switching element and the diode, the first switching element preferably has a duty cycle with a value of 0 to 0.5.

[0021] Furthermore, it is proposed that the induction hob device, in particular at least in one embodiment, be operated in a boost configuration. Advantageously, the required currents through the switching elements and the windings are halved. Advantageously, the components used must meet particularly low requirements regarding a permissible maximum current. Preferably, a voltage across a load, in particular the cooking utensil, is doubled.

[0022] The induction hob device, the induction hob, and / or the method are not intended to be limited to the application and embodiment described above. In particular, the induction hob device, the induction hob, and / or the method may have a number of individual elements, components, units, and method steps that differs from the number stated herein to fulfill a functionality described herein.

[0023] Further advantages will become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0024] They show:

[0025] Fig. 1 is a schematic representation of an induction hob,

[0026] Fig. 2 is a schematic circuit diagram of an induction hob device of the induction hob,

[0027] Fig. 3 shows a schematic flow of a method for operating the

[0028] Induction hob device, Fig. 4 a graph with time-dependent voltage curves of windings of the induction hob device and a time-dependent current curve through one of the windings,

[0029] Fig. 5 shows a graph with switching frequency-dependent performance curves for different cooking utensils,

[0030] Fig. 6 is a schematic circuit diagram of an induction hob device in an alternative embodiment,

[0031] Fig. 7 shows a graph with a duty cycle-dependent power curve of the induction hob device,

[0032] Fig. 8 shows a graph with time-dependent voltage curves of windings of the induction hob device in the alternative embodiment at a first operating point, and

[0033] Fig. 9 shows a graph with time-dependent voltage curves of the windings at a second operating point.

[0034] Figure 1 shows an induction hob 30a. The induction hob 30a has an induction hob device 10a. The induction hob device 10a is an electronic circuit, preferably for the induction hob 30a. The induction hob device 10a is intended for connection to a voltage source 32a, in particular an AC voltage source, preferably a mains voltage. The induction hob device 10a is connected to the voltage source 32a, preferably to the AC voltage source, at least in one operating state.

[0035] The induction hob device 10a has an inductor 12a for heating at least one cooking utensil (not shown here) (see Figure 2). The cooking utensil is designed, for example, as a pot, a pan, a roasting pan, or as another cooking utensil that appears appropriate to a person skilled in the art. When placed on a support plate 64a, in particular a hob plate, of the induction hob 30a, in particular of the induction hob device 10a, the cooking utensil can be supplied with energy, at least for heating, at least partially, preferably inductively, in particular by means of the inductor 12a. The inductor 12a is arranged below the support plate 64a. The inductor 12a has a first winding 14a and a second winding 16a. The first winding 14a and the second winding 16a are inductively coupled to one another. The first winding 14a and the second winding 16a are connected in parallel.The first winding 14a and the second winding 16a are wound in parallel. The first winding 14a and the second winding 16a are wound in parallel at the wire or strand level.

[0036] The induction hob device 10a has a rectifier unit 18a. The windings 14a, 16a are connected downstream of the rectifier unit 18a. The rectifier unit 18a is connected downstream of the voltage source 32a, particularly at least in one operating state. The rectifier unit 18a is designed to convert an alternating voltage from the voltage source 32a into a direct voltage.

[0037] The rectifier unit 18a is embodied here, for example, as an uncontrolled rectifier. Alternatively, it is conceivable for the rectifier unit 18a to be embodied as a controllable rectifier. The rectifier unit 18a has a bridge rectifier circuit 28a. Alternatively, it is conceivable for the rectifier unit 18a to have a half-wave rectifier, a center-wave full-wave rectifier, or the like.

[0038] The induction hob device 10a has a capacitor 34a, in particular a smoothing capacitor. The capacitor 34a is connected downstream of the rectifier unit 18a, in particular the bridge rectifier circuit 28a. The capacitor 34a is connected in parallel with the first winding 14a and the second winding 16a. The capacitor 34a is connected in parallel with a first switching element 20a and a second switching element 22a.

[0039] A first switching element 20a is connected downstream of the first winding 14a. Alternatively, it is also conceivable for the first switching element 20a to be connected upstream of the first winding 14a. A second switching element 22a is connected downstream of the second winding 16a. Alternatively, it is also conceivable for the second switching element 22a to be connected upstream of the second winding 16a.

[0040] The first switching element 20a and the second switching element 22a are designed as power semiconductors. The first switching element 20a and / or the second switching element 22a are / are designed, for example, as MOSFET(s), IGBT(s), thyristors, or the like. Preferably, the first switching element 20a and the second switching element 22a are referenced to the same point. The first switching element 20a and the second switching element 22a are referenced to ground.

[0041] The induction hob device 10a has an EMC filter 26a. The EMC filter 26a is connected upstream of the rectifier unit 18a. In at least one operating state, the EMC filter 26a is connected downstream of the voltage source 32a. The EMC filter 26a is arranged in circuitry between the rectifier unit 18a and the voltage source 32a.

[0042] Figure 3 shows a schematic sequence of a method for operating the induction hob device 10a.

[0043] In a method step 66a, the first switching element 20a is switched to the conducting state and the second switching element 22a is switched to the non-conducting state. In a further method step 68a, the first switching element 20a is switched to the non-conducting state and the second switching element 22a is switched to the conducting state. At least the first switching element 20a is switched with a duty cycle of 0.5. The second switching element 22a is switched with a duty cycle of 0.5. The induction hob device 10a is operated in a boost configuration.

[0044] Figure 4 shows a graph of a time-dependent voltage curve 36a of the first winding 14a and a time-dependent voltage curve 38a of the second winding 16a. The graph of Figure 4 shows a time-dependent current curve 40a through the first winding 14a. Time, in particular in an arbitrary unit, is plotted on an x-axis of the graph of Figure 4. A voltage, in particular in arbitrary units, and a current, in particular in arbitrary units, are plotted on a y-axis of the graph of Figure 4.

[0045] Figure 5 shows a graph with three switching frequency-dependent power curves 42a, 44a, 46a. An X-axis of the graph in Figure 5 shows a switching frequency in kHz. A Y-axis of the graph in Figure 5 shows an output power in watts. The power curves 42a, 44a, 46a correspond to different loads, in particular cooking utensils. Figures 6 to 9 show a further exemplary embodiment of the invention. The following descriptions and the drawings are essentially limited to the differences between the exemplary embodiments. With regard to components with the same designation, in particular with regard to components with the same reference numerals, reference can generally also be made to the drawings and / or the description of the other exemplary embodiment, in particular Figures 1 to 5. To distinguish the exemplary embodiments, the letter a follows the reference numerals of the exemplary embodiment in Figures 1 to 5.In the embodiments of Figures 6 to 9, the letter a is replaced by the letter b.

[0046] Figure 6 shows an induction hob device 10b. The induction hob device 10b is connected, at least in one operating state, to a voltage source 32b, preferably to the AC voltage source.

[0047] The induction hob device 10b has an inductor 12b for heating at least one cooking utensil (not shown here). The inductor 12b has a first winding 14b and a second winding 16b. The first winding 14b and the second winding 16b are inductively coupled to one another. The first winding 14b and the second winding 16b are connected in parallel.

[0048] The induction hob device 10b has a rectifier unit 18b. The windings 14b, 16b are connected downstream of the rectifier unit 18b. The induction hob device 10b has a capacitor 34b.

[0049] A first switching element 20b is connected downstream of the first winding 14b. Alternatively, it is also conceivable for the first switching element 20b to be connected upstream of the first winding 14b. A diode 24b is connected downstream of the second winding 16b. Alternatively, however, it is also conceivable for the diode 24b to be connected upstream of the second winding 16b. The diode 24b is designed as a power semiconductor, in particular as a power diode.

[0050] The induction hob device 10b has an EMC filter 26b. The EMC filter 26b is connected upstream of the rectifier unit 18b. The rectifier unit 18b has a bridge rectifier circuit 28b. The output power of the induction hob device 10b can be regulated via the duty cycle of the switching element 20b. In particular, the duty cycle has a value of 0 to 0.5.

[0051] Figure 7 shows a graph with a duty cycle-dependent output power of the induction cooktop device 10b. The output power in watts is plotted on the Y-axis of the graph in Figure 7. The duty cycle in percent is plotted on the X-axis of the graph in Figure 7.

[0052] Figure 8 shows a graph with a time-dependent voltage curve 54b of the first winding 14b and a time-dependent voltage curve 52b of the second winding 16b at an exemplary first operating point 48b (see also Figure 7). The graph from Figure 8 shows a time-dependent current curve 56b through the first winding 14b at the first operating point 48b. Time, in particular in an arbitrary unit, is plotted on an x-axis of the graph from Figure 8. A voltage, in particular in arbitrary units, and a current, in particular in arbitrary units, are plotted on a y-axis of the graph from Figure 8.

[0053] Figure 9 shows a graph with a time-dependent voltage curve 58b of the first winding 14b and a time-dependent voltage curve 60b of the second winding 16b at an exemplary second operating point 50b (see also Figure 7). The graph from Figure 9 shows a time-dependent current curve 62b through the first winding 14b at the second operating point 50b. Time, in particular in an arbitrary unit, is plotted on an x-axis of the graph from Figure 9. A voltage, in particular in arbitrary units, and a current, in particular in arbitrary units, are plotted on a y-axis of the graph from Figure 9.

[0054] Reference symbol

[0055] 10 Induction hob device

[0056] 12 Inductor

[0057] 14 windings

[0058] 16 windings

[0059] 18 Rectifier unit

[0060] 20 switching element

[0061] 22 Switching element

[0062] 24 diodes

[0063] 26 EMC filters

[0064] 28 Bridge rectifier circuit

[0065] 30 induction hob

[0066] 32 Voltage source

[0067] 34 Capacitor

[0068] 36 Voltage curve

[0069] 38 Voltage curve

[0070] 40 current curve

[0071] 42 Performance curve

[0072] 44 Performance curve

[0073] 46 Performance curve

[0074] 48 operating point

[0075] 50 operating point

[0076] 52 Voltage curve

[0077] 54 Voltage curve

[0078] 56 current curve

[0079] 58 Voltage curve

[0080] 60 voltage curve

[0081] 62 current curve

[0082] 64 Installation plate 66 Process step

[0083] 68 process steps

Claims

Claims 1. Induction hob device (10a; 10b) with at least one inductor (12a; 12b) for heating at least one cooking utensil, which has a first winding (14a; 14b) and a second winding (16a; 16b) which are inductively coupled to one another and connected in parallel, and with a rectifier unit (18a; 18b) downstream of which the windings (14a, 16a; 14b; 16b) are connected, wherein a first switching element (20a; 20b) is connected downstream of or upstream of the first winding (14a; 14b) and a second switching element (22a) or a diode (24b) is connected downstream of or upstream of the second winding (16a; 16b).

2. Induction hob device (10a; 10b) according to claim 1, characterized in that the first winding (14a; 14b) and the second winding (16a; 16b) are wound in parallel.

3. Induction hob device (10a; 10b) according to claim 1 or 2, characterized in that at least the first switching element (20a; 20b) is referenced to ground.

4. Induction hob device (10a; 10b) according to one of the preceding claims, characterized by an EMC filter (26a; 26b) which is connected upstream of the rectifier unit (18a; 18b).

5. Induction hob device (10a; 10b) according to one of the preceding claims, characterized in that the rectifier unit (18a; 18b) has a bridge rectifier circuit (28a; 28b).

6. Induction hob (30a) with at least one induction hob device (10a; 10b) according to claim 1.

7. Method for operating an induction hob device (10a; 10b) with at least one inductor (12; 12b) for heating at least one cooking utensil, which has a first winding (14a; 14b) and a second winding (16a; 16b) which are inductively coupled to one another and connected in parallel, and with a rectifier unit (18a; 18b) which the windings (14a, 16a; 14b, 16b) are connected downstream, wherein a first switching element (20a; 20b) is connected downstream or upstream of the first winding (14a; 14b), and a second switching element (22a) or a diode (24b) is connected downstream or upstream of the second winding (16a; 16b).

8. The method according to claim 8, characterized in that at least the first switching element (20a; 20b) is switched with a duty cycle of 0.

5.

9. Method according to claim 8 or 9, characterized in that the induction hob device (10a; 10b) is operated in a boost configuration.

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