Induction cooking appliance

Abstract

The invention relates to an induction cooking appliance device (10a-d), in particular an induction hob device, with an inverter unit (12a-d) which has at least three inverter switching elements (14a-d, 16a-d, 18a-d, 82b-d, 88c) arranged electrically in series with each other, and with a snubber unit (20a-d) associated with the inverter unit (12a-d) which has a plurality of snubber capacitors (22a-d, 24a-d, 26a-d, 28a-d, 84b-d, 86b-c, 90c, 92c). In order to provide generic devices with improved efficiency characteristics, it is proposed that at least one of the snubber capacitors (22a-d, 24a-d, 26a-d, 28a-d, 84b-d, 86b-c, 90c, 92c) is arranged electrically in parallel to exactly two inverter switching elements (14a-d, 16a-d, 18a-d; 82b-d, 88c) of the inverter unit (12a-d).

Description

[0001] The invention relates to an induction cooking appliance according to the preamble of claim 1.

[0002] Induction cooktops with inverters are already known in the art, comprising three or more inverter switching elements connected electrically in series to control two or more inductors. In such inverter switching arrangements, the number of inverter switching elements can be reduced compared to the full or half-bridge topologies commonly used in induction cooktops. An induction cooktop with three or more inverter switching elements connected electrically in series to control two or more inductors is known, for example, from EP 3 110 232 A1.The induction cooktop has exactly one snubber capacitor for each inverter switching element, arranged in parallel to the respective inverter switching element. This means that, disadvantageously, the capacitance of individual snubber capacitors for reducing switching losses of the inverter switching elements used to simultaneously control two inductors cannot be specifically designed for the requirements of operating a single inductor. This is particularly problematic in the case of inductors with different electromagnetic properties, such as different inductances, as switching losses cannot be optimally reduced in all operating modes, and increased switching losses occur, especially when several inductors are operated simultaneously.Furthermore, at least in some operating modes, the disadvantage arises that charging and / or discharging of individual snubber capacitors takes place directly via the inverter switching elements, which adversely causes an increase in high-frequency interference signals and thus reduces electromagnetic compatibility.

[0003] The object of the invention is, in particular but not limited to, providing a generic device with improved efficiency characteristics. 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 dependent claims.

[0004] The invention relates to an induction cooking appliance, in particular an induction hob, with an inverter unit which has at least three inverter switching elements arranged electrically in series with each other, and with a snubber unit associated with the inverter unit which has a plurality of snubber capacitors.

[0005] It is proposed that at least one of the snubber capacitors be arranged electrically in parallel with exactly two inverter switching elements of the inverter unit.

[0006] Such a design advantageously provides an induction cooking appliance with improved efficiency. In particular, switching losses occurring when switching the inverter switching elements can be advantageously reduced, preferably minimized, thereby achieving exceptionally high energy efficiency. Furthermore, when changing operating modes, for example, when switching from operation with a single independent inductor to operation with multiple independent inductors, the snubber unit can advantageously reduce the load on the inverter switching elements, thus advantageously providing a particularly low-wear and long-lasting induction cooking appliance. The design of the snubber unit also advantageously increases flexibility in the selection of the capacitances of individual snubber capacitors.This allows for the optimization of switching losses when switching the inverter switching elements, regardless of the number of simultaneously operated independent inductors. Furthermore, an advantageous arrangement of the snubber capacitors can be achieved which, in all operating modes, enables control of the inverter switching elements in such a way that direct charging and / or discharging of the snubber capacitors via one or more inverter switching elements is prevented. This advantageously reduces the occurrence of high-frequency interference signals and thus improves electromagnetic compatibility.By having at least three inverter switching elements arranged electrically in series, the inverter unit can advantageously eliminate at least one inverter switching element compared to conventional circuit arrangements with inverter switching elements in full or half-bridge configurations, while operating the same number of inductors. This also results in a space saving on the circuit board used, thus advantageously increasing cost efficiency.

[0007] The term "induction cooking appliance," and in particular "induction oven appliance," refers to at least a part, especially a subassembly, of an induction cooking appliance. An induction cooking appliance comprising the induction cooking appliance could, for example, be designed as an induction grill and / or as an induction oven and / or as a combination appliance with an additional microwave function. Preferably, an induction cooking appliance comprising the induction cooking appliance is designed as an induction cooktop. The induction cooking appliance is preferably an induction cooktop assembly. It is conceivable that the induction cooktop is designed as a matrix induction cooktop. The induction cooking appliance, and in particular the induction cooktop assembly, can also comprise the entire induction cooking appliance, and in particular the entire induction cooktop.

[0008] The induction cooking device has at least two independent inductors, each comprising at least one induction coil and designed to supply energy, in particular in the form of an alternating magnetic field, to at least one receiving element, for example, a cooking vessel, for the purpose of heating. An "independent" inductor is understood to be an inductor that can be operated independently of other independent inductors of the induction cooking device. The heating power provided by an independent inductor in an operating state can be set independently of the heating power of one or more other independent inductors of the induction cooking device. For example, several induction coils connected directly in series would not be considered a plurality of independent inductors within the meaning of the present application, since they cannot be operated independently of one another.However, several induction coils connected directly in series can together form an independent inductor, which can then be operated independently of at least one other independent inductor of the induction cooking appliance.

[0009] The inverter unit is designed to provide, in at least one operating state, an alternating current, particularly a high-frequency current, for controlling and powering at least one independent inductor. The inverter unit comprises at least three inverter switching elements arranged electrically in series with one another and may also include further inverter switching elements, which are preferably arranged electrically in series with the at least three inverter switching elements. Each inverter switching element has at least one control contact via which it can be controlled, particularly by a control unit. Advantageously, the inverter switching element is designed as a semiconductor switching element, for example as a TRIAC, preferably as a transistor, for example as a FET, a MOSFET, a JFET, or a HEMT transistor.Preferably, the inverter switching element is designed as a bipolar transistor, in particular with an insulated gate electrode (IGBT). Alternatively, the inverter switching element can be designed as a mechanical and / or electromechanical switching element, in particular as a relay. Preferably, each inverter switching element has a freewheeling diode, so that bidirectional current flow through the inverter switching element is possible.

[0010] The snubber unit is associated with the inverter unit and is designed to limit the voltage rise rate during switching of the inverter switching elements, thereby reducing, and preferably minimizing, the switching losses occurring during these switching operations. Furthermore, the snubber unit is specifically designed to protect the inverter switching elements from overvoltages. Additionally, the snubber unit is specifically designed to neutralize interfering high-frequency signals and contribute to improved electromagnetic compatibility of the induction cooker. The snubber unit comprises a plurality of snubber capacitors and may also include other elements, such as electrical resistors and / or switches. The snubber unit preferably comprises a plurality of at least four snubber capacitors.Each snubber capacitor of the snubber unit is preferably directly electrically connected to at least one terminal of one of the inverter switching elements of the inverter unit. A snubber capacitor differs from other capacitors of the induction cooking appliance, in particular from a bus capacitor and / or from a resonant capacitor, which forms an electromagnetic resonant circuit with at least one of the independent inductors, and / or from other capacitors that may be present in the induction cooking appliance, at least with regard to its arrangement and function in relation to at least one of the inverter switching elements of the inverter unit. The snubber capacitors of the snubber unit may have different electrical capacitances, at least partially.Preferably, the electrical capacitance of a snubber capacitor is specifically designed to match the electromagnetic properties, for example, the inductance and / or maximum current flow, of the respective independent inductor driven by the inverter switching element to which the snubber capacitor is directly electrically connected. The term "directly electrically connected" preferably means that one element is directly connected to another via an electrically conductive connection, without any further intervening electrical and / or electronic components.

[0011] The term "intended" should be understood to mean specifically programmed, designed, and / or equipped. The fact that an object is intended for a specific function should preferably be understood to mean that the object fulfills and / or executes this specific function in at least one application and / or operating state.

[0012] Furthermore, it is proposed that the total number of snubber capacitors in the snubber unit exceeds the total number of inverter switching elements in the inverter unit by at least one. Such a design advantageously allows for a circuit arrangement of the snubber capacitors, which reduces switching losses of the inverter switching elements through the snubber unit, using simple technical means. The total number of snubber capacitors in the snubber unit can exceed the total number of inverter switching elements in the inverter unit by exactly one. For example, in the case of an inverter unit with exactly three inverter switching elements connected electrically in series, the total number of snubber capacitors is exactly four.

[0013] Furthermore, it is proposed that at least two of the snubber capacitors be arranged electrically in parallel with exactly two inverter switching elements of the inverter unit. This advantageously allows for a further improvement in the circuit arrangement of the snubber capacitors and thus increases the efficiency of the induction cooking appliance. Moreover, flexibility is advantageously increased, since the capacitances of individual snubber capacitors can be designed completely freely and independently of the capacitances of other snubber capacitors for each operating mode, i.e., both when operating a single independent inductor and when operating several independent inductors simultaneously. This optimizes the reduction of switching losses for all operating modes of the induction cooking appliance.Preferably, a first snubber capacitor is arranged electrically in parallel to exactly one first inverter switching element and to exactly one second inverter switching element, and a second snubber capacitor is arranged electrically in parallel to exactly the second inverter switching element and to exactly one third inverter switching element.

[0014] Furthermore, it is proposed that a snubber capacitor arranged electrically in parallel with exactly two inverter switching elements be electrically connected to a collector of a first inverter switching element and to an emitter of a second inverter switching element. This configuration advantageously results in a simple circuit arrangement of the first of the at least two snubber capacitors arranged electrically in parallel with exactly two inverter switching elements. It is further proposed that a snubber capacitor arranged electrically in parallel with exactly two inverter switching elements be electrically connected to a collector of a second inverter switching element and to an emitter of a third inverter switching element.This advantageously allows for a particularly simple circuit arrangement of the second of the at least two snubber capacitors, which are arranged electrically in parallel to exactly two inverter switching elements. The second snubber capacitor is also electrically connected to the emitter of the first inverter switching element.

[0015] Furthermore, it is proposed that the induction cooking appliance has at least two BUS lines for supplying power to the inverter unit, with each snubber capacitor being directly electrically connected to at least one of the BUS lines. By directly connecting each snubber capacitor to at least one of the BUS lines, it is advantageously achieved that charging and / or discharging of the snubber capacitors in all operating modes of the induction cooking appliance always occurs directly via one of the at least two BUS lines and not via one of the inverter switching elements. This reduces the occurrence of high-frequency interference signals during charging and / or discharging of the snubber capacitors and improves the electromagnetic compatibility of the induction cooking appliance.Preferably, each snubber capacitor is directly electrically connected to exactly one of the BUS lines. In an operating state of the induction cooking device, a DC voltage supplied by a rectifier unit is present on at least one of the BUS lines to power the inverter unit. The rectifier unit can be part of the induction cooking device or part of an induction cooking appliance that incorporates the induction cooking device.

[0016] Furthermore, it is proposed that exactly two of the snubber capacitors be arranged electrically in parallel with exactly one of the inverter switching elements each. Such a configuration advantageously improves the circuit arrangement of the snubber capacitors and increases efficiency. Preferably, exactly one snubber capacitor is electrically connected in parallel with the inverter switching element that is directly electrically connected to a first of the at least two BUS lines, and exactly one snubber capacitor is electrically connected in parallel with the inverter switching element that is directly electrically connected to a second of the at least two BUS lines.

[0017] Furthermore, it is proposed that the induction cooking appliance has a plurality of independent inductors that can be operated with the inverter unit. Such a design advantageously provides a particularly efficient induction cooking appliance with a high degree of flexibility and ease of use for the user. Preferably, the inverter unit has a total number of inverter switching elements arranged in series that exceeds the total number of independent inductors by exactly one. The induction cooking appliance has a plurality of at least two independent inductors and can also have a larger number of independent inductors, for example, at least three, at least four, or at least five or more independent inductors.

[0018] Furthermore, it is proposed that the total number of snubber capacitors in the snubber unit be at least two greater than the total number of independent inductors. Such a design allows for a highly efficient induction cooking appliance. In an advantageous embodiment, the total number of snubber capacitors is exactly two greater than the total number of independent inductors. This advantageously minimizes the number of snubber capacitors required and increases cost efficiency.

[0019] Furthermore, it is proposed that the total number of snubber capacitors in the snubber unit be twice the total number of independent inductors. This can advantageously increase the energy efficiency of the induction cooking appliance. In particular, even in induction cooking appliances with a total number of independent inductors greater than two, switching losses of the inverter switching elements can be significantly reduced, preferably minimized, if the total number of snubber capacitors in the snubber unit is twice the total number of independent inductors.Furthermore, it is advantageous to enable control of the inverter switching elements in all operating modes, even in the case of induction cooking appliances with a total number of independent inductors greater than two, in which direct charging and / or discharging of the snubber capacitors via one or more inverter switching elements is prevented, thereby advantageously reducing the occurrence of high-frequency interference signals and thus achieving improved electromagnetic compatibility.

[0020] The invention further relates to an induction cooking appliance with at least one induction cooking device according to one of the previously described embodiments. Such an induction cooking appliance is characterized in particular by a high degree of efficiency, which is achieved by the previously described embodiments of the induction cooking device.

[0021] The induction cooking appliance is not intended to be limited to the application and embodiment described above. In particular, the induction cooking appliance may have a different number of individual elements, components, and units to fulfill the functionality described herein.

[0022] Further advantages become apparent from the following drawing description. The drawing illustrates four exemplary embodiments of the invention. The drawing, the description, and the claims contain numerous features in combination.

[0023] They show: Fig. 1 shows a schematic view of an induction cooking appliance with an induction cooking device, Fig. 2 shows a schematic electrical circuit diagram of the induction cooking device, Fig. 3 shows a schematic diagram illustrating the operation of the induction cooking device, Fig. 4 shows a schematic electrical circuit diagram of a further embodiment of an induction cooking device, Fig. 5 shows a schematic electrical circuit diagram of a further embodiment of an induction cooking device, and Fig. 6 shows a schematic electrical circuit diagram of a further embodiment of an induction cooking device.

[0024] Figure 1Figure 1 shows a schematic view of an induction cooking appliance 50a. The induction cooking appliance 50a is designed as an induction cooktop. The induction cooking appliance 50a has at least one induction cooking device 10a. The induction cooking device 10a is designed as an induction cooktop device. The induction cooking device 10a comprises a plurality of independent inductors. In this case, the induction cooking device 10a comprises a plurality of two independent inductors, namely an independent inductor 42a and an independent inductor 44a. The independent inductors 42a and 44a are each designed to provide energy in the form of an alternating electromagnetic field to at least one receiving element (not shown), for example, a cooking vessel (not shown) placed on a cooktop plate 52a of the induction cooking appliance 50a, which is designed as an induction cooktop, for the purpose of heating.

[0025] Figure 2Figure 1 shows a schematic electrical circuit diagram of the induction cooking appliance 10a. The induction cooking appliance 10a has an inverter unit 12a. The inverter unit 12a comprises at least three, in this case exactly three, inverter switching elements connected electrically in series: a first inverter switching element 14a, a second inverter switching element 16a, and a third inverter switching element 18a. The inverter switching elements 14a, 16a, and 18a are each designed as semiconductor switching elements, specifically insulated-gate bipolar transistors (IGBTs). The inverter switching elements 14a, 16a, and 18a are provided for controlling and powering the independent inductors 42a and 44a. The independent inductors 42a and 44a can be operated independently of each other by means of the inverter unit 12a.The first inverter switching element 14a has a first freewheeling diode 72a, the second inverter switching element 16a has a second freewheeling diode 74a and the third inverter switching element 18a has a third freewheeling diode 76a.

[0026] The induction cooking device 10a has several resonant capacitors 94a, 96a, 98a, 100a. In an operating state of the independent inductor 42a, a first resonant capacitor 94a and another first resonant capacitor 96a form a resonant circuit with the independent inductor 42a. In an operating state of the independent inductor 44a, a second resonant capacitor 98a and another second resonant capacitor 100a form a resonant circuit with the independent inductor 44a.

[0027] The induction cooking appliance 10a has a snubber unit 20a, which is assigned to the inverter unit 12a. The snubber unit 20a has a plurality of snubber capacitors, namely a first snubber capacitor 22a, a second snubber capacitor 24a, a third snubber capacitor 26a, and a fourth snubber capacitor 28a. The total number of snubber capacitors 22a, 24a, 26a, 28a exceeds the total number of inverter switching elements 14a, 16a, 18a by at least one. The total number of snubber capacitors 22a, 24a, 26a, 28a is at least two greater than the total number of independent inductors 42a, 44a. In this case, the total number of snubber capacitors 22a, 24a, 26a, 28a is twice the total number of independent inductors 42a, 44a.

[0028] At least one of the snubber capacitors 22a, 24a, 26a, 28a is electrically connected in parallel to exactly two inverter switching elements 14a, 16a, 18a. In this case, at least two, specifically exactly two, of the snubber capacitors 22a, 24a, 26a, 28a are connected in parallel to exactly two inverter switching elements 14a, 16a, 18a each. The first snubber capacitor 22a is connected in parallel to the first inverter switching element 14a and in parallel to the second inverter switching element 16a. The third snubber capacitor 26a is electrically connected to a collector 30a of the first inverter switching element 14a and to an emitter 32a of the second inverter switching element 16a. The second snubber capacitor 24a is arranged electrically in parallel to the second inverter switching element 16a and electrically in parallel to the third inverter switching element 18a.The second snubber capacitor 24a is electrically connected to a collector 34a of the second inverter switching element 16a and electrically connected to an emitter 36a of the third inverter switching element 18a.

[0029] Exactly two of the snubber capacitors 22a, 24a, 26a, 28a are electrically connected in parallel to exactly one of the inverter switching elements 14a, 16a, 18a. The third snubber capacitor 16a is electrically connected in parallel to the first inverter switching element 16a. The fourth snubber capacitor 28a is electrically connected in parallel to the third inverter switching element 18a.

[0030] The first snubber capacitor 22a and the fourth snubber capacitor 28a are provided to reduce switching losses of the inverter unit 12a when the independent inductor 42a is operating. The capacitance of the snubber unit 20a provided to reduce switching losses when the independent inductor 42a is operating alone corresponds to the sum of the capacitances of the first snubber capacitor 22a and the fourth snubber capacitor 28a. The second snubber capacitor 24a and the third snubber capacitor 26a are provided to reduce switching losses of the inverter unit 12a when the independent inductor 44a is operating. The capacitance of the snubber unit 20a provided for reducing switching losses when the independent inductor 44a is operated individually corresponds to the sum of the capacitances of the second snubber capacitor 24a and the third snubber capacitor 26a.When the independent inductor 42a and the independent inductor 44a are operated simultaneously, the capacitance of the snubber unit 20a provided to reduce switching losses corresponds to the sum of all snubber capacitors 22a, 24a, 26a, 28a.

[0031] The induction cooking appliance 10a has a rectifier unit 54a, which is designed to rectify alternating current supplied by a power supply network (not shown). The inverter unit 12a is connected to the rectifier unit 54a via two BUS lines, namely a first BUS line 46a and a second BUS line 48a. The first BUS line 46a is connected to the second BUS line 48a via a BUS capacitor 40a arranged electrically in parallel with the rectifier unit 54a.

[0032] Each of the snubber capacitors 22a, 24a, 26a, 28a is connected to at least one of the BUS lines 46a, 48a. In this case, the first snubber capacitor 22a and the fourth snubber capacitor 28a are directly connected to the first BUS line 46a, and the second snubber capacitor 24a and the third snubber capacitor 26a are each directly connected to the second BUS line 48a.

[0033] Figure 3 Figure 1 shows a schematic diagram illustrating the operation of the induction cooking device 10a. The diagram shows, by way of example, the operation of the independent inductor 42a for one period 56a. Regarding the components of the induction cooking device 10a, reference is made to the schematic electrical circuit diagram of the Figure 2Reference is made to the diagram. A current is plotted on the ordinate 102a of the diagram. A time is plotted on the abscissa 104a of the diagram. A curve 58a shows the current flowing through the independent inductor 42a. During the first section 60a of the period 56a, the first inverter switching element 14a is switched on and supplies the independent inductor 42a with a current of positive polarity. The switching-on state of the first inverter switching element 14a is indicated in the diagram by a first line 106a. During the first section 60a, the second inverter switching element 16a is switched off and the third inverter switching element 18a is switched on. During the first section 60a, the second snubber capacitor 24a is charged and the fourth snubber capacitor 28a is discharged.

[0034] During a subsequent second section 62a of period 56a, the first inverter switching element 14a is switched off and the fourth snubber capacitor 28a is charged via the first BUS line 46a. The second snubber capacitor 24a is discharged during the second section 62a, with a discharge current flowing through the independent inductor 42a.

[0035] During a third section 64a, the second inverter switching element 16a is switched on, and a current flows through the third freewheeling diode 76a of the third inverter switching element 18a and through the second freewheeling diode 74a of the second inverter switching element 16a to the independent inductor 42a. The switching-on state of the second inverter switching element 16a is indicated in the diagram by a second line 108a.

[0036] In a fourth section 66a of the period 56a, the independent inductor 42a is supplied with a current of an electrically negative polarity, which flows from the second BUS line 48a via the switched-on third inverter switching element 18a and via the switched-on second inverter switching element 16a and to the independent inductor 42a.

[0037] During a fifth section 68a of period 56a, the second inverter switching element 18a is switched off. During the fifth section 68a, the fourth snubber capacitor 28a is discharged and the second snubber capacitor 24a is charged.

[0038] In a final, sixth section 70a of period 56a, the first inverter switching element 14a is switched on, and the independent inductor 42a is supplied with current of negative polarity via the first freewheeling diode 72a. During the sixth section 70a, the fourth snubber capacitor 28a is completely discharged, and the second snubber capacitor 24a is completely charged. The third inverter switching element 18a is switched on for the entire period 56a, as indicated in the diagram by a third line 110a. After the end of the sixth section 70a, the processes described above are repeated.

[0039] In the Figures 4 to 6Three further embodiments of the invention are shown. The following descriptions are essentially limited to the differences between the embodiments, whereby with regard to identical components, features and functions, reference is made to the description of the embodiment of Figures 1 to 3 Reference can be made to. To distinguish the embodiments, the letter a in the reference numerals of the embodiment is used in the Figures 1 to 3 by the letters b to d in the reference numerals of the exemplary embodiments of the Figures 4 to 6 replaced. With regard to identically designated components, especially those with the same reference numerals, reference can generally also be made to the drawings and / or the description of the embodiment of the Figures 1 to 3 be referred.

[0040] The in the Figures 4 to 6 The illustrated embodiments differ from the embodiment of the Figures 1 to 3essentially with regard to the number of components used, with regard to the basic functionality referring to the above description of the Figures 1 to 3 can be referred.

[0041] Figure 4Figure 1 shows a further embodiment in the form of a schematic electrical circuit diagram of an induction cooking appliance 10b. In contrast to the induction cooking appliance 10a, the induction cooking appliance 10b has a higher number of independent inductors and, accordingly, a higher number of inverter switching elements and snubber capacitors. The induction cooking appliance 10b has a plurality of three independent inductors: one independent inductor 42b, one independent inductor 44b, and one independent inductor 78b. The induction cooking appliance 10b has an inverter unit 12b with a total of four inverter switching elements 14b, 16b, 18b, and 82b connected electrically in series. The induction cooking appliance 10b has a snubber unit 20b with a total of six snubber capacitors 22b, 24b, 26b, 28b, 84b, 86b.The total number of snubber capacitors 22b, 24b, 26b, 28b, 84b, 86b of the snubber unit 20b is at least two greater than the total number of independent inductors 42b, 44b, 78b. In this case, the total number of snubber capacitors 22b, 24b, 26b, 28b, 84b, 86b of the snubber unit 20b is twice the total number of independent inductors 42b, 44b, 78b. For further information regarding the operation of the induction cooking device 10b, please refer to the description of the induction cooking device 10a above.

[0042] Figure 5Figure 1 shows another embodiment of an induction cooking appliance 10c in a schematic electrical circuit diagram. In contrast to the induction cooking appliance 10b, the induction cooking appliance 10c has an even greater number of independent inductors and, consequently, an even greater number of inverter switching elements and snubber capacitors. The induction cooking appliance 10b has a plurality of four independent inductors: one independent inductor 42c, one independent inductor 44c, one independent inductor 78c, and one independent inductor 80c. The induction cooking appliance 10c has an inverter unit 12c with a total of five inverter switching elements 14c, 16c, 18c, 82c, and 88c connected electrically in series.The induction cooking device 10c has a snubber unit 20c with a total of eight snubber capacitors 22c, 24c, 26c, 28c, 84c, 86c, 90c, 92c. The total number of snubber capacitors 22c, 24c, 26c, 28c, 84c, 86c, 90c, 92c of the snubber unit 20c is at least two greater than the total number of independent inductors 42c, 44c, 78c, 80c. In this case, the total number of snubber capacitors 22c, 24c, 26c, 28c, 84c, 86c, 90c, 92c of the snubber unit 20c corresponds to twice the total number of independent inductors 42c, 44c, 78c, 80c. Regarding the operation of the induction cooking device 10c, reference can otherwise be made to the above description of the induction cooking device 10a.

[0043] Figure 6Figure 1 shows a further embodiment of an induction cooking appliance 10d in a schematic electrical circuit diagram. The induction cooking appliance 10d has a plurality of three independent inductors: one independent inductor 42d, one independent inductor 44d, and one independent inductor 78d. The induction cooking appliance 10d has an inverter unit 12d with a total of four inverter switching elements 14d, 16d, 18d, and 82d connected electrically in series. This differs from the embodiment of the induction cooking appliance 10b according to Figure 1. Figure 4The induction cooking appliance 10d has a snubber unit 20d with a smaller total number of five snubber capacitors 22d, 24d, 26d, 28d, 84d. The induction cooking appliance 10d has at least two BUS lines 46d, 48d for supplying power to the inverter unit 12d. In contrast to the previous embodiments, not all snubber capacitors 22d, 24d, 26d, 28d, 84d are directly electrically connected to one of the BUS lines 46d, 48d. The fifth snubber capacitor 84d, unlike the one in the Figure 4 In the illustrated embodiment, the fifth snubber capacitor 84d is not directly connected to one of the BUS lines 46d, 48d, so that in some operating states of the induction cooking appliance 10d, charging and / or discharging of the fifth snubber capacitor 84d takes place via the first inverter switching element 14d or via the fourth inverter switching element 82d. Reference sign

[0044] 10 Induction cooker device 12 Inverter unit 14 First inverter switching element 16 Second inverter switching element 18 Third inverter switching element 20 Snubber unit 22 First snubber capacitor 24 Second snubber capacitor 26 Third snubber capacitor 28 Fourth snubber capacitor 30 Collector 32 Emitter 34 Collector 36 Emitter 40 BUS capacitor 42 Independent inductor 44 Independent inductor 46 First BUS line 48 Second BUS line 50 Induction cooker 52 Cooktop 54 Rectifier unit 56 Period 58 Curve 60 First section 62 Second section 64 Third section 66 Fourth section 68 Fifth section 70 sixth section 72 first freewheeling diode 74 second freewheeling diode 76 third freewheeling diode 78 independent inductor 80 independent inductor 82 fourth inverter switching element 84 fifth snubber capacitor 86 sixth snubber capacitor 88 fifth inverter switching element 90 seventh snubber capacitor 92 eighth snubber capacitor 94 firstResonance capacitor 96 further first resonance capacitor 98 second resonance capacitor 100 further second resonance capacitor 102 ordinate 104 abscissa 106 first line 108 second line 110 third line

Claims

1. Induction cooking appliance apparatus (10a-d), in particular induction hob apparatus, with an inverter unit (12a-d), which has at least three inverter switching elements (14a-d, 16a-d, 18a-d, 82b-d, 88c) arranged electrically in series relative to one another, and with a snubber unit (20a-d) assigned to the inverter unit (12a-d), which has a number of snubber capacitors (22a-d, 24a-d, 26a-d, 28a-d, 84b-d, 86b-c, 90c, 92c), characterised in that at least one of the snubber capacitors (22a-d, 24a-d, 26a-d, 28a-d, 84b-d, 86b-c, 90c, 92c) is arranged electrically parallel to exactly two inverter switching elements (14a-d, 16a-d, 18a-d, 82b-d, 88c) of the inverter unit (12a-d).

2. Induction cooking appliance apparatus (10a-d) according to claim 1, characterised in that a total number of snubber capacitors (22a-d, 24a-d, 26a-d, 28a-d, 84b-d, 86b-c, 90c, 92c) of the snubber unit (20a-d) exceeds a total number of inverter switching elements (14a-d, 16a-d, 18a-d, 82b-d, 88c) of the inverter unit (12a-d) by at least one.

3. Induction cooking appliance apparatus (10a-d) according to claim 1 or 2, characterised in that at least two of the snubber capacitors (22a-d, 24a-d, 26a-d, 28a-d, 84b-d, 86b-c, 90c, 92c) are arranged electrically parallel to exactly two inverter switching elements (14a-d, 16a-d, 18a-d, 82b-d, 88c) of the inverter unit (12a-d) in each case.

4. Induction cooking appliance apparatus (10a-d) according to claim 3, characterised in that a snubber capacitor (26a; 22b; 90c; 22d) arranged electrically parallel to exactly two inverter switching elements (14a-d, 16a-d) is connected in an electrically conductive manner to a collector (30a-d) of a first inverter switching element (14a-d) and to an emitter (32a-d) of a second inverter switching element (16a-d).

5. Induction cooking appliance apparatus (10a; 10d) according to claim 3 or 4, characterised in that a snubber capacitor (24a, 84d) arranged electrically parallel to exactly two inverter switching elements (16a 18a; 16d; 18d) is connected in an electrically conductive manner to a collector (34a; 34d) of a second inverter switching element (16a; 16d) and to an emitter (36a; 36d) of a third inverter switching element (18a; 18d).

6. Induction cooking appliance apparatus (10a-c) according to one of the preceding claims, characterised by at least two bus lines (46a-c, 48a-c) for supplying power to the inverter unit (12a-c), wherein each snubber capacitor (22a-c, 24a-c, 26a-c, 28a-c, 84b-c, 86b-c, 90c, 92c) is directly connected in an electrically conductive manner to at least one of the bus lines (46a-c, 48a-c).

7. Induction cooking appliance apparatus (10a-d) according to one of the preceding claims, characterised in that exactly two of the snubber capacitors (22a, 28a; 28b, 86b; 26c, 28c; 26d, 28d) are arranged electrically parallel to exactly one of the inverter switching elements (14a, 18a; 14b, 82b;14c, 88c; 14d, 82d) in each case.

8. Induction cooking appliance apparatus (10a-d) according to one of the preceding claims, characterised by a number of independent inductors (42a-d, 44a-d, 78b-d, 80c) which can be operated with the inverter unit (12a-d).

9. Induction cooking appliance apparatus (10a-d) according to claim 8, characterised in that the total number of snubber capacitors (22a-d, 24a-d, 26a-d, 28a-d, 84b-d, 86b-c, 90c, 92c) of the snubber unit (20a-d) is greater than a total number of the independent inductors (42a-d, 44a-d, 78b-d, 80c) by at least two.

10. Induction cooking appliance apparatus (10a-c) according to claim 8 or 9, characterised in that the total number of snubber capacitors (22a-c, 24a-c, 26a-c, 28a-c, 84b-c, 86b-c, 90c, 92c) of the snubber unit (20a-c) is twice as great as the total number of independent inductors (42a-c, 44a-c, 78b-c, 80c).

11. Induction cooking appliance (50a) with a least one induction cooking apparatus (10a-d) according to one of the preceding claims.

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