COOKING DEVICE

Description

[0001] The invention relates to a cooking appliance device according to claim 1 and a method for operating a cooking appliance device according to claim 14.

[0002] EP 2 548 407 B1 already discloses a hob with a half-bridge or full-bridge circuit for operating several inductors by means of a multiplexer.

[0003] From WO 2018 / 116053 A1 and WO 2018 / 116055 A1, a hob is already known which has a number N×M of heating matrix elements, wherein an i, j-th heating matrix element comprises at least one inductor and is connected to both an i-th row switching element and a j-th column switching element.

[0004] The object of the invention is, in particular, to provide a generic device with improved properties with regard to efficiency, in particular energy efficiency and / or component efficiency. This object is achieved according to the invention by the features of claims 1 and 12, while advantageous embodiments and further developments of the invention can be found in the subclaims.

[0005] A cooking appliance device, in particular a hob device, is proposed with a plurality of at least two heating branches, each comprising at least one heating unit, preferably an induction heating unit, and at least one branch switching unit, with a switching unit common to the heating branches and with at least one control unit which, in an operating state for setting a heating power of at least one of the heating branches to be operated, adapts at least one switching parameter of a switching parameter set of the branch switching unit of the at least one heating branch to be operated.

[0006] Such a design makes it possible to achieve high efficiency, in particular high energy efficiency. By reducing the number of components, increased component efficiency and / or cost efficiency can be achieved. In particular, independent power adjustment can be made for all heating branches, which in particular makes it possible to achieve high flexibility. When heating cooking utensils, improved homogeneity can be achieved. In particular, uneven heating of cooking utensils can be avoided. Unwanted overheating, in particular of a cooking utensil edge, can be avoided. A heating output can be adjusted, in particular proportional to the coverage of the heating branch by the cooking utensil. In particular, a power adjustment can be made independently of different cooking utensils.Energy can be supplied continuously and in particular without pulses, which in particular makes it possible to avoid acoustic noise. In particular, an excessive power supply to achieve an average power output can be dispensed with. Overpower and / or a boost mode can be dispensed with, which in particular makes it possible to increase efficiency. Energy can be supplied constantly. Furthermore, unwanted alternative heating can be avoided. Likewise, electromagnetic compatibility of the cooking appliance can be improved by such a configuration, which can prevent flicker. The cooking appliance can in particular be operated with a reduced switching frequency, which in particular makes it possible to achieve improved efficiency.

[0007] A "cooking appliance device," in particular a "cooktop device," should be understood to mean at least one part, in particular a subassembly, of a cooking appliance, in particular a cooktop. The cooking appliance could, for example, be designed as an oven, in particular an induction oven, and / or as a combination appliance with an additional microwave function. The cooking appliance is preferably designed as a cooktop, in particular as an induction cooktop, preferably as a matrix cooktop, and particularly preferably as a matrix induction cooktop. In particular, the cooking appliance device, in particular the cooktop device, can also comprise the entire cooking appliance, in particular the entire cooktop.

[0008] The cooking appliance advantageously has at least four, preferably at least 10, and particularly preferably at least 20 heating branches. A "heating branch" is to be understood in particular as an electronic and / or electrical unit, which in particular comprises a plurality of electronic and / or electrical components, in particular at least one, and advantageously exactly one, heating unit and at least one, and advantageously exactly one, branch switching unit. The heating branches of the cooking appliance could, for example, be constructed identically to one another. Alternatively, the heating branches of the cooking appliance could differ at least with regard to the heating units, in particular with regard to diameters and / or types of heating units. Alternatively or additionally, the heating branches of the cooking appliance could, for example, differ with regard to the number of heating units.

[0009] A "heating unit" is understood in particular to mean a unit which, in an operating state, provides a heating power for heating a cooking utensil and / or a cooking muffle wall, wherein in particular a heating power of at least 100 W, preferably of at least 250 W, and particularly preferably of at least 500 W can be set. An "induction heating unit" is understood in particular to mean a heating unit with at least one induction heating element, in particular an inductor, which can be supplied with high-frequency current, in particular with a frequency of at least 10 kHz, preferably of at least 20 kHz, and in particular of a maximum of 100 kHz, to generate an alternating magnetic field. The induction heating unit can comprise several induction heating elements connected in series and / or in parallel, for example to provide a multi-circuit or roasting cooking zone.

[0010] A "branch switching unit" is to be understood in particular as a unit of a heating branch, which in particular comprises at least one switching unit. A "switching unit" is to be understood in particular as a unit with at least one switching element, which is intended in particular to establish and / or break an electrically conductive connection between two contacts of the switching element. The switching element preferably has at least one control contact via which it can be controlled. In particular, the switching element is designed as a semiconductor switching element, in particular as a transistor, advantageously as a bipolar transistor with a preferably insulated gate electrode (IGBT). Alternatively, the switching element can be designed as a mechanical and / or electromechanical switching element, in particular as a relay.For example, the switching element can be designed as a FET, a MOSFET, preferably as an RC-IGBT, and particularly preferably as a HEMT transistor. The switching unit can comprise a plurality of switching elements, which can be connected to one another, for example, in series and / or parallel.

[0011] To adjust the heating output of at least one of the heating branches to be operated, i.e., to adjust the heating output of the corresponding heating unit of the heating branch, the control unit advantageously adjusts, in an operating state, at least two switching parameters of a switching parameter set of the branch switching unit of the at least one heating branch to be operated. In particular, the switching parameter is different from a switching frequency of the branch switching unit.In particular, the control unit is designed to control the branch switching units and the common switching unit in pairs as inverter switching elements, in particular such that a soft switching operation occurs between at least a first switching state, in which two contacts of the common switching unit are electrically connected while two contacts of all branch switching units are disconnected, and a second switching state, in which two contacts of at least one of the branch switching units are electrically connected while the two contacts of the common switching unit are disconnected. A "soft switching operation" is to be understood, in particular, as a switching operation with negligibly low power loss, which occurs particularly when the switching operation is preferably at least substantially voltage-free.An "at least substantially voltage-free switching operation," also known as "zero voltage switching (ZVS)," is understood in particular to mean a soft switching operation in which a voltage, particularly applied to and / or dropped across the branch switching unit, is at least substantially negligible, in particular substantially zero. A "negligible value" is understood in particular to mean a value that is, in particular, at least by a factor of 10, advantageously by a factor of 50, preferably by a factor of 100, and particularly preferably by a factor of 500 lower than a maximum operating value.

[0012] A "control unit" is understood in particular to be an electronic unit that is preferably at least partially integrated into a control and / or regulating unit of a cooking appliance. The control unit preferably comprises a computing unit and, in particular, in addition to the computing unit, a memory unit with a control and / or regulating program stored therein, which is intended to be executed by the computing unit. A "switching parameter set" is understood in particular to be a set of at least one switching parameter and preferably several switching parameters. In particular, a switching parameter set is at least one switching parameter associated with a heating branch. A "switching parameter" is understood in particular to be a parameter that, during operation of the switching unit, is directly within the sphere of influence of the control unit and / or can be controlled and / or regulated by it.Alternatively or additionally, the switching parameter may be within the sphere of influence of a user and thus be controlled and / or selected indirectly or directly by a user.

[0013] "Intended" should be understood, in particular, to mean specifically programmed, designed, and / or equipped. The fact that an object is intended for a specific function should be understood, in particular, to mean that the object fulfills and / or performs this specific function in at least one application and / or operating state. An "operating state" should be understood, in particular, to mean a state of the cooking appliance in which at least one of the heating branches is operating.

[0014] It is further proposed that the control unit periodically operates the branch switching units of the heating branches to be operated, each with a common period duration. This makes it possible, in particular, to provide a particularly efficient cooking appliance. The period of one of the branch switching units with the common period duration can, for example, start at a different time than the period of another of the branch switching units with the common period duration. However, the periods preferably start simultaneously. A "period duration" is to be understood, in particular, as the inverse of a frequency at which one of the branch switching units and / or the common switching unit switches. The fact that the control unit "each operates the branch switching units of the heating branches to be operated with a common period duration" is to be understood, in particular, as meaning that the period durations at which the branch switching units are operated are equal.

[0015] For example, in the operating state, the control unit could periodically operate the common switching unit with a different period than the branch switching units, in particular with any desired period. If the control unit periodically operates the common switching unit with the common period in the operating state, a particularly efficient cooking appliance can be provided. Since the heating output of a heating branch to be operated can be adjusted in particular via parameters which can be independent of a switching frequency and thus in particular independent of the common period, the common period can be selected to be constant and as efficient as possible. The cooking appliance is particularly efficient if the common period corresponds at least substantially to a reciprocal of a resonant frequency of an oscillating circuit with conventional cooking utensils set up.If the switching frequency, i.e. the reciprocal of the common period, at least substantially corresponds to the resonant frequency, switching losses are minimal. The switching frequency is particularly preferably in the range from 20 kHz to 35 kHz, which corresponds to a common period of 0.05 ms to 0.029 ms. During a first period of the common period, in particular the common switching unit is switched to pass and all branch switching units are switched to break. In particular, a duration of the first period corresponds at least substantially to half of the common period. The duration of the first period should preferably be selected such that the rated power is higher than or equal to the desired heating power of one of the heating branches to be operated. During a second period of the common period, in particular the common switching unit is switched to break.In an operating state, depending on the switching parameter set of the branch switching unit of the heating branches to be operated, the branch switching unit of at least one heating branch to be operated is at least partially switched to conduction within the second period of the common period duration. The duration of the second period duration corresponds in particular to the common period duration minus the duration of the first period duration.

[0016] If the switching parameter set comprises at least one switch-on time of the branch switching unit of the at least one heating branch to be operated, a particularly flexible control of the heating output of the cooking appliance, in particular of the at least one heating branch to be operated, can be achieved. In particular, a period-related time interval between a conduction time period of the common switching unit and a conduction time period of a branch switching unit can be specifically changed. By specifically changing the switch-on time of the branch switching unit of the at least one heating branch to be operated, a heating output of the heating branch to be operated can be influenced. Preferably, a heating output can be reduced by increasing the period-related time interval between a conduction time period of the common switching unit and a conduction time period of a branch switching unit.

[0017] A "conducting period" of the branch switching unit and / or the common switching unit is to be understood in particular as a period of time during which a first and a second main contact of the branch switching unit and / or the common switching unit are electrically connected. A "main contact" of the branch switching unit and / or the common switching unit is to be understood in particular as a contact of the branch switching unit and / or the common switching unit that is provided for conducting a current to a consumer unit that is formed separately from the branch switching unit and / or the common switching unit.A "time interval between a first transmission period and a second transmission period" is to be understood in particular as a duration of a time interval that begins with the end of the transmission period that expires earlier and ends with the beginning of the transmission period that begins later. A "period-related time interval" is to be understood in particular as a duration of a time interval divided by the period duration.

[0018] Furthermore, it is proposed that the switching parameter set comprise at least one duty cycle of the branch switching unit of the at least one heating branch to be operated. This allows for particularly flexible control of the heating output of the cooking appliance, in particular of the at least one heating branch to be operated. In particular, the "duty cycle of the branch switching unit of the at least one heating branch to be operated" is to be understood as a period-related conduction time period of the branch switching unit. Advantageously, this is to be understood as a period within the second period portion of the common period duration during which the branch switching unit is switched conduction. In particular, the heating output of the heating branch can be changed by changing the duty cycle of the branch switching unit of the at least one heating branch to be operated.Preferably, a heating power can be reduced by reducing the duty cycle of the branch switching unit of the at least one heating branch to be operated.

[0019] In particular, the control and / or regulation of the heating output of a heating branch can be achieved by changing, in particular, several switching parameters. For example, the heating output of a heating branch can be achieved by a combined change in the switch-on time of the branch switching unit of the at least one heating branch to be operated and the switch-on duration of the branch switching unit of the at least one heating branch to be operated. Alternatively or additionally, a change in a single switching parameter could regulate the heating output of a heating branch.

[0020] For example, the control unit could operate and / or control all branch switching units with a single common switching parameter set. However, it is proposed that the control unit operates and / or controls each of the branch switching units with its own switching parameter set. This allows particularly flexible adjustment of the heating output. In particular, this can achieve high efficiency. In particular, the switching parameters of one switching parameter set can assume different values than the switching parameters of another switching parameter set. It is also conceivable that the switching parameters of one switching parameter set assume the same values than the switching parameters of another switching parameter set. In particular, all switching parameter sets contain the same switching parameters. It is also conceivable that the switching parameter sets differ from one another in the scope of switching parameters.

[0021] It is further proposed that the heating branches each have at least one branch diode that blocks the heating branches from one another. This enables, in particular, independent power adjustment for the heating branches. For example, a current flow, in particular a potential flow, between the heating branches could not be prevented in any direction. The fact that the branch diode "blocks" the heating branches from one another should be understood in particular to mean that the two diode prevents a current flow from one heating branch to another. This means, in particular, that the branch diode prevents a backflow and thus, in particular, a discharge of an electrical potential from one heating branch via another heating branch.

[0022] If the branch diodes are arranged in front of the corresponding branch switching units, viewed from the common switching unit, the heating branches can be blocked particularly effectively from one another.

[0023] It is further proposed that the heating branches each have at least one resonance unit, which, together with the associated heating units, in particular induction heating units, forms part of a resonant circuit. In particular, cooking utensils and / or a cooking muffle wall, for example, can also be part of the resonant circuit. A "resonance unit" is to be understood in particular as a unit that comprises at least one resonance capacitance, preferably formed by at least one capacitor, which is preferably different from a damping capacitance and / or a capacitance connected in parallel to a switching element. In particular, a resonance capacitance is formed by a combination of series and parallel connections of several capacitors. The resonance capacitance is in particular a component of an electrical resonant circuit, in particular an electrical series resonant circuit.Preferably, the resonance capacitance is connected in series with the heating unit in at least one operating state, in particular via one of the branch switching units and / or the common switching unit, and is particularly advantageously provided to be charged via the heating unit, in particular when the heating unit is placed at a higher electrical potential by the branch switching unit and / or the common switching unit. The resonance capacitance is arranged in particular on a side of the heating unit facing away from the common switching unit, viewed in the direction of a conduction path. For example, the resonance unit could be dimensioned such that the resonance frequency of the resonant circuit with conventional cooking utensils is less than 25 kHz or more than 35 kHz.Preferably, the resonance frequency of the resonant circuit with conventional cooking utensils is 25 kHz to 35 kHz, which in particular avoids acoustic noise and / or large power losses, in particular switching losses.

[0024] The common switching unit could have exactly one switching element. However, the common switching unit advantageously has at least two switching elements connected in parallel. In particular, the control unit can be configured to switch the two parallel-connected switching elements simultaneously or alternately, in particular to thereby distribute thermal load across the two switching elements.

[0025] For example, the cooking appliance could have a cooling unit that cools the common switching unit and the individual branch switching units equally. Alternatively, the cooling unit could cool the individual branch switching units more than the common switching unit. If the cooking appliance has a cooling unit that cools the common switching unit more than the individual branch switching units, the load on the common switching unit can be reduced. In particular, this can extend the service life of the cooking appliance, which can, in particular, increase user-friendliness. A "cooling unit" should be understood to mean a unit that is specifically designed to cool additional components, in particular an electronic unit, and is in thermal and preferably direct mechanical contact with these components.To release heat energy to the environment, the cooling unit has, in particular, a surface area that is at least 5 times, in particular at least 10 times, advantageously at least 20 times, and particularly advantageously at least 50 times larger than a cube of the same volume and comprises, in particular, at least 3, in particular at least 10, and advantageously at least 20 cooling fins. Alternatively or additionally, the cooling unit could, for example, comprise a Peltier element.

[0026] It is further proposed that the cooking appliance device has a plurality of at least two further heating branches, each comprising at least one further heating unit and at least one further branch switching unit, with a further switching unit common to the further heating branches, wherein the control unit, in an operating state for setting a heating output of at least one of the further heating branches to be operated, adapts at least one further switching parameter of a further switching parameter set of the further branch switching unit of the at least one further heating branch to be operated. Such a configuration makes it possible to provide a cooking appliance device with particularly high flexibility. In particular, the heating branches to be operated are independent of the further heating branches to be operated. This makes it possible, for example, to provide a matrix hob with several mutually independent matrix areas.In particular, the independent matrix areas can have different nominal power ratings, which significantly increases flexibility. In particular, this allows a wider range of possible heating outputs to be achieved.

[0027] Furthermore, a hob, in particular a matrix hob, with at least one cooking appliance device is proposed.

[0028] Efficiency, in particular energy efficiency and / or component efficiency, can be further increased in particular by a method for operating a cooking appliance device with a plurality of at least two heating branches, each comprising at least one heating unit and at least one branch switching unit, and with a switching unit common to the heating branches, in which method at least one switching parameter of a switching parameter set of the branch switching unit of the at least one heating branch to be operated is adapted in order to set a heating output of at least one of the heating branches to be operated.

[0029] The cooking appliance device is not intended to be limited to the application and embodiment described above. In particular, the cooking appliance device may have a number of individual elements, components, and units that differs from the number stated herein to fulfill a functionality described herein.

[0030] 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 further meaningful combinations.

[0031] They show: Fig. 1A cooking appliance designed as a hob with a cooking appliance device in a schematic plan view, Fig. 2A schematic circuit diagram of a part of the cooking appliance device with three heating branches, Fig. 3Switching and voltage states of a common switching unit of the cooking appliance device and of two branch switching units of the cooking appliance device based on an exemplary switching parameter set, Fig. 4A diagram with an exemplary power curve of one of the heating branches as a function of a switch-on time of a branch switching unit of the heating branch, Fig. 5A diagram with an exemplary power curve of one of the heating branches as a function of a switch-on time of a branch switching unit of the heating branch, Fig. 6A diagram with an exemplary power curve of one of the heating branches as a function of a switch-on time with a constant switch-on time of a branch switching unit of the heating branch,7 diagrams with exemplary current and voltage curves for a reference heating power and for two heating powers adjusted by means of a switching parameter set, Fig. 8 diagrams with exemplary current and voltage curves for the reference heating power and for two further heating powers adjusted by means of a switching parameter set, Fig. 9 diagrams with exemplary current and voltage curves for the reference heating power and for a heating power adjusted by means of a switching parameter set, Fig. 10 a schematic circuit diagram of part of a further embodiment of a cooking appliance, Fig. 11 a cooking appliance designed as a matrix hob with an alternative embodiment of a cooking appliance in a schematic plan view and Fig. 12 a schematic circuit diagram of part of the cooking appliance from . Fig. 11 .

[0032] Of the multiple objects present, only one is provided with a reference symbol in the figures.

[0033] Figure 1 shows a cooking appliance designed as a hob 32a, which in the example shown is designed as an induction hob. The hob 32a has a cooking appliance device 10a designed as a hob device, parts of which in Figure 2 are shown in more detail.

[0034] The cooking appliance 10a has a plurality of heating branches 12a. In the illustrated example, the cooking appliance 10a has four heating branches 12a, one for each heating zone 70a of the cooking appliance 10a. Alternatively, the cooking appliance 10a could also have a different number of heating branches 12a and / or heating zones 70a.

[0035] The cooking appliance 10a has a common switching unit 18a for the heating branches 12a. In the example shown, the common switching unit 18a has a switching element 38a. The switching element 38a is designed as a bipolar transistor. A collector of the common switching unit 18a is connected to a bus potential 62a. The bus potential 62a is one of the rectified busbars of a rectifier of the cooking appliance 10a (not shown). An emitter of the common switching unit 18a is connected to the plurality of heating branches 12a.

[0036] Each of the heating branches 12a has a heating unit 14a and a branch switching unit 16a. The heating unit 14a is designed as an induction heating unit. A first connection of the heating unit 14a is connected to a resonance unit 36a of the respective heating branch 12a. The resonance unit 36a forms part of an oscillating circuit with the associated heating unit 14a. The resonance unit 36a has two capacitors 52a. One connection of each capacitor 52a is connected to the heating unit 14a. Another connection of the capacitor 52a is connected to the bus potential 62a or a ground potential 64a. The ground potential 64a is the potential of another rectified busbar of the rectifier of the cooking appliance 10a (not shown).

[0037] A second terminal of the heating unit 14a is connected to the branch switching unit 16a. The branch switching unit 16a comprises a bipolar transistor and a parallel-connected branch switching diode 54a. An emitter of the transistor of the branch switching unit 16a is connected to the parallel-connected branch switching diode 54a and to the heating unit 14a. A collector of the transistor of the branch switching unit 16a is connected to the parallel-connected branch switching diode 54a and to ground potential 64a.

[0038] A diode 56a of each heating branch 12a, connected in parallel with the common switching unit 18a, is connected at its anode to the second terminal of the heating unit 14a. The parallel-connected diode 56a is connected at its cathode to the bus potential 62a.

[0039] A branch diode 30a of heating branch 12a is also connected to the second terminal of heating unit 14a. The branch diode 30a is arranged upstream of the associated branch switching units 16a, as viewed from the common switching unit 18a. The branch diode 30a is connected by its cathode to the second terminal of heating unit 14a. The branch diode 30a is connected by its anode to the common switching unit 18a. The branch diode 30a blocks the heating branches 12a from each other and prevents an unwanted potential flow from one of the heating branches 12a to another heating branch 12a.

[0040] The branch switching units 16a and the common switching unit 18a are cooled, which in Figure 2schematically represented by the respective waste heat 58a. The cooking appliance 10a has a cooling unit 40a for cooling the common switching unit 18a and the branch switching units 16a, which cooling unit cools the common switching unit 18a more than the individual branch switching units 16a (schematically represented by waste heat 58a). The cooling unit 40a has, for example, a heat sink for each of the common switching unit 18a and the branch switching units 16a (not shown). Alternatively or additionally, the cooling unit 40a could comprise a fan, which, for example, ensures convection on all heat sinks and / or on all branch switching units 16a and the common switching unit 18a.

[0041] Furthermore, the cooking appliance device 10a has a control unit 20a, which in Figure 2 is also shown schematically.

[0042] The control unit 20a operates the branch switching units 16a of the heating branches 12a to be operated in an operating state periodically with a common period duration 28a. In this operating state, the control unit 20a also operates the common switching unit 18a periodically with the common period duration 28a.

[0043] Figure 3 shows exemplary switching states within the common period 28a using an exemplary switching parameter set using the example of the common switching unit 18a and two branch switching units 16a. The curve V SH shows the time periods in which the common switching unit 18a periodically passes the bus potential 62a common to all heating branches 12a with the common period 28a.

[0044] To set a heating output 60a of the heating branches 12a to be operated in an operating state, the control unit 20a adjusts two switching parameters 22a of a switching parameter set of the branch switching unit 16a of a heating branch 12a to be operated. The heating output 60a of a heating branch 12a to be operated corresponds to the heating output 60a of the heating unit 14a of the heating branch 12a to be operated. The control unit 20a operates all branch switching units 16a with their own switching parameter set. In the example shown, the common period duration 28a for the displayed switching states of the two branch switching units 16a begins simultaneously.

[0045] The switching parameter set includes a switch-on time 24a of the branch switching unit 16a of the heating branch 12a to be operated. Furthermore, the switching parameter set includes a switch-on duration 26a of the branch switching unit 16a of the heating branch 12a to be operated. The heating output 60a is adjusted by changing the switch-on time 24a and the switch-on duration 26a.

[0046] Curves V SL1 and V SL2 show the respective duty cycles 26a of the branch switching units 16a of heating branches 12a to be operated, in which the branch switching unit 16a periodically passes the ground potential 64a with the common period duration 28a. The duty cycle 26a begins periodically with the switch-on time 24a.

[0047] The common period duration 28a lies in the range from 0.01 ms to 0.05 ms. The duty cycle 26a of the respective branch switching units 16a of heating branches 12a to be operated lies in the range from 0.005 ms to 0.025 ms. The duty cycle 26a of the branch switching unit 16a can correspond to a maximum of the common period duration 28a, less the conduction time of the common switching unit 18a. A shorter duty cycle 26a of the branch switching unit 16a reduces the heating power 60a. The relationship between the duty cycle 26a of the branch switching unit 16a, the switch-on time 24a of the branch switching unit 16a, and the heating power 60a of the heating branch 12a is shown in the Figures 4 to 6 shown in more detail.

[0048] A later switch-on time 24a of the branch switching unit 16a corresponds to a larger period-related time interval between a conduction time period of the common switching unit 18a and a conduction time period of the branch switching unit 16a.

[0049] The larger period-related time interval between the conduction time period of the common switching unit 18a and the conduction time period of the branch switching unit 16a results in a reduced heating power 60a of the heating branch 12a as soon as the period-related time interval is greater than a switching time of the common switching unit 18a and / or the respective branch switching unit 16a.

[0050] Figure 4 shows an example of the relationship between the heating power 60a in watts, which is on an ordinate of the Figure 4 is shown, depending on the switch-on time 24a, which is on an abscissa of the Figure 4 Depending on the desired heating power 60a, the control unit 20a can select the switch-on time 24a in a range of half a common period 28 less the switch-on time 26a. Figure 4The possible range of the switch-on time 24a of half a common period 28a is shown as a phase angle from 0° to 180° on the abscissa. The heating power 60a can be reduced by changing the switch-on time 24a, starting from a maximum heating power 60a at small phase angles, down to a value of 0 W at phase angles close to 180°.

[0051] Figure 5 shows an example of the relationship between the heating power 60a in watts, which is on an ordinate of the Figure 5 is shown, depending on the duty cycle 26a, which is on an abscissa of the Figure 5 Depending on the desired heating power 60a, the control unit 20a can adjust the duty cycle 26a in a range of up to half a common period 28, which corresponds to a maximum possible period-related conduction time of the branch switching unit 16a. In Figure 5the possible range of the duty cycle 26a of half a common period 28a is shown as a phase angle from 0° to 180° on the abscissa.

[0052] The relationship therefore applies that the duty cycle 26a is equal to or less than half the common period 28a minus the period-related time interval between a conduction period of the common switching unit 18a and a conduction period of the branch switching unit 16a. For an exemplary constant duty cycle 26a, Figure 6the heating power 60a of a heating branch 12a resulting from the switch-on time 24a. With a constant switch-on time 26a and a change in the switch-on time 24a within a certain range, an at least substantially constant heating power 60 can be achieved. This allows, in particular, a high degree of flexibility to be achieved, especially when a plurality of heating branches 12a are to be operated. In particular, this allows improved efficiency to be achieved, particularly with regard to the controllability of the voltages and switching losses.

[0053] Figures 7a and 8ashow, by way of example, a voltage and current curve for a reduced heating power 68a on a heating branch 12a of, for example, 1400 W and for a reference heating power 66a on another heating branch 12a of 1800 W. In addition, the potentials switched for this purpose within the common period 28a by the common switching unit 18a and the respective branch switching unit 16a are shown.

[0054] Figures 7b and 8b show the exemplary voltage and current curve for the reduced heating power 68a on a heating branch 12a of 1000 W as well as for the reference heating power 66a on another heating branch 12a of 1800 W.

[0055] Figures 9a and 9b show two different exemplary voltage and current curves for the reduced heating power 68a on two heating branches 12a of 1400 W as an example and for the reference heating power 66a on another heating branch 12a of 1800 W.

[0056] The Figures 7a and 7b , 8a and 8b as well as 9a and 9b The voltage and current curves shown for the respective heating power 60a are each based on the same common period duration 28a.

[0057] In the Figures 10 to 12 Two further embodiments of the invention are shown. The following descriptions are essentially limited to the differences between the embodiments, whereby with regard to the same components, features and functions, reference is made to the description of the other embodiments, in particular the Figures 1 to 9 , can be referred to. To distinguish the embodiments, the letter a in the reference numerals of the embodiment of the Figures 1 to 9 by the letters b and c in the reference numerals of the embodiments of the Figures 10 to 12With regard to components with the same designation, in particular with regard to components with the same reference numerals, reference can in principle also be made to the drawings and / or the description of the other embodiments, in particular the Figures 1 to 9 , be referred to.

[0058] Figure 10 shows part of a cooking appliance 10b. A common switching unit 18b here has two switching elements 38b connected in parallel. A control unit 20b is provided to switch the switching elements 38b simultaneously in order to reduce the thermal load on the switching elements 38b and increase their service life. Alternatively, it would be conceivable for the control unit 20b to be provided to switch the switching elements 38b alternately, which can also reduce the respective thermal load.

[0059] The Figures 11 and 12show a cooking appliance configured as a hob 32c with a cooking appliance device 10c. The hob 32c is designed as a matrix hob. The cooking appliance device 10c has a first group 72c of heating units 14c and a second group 74c of additional heating units 44c. In the example shown, each of the groups 72c and 74c has 24 heating units 14c and additional heating units 44c.

[0060] Analogous to the previous embodiments, the cooking appliance 10c has a plurality of heating branches 12c. The heating units 14c of the first group 72c are part of the heating branches 12c. The cooking appliance 10c has a plurality of further heating branches 42c. The further heating branches 42c each have one of the further heating units 44c, which are part of the second group 74c.

[0061] Furthermore, the further heating branches 42c each comprise a further branch switching unit 46c. The cooking appliance device 10c comprises a further switching unit 48c common to the further heating branches 42c.

[0062] In an operating state for setting a heating power 60c of at least one of the further heating branches 42c to be operated, a control unit 20c adapts at least one further switching parameter 22c of a further switching parameter set of the further branch switching unit 46c of the at least one further heating branch 42c to be operated.

[0063] The number of groups of heating units 14c and / or further heating units 44c may in particular differ from the number shown in this example; in particular, the cooking appliance 10c may have any number of groups 72c, 74c of heating units 14c and / or further heating units 44c. The number of heating units 14c and / or further heating units 44c that together form a group 72c, 74c may in particular differ from the number shown in this example; in particular, a group 72c, 74c may have any number of heating units 14c and / or further heating units 44c. Furthermore, the groups 72c, 74c of heating units 14c and / or further heating units 44c may differ from one another by a different number of heating units 14c and / or further heating units 44c. In addition, an arrangement of groups 72, 74c and / or an arrangement of heating units 14c and / or further heating units 44c may differ. Reference symbol

[0064] 10 Cooking appliance device 12 Heating branch 14 Heating unit 16 Branch switching unit 18 Common switching unit 20 Control unit 22 Switching parameters 24 Switch-on time 26 Switch-on duration 28 Common period 30 Branch diode 32 Cooktop 36 Resonance unit 38 Switching element 40 Cooling unit 42 Additional heating branch 44 Additional heating unit 46 Additional branch switching unit 48 Additional common switching unit 52 Capacitor 54 Parallel-connected branch switching diode 56 Parallel-connected diode 58 Waste heat 60 Heating power 62 Bus potential 64 Ground potential 66 Reference heating power 68 Reduced heating power 70 Heating zone 72 First group 74 Second group

Claims

1. Cooking appliance apparatus (10a-c), in particular hob apparatus, with a plurality of at least two heating branches (12a-c), each of which comprise at least one heating unit (14a-c) and at least one branch switching unit (16a-c), with a switching unit (18a-c) common to the heating branches (12a-c) and with at least one control unit (20a-c), which, in an operating state for adjusting a heating power of at least one of the heating branches (12a-c) to be operated, adapts at least one switching parameter (22a-c) of a set of switching parameters of the branch switching unit (16a-c) of the at least one heating branch (12-a-c) to be operated, wherein the control unit (20a-c) periodically operates the branch switching units (16a-c) of the heating branches 12a-c) to be operated with a common cycle duration (28a-c) in each case, characterised in that in the operating state the control unit (20a-c) operates the common switching unit (18a-c) periodically with the common cycle duration (28a-c).

2. Cooking appliance apparatus (10a-c), in particular hob apparatus according to claim 1, characterised in that the set of switching parameters comprises at least one switch-on time (24a-c) of the branch switching unit (16a-c) of the at least one heating branch (12a-c) to be operated.

3. Cooking appliance apparatus (10a-c), in particular hob apparatus according to one of the preceding claims, characterised in that the set of switching parameters comprises at least one switch-on duration (26a-c) of the branch switching unit (16a-c) of the at least one heating branch (12a-c) to be operated.

4. Cooking appliance apparatus (10a-c), in particular hob apparatus according to one of the preceding claims, characterised in that the control unit (20a-c) operates all of the branch switching units (16a-c) with a separate set of switching parameters.

5. Cooking appliance apparatus (10a-c), in particular hob apparatus according to one of the preceding claims, characterised in that the heating branches (12a-c) each have at least one branch diode (30a-c) which locks the heating branches (12a-c) with respect to one another.

6. Cooking appliance apparatus (10a-c), in particular hob apparatus according to claim 5, characterised in that the branch diodes (30a-c) are each arranged in front of the associated branch switching unit (16a-c) when viewed from the common switching unit (18a-c).

7. Cooking appliance apparatus (10a-c), in particular hob apparatus according to one of the preceding claims, characterised in that the heating branches (12a-c) each have at least one resonance unit (36a-c) which, with the associated heating units (14a-c), are part of a resonant circuit.

8. Cooking appliance apparatus (10a-c), in particular hob apparatus according to one of the preceding claims, characterised in that the common switching unit (18b) has at least two switching elements (38b) connected in parallel.

9. Cooking appliance apparatus (10a-c), in particular hob apparatus according to one of the preceding claims, characterised by a cooling unit (40a-c) which cools the common switching unit (18a-c) to a greater extent than the individual branch switching units (16a-c).

10. Cooking appliance apparatus (10a-c), in particular hob apparatus according to one of the preceding claims, characterised by a plurality of at least two additional heating branches (42c), each of which comprise at least one additional heating unit (44c) and at least one additional branch switching unit (46c), and an additional switching unit (48c) common to the additional heating branches (42c), wherein, in an operating state for adjusting a heating power of at least one of the additional heating branches (42c) to be operated, the control unit (20c) adapts at least one additional switching parameter of an additional set of switching parameters of the additional branch switching unit (46c) of the at least one additional heating branch (42c) to be operated.

11. Cooking appliance, in particular hob (32a-c) with at least one cooking appliance apparatus (10a-c) according to one of the preceding claims12. Method for operating a cooking appliance apparatus (10a-c), in particular hob apparatus, in particular according to one of claims 1 to 10, with a plurality of at least two heating branches (12a-c), each of which comprise at least one heating unit (14a-c) and at least one branch switching unit (16a-c) and with a switching unit (18a-c) common to the heating branches (12a-c), in which, for adjusting a heating power of at least one of the heating branches (12a-c) to be operated, at least one switching parameter (22a-c) of a set of switching parameters of the branch switching unit (16a-c) of the at least one heating branch (12a-c) to be operated is adapted, wherein the branch switching units (16a-c) of the heating branches (12a-c) to be operated are each operated periodically with a common cycle duration (28a-c), characterised in that the common switching unit (18a-c) is operated periodically with the common cycle duration (28a-c).