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

Abstract

The invention is based on an induction hob device (10a; 10b) with at least one induction unit (12a; 12b) operable by means of a main current from a main power supply unit (14a; 14b), and with at least one detection unit (16a; 16b) for detecting a mounting unit (72a) above the induction unit (12a; 12b). In order to increase detection precision and flexibility with regard to setting the step response, it is proposed that the detection be based on a step response generated at a zero crossing of the main current.

Description

[0001] The invention relates to an induction hob device according to the preamble of claim 1, an induction hob according to claim 11 and a method for operating an induction hob device according to claim 12.

[0002] An induction hob with cooking utensil detection is already known from the prior art, wherein the cooking utensil detection is based on an impedance change, dependent on the presence of a cooking utensil, at an induction coil through which a detection current flows in a detection state. The detection current is provided by a main current and the induction coil is provided for heating a cooking appliance by means of the main current in a heating state. EP 3598849 A1, EP 3651548 A1, EP 3598850 B1, KR 102453862 B1 show such a configuration, wherein the detection current is provided and, in particular, at least partially controlled by at least one inverter of the induction hob. Furthermore, the use of a step response for cooking utensil detection is known from EP 4037433 A1.Furthermore, from EP 3066888 A1 and WO 2021136306 A1, an embodiment is known in which a relay switches between a detection circuit for detecting the cooking utensil and a heating circuit for heating the cooking utensil.

[0003] The object of the invention is, in particular but not limited to, to provide a generic device with improved properties regarding detection precision and flexibility regarding step response adjustment. 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.

[0004] The invention relates to an induction hob device with at least one induction unit which can be operated by means of a main current of a main power supply unit, and with at least one detection unit for detecting a mounting unit above the induction unit.

[0005] It is proposed that the detection is based on a step response generated at a zero crossing of the main current.

[0006] Such a configuration can, in particular, increase the precision of detection, in particular by reducing electromagnetic interference signals, for example caused by electromagnetic interference with the main power supply unit and / or at least one element that can be supplied by the main current, for example an inverter or the like, during the generation of the step response, in particular due to the generation of the step response at the zero crossing of the main current. Furthermore, in particular at least one current intensity, in particular an initial current intensity, of the step response can advantageously be adjusted independently of the main current and in particular particularly flexibly. Advantageously, by means of the flexible adjustment of the initial current intensity, which correlates to an acoustic noise, operating comfort can be increased by advantageously reducing the acoustic noise.Furthermore, the cost efficiency of components of the detection unit can be advantageously increased, particularly compared to a configuration in which the step response is generated by means of the main current and the detection unit, in particular, must have components that are suitable for an applied voltage of the main current. Advantageously, the detection unit can have low-voltage and / or medium-voltage components, in particular low-voltage and / or medium-voltage transistors.

[0007] The induction hob device is in particular at least one part, in particular a subassembly, of an induction hob. The induction hob device preferably has at least one part of an electrical circuit and preferably the entire electrical circuit of the induction hob. The induction hob device and / or the induction hob preferably has / has at least one housing for accommodating the circuit and / or at least one user interface for controlling at least the circuit by an operator. The user interface preferably has at least one, in particular mechanical or digital, operating element for controlling the induction hob, in particular the induction hob device.Alternatively, it would be conceivable for the user interface to be formed separately from the induction hob, and in particular to be at least part of a smart device, for example a smartphone or a tablet, or at least part of a computer, in particular by means of a corresponding app. The induction hob device can comprise the entire induction hob. The induction hob preferably has a support plate for supporting the support unit. The induction unit is preferably arranged in an installation position below the support plate. The support plate can be formed as a hob plate. Alternatively, the support plate can be formed as a kitchen worktop.Preferably, the kitchen worktop, in particular in contrast to the hob plate, is additionally intended to provide a food preparation area in which, for example, cutting and / or mixing and / or pounding and / or peeling of food could be carried out.

[0008] The induction unit can be operated by means of the main current, preferably for an energy transfer of inductive energy from the induction unit to the installation unit, in particular for an inductive energy supply and / or an inductive heating of the installation unit, in particular in a transmission state. The induction unit can be operated by means of the main current, in particular for a cooking process on and / or in the installation unit. The induction unit preferably has at least one induction coil, above which the installation unit can be arranged for the energy transfer. Preferably, the induction unit has more than one induction coil, wherein in particular at least one induction coil can be assigned to at least one transmission zone, for example precisely one transmission zone, on the installation plate on which the installation unit can be arranged for the energy transfer.The "installation unit being arranged above the induction unit" should be understood in particular to mean that the installation unit is placed on the installation plate, in particular on the transmission zone of the installation plate, with the induction unit being arranged in particular below the installation plate, in particular at least below the transmission zone. Preferably, the induction hob device, in particular the induction hob, is provided for inductive energy supply to more than one installation unit and in particular for detection of more than one installation unit, with the induction hob in particular having more than one transmission zone. The induction hob can be designed as a matrix induction hob, in particular with a matrix-like distribution of the transmission zones and in particular of the induction coils. Alternatively, a discrete distribution of the transmission zones and in particular of the induction coils is conceivable.The main current is preferably designed as a mains current, and the main power supply unit is designed, in particular, as a network connection to a power transmission network. Alternatively, the main power supply unit can be designed as at least one generator or the like. The main power supply unit can be part of the induction hob device. The main current is designed, in particular, as an alternating current, wherein the zero crossing of the main current describes, in particular, the zero crossing of the alternating current. Preferably, the induction unit is operable by means of a supply current generated by means of the main current, wherein the induction unit, in particular the at least one induction coil, is provided for the supply current to flow through in order to emit the inductive energy for the energy transmission.The supply current is in particular designed as a main current that is at least filtered and / or rectified and / or smoothed and / or inverted by a bus capacitor, in particular by a smoothing capacitor. The bus capacitor is preferably at least substantially completely discharged during the generation of the step response, in particular at the time of generation of the step response, wherein the bus capacitor can have a residual voltage of a maximum of 20%, preferably of a maximum of 15%, and particularly preferably of a maximum of 10% of a maximum voltage of the bus capacitor in the transmission state at the zero crossing, in particular due to a technical limitation of a discharge of the bus capacitor. Electromagnetic interference signals can advantageously be further reduced during the generation of the step response, in particular due to electromagnetic coupling.Preferably, the induction hob device has a determination unit, in particular a main current determination unit, which is provided for determining the main current and in particular the zero crossing for controlling the generation of the step response at the zero crossing.

[0009] The installation unit is preferably designed as a cooking utensil, which can be heated in particular by means of the induction unit, or as a small household appliance, which can be heated in particular by means of the induction unit and / or supplied with energy for operating the small household appliance. The small household appliance is preferably designed to be portable and can in particular be transported manually by the operator. The small household appliance is preferably designed as a small cooking appliance, in particular as a small cooking appliance. The small household appliance can be designed, for example, as a rice cooker, an air fryer, a blender, a juicer, a food processor, a kettle, a coffee machine and / or the like.The detection of the installation unit above the induction unit is, in particular, at least a detection of the presence of the installation unit above the induction unit, whereby "detection of a presence" is to be understood, in particular, as a detection of an existing arrangement of the installation unit above the induction unit, as also a detection of an absence of the installation unit above the induction unit. The detection of the installation unit is preferably based on an impedance, in particular an inductance and / or a resistance, of at least part of the detection unit. In particular, at least one impedance, in particular an inductance and / or a resistance, of the induction coil depends on the presence, in particular on a degree of coverage, of the installation unit above the induction coil.The degree of coverage preferably characterizes an area coverage of the transmission zone by means of the installation unit and can be dependent on a material of the installation unit. The detection unit is provided in particular for detecting the presence of the installation unit above the induction unit and / or for detecting the degree of coverage and / or for detecting a type of installation unit, for example as a cooking utensil or as a small household appliance. The induction unit, in particular the at least one induction coil, is preferably part of the at least one detection unit, wherein the induction coil in the detection unit preferably functions as a detection sensor. Preferably, the induction unit, in particular the at least one induction coil, is provided in a detection state for emitting at least one detection signal, in particular provided by means of the step response.The detection state and the transmission state preferably differ from one another and, in particular, each occur at a separate time. The induction hob device preferably has more than one detection unit, in particular one detection unit for each induction coil and / or each transmission zone. Detection by means of the respective detection units can preferably be carried out independently of one another. The detection can preferably be carried out by means of the detection unit assigned to a first induction coil simultaneously with an energy transmission, in particular for heating and / or energy supply, from a second induction coil, for example also a second induction coil adjacent to the first induction coil.Different induction coils of the induction unit can simultaneously have different states, in particular the transmission state or the detection state or a deactivated state in which, in particular, no current flows through the induction coil. Alternatively, it is conceivable that the detection units are only provided for simultaneous detection. Preferably, the at least one detection unit, in particular a plurality of detection units, is provided for detecting a position of the installation unit on the induction hob, in particular by the detection being able to be carried out in the induction hob taking into account a position of the induction coil above which the installation unit is detected, wherein preferably a position of the induction coil in the induction hob, in particular at least a relative distribution of the induction coils to one another, is stored.

[0010] The step response is designed in particular as a response signal to an exciting step signal, wherein the step signal describes a step function which jumps between zero and a predetermined deflection value not equal to zero. The step signal is designed in particular as a rectangular pulse. Preferably, the step signal has a jump from the deflection value to zero at the zero crossing. In the detection state, the step response is preferably present in at least part of the induction unit, in particular at least in the induction coil. The step response, in particular a temporal profile of the step response, depends in particular on the impedance, in particular the inductance and / or the resistance, of the induction coil. The step response, in particular the temporal profile of the step response, depends in particular on the presence of the installation unit, in particular on the degree of coverage.The induction hob, in particular the induction hob device, preferably has at least one control unit for controlling the jump signal. The control unit is preferably provided for switching between the detection state and the transmission state. The control unit can also be provided for controlling an inverter of the induction hob, in particular the induction hob device. The control unit can be provided for a main power supply at least for the induction unit and in particular for controlling, in particular regulating, the energy transmission emanating from the induction unit in the transmission state. The control unit can be at least partially part of the detection unit. The control unit can preferably be controlled and, in particular, adjustable by the operator using the user interface, in particular using the at least one operating element.The control unit is preferably configured to evaluate the step response for detecting the installation unit. The control unit is preferably configured to output the detected presence of the installation unit and / or the detected degree of coverage to the operator at the operator interface, in particular at a display unit of the operator interface.Preferably, the presence of the installation unit and in particular the position of the installation unit on the induction hob can be output at the user interface, in particular at the display unit of the user interface, wherein the display unit can, for example, have at least one display sub-unit and / or at least one display sub-area which is assigned to exactly one transmission zone, wherein in particular the respective display sub-unit and / or the respective display sub-area can be activated, in particular at least illuminated, when the presence of the installation unit on the corresponding transmission zone is detected and is in particular provided for display.The control unit is preferably provided for deactivating, in particular at least dimming, the display of the display sub-unit and / or the display sub-area, in particular immediately after a transfer zone change or removal of the installation unit from the induction hob. The control unit is preferably provided for deactivating a display sub-unit and / or a display sub-area of ​​an assigned transfer zone, from which the installation unit is removed when the installation unit is changed to a new transfer zone, before activating a display sub-unit assigned to the new transfer zone and / or a display sub-area assigned to the new transfer zone. The display unit preferably has at least one display element, in particular at least one lighting element and / or a display.The user interface can, for example, have at least one touchscreen for providing the at least one control element and the display unit, wherein a respective control element can be displayed on the touchscreen when the presence of the installation unit is detected in an arrangement corresponding to the position of the installation unit on the induction hob and, in particular, can be activated for adjustment by the operator. In particular, security can be increased if the control element assigned to a transmission zone can only be adjusted for a detected presence of the installation unit on the transmission zone. The control unit is preferably provided to automatically throttle or block a main power supply of the induction unit, in particular of the induction coil, above which an absence of the installation unit is detected, in particular after a predetermined time or directly after detection.The control unit is preferably provided to release a main power supply of the induction unit, in particular of the induction coil, above which the presence of the installation unit is detected.

[0011] "Intended" means specifically programmed, designed, and / or equipped. An object being intended for a specific function means that the object fulfills and / or performs that specific function in at least one application and / or operating state.

[0012] It is further proposed that the detection unit have a power supply unit for providing a step signal, in particular the above-mentioned one, for exciting the step response. In particular, the step response, in particular a current for generating the step response, can advantageously be provided at the zero crossing of the main current. Energy of the step signal and thus in particular of the step response is preferably provided only by the power supply unit. The power supply unit differs in particular from the main power supply unit, wherein a current of the power supply unit can be provided in particular independently of the main current. The step response is preferably provided by means of an exciting current of the power supply unit. The step signal preferably has the exciting current and is in particular designed as this.The power supply unit in particular provides a voltage lower than a voltage of the main power supply unit. The excitation current emanating from the power supply unit can have a smaller average current than the main current, whereby the precision of the detection can advantageously be increased. In particular, even small changes in the current strength of the excitation current can be determined. The power supply unit can be provided to supply power to the user interface, whereby the user interface can be operated particularly advantageously independently of the main current. Preferably, the power supply unit has at least one, in particular mechanical, power supply unit switch, by means of which the power supply unit and thus in particular the user interface can be switched on and off, in particular independently of the main current.The power supply unit switch can, for example, function as an on / off switch for the induction hob. The power supply unit is preferably provided for at least partially supplying power to the control unit, wherein the control unit is in particular operable independently of the main power. Advantageously, after the induction hob has been switched on, prior to a first transmission state, the installation unit can be detected and, in particular, a result of the detection can be output at the user interface, whereby, in particular, the transmission state can be set at the user interface. Preferably, the detection unit is provided at least for detecting the installation unit immediately after the power supply unit switch has been switched on and / or the induction hob has been switched on.The detection unit is preferably provided for, in particular periodically, repeated detection of the installation unit after the power supply unit switch has been switched on and / or after the induction hob has been switched on until the power supply unit switch has been switched off and / or after the induction hob has been switched off, in particular also after the start of the transmission state, whereby removal of the installation unit from the induction hob or a change in position of the installation unit on the induction hob can advantageously be detected by means of the detection unit. Alternatively, it is conceivable that the user interface and / or the control unit can be operated by means of at least one further power supply unit and / or at least partially by means of the main power. The power supply unit is preferably provided for providing, in particular outputting, a direct current.The power supply unit preferably provides a voltage between 1 V and 100 V, for example, exactly 24 V. Alternatively, a higher or lower voltage would also be conceivable for certain configurations, particularly depending on the number and type of units and / or elements of the induction hob that can be supplied by the power supply unit. Alternatively, it would be conceivable for the power supply unit to provide an alternating current.

[0013] It is also proposed that the excitation of the step response be generated independently of an inverter, in particular the one mentioned above, whereby electromagnetic interference with at least the inverter in the detection state, in particular during excitation of the step response, can be reduced or avoided. The detection unit preferably has at least one circuit external to a circuit for energy transmission in the transmission state, which circuit can be connected to at least part of the circuit, in particular at least the induction coil, in at least the detection state. The excitation can be generated independently of the bus capacitor, in particular independently of a charge of the bus capacitor.

[0014] It is further proposed that the induction unit comprise at least one induction coil, in particular the one mentioned above, wherein a step signal for exciting the step response can be generated by charging the induction coil with current. The step signal can be provided particularly advantageously in the induction coil, wherein in particular the impedance, in particular the inductance and / or the resistance, of the induction coil can particularly efficiently influence the step response in the induction coil. The induction coil can be charged, in particular in the detection state, preferably by the excitation current, in particular by the step signal, originating from the power supply unit.

[0015] Alternatively, it would be conceivable that the step signal for exciting the step response could be generated by charging at least one resonance capacitance of the induction hob device with voltage.

[0016] It is further proposed that the detection unit have at least one, in particular unidirectional, switch for controlling the charging process. In particular, the charging process can advantageously be controlled by means of the switch. By means of the unidirectional switch, in particular, an unwanted backflow of a current through the switch during charging and in particular outside of charging can advantageously be avoided. The unidirectional switch is provided, in particular in a closed state, preferably to allow the step signal, in particular the excitation current, to pass in a charging direction and in particular, preferably also in an open state of the switch, to block a current flow opposite to the charging direction.The switch in particular has at least one switching element, which is preferably designed as a semiconductor switching element, preferably as a MOSFET switching element and particularly preferably as a PMOS switching element, wherein in particular precise control of the switching element can be achieved and / or operating comfort can be advantageously increased, for example through particularly quiet switching of the switching element, in particular compared to a relay switching element. Alternatively, however, the semiconductor switching element can have any switch polarity, in particular P, N, PNP, NPN or the like, and in particular can be designed as any semiconductor switching element that appears appropriate to a person skilled in the art, for example as a bipolar transistor.Alternatively, it would be conceivable for the switching element to be designed as a relay switching element or as another switching element that would appear appropriate to a person skilled in the art and that differs from a semiconductor switching element. Advantageously, however, the switch is designed free of a relay switching element and, in particular, the charging can be controlled and, in particular, carried out free of a relay switching element. The switch preferably has at least one unidirectional element, for example a rectifying element, in particular a diode, which is, in particular, connected in series with the switching element. The switching element can have an intrinsic diode that has a forward direction opposite to the charging direction and, in particular, provides a return flow opposite to the charging direction, in particular when the switching element is open.The unidirectional element is preferably provided to block the return flow counter to the charging direction, preferably during charging and outside of charging, in particular during the step response and / or during the transfer state, in particular for the open switching element. Alternatively, any known unidirectional switch deemed appropriate by a person skilled in the art would be conceivable. The switch is preferably interposed between the power supply unit and the induction coil. The induction coil is preferably chargeable while the switch, in particular the switching element, is closed, in particular using the current from the power supply unit. The switch preferably electrically connects the induction coil to the power supply unit in the closed state.The control unit is preferably provided for controlling the switch, in particular the switching element, and in particular the jump signal and the charging. The induction hob device, in particular the detection unit, preferably has at least one gate driver, in particular a non-inverting gate driver, for controlling the switch, in particular the switching element. The control unit is preferably provided for controlling the switch, in particular the switching element, in particular via the gate driver. The control unit is preferably provided for controlling the gate driver. The control unit is preferably provided, in particular by means of the gate driver, to control the switch, in particular the switching element, before the zero crossing of the main current, in particular milliseconds before the zero crossing of the main current, to close the switch for charging.A predetermined charging duration is preferably stored, in particular in the control unit. The charging duration corresponds in particular to a pulse duration of the jump signal. The control unit is preferably provided to open the switch, in particular the switching element, in particular after the charging duration has elapsed, to stop charging. The induction coil can preferably be discharged immediately after charging is complete, in particular when the switch, in particular the switching element, is in an open state. The control unit is particularly provided to open the switch, in particular the switching element, when the main current passes through zero. The induction coil can preferably be discharged by means of a damped oscillation, in particular in an oscillating circuit comprising at least the induction coil and the at least one resonant capacitor of the induction hob device.The step response is preferably designed as the damped oscillation of a current intensity. The oscillation, in particular the step response, is preferably designed as a free oscillation, in particular different from a driven oscillation. Preferably, the switch, in particular the switching element, is open during discharging, in particular during the oscillation of the step response, wherein in particular a current transfer from the power supply unit is interrupted. The damped oscillation, in particular the step response, is preferably damped due to losses, in particular resistance losses, in the electrical and / or electronic components of the resonant circuit. The oscillation corresponds in particular to a second-order oscillation. A current intensity, in particular an amplitude, of the step response is particularly dependent on the charging duration, in particular the pulse duration of the step signal.Preferably, an initial current strength, in particular an initial amplitude, of the step response is dependent on the charging duration, in particular the pulse duration of the step signal. The current strength, in particular the initial current strength, of the step response increases in particular with an increasing charging duration. The initial current strength is preferably a maximum current strength of the step response, which is present in particular at an initial time of the step response after the generation of the step response. An acoustic noise during the generation of the step response increases in particular with the initial current strength. Advantageously, an optimized trade-off between the acoustic noise and detection precision, which increases in particular with an increasing initial current strength, can be achieved by precisely adjusting the initial intensity using the switch.The resonance capacitance is preferably provided in the transmission state for further oscillation with the induction coil for energy transmission to the installation unit. The induction hob device preferably has at least two, and preferably exactly two, resonance capacitances, in particular a high-side resonance capacitance and a low-side resonance capacitance. The step signal and in particular a charging path preferably cross a connection, in particular a center point, of the resonance capacitances.

[0017] It is also proposed that the detection unit have at least one throttle unit for throttling the charging. The charging time can advantageously be increased while maintaining a constant current strength, in particular the constant initial current strength, of the step response. In particular, the predetermined, in particular the stored charging time for generating a predetermined initial current strength of the step response depends on the throttle unit, in particular on an inductance of the throttle unit. The charging time for a suitable charge level of the induction coils is particularly short without the use of the throttle unit, for example, shorter than 500 µs, in particular shorter than 200 µs, whereby a small deviation in the charging time of just a few µs can lead to different excitation results.Advantageously, the charge state of the induction coil and thus in particular the current intensity, in particular the initial current intensity, of the step response can be adjusted more precisely due to the increased charging time as a function of the charging time. The choke unit is preferably interposed between the power supply unit and the induction unit, in particular the induction coil, whereby the choke unit can advantageously throttle the current, in particular the excitation current, for charging the induction coil. The choke unit is preferably connected directly downstream of the power supply unit. The choke unit is preferably interposed between the power supply unit and the switch for controlling the charging, in particular the step signal. The choke unit has in particular an inductance for throttling the excitation current, in particular the step signal.The inductance of the choke unit can, for example, have a value of at least 5 mH, preferably of at least 7 mH, and preferably of at least or exactly 10 mH. The inductance of the choke unit is preferably greater than an inductance of the induction coil. A current intensity of a charged current in the induction coil, in particular the initial current intensity of the response signal, in particular has an exponential relationship with respect to the charging time, wherein at least one time constant of the exponential relationship is dependent on a total resistance. R Charging = R Induction coil + R Switch of a charging circuit, which in particular at least a sum of a resistance R Induction coil of the induction coil and a resistor R Schaller of the switch, and of a total inductance L Charging = L Induction coil + LThrottle unit ~ L Choke unit, which in particular is a buzzer of the inductance L Induction coil of the induction coil and the inductance LChoke unit corresponds to the choke unit. The charged current, in particular the initial current strength of the response signal, preferably increases with the charging duration, in particular the pulse duration of the step signal, wherein a gradient of the charged current decreases with the charging duration. The choke unit can have at least one electrical choke, in particular at least one choke coil, and for example at least one freewheeling diode of the choke coil. In particular, the choke unit can have exactly one choke coil and for example exactly one freewheeling diode. The choke unit having the choke coil is designed in particular as a passive circuit. Advantageously, a choke unit with particularly low complexity can be achieved. The choke coil preferably has a saturation current strength of several amperes, in particular at least 1 A, preferably at least 2 A, preferably at least 3 A and particularly preferably at least 4 A.The choke unit preferably has at least one heat resistance, in particular a mechanical heat resistance and / or a heat resistance with regard to the properties of the choke unit, for example a heat resistance with regard to the inductance and / or the saturation current of the choke unit, in particular of the choke coil, with respect to the temperatures typical for induction heating, in particular at least 100°C.

[0018] It is further proposed that the choke unit comprise at least one gyrator. In particular, the above-mentioned requirements with regard to inductance, an excitation current to be throttled, and heat resistance can be advantageously met, in particular with increased cost and / or space efficiency of the choke unit with the gyrator compared to the design of the choke unit with the choke coil. The choke unit with the gyrator is in particular designed without a coil element, in particular a choke coil. The gyrator can in particular simulate, in particular emulate, a choke coil with optimized properties, in particular with regard to inductance, the excitation current to be throttled, and heat resistance. The choke unit can be designed as the gyrator.The choke unit, in particular the gyrator of the choke unit, preferably has at least one resistance element and at least one capacitance element, which are connected in particular to an inductive input behavior. The choke unit, in particular the gyrator, can, for example, have exactly one capacitance element and more than one resistance element. The capacitance element preferably has a capacitance in the µF order of magnitude, for example with a value of 1 µF. The capacitance element is preferably designed as a capacitor, in particular as a ceramic capacitor. Preferably, the predetermined, in particular the stored, charging time for generating the predetermined initial current strength of the step response is dependent on the capacitance of the capacitance element. The choke unit, in particular having the gyrator, is preferably designed as an active circuit.The throttle unit, in particular comprising the gyrator, preferably has at least one throttle switching element, preferably a semiconductor switching element, in particular a transistor, advantageously a transistor for low voltages, for example a low voltage of 30 V.

[0019] It is further proposed that the detection of the installation unit be based on determining a decay constant of a damped oscillation, in particular of the above-mentioned, of the step response. In this way, the installation unit can advantageously be detected based on the step response, wherein in particular a particularly precise evaluation of the step response can be achieved. Advantageously, the detection can be carried out solely on the basis of a relative comparison of various values, in particular the maxima and / or minima, of the step response, whereby in particular a calculation for detecting the installation unit can be carried out without taking into account multiplication, for example due to amplification, or the like. Advantageously, a determination of the absolute current intensity of the step response and / or absolute values ​​of the current intensity of the step response is not necessary.In particular, a determination, in particular a measurement, of the current intensity of the step response can be advantageously simplified. The decay constant can preferably be determined based on at least two current intensities of the step response, in particular based on a ratio of the current intensities at at least two extreme points, preferably at two, in particular immediately consecutive, minima and / or maxima of the step response. Preferably, a respective current intensity . l i of the step response at a time t i can be described by means of an equation, in particular a known one, for describing a damped oscillation oscillating in an oscillating circuit I i = I max ⋅ sin ω n t i e − αt i with a frequency ω n = 2 π τ n = ω o 2 − α 2 , where ω 0 = 1 LC the natural frequency, α = R 2 L the decay constant, T n the period duration, Ra resistance, C a capacitance, in particular of the at least one resonance capacitance, L an inductance, in particular at least of the induction coil, of the resonant circuit in which the response signal oscillates, and I max describes the initial current at the beginning of the discharge, in particular at the beginning of the oscillation, at a time t 0 = 0 ms. The inductance L and in particular the resistance Rof the resonant circuit depend in particular on the presence, in particular on the degree of coverage, of the installation unit. The decay constant is in particular inversely proportional to the effective inductance of the induction coil and in particular proportional to the effective resistance. Preferably, the decay constant can be determined based on current intensities of the at least two maxima and / or minima of the step response, and in particular the associated times of the at least two maxima and / or minima, and thus in particular the installation unit, preferably based on an evaluation of the inductance L and / or the resistance R based on the determined decay constant. In particular, a ratio of the currents l 1 , l 2 of at least two consecutive maxima and / or minima, at the respective times t 1 , t 2 ,which in particular has a time difference of one period T n to each other, can advantageously be shortened to: I 1 I 2 = e − αt 1 e − αt 2 , where in particular the decay constant is determined using the equation α = ln I 1 / I 2 t 2 − t 1 can be determined. It is conceivable that more than two maxima and / or minima of the step response are evaluated to determine the decay constant, in particular to increase the precision of the determined decay constant. Alternatively or additionally, the decay constant can be determined based on the frequency ω n of the step response, in particular the oscillation.

[0020] It is also proposed that the detection unit have at least one high-pass filter for determining, in particular for measuring and / or estimating, the step response, whereby the step response can be determined in a particularly cost-effective and / or simple manner. Advantageously, the cost efficiency and / or space efficiency of the induction hob device can be increased. The step response determined by means of the high-pass filter deviates, in particular, at least partially from an actually existing step response and in particular from a step response determined by means of a precise measuring method for an alternating current, for example a Rogowski coil or the like. Preferably, the current intensity of the step response determined by means of the high-pass filter has a precision sufficient at least for detecting the installation unit, in particular for determining the decay constant.The decay constant can be determined in particular based on the relative comparison of the at least two current intensities of the step response determined by means of the high-pass filter, wherein the relative comparison is in particular independent of an amplification, in particular a gain, of the determination by means of the high-pass filter. The high-pass filter is preferably provided for determining a capacitance voltage across the at least one resonance capacitance, in particular the low-side resonance capacitance, for determining the step response, in particular for determining the current intensity of the step response, wherein the capacitance voltage is in particular proportional to the current intensity of the step response. The high-pass filter is in particular provided for providing a measurement signal correlated with the step signal on the basis of the determined capacitance voltage.The control unit is preferably provided for determining the step response, in particular based on a measurement signal from the high-pass filter. The control unit is particularly provided for evaluating the measurement signal from the high-pass filter to determine the current strength of the step response. The step response can be determined by means of the high-pass filter, preferably in accordance with the determination of the heating current in EP 3337293 A1. Alternatively or additionally, it is conceivable for the detection unit to have at least one other measuring unit known to those skilled in the art for determining the step response, in particular the alternating current of the oscillation of the step response, for example a Rogowski coil or the like.

[0021] The induction hob device preferably comprises the inverter. The inverter preferably comprises at least two inverter switches, in particular a low-side switch and a high-side switch. It would be conceivable for the resonant circuit to comprise the at least one inverter switch, in particular at least the low-side switch, for oscillating the step response. The inverter switch is designed in particular as a semiconductor switch, preferably as an IGBT, a bipolar transistor with an insulated gate electrode, or as another inverter switch known to those skilled in the art. The inverter switch additionally dampens the step response, in particular due to a voltage drop and / or damping at a protective diode, in particular an anti-parallel one, of the inverter switch.The inverter, in particular the inverter switch, increases the resistance in the resonant circuit in which the step response oscillates, wherein the resistance offset provided by the inverter, in particular the inverter switch, is dependent in particular on at least one unpredictable parameter, which may depend, for example, on a production batch of the inverter switch and / or a temperature. Thus, a passage of the step signal through the inverter, in particular the inverter switch, is preferably avoided.In a preferred embodiment of the invention, it is proposed that the induction hob device has an inverter, in particular the one mentioned above, wherein the detection unit has at least one relay for short-circuit bridging at least part of the inverter, in particular the at least one inverter switch of the inverter, during determination of the step response. Advantageously, the precision and / or reliability of the determined step response can be increased. In particular, additional, in particular unpredictable, attenuation of the step response in the oscillating circuit can be advantageously reduced or avoided. By means of the short-circuit bridging, in particular a resistance of the bridging can be advantageously reduced. The oscillating circuit is preferably designed to oscillate the step response free of the inverter, in particular the at least one inverter switch.The relay preferably bridges the low-side switch, wherein the resonant circuit is in particular designed free of the high-side switch. The resonant circuit preferably comprises the relay. The relay is in particular provided in a closed state to form the short-circuit bridging. The control unit is preferably provided to control the relay. The control unit is preferably provided to close the relay at least during the determination of the step response, in particular at least during the oscillation of the step response. The control unit is preferably provided to open the relay at least in the transmission state and in particular to cancel the short-circuit bridging. Alternatively, a different short-circuit bridging would be conceivable, for example by means of a different switch that appears appropriate to a person skilled in the art.

[0022] Furthermore, a method for operating an induction hob device, in particular the one mentioned above, with an induction unit, in particular the one mentioned above, which can be operated by means of a main current, in particular the one mentioned above, is proposed, wherein a setup unit, in particular the one mentioned above, above the induction unit is recognizable based on a step response, in particular the one mentioned above, generated at a zero crossing of the main current, in particular the one mentioned above. Advantageously, a precision of the detection and / or flexibility in adjusting the step response and / or ease of use, in particular with regard to an acoustic noise mentioned above, and / or cost-effectiveness of the induction hob device can be increased.

[0023] The method preferably comprises a method step, in particular a charging step, in which an induction coil, in particular the above-mentioned one, is charged. Preferably, a switch, in particular the above-mentioned one, of the detection unit is closed in the charging step, in particular during the entire charging step. Preferably, the switch, in particular in the charging step, connects the induction coil to a power supply unit, in particular the above-mentioned one, for current transmission from the power supply unit to the induction coil, in particular for charging the induction coil. An excitation current, in particular the above-mentioned one, for charging the induction coil is preferably designed as a step signal, in particular the above-mentioned one. The method preferably comprises at least one further method step, in particular a discharging step, in which the induction coil is discharged.The induction coil is preferably discharged, particularly in the discharging step, by means of the step response, which is particularly designed as a damped free oscillation of at least one current strength. The step response is preferably generated in the discharging step. The discharging step begins, particularly at the zero crossing of the main current. The discharging step preferably takes place, particularly immediately, after the charging step. The switch of the detection unit is, in particular, in an open state in the discharging step. Preferably, particularly in the discharging step, advantageously by means of a control unit, in particular the above-mentioned oscillating circuit, is provided for executing the oscillation of the step response. The step response is preferably determined, in particular measured and / or estimated, particularly in the discharging step.The method preferably comprises at least one evaluation step in which the step response is evaluated. The evaluation step preferably takes place at least partially after the discharge step and / or at least partially simultaneously with the discharge step. Preferably, in particular in the evaluation step, a decay constant of the step response, in particular the one mentioned above, is determined. The presence of the installation unit above the induction unit is detected, in particular in the evaluation step, based on the decay constant.

[0024] The induction hob device, the induction hob, and the method for operating the induction hob device are not intended to be limited to the application and embodiment described above. In particular, the induction hob device, the induction hob, and the method for operating the induction hob device 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.

[0025] 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.

[0026] They show: Fig. 1A schematic representation of an induction hob with a mounting unit arranged thereon, Fig. 2A circuit diagram of an induction hob device of the induction hob with at least one induction coil and with a detection unit for detecting the mounting unit by means of a step response, Fig. 3An exemplary graph of a charged current in the induction coil over a charging time of the induction coil, Fig. 4A graph of an exemplary step response, Fig. 5Exemplary graphs of the step response for (a) a first charging time and (b) a second charging time, Fig. 6Exemplary graphs of the step response for (a) an absence of the mounting unit and (b) a presence of the mounting unit, Fig.7 exemplary graphs of an inductance versus a resistance of an oscillating circuit in which the step response oscillates, wherein the oscillating circuit (a) has a relay for short-circuit bridging and (b) is designed free of the relay, Fig. 8 flowchart of a method for operating the induction hob device and Fig. 9 a circuit diagram of an alternative induction hob device. .

[0027] Figure 1 shows a schematic representation of a top view of an induction hob 70a. The induction hob 70a is provided for inductive energy transfer, in particular for inductive heating and / or inductive energy supply, of a mounting unit 72a.

[0028] The installation unit 72a is embodied, for example, as a cooking utensil 74a. The induction hob 70a is provided for the inductive heating of the installation unit 72a embodied as the cooking utensil 74a. Alternatively, the installation unit 72a can be embodied as a small household appliance (not shown), for example as a rice cooker, a blender, or the like.

[0029] The induction hob 70a has a mounting plate 76a. The mounting plate 76a is provided for mounting the at least one mounting unit 72a, at least for the inductive energy transfer.

[0030] The induction hob 70a has a user interface 78a. The energy transfer can be adjusted by means of the user interface 78a by an operator (not shown) of the induction hob 70a. The user interface 78a has, in particular, at least one operating element 80a for adjusting the energy transfer. The operating element 80a is assigned to precisely one transmission zone 82a of the induction hob 70a. The user interface 78a is provided for outputting, in particular displaying, at least one item of information relating to the induction hob 70a and / or the installation unit 72a to the operator. The user interface 78a is embodied, for example, as a touchscreen. The operating element 80a is embodied here as a controller on the touchscreen. Alternatively, another configuration of the user interface 78a and, in particular, of the operating element 80a is conceivable.

[0031] The induction hob 70a has an induction hob device 10a. The induction hob device 10a is configured as at least part of an electrical and / or electronic circuit 20a of the induction hob 70a. In the present case, the induction hob device 10a is configured as the entire circuit 20a of the induction hob 70a. Alternatively, it would be conceivable for the induction hob device 10a to comprise further parts of the induction hob 70a, for example, the mounting plate 76a or the like, and / or the entire induction hob 70a, or merely a part of the circuit 20a.

[0032] Figure 2shows an at least partially simplified circuit diagram of the induction hob device 10a. The induction hob device 10a has at least one induction unit 12a. The induction unit 12a is designed to emit electromagnetic radiation for energy transfer. The induction unit 12a is arranged below the mounting plate 76a.

[0033] The induction unit 12a has at least one induction coil 22a. The induction coil 22a can be assigned to the transmission zone 82a of the induction hob 70a and, in particular, provides the transmission zone 82a (see Figure 1 ). The induction coil 22a is arranged below the transfer zone 82a. The transfer zone 82a is formed as an area on the induction hob 70a on which the mounting unit 72a can be placed, at least for energy transfer.

[0034] The induction unit 12a has more than one induction coil 22a. The induction hob 70a has more than one transmission zone 82a, wherein each induction coil 22a can be assigned to at least one or exactly one transmission zone 82a. Alternatively, it would be conceivable for the induction unit 12a to have only one induction coil 22a and, in particular, to provide only one transmission zone 82a.

[0035] The induction unit 12a, in particular the at least one induction coil 22a, is operable by means of a main current of a main power supply unit 14a. The induction unit 12a is operable by means of the main current for energy transfer. The induction unit 12a is intended to be operated by means of the main current for energy transfer. The main power supply unit 14a is presently part of the induction hob device 10a. Alternatively, the induction hob device 10a can be designed independently of the main power supply unit 14a.

[0036] The main current is configured as a mains current. The main power supply unit 14a is configured as a grid connection to a power transmission network. Alternatively, it would be conceivable for the main power supply unit 14a to be configured as a generator or the like.

[0037] The induction unit 12a is designed to be directly supplied to the energy transfer device by a supply current provided by the main current. The induction unit 12a is operable via the supply current by means of the main current.

[0038] The induction hob device 10a has at least one filter unit 84a. The filter unit 84a is designed as a filter unit known to those skilled in the art, in particular as an EMC filter unit. The filter unit 84a is provided for filtering the main current for generating the supply current.

[0039] The induction hob device 10a has at least one rectifier 86a. The rectifier 86a is designed as a bridge rectifier. The filter unit 84a is provided for rectifying the, in particular filtered, main current to generate the supply current.

[0040] The induction hob device 10a has at least one bus capacitor 88a. The bus capacitor 88a is designed as a smoothing capacitor. The bus capacitor 88a is provided at least for smoothing the rectified and, in particular, filtered main current for generating the supply current.

[0041] The induction hob device 10a has at least one inverter 24a. The inverter 24a has at least one inverter switch 54a. In this case, the inverter 24a has exactly two inverter switches 54a, in particular a low-side inverter switch 54a and a high-side inverter switch 54a, with only the low-side inverter switch 54a being designated here. The inverter switch 54a is designed as an IGBT switch. The inverter 24a is provided for inverting the rectified and, in particular, filtered and smoothed main current to generate the supply current.

[0042] The induction hob device 10a has at least one control unit 90a. The control unit 90a is provided at least for controlling the inverter 24a, in particular the at least one inverter switch 54a. The control unit 90a is adjustable via the user interface 78a, in particular at least for adjusting the energy transfer.

[0043] The induction hob device 10a has at least one resonance capacitance 92a. The supply current oscillates for energy transfer at least in the resonance capacitance 92a and in the induction coil 22a. The induction hob device 10a has precisely two resonance capacitances 92a, with only one resonance capacitance 92a, in particular a low-side resonance capacitance 92a, being designated.

[0044] The induction hob device 10a has at least one snubber 96a, in particular designed as a snubber capacitor. In the present case, the induction hob device 10a has exactly two snubbers 96a, with only one snubber 96a being designated.

[0045] The induction hob device 10a has at least one detection unit 16a for detecting the installation unit 72a above the induction unit 12a. The at least one detection unit 16a is provided for detecting the presence of the installation unit 72a above the induction unit 12a. The at least one detection unit 16a is provided for detecting the installation unit 72a above the at least one induction coil 22a. The at least one detection unit 16a is provided for detecting the degree of coverage of the transmission zone 82a by the installation unit 72a above the at least one induction coil 22a.

[0046] The induction coil 22a is part of the detection unit 16a. The induction coil 22a functions as a detection sensor in the detection unit 16a. The detection of the installation unit 72a is based on the dependence of an impedance, in particular an inductance and / or a resistance, of the induction coil 22a on the presence, in particular the degree of coverage, of the installation unit 72a above the induction coil 22a.

[0047] The at least one detection unit 16a is provided for detecting a position of the installation unit 72a on the induction hob 70a. The at least one detection unit 16a is provided for detecting the position of the installation unit 72a relative to the different transmission zones 82a. The induction hob device 10a preferably has a detection unit 16a for each induction coil 22a of the induction unit 12a and / or each transmission zone 82a of the induction hob 70a.

[0048] The control unit 90a is provided for outputting a detection result to the operator via the operator interface 78a. The control unit 90a is provided here for illuminating and / or activating an operating element 80a, in particular the controller, for controlling an energy transfer by means of an induction coil 22a, above which the presence of the installation unit 72a was detected (see FIG. Figure 1 ). Alternatively, a different output of the recognition result would be conceivable, in particular for a different design of the user interface 78a.

[0049] The induction hob device 10a has connections 98a, shown in dashed lines, to at least one further bus capacitor (not shown), to which in particular a subcircuit (not shown) is connected, which is designed corresponding to the part of the circuit 20a shown to the right of the bus capacitor 88a and which in particular has a further induction coil (not shown) of the induction unit 12a and a further detection unit (not shown).

[0050] Detection is based on a step response generated at a zero crossing of the main current. Detection of the positioning unit 72a is based on a dependence of the step response on the presence, in particular the degree of coverage, of the positioning unit 72a above the induction coil 22a. Detection of the positioning unit 72a is based on a dependence of the step response on the impedance, in particular an inductance and / or a resistance, of the induction coil 22a.

[0051] The detection unit 16a has a power supply unit 18a for providing a step signal to stimulate the step response. The step signal is supplied with power solely by the power supply unit 18a. The power supply unit 18a differs from the main power supply unit 14a. The power of the power supply unit 18a can be provided independently of the main power.

[0052] The power supply unit 18a is provided to supply power to the operator interface 78a and the control unit 90a. Alternatively, it is conceivable that the operator interface 78a and / or the control unit 90a can be operated by at least one further power supply unit 18a and / or at least partially by the main power.

[0053] The excitation of the step response can be generated independently by the inverter 24a. The step signal can be generated independently by the inverter 24a. The excitation, in particular the step signal, can be generated independently by the bus capacitor 88a. The excitation, in particular the step signal, can be generated independently of a charge on the bus capacitor 88a. The bus capacitor 88a is at least substantially discharged when the step response is generated. Alternatively, it would be conceivable for the bus capacitor 88a to be charged when the step response is generated.

[0054] The step signal for exciting the step response can be generated by charging the induction coil 22a with current, in particular the excitation current. The step signal is generated, in particular formed, by the excitation current.

[0055] The control unit 90a is provided to charge the induction coil 22a for a period of time corresponding to a charging duration, in particular stored in the control unit 90a. The step response, in particular at least an initial current strength of the step response, depends on the charging duration. The step response, in particular the initial current strength, increases with an increasing charging duration. The charging duration corresponds to a pulse duration of the step signal.

[0056] The detection unit 16a has at least one switch 26a for controlling the charging process. The switch 26a is designed as a unidirectional switch 26a. The charging process can be controlled by the switch 26a. The unidirectional switch 26a is provided to block a current that is opposite to a charging direction 40a.

[0057] The switch 26a has at least one switching element 36a. The switching element 36a is embodied as a semiconductor switching element 46a. The switching element 36a is embodied as a MOSFET switching element. The switching element 36a is embodied as a PMOS switching element. Alternatively, the switching element 36a can have any switch polarity and, in particular, can be embodied as any semiconductor switching element 46a that appears appropriate to one skilled in the art, for example, as a bipolar transistor, or as a switching element different from a semiconductor switching element 46a, for example, as a relay switching element.

[0058] The switching element 36a may comprise an intrinsic diode 42a, which is Figure 2 is illustrated schematically. The intrinsic diode 42a can be provided to allow a current to pass through in the opposite direction to the charging direction 40a.

[0059] The switch 26a preferably has at least one unidirectional element 38a. The unidirectional element 38a is a rectifying element. The unidirectional element 38a is designed as a diode. The unidirectional element 38a is connected in series with the switching element 36a. The unidirectional element 38a is connected downstream of the switching element 36a along the charging direction 40a. The unidirectional element 38a is provided to block the current counter to the charging direction 40a. The unidirectional element 38a is provided to allow the excitation current to pass along the charging direction 40a.

[0060] The switch 26a is connected between the power supply unit 18a and the induction coil 22a. The induction coil 22a can be charged by closing the switch 26a, in particular the switching element 36a.

[0061] The control unit 90a is provided for controlling the switch 26a, in particular the switching element 36a. The control unit 90a is provided for controlling the charging, in particular the jump signal. The induction hob device 10a has at least one, in particular non-inverting, gate driver 44a for controlling the switch 26a, in particular the switching element 36a. The control unit 90a is provided for controlling the switch 26a, in particular the switching element 36a, by means of the gate driver 44a.

[0062] The control unit 90a is designed to close the switch 26a, in particular the switching element 36a, for the charging period before the zero crossing. The control unit 90a is designed, in particular, to open the switch 26a, in particular the switching element 36a, at the zero crossing of the main current.

[0063] The detection unit 16a has at least one throttle unit 28a for throttling the charging process. The throttle unit 28a is designed to extend the charging time at a predetermined controlled charge level of the induction coil 22a. The throttle unit 28a is designed to extend the charging time at a predetermined controlled initial current strength of the step response.

[0064] The throttle unit 28a is connected between the power supply unit 18a and the induction coil 22a. The throttle unit 28a is connected between the power supply unit 18a and the charging control switch 26a.

[0065] The choke unit 28a is provided for throttling the excitation current, in particular the step signal. The choke unit 28a has an inductance for throttling the excitation current. The inductance of the choke unit 28a has, for example, a value of 10 mH, although another value is conceivable. The predetermined charging duration, in particular the pulse duration, stored in particular on the control unit 90a, depends on the inductance of the choke unit 28a.

[0066] The choke unit 28a has at least one gyrator 30a. The choke unit 28a, in particular the gyrator 30a, has at least one resistance element 48a. The choke unit 28a, in particular the gyrator 30a, has a capacitance element 50a. The capacitance element 50a is designed as a ceramic capacitor. The choke unit 28a has at least one choke switching element 52a. The choke switching element 52a is designed as a semiconductor switching element.

[0067] The capacitance element 50a has, for example, a capacitance of 1 µF. The inductance of the choke unit 28a depends on the capacitance of the capacitance element 50a. The predetermined charging time, stored in particular on the control unit 90a, depends on the capacitance of the capacitance element 50a.

[0068] A charged current in the induction coil 22a and thus in particular the initial current of the step response, has an exponential relationship with respect to the charging time. Figure 3 shows an exemplary graph with a curve 60a of the charged current, in particular the initial current of the step response, in the induction coil 22a on an axis 62a of the charged current versus an axis 64a of the charging duration as a multiple of a time constant τ of the exponential relationship. The time constant depends on a sum of a resistance of the induction coil 22a. The time constant depends on a sum of an inductance of the induction coil 22a and the inductance of the choke unit 28a. The current of the charged current in the induction coil 22a increases with the charging duration. A slope of the charged current in the induction coil 22a decreases with the charging duration.

[0069] Figure 4shows a graph with a curve 100a of an exemplary step response on an axis 102a of the current intensity of the step response versus an axis 104a of time.

[0070] The induction coil 22a can be discharged by means of the step response. The step response is designed as a, in particular free, damped oscillation of the charged current. The step response, in particular at least the current intensity of the step response, oscillates in an oscillating circuit 94a. The oscillating circuit 94a has at least the induction coil 22a and the at least one resonant capacitance 92a, in particular the low-side resonant capacitance 92a (cf. Figure 2 ).

[0071] The detection of the positioning unit 72a is based on determining a decay constant of a damped oscillation of the step response. The control unit 90a is designed to determine the decay constant based on the current intensity of the step response (see Figure 2). The control unit 90a is provided for detecting the positioning unit 72a based on the decay constant.

[0072] The decay constant can be determined based on at least two current intensities at at least two extreme points of the step response. The decay constant can be determined based on a ratio of the current intensities at at least two immediately consecutive minima and / or maxima, in this case at a time A and a time B, of the step response (cf. Figure 4 ).

[0073] Alternatively or additionally, the decay constant can be determined based on a frequency of the step response.

[0074] The decay constant depends on the impedance, in particular the inductance and / or resistance, of the resonant circuit 94a. The decay constant is inversely proportional to the inductance of the resonant circuit 94a. The decay constant is proportional to the resistance of the resonant circuit 94a.

[0075] The Figure 5a and 5b show exemplary graphs of the step response for two different charging times, in particular for two different step signals with different pulse durations.

[0076] Figure 5a shows a curve 114a of a first step signal with a first pulse duration of 1 ms on an axis 118a of a pulse voltage of the step signal in volts over an axis 106a of time in milliseconds. Figure 5aillustrates the generation of the step response excited by the first step signal, which is described by a curve 120a, at the zero crossing of the main current, immediately after a pulse of the step signal shown in curve 114a, wherein a curve 110a describes the at least rectified main current, which assumes a value of zero at the zero crossing of the main current. The curve 110a of the at least rectified main current is output on an axis 108a of a voltage in volts over the axis 106a of time in milliseconds. A curve 112a describes a voltage of the bus capacitor 88a provided by the main current (cf. Figure 2 ), which is at least substantially completely discharged at the zero crossing. The curve 120a of the step response is plotted on an axis 124a of the current intensity in the induction coil 22a (cf. Figure 2 ) in amperes over the 106a axis of time in milliseconds.

[0077] Figure 5b shows a curve 116a of a second step signal with a second pulse duration of 2 ms. The second pulse duration of the second step signal in Figure 5b is twice as long as the first pulse duration of the first step signal in Figure 5a . A curve 122a of the step response excited by the second step signal in Figure 5b shows an initial current which is twice as large as the initial current of the step response excited by the first step signal in Figure 5a , which is particularly evident from an arrangement of the first and second pulse duration in an approximately linear range of the exponential ratio in Figure 3 is explainable.

[0078] A preferred pulse duration of the step signal, in particular a preferred charging duration, is arranged in an approximately linear range of the exponential relationship. The charged current, in particular an initial current of the step response, can have an approximately linear relationship to the charging duration, in particular to the pulse duration of the step signal.

[0079] The detection unit 16a has at least one high-pass filter 32a for determining the step response. Figure 2 shows the high-pass filter 32a. The high-pass filter 32a is preferably provided for determining a capacitance voltage at the at least one resonant capacitance 92a, in particular at the low-side resonant capacitance 92a, for determining the current of the step response.

[0080] The high-pass filter 32a is provided to provide a measurement signal correlated with the step signal based on the determined capacitance voltage. The control unit 90a is provided to determine the step response based on the measurement signal of the high-pass filter 32a. The control unit 90a is provided to detect the positioning unit 72a based on the measurement signal of the high-pass filter 32a.

[0081] Alternatively or additionally, it is conceivable that the detection unit 16a has at least one other measuring unit known to the person skilled in the art for determining the current intensity of the step response.

[0082] The Figures 6a and 6b illustrate a dependence of the step response on the presence, in particular on the degree of coverage, of the installation unit 72a above the induction coil 22a under the same initial conditions, in particular an identical charging time, an identical throttle unit 28a, and the like.

[0083] Figure 6ashows, by way of example, a curve 130a of the step response in the absence of the mounting unit 72a above the induction coil 22a, in particular at a coverage of 0%, on an axis 126a of a capacitance voltage in volts measured by the high-pass filter 32a versus an axis 128a of a time in 50 µs. The high-pass filter 32a filters the step signal, in particular due to a low frequency of the step signal, wherein the step signal is not measured, in particular, by the high-pass filter 32a.

[0084] Figure 6b shows, by way of example, a curve 132a of the step response when the mounting unit 72a is located above the induction coil 22a, in particular at a coverage level of 100%.

[0085] The damping of the step response increases with the coverage. The decay constant of the step response increases with the coverage.

[0086] The detection unit 16a has at least one relay 34a for short-circuit bridging of at least part of the inverter 24a, in particular the inverter switch 54a, during the determination of the step response. Figure 2 shows relay 34a for short-circuit bridging. Relay 34a can bridge inverter switch 54a while charging the induction coil. Relay 34a can bridge inverter switch 54a in a detection state. Relay 34a bridges low-side inverter switch 54a at least during the step response determination.

[0087] Relay 34a is connected in parallel with inverter switch 54a. Relay 34a is connected in parallel with at least one snubber 96a.

[0088] The control unit 90a is provided for controlling the relay 34a. In a closed state, the relay 34a is provided for short-circuit bridging of at least part of the inverter 24a, in particular the inverter switch 54a.

[0089] Relay 34a provides reduced damping of the step response compared to inverter switch 54a.

[0090] Figure 7a shows data points 138a of the inductance of the resonant circuit 94a (cf. Figure 2 ) on an axis 134a of the inductance in Henry for the short-circuit bridging by means of the relay 34a over an axis 136a of the resistance of the resonant circuit 94a in Ohms during detection for a coverage level of 0% to 100%. Figure 7bshows data points 140a of the inductance of a resonant circuit (not shown) free of short-circuit bypass, specifically with inverter switch 54a, on the inductance axis 134a in Henrys versus the resonant circuit resistance axis 136a in ohms during detection for coverage levels from 0% to 100%. The resonant circuit without the short-circuit bypass by relay 34a exhibits an offset in the resonant circuit resistance.

[0091] Figure 8 shows a flowchart for a method for operating the induction hob device 10a, wherein the one installation unit 72a above the induction unit 12a can be recognized based on the step response generated at the zero crossing of the main current.

[0092] The method includes a charging step 200a in which the induction coil 22a is charged by means of the jump signal.

[0093] The method includes a discharge step 202a in which the induction coil 22a is discharged. In the discharge step 202a, the induction coil 22a is discharged using the step response, which comprises the damped free oscillation of the current intensity. The step response is generated in the discharge step 202a at the zero crossing of the main current. The step response is determined in the discharge step 202a.

[0094] The method includes an evaluation step 204a in which the step response is evaluated. In evaluation step 204, the decay constant of the step response is determined. The presence of the positioning unit 72a above the induction unit 12a is detected in evaluation step 204a based on the decay constant.

[0095] Of the multiple objects present, only one is provided with a reference symbol in the figures.

[0096] In Figure 9A further embodiment of the invention is shown. The following descriptions are essentially limited to the differences between the embodiments, with reference to the description of the embodiment of the Figures 1 to 8 To distinguish the embodiments, the letter a in the reference numerals of the embodiment in the Figures 1 to 8 by the letter b in the reference numerals of the embodiment of the Figure 9 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 embodiment of the Figure 9 be referred to.

[0097] Figure 9 shows a circuit diagram of an induction hob device 10b with a Figure 2shown embodiment, an alternatively configured choke unit 28b. The choke unit 28b has a choke coil 56b. The inductance of the choke unit 28b is provided solely by the choke coil 56b. The choke unit 28b has a freewheeling diode 58b. The freewheeling diode 58b is connected in parallel with the choke coil 56b. The choke unit 28b is formed by the choke coil 56b and the freewheeling diode 58b. Reference symbol

[0098] 10 Induction cooktop device 12 Induction unit 14 Main power supply unit 16 Detection unit 18 Power supply unit 20 Circuit 22 Induction coil 24 Inverter 26 Switch 28 Choke unit 30 Gyrator 32 High-pass filter 34 Relay 36 Switching element 38 Unidirectional element 40 Charging direction 42 Intrinsic diode 44 Gate driver 46 Semiconductor switching element 48 Resistive element 50 Capacitance element 52 Choke switching element 54 Inverter switch 56 Choke coil 58 Freewheeling diode 60 Curve 62 Axis 64 Axis 70 Induction cooktop 72 Mounting unit 74 Cookware 76 Mounting plate 78 Operator interface 80 Control element 82 Transfer zone 84 Filter unit 86 Rectifier 88 Bus capacitor 90 Control unit 92 Resonant capacitance 94 Resonant circuit 96 Snubber 98 Connection 100 Curve 102 Axis 104 Axis 106 Axis 108 Axis 110 Curve 112 Curve 114 Curve 116 Curve 118 Axis 120 Curve 122 Curve 124 Axis 126 Axis 128 Axis 130 Curve 132 Curve 134 Axis 136 Axis 138 Data points 140 Data points 200 Charge step 202 Discharge step204Evaluation step

Claims

1. Induction hob device (10a; 10b) with at least one induction unit (12a; 12b) which is operable by means of a main current of a main power supply unit (14a; 14b), and with at least one detection unit (16a; 16b) for detecting a mounting unit (72a) above the induction unit (12a; 12b), characterized in that the detection is based on a step response generated at a zero crossing of the main current.

2. Induction hob device (10a; 10b) according to claim 1, characterized in that the detection unit (16a; 16b) has a power supply unit (18a; 18b) for providing a step signal for exciting the step response.

3. Induction hob device (10a; 10b) according to claim 1 or 2, characterized in that the excitation of the step response can be generated freely by an inverter (24a; 24b).

4. Induction hob device (10a; 10b) according to one of the preceding claims, characterized in thatthe induction unit (12a; 12b) has at least one induction coil (22a; 22b), wherein a step signal for exciting the step response can be generated by charging the induction coil (22a; 22b) with current.

5. Induction hob device (10a; 10b) according to claim 4, characterized in that the detection unit (16a; 16b) has at least one, in particular unidirectional, switch (26a; 26b) for controlling the charging.

6. Induction hob device (10a; 10b) according to claim 4 or 5, characterized in that the detection unit (16a; 16b) has at least one throttle unit (28a; 28b) for throttling the charging.

7. Induction hob device (10a) according to claim 6, characterized in that the throttle unit (28a) has at least one gyrator (30a).

8. Induction hob device (10a; 10b) according to one of the preceding claims, characterized in thatthe detection of the positioning unit (72a) is based on a determination of a decay constant of a damped oscillation of the step response.

9. Induction hob device (10a; 10b) according to one of the preceding claims, characterized in that the detection unit (16a; 16b) has at least one high-pass filter (32a; 32b) for determining the step response.

10. Induction hob device (10a; 10b) according to one of the preceding claims, characterized by an inverter (24a; 24b), wherein the detection unit (16a; 16b) has at least one relay (34a; 34b) for short-circuit bridging of at least part of the inverter (24a; 24b) during a determination of the step response.

11. Induction hob (70a) with an induction hob device (10a; 10b) according to one of the preceding claims.

12. Method for operating an induction hob device (10a; 10b), in particular according to one of claims 1 to 10, with an induction unit (12a; 12b) operable by means of a main current, characterized in that a positioning unit (72a) above the induction unit (12a; 12b) based on a step response generated at a zero crossing of the main current is recognizable.

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