EP2506666A1 - Cooking device - Google Patents

Abstract

The device has a controlling unit designed such that two heating frequency units are operated together in a time period (t) that is divided into two time intervals (Ta, Tb). The controlling unit is designed to select a control type for each time interval, from a catalog of control types, and to determine frequencies (f1a, f2a, f1b, f2b) of control signals of the heating frequency units based on the selected control type under temporal stabilization of average output powers (P1, P2) of the frequency units. The control unit adjusts the output powers to selected target powers (Pobj1, Pobj2). An independent claim is also included for a method for operating a cooking device.

Description

The invention is based on a cooking device device according to the preamble of claim 1.

The publication EP 1 951 003 A1 discloses an induction hob having at least two heating frequency units operated according to a particular method to at least substantially avoid intermodulation noise. According to this method, both heating-frequency units are operated at an identical and fixed first frequency in a first time interval. In a second time interval, a heating frequency unit is switched off, while the other heating frequency unit is operated at a fixed second frequency. The two frequencies and the relative lengths of the two time intervals are adjusted so that an average output power of each heating frequency unit corresponds to an operator selected heating power. At the same time flicker is minimized.

The object of the invention is, in particular, to provide a cooking appliance device of the generic type which enables an advantageously flexible setting of an average output power and simple scalability to a multiplicity of heating frequency units. The object is achieved by the features of claim 1 and the method claim 9, while advantageous embodiments and refinements of the invention can be taken from the dependent claims.

The invention is based on a cooking device device with at least one first and at least one second heating frequency unit and with at least one control unit which is provided to operate the at least two heating frequency units together periodically with a period duration and to divide the period into at least two time intervals.

It is proposed that the control unit is provided for selecting a control type from a catalog of control types for each of the at least two time intervals. The cooking device device is preferably designed as a hob device and particularly advantageously as an induction hob device. By "provided" is intended to be understood in particular specially programmed and / or designed and / or equipped. By the fact that the control unit is intended to "subdivide the period into at least two time intervals", should be understood in particular that the control unit defines at least two overlap-free time intervals in at least one operating state within the period. Preferably, a sum of the lengths of the at least two time intervals is equal to the period duration. A "heating frequency unit" should in particular be understood to mean an electrical unit which generates an oscillating electrical current, preferably with a frequency of at least 15 kHz, in particular of at least 17 kHz and advantageously of at least 20 kHz, for operation of at least one heating unit. A "heating unit" is to be understood in particular as meaning a unit which is intended to convert electrical energy into heat, at least to a large extent, and thus in particular to heat a food to be cooked. In particular, the heating unit comprises a radiant heater, a resistance heater and / or preferably an induction heater, which is intended to convert electrical energy indirectly via induced eddy currents into heat. The heating frequency unit comprises in particular at least one inverter, which preferably comprises two switching units. A "switching unit" is to be understood in particular as meaning a unit which is intended to interrupt a conduction path comprising at least part of the switching unit. Preferably, the switching unit is a bidirectional unipolar switch which in particular allows a current flow through the switch along the conduction path in both directions and in particular short-circuits an electrical voltage in at least one polarity direction. Preferably, the inverter comprises at least two bipolar transistors with insulated gate electrode and particularly advantageously at least one damping capacitor. Under a "conduction path" in particular an electrically conductive Headpiece between two points to be understood. The term "electrically conductive" is to be understood in particular with a specific electrical resistance of at most 10 ^-4 Ωm, in particular of at most 10 ^-5 Ωm, advantageously of at most 10 ^-6 Ωm and particularly advantageously of not more than 10 ^-7 Ωm at 20 ° C.

A "control unit" is to be understood in particular as meaning an electronic unit which is preferably at least partially integrated in a control and / or regulating unit of a cooking appliance, in particular an induction hob, and which preferably has an arithmetic unit and in particular in addition to the arithmetic unit a storage unit with a stored therein Control program includes. Preferably, the control unit is at least provided to control and / or regulate the heating frequency units by means of control signals and preferably electrical control signals. A "control signal" should be understood in particular to mean a signal which, in particular in at least one operating state, triggers a switching operation of a heating frequency unit, in particular also indirectly. An "electrical control signal" is to be understood in particular to mean a control signal having an electrical potential of at most 30 V, preferably of at most 20 V, particularly advantageously of at most 10 V and in particular of at least 5 V relative to a reference potential. Preferably, the control signal has a periodicity at least at times, in particular with a period of at most 1 ms, in particular of at most 0.1 ms and advantageously of at most 0.05 ms. Particularly advantageously, the control signal is at least substantially a rectangular signal, which in particular has two discrete values, preferably a switch-on value and a switch-off value. Preferably, each of the two values corresponds to a switching position of the heating frequency units and in particular their inverter. A "frequency" of a heating frequency unit is to be understood in particular as the frequency of the control signal controlling the heating frequency unit.

By the fact that the control unit is intended to select "one type of control from a catalog of control types" for each of the at least two time intervals, it should be understood in particular that the control unit is intended to be active and dependent on given conditions for the at least two time intervals Select combination of control types. The boundary conditions may be any boundary conditions that appear appropriate to a person skilled in the art, but preferably selected output powers for the at least two heating frequency units, curves of the power frequency curves for a given system of cooking utensils and heating unit, a specification for minimization by Flicker and / or by a requirement to minimize fluctuation in the output of heating units. By "flicker" is meant in particular a subjective impression of an instability of a visual perception, which is caused in particular by a light stimulus whose luminance and / or spectral distribution varies with time. In particular, flicker can be caused by a voltage drop of a mains voltage.

A "type of control" is to be understood in particular as a type of control of the at least two heating frequency units by the control unit in a time interval, two different types of control being delineated, in particular, by the two types of control using a different number of operated heating frequency units and / or a different number of used Have frequencies and / or differ by at least one type of calculation and preferably a frequency-independent calculation, by means of which at least one frequency used the type of control results from another frequency used the type of control. A "used frequency" of a type of control should be understood to mean, in particular, a numerical value of a frequency used in the type of control, whereby zero should also be regarded as a numerical value. A "type of calculation" is understood to mean, in particular, a type of calculation by means of at least one mathematical operator, the type of calculation is defined exclusively by the at least one mathematical operator and in particular its arrangement to further mathematical operators. In particular, numerical values of constants should be irrelevant when differentiating between two types of calculation. The type of calculation is preferably a "simple calculation type", which in particular has exactly one mathematical operator, in particular an addition operator. Preferably, the calculation type is an addition of a frequency-independent constant, an exact numerical value of the constant being irrelevant. By the fact that a heating frequency unit is "operated" should be understood in particular that the frequency of the heating frequency unit in the relevant time interval is different from zero. Preferably, each type of control allows a common operation of the at least two heating frequency units, at least largely avoiding intermodulation noise. By "intermodulation noise" is meant, in particular, sounds whose frequency spectra have at least one non-zero component with a frequency of less than 18 kHz, in particular less than 17 kHz, preferably less than 16 kHz and particularly advantageously less than 15 kHz. The fact that a type of control permits a common operation of the at least two heating frequency units "with at least largely avoiding intermodulation noises" is to be understood in particular as meaning that in a joint operation of the at least two heating frequency units according to the type of control intermodulation noises at a distance of 1 m from the cooking appliance apparatus Have a maximum sound pressure level of 20 dB, in particular of at most 10 dB, preferably of at most 5 dB and particularly advantageously of at most 0 dB. Preferably, the intermodulation sounds are then inaudible by an average hearing operator.

A "catalog of control types" is to be understood in particular as a collection of different types of control. As control modes are all, one of the expert appear appropriate sense control types in question. Preferably belongs to the catalog of control types a type of control all heating frequency units are operated at the same non-zero frequency. Preferably belongs to the catalog of control types a type of control in which all heating frequency units are turned off. Preferably belong to the catalog of control types control types in which at least one heating frequency unit is turned off and the other heating frequency units are operated at the same frequency. Preferably, the catalog of control types control types in which all heating frequency units are operated and a difference between frequencies of any two heating frequency units zero or at least 15 kHz, in particular at least 16 kHz, preferably at least 17 kHz and more preferably at least 18 kHz. Preferably, the catalog of control types control types in which at least one Heizfrequenzeinheit is turned off and a difference between frequencies of any two operated Heizfrequenzeinheiten zero or at least 15 kHz, in particular at least 16 kHz, preferably at least 17 kHz and more preferably at least 18 kHz. The fact that a heating frequency unit is "switched off" in a time interval should in particular be understood to mean that the heating frequency unit has at least substantially a negligibly low output power in the relevant time interval. A "at least substantially negligibly low output power in the relevant time interval" is to be understood in particular as an output power which is at most 50 W, in particular at most 25 W, preferably at most 10 W and particularly advantageously 0 W and / or during the time interval exclusively during a period of time is delivered, which corresponds to at most 50%, in particular at most 25%, preferably at most 15% and most preferably at most 10% of a length of the time interval. An "output power" of one of the at least two heating-frequency units should in particular be understood to mean a power which is supplied by the heating-frequency unit in at least one heating operating state.

By means of such an embodiment, an advantageously flexible setting of an average output power can be achieved. Furthermore, a simple scalability to a variety of heating frequency units can be made possible.

In a preferred embodiment of the invention, it is proposed that the control unit is provided to select those types of control for the at least two time intervals, the operation of the at least two Heizfrequenzeinheiten with minimal fluctuations in total output power of the at least two Heizfrequenzeinheiten and / or a respective output of the at least enable two heating frequency units. A "total output power" of the at least two heating frequency units should in particular be understood as meaning a sum of the output powers of the at least two heating frequency units. By the fact that the control unit is intended to select those types of control which allow operation of the at least two heating frequency units "with the lowest possible fluctuations of a respective output power" should be understood in particular that it is intended to select those types of control in which a maximum maximum fluctuation the output power of the at least two Heizfrequenzeinheiten is minimal. Preferably, the control unit is provided to consider those types of control for the at least two time intervals for which the total output power is at least substantially constant and to select from these types of control those which allow operation of at least two Heizfrequenzeinheiten with the lowest possible fluctuations of a respective output power. By the fact that a "total output power is at least largely constant" should be understood in particular that the total output power in at least one operating state has a relative temporal fluctuation, which is smaller than a legal requirements and / or standards, in particular by the standard DIN EN 61000- 3-3 is the specified flicker limit. As a result, an ease of use can be increased advantageously, since an at least largely uniform power output achieved and flicker can be minimized.

In a particularly preferred embodiment of the invention, it is proposed that the control unit be provided to determine, for at least two time intervals, frequencies of control signals of the at least two heating frequency units under at least substantially constant temporal stabilization of a total output power of the at least two heating frequency units according to the selected control modes. By the fact that the control unit is intended to determine the frequencies of the control signals "at least substantially constant temporal constant total output", should be understood in particular that the control unit determines the frequencies of the heating frequency units in at least one operating state such that the total output power a relative temporal Fluctuation which is smaller than a flicker limit specified by legal requirements and / or standards, in particular by the standard DIN EN 61000-3-3. As a result, flicker can be advantageously minimized.

It is also proposed that the control unit is provided to adapt average output powers of the at least two heating frequency units to selected desired powers. A "mean output power" is to be understood in particular a time-averaged output power. In this case, a relative deviation of the set by the control unit average output power of the target power should be at most 10%, preferably at most 5% and more preferably at most 1%. As a result, a high level of operating comfort can be achieved. Preferably, the average output power of one of the at least two heating frequency units is always less than or equal to the desired power of the corresponding heating frequency unit. As a result, unsafe operating conditions can be avoided.

Advantageously, the control unit is provided to make an adjustment of the average output power of the at least two heating frequency units by adjusting the at least two time intervals, in particular while keeping constant the previously determined frequencies. As a result, an advantageously high ease of use can be achieved, since on the one hand minimizes flicker and on the other hand, a desired power adjusted average output power can be provided.

In a further embodiment of the invention, it is proposed that the control unit is provided to control and / or regulate the at least two heating frequency units in each case by means of a control signal and to adjust a duty cycle of at least one of the control signals in at least one operating state. In particular, a ratio of a time duration in which the control signal assumes the switch-on value within a period duration to the period duration of the control signal is to be understood as a "duty cycle". Preferably, at a fixed frequency of one of the heating frequency units by changing the duty cycle, an output of the heating frequency unit can be changed. By the fact that the control unit is intended to "adjust a duty cycle of at least one of the control signals", it should be understood in particular that the control unit is intended to change the duty cycle of at least one of the control signals, thereby changing a fixed output power Frequency of a heating frequency unit. In this way, flexibility in setting the mean output powers of the at least two heating frequency units can be further advantageously increased.

Furthermore, it is proposed that the control unit be provided to subdivide the period into a number of time intervals corresponding to a number of heating frequency units to be operated simultaneously. The time intervals preferably follow one another directly so that a sum of lengths corresponds to the time intervals of the period. As a result, the control method according to the invention for a cooking device device with more than two heating frequency units and in particular to a cooking appliance device for a matrix hob can be scaled. A "matrix hob" is to be understood in particular a hob, are arranged in the heating units in a regular grid under a hob plate, and a heatable by means of the heating units of the hob plate preferably at least 60%, in particular at least 70%, advantageously at least 80% and particularly advantageously comprises at least 90% of a total area of the hob plate. In particular, the matrix cooktop comprises at least 10, in particular at least 20, advantageously at least 30 and particularly advantageously at least 40 heating units.

Advantageously, the control unit is provided to determine power frequency curves for different duty cycles of a control signal of the at least two heating frequency units. A "power frequency curve" is to be understood, in particular, as a functional relationship that is specific for each combination of a cooking utensil and a heating unit and dependent on the duty factor, which unambiguously assigns an output power to each frequency for a given duty cycle. By the fact that the control unit is intended to "determine power frequency curves for different duty cycles of a control signal of the at least two heating frequency units" should be understood in particular that the control unit operates in at least one operating state of the at least two Heizfrequenzeinheiten with different frequencies for a short time and for each of these frequencies the output power of the at least one heating frequency unit is read from a measuring unit. In this way, an advantageously precise heating operation can be made possible.

Furthermore, a method is proposed with a cooking device device having at least one first and at least one second heating frequency unit, in particular according to one of the preceding claims, in which the heating frequency units are operated together periodically with a period duration and the period duration is subdivided into at least two time intervals, wherein for each the at least two time intervals for minimizing intermodulation noises one control type is selected from a catalog of control types. As a result, an advantageously flexible setting of an average output power and a simple scalability to a plurality of heating frequency units can be made possible.

Furthermore, a cooking appliance, in particular a hob, proposed with a Gargerätevorrichtung invention. Preferably, the hob is an induction hob. The cooktop can also be a matrix cooktop, and more preferably a matrix induction cooktop. A "matrix induction hob" is to be understood, in particular, as a matrix hob which has at least one heating unit comprising an induction heater.

Further advantages emerge from the following description of the drawing. In the drawing, two embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

ein Induktionskochfeld mit einer erfindungsgemäßen Gargerätevorrichtung mit zwei Heizfrequenzeinheiten,

Fig. 2

ein beispielhaftes, nicht maßstabsgetreues Steuersignal einer der zwei Heizfrequenzeinheiten,

Fig. 3a

beispielhafte, nicht maßstabsgetreue Leistungs-Frequenz-Kurven für die zwei Heizfrequenzeinheiten gemäß einer ersten Kombination aus Steuerungsarten,

Fig. 3b

je eine beispielhafte, nicht maßstabsgetreue Leistungs-Zeit-Kurve für die zwei Heizfrequenzeinheiten gemäß der ersten Kombination der Steuerungsarten aus Fig. 3a,

Fig. 3c

beispielhafte, nicht maßstabsgetreue Leistungs-Frequenz-Kurven einer der zwei Heizfrequenzeinheiten bei unterschiedlichen Tastgraden eines Steuersignals,

Fig. 3d

beispielhafte, nicht maßstabsgetreue Gesamtleistungs-Zeit-Kurven gemäß der ersten Kombination der Steuerungsarten aus Fig. 3a,

Fig.4a

beispielhafte, nicht maßstabsgetreue Leistungs-Frequenz-Kurven für die zwei Heizfrequenzeinheiten gemäß einer zweiten Kombination aus Steuerungsarten,

Fig. 4b

je eine beispielhafte, nicht maßstabsgetreue Leistungs-Zeit-Kurve für die zwei Heizfrequenzeinheiten gemäß der zweiten Kombination der Steuerungsarten aus Fig. 4a und

Fig. 5

beispielhafte, nicht maßstabsgetreue Leistungs-Zeit-Kurven für N gleichzeitig betriebene Heizfrequenzeinheiten einer weiteren erfindungsgemäßen Gargerätevorrichtung.

Show it:

Fig. 1

an induction hob with a cooking appliance device according to the invention with two heating frequency units,

Fig. 2

an exemplary, not to scale, control signal of one of the two heating frequency units,

Fig. 3a

exemplary, not to scale true power frequency curves for the two heating frequency units according to a first combination of control types,

Fig. 3b

an exemplary, not to scale true power-time curve for the two heating frequency units according to the first combination of control types Fig. 3a .

Fig. 3c

exemplary, not to scale power frequency curves of one of the two heating frequency units at different duty cycles of a control signal,

Fig. 3d

exemplary, non-to-scale total power-time curves according to the first combination of control types Fig. 3a .

4a

exemplary, not to scale true power frequency curves for the two heating frequency units according to a second combination of control types,

Fig. 4b

an exemplary, not to scale true power-time curve for the two Heizfrequenzeinheiten according to the second combination of control types Fig. 4a and

Fig. 5

exemplary, not to scale power-time curves for N simultaneously operated Heizfrequenzeinheiten another cooking appliance device according to the invention.

FIG. 1 shows a trained as induction hob 16a cooking appliance. The induction hob 16a comprises a hob plate 18a, in particular of a glass ceramic, on which two heating zones 20a, 22a are marked in a known manner. The hob plate 18a is horizontally disposed in an operative state of the induction hob 16a and provided for setting up cooking utensils. Furthermore, touch-sensitive operating elements 26a and display elements 28a of an operating and display unit 30a of the induction hob 16a are marked in a known manner on the hob plate 18a. The induction hob 16a further comprises a cooking appliance device having a first and a second heating frequency unit 10a, 12a arranged below the hob plate 18a and with a control unit 14a arranged below the hob plate 18a. In FIG. 1 are components which are arranged below the hob plate 18a, drawn schematically and dashed, with functional relationships are indicated by arrows. The control unit 14a is integrated in a control and regulation unit 32a of the induction hob 16a. An induction heating unit associated with and located below the heating zone 20a is energized by the first heating frequency unit 10a. An induction heating unit associated with and located below the heating zone 22a is energized by the second heating frequency unit 12a. An operator can select a heating stage for each of the heating zones 20a, 22a by means of the operating and display unit 30a, which results in a desired output P _obj1 , P _obj2 for the two heating frequency units 10a, 12a. The control unit 14a is to provided to _adapt a respective average output power P _ave1 , P _{ave2 of} the heating frequency units 10a, 12a to the desired power P _obj1 , P _obj2 while largely avoiding Intermodulationsgeräuschen so that the selected heating levels of the heating zones 20a, 22a can be achieved. In addition, the control unit 14a is provided to minimize a total output power difference F. The total output power difference F is a maximum difference between two total output powers P ₁ + P _{2 of} the two heating frequency units 10a, 12a at two different times t ₁ and t ₂ : $$\mathrm{F}\mathrm{=}\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{1}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{1}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{2}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{2}}\right)\right|\mathrm{,}$$

Here, P ₁ (t) designates the output power of the first heating frequency unit 10 a at time t and P ₂ (t) the output power of the second heating frequency unit 12 a at time t. The control unit 14a controls the first heating frequency unit 10a by means of a control signal V ₁ (t) and the second heating frequency unit 12a by means of a control signal V ₂ (t).

FIG. 2 shows by way of example a not to scale control signal V ₁ (t) of the first heating frequency unit 10a in a Cartesian coordinate system. An ordinate axis 36 has a control voltage V ₁ and an abscissa axis 38 a time t. The control signal V ₁ (t) is during a first time interval T _A a period T a square wave signal with a switch-V ₀ , a switch-off of 0 volts and a frequency of f _1A . The switch-on value V ₀ is held during a switch-on time t _0A . In the first time interval T _A is a period of the square wave _signal T _0A . During a period of (T _0A -t _0A ), the turn-off _value is held. The frequency f _{1A of} the control signal V ₁ (t) is calculated from a reciprocal of the period T _0A . The frequency f _1A is usually between 20 kHz and 100 kHz. A duty cycle D _{1A of} the control signal V ₁ (t) in the first time interval T _{A is} calculated from a quotient of the switch-on time t _0A divided by the period T _0A . The control signal V ₁ (t) is also on during a second time interval T _{B of} a period T Square-wave signal with the switch-on value V ₀ and the switch-off value of 0 Volt. However, in the second time interval T _B , one frequency is f _1B . The switch-on _value V ₀ is held during a switch-on time t _0B . In the second time interval T _B is a period of the square wave _signal T _0B . During a period of (T _0B -t _0B ), the turn-off _value is held. The frequency f _{1B of} the control signal V ₁ (t) is calculated from a reciprocal of the period T _0B . The frequency f _1B is usually between 20 kHz and 100 kHz. A duty cycle D _{1B of} the control signal V ₁ (t) in the second time interval T _{B is} calculated from a quotient of the turn-on time t _0B divided by the period T _0B . A time x separates the first time interval T _A and the second time interval T _B. After the period T has elapsed, the control signal V ₁ (t) is repeated. Following a course of V ₁ (t), according to a periodic change of the turn-on value V ₀ and the turn-off value, a first of two switching units of the first heating frequency unit 10a is periodically switched. A second switching unit of the first heating frequency unit 10a is periodically switched in an analogous but time-shifted manner so that a high-frequency alternating current results in an operation of the induction heating unit assigned to the heating zone 20a.

For a joint operation of the two Heizfrequenzeinheiten 10a, 12a are certain conditions on the frequencies f _1X, f _2X of the control signals V ₁ (t), V ₂ (t) of the Heizfrequenzeinheiten 10a to provide 12a perceived by a user as disturbing intermodulation noise to minimize. The index "X" stands here for the letters "A" and "B", which designate the time intervals T _A and T _B. In the case of two simultaneously operated Heizfrequenzeinheiten 10a, 12a following substantially interference-free control modes (f _1X, f _2X) are conceivable for a time interval T _X: (1) Both Heizfrequenzeinheiten 10a, 12a are in the time interval T _X with the same non-zero frequency f _1X , f _2X operated. (2) One of the two heating frequency units 10a, 12a is turned off in the time interval T _X. (3) Both heating-frequency units 10a, 12a are switched off in the time interval T _X. (4) The two heating frequency units 10a, 12a are operated in the time interval T _X with a frequency difference k, wherein the frequency difference k is at least 15 kHz. It is the task of the control unit 14a, from this catalog of control _types (f _1X , f _2X ) for each of the two time intervals T _A and T _B select a suitable control mode (f _1X , f _2X ) and the Heizfrequenzeinheiten 10a, 12a according to this type of control (f _1X , f _2X ), so that the mean output power P _ave1 , P _ave2 of each heating frequency unit 10a, 12a corresponds to their desired power P _obj1 , P _obj2 .

In the event that an operator selects simultaneous operation of both heating-frequency units 10a, 12a by means of the operating and display unit 30a, the control unit 14a first checks whether cooking equipment suitable for inductive heating is placed on the heating zones 20a, 22a of the hob plate 18a. If this is the case, the control unit 14 _j in a next step, for different duty cycles d power-frequency curve P ₁ (f, d _j), P ₂ (f, d _j) of a given combination of induction heating and cooking containers. For this purpose, the control unit 14a changes stepwise a frequency f of a control signal V ₁ (t), V ₂ (t) from a maximum frequency f _max to a respective minimum frequency f _min1 , f _min2 for a fixed duty cycle d _j , operates the respective heating frequency unit 10 a, 12a briefly with the set frequency f and reads the output power P ₁ , P _{2 of} the relevant heating frequency unit 10a, 12a from a measuring unit of Gargerätevorrichtung. The control unit 14a performs this determination for duty cycles _dj = 50%, 40%, 30%, 20% and 10%. By way of example, this results in the heating frequency unit 10a, the in Figure 3c shown power frequency curves P ₁ (f, d _j ) for different duty cycle d _j .

und $$\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\right|\mathrm{\le }\mathrm{G},$$

wobei t_A bzw. t_B einen beliebigen Zeitpunkt innerhalb des Zeitintervalls T_A bzw. T_B kennzeichnet. Hierbei gelten zusätzliche Grenzwerte für die Frequenzen f_1A, f_2A, f_1B, f_2B. Zum einen existiert jeweils die kurvenspezifische Mindestfrequenz f_min1 und f_min2 und damit eine maximal erreichbare Ausgangsleistung P₁, P₂ für jede Heizfrequenzeinheit 10a, 12a. Des Weiteren existiert die gemeinsame durch elektronische Restriktionen gegebene Höchstfrequenz f_max und damit eine in einem kontinuierlichen Betrieb minimal erreichbare Ausgangsleistung P₁, P₂ für jede Heizfrequenzeinheit 10a, 12a. Der gültige Frequenzbereich ist also folgendermaßen eingeschränkt: $${\mathrm{f}}_{\min \mathrm{1}\mathrm{/}\mathrm{2}}\mathrm{\le }{\mathrm{f}}_{\mathrm{1}\mathrm{A}}\mathrm{,}{\mathrm{f}}_{\mathrm{2}\mathrm{A}}\mathrm{,}{\mathrm{f}}_{\mathrm{1}\mathrm{B}}\mathrm{,}{\mathrm{f}}_{\mathrm{2}\mathrm{B}}\mathrm{\le }{\mathrm{f}}_{\max }\mathrm{.}$$

Since two heating-frequency units 10a, 12a are to be operated simultaneously, the period T is to be subdivided into the two time intervals T _A and T _B , the lengths of which are determined in a later step. First, the control unit 14a selects a catalog of types of control (f _1X, f _2X) for each of the two time intervals T _A, T _B, a control mode (f _1X, f _2X), so that with an appropriate choice of the frequencies f _{1 A,} f _2A , f _1B , f _2B and of duty D _1A , D _2A , D _1B , D _2B as small variations in the total output power P ₁ + P _{2 of} the two Heizfrequenzeinheiten 10 a, 12 a and a respective output power P ₁ , P _{2 of} the at least two Heizfrequenzeinheiten 10th , 12 occur. The control unit 14a is considered For this purpose, all types of control (f _1X , f _2X ) for which the total output power difference F at the transition from the first time interval T _A to the second time interval T _B with a corresponding choice of frequencies f _1A , f _2A , f _1B , f _2B and duty D _1A , D _2A , D _1B , D _{2B is} smaller than a flicker limit G determined by the standard DIN EN 61000-3-3: $$\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\right|\mathrm{\le }\mathrm{G}$$

and $$\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\right|\mathrm{\le }\mathrm{G}.$$

where t _A and t _B a desired time within the time interval T _A and T _B indicates. In this case, additional limit values apply for the frequencies f _1A , f _2A , f _1B , f _2B . On the one hand, there exists in each case the curve-specific minimum frequency f _min1 and f _min2 and thus a maximum achievable output power P ₁ , P ₂ for each heating frequency unit 10a, 12a. Furthermore, there is the common maximum frequency f _max given by electronic restrictions and thus a minimum achievable output power P ₁ , P ₂ for each heating frequency unit 10a, 12a in a continuous operation. The valid frequency range is thus restricted as follows: $${\mathrm{f}}_{\min \mathrm{1}\mathrm{/}\mathrm{2}}\mathrm{\le }{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{1}\mathrm{A}}\mathrm{.}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{2}\mathrm{A}}\mathrm{.}{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{1}\mathrm{B}}\mathrm{.}{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{2}\mathrm{B}}\mathrm{\le }{\mathrm{f}}_{\mathrm{Max}}\mathrm{,}$$

und $${\mathrm{P}}_{\mathrm{ave}\mathrm{2}}\mathrm{=}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\mathrm{.}$$

From the control types considered (f _1X , f _2X ), the control unit 14a for the common operation of the heating-frequency units 10a, 12a finally selects the type of control (f _1X , f _2X ) for which a maximum fluctuation of the output power P ₁ , P ₂ of each Heating frequency unit 10a, 12a is minimal. Subsequently, the control unit 14a determines the lengths of the time intervals T _A and T _B such that the average output power of each heating frequency unit 10a, 12a corresponds to the respective desired power P _obj1 , P _obj2 : $${\mathrm{P}}_{\mathrm{ave}\mathrm{1}}\mathrm{=}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}$$

and $${\mathrm{P}}_{\mathrm{ave}\mathrm{2}}\mathrm{=}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\mathrm{,}$$

The selection process performed by the control unit 14a will be explained below with reference to a case example. Assuming the control unit 14a have determined predetermined combinations P _obj1 , P _obj2 two combinations of control _types (f _1X , f _2X ), which in a transition from the first time interval T _A to the second time interval T _B with a corresponding choice of frequencies f _1A , f _2A , f _1B , f _2B and duty cycles D _1A , D _2A , D _1B , D _{2B have} a total output power difference F which is smaller than the flicker limit value G.

For this case shows FIG. 3a in a Cartesian coordinate system, for example, two power-frequency curves P ₁ (f) and P ₂ (f) for the first combination of control _types (f _1X , f _2X ), which are not true to scale. On an ordinate axis 42, output powers P ₁ and P _{2 of} the heating frequency units 10a, 12a are plotted. On an abscissa axis 44, the frequency f is plotted. The target powers P _obj1 and P _{obj2 of} the heating frequency units 10a, 12a are set by an operator. The desired powers P _obj1 , P _{obj2 are} assigned _nominal frequencies f _obj1 , f _obj2 . Without limiting the generality, let it be assumed that the second heating frequency unit 12a has the highest _setpoint frequency f _obj2 . This is then operated by the control unit 14a in both time intervals T _A and T _B continuously with a fixed frequency f _2A = f _2B , which corresponds to the desired frequency f _obj2 . The first heating frequency unit 10a is operated by the control unit 14a in the first time interval T _A with a frequency f _1A lower by 18 kHz. Since the output power P _{1 of} the first heating frequency unit 10a at the frequency f _1A exceeds the setpoint power P _{obj1 of} the first heating frequency unit 10a, the first heating frequency unit 10a is switched off in the second time interval T _B. The control _modes used here (f _1X , f _2X ) for the time intervals T _A , T _B are therefore the following: In the first time interval T _A , the two heating frequency units 10a, 12a are operated with a frequency difference k of 18 kHz (4). In the second time interval T _B , one of the heating frequency units 10 a is switched off (2).

FIG. 3b shows in a Cartesian coordinate system by way of example two not-to-scale power-time curves P ₁ (t) and P ₂ (t) for the first combination of control types FIG. 3a , On an ordinate axis 46 are the output powers P ₁ and P _{2 of} the heating frequency units 10a, 12a applied. The time t is plotted on an abscissa axis 48. An in FIG. 3b illustrated course of the power-time curves P ₁ (t) and P ₂ (t) is in a heating operation state of the heating-frequency units 10 a, 12 a periodically through the period T. The calculation of the lengths of the time intervals T _A and T _{B of} the period T by the control unit 14 a is carried out as described above. As based on the FIG. 3b to recognize, there is a jump in the total output power P ₁ + P ₂ at the transition from the first time interval T _A to the second time interval T _B. In order for this type of control (f _1X , f _2X ) to be considered at all, the duty cycle D _{1A of} the control signal V ₁ (t) of the first heating frequency unit 10a has been lowered from 50% to 20% in the first time interval T _A.

Figure 3c shows in a Cartesian coordinate system by way of example not true to scale power frequency curves P ₁ (f, d _j ) for different duty cycles D _1A = d _j (j = 1, ..., n) of the control signal V ₁ (t) of the first Heating frequency unit 10a (see also FIG. 2 ). On an ordinate axis 50, the output power P _{1 of} the first heating frequency unit 10a is plotted. On an abscissa axis 52, the frequency f is plotted. By adapting the duty cycle D _1A , for example from 0.5 to smaller values, the control unit 14a can adjust the output power P _{1 of} the first heating frequency unit 10a. In this way, in particular a lowering of the output power P ₁ at a fixed frequency f _{1A of} the first heating frequency unit 10a can be achieved.

3d figure In two Cartesian coordinate systems, for example, shows two non-to-scale total power-time curves for the first combination of control types FIG. 3a , The sum of the output powers P ₁ + P _{2 of} the heating frequency units 10 a, 12 a is plotted on an ordinate axis 54 in each case. On an abscissa axis 56, the time t is plotted during three periods T in each case. The top of the two coordinate systems 3d figure FIG. 12 shows a case where the duty D _{1A of} the first heating frequency unit 10a has a value d ₁ . According to Figure 3c At the frequency f _1A , an output power P _{1 of} the first heating frequency unit 10a of P ₁ (f _1A , d ₁ ) is then obtained. The lower of the two coordinate systems 3d figure FIG. 15 shows a case where the duty D _{1A of} the first heating frequency unit 10a has a value d _n which is smaller than d ₁ . According to Figure 3c At the frequency f _1A , the output power P _{1 of} the first heating frequency unit 10a of P ₁ (f _1A , d _n ) is smaller than the output power P ₁ (f _1A , d ₁ ). As based on 3d figure To recognize, the output power difference F can be reduced by the choice of a smaller duty cycle D _1A . The control unit 14a uses this fact to minimize the total output power difference F below the flicker limit value G.

FIG. 4a shows in a Cartesian coordinate system by way of example two not-to-scale power frequency curves P ₁ (f) and P ₂ (f) for the second combination of control types. The output powers P ₁ and P _{2 of} the heating frequency units 10a, 12a are plotted on an ordinate axis 58. On an abscissa axis 60, the frequency f is plotted. The target powers P _obj1 and P _{obj2 of} the heating frequency units 10a, 12a are set by an operator. In the first time interval T _A , the first heating frequency unit 10a is operated at a frequency f _1A and the second heating frequency unit 12a is operated at a frequency f _2A . In the second time interval T _B , the first heating frequency unit 10a is operated at a frequency f _1B and the second heating frequency unit 12a is operated at a frequency f _2B . The frequencies f _1A and f _2A and f _1B and f _2B each form a set of frequencies (f _1A , f _2A ), (f _1B , f _2B ), where the two frequencies of a set of frequencies (f _1A , f _2A ), (f _1B , f _2B ) differ by 18 kHz. The control mode used here (f _1X , f _2X ) is identical in both time intervals: The two heating frequency units 10a, 12a are operated in the time interval T _X with a frequency difference k of 18 kHz (4). Even if the same type of control is used in both time intervals T _A , T _B, the frequencies used are f _1A , f _2A , f _1B , f _2B .

FIG. 4b shows in a Cartesian coordinate system by way of example two not-to-scale power-time curves P ₁ (t) and P ₂ (t) for the second combination of control types FIG. 4a , The output powers P ₁ and P _{2 of} the heating frequency units 10 a, 12 a are plotted on an ordinate axis 62. On an abscissa axis 64, the time t is plotted. An in FIG. 4b illustrated course of the power-time curves P ₁ (t) and P ₂ (t) is in a heating operation state of the heating-frequency units 10 a, 12 a periodically through the period T. The first heating frequency unit 10a is operated in the first time interval T _A with a larger output power P ₁ than in the second time interval T _B. By contrast, the second heating frequency unit 12a is operated in the first time interval T _A with a smaller output power P ₂ than in the second time interval T _B. The total output power P ₁ + P ₂ is temporally constant and identical to the sum of the desired power P _obj1 + P _obj2 .

Since the largest maximum fluctuation of the output powers of the heating frequency units 10a, 12a for the second combination of control types (f _1X , f _2X ) according to FIG. 4b is smaller than for the first combination of control _types (f _1X , f _2X ) according to FIG. 3b , the control unit 14a selects the second combination of control modes (f _1X , f _2X ) for the joint operation of the two heating-frequency units 10a, 12a.

In the FIG. 5 a further embodiment of the invention is shown. The following descriptions are essentially limited to the differences between the embodiments, with respect to the same components, features and functions on the description of the other embodiment, in particular the FIGS. 1, 2 . 3a-d and 4a-b , can be referenced. To distinguish the embodiments, the letter a in the reference numerals of the embodiment in the FIGS. 1, 2 . 3a-d and 4a-b by the letter b in the reference numerals of the embodiment of FIG. 5 replaced. With respect to identically designated components, in particular with regard to components with the same reference numerals, can in principle also to the drawings and / or the description of the embodiment of FIGS. 1, 2 . 3a-d and 4a-b to get expelled.

$$\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{+}\mathrm{\dots }\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\mathrm{-}\mathrm{\dots }\mathrm{-}{\mathrm{P}}_{\mathrm{objN}}\right|\mathrm{\le }\mathrm{G}\mathrm{,}$$

... $$\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{+}\mathrm{\dots }\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\mathrm{-}\mathrm{\dots }\mathrm{-}{\mathrm{P}}_{\mathrm{objN}}\right|\mathrm{\le }\mathrm{G}\mathrm{,}$$

$${\mathrm{P}}_{\mathrm{ave}\mathrm{1}}\mathrm{=}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{+}\mathrm{\dots }\mathrm{+}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{N}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{,}$$

$${\mathrm{P}}_{\mathrm{ave}\mathrm{2}}\mathrm{=}{\mathrm{P}}_2\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_2\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{+}\mathrm{\dots }\mathrm{+}{\mathrm{P}}_2\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{N}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{obj}2}\mathrm{,}$$

$${\mathrm{P}}_{\mathrm{aveN}}\mathrm{=}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{+}\mathrm{\dots }\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{N}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{objN}}$$

und $${\mathrm{f}}_{\min \mathrm{1}\mathrm{/}\mathrm{2}/\dots /\mathrm{N}}\mathrm{\le }{\mathrm{f}}_{\mathrm{nX}}\mathrm{\le }{\mathrm{f}}_{\max },$$

wobei t_x einen beliebigen Zeitpunkt innerhalb des Zeitintervalls T_X, P_n die Ausgangsleistung der n-ten Heizfrequenzeinheit 10b, 12b und P_objn die Sollleistung der n-ten Heizfrequenzeinheit 10b, 12b bezeichnet. Eine Auswahl der Steuerungsarten (f_1X, f_2X, ..., f_NX) für die N Zeitintervalle T_x erfolgt analog zur Auswahl im vorhergehenden Ausführungsbeispiel.The above-described method is easily applicable to a cooking appliance apparatus having N simultaneous heating frequency units 10b, 12b, as in FIG FIG. 5 in an off-scale representation of power-time curves P _n (t) with n = 1, 2, ..., N shown by way of example. In this case, a control unit 14b divides a period T into N time intervals T _X (X = A, B, ..., N) and operates the N heating frequency units 10b, 12b in each of the time intervals T _X with a control mode (f _1X , f _2X , ..., f _NX ). As in the previous embodiment, the control unit 14b selects for each time interval T _X a control mode (f _1X , f _2X , ..., f _NX ) from a catalog of control _modes (f _1X , f _2X , ..., f _NX ). This catalog includes at least the following types of control: (1) All heating frequency units 10b, 12b are operated at the same non-zero frequency in the time interval T _X. (2) Of the heating-frequency units 10b, 12b, y heating-frequency units 10b, 12b are switched off, where y = 1, 2,..., N. (3) At least two heating-frequency units 10b, 12b differ in their frequency _f.sub.nX (n = 1 , 2, ..., N) by a frequency difference k. It should be noted that the _{types of} control (f _1X , f _2X , ..., f _NX ) marked with (2) are actually N types of control (f _1X , f _2X , ..., f _NX ), since the number of disconnected Heizfrequenzeinheiten 10b, 12b, a distinguishing feature of two different types of control (f _{1X, 2X} f, ..., f _NX) represents. Furthermore, the _{types of} control (f _1X , f _2X , ..., f _NX ) marked with (3) are also several types of control (f _1X , f _2X , ..., f _NX ). For the person skilled in the art, it is obvious that by combining two of the control _types mentioned here (f _1X , f _2X ,..., F _NX ), in particular the control _modes (f _1X , f _2X , ..) marked with (2) and (3). ., f _NX ), new types of control (f _1X , f _2X , ..., f _NX ) can be formed. It is particularly advantageous if, in each of the N time intervals T _X, another of the N heating frequency _{units is} operated at a frequency f _nX and the remaining (N-1) heating frequency _{units are} operated at a frequency (f _nX ± k) in the same time interval T _X , where k = 18 kHz is particularly advantageous. The conditions mentioned in the preceding embodiment are generalized as follows: $$\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{+}\mathrm{...}\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\mathrm{-}\mathrm{...}\mathrm{-}{\mathrm{P}}_{\mathrm{objn}}\right|\mathrm{\le }\mathrm{G}\mathrm{.}$$

$$\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{+}\mathrm{...}\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\mathrm{-}\mathrm{...}\mathrm{-}{\mathrm{P}}_{\mathrm{objn}}\right|\mathrm{\le }\mathrm{G}\mathrm{.}$$

... $$\left|{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{2}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{+}\mathrm{...}\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{-}{\mathrm{P}}_{\mathrm{obj}\mathrm{2}}\mathrm{-}\mathrm{...}\mathrm{-}{\mathrm{P}}_{\mathrm{objn}}\right|\mathrm{\le }\mathrm{G}\mathrm{.}$$

$${\mathrm{P}}_{\mathrm{ave}\mathrm{1}}\mathrm{=}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{+}\mathrm{...}\mathrm{+}{\mathrm{P}}_{\mathrm{1}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{N}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{obj}\mathrm{1}}\mathrm{.}$$

$${\mathrm{P}}_{\mathrm{ave}\mathrm{2}}\mathrm{=}{\mathrm{P}}_2\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_2\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{+}\mathrm{...}\mathrm{+}{\mathrm{P}}_2\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{N}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{obj}2}\mathrm{.}$$

$${\mathrm{P}}_{\mathrm{Aven}}\mathrm{=}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{A}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{A}}\mathrm{/}\mathrm{T}\right)\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{B}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{B}}\mathrm{/}\mathrm{T}\right)\mathrm{+}\mathrm{...}\mathrm{+}{\mathrm{P}}_{\mathrm{N}}\left({\mathrm{t}}_{\mathrm{N}}\right)\mathrm{\times }\left({\mathrm{T}}_{\mathrm{N}}\mathrm{/}\mathrm{T}\right)\mathrm{=}{\mathrm{P}}_{\mathrm{objn}}$$

and $${\mathrm{f}}_{\min \mathrm{1}\mathrm{/}\mathrm{2}/.../\mathrm{N}}\mathrm{\le }{\mathrm{f}}_{\mathrm{nX}}\mathrm{\le }{\mathrm{f}}_{\mathrm{Max}}.$$

where t _x denotes an arbitrary time within the time interval T _X , P _n denotes the output power of the n-th heating frequency unit 10b, 12b, and P _{objn denotes} the target power of the n-th heat frequency unit 10b, 12b. A selection of the control _modes (f _1X , f _2X , ..., f _NX ) for the N time intervals T _x is analogous to the selection in the previous embodiment.

Alternatively, in both embodiments, a memory unit may be provided in which characteristic power frequency curves P _n (f, d _j ) are stored for various typical combinations of cooking utensils and induction heating elements. Storage then preferably takes place by a manufacturer before delivery of a corresponding induction hob. This makes it possible to dispense with measuring the power-frequency curves P _n (f, d _j ) before starting a heating operation.

reference numeral

10

Heizfrequenzeinheit

12

Heizfrequenzeinheit

14

control unit

16

Induction hob

18

Hotplate

20

heating zone

22

heating zone

26

operating element

28

display element

30

Operating and display unit

32

Control unit

36

axis of ordinates

38

abscissa

42

axis of ordinates

44

abscissa

46

axis of ordinates

48

abscissa

50

axis of ordinates

52

abscissa

54

axis of ordinates

56

abscissa

58

axis of ordinates

60

abscissa

62

axis of ordinates

64

abscissa

d _j

Duty cycle (j = 1, ..., n)

D _1A

duty cycle

D _1B

duty cycle

D _1C

duty cycle

D _2A

duty cycle

D _2B

duty cycle

F

Total output power difference

f

frequency

f _1A

frequency

f _1B

frequency

f _2A

frequency

f _2B

frequency

f _min1

minimum frequency

f _min2

minimum frequency

f _max

High frequency

f _nX

frequency

f _obj1

nominal frequency

f _obj2

nominal frequency

G

Flickergrenzwert

k

frequency difference

P ₁

output

P ₁ (f)

Power-frequency curve

P ₁ (f, d _j )

Power-frequency curve

P ₁ (t)

Power-time curve

P ₂

output

P ₂ (f)

Power-frequency curve

P ₂ (f, _dj )

Power-frequency curve

P _n (f, d _j )

Power-frequency curve

P ₂ (t)

Power-time curve

P _ave1

Average output power

P _ave2

Average output power

P _n

output

P _n (t)

Power-time curve

P _obj1

target power

P _obj2

target power

P _objn

target power

T

period

T _0A

period

T _0B

period

T _A

time interval

T _B

time interval

T _X

time interval

t

Time

t _0A

on time

t _0B

on time

t ₁

time

t ₂

time

t _X

time

V ₀

Switch-on

V ₁ (t)

control signal

V ₁

control voltage

V ₂ (t)

control signal

x

time

y

number

Claims (10)

Cooking appliance device with at least one first and at least one second heating frequency unit (10, 12) and with at least one control unit (14) which is provided to operate the at least two heating frequency units (10, 12) together periodically with a period duration (T) and Period (T) in at least two time intervals (T _A , T _B ) to divide, characterized in that the control unit (14) is provided for each of the at least two time intervals (T _A , T _B ) a control _mode (f _1X , f _2X ) from a catalog of control _modes (f _1X , f _2X ). Cooking appliance device according to claim 1, characterized in that the control unit (14) is provided to select those types of control (f _1X , f _2X ) for the at least two time intervals (T _A , T _B ), the operation of the at least two Heizfrequenzeinheiten (10 , 12) with as small fluctuations as possible of a total output power of the at least two heating frequency units (10, 12) and / or a respective output power (P ₁ , P ₂ ) of the at least two heating frequency units (10, 12). Cooking appliance device according to claim 1 or 2, characterized in that the control unit (14) is provided according to the selected control _modes (f _1X , f _2X ) for each of the at least two time intervals (T _A , T _B ) frequencies (f _1A , f _2A , f _1B , f _2B ) of control signals (V ₁ (t), V ₂ (t)) of the at least two heating frequency units (10, 12) while at least substantially keeping constant a total output power (P) of the at least two heating frequency units (10, 12 ). Cooking appliance device according to one of the preceding claims, characterized in that the control unit (14) is provided for _adapting average output _powers (P _ave1 , P _ave2 ) of the at least two heating frequency units (10, 12) to selected desired powers (P _obj1 , P _obj2 ). Cooking device according to claim 4, characterized in that the control unit (14) is provided for adapting the average output _powers (P _ave1 , P _ave2 ) of the at least two heating frequency units (10, 12) by adapting the at least two time intervals (T _A , T _B ). Cooking appliance device according to one of the preceding claims, characterized in that the control unit (14) is provided to control the at least two heating frequency units (10, 12) in each case by means of a control signal (V ₁ (t), V ₂ (t)) and / or to adjust and, in at least one operating condition, to adjust a duty cycle (D _1A , D _2A , D _1B , D _2B ) of at least one of the control signals (V ₁ (t), V ₂ (t)). Cooking apparatus according to one of the preceding claims, characterized in that the control unit (14) is arranged to subdivide the period (T) into a number of time intervals (T _A , T _B ) corresponding to a number of heating frequency units (10, 12). Cooking device according to one of the preceding claims, characterized in that the control unit (14) is provided to power frequency curves (P ₁ (f, d _j ), P ₂ (f, d _j )) for different duty cycles (d _j ) of a control signal (V ₁ (t), V ₂ (t)) of the at least two heating frequency units (10, 12). Method with a cooking device device having at least one first and at least one second heating frequency unit (10, 12), in particular according to one of the preceding claims, in which the heating frequency units (10, 12) are operated together periodically with a period duration (T) and the period duration (T ) is subdivided into at least two time intervals (T _A , T _B ), characterized in that for each of the at least two time intervals (T _A , T _B ) to minimize intermodulation noises a control _mode (f _1X , f _2X ) from a catalog of control types (f _1X , f _2X ) is selected. Cooking appliance, in particular hob, with a cooking appliance device according to one of claims 1 to 8.

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