EP1494505B1 - Method and device of power control of induction cooktops - Google Patents

Method and device of power control of induction cooktops Download PDF

Info

Publication number
EP1494505B1
EP1494505B1 EP04405263A EP04405263A EP1494505B1 EP 1494505 B1 EP1494505 B1 EP 1494505B1 EP 04405263 A EP04405263 A EP 04405263A EP 04405263 A EP04405263 A EP 04405263A EP 1494505 B1 EP1494505 B1 EP 1494505B1
Authority
EP
European Patent Office
Prior art keywords
inductor
control
length
energy
period
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP04405263A
Other languages
German (de)
French (fr)
Other versions
EP1494505A2 (en
EP1494505A3 (en
Inventor
Heinrich Weder
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Elatronic AG
Original Assignee
Elatronic AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Elatronic AG filed Critical Elatronic AG
Publication of EP1494505A2 publication Critical patent/EP1494505A2/en
Publication of EP1494505A3 publication Critical patent/EP1494505A3/en
Application granted granted Critical
Publication of EP1494505B1 publication Critical patent/EP1494505B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H05B6/062—Control, e.g. of temperature, of power for cooking plates or the like
    • H05B6/065—Control, e.g. of temperature, of power for cooking plates or the like using coordinated control of multiple induction coils

Definitions

  • the present invention relates to a method for power regulation of induction cookers with a plurality of cooking zones, each of these cooking zones having an inductor, and a device for carrying out this method.
  • a cooking device generally has at least two juxtaposed induction hotplates, one of which comprises an inductor.
  • the heating or heating of the vessel with the food is known to be done by induction of eddy currents in a vessel.
  • One of the basic conditions for the induction of eddy currents in the vessel is an alternating electromagnetic field. This is generated in the cooking zone of an induction cooker by means of a time-varying electric current through the cooking zone, which is one of the components of an electrical resonant circuit. This resonant circuit is excited by a clock source and it generates the necessary for the induction of eddy currents in the vessel alternating current.
  • the cooking or cooking operations require that different amounts of energy to be supplied to the adjacent cooking vessels. Therefore, known induction cookers also have the ability to control the amount of energy supplied to the cooking vessels.
  • This power control or regulation can basically be done in two ways. On the one hand, the power control or regulation can be achieved by changing the frequency of the current flowing in the inductor resonant circuit electrical current. The range of these frequencies is usually between 22KHz and 45KHz, ie in a range which is above the range of audible frequencies. On the other hand, the power control or regulation can be effected by changes in the duration or length or width of the current pulses flowing through the inductor.
  • This electromagnetic induction cooker includes a resonant circuit having an induction coil to which a cookware, such as a pan, can be assigned.
  • the variable electromagnetic field generated in the induction coil and acting on the cookware induces eddy currents in the cookware, which, due to the ohmic resistance, produce the heat required for the cooking or cooking process in the cookware.
  • a transistor is arranged, which is turned on via a control signal, that is made conductive, or turned off, that is made non-conductive.
  • the energy averaged over time ie the average power supply to the coil and thus to the cookware, can be adjusted.
  • a pulse width control device is provided in this induction cooker. Since the induction coil is connected in series with only one transistor switch in this induction cooker, only current pulses in a current direction can be generated in the coil.
  • the object of the present invention is to eliminate the mentioned disadvantage as well as other disadvantages of the known induction cookers.
  • the respective cooking point 3 further comprises a drive device or a power source 4 for the induction hotplate 5 (FIG. Fig. 2 ).
  • This drive device 4 includes an inverter 8 and a control device 9 for the inverter 8.
  • the inductor 13 of the respective juxtaposed cooking zones 3 is connected to a separate and controllable source 4, from which the inductor 13 can be energized.
  • control device 9 is inter alia a microprocessor 10, in which, among other programs can be stored, which the course of each applied Gar-. or cooking process can control.
  • the operation of the microprocessor 10 can by means of a in Fig. 2 only schematically indicated operating device 23 can be influenced.
  • This device 23 includes, inter alia, a component above which values can be entered by the operator for the desired cooking process.
  • Corresponding operating devices are available on the market and belong to the state of the art. Typically, potentiometers or tiptasts with electronic control logic are used for such function.
  • the microprocessor 10 is provided with a technical interface 24 for the connection of further devices (not shown), by means of which the microprocessor 10 can be programmed, for example.
  • the technical interface 24 is designed as a bidirectional communication interface. This interface can operate according to a valid standard such as RS-232, RS-485, Ethernet, USB or similar.
  • proprietary control lines are available via which synchronization points, alarm signals or control signals of the method can be queried.
  • the microprocessor 10 is connected via a control bus 22 to a device 20 for processing the output from the microprocessor 10 control signals.
  • the signal processing device 20 may be implemented as a standard module in which a custom electronic circuit is programmed. A PGA is preferred or an equivalent building block can be used.
  • This processing device 20 is connected via control lines 7A and 7B to the corresponding inputs A and B of the inverter 8.
  • the inverter 8 represents a controlled power stage of the present device. This means that the inverter 8 can control the current flow through the inductor 13 on the basis of the pulses supplied to it by the microprocessor 10.
  • the inductor 13, which is designed as a coil, together with at least one capacitor 15 or 16 forms a resonant circuit.
  • the induction coil 13 and the capacitor 15 and 16 are designed so that the parameters thereof are not changeable. These parameters are chosen so that the resonant frequency of this resonant circuit is well below the operating frequency of 22kHz of this submission for all power regulation ranges.
  • the resonant frequency of the resonant circuit can be in the range between 16 and 20 kHz.
  • the inductor 13 thus represents a central component of the inverter 8, by means of which energy can be transmitted to the cooking vessels 6.
  • the inductor resonant circuit is formed bridge-like.
  • One of the branches of this bridge form the series-connected capacitors 15 and 16.
  • the free electrode of the first capacitor 15 is connected to the positive terminal of a source DC of the supply voltage.
  • the free electrode of the other capacitor 16 is connected to the negative terminal of the source DC of the supply voltage.
  • the opposite branch of the bridge form two series-connected power switching elements 25 and 26, which also belong to the resonant circuit and which are transistors in the illustrated case.
  • the collector of the first transistor 25 is connected in the illustrated case to the positive terminal of the voltage source DC.
  • To the base of this first transistor 25 is the first and received by the signal processing device 20 incoming control line 7A connected.
  • the emitter of this first transistor 25 is connected to the collector of the second transistor 26.
  • the second and from the signal processing device 20 incoming control line 7B is connected.
  • the emitter of this second transistor 26 is connected to the negative terminal of the voltage source DC.
  • the series-connected capacitors 15 and 16 have a tapping point 18 which lies between the interconnected electrodes of the capacitors 15 and 16. At this center tap point 18, one of the ends or connecting conductor 14 of the inductor coil 13 is connected. Between the emitter of the first power semiconductor 25 and the collector of the second power semiconductor 26, a further point 19 is present. At this center tap point 19, the second end and the second terminal conductor 17 of the inductor coil 13 is connected.
  • the power semiconductors 25 and 26 are designed as bipolar transistors. In particular, however, also embodiments with related power semiconductors are conceivable, such as e.g. IGBTs (Insulated gate bipolar transistors), MOS-FET transistors, thyristors, GTO's and triacs.
  • In the inverter 8 further sensors for the temperature monitoring of the power electronics and the vessel 6 and devices for measuring the current through the inductor 13 and the current performance of the inductor 5 are integrated (not shown). The results provided by these monitoring devices are fed back to the microprocessor 10 via the measuring leads 11.
  • These measuring lines 11 are signal lines which connect the inverter 8 to the microprocessor 10 and which are designed so that either digital or analog measured values from the inverter 8 in the Microprocessor 10 can be transmitted.
  • These signal lines 11 may include dedicated wire lines and a digital control bus.
  • the supply of the respective inductor 13 with energy takes place in pulses and periodically. This means that energy is supplied to the inductor 13 in the form of pulses and that these pulses are within successive or repetitive periods or time windows.
  • This situation is in Fig. 3, 4 and 5 illustrated by diagrams.
  • the time t is plotted on the X-axis of the respective diagram.
  • the individual periods or time windows of the energy supply to the inductors 13 are in all three superimposed Fig. 3 to 5 separated from each other by means of perpendicular to the X-axis and superimposed lines L.
  • a period or a time window is therefore designated LL in the following.
  • the time slots LL have the same length or width for all inductors 13. In addition, the beginnings and ends of the time slots are practically at the same time L.
  • the length or width of the repetitive time slots LL is expressed as Tmax ( Fig. 4 ) designated.
  • the length of the time window Tmax is the same for all cooking zones 3, so that the repetition frequency of feeding the neighboring inductors 13 with energy is practically the same for all inductors 13.
  • the Tmax is also constant for all inductors 13, ie invariable, and moreover chosen so that the length of Tmax corresponds to the period of the frequency of about 22kHz. This frequency corresponds to the operating frequency of about 22 kHz of the inductor resonant circuit in the inverter 8.
  • the inductors 13 of all cooking zones 3 are supplied in this frequency or frequency with the energy pulses.
  • the actual control of the power of the inductors 13 is, as already mentioned, by a pulse-like conduction of current I through the inductors 13 of the cooking zones 3 within the time window LL.
  • the electric power delivered to the respective inductor 13 is determined not only by the magnitude of the current I flowing through the coil 13, but also by that period of time during which this current I flows through the coil 13.
  • the period of time during which the current I flows through the inductor 13 is virtually identical to that period during which the relevant controllable switch 25 or 26 in the inverter 8 is conducting. Therefore, the timing of the current I through the inductor 13 can be described in connection with the timing of those pulses and those voltages A and B, which control the opening of the switching elements 25 and 26.
  • the parameters of the inverter 8 determine how large the current I is, which flows through the inductor 13 during the time period TA and TB, after the relevant switch 25 or 26 has been made conductive.
  • the course of the inductor 13 supplied power is in Fig. 5 represented by the line W. In 3 and 4 appropriate lines W could be located.
  • the current I may have a constant value during the periods TA and TB in the present case.
  • the impulse A in Fig. 3 to 5 shows the time course of that control voltage US during a time window LL, which is applied via the line 7A to the base of the first transistor 25.
  • the momentum B in Fig. 3 to 5 which follows the first pulse A, shows the time profile of that control voltage US during a time window LL, which is applied via the line 7B to the base of the second transistor 26.
  • the drive signals A and B are practically rectangular signals.
  • the size of the control voltages US is between 0 volts and a maximum appropriate drive voltage US, which is useful for the operation of the switches 25 and 26. These control pulses A and B have the same polarity.
  • the generation of the first control pulse A always begins at the beginning or shortly after the beginning of the respective time window LL or the respective period Tmax, i. at the time 0 of the time slot LL or shortly thereafter, regardless of how long the pulses A and B last.
  • the control pulse B is generated after the pulse A, and only after the lapse of a short period, which is between these two pulses and which is related to the discharge times in the switches 25 and 26.
  • Fig. 3 shows the length TA and TB of the control pulses A and B for the maximum supply of the inductor 13 with energy.
  • Fig. 5 shows the length TA and TB of the control pulses A and B for a minimum supply of the inductor 13 with energy.
  • Fig. 4 shows the length TA and TB of the control pulses A and B for a middle power range of the inductor 13.
  • Tmax which corresponds to the length of the time window LL.
  • the sum S of the two durations TA and TB is always smaller than Tmax.
  • the first control pulse A makes the transistor 26 conductive and the current I in this case flows from the negative terminal DC- through this transistor 26, the intermediate tap between the transistors 25 and 26 19, the coil 13, lying between the capacitors 15 and 16 Center tap 18 and the capacitors 15 and 16 to the positive terminal DC + the DC voltage source DC.
  • a pulse B passes via the line 7B to the base of the other transistor 25 and makes it conductive.
  • the current I now flows from the positive terminal DC + through this transistor 25, the transistor center tap 19, the coil 13, but now in the opposite direction, the capacitor center tap 18 and the capacitors 15 and 16 to the minus terminal DC- of the DC voltage source DC.
  • the time period TA or TB could be virtually zero for power regulation. However, for technical reasons, this choice does not make much sense.
  • a sum S of TA and TB is preferred, which corresponds to the period length Tmin of a frequency.
  • the present method offers not only the advantage that the power in each hob 3 can be controlled individually, but also the important advantage that the supply network for the electrical energy is not pulsed but continuously charged. This is because the TA and TB are extended and shortened simultaneously and always by the same amount. This is important because the cooking stations 3 usually draw several amperes of power from the supply network at their peak outputs.
  • the present method can also be carried out in a controlled manner by measuring signals via the measuring lines 11 to the microprocessor 10th be forwarded.
  • the microprocessor 10 controls the magnitude of the inductor current I, its zero crossing, the timing for the switching of the control lines 7A and 7B, etc., based on measured values from the measuring lines 11.
  • the entire cooking process can also be monitored and regulated in this way.
  • a large saucepan 6 filled with water requires a different kind of operation than the cooking zone 3, for example a frying pan with a fried egg.
  • no cooking process may be started when other metallic objects such as a fork or a wooden spoon are on the stove.
  • An extension of the present method is that the nature of the vessel 6 is continuously detected on the stove plate 2 via measuring pulses.
  • the control pulses A and B for the switches 25 and 26 are preceded by pulses (not shown) whose length is smaller than the length of the control pulses A and B.
  • These measuring pulses arrive in the manner described for the control pulses A and B. Way to the inductor 13 of the hob plate 2, on which the cooking vessel 6 rests. According to the nature of this cooking vessel 6, the measuring pulses are influenced and such a response then passes via one of the measuring lines 11 to the microprocessor 10, which among other things controls the operation of the inverter 8.
  • Fig. 8 two diagrams relating to this issue are superimposed.
  • the control voltage US for the switches 25 and 26 is discharged.
  • the current IS is discharged through the inductor 13.
  • Fig. 8 It can be seen that there can be a phase shift between the coil current IS and the control voltage US. The size of this phase shift depends on the type or quality of the vessel or of the object located on the stove top 2 dependent.
  • the magnitude of the phase shift is determined by the inductor 13 over the time difference DT between the zero crossing of the control voltage US and the zero crossing of the current IS. The smaller this time difference DT, the better the quality of the vessel 6, so that a cooking process can be started by the inverter 8.
  • the control device 9 takes the inverter 8 and thus also plate 5 is not in operation or it turns off the inverter 8 and thus also this hotplate 3 off.
  • a collection of corresponding step responses is stored in the memory of the microprocessor 10.
  • a specific time-dependent regulated power control of the cooking process is performed in the memory of the microprocessor.
  • a sequence of time-changeable time intervals TA resp. TB stored in the memory of the microprocessor.
  • the information about the food to be cooked, the cooking progress, etc. are supplied to the microprocessor 10 via the measuring lines 11.
  • external sensors are used, such as an external temperature sensor 27, which can be plugged into the food and which thus the status of the Cooking process via a corresponding measuring line 11 to the microprocessor 10 reports.
  • Fig. 6 shows an embodiment of a supply device 30 for the inductor 13, when the supply of the same is to be made with energy from a three-phase supply network.
  • the feeding device 30 includes, inter alia, three phase terminals L1, L2 and L3 to the utility grid. Connected to the three phase terminals L1, L2 and L3 is a rectifier 28, which is implemented as a three-phase bridge rectifier.
  • This converter converts the AC voltage from the supply network into a DC voltage, which can appear at the output terminals DC + and DC- of this supply device 30.
  • a smoothing capacitor C Between the output terminals DC + and DC- of the three-phase bridge rectifier 28 is a smoothing capacitor C.
  • the DC voltage for the inductor 13 is tapped and by the LC resonant circuit or through the bridge in the inverter. 8 fed to the inductor 13.
  • the feed device 30 may also be configured to limit the power drawn by the present device from the mains. This power limitation is necessary in order to keep the consumption of the stove to energy in the context of the permitted during the building installation energy extraction.
  • a current measuring device 29 is turned on, which is connected upstream of the bridge rectifier 28.
  • the output of the current measuring device 29 is connected to one of the inputs of the control device 9.
  • maximum permissible currents are adjustable in the control device 9 as a control parameter.
  • the control device 9 regulates the maximum power consumption of the inductor 13 in such a way that the maximum power drawn by the building installation nevertheless does not exceed a permissible value.
  • the present device can also be powered from a single-phase network.
  • the feed device 31 has a single-phase bridge rectifier 32, which can be connected via terminals N and L to the single-phase supply network.
  • the current measuring device 29 is located in the connection conductor L in this case.
  • the method according to the invention offers, inter alia, the possibility that the magnitude of the power of the individual cooking zones 3 in an induction cooker 1 can be controlled simultaneously and individually without generating any audible noise, for example whistling sounds, normally caused by interferences between adjacent inductors 13. Consequently, co-located cooking zones 3 can be operated in an induction cooker 1 with different powers, without causing the mentioned noise.
  • the present method provides, inter alia, the advantages that the supply network for electrical energy is charged without power surges and that the cooking process is uniform. The method can also be applied in the case when as Supply voltage for the inverter 8 is intended to serve a multiphase AC voltage.

Abstract

The hob unit (2) has cooking rings (3) comprising an induction heating zone (5) in a frame (1). Each inductor is separately supplied with energy from an energy source in fixed periods which are controlled by a microprocessor to give different levels of heating.

Description

Die vorliegende Erfindung betrifft ein Verfahren zur Leistungsregulierung von Induktionskochherden mit mehreren Kochstellen, wobei jede dieser Kochstellen einen Induktor aufweist, sowie eine Einrichtung zur Durchführung dieses Verfahrens.The present invention relates to a method for power regulation of induction cookers with a plurality of cooking zones, each of these cooking zones having an inductor, and a device for carrying out this method.

Eine Kocheinrichtung weist im allgemeinen zumindest zwei nebeneinander angeordnete Induktionskochplatten auf, von welchen je eine einen Induktor umfasst. Bei einem Induktionskochherd erfolgt die Erwärmung oder Erhitzung des Gefässes mit dem Gargut bekanntlich durch Induktion von Wirbelströmen in einem Gefäss. Eine der Grundbedingungen für die Induktion von Wirbelströmen im Gefäss ist ein elektromagnetisches Wechselfeld. Dieses wird in der Kochstelle eines Induktionskochherdes mittels eines sich zeitlich ändernden elektrischen Stroms durch den Kochstelleninduktor erzeugt, welcher einen der Bestandteile eines elektrischen Schwingkreises darstellt. Dieser Schwingkreis wird durch eine Taktquelle angeregt und er erzeugt den für die Induktion von Wirbelströmen im Gefäss notwendigen Wechselstrom.A cooking device generally has at least two juxtaposed induction hotplates, one of which comprises an inductor. In an induction cooker, the heating or heating of the vessel with the food is known to be done by induction of eddy currents in a vessel. One of the basic conditions for the induction of eddy currents in the vessel is an alternating electromagnetic field. This is generated in the cooking zone of an induction cooker by means of a time-varying electric current through the cooking zone, which is one of the components of an electrical resonant circuit. This resonant circuit is excited by a clock source and it generates the necessary for the induction of eddy currents in the vessel alternating current.

Die Koch- bzw. Garvorgänge erfordern, dass unterschiedlich grosse Mengen von Energie den nebeneinander stehenden Kochgefässen zugeführt werden. Deswegen weisen bekannte Induktionskocherde auch die Möglichkeit einer Steuerung der Menge der den Kochgefässen zugeführten Energie auf. Diese Leistungssteuerung bzw.- Regelung kann grundsätzlich auf zwei Arten erfolgen. Zum einen kann die Leistungssteuerung bzw. -regelung durch Änderungen der Frequenz des im Induktor-Schwingkreis fliessenden elektrischen Stromes erreicht werden. Der Bereich dieser Frequenzen liegt meistens zwischen 22KHz und 45KHz, d.h. in einem Bereich, welcher oberhalb des Bereiches der hörbaren Frequenzen liegt. Zum anderen kann die Leistungssteuerung bzw. - regelung durch Änderungen der Dauer bzw. Länge bzw. Breite der durch den Induktor fliessenden Stromimpulse bewirkt werden.The cooking or cooking operations require that different amounts of energy to be supplied to the adjacent cooking vessels. Therefore, known induction cookers also have the ability to control the amount of energy supplied to the cooking vessels. This power control or regulation can basically be done in two ways. On the one hand, the power control or regulation can be achieved by changing the frequency of the current flowing in the inductor resonant circuit electrical current. The range of these frequencies is usually between 22KHz and 45KHz, ie in a range which is above the range of audible frequencies. On the other hand, the power control or regulation can be effected by changes in the duration or length or width of the current pulses flowing through the inductor.

Ein Verfahren und eine Vorrichtung zum Steuern des Leistungspegels in einem elektromagnetischen Induktionskocher ist z.B. in der Patentschrift US 5,004,881 beschrieben. Dieser elektromagnetische Induktionskocher enthält einen Schwingkreis, der eine Induktionsspule aufweist, der ein Kochgeschirr, wie z.B. eine Pfanne, zugeordnet werden kann. Das in der Induktionsspule erzeugte und auf das Kochgeschirr einwirkende veränderliche elektromagnetische Feld induziert Wirbelströme in dem Kochgeschirr, die aufgrund des ohmschen Widerstands die für den Koch- bzw. Garvorgang notwendige Wärme in dem Kochgeschirr erzeugen. In dem Schwingkreis ist ausserdem ein Transistor angeordnet, der über ein Steuersignal eingeschaltet, d.h. leitend gemacht wird, oder ausgeschaltet, d.h. nicht-leitend gemacht wird. Über das Verhältnis der Zeitdauer, während der der Transistor leitend ist, und der Zeitdauer, während der der Transistor nicht-leitend ist, kann die über die Zeit gemittelte Energiezufuhr, d.h. die durchschnittliche Leistungszufuhr an die Spule und somit an das Kochgeschirr eingestellt werden. Für diese Pulsweiten-Modulation ist bei diesem Induktionskocher eine Pulsweiten-Steuerungsvorrichtung vorgesehen. Da bei diesem Induktionskocher die Induktionsspule mit nur einem Transistorschalter in Serie geschaltet ist, können in der Spule nur Stromimpulsen in einer Stromrichtung erzeugt werden.A method and apparatus for controlling the power level in an electromagnetic induction cooker is disclosed in, for example, the patent US 5,004,881 described. This electromagnetic induction cooker includes a resonant circuit having an induction coil to which a cookware, such as a pan, can be assigned. The variable electromagnetic field generated in the induction coil and acting on the cookware induces eddy currents in the cookware, which, due to the ohmic resistance, produce the heat required for the cooking or cooking process in the cookware. In the resonant circuit also a transistor is arranged, which is turned on via a control signal, that is made conductive, or turned off, that is made non-conductive. By the ratio of the length of time during which the transistor is conductive and the period of time during which the transistor is nonconductive, the energy averaged over time, ie the average power supply to the coil and thus to the cookware, can be adjusted. For this pulse width modulation, a pulse width control device is provided in this induction cooker. Since the induction coil is connected in series with only one transistor switch in this induction cooker, only current pulses in a current direction can be generated in the coil.

Während des Betriebes der vorbekannten Kochherde kommt es oft vor, dass je ein Kochtopf auf dem jeweiligen Induktor steht, wobei diese Induktoren aus einer gemeinsamen Energiequelle gespeist werden. Wenn die Leistung der einzelnen Kochstellen durch Änderung der Frequenz des durch die Schwingkreise fliessenden Stromes gesteuert wird, dann können sich die Frequenzen der Induktoren in den benachbarten Kochstellen voneinander subtrahieren, sodass ein hörbarer und sehr unangenehmer Pfeifton entstehen kann.During operation of the known cookers, it often happens that a cooking pot is on the respective inductor, these inductors are fed from a common energy source. If the power of the individual cooking zones is controlled by changing the frequency of the current flowing through the oscillating circuits, then the Subtract the frequencies of the inductors in the adjacent cooking zones, so that an audible and very unpleasant whistling sound can occur.

Die Aufgabe der vorliegenden Erfindung ist, den genannten Nachteil sowie noch weitere Nachteile der bekannten Induktionskochherde zu beseitigen.The object of the present invention is to eliminate the mentioned disadvantage as well as other disadvantages of the known induction cookers.

Diese Aufgabe wird beim Verfahren der eingangs genannten Gattung in der Weise gelöst, wie dies im kennzeichnenden Teil des Patentanspruchs 1 definiert ist.This object is achieved in the method of the type mentioned in the manner as defined in the characterizing part of patent claim 1.

Die genannte Aufgabe wird auch durch eine Einrichtung gelöst, welche im kennzeichnenden Teil des Patentanspruchs 7 definiert ist.The above object is also achieved by a device which is defined in the characterizing part of claim 7.

Nachstehend werden Ausführungsformen der vorliegenden Erfindung anhand der beiliegenden Zeichnungen näher erläutert. Es zeigt:

  • Fig. 1 in einer Draufsicht und schematisch einen Induktionskochherd mit vier Induktionskochstellen,
  • Fig. 2 eine erste Ausführung einer der Kochstellen gemäss Fig. 1 mit einem Induktor,
  • Fig. 3 ein Diagramm, welches die Ansteuerung der Speisung des Induktors bei voller Leistung zeigt,
  • Fig. 4 ein Diagramm, welches die Ansteuerung der Speisung des Induktors bei einer mittleren Leistung zeigt,
  • Fig. 5 ein Diagramm, welches die Ansteuerung der Speisung des Induktors bei einer niedrigen Leistung zeigt,
  • Fig. 6 ein Schaltschema einer Speisung der vorliegenden Einrichtung aus einem dreiphasigen Versorgungsnetz,
  • Fig. 7 ein Schaltschema einer Speisung der vorliegenden Einrichtung aus einem einphasigen Versorgungsnetz und
  • Fig. 8 ein zeitliches Verhalten von Spannung und Strom im Induktor für eine gegebene Güte eines auf dem Induktor aufgestellten Gefässes.
  • Fig. 1 zeigt schematisch und in Draufsicht einen Induktionskochherd 1, welcher zur Durchführung des vorliegenden Verfahrens geeignet ist. Dieser Kochherd besitzt eine Herdplatte 2, welcher im in Fig. 1 dargestellten Fall vier Induktionskochstellen 3 zugeordnet sind. Die jeweilige Kochstelle 3 umfasst eine Induktionskochplatte 5. Zur Induktionskochplatte 5 gehört ein Induktor 13
  • (Fig. 2), welcher sich auf einer Grundplatte 12 befindet, wobei der Induktor 13 der Unterseite der Herdplatte 2 in einer an sich bekannten Weise zugeordnet
  • ist. Der Induktor 13 ist aus einer Litze gewickelt, welche beispielsweise aus Kupfer ist. Die Grundplatte 12 ist vorzugsweise aus einem hitzebeständigen Material, wie beispielsweise aus Keramik.
Hereinafter, embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. It shows:
  • Fig. 1 in a plan view and schematically an induction hob with four induction hobs,
  • Fig. 2 a first embodiment of the cooking according to Fig. 1 with an inductor,
  • Fig. 3 a diagram showing the control of the supply of the inductor at full power,
  • Fig. 4 a diagram showing the control of the supply of the inductor at an average power,
  • Fig. 5 a diagram showing the control of the supply of the inductor at a low power,
  • Fig. 6 3 is a circuit diagram of a supply of the present device from a three-phase supply network,
  • Fig. 7 a schematic diagram of a supply of the present device from a single-phase supply network and
  • Fig. 8 a temporal behavior of voltage and current in the inductor for a given quality of a vessel placed on the inductor.
  • Fig. 1 shows schematically and in plan view an induction hob 1, which is suitable for carrying out the present method. This stove has a stove top 2, which in the in Fig. 1 illustrated case four induction cookers 3 are assigned. The respective hob 3 comprises an induction hotplate 5. The induction hotplate 5 includes an inductor 13
  • ( Fig. 2 ), which is located on a base plate 12, wherein the inductor 13 associated with the underside of the stove plate 2 in a manner known per se
  • is. The inductor 13 is wound from a strand of copper, for example. The base plate 12 is preferably made of a heat-resistant material, such as ceramic.

Die jeweilige Kochstelle 3 umfasst ferner eine Ansteuerungsvorrichtung bzw. eine Energiequelle 4 für die Induktionskochplatte 5 (Fig. 2). Diese Ansteuerungsvorrichtung 4 enthält einen Inverter 8 und eine Regelvorrichtung 9 für den Inverter 8. Der Induktor 13 der jeweiligen der nebeneinander angeordneten Kochstellen 3 ist an eine eigene und steuerbare Quelle 4 angeschlossen, aus welcher der Induktor 13 mit Energie versorgt werden kann.The respective cooking point 3 further comprises a drive device or a power source 4 for the induction hotplate 5 (FIG. Fig. 2 ). This drive device 4 includes an inverter 8 and a control device 9 for the inverter 8. The inductor 13 of the respective juxtaposed cooking zones 3 is connected to a separate and controllable source 4, from which the inductor 13 can be energized.

In der Regelvorrichtung 9 befindet sich unter anderem ein Mikroprozessor 10, in welchem unter anderem Programme gespeichert sein können, welche den Verlauf des jeweils angewandten Gar-. bzw. Kochverfahrens steuern können. Die Arbeitsweise des Mikroprozessors 10 kann mit Hilfe einer in Fig. 2 nur schematisch angedeuteten Bedienvorrichtung 23 beeinflusst werden. Diese Vorrichtung 23 umfasst unter anderem einen Bestandteil, über welchen Werte für den gewünschten Garvorgang vom Bedienungspersonal eingegeben werden können. Entsprechende Bedienteile sind auf dem Markt erhältlich und sie gehören zum Stand der Technik. In der Regel werden Potentiometer oder Tiptasten mit einer elektronischen Ansteuerungslogik für solche Funktion eingesetzt.In the control device 9 is inter alia a microprocessor 10, in which, among other programs can be stored, which the course of each applied Gar-. or cooking process can control. The operation of the microprocessor 10 can by means of a in Fig. 2 only schematically indicated operating device 23 can be influenced. This device 23 includes, inter alia, a component above which values can be entered by the operator for the desired cooking process. Corresponding operating devices are available on the market and belong to the state of the art. Typically, potentiometers or tiptasts with electronic control logic are used for such function.

Ferner ist der Mikroprozessor 10 mit einer technischen Schnittstelle 24 für den Anschluss weiterer Geräte (nicht dargestellt) versehen, durch welche der Mikroprozessor 10 beispielsweise programmiert werden kann. Die technische Schnittstelle 24 ist als eine bidirektionale Kommunikationsschnittstelle ausgebildet. Diese Schnittstelle kann nach einem gültigen Standard wie RS-232, RS-485, Ethernet, USB oder ähnlichem funktionieren. Zusätzlich stehen noch proprietäre Steuerleitungen zur Verfügung, über welche Synchronisationspunkte, Alarmsignale oder Steuersignale des Verfahrens abgefragt werden können.Furthermore, the microprocessor 10 is provided with a technical interface 24 for the connection of further devices (not shown), by means of which the microprocessor 10 can be programmed, for example. The technical interface 24 is designed as a bidirectional communication interface. This interface can operate according to a valid standard such as RS-232, RS-485, Ethernet, USB or similar. In addition, proprietary control lines are available via which synchronization points, alarm signals or control signals of the method can be queried.

Der Mikroprozessor 10 ist über einen Steuerbus 22 mit einer Vorrichtung 20 zur Aufarbeitung der vom Mikroprozessor 10 abgegebenen Steuersignale verbunden. Die Signal-Aufarbeitungsvorrichtung 20 kann als ein Standardbaustein ausgeführt sein, in welchem eine kundenspezifische elektronische Schaltung programmiert ist. Bevorzugt wird dabei ein PGA oder es kann ein äquivalenter Baustein verwendet werden. Diese Aufarbeitungsvorrichtung 20 ist über Steuerleitungen 7A und 7B mit den entsprechenden Eingängen A und B des Inverters 8 verbunden.The microprocessor 10 is connected via a control bus 22 to a device 20 for processing the output from the microprocessor 10 control signals. The signal processing device 20 may be implemented as a standard module in which a custom electronic circuit is programmed. A PGA is preferred or an equivalent building block can be used. This processing device 20 is connected via control lines 7A and 7B to the corresponding inputs A and B of the inverter 8.

Vom Inverter 8, an welchen andererseits der Induktor 13 angeschlossen ist, führen Leitungen 11 zum Mikroprozessor 10 zurück, auf welchen Messdaten vom Inverter 8 sowie vom Induktor 13 zum Mikroprozessor 10 übertragen werden können. Diese Daten können dem Mikroprozessor 10 Auskunft über die Bedingungen des Betriebes der vorliegenden Einrichtung anhand von entsprechenden Daten liefern.From the inverter 8, to which the inductor 13 is connected on the other hand, lines 11 lead back to the microprocessor 10, on which measurement data from the inverter 8 and the inductor 13 to the microprocessor 10 can be transmitted. This data can the microprocessor 10 information about the Provide conditions of operation of the present facility based on appropriate data.

Der Inverter 8 stellt eine gesteuerte Leistungsstufe der vorliegenden Einrichtung dar. Dies bedeutet, dass der Inverter 8 den Stromfluss durch den Induktor 13 aufgrund der ihm vom Mikroprozessor 10 zugeleiteten Impulse steuern kann. Der Induktor 13, welcher als eine Spule ausgeführt ist, bildet zusammen mit zumindest einem Kondensator 15 bzw. 16 einen Schwingkreis. Die Induktionsspule 13 und der Kondensator 15 bzw. 16 sind so ausgeführt, dass die Parameter derselben nicht veränderbar sind. Diese Parameter sind so gewählt, dass die Resonanzfrequenz dieses Schwingkreises für alle Bereiche der Leistungsregulierung deutlich unterhalb der Arbeitsfrequenz von 22kHz der vorliegenden Einreichung liegt. Die Resonanzfrequenz des Schwingkreises kann im Bereich zwischen 16 und 20 kHz liegen. Der Induktor 13 stellt somit einen zentralen Bestandteil des Inverters 8 dar, mittels welchem Energie an die Kochgefässe 6 übertragen werden kann.The inverter 8 represents a controlled power stage of the present device. This means that the inverter 8 can control the current flow through the inductor 13 on the basis of the pulses supplied to it by the microprocessor 10. The inductor 13, which is designed as a coil, together with at least one capacitor 15 or 16 forms a resonant circuit. The induction coil 13 and the capacitor 15 and 16 are designed so that the parameters thereof are not changeable. These parameters are chosen so that the resonant frequency of this resonant circuit is well below the operating frequency of 22kHz of this submission for all power regulation ranges. The resonant frequency of the resonant circuit can be in the range between 16 and 20 kHz. The inductor 13 thus represents a central component of the inverter 8, by means of which energy can be transmitted to the cooking vessels 6.

Im in Fig. 2 dargestellten Beispiel ist der Induktor-Schwingkreis brückenähnlich ausgebildet. Einer der Äste dieser Brücke bilden die in Serie geschalteten Kondensatoren 15 und 16. Die freie Elektrode des ersten Kondensators 15 ist an die positive Klemme einer Quelle DC der Versorgungsspannung angeschlossen. Die freie Elektrode des anderen Kondensatoren 16 ist an die negative Klemme der Quelle DC der Versorgungsspannung angeschlossen.Im in Fig. 2 the example shown, the inductor resonant circuit is formed bridge-like. One of the branches of this bridge form the series-connected capacitors 15 and 16. The free electrode of the first capacitor 15 is connected to the positive terminal of a source DC of the supply voltage. The free electrode of the other capacitor 16 is connected to the negative terminal of the source DC of the supply voltage.

Den gegenüberliegenden Ast der Brücke bilden zwei in Serie geschaltete Leistungsschaltelemente 25 und 26, welche ebenfalls zum Schwingkreis gehören und welche im dargestellten Fall Transistoren sind. Der Kollektor des ersten Transistors 25 ist im dargestellten Fall an die positive Klemme der Spannungsquelle DC angeschlossen. An die Basis dieses ersten Transistors 25 ist die erste und von der Signal-Aufarbeitungsvorrichtung 20 ankommende Steuerleitung 7A angeschlossen. Der Emitter dieses ersten Transistors 25 ist an den Kollektor des zweiten Transistors 26 angeschlossen. An die Basis dieses zweiten Transistors 26 ist die zweite und von der Signal-Aufarbeitungsvorrichtung 20 ankommende Steuerleitung 7B angeschlossen. Der Emitter dieses zweiten Transistors 26 ist an die negative Klemme der Spannungsquelle DC angeschlossen.The opposite branch of the bridge form two series-connected power switching elements 25 and 26, which also belong to the resonant circuit and which are transistors in the illustrated case. The collector of the first transistor 25 is connected in the illustrated case to the positive terminal of the voltage source DC. To the base of this first transistor 25 is the first and received by the signal processing device 20 incoming control line 7A connected. The emitter of this first transistor 25 is connected to the collector of the second transistor 26. At the base of this second transistor 26, the second and from the signal processing device 20 incoming control line 7B is connected. The emitter of this second transistor 26 is connected to the negative terminal of the voltage source DC.

Die in Serie verbundenen Kondensatoren 15 und 16 weisen einen Abgriffspunkt 18 auf, welcher zwischen den miteinander verbundenen Elektroden der Kondensatoren 15 und 16 liegt. An diesen Mittelabgriffspunkt 18 ist eines der Enden bzw. Anschlussleiter 14 der Induktorspule 13 angeschlossen. Zwischen dem Emitter des ersten Leistungshalbleiter 25 und dem Kollektor des zweiten Leistungshalbleiters 26 ist ein weiterer Angriffspunkt 19 vorhanden. An diesen Mittelabgriffspunkt 19 ist das zweite Ende bzw. der zweite Anschlussleiter 17 der Induktorspule 13 angeschlossen. Im dargestellten Fall sind die Leistungshalbleiter 25 und 26 als Bipolar-Transistoren ausgeführt. Insbesondere sind jedoch auch Ausführungen mit artverwandten Leistungshalbleitern denkbar, wie z.B. IGBTs (Insulated gate bipolar transistors), MOS-FET-Transistoren, Thyristoren, GTO's und Triacs.The series-connected capacitors 15 and 16 have a tapping point 18 which lies between the interconnected electrodes of the capacitors 15 and 16. At this center tap point 18, one of the ends or connecting conductor 14 of the inductor coil 13 is connected. Between the emitter of the first power semiconductor 25 and the collector of the second power semiconductor 26, a further point 19 is present. At this center tap point 19, the second end and the second terminal conductor 17 of the inductor coil 13 is connected. In the illustrated case, the power semiconductors 25 and 26 are designed as bipolar transistors. In particular, however, also embodiments with related power semiconductors are conceivable, such as e.g. IGBTs (Insulated gate bipolar transistors), MOS-FET transistors, thyristors, GTO's and triacs.

Im Inverter 8 sind des weiteren Sensoren für die Temperaturüberwachung der Leistungselektronik und des Gefässes 6 sowie Vorrichtungen zur Messung des Stromes durch den Induktor 13 und der aktuellen Leistung des Induktors 5 integriert (nicht dargestellt). Die durch diese Überwachungsvorrichtungen gelieferten Resultate werden über die Messleitungen 11 zum Mikroprozessor 10 zurückgeführt. Diese Messleitungen 11 sind Signalleitungen, welche den Inverter 8 mit dem Mikroprozessor 10 verbinden und die so ausgeführt sind, dass entweder digitale oder analoge Messwerte aus dem Inverter 8 in den Mikroprozessor 10 übertragen werden können. Diese Signalleitungen 11 können dedizierte Drahtleitungen und einen digitalen Steuerbus umfassen.In the inverter 8 further sensors for the temperature monitoring of the power electronics and the vessel 6 and devices for measuring the current through the inductor 13 and the current performance of the inductor 5 are integrated (not shown). The results provided by these monitoring devices are fed back to the microprocessor 10 via the measuring leads 11. These measuring lines 11 are signal lines which connect the inverter 8 to the microprocessor 10 and which are designed so that either digital or analog measured values from the inverter 8 in the Microprocessor 10 can be transmitted. These signal lines 11 may include dedicated wire lines and a digital control bus.

Die Versorgung des jeweiligen Induktors 13 mit Energie erfolgt impulsartig und periodisch. Dies bedeutet, dass Energie dem Induktor 13 in Form von Impulsen zugeführt wird und dass diese Impulse innerhalb aufeinander folgenden bzw. sich wiederholenden Perioden bzw. Zeitfenstern liegen. Diese Situation ist in Fig. 3, 4 und 5 anhand von Diagrammen dargestellt. Auf der X-Achse des jeweiligen Diagramms ist die Zeit t aufgetragen. Die einzelnen Perioden bzw. Zeitfenster der Energiezuleitung zu den Induktoren 13 sind in allen drei übereinander liegenden Fig. 3 bis 5 mit Hilfe von zur X-Achse senkrecht stehenden und übereinander liegenden Linien L voneinander getrennt. Eine Periode bzw. ein Zeitfenster wird im Nachstehenden daher mit LL bezeichnet.The supply of the respective inductor 13 with energy takes place in pulses and periodically. This means that energy is supplied to the inductor 13 in the form of pulses and that these pulses are within successive or repetitive periods or time windows. This situation is in Fig. 3, 4 and 5 illustrated by diagrams. The time t is plotted on the X-axis of the respective diagram. The individual periods or time windows of the energy supply to the inductors 13 are in all three superimposed Fig. 3 to 5 separated from each other by means of perpendicular to the X-axis and superimposed lines L. A period or a time window is therefore designated LL in the following.

Die Zeitfenster LL weisen für alle Induktoren 13 dieselbe Länge bzw. Breite auf. Ausserdem liegen die Anfänge bzw. Enden der Zeitfenster praktisch in demselben Zeitpunkt L. Die Länge bzw. Breite der sich wiederholenden Zeitfenster LL wird als Tmax (Fig. 4) bezeichnet. Die Länge des Zeitfensters Tmax ist bei allen Kochstellen 3 gleich, sodass die Wiederholungsfrequenz der Speisung der benachbarten Induktoren 13 mit Energie bei allen Induktoren 13 praktisch dieselbe ist. Die Tmax ist für alle Induktoren 13 ausserdem auch konstant, d.h. unveränderlich, und zudem noch so gewählt, dass die Länge von Tmax der Periode der Frequenz von etwa 22kHz entspricht. Diese Frequenz entspricht der Arbeitsfrequenz von etwa 22kHz des Induktor-Schwingkreises im Inverter 8. Die Induktoren 13 aller Kochstellen 3 werden in dieser Häufigkeit bzw. Frequenz mit den Energieimpulsen versorgt.The time slots LL have the same length or width for all inductors 13. In addition, the beginnings and ends of the time slots are practically at the same time L. The length or width of the repetitive time slots LL is expressed as Tmax ( Fig. 4 ) designated. The length of the time window Tmax is the same for all cooking zones 3, so that the repetition frequency of feeding the neighboring inductors 13 with energy is practically the same for all inductors 13. The Tmax is also constant for all inductors 13, ie invariable, and moreover chosen so that the length of Tmax corresponds to the period of the frequency of about 22kHz. This frequency corresponds to the operating frequency of about 22 kHz of the inductor resonant circuit in the inverter 8. The inductors 13 of all cooking zones 3 are supplied in this frequency or frequency with the energy pulses.

Die Verwendung der genannten Arbeitsfrequenz bzw. der genannten Häufigkeit der impulsartigen Zuführung von Energie zu den Induktoren 13 schafft Voraussetzungen dafür, dass der jeweilige Inverter 8 die diesem zugeordnete Induktionsspule 13 mit maximaler Menge von Energie versorgen kann. Dies deswegen, weil der praktisch grösstmögliche und noch zulässige elektrische Strom bei der genannten Arbeitsfrequenz durch den Induktor-Schwingkreis fliessen kann. Bei diesem Verfahren werden störende Pfeiftöne deswegen eliminiert, weil alle Induktoren 13 in einem Kochherd mit derselben Häufigkeit gesteuert werden. Die Taktgeneratoren der einzelnen Energiequellen 4, welche einen der Bestandteile des Mikroprozessors 10 darstellen können, arbeiten somit auf im wesentlichen derselben Frequenz. Sie brauchen jedoch nicht miteinander synchronisiert zu sein. Denn wenn es dennoch Differenzfrequenzen zwischen zwei benachbarten Induktoren 13 geben sollte, dann würde die Frequenz dieser Töne im Bereich von etwa 2Hz liegen. Solche Töne liegen unterhalb der Hörschwelle des Menschen, sodass man solche Töne gar nicht hören würde.The use of said operating frequency or the stated frequency of the pulse-like supply of energy to the inductors 13 creates Conditions for the respective inverter 8 can supply the associated induction coil 13 with maximum amount of energy. This is because the practically greatest possible and still permissible electric current can flow through the inductor resonant circuit at the said operating frequency. In this method, annoying whistling sounds are eliminated because all the inductors 13 in a cooking range are controlled with the same frequency. The clock generators of the individual energy sources 4, which can represent one of the components of the microprocessor 10, thus operate at substantially the same frequency. But you do not need to be in sync with each other. For if there were still difference frequencies between two adjacent inductors 13, then the frequency of these tones would be in the range of about 2Hz. Such sounds are below the hearing threshold of humans, so that one would not hear such sounds.

Die eigentliche Steuerung der Leistung der Induktoren 13 erfolgt, wie dies bereits erwähnt wurde, durch eine impulsartige Leitung von Strom I durch die Induktoren 13 der Kochstellen 3 innerhalb der Zeitfenster LL. Die an den jeweiligen Induktor 13 abgegebene elektrische Leistung ist dabei nicht nur von der Grösse des durch die Spule 13 fliessenden Stromes I bestimmt sondern auch durch jene Zeitspanne, während welcher dieser Strom I durch die Spule 13 fliesst. Die Zeitspanne, während welcher der Strom I durch den Induktor 13 fliesst, ist praktisch identisch mit jener Zeitspanne, während welcher der betreffende steuerbare Schalter 25 bzw. 26 im Inverter 8 leitend ist. Deswegen kann der zeitliche Verlauf des Stromes I durch den Induktor 13 im Zusammenhang mit dem zeitlichen Verlauf jener Impulse bzw. jener Spannungen A und B beschrieben werden, welche das Öffnen der Schaltelemente 25 und 26 steuern. Auf der Y-Achse der Diagramme in Fig. 3 bis 5 ist die Grösse jener Spannung US ausgetragen, welche das Öffnen der Transistoren 25 und 26 steuert. Unter anderem auch die Parameter des Inverters 8 bestimmen dann, wie gross der Strom I ist, welcher während der Zeitspanne TA und TB durch den Induktor 13 fliesst, nachdem der betreffende Schalter 25 bzw. 26 leitend gemacht worden ist. Der Verlauf der dem Induktor 13 zugeführten Leistung ist in Fig. 5 mit der Linie W dargestellt. In Fig. 3 und 4 könnten entsprechende Linien W eingezeichnet sein. Der Strom I kann während der Zeitspannen TA und TB im vorliegenden Fall einen konstanten Wert haben.The actual control of the power of the inductors 13 is, as already mentioned, by a pulse-like conduction of current I through the inductors 13 of the cooking zones 3 within the time window LL. The electric power delivered to the respective inductor 13 is determined not only by the magnitude of the current I flowing through the coil 13, but also by that period of time during which this current I flows through the coil 13. The period of time during which the current I flows through the inductor 13 is virtually identical to that period during which the relevant controllable switch 25 or 26 in the inverter 8 is conducting. Therefore, the timing of the current I through the inductor 13 can be described in connection with the timing of those pulses and those voltages A and B, which control the opening of the switching elements 25 and 26. On the y-axis of the diagrams in Fig. 3 to 5 is the size of that voltage US discharged, which is the opening of the Transistors 25 and 26 controls. Among other things, the parameters of the inverter 8 then determine how large the current I is, which flows through the inductor 13 during the time period TA and TB, after the relevant switch 25 or 26 has been made conductive. The course of the inductor 13 supplied power is in Fig. 5 represented by the line W. In 3 and 4 appropriate lines W could be located. The current I may have a constant value during the periods TA and TB in the present case.

Der Impuls A in Fig. 3 bis 5 zeigt den zeitlichen Verlauf jener Steuerspannung US während einem Zeitfenster LL, welche über die Leitung 7A an die Basis des erstens Transistors 25 angelegt wird. Der Impuls B in Fig. 3 bis 5, welcher auf den ersten Impuls A folgt, zeigt den zeitlichen Verlauf jener Steuerspannung US während einem Zeitfenster LL, welche über die Leitung 7B an die Basis des zweiten Transistors 26 angelegt wird. Die Ansteuerungssignale A und B sind praktisch Rechtecksignale. Die Grösse der Steuerspannungen US liegt zwischen 0 Volt und einer maximalen zweckmässigen Ansteuerspannung US, welche für den Betrieb der Schalter 25 und 26 zweckmässig ist. Diese Steuerimpulse A und B haben dieselbe Polarität.The impulse A in Fig. 3 to 5 shows the time course of that control voltage US during a time window LL, which is applied via the line 7A to the base of the first transistor 25. The momentum B in Fig. 3 to 5 , which follows the first pulse A, shows the time profile of that control voltage US during a time window LL, which is applied via the line 7B to the base of the second transistor 26. The drive signals A and B are practically rectangular signals. The size of the control voltages US is between 0 volts and a maximum appropriate drive voltage US, which is useful for the operation of the switches 25 and 26. These control pulses A and B have the same polarity.

Die Zeitdauern TA und TB der Steuersignale A und B, welche während einem Zeitfenster LL bzw. Tmax dem Inverter 8 zugeführt werden, bleiben sich im vorliegenden Verfahren einander immer gleich, und zwar unabhängig von der absoluten Länge der Zeitdauer TA und TB. D.h., wenn die Länge eines der Impulse A bzw. B um einen bestimmten Betrag verlängert oder verkürzt wird, dann wird die Länge des anderen Steuerimpulses B bzw. A um denselben Betrag ebenfalls verlängert oder verkürzt. Dabei gilt, dass dem Induktor um so mehr elektrische Energie zugeführt wird, je länger die Zeiten TA und TB der Impulse A und B sind, und umgekehrt.The durations TA and TB of the control signals A and B, which are supplied to the inverter 8 during a time window LL and Tmax respectively, always remain the same in the present method, irrespective of the absolute length of the time duration TA and TB. That is, if the length of one of the pulses A and B is lengthened or shortened by a certain amount, then the length of the other control pulse B or A is also extended or shortened by the same amount. In this case, the longer the times TA and TB of the pulses A and B are, the more the electrical energy is supplied to the inductor, and vice versa.

Zweckmässigerweise beginnt die Generierung des ersten Steuerimpulses A immer am Anfang oder kurz nach dem Anfang des jeweiligen Zeitfensters LL bzw. der jeweiligen Periode Tmax, d.h. im Zeitpunkt 0 des Zeitfensters LL oder kurz danach, und zwar unabhängig davon, wie lang die Impulse A und B dauern. Der Steuerimpuls B wird erst nach dem Impuls A generiert, und zwar erst nach dem Ablauf einer kurzen Zeitspanne, welche zwischen diesen zwei Impulsen liegt und welche mit den Entladezeiten in den Schaltern 25 und 26 zusammenhängt.Expediently, the generation of the first control pulse A always begins at the beginning or shortly after the beginning of the respective time window LL or the respective period Tmax, i. at the time 0 of the time slot LL or shortly thereafter, regardless of how long the pulses A and B last. The control pulse B is generated after the pulse A, and only after the lapse of a short period, which is between these two pulses and which is related to the discharge times in the switches 25 and 26.

Fig. 3 zeigt die Länge TA und TB der Steuerimpulse A und B für die maximale Speisung des Induktors 13 mit Energie. Fig. 5 zeigt die Länge TA und TB der Steuerimpulse A und B für eine minimale Speisung des Induktors 13 mit Energie. Fig. 4 zeigt die Länge TA und TB der Steuerimpulse A und B für einen mittleren Leistungsbereich des Induktors 13. Jede der Zeitdauern TA bzw. TB ist kleiner als Tmax, welche der Länge des Zeitfensters LL entspricht. Die Summe S aus den beiden Zeitdauern TA und TB ist immer kleiner als Tmax. Fig. 3 shows the length TA and TB of the control pulses A and B for the maximum supply of the inductor 13 with energy. Fig. 5 shows the length TA and TB of the control pulses A and B for a minimum supply of the inductor 13 with energy. Fig. 4 shows the length TA and TB of the control pulses A and B for a middle power range of the inductor 13. Each of the durations TA and TB is smaller than Tmax, which corresponds to the length of the time window LL. The sum S of the two durations TA and TB is always smaller than Tmax.

Wenn die Summe S aus TA und TB kleiner ist als Tmax (Fig. 4 und 5), dann ergibt sich daraus eine Differenzzeit Tdif zwischen dem Ende der genannten Summe S, d.h. zwischen dem Ende des zweiten Steuerimpulses B und der Tmax. (Fig. 4). Während dieser Tdif fliesst kein Strom durch den Induktor 13. Durch eine Variierung des Verhältnisses zwischen der Länge der Summe S und der Länge der Tdif kann die Leistung des Induktors 13 variiert werden. Je höher die an die Spule 13 abgegeben Leistung sein soll, um so breiter werden die Steuerimpulse A und B gemacht und um so kürzer wird die Tdif, bis die Tdif bei der maximalen Leistung des Induktors 13 beinahe 0 ist (Fig. 3). In diesem Fall gleicht die Summe S der Zeitintervalle TA + TB praktisch der Tmax bzw. der Länge des Zeitfensters LL.If the sum S of TA and TB is smaller than Tmax ( 4 and 5 ), this results in a difference time Tdif between the end of said sum S, ie between the end of the second control pulse B and the Tmax. ( Fig. 4 ). During this Tdif no current flows through the inductor 13. By varying the ratio between the length of the sum S and the length of the Tdif, the power of the inductor 13 can be varied. The higher the power output to the coil 13, the wider the control pulses A and B are made, and the shorter the Tdif becomes until the Tdif at the maximum power of the inductor 13 is almost 0 ( Fig. 3 ). In this case, the sum S of the time intervals TA + TB practically equals the Tmax or the length of the time window LL.

Der erste Steuerimpuls A macht den Transistor 26 leitend und der Strom I fliesst in diesem Fall von der Minusklemme DC- durch diesen Transistor 26, den zwischen den Transistoren 25 und 26 liegenden Mittelabgriff 19, die Spule 13, den zwischen den Kondensatoren 15 und 16 liegenden Mittelabgriff 18 und die Kondensatoren 15 und 16 zur Plusklemme DC+ der Gleichspannungsquelle DC. Mit einer bestimmten und erforderlichen Verzögerung gelangt ein Impuls B über die Leitung 7B zur Basis des anderen Transistors 25 und macht diesen leitend. Der Strom I fliesst jetzt von der Plusklemme DC+ durch diesen Transistor 25, den Transistormittelabgriff 19, die Spule 13, jetzt allerdings in der entgegengesetzten Richtung, den Kondensatormittelabgriff 18 und die Kondensatoren 15 und 16 zur Minusklemme DC- der Gleichspannungsquelle DC.The first control pulse A makes the transistor 26 conductive and the current I in this case flows from the negative terminal DC- through this transistor 26, the intermediate tap between the transistors 25 and 26 19, the coil 13, lying between the capacitors 15 and 16 Center tap 18 and the capacitors 15 and 16 to the positive terminal DC + the DC voltage source DC. With a certain and required delay, a pulse B passes via the line 7B to the base of the other transistor 25 and makes it conductive. The current I now flows from the positive terminal DC + through this transistor 25, the transistor center tap 19, the coil 13, but now in the opposite direction, the capacitor center tap 18 and the capacitors 15 and 16 to the minus terminal DC- of the DC voltage source DC.

Die Zeitdauer TA bzw. TB könnte für die Leistungsregulierung praktisch gegen Null gehen. Allerdings ist aus technischen Gründen diese Wahl nicht sehr sinnvoll. Für die Regulierung der Leistung des Induktors 13 im Bereich der minimalen Leistungen wird eine Summe S aus TA und TB bevorzugt, welche der Periodenlänge Tmin einer Frequenz entspricht.The time period TA or TB could be virtually zero for power regulation. However, for technical reasons, this choice does not make much sense. For the regulation of the power of the inductor 13 in the range of the minimum powers, a sum S of TA and TB is preferred, which corresponds to the period length Tmin of a frequency.

Das vorliegende Verfahren bietet neben dem Vorteil, dass die Leistung in jeder Kochstelle 3 individuell geregelt werden kann, auch den wichtigen Vorteil, dass das Zuleitungsnetz für die elektrische Energie nicht pulsartig sondern kontinuierlich belastet wird. Dies deswegen, weil die TA und TB gleichzeitig und immer um denselben Betrag verlängert oder verkürzt werden. Dies ist deswegen wichtig, weil die Kochstellen 3 bei ihren Spitzenleistungen mehrere Ampere Strom dem Versorgungsnetz normalerweise entnehmen.The present method offers not only the advantage that the power in each hob 3 can be controlled individually, but also the important advantage that the supply network for the electrical energy is not pulsed but continuously charged. This is because the TA and TB are extended and shortened simultaneously and always by the same amount. This is important because the cooking stations 3 usually draw several amperes of power from the supply network at their peak outputs.

Das vorliegende Verfahren kann auch in geregelter Weise durchgeführt werden, indem Messsignale über die Messleitungen 11 dem Mikroprozessor 10 zugeleitet werden. Der Mikroprozessor 10 steuert in diesem Fall basierend auf Messwerten aus den Messleitungen 11 die Grösse des Induktorstromes I, seinen Null-Durchgang, den Zeitpunkt für die Schaltung der Steuerleitungen 7A und 7B usw. Auch der gesamte Garvorgang kann auf diese Weise überwacht und geregelt werden. So erfordert ein grosser Kochtopf 6 gefüllt mit Wasser eine andere Art wie von Betrieb der Kochstelle 3 als beispielsweise eine Bratpfanne mit einem Spiegelei. Insbesondere darf kein Garvorgang gestartet werden, wenn sich andere metallische Gegenstände wie z.B. eine Gabel oder ein Kochlöffel auf dem Herd befinden.The present method can also be carried out in a controlled manner by measuring signals via the measuring lines 11 to the microprocessor 10th be forwarded. In this case, the microprocessor 10 controls the magnitude of the inductor current I, its zero crossing, the timing for the switching of the control lines 7A and 7B, etc., based on measured values from the measuring lines 11. The entire cooking process can also be monitored and regulated in this way. Thus, a large saucepan 6 filled with water requires a different kind of operation than the cooking zone 3, for example a frying pan with a fried egg. In particular, no cooking process may be started when other metallic objects such as a fork or a wooden spoon are on the stove.

Eine Erweiterung des vorliegenden Verfahrens besteht darin, dass über Messimpulse die Art des Gefässes 6 auf der Herdplatte 2 laufend detektiert wird. Zur Feststellung der Güte des Gefässes 6 werden den Steuerimpulsen A und B für die Schalter 25 und 26 Impulse (nicht dargestellt) vorgelagert, deren Länge kleiner ist als die Länge der Steuerimpulse A und B. Diese Messimpulse gelangen im für die Steuerimpulse A und B beschriebenen Weg bis zum Induktor 13 der Herdplatte 2, auf welcher das Kochgefäss 6 ruht. Entsprechend der Beschaffenheit dieses Kochgefässes 6 werden die Messimpulse beeinflusst und eine solche Antwort gelangt dann über eine der Messleitungen 11 bis zum Mikroprozessor 10, welcher unter anderem die Arbeitsweise des Inverters 8 steuert.An extension of the present method is that the nature of the vessel 6 is continuously detected on the stove plate 2 via measuring pulses. In order to determine the quality of the vessel 6, the control pulses A and B for the switches 25 and 26 are preceded by pulses (not shown) whose length is smaller than the length of the control pulses A and B. These measuring pulses arrive in the manner described for the control pulses A and B. Way to the inductor 13 of the hob plate 2, on which the cooking vessel 6 rests. According to the nature of this cooking vessel 6, the measuring pulses are influenced and such a response then passes via one of the measuring lines 11 to the microprocessor 10, which among other things controls the operation of the inverter 8.

In Fig. 8 sind zwei Diagramme betreffend diesen Sachverhalt übereinander wiedergegeben. Auf der y-Achse des oben liegenden Diagramms ist die Steuerspannung US für die Schalter 25 bzw. 26 ausgetragen. Auf der y-Achse des unten liegenden Diagramms ist der Strom IS durch den Induktor 13 ausgetragen. Aus Fig. 8 ist ersichtlich, dass es eine Phasenverschiebung zwischen dem Spulenstrom IS und der Steuerspannung US geben kann. Die Grösse dieser Phasenverschiebung ist von der Art bzw. Güte des Gefässes bzw. des sich auf der Herdplatte 2 befindlichen Gegenstandes abhängig. Die Grösse der Phasenverschiebung wird über die Zeitdifferenz DT zwischen dem Nulldurchgang der Steuerspannung US und dem Nulldurchgang des Stromes IS durch den Induktor 13 ermittelt. Je kleiner diese Zeitdifferenz DT ist, um so besser ist die Güte des Gefässes 6, sodass ein Garvorgang durch den Inverter 8 gestartet werden kann. Wenn Zeitdifferenz DT jedoch einen in der Regelungsvorrichtung 9 einstellbaren Mindest-Grenzwert für die Güte überschreitet, dann ist ein Garvorgang nicht mehr wirksam möglich. Dies beispielsweise deswegen, weil das Gefäss 6 aus einem Material ist, welches für die Induktionserwärmung nicht geeigent ist. In einem solchen Fall nimmt die Regelvorrichtung 9 den Inverter 8 und somit auch Platte 5 gar nicht in Betrieb oder sie schaltet den Inverter 8 und somit auch diese Kochstelle 3 aus.In Fig. 8 two diagrams relating to this issue are superimposed. On the y-axis of the above diagram, the control voltage US for the switches 25 and 26 is discharged. On the y-axis of the diagram below, the current IS is discharged through the inductor 13. Out Fig. 8 It can be seen that there can be a phase shift between the coil current IS and the control voltage US. The size of this phase shift depends on the type or quality of the vessel or of the object located on the stove top 2 dependent. The magnitude of the phase shift is determined by the inductor 13 over the time difference DT between the zero crossing of the control voltage US and the zero crossing of the current IS. The smaller this time difference DT, the better the quality of the vessel 6, so that a cooking process can be started by the inverter 8. However, if the time difference DT exceeds a minimum limit value for the quality that can be set in the control device 9, then a cooking process is no longer effectively possible. This is because, for example, the vessel 6 is made of a material which is not suitable for induction heating. In such a case, the control device 9 takes the inverter 8 and thus also plate 5 is not in operation or it turns off the inverter 8 and thus also this hotplate 3 off.

Zu diesen Auswertungszwecken ist eine Sammlung von entsprechenden Schrittantworten im Speicher des Mikroprozessors 10 gespeichert. Abhängig von den Vorgaben des Bedienteiles 9, der Beschaffenheit des Gefässes 6 und des Gargutes wird durch das Verfahren eine eigens im Speicher des Mikroprozessors vorgegebene zeitlich abhängig geregelte Leistungsregelung des Garvorganges durchgeführt. Insbesondere ist für entsprechende Kombinationen von Gefäss 6 und Gargut eine Folge von zeitlich änderbaren Zeitintervallen TA resp. TB im Speicher des Mikroprozessors gespeichert. So können auch Vorgänge wie z.B. eine grosse Heizleistung für das Anbraten mit anschliessendem Schmoren individuell an das Gargut durch den Mikroprozessor angepasst und geregelt werden.For these evaluation purposes, a collection of corresponding step responses is stored in the memory of the microprocessor 10. Depending on the specifications of the control unit 9, the nature of the vessel 6 and the food to be cooked by the method a specific time-dependent regulated power control of the cooking process is performed in the memory of the microprocessor. In particular, for corresponding combinations of vessel 6 and food to be cooked, a sequence of time-changeable time intervals TA resp. TB stored in the memory of the microprocessor. Thus, processes such as e.g. a large heating power for the searing with subsequent braising individually adapted to the food by the microprocessor and regulated.

Die Informationen über das Gargut, den Garfortschritt usw. werden über die Messleitungen 11 an den Mikroprozessor 10 geliefert. Dabei werden auch externe Sensoren eingesetzt wie z.B. ein externer Temperatursensor 27, welcher in das Gargut eingesteckt sein kann und welcher so den Status des Garvorganges über eine entsprechende Messleitung 11 an den Mikroprozessor 10 meldet.The information about the food to be cooked, the cooking progress, etc. are supplied to the microprocessor 10 via the measuring lines 11. In this case, external sensors are used, such as an external temperature sensor 27, which can be plugged into the food and which thus the status of the Cooking process via a corresponding measuring line 11 to the microprocessor 10 reports.

Über die Diagnoseschnittstelle 24 können die relevanten Parameter des Verfahrens für die unterschiedlichen Ausprägungen der Gefässe und des Gargutes jederzeit verändert oder erweitert werden. Mit dieser Schnittstelle 24 ist es möglich, das Verfahren von einem Fremdsystem, wie beispielsweise von einer übergeordneten Steuervorrichtung, von einem externen Diagnosegerät oder von einem Arbeitsplatzrechner zu diagnostizieren, zu steuern usw. Fig. 6 zeigt eine Ausführungsform einer Speisungsvorrichtung 30 für den Induktor 13, wenn die Speisung desselben mit Energie aus einem dreiphasigen Versorgungsnetz erfolgen soll. Die Speisungsvorrichtung 30 umfasst unter anderem drei Phasenanschlüsse L1, L2 und L3 an das Versorgungsnetz. An die drei Phasenanschlüsse L1, L2 und L3 ist ein Gleichrichter 28 angeschlossen, welcher als ein Dreiphasen-Brückengleichrichter ausgeführt ist. Dieser wandelt die Wechselspannung aus dem Versorgungsnetz in eine Gleichspannung, welche an den Ausgangsklemmen DC+ und DC- dieser Speisungsvorrichtung 30 erscheinen kann. Zwischen den Ausgangsklemmen DC+ und DC- des Dreiphasen-Brückengleichrichters 28 befindet sich ein Glättungskondensator C. An den Ausgangsklemmen DC+ und DC- des Brückengleichrichters 28 wird die Gleichspannung für den Induktor 13 abgegriffen und durch den LC-Schwingkreis bzw. durch die Brücke im Inverter 8 dem Induktor 13 zugeführt.About the diagnostic interface 24, the relevant parameters of the process for the different forms of the vessels and the food can be changed or extended at any time. With this interface 24, it is possible to diagnose, control, and so on the process from a foreign system, such as from a parent controller, from an external diagnostic device or from a workstation. Fig. 6 shows an embodiment of a supply device 30 for the inductor 13, when the supply of the same is to be made with energy from a three-phase supply network. The feeding device 30 includes, inter alia, three phase terminals L1, L2 and L3 to the utility grid. Connected to the three phase terminals L1, L2 and L3 is a rectifier 28, which is implemented as a three-phase bridge rectifier. This converter converts the AC voltage from the supply network into a DC voltage, which can appear at the output terminals DC + and DC- of this supply device 30. Between the output terminals DC + and DC- of the three-phase bridge rectifier 28 is a smoothing capacitor C. At the output terminals DC + and DC- of the bridge rectifier 28, the DC voltage for the inductor 13 is tapped and by the LC resonant circuit or through the bridge in the inverter. 8 fed to the inductor 13.

Die Speisungsvorrichtung 30 kann auch zur Begrenzung der durch die vorliegende Einrichtung dem Netz entnommenen Leistung eingerichtet sein. Diese Leistungsbegrenzung ist notwendig, um den Verbrauch des Kochherd an Energie im Rahmen der bei der Gebäudeinstallation zulässigen Energieentnahme halten zu können.The feed device 30 may also be configured to limit the power drawn by the present device from the mains. This power limitation is necessary in order to keep the consumption of the stove to energy in the context of the permitted during the building installation energy extraction.

Dazu ist, wie in Fig. 6 dargestellt, an einem der Phasenleiter L1 eine Strom-Messvorrichtung 29 eingeschaltet, welche dem Brückengleichrichter 28 vorgeschaltet ist. Der Ausgang der Strom-Messvorrichtung 29 ist an einen der Eingänge der Regelungsvorrichtung 9 angeschlossen. Für eine vorgegebene Anschlussleistung sind entsprechende maximal zulässige Stromstärken in der Regelungsvorrichtung 9 als Regelungsparameter einstellbar. Die Regelungsvorrichtung 9 regelt die maximale Leistungsaufnahme des Induktors 13 derart, dass die von der Gebäudeinstallation maximal bezogene Leistung dennoch einen zulässigen Wert nicht überschreitet.This is how in Fig. 6 shown, on one of the phase conductors L1, a current measuring device 29 is turned on, which is connected upstream of the bridge rectifier 28. The output of the current measuring device 29 is connected to one of the inputs of the control device 9. For a given connection power corresponding maximum permissible currents are adjustable in the control device 9 as a control parameter. The control device 9 regulates the maximum power consumption of the inductor 13 in such a way that the maximum power drawn by the building installation nevertheless does not exceed a permissible value.

Die vorliegende Einrichtung kann auch aus einem einphasigen Netz mit Energie versorgt werden. Wie dies in Fig. 7 gezeigt ist, verfügt die Speisevorrichtung 31 über einen einphasigen Brückengleichrichter 32, welcher über Anschlüsse N und L an das einphasige Versorgungsnetz anschliessbar ist. Die Strom-Messvorrichtung 29 befindet sich in diesem Fall im Anschlussleiter L.The present device can also be powered from a single-phase network. Like this in Fig. 7 is shown, the feed device 31 has a single-phase bridge rectifier 32, which can be connected via terminals N and L to the single-phase supply network. The current measuring device 29 is located in the connection conductor L in this case.

Das erfindungsgemässe Verfahren bietet unter anderem die Möglichkeit, dass die Grösse der Leistung der einzelnen Kochstellen 3 in einem Induktionskochherd 1 gleichzeitig und individuell gesteuert werden kann, ohne dass dabei hörbare und normalerweise durch Interferenzen zwischen benachbarten Induktoren 13 verursachten Geräusche, beispielsweise Pfeiftöne, entstehen. Folglich können nebeneinander angeordnete Kochstellen 3 in einem Induktionskochherd 1 mit unterschiedlichen Leistungen betrieben werden, ohne dass dabei die erwähnten Geräusche entstehen. Ferner bietet das vorliegende Verfahren unter anderem die Vorteile, dass das Zuleitungsnetz für elektrische Energie ohne Stromstösse belastet wird und dass der Garvorgang gleichmässig erfolgt. Das Verfahren kann auch in dem Fall angewendet werden, wenn als Speisespannung für den Inverter 8 eine mehrphasige Wechselspannung dienen soll.The method according to the invention offers, inter alia, the possibility that the magnitude of the power of the individual cooking zones 3 in an induction cooker 1 can be controlled simultaneously and individually without generating any audible noise, for example whistling sounds, normally caused by interferences between adjacent inductors 13. Consequently, co-located cooking zones 3 can be operated in an induction cooker 1 with different powers, without causing the mentioned noise. Furthermore, the present method provides, inter alia, the advantages that the supply network for electrical energy is charged without power surges and that the cooking process is uniform. The method can also be applied in the case when as Supply voltage for the inverter 8 is intended to serve a multiphase AC voltage.

Claims (6)

  1. A method for regulating the output of an induction cooking stove having a plurality of cooking positions (3), with each of these cooking position (3) having an inductor (13), characterized in that the method is configured in such a way that the network of supply lines for supplying the cooking positions (3) is continually charged with electrical energy, with the individual inductors (13) being supplied with energy by autonomous sources (4), i.e., sources that are discrete, separated from one another, connected to the respective inductor (13), and associated only with said inductor, during consecutive periods (LL), with the duration (Tmax) of the periods (LL) of actuation being equally long for all inductors (13) and with the energy being supplied to the respective inductor (13) as a sequence of control impulses (A, B) that always have the same length within a period (LL), with a first control impulse (A) having a first length (TA) generating a first electrical current through the inductor (13) and a second control impulse (B) having a second length (TB) that is equal to the first length (TA) generating a second electrical current through the inductor (13) but in the opposite direction of the first electrical current, and in that the amount of energy supplied to the respective inductor (13) during a period is controlled by changes of equal size to the length of the control impulses (A, B).
  2. The method according to Claim 1, characterized in that the energy is supplied to the respective inductor (13) as a pair of equally long impulses (A, B) within a period.
  3. The method according to Claim 1, characterized in that the changes to the length of the two impulses (A, B) of the impulse pair are of equal size.
  4. The method according to Claim 1, characterized in that, for all outputs of the inductor (13), the first control impulse (A) begins to be generated subsequently to the beginning of the period (Tmax).
  5. The method according to Claim 1, characterized in that the length (Tmax) of the period of actuation of the inductor (13) corresponds to the frequency at which the inductor (13) is able to operate at its maximum output and in that this duration (Tmax) remains unchanged for all output levels of the inductor (13).
  6. The method according to Claim 2, characterized in that the length (TA; TB) of the respective impulse (A; B) that the inverter (8) feeding energy to the inductor (13) is able to control during one period (Tmax) is shorter than the period (Tmax).
EP04405263A 2003-06-30 2004-04-29 Method and device of power control of induction cooktops Expired - Lifetime EP1494505B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH01151/03A CH696649A5 (en) 2003-06-30 2003-06-30 Method and apparatus for power control of induction cookers.
CH11512003 2003-06-30

Publications (3)

Publication Number Publication Date
EP1494505A2 EP1494505A2 (en) 2005-01-05
EP1494505A3 EP1494505A3 (en) 2006-05-03
EP1494505B1 true EP1494505B1 (en) 2010-11-24

Family

ID=33426275

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04405263A Expired - Lifetime EP1494505B1 (en) 2003-06-30 2004-04-29 Method and device of power control of induction cooktops

Country Status (5)

Country Link
EP (1) EP1494505B1 (en)
AT (1) ATE489830T1 (en)
CH (1) CH696649A5 (en)
DE (1) DE502004011915D1 (en)
ES (1) ES2356737T3 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2911472B1 (en) 2013-12-20 2020-03-11 BSH Hausgeräte GmbH Cooking appliance, in particular cooking hob device, with a plurality of inverters

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006058874A1 (en) * 2006-12-06 2008-06-19 E.G.O. Elektro-Gerätebau GmbH Method for controlling induction heating devices in an electric cooking appliance
DE102007050341A1 (en) * 2007-10-12 2009-04-23 E.G.O. Commercial Electronics Ag Induction module, arrangement of several induction modules and method for setting up such an induction module
ES2622142T3 (en) 2008-10-08 2017-07-05 Whirlpool Corporation A method for controlling a static power conversion unit and an induction heating system for cooking appliances using said method
US9307581B2 (en) 2011-01-11 2016-04-05 Elatronic Ag Induction heating system with self regulating power control

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH664660A5 (en) * 1983-05-07 1988-03-15 Barmag Barmer Maschf Inductive heater for ferromagnetic material
JP2530812B2 (en) * 1985-12-12 1996-09-04 富士電機株式会社 High frequency induction heating device
US5004881A (en) * 1989-11-22 1991-04-02 Goldstar Co., Ltd. Method and circuit for controlling power level in the electromagnetic induction cooker

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2911472B1 (en) 2013-12-20 2020-03-11 BSH Hausgeräte GmbH Cooking appliance, in particular cooking hob device, with a plurality of inverters
EP2911472B2 (en) † 2013-12-20 2022-11-09 BSH Hausgeräte GmbH Cooking appliance, in particular cooking hob device, with a plurality of inverters

Also Published As

Publication number Publication date
CH696649A5 (en) 2007-08-31
ES2356737T3 (en) 2011-04-12
EP1494505A2 (en) 2005-01-05
DE502004011915D1 (en) 2011-01-05
EP1494505A3 (en) 2006-05-03
ATE489830T1 (en) 2010-12-15

Similar Documents

Publication Publication Date Title
EP1935213B1 (en) Method for operating an induction heating device
DE3612707C2 (en)
DE602005003310T2 (en) Inverter circuit for induction heating, cooking appliance with such a circuit and operating method
WO2010069616A1 (en) Cook-top having at least three heating zones
DE3332990A1 (en) ELECTROMAGNETIC INDUCTION HEATING DEVICE
EP2034800A1 (en) Cooking device switch
WO2011135470A1 (en) Hob device
EP2506663A1 (en) Cooking device
EP1494505B1 (en) Method and device of power control of induction cooktops
WO2016071803A1 (en) Cooking appliance
EP2506665B1 (en) Cooking device
EP2469972B1 (en) Cooking device and method of controlling the cooking device which diminish in an iterative manner a flicker characteristic.
EP2506673B1 (en) Induction cooktop
EP2692202B1 (en) Induction heating device
EP0442139A2 (en) Method and device for steering the power of at least one consumer
EP2469971B1 (en) Cooking device
EP3641497B1 (en) Cooking device
EP0153488A1 (en) Method for producing, injecting and transmitting signals in an electric low voltage distribution network
DE102012201237A1 (en) Household appliance device, particularly cook top apparatus, for use in household appliance, has two power converters operated in operating mode, where control unit is provided to control operating portion characteristic
DE19734107A1 (en) Dimmer
DE10329683A1 (en) Digital interface with potentiometer
EP2380394B1 (en) Induction cooktop having at least one power inverter
EP2945461B1 (en) Cooking device
DE102012206940A1 (en) Induction heating device i.e. induction hob device, for use in induction oven, has control unit simultaneously adjusting resonance capacitor of resonance unit and attenuation capacitor depending on operational parameter
EP2590475B1 (en) Induction heating device

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

17P Request for examination filed

Effective date: 20060914

AKX Designation fees paid

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

17Q First examination report despatched

Effective date: 20080612

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 502004011915

Country of ref document: DE

Date of ref document: 20110105

Kind code of ref document: P

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: MOETTELI & ASSOCIES SARL

REG Reference to a national code

Ref country code: NL

Ref legal event code: VDEP

Effective date: 20101124

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2356737

Country of ref document: ES

Kind code of ref document: T3

Effective date: 20110412

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110224

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110324

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

REG Reference to a national code

Ref country code: IE

Ref legal event code: FD4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110225

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IE

Payment date: 20110510

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

BERE Be: lapsed

Owner name: ELATRONIC A.G.

Effective date: 20110430

26N No opposition filed

Effective date: 20110825

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20110430

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 502004011915

Country of ref document: DE

Effective date: 20110825

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20110430

REG Reference to a national code

Ref country code: CH

Ref legal event code: PFA

Owner name: ELATRONIC AG

Free format text: ELATRONIC AG#BREITSCHACHENSTRASSE 10#9032 ENGELBURG (CH) -TRANSFER TO- ELATRONIC AG#BREITSCHACHENSTRASSE 10#9032 ENGELBURG (CH)

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20110429

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101124

REG Reference to a national code

Ref country code: CH

Ref legal event code: PCAR

Free format text: NEW ADDRESS: RATHAUSGASSE 1, 9320 ARBON (CH)

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101124

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 12

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20110510

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 13

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 14

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20230330

Year of fee payment: 20

P01 Opt-out of the competence of the unified patent court (upc) registered

Effective date: 20230524

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20230428

Year of fee payment: 20

Ref country code: ES

Payment date: 20230503

Year of fee payment: 20

Ref country code: DE

Payment date: 20230430

Year of fee payment: 20

Ref country code: CH

Payment date: 20230502

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20230328

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20230427

Year of fee payment: 20