EP3481143B1 - Heating system for operating a heating element - Google Patents

Heating system for operating a heating element Download PDF

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Publication number
EP3481143B1
EP3481143B1 EP17200251.1A EP17200251A EP3481143B1 EP 3481143 B1 EP3481143 B1 EP 3481143B1 EP 17200251 A EP17200251 A EP 17200251A EP 3481143 B1 EP3481143 B1 EP 3481143B1
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EP
European Patent Office
Prior art keywords
potential
switching elements
control
control signal
heating system
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EP17200251.1A
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German (de)
French (fr)
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EP3481143A1 (en
Inventor
Christoph Spitthöver
Torsten Lang
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.)
Vorwerk and Co Interholding GmbH
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Vorwerk and Co Interholding GmbH
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Priority to EP17200251.1A priority Critical patent/EP3481143B1/en
Publication of EP3481143A1 publication Critical patent/EP3481143A1/en
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Publication of EP3481143B1 publication Critical patent/EP3481143B1/en
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    • 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
    • H05B1/00—Details of electric heating devices
    • H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
    • H05B1/0227—Applications
    • H05B1/0252—Domestic applications
    • H05B1/0258—For cooking
    • 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
    • H05B3/00—Ohmic-resistance heating
    • H05B3/68—Heating arrangements specially adapted for cooking plates or analogous hot-plates
    • 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
    • H05B2213/00—Aspects relating both to resistive heating and to induction heating, covered by H05B3/00 and H05B6/00
    • H05B2213/07—Heating plates with temperature control means

Definitions

  • the present invention relates to a heating system for operating a heating element.
  • the invention also relates to a method for operating a heating element and a kitchen appliance with a heating system.
  • Heating systems can be used in electrical devices for various applications, such as, for example, in a kitchen appliance for heating a medium in a stirred vessel.
  • the heating system controls a heater, for example in the mixing vessel of the food processor, in such a way that the medium to be heated is heated to preselectable setpoint values.
  • z. B. heating systems are known in which a thick-film heating is used triac-controlled to heat the medium to be heated to the setpoints.
  • the medium temperature which is calculated, for example, by algorithms and based on the detection of a temperature sensor, can serve as a control variable for a controller of the heating system.
  • regulating the output of the heating element in order to maintain the setpoint values is often technically complex.
  • a system deviation that is unfavorable for some applications must be accepted.
  • Known heating systems are therefore often complex to manufacture and / or costly and / or too unreliable for certain applications, in particular for use in a kitchen appliance for the at least partially automated preparation of food.
  • the control deviation should be reduced so that an almost constant heating output can be achieved.
  • a further task can be to reduce the power loss during operation of the heating element, in particular a thick-film heater of a kitchen appliance.
  • an electrical connection is both a direct and an indirect connection, ie also via further electrical components, but in particular only if the connection is made in the same circuit or exclusively electrically (ie without galvanic separation).
  • the input connections can be electrically connected directly and are therefore at a common electrical potential, which can preferably be used as a reference potential for the gate-source voltage.
  • the common reference potential can thus be a common (and thus the same) electrical potential of the input connections (source connections) of the switching elements.
  • a switching frequency of the switching elements for controlling (i.e. also regulating) the heating element greater than 1 kHz or greater than 2 kHz or greater than 5 kHz or greater than 10 kHz or greater than 20 kHz is used.
  • the switching elements can switch a power of at least 0.5 kW or at least 1 kW.
  • the switching elements are designed as (for example N-channel) MOSFETs (ie metal-oxide-semiconductor field effect transistor) which, for example, have a high switch-on speed (slew rate) and / or a low capacitance at the gate -Connection, so as to reduce circuit losses.
  • the MOSFETs can have a low electrical resistance when switched on between the drain and the source connection in order to reduce the on-state losses.
  • the voltage at the control connection or gate connection is or must always be related to the voltage at the input connection or source connection.
  • the voltage difference between the input and control connection in the switched-on and in the switched-off state of the switching element must be kept constant, and thus in particular be independent of the voltage between the output connections of the switching elements.
  • This voltage between the output connections varies, for example, during operation between + 330 V and - 330 V.
  • the control connections of the switching elements can be controlled electrically independently of a mains voltage of the heating system (i.e.
  • the control circuit can be controlled by a control circuit and / or a control device can be controlled, which / which can be on the same (or alternatively on a further) ground potential as the load circuit.
  • the switching elements can be activated in a potential-free manner.
  • high-frequency activation of the heating element by the switching elements can offer the possibility of reducing the control deviation of the heating control and thus setting an almost constant heating output.
  • This also has the advantage that a desired heating output can be set particularly precisely and this heating output also remains constant.
  • the input connections of the switching elements can be directly electrically connected to one another and / or to a second ground potential and thus be at a common electrical potential (the common reference potential).
  • This common potential can thus be used as the common reference potential for the control signal, i.e. H.
  • H the common reference potential for the control signal
  • the control signal is generated as a potential difference, in particular generated potential-free, preferably so that a control voltage between the control connections and the input connections (i.e. in particular a gate-source voltage for the switching elements) remains at least almost constant.
  • the control voltage or gate-source voltage can have the same level for both control elements and, for example, have a different level when the control elements are switched on than when the switching elements are switched off, but are preferably kept at least almost constant in both cases.
  • the control elements always have the same status in normal operation for heating control, so that the alternating current can always be blocked for both current directions.
  • the heating element can be operated with an electrical power in the range 200 W to 5 kW, in particular 500 W to 3 kW, preferably 800 W to 2 kW, preferably 1 kW to 1.5 kW, and / or the switching elements in each case be designed to switch electrical power in these areas.
  • the heating element is supplied with energy in particular by an electrical voltage, in particular an (possibly high-frequency) alternating voltage, preferably a mains voltage, in a range from 100 V to 400 V, preferably 200 V to 300 V, preferably 230 V to 250 V.
  • the switching elements are switched in opposite directions (antiserial) in order to block both the positive and the negative half-wave of the voltage for the energy supply (mains voltage) when the switching elements are switched off.
  • block refers in particular to a state in which the flow of current to the heating element is predominantly or completely blocked by the switching elements.
  • the switching elements are preferably connected in series with the heating element and integrated into the load circuit (load circuit).
  • the control circuit (control circuit) and the load circuit are preferably designed separately from one another, so that in particular a current flow from the heating element to the control circuit or from one of the switching elements to the control circuit is prevented.
  • the different alignment of the switching elements in relation to the current direction is particularly useful in order to block any current direction through the switching elements (from and to the heating element).
  • a single switching element which can be implemented as a MOSFET, for example, can only block one current direction.
  • This is related to the structure of the switching elements, which can cause the switching elements to behave in a way that is similar to a parallel connection of a diode in the respective switching elements.
  • This property of the structure is also referred to below as a parasitic diode, and can, for. B. between a carrier material of a switching element and an output connection (drain connection) of this switching element.
  • the carrier material (bulk) is connected directly to an input connection (source connection) of the switching element, so that the flow of current can only be prevented in one direction.
  • a current flow from source to drain is possible (with a positive voltage) (whereas the current flow from drain to source is blocked when the switching element is switched off and released when the switching element is switched on).
  • the control of the switching elements may not be easy, e.g. B. by a transistor connected to the control terminal. In particular, this can possibly only bring about an adequate blocking of one of the current directions, since with such an activation a potential difference at the switching elements can fluctuate too much.
  • the heating element is supplied with a mains voltage, the problem arises that the potential at the input connection (source) may not be constant. In particular, if there is a changing voltage at the output connections (drain connections) of the switching elements (changing drain potential), an almost constant potential at the control connection (gate connection) or an almost constant voltage between the control connection and the input connection of the respective Switching elements are guaranteed.
  • a control voltage of the switching elements is always related to the input connection of a respective switching element.
  • a voltage between the input connection (source) and the control connection (gate) for the switched-on state and / or for the switched-off state is kept at least almost constant and thus at least essentially independent of a voltage between the output connections the switching elements is.
  • the voltage between the output connections varies, for example (in heating mode) between +330 V and - 330 V.
  • An average switching frequency of the switching elements which is used in a heating mode to regulate a heating power of the heating element is preferably at least 500 Hz or at least 1 kHz or at least 2 kHz. This has the advantage that the high-frequency control can significantly reduce any deviation in the heating control.
  • the load circuit and the control circuit are electrically connected to different grounds (in particular that means that the load circuit is connected to a first ground and the control circuit is connected to a second ground, to which the load circuit is not directly or galvanically connected), preferably a first ground potential (first Ground) is connected to the load circuit, and a second ground potential (second ground) is connected to the control circuit, is preferably electrically connected to the input terminals of the switching elements and / or the potential separation device, and particularly preferably forms the common reference potential.
  • the switching elements in particular the respective control connections
  • the potential-free control enables the control circuit (i.e. the control circuit for the switching elements) to be operated with the same supply voltage (e.g. the kitchen appliance, in particular mains voltage), in particular with the same ground potential as the load circuit with the Switching elements.
  • a further energy supply for the control circuit can be provided for this purpose, for example an AC / DC converter for electrical isolation in order to supply the control circuit with current.
  • the further energy supply can, for example, provide a further ground (second ground potential) which differs from the ground of the load circuit (first ground potential) and is provided in particular for the control circuit.
  • second ground potential which differs from the ground of the load circuit (first ground potential) and is provided in particular for the control circuit.
  • the control signal is preferably implemented as a voltage between the control connection (gate) and the input connection (source), ie a gate-source voltage, or as an (electrical) potential of the control connection (gate potential).
  • the control signal is kept at least almost constantly at a first level (for the switched-on state of the switching elements) and / or at a second level (for the switched-off state of the switching elements) by using the potential separation device, ie the floating control of the switching elements.
  • the switchover between the first and the second level can take place in that the potential separation device is controlled by a control device, for example by different voltages on the input side of the potential separation device.
  • the switching elements are each designed as a transistor, preferably as a field effect transistor, preferably as a MOSFET, so that a current flow between the input terminal and an output terminal of the respective switching element in each case by switching the respective switching elements on the basis of the control signal Direction is influenced, with the control connection of the respective switching elements preferably being electrically connected to the potential separation device for this purpose.
  • switching elements in particular MOSFETs, have a high switch-on speed (slew rate) and a low capacitance at the gate connection, so that the switching losses can be significantly reduced.
  • the switching elements are designed as N-channel MOSFETs.
  • an electrical connection between the control connections and the potential separation device can also be implemented indirectly via further components.
  • the potential separation device comprises a first connection which is electrically (e.g. indirectly, possibly via at least one control element, such as a transistor) connected to the control connections of the switching elements, and a second connection which is electrically ( in particular directly and / or via a second ground) is connected to the input connections of the switching elements in order to preferably generate a potential difference between the first and second connection for the control signal.
  • a first connection which is electrically (e.g. indirectly, possibly via at least one control element, such as a transistor) connected to the control connections of the switching elements
  • a second connection which is electrically ( in particular directly and / or via a second ground) is connected to the input connections of the switching elements in order to preferably generate a potential difference between the first and second connection for the control signal.
  • the switching elements may be (at least partially) integrated into the load circuit in such a way that they have different current blocking directions in the load circuit, in particular through a correspondingly different alignment of the switching elements or a parasitic diode (between a carrier material and an output connection ) of the switching elements, so that preferably different half-waves of a supply voltage of the load circuit can be blocked.
  • An alternating voltage for operating the heating element can thus be reliably controlled.
  • a control device for heating regulation is provided in order to preferably carry out an electrical activation of the potential separation device for generating the control signal, so that the switching elements can preferably be controlled at high frequency by the control signal, in particular with a switching frequency (in the high-frequency range) above 2 kHz or above 10 kHz or above 20 kHz.
  • the control device in the load or a control circuit
  • the first ground can differ from a second ground to which the control circuit is connected, the potential separation device preferably performing the potential separation between the load (or control circuit) and the control circuit, and / or a potential of the load circuit or control circuit galvanically to one Disconnects the potential of the control circuit.
  • the load circuit includes the heating element or can be electrically (detachably) connected to the heating element, the heating element preferably being designed as a thick-film heater and preferably being and / or integrable in a mixing vessel of a kitchen appliance .
  • the heating element can be part of the heating system according to the invention or can be designed separately therefrom.
  • the load circuit can be designed as an open circuit, which is closed by being connected to the heating element.
  • the heating system and heating element can be designed to be detachably connectable to one another.
  • the heating element can preferably be connected to (electrical) connecting elements which enable a detachable (electrical) connection to (electrical) counter-connecting elements of the heating system.
  • the heating element can be integrated into a mixing vessel of a kitchen appliance, the mixing vessel being designed, for example, to be detachable and / or integratable in the kitchen appliance.
  • the heating system can be integrated in a stationary part of the kitchen appliance, which, for example, can accommodate the mixing vessel. This enables flexible handling of the heating element and the kitchen appliance.
  • the load circuit comprises a voltage source, in particular an alternating voltage source, for providing the alternating current of the load circuit, which is preferably connected electrically (in series) via the switching elements is and / or can be connected to the heating element, in particular to transmit electrical power to the heating element, so that the power transmission can be controlled, in particular switched, by the switching elements as a function of the control signal.
  • a voltage source in particular an alternating voltage source
  • the heating element in particular to transmit electrical power to the heating element, so that the power transmission can be controlled, in particular switched, by the switching elements as a function of the control signal.
  • the potential separation device is electrically connected to the switching elements in such a way that, when a control signal is provided (directly), the potential separation device creates an at least almost constant voltage between the respective control connection, in particular a gate connection, and the respective input connection, in particular a source connection, can be generated, preferably at least almost independently of a polarity of the alternating current and / or of a voltage between output connections of the switching elements in normal operation. This ensures that the heating power is switched reliably even with the negative half-wave.
  • control circuit comprises an energy transmitter, preferably its own energy source and / or a switched-mode power supply and / or an AC / DC converter (ie rectifier), in order to preferably provide the power supply for the control circuit, and preferably the potential separation device for generation to supply the control signal with energy.
  • the energy transmitter can be connected to a first ground to which the load circuit is also connected.
  • the energy transmitter can provide a second mass different therefrom for the control circuit, in particular by implementing a potential separation. This has the advantage that the switching elements can be controlled particularly reliably.
  • AC / DC converters (sometimes also referred to as AC / DC converters) rectifiers that convert alternating current into direct current are preferred.
  • the potential separation device is designed as an optocoupler.
  • the potential separation device comprises a first separation unit, in particular a first winding, in the control circuit and a second separation unit, in particular a second winding, in the load circuit, preferably through the second separation unit, in particular a second winding , a potential difference can be generated for the control signal as a function of a voltage signal at the first separating unit, preferably the first winding.
  • the input connections are at a common source potential and are preferably connected to the control connections via the potential separation device, in particular so that the control signal can be used to switch off the switching elements in order to avoid both a negative and a positive Half-wave of a voltage supply in the load circuit to block the current flow. This enables reliable operation of the heating element.
  • the invention also generally includes a household appliance, such as. B. a food processor, with the heating system according to the invention for operating a heating element.
  • a household appliance such as. B. a food processor
  • the method according to the invention thus has the same advantages as have been described in detail with reference to a heating system according to the invention.
  • the method can be suitable for operating a heating system according to the invention.
  • the potential separation device can be electrically connected on the input side to a control circuit and / or load circuit, and in particular a control device, and on the output side to the control circuit, and in particular to the switching elements.
  • the connection to the respective switching element can serve to apply the generated control signal by transmitting the control signal to the switching elements via the connection.
  • an (at least almost constant) voltage is generated as the respective control signal for at least one of the control signals, for example a source-gate voltage for the switching elements.
  • the Control specification can be digitally (temporarily) stored in order to be evaluated by the control device.
  • the control specification is, for example, specific for a target temperature of a medium that is to be heated by the heating element.
  • the control specification is implemented as control information which, for example, determines a switching frequency with which the heating element is to be controlled.
  • the control specification it may be possible for the control specification to be determined as a function of a detection by a temperature sensor.
  • a first control specification can be first control information (which, for example, indicates blocking of the alternating current) and the second control specification can be second control information (which, for example, indicates enabling of the alternating current).
  • a heating system according to the invention is provided in order to carry out a heating regulation of the heating element on the basis of the detected temperature, in particular in order to determine an actuation specification in this way.
  • the kitchen appliance according to the invention thus brings the same advantages as have been described in detail with reference to a heating system according to the invention and / or a method according to the invention.
  • the kitchen appliance can be suitable to be operated according to a method according to the invention.
  • scales which can weigh the medium, in particular at least one food present in the mixing vessel.
  • Weight information of the food can, for example, be displayed to a user of the food processor via a display device such as a display or a touchscreen.
  • the recorded temperature of the temperature sensor and / or a set heating power is also displayed on the display device. It may be possible for the heating system to be controlled by the user on a Input device of the food processor, such as the touchscreen, is influenced or activated. This enables very convenient operation of the food processor.
  • FIG. 1 parts of a heating system 200 according to the invention are shown schematically. Further serves Fig. 1 to illustrate a method 100 according to the invention.
  • a load circuit 201 and a control circuit 202 are identified, whereby these are preferably circuits with separate grounds and / or (at least approximately) separate galvanic circuits 201, 202.
  • a control circuit can optionally be provided which, for example, comprises the control device 220 and is electrically connected to a potential separation device 270.
  • the control device 220 can also be integrated directly into the load circuit 201.
  • the potential separation device 270 (on the input side, e.g.
  • first ground first ground
  • second ground potential SGND second ground which is at least not directly connected to GND
  • an energy transmitter 280 can be provided which, for example, can provide the second ground potential SGND (this is also shown in more detail in FIG Fig. 2 shown).
  • the switching elements 250 i. H. a first switching element 250a and a second switching element 250b, which is oriented differently, can each be, for. B. be designed as a transistor or MOSFETs. Due to a respective parasitic diode 250.1, it is necessary to provide both switching elements 250 in an anti-series connection in order to completely block an alternating voltage U or alternating current I of a voltage source 260, in particular alternating voltage source 260 (i.e. in both current directions).
  • the individual switching elements 250 can have an input connection 250.3 with a source potential S and an output connection 250.4 with a drain potential D and a control connection 250.2 with a control potential G, in particular gate potential G.
  • the potential separation device 270 can have on the output side (on the control circuit 202) in particular at least one first (output) connection 270.1 and the second (output) connection 270.2, which are each connected to the control circuit 202. Further (input) connections can also be provided on the input side, which are connected, for example, on the control device side or on the control circuit side.
  • a first separating unit 270.3 (e.g. first winding 270.3) and on the output side a second separating unit 270.4 (e.g. second winding 270.4) of the potential separation device 270 are also shown by way of example on the input side, which illustrate the galvanic separation can also be an optocoupler or the like, which therefore does not have to have any windings.
  • the first connection 270.1 of the potential separation device 270 is z. B. via a first resistor R1 and / or via at least one control element 230 with the control connection 250.2 of the first switching element 250a and via a second resistor R2 and / or via at least one (possibly further) control element 230 with the control connection 250.2 of the second switching element 250b electrically connected.
  • a third resistor R3 can be provided, which z. B. with a high Resistance is designed to increase the stability of the circuit.
  • the second connection 270.2 of the potential separation device 270 is electrically connected, for example (for example directly and / or via a second ground potential) to the input connections 250.3 of the switching elements 250, ie to the source potential S.
  • a common reference potential S can be created for the control signal A and / or the control signal A can be applied to the switching elements 250 according to a method 100 according to the invention.
  • the control signal A e.g. as gate-source voltage
  • the switching elements 250 ie to transfer the switching elements 250 from an open state, in which the flow of a current I in the load circuit 201 is prevented, to a closed state , in which the flow of current is allowed, and / or vice versa.
  • the heating power of a heating element 210, in particular a thick-film heater 210, in the load circuit 201 can be reliably controlled and / or regulated.
  • Fig. 2 is the in Fig. 1 or a similar circuit configuration of a heating system 200 is shown schematically.
  • an energy supply device 290 for the control circuit 202 is shown, which, for example, has a voltage source X1, which z. B. supplies a mains voltage and / or that of the voltage source 260 in Fig. 1 corresponds to.
  • This can, for example, be connected to an energy transmitter 280, which z. B. provides the voltage supply for the control circuit 202 as a rectifier.
  • a second ground potential SGND can also be provided, which differs from a first ground potential GND of the load circuit 201, that is to say, in particular, is designed to be electrically isolated from it.
  • a first voltage V1 can be provided by this or by the energy transmitter 280, which z. B. is used to operate at least one control element 230.
  • the control element (s) 230 are, for example, a semiconductor switch, for example a transistor or MOSFET, in order to generate the control signal A, in particular at a control potential G of the switching elements 250 a control element 230 is controlled by the potential separation device 270 and / or the first voltage is generated in an electrically isolated manner and / or the switching elements 250 are each connected to the second ground potential SGND.
  • the potential separation device 270 is, for example a second voltage V2 operated, which can be provided by the energy transmitter 280.
  • the activation signal A generated in a potential-free manner is initiated, for example, by a control device 220, which in particular activates the potential separation device 270.
  • the control device 220 provides, for example, a voltage supply U270 for the potential separation device 270 and / or a control signal KS at an input of the potential separation device 270.
  • a mixing vessel 2 of a food processor 1 is shown schematically.
  • a medium 20 is shown in the stirred vessel 2 with a stirrer 3, the medium 20 being able to be heated by a heating element 210.
  • the heating element 210 is integrated, for example, in a mixing vessel base 2.1, with the heating element 210 then optionally also being able to be designed separately from the kitchen appliance 1.
  • the mixing vessel 2 can be detachably connected to the heating system 200 of the kitchen appliance 1, it also being possible for electrical contacts to be provided for integrating the heating element 210 into the load circuit 201.
  • the activation of the heating element 210 is then controlled, for example, by a control device 220 which, for example, is also connected to the load circuit 201 and / or is integrated into an electronics of the kitchen appliance 1.
  • a control device 220 which, for example, is also connected to the load circuit 201 and / or is integrated into an electronics of the kitchen appliance 1.
  • temperature values can be evaluated by the detection of a temperature sensor 4 by the control device 220, the temperature sensor 4 being integrated, for example, in the stirred vessel.

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  • Food Science & Technology (AREA)
  • Control Of Resistance Heating (AREA)

Description

Die vorliegende Erfindung betrifft ein Heizsystem zum Betreiben eines Heizelements. Ferner bezieht sich die Erfindung auf ein Verfahren zum Betreiben eines Heizelements sowie eine Küchenmaschine mit einem Heizsystem.The present invention relates to a heating system for operating a heating element. The invention also relates to a method for operating a heating element and a kitchen appliance with a heating system.

Heizsysteme können bei elektrischen Geräten für verschiedene Anwendungen zum Einsatz kommen, wie bspw. bei einer Küchenmaschine zur Erhitzung eines Mediums in einem Rührgefäß. Dabei führt das Heizsystem eine Ansteuerung einer Heizung, bspw. in dem Rührgefäß der Küchenmaschine, derart aus, dass das zu erhitzende Medium auf vorwählbare Sollwerte erhitzt wird.Heating systems can be used in electrical devices for various applications, such as, for example, in a kitchen appliance for heating a medium in a stirred vessel. The heating system controls a heater, for example in the mixing vessel of the food processor, in such a way that the medium to be heated is heated to preselectable setpoint values.

So sind z. B. Heizsysteme bekannt, bei welchen eine Dickschichtheizung triacgesteuert eingesetzt wird, um das aufzuheizende Medium auf die Sollwerte zu erhitzen. Dabei kann als Regelgröße für einen Regler des Heizsystems die Medientemperatur dienen, welche bspw. durch Algorithmen und anhand der Erfassung eines Temperatursensors berechnet wird.So are z. B. heating systems are known in which a thick-film heating is used triac-controlled to heat the medium to be heated to the setpoints. The medium temperature, which is calculated, for example, by algorithms and based on the detection of a temperature sensor, can serve as a control variable for a controller of the heating system.

Häufig wird ein Heizelement aus Gründen der Sicherheit und der Lebensdauer mit Wechselstrom durchflossen. Oft können allerdings derartige Heizungssystemen bspw. mit einer Triacsteuerung nur mit großen Schaltintervallen betrieben werden. Begrenzend wirkt sich dabei insbesondere die Notwendigkeit aus, Störungen durch Flicker zu reduzieren.Frequently, alternating current flows through a heating element for reasons of safety and service life. Often, however, such heating systems can only be operated with large switching intervals, for example with a triac control. In particular, the need to reduce interference from flicker has a limiting effect.

Bei einem großen Schaltintervall, wie bspw. 4 s bei herkömmlichen Heizungssystemen, ist eine Regelung der Leistung des Heizelements zur Einhaltung der Sollwerte oft technisch aufwendig. Insbesondere ist eine für manche Anwendungen ungünstige Regelabweichung in Kauf zu nehmen. Damit sind bekannte Heizungssysteme oft aufwendig herzustellen und/oder kostenaufwendig und/oder zu unzuverlässig für bestimmte Anwendungen, insbesondere für den Einsatz bei einer Küchenmaschine zur zumindest teilweise automatisierten Zubereitung von Lebensmitteln.With a large switching interval, such as, for example, 4 s in conventional heating systems, regulating the output of the heating element in order to maintain the setpoint values is often technically complex. In particular, a system deviation that is unfavorable for some applications must be accepted. Known heating systems are therefore often complex to manufacture and / or costly and / or too unreliable for certain applications, in particular for use in a kitchen appliance for the at least partially automated preparation of food.

Aus der DE 44 46 796 A1 ist ein gattungsgemäßes Heizsystem bekannt.From the DE 44 46 796 A1 a generic heating system is known.

Es ist daher eine Aufgabe der vorliegenden Erfindung, die voranstehend genannten Nachteile zumindest teilweise zu beheben. Insbesondere ist es eine Aufgabe, ein verbessertes Heizsystem vorzuschlagen, bei welchem der technische Aufwand reduziert und/oder die Zuverlässigkeit verbessert wird. Dabei soll insbesondere die Regelabweichung reduziert werden, sodass eine nahezu konstante Heizleistung erzielt werden kann. Eine weitere Aufgabe kann eine Reduzierung der Verlustleistung beim Betrieb des Heizelements sein, insbesondere einer Dickschichtheizung einer Küchenmaschine.It is therefore an object of the present invention to at least partially remedy the disadvantages mentioned above. In particular, it is an object to propose an improved heating system in which the technical effort is reduced and / or the reliability is improved. In particular, the control deviation should be reduced so that an almost constant heating output can be achieved. A further task can be to reduce the power loss during operation of the heating element, in particular a thick-film heater of a kitchen appliance.

Die voranstehende Aufgabe wird gelöst durch ein Heizsystem mit den Merkmalen des Anspruchs 1, ein Verfahren mit den Merkmalen des Anspruchs 13 sowie durch eine Küchenmaschine mit den Merkmalen des Anspruchs 14. Weitere Merkmale und Details der Erfindung ergeben sich aus den jeweiligen Unteransprüchen, der Beschreibung und den Zeichnungen. Dabei gelten Merkmale und Details, die im Zusammenhang mit dem erfindungsgemäßen Heizsystem beschrieben sind, selbstverständlich auch im Zusammenhang mit dem erfindungsgemäßen Verfahren sowie der erfindungsgemäßen Küchenmaschine, und jeweils umgekehrt, sodass bezüglich der Offenbarung zu den einzelnen Erfindungsaspekten stets wechselseitig Bezug genommen wird bzw. werden kann.The above object is achieved by a heating system with the features of claim 1, a method with the features of claim 13 and a kitchen appliance with the features of claim 14. Further features and details of the invention emerge from the respective subclaims, the description and the drawings. Features and details that are described in connection with the heating system according to the invention naturally also apply in connection with the method according to the invention and the kitchen appliance according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made to the individual aspects of the invention .

Insbesondere wird im Folgenden - sofern nicht ausdrücklich anders beschrieben - unter einer elektrischen Verbindung sowohl eine direkte als auch eine indirekte Verbindung, d. h. auch über weitere elektrische Bauelemente, verstanden, allerdings insbesondere nur, sofern die Verbindung im selben Stromkreis bzw. ausschließlich elektrisch erfolgt (d. h. ohne galvanische Trennung).In particular, in the following - unless expressly described otherwise - an electrical connection is both a direct and an indirect connection, ie also via further electrical components, but in particular only if the connection is made in the same circuit or exclusively electrically (ie without galvanic separation).

Die voranstehende Aufgabe wird insbesondere gelöst durch ein Heizsystem, insbesondere Steuerungs- und/oder Regelungssystem, zum Betreiben eines Heizelements, insbesondere bei einer Küchenmaschine, aufweisend:

  • einen Lastkreis, welcher zumindest zwei elektronische Schaltelemente, insbesondere Halbleiter-Schaltelemente, mit jeweils einem Steuerungsanschluss und jeweils einem Eingangsanschluss umfasst, wobei vorzugsweise die Schaltelemente antiseriell (im Lastkreis) geschaltet sind, um einen Wechselstrom (des Lastkreises) zum Heizelement zu beeinflussen,
  • einen Ansteuerungskreis, um ein elektrisches Ansteuerungssignal zur Ansteuerung der Schaltelemente (insbesondere am jeweiligen Steuerungsanschluss) zu initiieren, wobei vorzugsweise die Schaltelemente auch mit dem Ansteuerungskreis verbunden sind,
  • eine Potentialtrennvorrichtung, um den Lastkreis mit dem Ansteuerungskreis zu verbinden und/oder um das Ansteuerungssignal an den Steuerungsanschlüssen (und insbesondere auch an den Eingangsanschlüssen) derart bereitzustellen, insbesondere potentialfrei zu erzeugen, dass ein elektrisches Potential an den Eingangsanschlüssen ein gemeinsames Bezugspotential der Schaltelemente für das Ansteuerungssignal bildet. Hierzu kann die Potentialtrennvorrichtung bspw. sowohl mit den Steuerungsanschlüssen als auch mit den Eingangsanschlüssen elektrisch verbunden sein, um vorzugsweise das Ansteuerungssignal als eine elektrische Spannung zwischen diesen Anschlüssen zu erzeugen.
The above object is achieved in particular by a heating system, in particular a control and / or regulating system, for operating a heating element, in particular in a kitchen appliance, having:
  • a load circuit which comprises at least two electronic switching elements, in particular semiconductor switching elements, each with a control connection and an input connection each, the switching elements preferably being connected in antiseries (in the load circuit) in order to influence an alternating current (of the load circuit) to the heating element,
  • a control circuit to initiate an electrical control signal to control the switching elements (in particular at the respective control connection), the switching elements preferably also being connected to the control circuit,
  • a potential separation device to connect the load circuit to the control circuit and / or to provide the control signal at the control connections (and in particular also at the input connections) in such a way, in particular to generate potential-free, that an electrical potential at the input connections is a common reference potential of the switching elements for the Forms control signal. For this purpose, the potential separation device can be electrically connected, for example, both to the control connections and to the input connections, in order to preferably generate the control signal as an electrical voltage between these connections.

In anderen Worten können die Eingangsanschlüsse elektrisch direkt verbunden sein und liegen daher auf einem gemeinsamen elektrischen Potential, welches vorzugsweise als Bezugspotential der Gate-Source-Spannung genutzt werden kann. Insbesondere kann das gemeinsame Bezugspotential somit ein gemeinsames (und damit gleiches) elektrisches Potential der Eingangsanschlüsse (Source-Anschlüsse) der Schaltelemente sein. Dies hat den Vorteil eines einfachen und zuverlässigen Schaltungsaufbaus und ggf., dass kostensparend lediglich eine Spannungsquelle zum Schalten der Schaltelemente benötigt wird. Insbesondere betrifft dabei der Last- und Ansteuerungskreis separate Schaltanordnungen, welche ggf. elektrisch miteinander verbunden sein können und/oder auch separate Strompfade und/oder Stromkreise aufweisen können.In other words, the input connections can be electrically connected directly and are therefore at a common electrical potential, which can preferably be used as a reference potential for the gate-source voltage. In particular, the common reference potential can thus be a common (and thus the same) electrical potential of the input connections (source connections) of the switching elements. This has the advantage of a simple and reliable circuit structure and possibly that, in a cost-saving manner, only one voltage source is required for switching the switching elements becomes. In particular, the load and control circuit relates to separate switching arrangements which, if necessary, can be electrically connected to one another and / or can also have separate current paths and / or circuits.

Es kann insbesondere vorgesehen sein, dass eine Schaltfrequenz der Schaltelemente zur Ansteuerung (d. h. auch Regelung) des Heizelements größer als 1 kHz oder größer als 2 kHz oder größer als 5 kHz oder größer als 10 kHz oder größer als 20 kHz genutzt wird. Alternativ oder zusätzlich kann hierbei durch die Schaltelemente eine Leistung von mindestens 0,5 kW oder mindestens 1 kW geschaltet werden. Weiter kann es vorgesehen sein, dass die Schaltelemente als (bspw. N-Kanal) MOSFETs (d. h. Metall-Oxid-Halbleiter-Feldeffekttransistor) ausgeführt sind, welche bspw. eine hohe Einschaltgeschwindigkeit (Slew-Rate) und/oder eine geringe Kapazität am Gate-Anschluss aufweisen, um so die Schaltungsverluste zu reduzieren. Bspw. können die MOSFETs über einen niedrigen elektrischen Widerstand im eingeschalteten Zustand zwischen dem Drain- und dem Sourceanschluss verfügen, um die Durchlassverluste zu reduzieren.It can in particular be provided that a switching frequency of the switching elements for controlling (i.e. also regulating) the heating element greater than 1 kHz or greater than 2 kHz or greater than 5 kHz or greater than 10 kHz or greater than 20 kHz is used. As an alternative or in addition, the switching elements can switch a power of at least 0.5 kW or at least 1 kW. Furthermore, it can be provided that the switching elements are designed as (for example N-channel) MOSFETs (ie metal-oxide-semiconductor field effect transistor) which, for example, have a high switch-on speed (slew rate) and / or a low capacitance at the gate -Connection, so as to reduce circuit losses. For example, the MOSFETs can have a low electrical resistance when switched on between the drain and the source connection in order to reduce the on-state losses.

Insbesondere kann es notwendig sein, dass (aufgrund des wechselnden Potentials an den Schaltelementen) die Spannung am Steuerungsanschluss bzw. Gate-Anschluss immer in Bezug zur Spannung am Eingangsanschluss bzw. Source-Anschluss steht bzw. stehen muss. In anderen Worten muss dann die Spannungsdifferenz zwischen dem Eingangs- und Steuerungsanschluss im eingeschalteten sowie im ausgeschalteten Zustand des Schaltelements jeweils konstant gehalten werden, und somit insbesondere unabhängig von der Spannung zwischen den Ausgangsanschlüssen der Schaltelemente sein. Diese Spannung zwischen den Ausgangsanschlüssen variiert bspw. im Betrieb zwischen + 330 V und - 330 V. Bspw. können hierzu die Steuerungsanschlüsse der Schaltelemente elektrisch unabhängig von einer Netzspannung des Heizsystems (d. h. potentialfrei) angesteuert werden, insbesondere damit der Ansteuerungskreis durch einen Steuerkreis und/oder einer Kontrollvorrichtung angesteuert werden kann, welcher/welche auf dem gleichen (oder alternativ auf einen weiteren) Massepotential liegen kann wie der Lastkreis. In anderen Worten kann die Ansteuerung der Schaltelemente potentialfrei erfolgen. Zudem kann eine hochfrequente Ansteuerung des Heizelements durch die Schaltelemente die Möglichkeit bieten, die Regelabweichung der Heizungsregelung zu reduzieren und somit eine nahezu konstante Heizleistung einzustellen.In particular, it may be necessary that (due to the changing potential at the switching elements) the voltage at the control connection or gate connection is or must always be related to the voltage at the input connection or source connection. In other words, the voltage difference between the input and control connection in the switched-on and in the switched-off state of the switching element must be kept constant, and thus in particular be independent of the voltage between the output connections of the switching elements. This voltage between the output connections varies, for example, during operation between + 330 V and - 330 V. For this purpose, the control connections of the switching elements can be controlled electrically independently of a mains voltage of the heating system (i.e. potential-free), in particular so that the control circuit can be controlled by a control circuit and / or a control device can be controlled, which / which can be on the same (or alternatively on a further) ground potential as the load circuit. In other words, the switching elements can be activated in a potential-free manner. In addition, high-frequency activation of the heating element by the switching elements can offer the possibility of reducing the control deviation of the heating control and thus setting an almost constant heating output.

Bevorzugt kann es daher vorgesehen sein, dass eine potentialfreie und/oder hochfrequente (d. h. über 2 kHz) Ansteuerung der Schaltelemente, insbesondere MOSFETs, erfolgt. Hierdurch kann auch der Vorteil erzielt werden, dass eine gewünschte Heizleistung besonders genau eingestellt werden kann, und diese Heizleistung auch konstant bleibt.Provision can therefore preferably be made for the switching elements, in particular MOSFETs, to be actuated in a potential-free and / or high-frequency manner (i.e. above 2 kHz). This also has the advantage that a desired heating output can be set particularly precisely and this heating output also remains constant.

Bspw. können die Eingangsanschlüsse der Schaltelemente direkt elektrisch miteinander und/oder einem zweiten Massepotential verbunden sein und somit auf einem gemeinsamen elektrischen Potential (dem gemeinsamen Bezugspotential) liegen. Damit kann dieses gemeinsame Potential als das gemeinsame Bezugspotential für das Ansteuerungssignal, d. h. bspw. zur Bildung einer Gate-Source-Spannung bzw. als Bezugspunkt für ein Potential am Steuerungsanschluss, dienen. Damit kann der Vorteil erzielt werden, dass ein besonders einfacher und kostengünstiger Aufbau ermöglicht wird, und insbesondere lediglich eine Spannungsquelle zum Schalten der Schaltelemente benötigt wird.For example, the input connections of the switching elements can be directly electrically connected to one another and / or to a second ground potential and thus be at a common electrical potential (the common reference potential). This common potential can thus be used as the common reference potential for the control signal, i.e. H. For example, to form a gate-source voltage or as a reference point for a potential at the control connection. In this way, the advantage can be achieved that a particularly simple and cost-effective structure is made possible, and in particular only one voltage source is required for switching the switching elements.

Insbesondere kann es herkömmlicherweise aufgrund des Betriebs mit dem Wechselstrom das Problem geben, dass das gemeinsame Bezugspotential variiert. Ein solches nichtkonstantes gemeinsames Bezugspotential kann die Ansteuerung der Schaltelemente deutlich erschweren. Daher kann es erfindungsgemäß vorgesehen sein, dass das Ansteuerungssignal als Potentialdifferenz erzeugt wird, insbesondere potentialfrei erzeugt wird, vorzugsweise sodass eine Steuerungsspannung zwischen den Steuerungsanschlüssen und den Eingangsanschlüssen (d. h. insbesondere eine Gate-Source-Spannung für die Schaltelemente) zumindest nahezu konstant bleibt. Die Steuerungsspannung bzw. Gate-Source-Spannung kann dabei für beide Steuerelemente die gleiche Höhe aufweisen, und bspw. im eingeschalteten Zustand der Steuerelemente eine andere Höhe aufweisen als im ausgeschalteten Zustand der Schaltelemente, vorzugsweise in beiden Fällen jedoch zumindest nahezu konstant gehalten werden. Bspw. haben dabei die Steuerelemente stets den gleichen Zustand im Normalbetrieb zur Heizregelung, sodass der Wechselstrom stets für beide Stromrichtungen gesperrt werden kann.In particular, conventionally, due to the operation with the alternating current, there may be a problem that the common reference potential varies. Such a non-constant common reference potential can make the control of the switching elements much more difficult. Therefore, it can be provided according to the invention that the control signal is generated as a potential difference, in particular generated potential-free, preferably so that a control voltage between the control connections and the input connections (i.e. in particular a gate-source voltage for the switching elements) remains at least almost constant. The control voltage or gate-source voltage can have the same level for both control elements and, for example, have a different level when the control elements are switched on than when the switching elements are switched off, but are preferably kept at least almost constant in both cases. For example, the control elements always have the same status in normal operation for heating control, so that the alternating current can always be blocked for both current directions.

Gemäß einem weiteren Vorteil kann das Heizelement mit einer elektrischen Leistung im Bereich 200 W bis 5 kW, insbesondere 500 W bis 3 kW, vorzugsweise 800 W bis 2 kW, bevorzugt 1 kW bis 1,5 kW betrieben werden und/oder die Schaltelemente jeweils dazu ausgeführt sein, eine elektrische Leistung in diesen Bereichen zu schalten. Die Energieversorgung des Heizelements erfolgt insbesondere durch eine elektrische Spannung, insbesondere eine (ggf. hochfrequente) Wechselspannung, vorzugsweise eine Netzspannung, in einem Bereich von 100 V bis 400 V, vorzugsweise 200 V bis 300 V, bevorzugt 230 V bis 250 V. Bevorzugt sind die Schaltelemente dabei gegensinnig (antiseriell) geschaltet, um sowohl die positive als auch die negative Halbwelle der Spannung zur Energieversorgung (Netzspannung) im ausgeschalteten Zustand der Schaltelemente zu sperren. Unter "sperren" wird dabei insbesondere ein Zustand bezeichnet, in welchem der Stromfluss zum Heizelement durch die Schaltelemente überwiegend oder vollständig gesperrt ist. Vorzugsweise sind hierzu die Schaltelemente in Reihe mit dem Heizelement verschaltet und in den Lastkreis (Laststromkreis) integriert. Bevorzugt ist der Ansteuerungskreis (Ansteuerungsstromkreis) und der Lastkreis separat voneinander ausgebildet, sodass insbesondere ein Stromfluss vom Heizelement zum Ansteuerungskreis oder von einem der Schaltelemente zum Ansteuerungskreis verhindert ist.According to a further advantage, the heating element can be operated with an electrical power in the range 200 W to 5 kW, in particular 500 W to 3 kW, preferably 800 W to 2 kW, preferably 1 kW to 1.5 kW, and / or the switching elements in each case be designed to switch electrical power in these areas. The heating element is supplied with energy in particular by an electrical voltage, in particular an (possibly high-frequency) alternating voltage, preferably a mains voltage, in a range from 100 V to 400 V, preferably 200 V to 300 V, preferably 230 V to 250 V. Preferred the switching elements are switched in opposite directions (antiserial) in order to block both the positive and the negative half-wave of the voltage for the energy supply (mains voltage) when the switching elements are switched off. In this context, “block” refers in particular to a state in which the flow of current to the heating element is predominantly or completely blocked by the switching elements. For this purpose, the switching elements are preferably connected in series with the heating element and integrated into the load circuit (load circuit). The control circuit (control circuit) and the load circuit are preferably designed separately from one another, so that in particular a current flow from the heating element to the control circuit or from one of the switching elements to the control circuit is prevented.

Die unterschiedliche Ausrichtung der Schaltelemente in Bezug auf die Stromrichtung ist insbesondere deshalb sinnvoll, um jede Stromrichtung durch die Schaltelemente (von und zu dem Heizelement) zu sperren. Insbesondere kann ein einzelnes Schaltelement, welches bspw. als MOSFET ausgeführt sein kann, dabei lediglich eine Stromrichtung sperren. Dies hängt mit dem Aufbau der Schaltelemente zusammen, welcher ein Verhalten der Schaltelemente bewirken kann, der einer Parallelschaltung einer Diode bei den jeweiligen Schaltelementen ähnelt. Diese Eigenschaft des Aufbaus wird im Folgenden auch mit parasitärer Diode bezeichnet, und kann sich z. B. zwischen einem Trägermaterial eines Schaltelements und einem Ausgangsanschluss (Drain-Anschluss) dieses Schaltelements ausbilden. Üblicherweise ist (insbesondere bei MOSFETs) das Trägermaterial (Bulk) direkt mit einem Eingangsanschluss (Source-Anschluss) des Schaltelements verbunden, sodass der Stromfluss nur in einer Richtung unterbunden werden kann. Bspw. ist (bei einer positiven Spannung) ein Stromfluss von Source zu Drain möglich (wohingegen der Stromfluss von Drain zu Source im ausgeschalteten Zustand gesperrt und im eingeschalteten Zustand des Schaltelements freigegeben ist). Durch die Nutzung von wenigstens zwei Schaltelementen kann dieses Problem zuverlässig und kostengünstig gelöst werden.The different alignment of the switching elements in relation to the current direction is particularly useful in order to block any current direction through the switching elements (from and to the heating element). In particular, a single switching element, which can be implemented as a MOSFET, for example, can only block one current direction. This is related to the structure of the switching elements, which can cause the switching elements to behave in a way that is similar to a parallel connection of a diode in the respective switching elements. This property of the structure is also referred to below as a parasitic diode, and can, for. B. between a carrier material of a switching element and an output connection (drain connection) of this switching element. Usually (especially in the case of MOSFETs) the carrier material (bulk) is connected directly to an input connection (source connection) of the switching element, so that the flow of current can only be prevented in one direction. For example, a current flow from source to drain is possible (with a positive voltage) (whereas the current flow from drain to source is blocked when the switching element is switched off and released when the switching element is switched on). By using at least two switching elements, this problem can be solved reliably and inexpensively.

Ggf. kann für bestimmte Anwendungen, insbesondere beim Schalten einer Wechselspannung und/oder bei einem Schalten mit hoher Frequenz, die Ansteuerung der Schaltelemente nicht ohne Weiteres, z. B. durch einen mit dem Steuerungsanschluss verbundenen Transistor, erfolgen. Insbesondere kann dies ggf. nur die hinreichende Sperrung einer der Stromrichtungen bewirken, da bei einer solchen Ansteuerung eine Potentialdifferenz an den Schaltelementen zu stark schwanken kann. So tritt bei einer Versorgung des Heizelements mit einer Netzspannung das Problem auf, dass das Potential am Eingangsanschluss (Source) ggf. nicht konstant ist. Insbesondere wenn eine wechselnde Spannung an den Ausgangsanschlüssen (Drain-Anschlüssen) der Schaltelemente anliegt (wechselndes Drain-Potential), muss im besonderen Maße ein nahezu konstantes Potential am Steuerungsanschluss (Gate-Anschluss) bzw. eine nahezu konstante Spannung zwischen Steuerungsanschluss und Eingangsanschluss der jeweiligen Schaltelemente gewährleistet werden. In anderen Worten kann es vorgesehen sein, dass eine Ansteuerungsspannung der Schaltelemente (bzw. ein Potential am Steuerungsanschluss) immer im Bezug zum Eingangsanschluss eines jeweiligen Schaltelements steht. Insbesondere ist es hierzu vorgesehen, dass eine Spannung zwischen dem Eingangsanschluss (Source) und dem Steuerungsanschluss (Gate) für den eingeschalteten Zustand und/oder für den ausgeschalteten Zustand jeweils zumindest nahezu konstant gehalten wird und somit zumindest im Wesentlichen unabhängig von einer Spannung zwischen den Ausgangsanschlüssen der Schaltelemente ist. Die Spannung zwischen den Ausgangsanschlüssen variiert dabei bspw. (im Heizbetrieb) zwischen +330 V und - 330 V.For certain applications, in particular when switching an alternating voltage and / or when switching at high frequency, the control of the switching elements may not be easy, e.g. B. by a transistor connected to the control terminal. In particular, this can possibly only bring about an adequate blocking of one of the current directions, since with such an activation a potential difference at the switching elements can fluctuate too much. When the heating element is supplied with a mains voltage, the problem arises that the potential at the input connection (source) may not be constant. In particular, if there is a changing voltage at the output connections (drain connections) of the switching elements (changing drain potential), an almost constant potential at the control connection (gate connection) or an almost constant voltage between the control connection and the input connection of the respective Switching elements are guaranteed. In other words, it can be provided that a control voltage of the switching elements (or a potential at the control connection) is always related to the input connection of a respective switching element. In particular, it is provided for this purpose that a voltage between the input connection (source) and the control connection (gate) for the switched-on state and / or for the switched-off state is kept at least almost constant and thus at least essentially independent of a voltage between the output connections the switching elements is. The voltage between the output connections varies, for example (in heating mode) between +330 V and - 330 V.

Vorzugsweise beträgt eine durchschnittliche Schaltfrequenz der Schaltelemente, welche in einem Heizbetrieb zur Regelung einer Heizleistung des Heizelements genutzt wird, mindestens 500 Hz oder mindestens 1 kHz oder mindesten 2kHz. Dies hat den Vorteil, dass durch die hochfrequente Ansteuerung eine Regelabweichung der Heizungsregelung deutlich reduziert werden kann.An average switching frequency of the switching elements which is used in a heating mode to regulate a heating power of the heating element is preferably at least 500 Hz or at least 1 kHz or at least 2 kHz. This has the advantage that the high-frequency control can significantly reduce any deviation in the heating control.

Des Weiteren ist es im Rahmen der Erfindung optional möglich, dass der Lastkreis und der Ansteuerungskreis elektrisch mit unterschiedlichen Massen verbunden sind (insbesondere heißt das, dass der Lastkreis mit einer ersten Masse verbunden ist, und der Ansteuerungskreis mit einer zweiten Masse verbunden ist, mit welcher der Lastkreis nicht direkt bzw. galvanisch verbunden ist), wobei vorzugsweise ein erstes Massepotential (erste Masse) mit dem Lastkreis verbunden ist, und ein zweites Massepotential (zweite Masse) mit dem Ansteuerungskreis verbunden ist, bevorzugt mit den Eingangsanschlüssen der Schaltelemente und/oder der Potentialtrennvorrichtung elektrisch verbunden ist, und besonders bevorzugt das gemeinsame Bezugspotential bildet. In anderen Worten können insbesondere die Schaltelemente (insbesondere die jeweiligen Steuerungsanschlüsse) potentialfrei angesteuert werden, d. h. vorzugsweise (zumindest nahezu) unabhängig von der Energieversorgung bzw. Netzspannung für das Heizelement. Dies ermöglicht eine besonders genaue und zuverlässige Steuerung der Schaltelemente, insbesondere da ein zumindest nahezu konstantes Ansteuerungssignal gewährleistet werden kann. Insbesondere ermöglicht die potentialfreie Ansteuerung, dass der Ansteuerungskreis (d. h. die Steuerschaltung für die Schaltelemente) ggf. nach einer Potentialtrennung mit der gleichen Versorgungsspannung (bspw. der Küchenmaschine, insbesondere Netzspannung) insbesondere mit dem gleichen Masse-Potential betrieben werden kann wie der Lastkreis mit den Schaltelementen. Bspw. kann hierzu noch eine weitere Energieversorgung für den Ansteuerungskreis vorgesehen sein, bspw. ein AC/DC Wandler zu Potentialtrennung, um den Ansteuerungskreis mit Strom zu versorgen. Hierbei kann die weitere Energieversorgung bspw. eine weitere Masse (zweites Massepotential) bereitstellen, welche sich von der Masse des Lastkreises (erstes Massepotential) unterscheidet, und insbesondere für den Ansteuerungskreis vorgesehen ist. Somit kann ein einfacherer und kostengünstiger Aufbau erzielt werden.Furthermore, it is optionally possible within the scope of the invention that the load circuit and the control circuit are electrically connected to different grounds (in particular that means that the load circuit is connected to a first ground and the control circuit is connected to a second ground, to which the load circuit is not directly or galvanically connected), preferably a first ground potential (first Ground) is connected to the load circuit, and a second ground potential (second ground) is connected to the control circuit, is preferably electrically connected to the input terminals of the switching elements and / or the potential separation device, and particularly preferably forms the common reference potential. In other words, in particular the switching elements (in particular the respective control connections) can be activated in a potential-free manner, ie preferably (at least almost) independently of the energy supply or mains voltage for the heating element. This enables a particularly precise and reliable control of the switching elements, in particular since an at least almost constant control signal can be guaranteed. In particular, the potential-free control enables the control circuit (i.e. the control circuit for the switching elements) to be operated with the same supply voltage (e.g. the kitchen appliance, in particular mains voltage), in particular with the same ground potential as the load circuit with the Switching elements. For example, a further energy supply for the control circuit can be provided for this purpose, for example an AC / DC converter for electrical isolation in order to supply the control circuit with current. Here, the further energy supply can, for example, provide a further ground (second ground potential) which differs from the ground of the load circuit (first ground potential) and is provided in particular for the control circuit. A simpler and cheaper structure can thus be achieved.

Bevorzugt ist dabei das Ansteuerungssignal als eine Spannung zwischen dem Steuerungsanschluss (Gate) und dem Eingangsanschluss (Source), d. h. einer Gate-Source-Spannung, bzw. als ein (elektrisches) Potential des Steuerungsanschlusses (Gate-Potential) ausgeführt. Insbesondere wird das Ansteuerungssignal durch Nutzung der Potentialtrennvorrichtung, d. h. der potentialfreien Ansteuerung der Schaltelemente, zumindest nahezu konstant jeweils auf ein erstes Niveau (für den eingeschalteten Zustand der Schaltelemente) und/oder auf ein zweites Niveau (für den ausgeschalteten Zustand der Schaltelemente) gehalten. Die Umschaltung zwischen dem ersten und dem zweiten Niveau kann dabei dadurch erfolgen, dass die Potentialtrennvorrichtung durch eine Kontrollvorrichtung angesteuert wird, bspw. durch unterschiedliche Spannungen eingangsseitig an der Potentialtrennvorrichtung.The control signal is preferably implemented as a voltage between the control connection (gate) and the input connection (source), ie a gate-source voltage, or as an (electrical) potential of the control connection (gate potential). In particular, the control signal is kept at least almost constantly at a first level (for the switched-on state of the switching elements) and / or at a second level (for the switched-off state of the switching elements) by using the potential separation device, ie the floating control of the switching elements. The switchover between the first and the second level can take place in that the potential separation device is controlled by a control device, for example by different voltages on the input side of the potential separation device.

Von weiterem Vorteil kann vorgesehen sein, dass die Schaltelemente jeweils als Transistor, vorzugsweise als Feldeffekttransistor, bevorzugt als MOSFET, ausgeführt sind, sodass vorzugsweise durch ein Schalten der jeweiligen Schaltelemente anhand des Ansteuerungssignals ein Stromfluss zwischen dem Eingangsanschluss und einem Ausgangsanschluss des jeweiligen Schaltelements in jeweils einer Richtung beeinflusst wird, wobei bevorzugt hierzu der Steuerungsanschluss der jeweiligen Schaltelemente elektrisch mit der Potentialtrennvorrichtung verbunden ist. Dies hat insbesondere den Vorteil, dass derartige Schaltelemente, insbesondere MOSFETs, eine hohe Einschaltgeschwindigkeiten (Slew-Rate) und eine geringe Kapazität am Gate-Anschluss aufweisen, sodass die Schaltverluste deutlich reduziert werden können. Bspw. sind die Schaltelemente als N-Kanal MOSFETs ausgeführt. Insbesondere kann eine elektrische Verbindung der Steuerungsanschlüsse mit der Potentialtrennvorrichtung auch indirekt über weitere Bauelemente ausgeführt sein.A further advantage can be provided that the switching elements are each designed as a transistor, preferably as a field effect transistor, preferably as a MOSFET, so that a current flow between the input terminal and an output terminal of the respective switching element in each case by switching the respective switching elements on the basis of the control signal Direction is influenced, with the control connection of the respective switching elements preferably being electrically connected to the potential separation device for this purpose. This has the particular advantage that such switching elements, in particular MOSFETs, have a high switch-on speed (slew rate) and a low capacitance at the gate connection, so that the switching losses can be significantly reduced. For example, the switching elements are designed as N-channel MOSFETs. In particular, an electrical connection between the control connections and the potential separation device can also be implemented indirectly via further components.

Vorteilhaft ist es zudem, wenn die Potentialtrennvorrichtung einen ersten Anschluss umfasst, welcher elektrisch (z. B. indirekt, ggf. über wenigstens ein Kontrollelement, wie einem Transistor) mit den Steuerungsanschlüssen der Schaltelemente verbunden ist, und einen zweiten Anschluss umfasst, welcher elektrisch (insbesondere direkt und/oder über eine zweite Masse) mit den Eingangsanschlüssen der Schaltelemente verbunden ist, um vorzugsweise für das Ansteuerungssignal eine Potentialdifferenz zwischen dem ersten und zweiten Anschluss zu erzeugen. Dies ermöglicht insbesondere die Erzeugung einer entsprechenden (Source-Drain-) Spannung der Schaltelemente zum schnellen und zuverlässigen Schalten.It is also advantageous if the potential separation device comprises a first connection which is electrically (e.g. indirectly, possibly via at least one control element, such as a transistor) connected to the control connections of the switching elements, and a second connection which is electrically ( in particular directly and / or via a second ground) is connected to the input connections of the switching elements in order to preferably generate a potential difference between the first and second connection for the control signal. This enables in particular the generation of a corresponding (source-drain) voltage of the switching elements for fast and reliable switching.

Es kann optional möglich sein, dass die Schaltelemente derart (zumindest teilweise) in den Lastkreis integriert sind, dass sie eine voneinander unterschiedliche Stromsperrrichtung im Lastkreis aufweisen, insbesondere durch eine entsprechende unterschiedliche Ausrichtung der Schaltelemente bzw. einer parasitären Diode (zwischen einem Trägermaterial und einem Ausgangsanschluss) der Schaltelemente, sodass vorzugsweise unterschiedliche Halbwellen einer Versorgungsspannung des Lastkreises sperrbar sind. Damit kann zuverlässig eine Wechselspannung zum Betrieb des Heizelements gesteuert werden.It may optionally be possible for the switching elements to be (at least partially) integrated into the load circuit in such a way that they have different current blocking directions in the load circuit, in particular through a correspondingly different alignment of the switching elements or a parasitic diode (between a carrier material and an output connection ) of the switching elements, so that preferably different half-waves of a supply voltage of the load circuit can be blocked. An alternating voltage for operating the heating element can thus be reliably controlled.

Vorteilhafterweise kann bei der Erfindung vorgesehen sein, dass eine Kontrollvorrichtung zur Heizregelung vorgesehen ist, um vorzugsweise eine elektrische Aktivierung der Potentialtrennvorrichtung zur Erzeugung des Ansteuerungssignals durchzuführen, sodass bevorzugt die Schaltelemente hochfrequent durch das Ansteuerungssignal ansteuerbar sind, insbesondere mit einer Schaltfrequenz (im hochfrequenten Bereich) über 2 kHz oder über 10 kHz oder über 20 kHz. Bspw. kann dabei die Kontrollvorrichtung (in dem Last- bzw. einem Steuerkreis) mit einer ersten Masse verbunden sein, vorzugsweise mit welcher auch der Lastkreis verbunden ist. Insbesondere kann sich die erste Masse von einer zweiten Masse unterscheiden, mit welcher der Ansteuerungskreis verbunden ist, wobei bevorzugt die Potentialtrennvorrichtung die Potentialtrennung zwischen Last- (bzw. Steuerkreis) und Ansteuerungskreis durchführt, und/oder ein Potential des Lastkreises bzw. Steuerkreises galvanisch zu einem Potential des Ansteuerungskreises trennt.Advantageously, it can be provided in the invention that a control device for heating regulation is provided in order to preferably carry out an electrical activation of the potential separation device for generating the control signal, so that the switching elements can preferably be controlled at high frequency by the control signal, in particular with a switching frequency (in the high-frequency range) above 2 kHz or above 10 kHz or above 20 kHz. For example, the control device (in the load or a control circuit) can be connected to a first ground, preferably to which the load circuit is also connected. In particular, the first ground can differ from a second ground to which the control circuit is connected, the potential separation device preferably performing the potential separation between the load (or control circuit) and the control circuit, and / or a potential of the load circuit or control circuit galvanically to one Disconnects the potential of the control circuit.

Es kann von Vorteil sein, wenn im Rahmen der Erfindung der Lastkreis das Heizelement umfasst oder mit dem Heizelement elektrisch (lösbar) verbindbar ist, wobei das Heizelement vorzugsweise als Dickschichtheizung ausgeführt ist, und bevorzugt in einen Rührgefäß einer Küchenmaschine integriert ist und/oder integrierbar ist. Bspw. kann das Heizelement Teil des erfindungsgemäßen Heizsystems sein oder separat davon ausgeführt sein. Entsprechend kann der Lastkreis als offener Stromkreis ausgeführt sein, welcher durch das Verbinden mit dem Heizelement geschlossen wird. Insbesondere können Heizsystem und Heizelement lösbar miteinander verbindbar ausgeführt sein. Vorzugsweise kann das Heizelement mit (elektrischen) Verbindungselementen verbunden sein, welche eine lösbare (elektrische) Verbindung zu (elektrischen) Gegenverbindungselementen des Heizsystems ermöglichen. Insbesondere kann das Heizelement in ein Rührgefäß einer Küchenmaschine integriert sein, wobei das Rührgefäß bspw. lösbar in die Küchenmaschine befestigbar und/oder integrierbar ausgeführt ist. Des Weiteren kann das Heizsystem in einem stationären Teil der Küchenmaschine integriert sein, welches bspw. das Rührgefäß aufnehmen kann. Dies ermöglicht eine flexible Handhabung des Heizelements und der Küchenmaschine.It can be advantageous if, within the scope of the invention, the load circuit includes the heating element or can be electrically (detachably) connected to the heating element, the heating element preferably being designed as a thick-film heater and preferably being and / or integrable in a mixing vessel of a kitchen appliance . For example, the heating element can be part of the heating system according to the invention or can be designed separately therefrom. Accordingly, the load circuit can be designed as an open circuit, which is closed by being connected to the heating element. In particular, the heating system and heating element can be designed to be detachably connectable to one another. The heating element can preferably be connected to (electrical) connecting elements which enable a detachable (electrical) connection to (electrical) counter-connecting elements of the heating system. In particular, the heating element can be integrated into a mixing vessel of a kitchen appliance, the mixing vessel being designed, for example, to be detachable and / or integratable in the kitchen appliance. Furthermore, the heating system can be integrated in a stationary part of the kitchen appliance, which, for example, can accommodate the mixing vessel. This enables flexible handling of the heating element and the kitchen appliance.

Von weiterem Vorteil kann vorgesehen sein, dass der Lastkreis eine Spannungsquelle, insbesondere eine Wechselspannungsquelle, zur Bereitstellung des Wechselstroms des Lastkreises umfasst, welche vorzugsweise über die Schaltelemente elektrisch (seriell) mit dem Heizelement verbunden ist und/oder verbindbar ist, insbesondere um eine elektrische Leistung an das Heizelement zu übertragen, sodass durch die Schaltelemente in Abhängigkeit von dem Ansteuerungssignal die Leistungsübertragung steuerbar, insbesondere schaltbar, ist. Damit kann die Leistung des Heizelements zuverlässig und schnell gesteuert werden.A further advantage can be provided that the load circuit comprises a voltage source, in particular an alternating voltage source, for providing the alternating current of the load circuit, which is preferably connected electrically (in series) via the switching elements is and / or can be connected to the heating element, in particular to transmit electrical power to the heating element, so that the power transmission can be controlled, in particular switched, by the switching elements as a function of the control signal. This enables the output of the heating element to be controlled reliably and quickly.

Optional kann es vorgesehen sein, dass die Potentialtrennvorrichtung derart mit den Schaltelementen elektrisch verbunden ist, dass durch die Potentialtrennvorrichtung bei Bereitstellung eines Ansteuerungssignals (direkt) eine zumindest nahezu konstante Spannung zwischen dem jeweiligen Steuerungsanschluss, insbesondere einem Gate-Anschluss, und dem jeweiligen Eingangsanschluss, insbesondere einem Source-Anschluss, erzeugbar ist, vorzugsweise wenigstens nahezu unabhängig von einer Polung des Wechselstroms und/oder von einer Spannung zwischen Ausgangsanschlüssen der Schaltelemente im Normalbetrieb. Damit kann gewährleistet werden, dass auch bei der negativen Halbwelle die Heizleistung zuverlässig geschaltet wird.Optionally, it can be provided that the potential separation device is electrically connected to the switching elements in such a way that, when a control signal is provided (directly), the potential separation device creates an at least almost constant voltage between the respective control connection, in particular a gate connection, and the respective input connection, in particular a source connection, can be generated, preferably at least almost independently of a polarity of the alternating current and / or of a voltage between output connections of the switching elements in normal operation. This ensures that the heating power is switched reliably even with the negative half-wave.

Es kann optional möglich sein, dass der Ansteuerungskreis einen Energieübertrager, vorzugsweise eine eigene Energiequelle und/oder ein Schaltnetzteil und/oder einen AC/DC Wandler (d. h. Gleichrichter), umfasst, um vorzugsweise die Stromversorgung des Ansteuerungskreises bereitzustellen, und bevorzugt die Potentialtrennvorrichtung zur Erzeugung des Ansteuerungssignals mit Energie zu versorgen. Bspw. kann der Energieübertrager dabei mit einer ersten Masse verbunden sein, mit welcher auch der Lastkreis verbunden ist. Insbesondere kann der Energieübertrager eine davon unterschiedliche zweite Masse für den Ansteuerungskreis bereitstellen, insbesondere durch eine Durchführung einer Potentialtrennung. Dies hat den Vorteil, dass die Ansteuerung der Schaltelemente besonders zuverlässig erfolgen kann. Bevorzugt sind dabei AC/DC-Wandler (manchmal auch als AC/DC-Converter bezeichnet) Gleichrichter, die Wechselstrom in Gleichstrom verwandeln.It may optionally be possible that the control circuit comprises an energy transmitter, preferably its own energy source and / or a switched-mode power supply and / or an AC / DC converter (ie rectifier), in order to preferably provide the power supply for the control circuit, and preferably the potential separation device for generation to supply the control signal with energy. For example, the energy transmitter can be connected to a first ground to which the load circuit is also connected. In particular, the energy transmitter can provide a second mass different therefrom for the control circuit, in particular by implementing a potential separation. This has the advantage that the switching elements can be controlled particularly reliably. AC / DC converters (sometimes also referred to as AC / DC converters) rectifiers that convert alternating current into direct current are preferred.

Ferner ist es optional vorgesehen, dass die Potentialtrennvorrichtung als ein Optokoppler ausgeführt ist. Dieser umfasst bspw. einen Sender, wie eine Leuchtdiode, und/oder einen Empfänger, wie eine Photodiode. Dies hat den Vorteil, dass zuverlässig ein Ansteuerungssignal potentialfrei erzeugt werden kann.Furthermore, it is optionally provided that the potential separation device is designed as an optocoupler. This includes, for example, a transmitter, such as a light-emitting diode, and / or a receiver, such as a photodiode. This has the advantage that a trigger signal can be generated reliably in a potential-free manner.

Gemäß einer weiteren Möglichkeit kann bei dem erfindungsgemäßen Heizsystem vorgesehen sein, dass die Potentialtrennvorrichtung eine erste Trenneinheit, insbesondere eine erste Wicklung, im Ansteuerungskreis und eine zweite Trenneinheit, insbesondere eine zweite Wicklung, im Lastkreis umfasst, wobei vorzugsweise durch die zweite Trenneinheit, insbesondere zweite Wicklung, für das Ansteuerungssignal eine Potentialdifferenz in Abhängigkeit von einem Spannungssignal an der ersten Trenneinheit, vorzugsweise ersten Wicklung, erzeugbar ist. Dies stellt eine weitere Möglichkeit zur zuverlässigen Erzeugung des Ansteuerungssignals dar.According to a further possibility, it can be provided in the heating system according to the invention that the potential separation device comprises a first separation unit, in particular a first winding, in the control circuit and a second separation unit, in particular a second winding, in the load circuit, preferably through the second separation unit, in particular a second winding , a potential difference can be generated for the control signal as a function of a voltage signal at the first separating unit, preferably the first winding. This represents a further possibility for reliable generation of the control signal.

Besonders bevorzugt ist es dabei denkbar, dass die Eingangsanschlüsse auf einem gemeinsamen Source-Potential liegen, und vorzugsweise über die Potentialtrennvorrichtung mit den Steuerungsanschlüssen verbunden sind, insbesondere sodass durch das Ansteuerungssignal ein Ausschalten der Schaltelemente bewirkbar ist, um sowohl bei einer negativen als auch einer positiven Halbwelle einer Spannungsversorgung im Lastkreis den Stromfluss zu sperren. Dies ermöglicht einen zuverlässigen Betrieb des Heizelelements.Particularly preferably, it is conceivable that the input connections are at a common source potential and are preferably connected to the control connections via the potential separation device, in particular so that the control signal can be used to switch off the switching elements in order to avoid both a negative and a positive Half-wave of a voltage supply in the load circuit to block the current flow. This enables reliable operation of the heating element.

Ein weiterer Vorteil kann im Rahmen der Erfindung erzielt werden, wenn wenigstens eine der nachfolgenden Anordnungen vorgesehen sind:

  • die Potentialtrennvorrichtung und eine Spannungsquelle des Lastkreises sind jeweils direkt mit einem gemeinsamen Massepotential verbunden,
  • die Potentialtrennvorrichtung, insbesondere ein (ausgangsseitiger) erster Anschluss der Potentialtrennvorrichtung, ist über wenigstens einen ersten Widerstand und/oder wenigstens einem Kontrollelement mit dem ersten Schaltelement und über wenigstens einen zweiten Widerstand und/oder wenigstens einem (ggf. weiteren) Kontrollelement mit dem zweiten Schaltelement verbunden,
  • die Potentialtrennvorrichtung, insbesondere (ausgangsseitig) ein erster Anschluss der Potentialtrennvorrichtung, ist über wenigstens einen dritten Widerstand mit einem Source-Potential der Schaltelemente verbunden, wobei vorzugsweise der dritte Widerstand sehr viel größer als der erste und zweite Widerstand ist.
Another advantage can be achieved within the scope of the invention if at least one of the following arrangements are provided:
  • the potential separation device and a voltage source of the load circuit are each directly connected to a common ground potential,
  • the potential separation device, in particular a (output-side) first connection of the potential separation device, is connected to the first switching element via at least one first resistor and / or at least one control element and via at least one second resistor and / or at least one (possibly further) control element to the second switching element connected,
  • the potential separation device, in particular (on the output side) a first connection of the potential separation device, is connected to a source potential of the switching elements via at least one third resistor, the third resistor preferably being much greater than the first and second resistors.

Die Erfindung umfasst auch allgemein ein Haushaltsgerät, wie z. B. eine Küchenmaschine, mit der erfindungsgemäßen Heizsystem zum Betreiben eines Heizelementes.The invention also generally includes a household appliance, such as. B. a food processor, with the heating system according to the invention for operating a heating element.

Ebenfalls Gegenstand der Erfindung ist ein Verfahren zum Betreiben eines Heizelements, insbesondere bei einer Küchenmaschine. Hierbei ist bevorzugt vorgesehen, dass ein Lastkreis mit dem Heizelement und ein (insbesondere vom Lastkreis separat ausgeführter) Ansteuerungskreis vorgesehen sind. Insbesondere können dabei die nachfolgenden Schritte durchgeführt werden, vorzugsweise nacheinander oder in beliebiger Reihenfolge, wobei ggf. auch einzelne Schritte wiederholt ausgeführt werden können:

  • Ansteuern einer mit dem Ansteuerungskreis verbundenen Potentialtrennvorrichtung durch eine Kontrollvorrichtung in Abhängigkeit von einer Ansteuerungsvorgabe, sodass vorzugsweise bei einer ersten Ansteuerungsvorgabe ein erstes Ansteuerungssignal (insbesondere potentialfrei) erzeugt wird, und bei einer zweiten Ansteuerungsvorgabe ein zweites Ansteuerungssignal (insbesondere potentialfrei) erzeugt wird,
  • Anlegen des erzeugten Ansteuerungssignals an wenigstens zwei Schaltelemente, sodass vorzugsweise ein Wechselstrom im Lastkreis zum Heizelement für beide Stromrichtungen gesperrt wird, wenn das erzeugte Ansteuerungssignal das erste Ansteuerungssignal ist, und für beide Stromrichtungen freigegeben wird, wenn das erzeugte Ansteuerungssignal das zweite Ansteuerungssignal ist.
The invention also relates to a method for operating a heating element, in particular in a kitchen appliance. In this case, it is preferably provided that a load circuit with the heating element and a control circuit (in particular executed separately from the load circuit) are provided. In particular, the following steps can be carried out, preferably one after the other or in any order, with individual steps also being able to be carried out repeatedly if necessary:
  • Activation of a potential separation device connected to the activation circuit by a control device as a function of an activation specification, so that a first activation signal (in particular potential-free) is generated with a first activation specification and a second activation signal (in particular potential-free) is generated with a second activation specification,
  • Applying the generated control signal to at least two switching elements, so that an alternating current in the load circuit to the heating element is preferably blocked for both current directions if the generated control signal is the first control signal, and is released for both current directions if the generated control signal is the second control signal.

Damit bringt das erfindungsgemäße Verfahren die gleichen Vorteile mit sich, wie sie ausführlich mit Bezug auf ein erfindungsgemäßes Heizsystem beschrieben worden sind. Zudem kann das Verfahren geeignet sein, ein erfindungsgemäßes Heizsystem zu betreiben.The method according to the invention thus has the same advantages as have been described in detail with reference to a heating system according to the invention. In addition, the method can be suitable for operating a heating system according to the invention.

Bspw. kann die Potentialtrennvorrichtung eingangsseitig mit einem Steuerkreis und/oder Lastkreis, und insbesondere einer Kontrollvorrichtung, und ausgangsseitig mit dem Ansteuerungskreis, und insbesondere mit den Schaltelementen, elektrisch verbunden sein. Die Verbindung zum jeweiligen Schaltelement kann dabei dazu dienen, das Anlegen des erzeugten Ansteuerungssignals durchzuführen, indem das Ansteuerungssignal über die Verbindung an die Schaltelemente übertragen wird.For example, the potential separation device can be electrically connected on the input side to a control circuit and / or load circuit, and in particular a control device, and on the output side to the control circuit, and in particular to the switching elements. The connection to the respective switching element can serve to apply the generated control signal by transmitting the control signal to the switching elements via the connection.

Es kann dabei vorgesehen sein, dass bei zumindest einem der Ansteuerungssignale eine (zumindest nahezu konstante) Spannung als jeweiliges Ansteuerungssignal erzeugt wird, bspw. eine Source-Gate-Spannung für die Schaltelemente. Bspw. kann dabei die Ansteuerungsvorgabe digital (zwischen-)gespeichert sein, um durch die Kontrollvorrichtung ausgewertet zu werden. Die Ansteuerungsvorgabe ist bspw. spezifisch für eine Solltemperatur eines Mediums, welches durch das Heizelement erhitzt werden soll. Auch ist es denkbar, dass die Ansteuerungsvorgabe als Steuerungsinformation ausgeführt ist, welche bspw. eine Schaltfrequenz bestimmt, mit welcher das Heizelement angesteuert werden soll. Des Weiteren kann es möglich sein, dass die Ansteuerungsvorgabe in Abhängigkeit von einer Erfassung eines Temperatursensors bestimmt wird. Bspw. kann eine erste Ansteuerungsvorgabe eine erste Steuerungsinformation sein (welche bspw. ein Sperren des Wechselstroms indiziert) und die zweite Ansteuerungsvorgabe eine zweite Steuerungsinformation sein (welche bspw. ein Freigeben des Wechselstroms indiziert).It can be provided that an (at least almost constant) voltage is generated as the respective control signal for at least one of the control signals, for example a source-gate voltage for the switching elements. For example, the Control specification can be digitally (temporarily) stored in order to be evaluated by the control device. The control specification is, for example, specific for a target temperature of a medium that is to be heated by the heating element. It is also conceivable that the control specification is implemented as control information which, for example, determines a switching frequency with which the heating element is to be controlled. Furthermore, it may be possible for the control specification to be determined as a function of a detection by a temperature sensor. For example, a first control specification can be first control information (which, for example, indicates blocking of the alternating current) and the second control specification can be second control information (which, for example, indicates enabling of the alternating current).

Ebenfalls Gegenstand der Erfindung ist eine Küchenmaschine zur zumindest teilweise automatischen Zubereitung von Lebensmitteln, mit:

  • wenigstens einem Rührgefäß, welches zumindest ein Heizelement aufweist,
  • wenigstens einen Temperatursensor zur Erfassung einer Temperatur am Rührgefäß.
The invention also relates to a food processor for the at least partially automatic preparation of food, with:
  • at least one stirred vessel, which has at least one heating element,
  • at least one temperature sensor for detecting a temperature on the stirred vessel.

Hierbei ist insbesondere denkbar, dass ein erfindungsgemäßes Heizsystem vorgesehen ist, um eine Heizregelung des Heizelementes anhand der erfassten Temperatur durchzuführen, insbesondere um so eine Ansteuerungsvorgabe zu bestimmen. Damit bringt die erfindungsgemäße Küchenmaschine die gleichen Vorteile mit sich, wie sie ausführlich mit Bezug auf ein erfindungsgemäßes Heizsystem und/oder ein erfindungsgemäßes Verfahren beschrieben worden sind. Zudem kann die Küchenmaschine geeignet sein, gemäß einem erfindungsgemäßen Verfahren betrieben zu werden.It is particularly conceivable here that a heating system according to the invention is provided in order to carry out a heating regulation of the heating element on the basis of the detected temperature, in particular in order to determine an actuation specification in this way. The kitchen appliance according to the invention thus brings the same advantages as have been described in detail with reference to a heating system according to the invention and / or a method according to the invention. In addition, the kitchen appliance can be suitable to be operated according to a method according to the invention.

Es kann ferner bei der erfindungsgemäßen Küchenmaschine möglich sein, dass eine Waage vorgesehen ist, welche das Medium, insbesondere wenigstens ein im Rührgefäß vorliegendes Lebensmittel, wiegen kann. Eine dadurch ermittelte Gewichtsinformation des Lebensmittels kann bspw. über eine Anzeigevorrichtung, wie einem Display bzw. einem Touchscreen, einem Benutzer der Küchenmaschine angezeigt werden. Weiter kann es denkbar sein, dass auf der Anzeigevorrichtung auch die erfasste Temperatur des Temperatursensors und/oder eine eingestellte Heizleistung angezeigt wird. Es kann möglich sein, dass eine Heizregelung des Heizsystems durch den Benutzer an einer Eingabevorrichtung der Küchenmaschine, wie dem Touchscreen, beeinflusst bzw. aktiviert wird. Dies ermöglicht eine sehr komfortable Bedienung der Küchenmaschine.It can furthermore be possible in the case of the kitchen appliance according to the invention that scales are provided which can weigh the medium, in particular at least one food present in the mixing vessel. Weight information of the food that is determined in this way can, for example, be displayed to a user of the food processor via a display device such as a display or a touchscreen. Furthermore, it can be conceivable that the recorded temperature of the temperature sensor and / or a set heating power is also displayed on the display device. It may be possible for the heating system to be controlled by the user on a Input device of the food processor, such as the touchscreen, is influenced or activated. This enables very convenient operation of the food processor.

Weitere Vorteile, Merkmale und Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung, in der unter Bezugnahme auf die Zeichnungen Ausführungsbeispiele der Erfindung im Einzelnen beschrieben sind. Dabei können die in den Ansprüchen und in der Beschreibung erwähnten Merkmale jeweils einzeln für sich oder in beliebiger Kombination erfindungswesentlich sein. Es zeigen schematisch:

Figur 1
eine Darstellung von Teilen eines erfindungsgemäßen Heizsystems,
Figur 2
eine weitere Darstellung von Teilen eines erfindungsgemäßen Heizsystems,
Figur 3
eine schematische Darstellung von Teilen einer erfindungsgemäßen Küchenmaschine.
Further advantages, features and details of the invention emerge from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. They show schematically:
Figure 1
a representation of parts of a heating system according to the invention,
Figure 2
a further representation of parts of a heating system according to the invention,
Figure 3
a schematic representation of parts of a food processor according to the invention.

In den nachfolgenden Figuren werden für die gleichen technischen Merkmale auch von unterschiedlichen Ausführungsbeispielen die identischen Bezugszeichen verwendet.In the following figures, the same reference numerals are used for the same technical features from different exemplary embodiments.

In Fig. 1 sind schematisch Teile eines erfindungsgemäßen Heizsystems 200 gezeigt. Weiter dient Fig. 1 zur Veranschaulichung eines erfindungsgemäßen Verfahrens 100. Es ist ein Lastkreis 201 und ein Ansteuerungskreis 202 gekennzeichnet, wobei es sich hier vorzugsweise um Schaltkreise mit voneinander getrennten Massen und/oder (zumindest annähernd) getrennte galvanische Schaltkreise 201, 202 handelt. Neben dem Ansteuerungskreis 202 kann optional ein Steuerkreis vorgesehen sein, welcher bspw. die Kontrollvorrichtung 220 umfasst und mit einer Potentialtrennvorrichtung 270 elektrisch verbunden ist. Alternativ kann die Kontrollvorrichtung 220 auch direkt in den Lastkreis 201 integriert sein. Es können die Potentialtrennvorrichtung 270 (eingangsseitig, z. B. im Steuerkreis) und/oder die Kontrollvorrichtung 220 und/oder der Lastkreis 201 mit einem ersten Massepotential GND (erste Masse) verbunden sein (wie in Fig. 1 beispielhaft dargestellt ist). Ein davon unterschiedliches zweites Massepotential SGND (zweite Masse, welche zumindest nicht direkt mit GND verbunden ist) kann optional mit einem zweiten Anschluss 270.2 der Potentialtrennvorrichtung 270 und/oder mit einem Eingangsanschluss 250.3 zweier Schaltelemente 250 elektrisch verbunden sein (wie auch in Fig. 2 näher dargestellt ist). Um eine Stromversorgung für den Ansteuerungskreis 202 bereitzustellen, kann bspw. ein Energieübertrager 280 vorgesehen sein, welcher bspw. das zweite Massepotential SGND bereitstellen kann (dies ist ebenfalls näher in Fig. 2 gezeigt).In Fig. 1 parts of a heating system 200 according to the invention are shown schematically. Further serves Fig. 1 to illustrate a method 100 according to the invention. A load circuit 201 and a control circuit 202 are identified, whereby these are preferably circuits with separate grounds and / or (at least approximately) separate galvanic circuits 201, 202. In addition to the control circuit 202, a control circuit can optionally be provided which, for example, comprises the control device 220 and is electrically connected to a potential separation device 270. Alternatively, the control device 220 can also be integrated directly into the load circuit 201. The potential separation device 270 (on the input side, e.g. in the control circuit) and / or the control device 220 and / or the load circuit 201 can be connected to a first ground potential GND (first ground) (as in FIG Fig. 1 is shown as an example). A different second ground potential SGND (second ground which is at least not directly connected to GND) can optionally be connected to a second connection 270.2 of the potential separation device 270 and / or to an input connection 250.3 of two switching elements 250 must be electrically connected (as also in Fig. 2 is shown in more detail). In order to provide a power supply for the control circuit 202, an energy transmitter 280, for example, can be provided which, for example, can provide the second ground potential SGND (this is also shown in more detail in FIG Fig. 2 shown).

Die Schaltelemente 250, d. h. ein erstes Schaltelement 250a und ein demgegenüber anders ausgerichtetes zweites Schaltelement 250b, können jeweils z. B. als Transistor bzw. MOSFETs ausgeführt sein. Aufgrund einer jeweiligen parasitären Diode 250.1 ist es notwendig, beide Schaltelemente 250 in einer antiseriellen Verschaltung vorzusehen, um eine Wechselspannung U bzw. Wechselstrom I einer Spannungsquelle 260, insbesondere Wechselspannungsquelle 260, vollständig (d. h. in beide Stromrichtungen) zu sperren.The switching elements 250, i. H. a first switching element 250a and a second switching element 250b, which is oriented differently, can each be, for. B. be designed as a transistor or MOSFETs. Due to a respective parasitic diode 250.1, it is necessary to provide both switching elements 250 in an anti-series connection in order to completely block an alternating voltage U or alternating current I of a voltage source 260, in particular alternating voltage source 260 (i.e. in both current directions).

Die einzelnen Schaltelemente 250 können einen Eingangsanschluss 250.3 mit einem Source-Potential S und einen Ausgangsanschluss 250.4 mit einem Drain-Potential D und einen Steuerungsanschluss 250.2 mit einem Ansteuerungspotential G, insbesondere Gate-Potential G, aufweisen. Die Potentialtrennvorrichtung 270 kann ausgangsseitig (am Ansteuerungskreis 202) insbesondere wenigstens einen ersten (Ausgangs-) Anschluss 270.1 und den zweiten (Ausgangs-) Anschluss 270.2 aufweisen, welche jeweils mit dem Ansteuerungskreis 202 verbunden sind. Auch können eingangsseitig weitere (Eingangs-) Anschlüsse vorgesehen sein, welche bspw. kontrollvorrichtungsseitig bzw. steuerungskreisseitig verbunden sind. Beispielhaft sind eingangsseitig auch eine erste Trenneinheit 270.3 (z. B. erste Wicklung 270.3) und ausgangsseitig eine zweite Trenneinheit 270.4 (z. B. zweite Wicklung 270.4) der Potentialtrennvorrichtung 270 gezeigt, die die galvanische Trennung verdeutlichen, wobei es sich bei der Potentialtrennvorrichtung 270 auch um einen Optokoppler oder dergleichen handeln kann, welcher somit keine Wicklungen aufweisen muss.The individual switching elements 250 can have an input connection 250.3 with a source potential S and an output connection 250.4 with a drain potential D and a control connection 250.2 with a control potential G, in particular gate potential G. The potential separation device 270 can have on the output side (on the control circuit 202) in particular at least one first (output) connection 270.1 and the second (output) connection 270.2, which are each connected to the control circuit 202. Further (input) connections can also be provided on the input side, which are connected, for example, on the control device side or on the control circuit side. A first separating unit 270.3 (e.g. first winding 270.3) and on the output side a second separating unit 270.4 (e.g. second winding 270.4) of the potential separation device 270 are also shown by way of example on the input side, which illustrate the galvanic separation can also be an optocoupler or the like, which therefore does not have to have any windings.

Der erste Anschluss 270.1 der Potentialtrennvorrichtung 270 ist z. B. über einen ersten Widerstand R1 und/oder über wenigstens ein Kontrollelement 230 mit dem Steuerungsanschluss 250.2 des ersten Schaltelements 250a und über einen zweiten Widerstand R2 und/oder über wenigstens ein (ggf. weiteres) Kontrollelement 230 mit dem Steuerungsanschluss 250.2 des zweiten Schaltelements 250b elektrisch verbunden. Optional kann ein dritter Widerstand R3 vorgesehen sein, welcher z. B. mit einem hohen Widerstandswert ausgeführt ist, um die Stabilität der Schaltung zu erhöhen. Der zweite Anschluss 270.2 der Potentialtrennvorrichtung 270 ist bspw. (z. B. direkt und/oder über ein zweites Massepotential) mit den Eingangsanschlüssen 250.3 der Schaltelemente 250, d. h. mit dem Source-Potential S, elektrisch verbunden. Auf diese Weise kann ein gemeinsames Bezugspotential S für das Ansteuerungssignal A geschaffen werden und/oder das Ansteuerungssignal A an die Schaltelemente 250 gemäß einem erfindungsgemäßen Verfahren 100 angelegt werden. Insbesondere dient dabei das Ansteuerungssignal A (bspw. als Gate-Source-Spannung) zur Ansteuerung der Schaltelemente 250, d. h. zur Überführung der Schaltelemente 250 von einem offenen Zustand, in welchem der Stromfluss eines Stroms I im Lastkreis 201 unterbunden ist, in einen geschlossenen Zustand, in welchem der Stromfluss zugelassen wird, und/oder umgekehrt. Auf diese Weise kann die Heizleistung eines Heizelements 210, insbesondere einer Dickschichtheizung 210, im Lastkreis 201 zuverlässig gesteuert und/oder geregelt werden.The first connection 270.1 of the potential separation device 270 is z. B. via a first resistor R1 and / or via at least one control element 230 with the control connection 250.2 of the first switching element 250a and via a second resistor R2 and / or via at least one (possibly further) control element 230 with the control connection 250.2 of the second switching element 250b electrically connected. Optionally, a third resistor R3 can be provided, which z. B. with a high Resistance is designed to increase the stability of the circuit. The second connection 270.2 of the potential separation device 270 is electrically connected, for example (for example directly and / or via a second ground potential) to the input connections 250.3 of the switching elements 250, ie to the source potential S. In this way, a common reference potential S can be created for the control signal A and / or the control signal A can be applied to the switching elements 250 according to a method 100 according to the invention. In particular, the control signal A (e.g. as gate-source voltage) is used to control the switching elements 250, ie to transfer the switching elements 250 from an open state, in which the flow of a current I in the load circuit 201 is prevented, to a closed state , in which the flow of current is allowed, and / or vice versa. In this way, the heating power of a heating element 210, in particular a thick-film heater 210, in the load circuit 201 can be reliably controlled and / or regulated.

In Fig. 2 ist die in Fig. 1 beschriebene oder eine ähnliche Schaltungskonfiguration eines Heizsystems 200 schematisch gezeigt. Hierbei ist eine Energieversorgungsvorrichtung 290 für den Ansteuerungskreis 202 gezeigt, welche bspw. eine Spannungsquelle X1 aufweist, die z. B. eine Netzspannung liefert und/oder die der Spannungsquelle 260 in Fig. 1 entspricht. Diese kann bspw. mit einem Energieübertrager 280 verbunden sein, welcher z. B. als Gleichrichter die Spannungsversorgung für den Ansteuerungskreis 202 bereitstellt. Hierdurch kann auch ein zweites Massepotential SGND bereitgestellt werden, welches sich von einem ersten Massepotential GND des Lastkreises 201 unterscheidet, d. h. insbesondere galvanisch getrennt davon ausgeführt ist. Weiter kann hierdurch bzw. durch den Energieübertrager 280 eine erste Spannung V1 bereitgestellt werden, welche z. B. zum Betrieb wenigstens eines Kontrollelements 230 genutzt wird. Das oder die Kontrollelemente 230 sind bspw. als Halbleiterschalter, bspw. als Transistor oder MOSFETs, ausgeführt, um das Ansteuerungssignal A zu erzeugen, insbesondere an einem Ansteuerungspotential G der Schaltelemente 250. Die potentialfreie Erzeugung des Ansteuerungssignals A erfolgt bspw. dadurch, dass das wenigstens eine Kontrollelement 230 durch die Potentialtrennvorrichtung 270 angesteuert wird und/oder die erste Spannung galvanisch getrennt erzeugt wird und/oder die Schaltelemente 250 jeweils mit dem zweiten Massepotential SGND verbunden sind. Die Potentialtrennvorrichtung 270 wird bspw. durch eine zweite Spannung V2 betrieben, welche durch den Energieübertrager 280 bereitgestellt werden kann.In Fig. 2 is the in Fig. 1 or a similar circuit configuration of a heating system 200 is shown schematically. Here, an energy supply device 290 for the control circuit 202 is shown, which, for example, has a voltage source X1, which z. B. supplies a mains voltage and / or that of the voltage source 260 in Fig. 1 corresponds to. This can, for example, be connected to an energy transmitter 280, which z. B. provides the voltage supply for the control circuit 202 as a rectifier. As a result, a second ground potential SGND can also be provided, which differs from a first ground potential GND of the load circuit 201, that is to say, in particular, is designed to be electrically isolated from it. Furthermore, a first voltage V1 can be provided by this or by the energy transmitter 280, which z. B. is used to operate at least one control element 230. The control element (s) 230 are, for example, a semiconductor switch, for example a transistor or MOSFET, in order to generate the control signal A, in particular at a control potential G of the switching elements 250 a control element 230 is controlled by the potential separation device 270 and / or the first voltage is generated in an electrically isolated manner and / or the switching elements 250 are each connected to the second ground potential SGND. The potential separation device 270 is, for example a second voltage V2 operated, which can be provided by the energy transmitter 280.

Eine Initiierung des potentialfrei erzeugten Ansteuerungssignals A erfolgt bspw. durch eine Kontrollvorrichtung 220, welche insbesondere die Potentialtrennvorrichtung 270 ansteuert. Die Kontrollvorrichtung 220 stellt dazu bspw. eine Spannungsversorgung U270 für die Potentialtrennvorrichtung 270 und/oder ein Kontrollsignal KS an einem Eingang der Potentialtrennvorrichtung 270 bereit.The activation signal A generated in a potential-free manner is initiated, for example, by a control device 220, which in particular activates the potential separation device 270. For this purpose, the control device 220 provides, for example, a voltage supply U270 for the potential separation device 270 and / or a control signal KS at an input of the potential separation device 270.

In Fig. 3 ist schematisch ein Rührgefäß 2 einer Küchenmaschine 1 gezeigt. Dabei ist ein Medium 20 im Rührgefäß 2 mit einem Rührwerk 3 dargestellt, wobei das Medium 20 durch ein Heizelement 210 erhitzt werden kann. Das Heizelement 210 ist bspw. in einen Rührgefäß-Boden 2.1 integriert, wobei das Heizelement 210 dann auch optional separat von der Küchenmaschine 1 ausgeführt sein kann. Bspw. kann das Rührgefäß 2 lösbar mit dem Heizsystem 200 der Küchenmaschine 1 verbunden werden, wobei auch elektrische Kontakte zur Integration des Heizelements 210 in den Lastkreis 201 vorgesehen sein können. Die Ansteuerung des Heizelements 210 wird dann bspw. durch eine Kontrollvorrichtung 220 gesteuert, welche bspw. ebenfalls mit dem Lastkreis 201 verbunden ist und/oder in eine Elektronik der Küchenmaschine 1 integriert ist. Zur Regelung der Ansteuerung des Heizelements 210 können bspw. Temperaturwerte durch die Erfassung eines Temperatursensor 4 durch die Kontrollvorrichtung 220 ausgewertet werden, wobei der Temperatursensor 4 bspw. in das Rührgefäß integriert ist.In Fig. 3 a mixing vessel 2 of a food processor 1 is shown schematically. A medium 20 is shown in the stirred vessel 2 with a stirrer 3, the medium 20 being able to be heated by a heating element 210. The heating element 210 is integrated, for example, in a mixing vessel base 2.1, with the heating element 210 then optionally also being able to be designed separately from the kitchen appliance 1. For example, the mixing vessel 2 can be detachably connected to the heating system 200 of the kitchen appliance 1, it also being possible for electrical contacts to be provided for integrating the heating element 210 into the load circuit 201. The activation of the heating element 210 is then controlled, for example, by a control device 220 which, for example, is also connected to the load circuit 201 and / or is integrated into an electronics of the kitchen appliance 1. To regulate the activation of the heating element 210, for example, temperature values can be evaluated by the detection of a temperature sensor 4 by the control device 220, the temperature sensor 4 being integrated, for example, in the stirred vessel.

Die voranstehende Erläuterung der Ausführungsformen beschreibt die vorliegende Erfindung ausschließlich im Rahmen von Beispielen. Selbstverständlich können einzelne Merkmale der Ausführungsformen, sofern technisch sinnvoll, frei miteinander kombiniert werden, ohne den Rahmen der vorliegenden Erfindung zu verlassen.The above explanation of the embodiments describes the present invention exclusively in the context of examples. Of course, individual features of the embodiments can be freely combined with one another, provided that they are technically sensible, without departing from the scope of the present invention.

BezugszeichenlisteList of reference symbols

11
KüchenmaschineFood processor
22
RührgefäßStirring vessel
2.12.1
Rührgefäß-BodenMixing vessel bottom
33
RührwerkAgitator
44th
TemperatursensorTemperature sensor
2020th
Mediummedium
100100
VerfahrenProcedure
200200
HeizsystemHeating system
201201
LastkreisLoad circuit
202202
AnsteuerungskreisControl circuit
210210
Heizelement, DickschichtheizungHeating element, thick film heating
220220
KontrollvorrichtungControl device
230230
KontrollelementControl element
250250
SchaltelementSwitching element
250.1250.1
parasitäre Diodeparasitic diode
250.2250.2
SteuerungsanschlussControl connection
250.3250.3
EingangsanschlussInput connector
250.4250.4
AusgangsanschlussOutput connector
250a250a
erstes Schaltelementfirst switching element
250b250b
zweites Schaltelementsecond switching element
260260
Spannungsquelle, WechselspannungsquelleVoltage source, AC voltage source
270270
PotentialtrennvorrichtungPotential separation device
270.1270.1
erster Anschlussfirst connection
270.2270.2
zweiter Anschlusssecond connection
270.3270.3
erste Wicklungfirst winding
270.4270.4
zweite Wicklungsecond winding
280280
Energieübertrager, Energiequelle, SchaltnetzteilEnergy transmitter, energy source, switched-mode power supply
290290
EnergieversorgungsvorrichtungPower supply device
AA.
AnsteuerungssignalControl signal
DD.
Drain-PotentialDrain potential
GG
Ansteuerungspotential, Gate-PotentialControl potential, gate potential
II.
elektrischer Strom, Wechselstromelectric current, alternating current
KSKS
KontrollsignalControl signal
GNDGND
erstes Massepotentialfirst ground potential
SGNDSGND
zweites Massepotentialsecond ground potential
R1R1
erster Widerstandfirst resistance
R2R2
zweiter Widerstandsecond resistance
R3R3
dritter Widerstandthird resistance
SS.
Source-Potential, gemeinsames BezugspotentialSource potential, common reference potential
UU
Spannungtension
U270U270
Spannungsversorgung für 270Power supply for 270
X1X1
Spannungsversorgung, entspricht ggf. 260Power supply, if necessary corresponds to 260

Claims (14)

  1. Heating system (200) for operating a heating element (210), in particular in a food processor (1), comprising:
    - a load circuit (201) comprising at least two electronic switching elements (250) each comprising a control terminal (250.2) and a respective input terminal (250.3), wherein the switching elements (250) are anti-serially interconnected to influence an alternating current (I) to the heating element (210),
    - a control circuit (202) to initiate an electric control signal (A) to control the switching elements (250),
    - a potential separating device (270) for providing the control signal (A) at the control terminals (250.2) in such a way that an electric potential at the input terminals (250.3) forms a common reference potential (S) of the switching elements (250) for the control signal (A).
  2. Heating system (200) according to claim 1,
    characterized in that
    the load circuit (201) and the control circuit (202) are electrically connected to different grounds, wherein a first ground potential (GND) is connected to the load circuit (201), and a second ground potential (SGND) is connected to the control circuit (202), preferably electrically connected to the input terminals (250.3), and particularly preferably forming the common reference potential (S).
  3. Heating system (200) according to claim 1 or 2,
    characterized in that
    the switching elements (250) are each designed as a transistor, preferably as a field-effect transistor, preferably as a MOSFET, so that a current flow between the input terminal (250.3) and an output terminal (250.4) of the respective switching element (250) is influenced in one direction in each case by switching the respective switching elements (250) using the control signal (A), wherein the control terminal (250.2) of the respective switching elements (250) is electrically connected to the potential separating device (270) for switching.
  4. Heating system (200) according to any one of the preceding claims,
    characterized in that
    the potential separating device (270) comprises a first terminal (270.1), which is electrically connected to the control terminals (250.2) of the switching elements (250), and a second terminal (270.2), which is electrically connected to the input terminals (250.3) of the switching elements (250), in order to generate a potential difference between the first and second terminals (270.1, 270.2) for the control signal (A).
  5. Heating system (200) according to any one of the preceding claims,
    characterized in that
    the switching elements (250) are integrated into the load circuit (201) in such a way that they comprise a current blocking direction in the load circuit (201) which differs from one another, in particular by a corresponding alignment of a parasitic diode (250.1) between a carrier material and an output terminal (250.4) of the switching elements (250), so that different half-waves of a supply voltage of the load circuit (201) can be blocked.
  6. Heating system (200) according to any one of the preceding claims,
    characterized in that
    a controlling device (220) for heating regulation is provided in order to carry out electric activation of the potential separating device (270) for a potential-free generation of the control signal (A), so that the switching elements (250) can be controlled at high frequency by the control signal (A), in particular at a switching frequency above 2 kHz.
  7. Heating system (200) according to any one of the preceding claims,
    characterized in that
    the load circuit (201) comprises to the heating element (210) or can be connected to the heating element (210), which is designed as a thick-film heater and can preferably be integrated in a stirring vessel (2) of a food processor (1).
  8. Heating system (200) according to any one of the preceding claims,
    characterized in that
    the load circuit (201) comprises a voltage source (260), in particular an alternating voltage source (260), for providing the alternating current (I) of the load circuit (201), which can be electrically connected to the heating element (210) via the switching elements (250) in order to transmit electrical power to the heating element (210), so that the power transmission can be controlled, in particular switched, by the switching elements (250) depending on the control signal (A).
  9. Heating system (200) according to any one of the preceding claims,
    characterized in that
    the potential separating device (270) is connected to the switching elements (250) in such a way that, when the control signal (A) is provided, an at least almost constant voltage can be generated directly by the potential separating device (270) between the respective control terminal (250.2), in particular a gate terminal, and the respective input terminal (250.3), in particular a source terminal, preferably at least almost independently of a polarity of the alternating current (I) and/or of a voltage between output terminals (250.4) of the switching elements (250) in normal operation.
  10. Heating system (200) according to any one of the preceding claims,
    characterized in that
    the control circuit (202) comprises an energy transformer (280), preferably a dedicated energy source (280) and/or a switched-mode power supply (280) and/or an AC/DC converter (280), to provide the current supply to the control circuit (202), and preferably to supply energy to the potential separating device (270) for generating the control signal (A).
  11. Heating system (200) according to any one of the preceding claims,
    characterized in that
    the potential separating device (270) is designed as an opto-coupler.
  12. Heating system (200) according to any one of the preceding claims,
    characterized in that
    at least one of the following arrangements are provided:
    - the potential separating device (270) and a voltage source (260) of the load circuit (201) are each directly connected to a common ground potential (GND),
    - the potential separation device (270), in particular a first terminal (270.1) of the potential separation device (270), is connected to the first switching element (250a) via at least one first resistor (R1) and to the second switching element (250b) via at least one second resistor (R2),
    - the potential separation device (270), in particular a first terminal (270.1) of the potential separation device (270), is connected to a source potential (S) of the switching elements (250) via at least one third resistor, wherein the third resistor (R3) is very much larger than the first and second resistors (R1, R2).
  13. Method for operating a heating element (210), in particular in a food processor (1), wherein a load circuit (201) with the heating element (210) and a control circuit (202) are provided, wherein the following steps are performed:
    - Control of a potential separating device (270) connected to the control circuit (202) by a controlling device (220) depending on a control specification, so that a first control signal (A) is generated potential-free in the case of a first control specification, and a second control signal (A) is generated potential-free in the case of a second control specification,
    - Application of the generated control signal (A) to at least two switching elements (250) so that an alternating current (I) in the load circuit (201) to the heating element (210) is blocked for both current directions when the generated control signal (A) is the first control signal (A) and is enabled for both current directions when the generated control signal (A) is the second control signal (A), wherein a heating system (200) according to any one of the preceding claims is operated.
  14. Food processor (1) for at least partially automatic preparation of food, comprising:
    - at least one stirring vessel (2), which comprises at least one heating element (210),
    - at least one temperature sensor (4) for acquiring a temperature at the stirring vessel (2),
    characterized in that
    a heating system (200) according to any one of claims 1 to 12 is provided for performing a heating regulation of the heating element (210) based on the acquired temperature.
EP17200251.1A 2017-11-07 2017-11-07 Heating system for operating a heating element Active EP3481143B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP17200251.1A EP3481143B1 (en) 2017-11-07 2017-11-07 Heating system for operating a heating element

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Application Number Priority Date Filing Date Title
EP17200251.1A EP3481143B1 (en) 2017-11-07 2017-11-07 Heating system for operating a heating element

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EP3481143A1 EP3481143A1 (en) 2019-05-08
EP3481143B1 true EP3481143B1 (en) 2021-07-14

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Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4500802A (en) * 1982-06-21 1985-02-19 Eaton Corporation Three terminal bidirectional source to source FET circuit
DE4446796C2 (en) * 1994-12-24 1998-01-29 Rowenta Werke Gmbh Circuit arrangement for an electric toaster, fed by a mains voltage
CA2427039C (en) * 2003-04-29 2013-08-13 Kinectrics Inc. High speed bi-directional solid state switch
JP4127131B2 (en) * 2003-06-25 2008-07-30 松下電工株式会社 Light control device
JP2012153912A (en) * 2011-01-24 2012-08-16 Ss Alloy Kk Electric heating machine
US10122359B2 (en) * 2015-08-07 2018-11-06 Semiconductor Components Industries, Llc Integrated circuit control of anti-series switches

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