EP3291645A1 - Four à micro-ondes - Google Patents

Four à micro-ondes Download PDF

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Publication number
EP3291645A1
EP3291645A1 EP17187497.7A EP17187497A EP3291645A1 EP 3291645 A1 EP3291645 A1 EP 3291645A1 EP 17187497 A EP17187497 A EP 17187497A EP 3291645 A1 EP3291645 A1 EP 3291645A1
Authority
EP
European Patent Office
Prior art keywords
door
generating unit
microwave
microwave oven
switch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP17187497.7A
Other languages
German (de)
English (en)
Inventor
Ewald Bayer
Marcus Frank
Konrad SCHÖNEMANN
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.)
EGO Elektro Geratebau GmbH
Original Assignee
EGO Elektro Geratebau GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EGO Elektro Geratebau GmbH filed Critical EGO Elektro Geratebau GmbH
Publication of EP3291645A1 publication Critical patent/EP3291645A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/6414—Aspects relating to the door of the microwave heating apparatus
    • H05B6/6417—Door interlocks of the microwave heating apparatus and related circuits

Definitions

  • the invention relates to a microwave oven, as it is advantageously used and prepared for the preparation of food, so as an electric household appliance.
  • Known and common microwave ovens are equipped with a magnetron as a microwave generating unit. They may also be equipped with a semiconductor microwave generating unit, so that semiconductor elements for generating microwaves can be used, see EP 3035773 A1 , The latter represents a new technique, which can also be called Solid State Cooking.
  • the invention has for its object to provide a microwave oven mentioned above, with the problems of the prior art can be avoided and it is particularly possible to ensure the reliability of the microwave oven at the same time low production costs.
  • the microwave oven has a cavity or a microwave oven muffle. It has a door by means of which the cavity is closed in a closed state and which leaves the cavity accessible in an open state.
  • the microwave oven further includes a microwave generating unit for generating microwaves to be dispensed into the cavity.
  • it has at least one door switch, which is designed to detect the closed or open state of the door or at least reliably detect whether the door is completely closed.
  • the door switch is adapted to interrupt a power supply of the microwave generating unit when the door is opened or not completely closed. This is necessary to prevent the generation of microwaves when the door is open, as this may otherwise result in damage to health.
  • the approval requirements for such devices are very high.
  • a shutdown device which is connected to the at least one door switch and the microwave generating unit. It is connected in such a way that it immediately switches off the microwave generation unit in response to an open or no longer completely closed state of the door detected by the door switch and / or immediately ends the generation of microwaves.
  • the shutdown device can in particular take into account the fact that in modern microwave generating units, in particular the aforementioned semiconductor microwave generating units, capacitors are frequently present. These provide in a pure interrupting the power supply to the microwave generating unit that, despite the lack of power supply or power supply for a certain time continue to generate microwaves, even with the door open. This can lead to a health hazard.
  • the microwave oven preferably has a plurality of door switches or a plurality of door switches, in particular up to three door switches.
  • the security can be further increased because in case of failure of a door switch yet another door switch or several other door switch are present, which detect a possibly open state of the door.
  • the door switches can be interconnected in different combinations and interconnected.
  • All of the embodiments of the invention mentioned herein can be implemented with at least one door switch and correspondingly also with a plurality of door switches.
  • the at least one door switch is connected in a line of an AC power supply of the microwave generating unit.
  • the power supply of the microwave generating unit can be interrupted immediately, which represents an additional security, even if this measure does not have the same speed as the described effect of the defeat device.
  • the door switch is adapted to interrupt a line to the shutdown device in the open state of the door.
  • both the AC power supply can be switched off as well as a corresponding signal to the shutdown device are triggered.
  • the shutdown device may be designed to detect such a broken line, which arises when the door is open.
  • the turn-off device can have an input-side differentiating element and an integrator connected downstream of the differentiating element in order to generate a binary signal.
  • an embodiment has proven to be useful for typical situations when turning off a semiconductor microwave generating unit.
  • a smoothing circuit and / or a rectifier circuit can be connected upstream in order to better adapt the turn-off device to use with alternating current. This results in a better usable or evaluable signal.
  • the turn-off device has a signal line which is led directly into the microwave generating unit.
  • the direct shutdown of the microwave generating unit or the generation of microwaves can be done better and above all more direct, because it goes faster.
  • the shutdown device for switching off the microwave generating unit act on a primary side and / or on a switching regulator and / or on a secondary side of a switching power supply.
  • the microwave generating unit according to an embodiment may advantageously be a semiconductor microwave generating unit.
  • the advantage comes particularly to bear in that the switch-off device is interconnected and typically its functionality does not depend on the functioning of software components. This considerably facilitates a security certification or approval since the software does not have to be included in it.
  • the shutdown device for switching off a semiconductor microwave generating unit acts on a high frequency part of the semiconductor microwave generating unit.
  • This may in particular be at a gate voltage of a preamplifier and / or at a gate voltage of a power amplifier and / or at one or more amplifier stages and / or at an enable input of an oscillator module and / or at a high frequency switch and / or at a pulse width modulation generation Be (PWM).
  • PWM pulse width modulation generation Be
  • the PWM can go into the already mentioned oscillator module. In such places, a particularly advantageous, in particular rapid shutdown can be achieved.
  • the points described herein, at which the shut-off device can act to switch off can be combined with one another in any desired manner.
  • the shutdown device can thus act at different or at several of the described points or even at other locations. All such combinations and sub-combinations are considered part of the disclosure of this application or invention.
  • the door switch is connected to one or a plurality of inputs of the turn-off device.
  • the turn-off device is connected so that it switches off the microwave generating unit when it responds to the fact that at least at one of the inputs a respective predefined signal is applied.
  • the inputs can be interconnected so that they are logically rounded or grounded.
  • the respective predefined signal required for this purpose can be, for example, 0 or 1 for all inputs. However, different predefined signals can be used.
  • a temperature sensor With at least one input, a temperature sensor can be connected. Thus, temperature values of components can be monitored, so that when too high a temperature of a component, a shutdown can be triggered. At least one input may also be connected to an output terminal of a microcontroller or another programmable unit. As a result, a microcontroller or another programmable unit can be given the opportunity to influence whether microwave generation should take place or not. For example, it can be achieved that when closing a door, a microcontroller or another programmable unit can specify that the microwave generation should start later, ie with a time delay.
  • An input can also be connected to at least one coupler structure for detecting reflected microwave power.
  • a reflected microwave power can be detected and used for controlling the microwave generation.
  • the microwave generation can be reduced or advantageously ended.
  • the microwave oven has a so-called input-side primary interlock switch and / or a so-called output-side monitor switch as a door switch.
  • the microwave oven has a secondary interlock switch downstream of the primary interlock switch as a door switch, which shorts two lines when the door is open, so that when a supply voltage is applied, a fuse connected in one of the lines would open or burn out if the Primary interlock switch would not have opened.
  • the secondary interlock switch shorts the two lines when the door is opened. Then the fuse blows, because due to the malfunction of the Primary Interlock Switch still a supply voltage is applied. In normal operation is due to the proper function When the secondary interlock switch is opened or switched over to short-circuit the cables, the primary interlock switch no longer supplies any power so that the fuse does not open or blow.
  • the microwave generating unit is designed so that it immediately stops the generation of microwaves when switched off.
  • an electrical separation of capacities can be made.
  • a particularly high level of security can be achieved.
  • FIG. 1 a circuit of a microwave oven according to the invention.
  • Fig. 1 shows a circuit 10 of a microwave oven 50 according to the invention according to embodiments of the invention.
  • different embodiments are shown, which show different possible embodiments of how a turn-off device can act on a microwave generating unit to terminate the microwave generation. These are denoted by the lower case letters a) to g). These designs can be used alone or combined with each other.
  • the installation of the circuit 10 in a microwave oven poses no problems for the skilled person.
  • the circuit 10 has a power supply unit (PSU) 20, which serves for the direct power supply of a semiconductor microwave generating unit 40.
  • PSU power supply unit
  • the PSU 20 is connected to an AC power supply whose lines are labeled L and N.
  • the semiconductor microwave generating unit 40 when energized and a shutdown device 30 described below is not active, generates microwaves which are discharged into a cavity of the microwave oven 50 in a conventional manner. It has an oscillator module 42, a preamplifier 44 and a power amplifier 46.
  • a fuse F1 is initially connected. Subsequently, up to three door switches can be provided or interconnected.
  • three door switches in the form of a primary interlock switch S1, a secondary interlock switch S2 and a monitor switch S3 are interconnected.
  • the three door switches S1, S2, S3 are actuated by a door of the microwave oven 50, wherein they can be opened when opening the door advantageously in an order S1, S2, S3 and immediately one behind the other.
  • the secondary interlock switch S2 is connected in such a way that it not only interrupts the line L in the state with the door open, but also short-circuits it to the line N.
  • the fuse F1 would immediately burn or open and open so that the power supply would be interrupted until the fuse F1 was replaced or activated .
  • switching contact k (a) In the line N is further a switching contact (switching contact) k (a) connected, which can provide an additional interruption.
  • switching contact k (b) is also connected on the output side to the PSU 20 in a line. Also with this an interruption can be achieved.
  • the PSU 20 directly supplies the semiconductor microwave generating unit 40 with electric power, which is represented by the fact that the two right-handed lines are each provided with an arrow. They lead to the semiconductor microwave generating unit 40, which is shown only in the embodiments d) to g). In these embodiments, the microwave oven 50 is shown.
  • the circuit 10 further includes the shutdown device 30 already mentioned above.
  • the shutdown device 30 is connected as shown to the two lines L and N. If at least one of the already mentioned three door switches S1, S2 or S3 opens, thus also the input side of the shutdown device 30 is affected, i. in particular set to a zero level.
  • the switch-off device 30 In order to convert such a signal into a switching signal, the switch-off device 30 has a differentiating element 32 and an integrating element 34.
  • the shutdown device 30 can act on different components, which is shown as possible embodiments with the lowercase letters a) to g) and will be described below.
  • the shutdown device 30 acts on a switching regulator 25 of the PSU 20.
  • a power supply of the semiconductor microwave generating unit 40 can be interrupted.
  • the turn-off device 30 acts on a primary side of a switching power supply K (a).
  • the shutdown device 30 acts on a relay on a secondary side of a switching power supply K (b).
  • the turn-off device 30 acts on an enable input of the oscillator module 42 of the semiconductor microwave generating unit 40.
  • the turn-off device 30 acts on a gate voltage of the preamplifier 44 or on one or more amplifier stages of the preamplifier 44 of the semiconductor microwave generating unit 40.
  • the turn-off device 30 acts on a gate voltage of the power amplifier 46 of the semiconductor microwave generating unit 40.
  • the turn-off device 30 acts on a pulse width modulation PWM, which enters the already mentioned oscillator module 42.
  • the turn-off device 30 acts in each case in the semiconductor microwave generating unit 40, only just at different locations. The important thing is the result of the direct or rapid shutdown of the generation of microwaves.
  • a shutdown can be realized, which is faster and / or which, above all, a generation of microwaves terminated immediately. This increases the safety of the microwave oven 50.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Electric Ovens (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
EP17187497.7A 2016-08-31 2017-08-23 Four à micro-ondes Withdrawn EP3291645A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102016216411.2A DE102016216411A1 (de) 2016-08-31 2016-08-31 Mikrowellenofen

Publications (1)

Publication Number Publication Date
EP3291645A1 true EP3291645A1 (fr) 2018-03-07

Family

ID=59699538

Family Applications (1)

Application Number Title Priority Date Filing Date
EP17187497.7A Withdrawn EP3291645A1 (fr) 2016-08-31 2017-08-23 Four à micro-ondes

Country Status (2)

Country Link
EP (1) EP3291645A1 (fr)
DE (1) DE102016216411A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0031589A2 (fr) * 1979-12-26 1981-07-08 Matsushita Electric Industrial Co., Ltd. Appareil de chauffage pour aliments muni d'un circuit synthétiseur de la voix
US4321445A (en) * 1980-01-28 1982-03-23 Whirlpool Corporation Door latch interlock system for microwave oven
EP0318645A1 (fr) * 1987-11-28 1989-06-07 Kabushiki Kaisha Toshiba Système de cuisson composite ayant un dispositif de chauffage par micro-ondes et un dispositif de chauffage par induction
JP2011146143A (ja) * 2010-01-12 2011-07-28 Panasonic Corp マイクロ波処理装置
EP3035773A1 (fr) * 2014-12-17 2016-06-22 E.G.O. ELEKTRO-GERÄTEBAU GmbH Generateur de micro-ondes et four a micro-ondes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0031589A2 (fr) * 1979-12-26 1981-07-08 Matsushita Electric Industrial Co., Ltd. Appareil de chauffage pour aliments muni d'un circuit synthétiseur de la voix
US4321445A (en) * 1980-01-28 1982-03-23 Whirlpool Corporation Door latch interlock system for microwave oven
EP0318645A1 (fr) * 1987-11-28 1989-06-07 Kabushiki Kaisha Toshiba Système de cuisson composite ayant un dispositif de chauffage par micro-ondes et un dispositif de chauffage par induction
JP2011146143A (ja) * 2010-01-12 2011-07-28 Panasonic Corp マイクロ波処理装置
EP3035773A1 (fr) * 2014-12-17 2016-06-22 E.G.O. ELEKTRO-GERÄTEBAU GmbH Generateur de micro-ondes et four a micro-ondes

Also Published As

Publication number Publication date
DE102016216411A1 (de) 2018-03-01

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