ES2351293B1 - INDUCTION HEATING AND PROCEDURE APPARATUS FOR YOUR OPERATION. - Google Patents

Abstract

Induction heating apparatus and procedure for commissioning. # An induction heating apparatus with an inductor for the transmission of heating energy is proposed by a heating oscillation to a heating element to be heated, with a bridge connection for the activation of the inductor, where by means of a first switch a unit for the correction of the power factor is connectable between the bridge connection and the inductor. Likewise, a procedure for the start-up of the induction heating apparatus is specified.

Description

Heating device by induction and procedure for operation.

The invention relates to an induction heating apparatus, as well as a method for putting the induction heating apparatus into operation.

An induction heating apparatus is known, by way of example, in the form of an induction cooking field, in which a metal cooking battery is heated by inductively generated eddy currents.

Thus, from EP 1 708 545 A2 it is known to transmit through an induction cooking field with an upper surface of ceramic hob energy in the form of an alternating magnetic field to the base of the cooking battery, which is transformed into an encasement. ceramic hob is a coil through which current flows, which generates an alternating magnetic field. This induces eddy currents by induction in a metal bowl placed above, which heats the metal of the iron, from there, heats the contents by thermal transmission.

In this, it is disadvantageous that heating of the non-ferromagnetic cooking battery is not possible without problems and may, for example, conduct audible resonances for the user.Movement of the cooking battery may also occur due to the repulsive force that is generated. Also, during the heating of the non-ferromagnetic cooking battery, high electrical losses occur.

The task of the invention consists in avoiding the disadvantages mentioned above and, in particular, specifying an induction heating device that allows efficient operation of a ferromagnetic cooking battery, as well as a non-ferromagnetic cooking battery.

This task is solved according to the characteristics of the independent claims. Further improvements of the invention are also extracted from the dependent claims.

For the solution of the task, an induction heating device is specified

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With an inductor for the transmission of heating energy by a heating oscillation to a heating element to be heated,

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with a bridge connection for inductor activation,

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where, by means of a first switch, a unit for the correction of the power factor can be connected between the bridge connection and the inductor.

In this, it should be noted that the unit mentioned above for the correction of the power factor has at least one inductance and / or at least one capacitor. The inductance can comprise here in particular a transformer.

It should also be noted that in the bridge connection it can be any converter or inverter for the activation of the inductor.Amode of example, inverters can be used by means of the complete bridge inductors.

In this case, it is advantageous that, by means of the unit for the correction of the power factor, both the ferromagnetic material firing battery and the ferromagnetic material firing battery can be heated efficiently by means of this inducer, which can be used to reduce the losses of the raised rises, so that a heating device is used for induction heating with a fixed induction battery. non-ferromagnetic cooking battery.

Another advantage is that, through the connectivity of the unit for the correction of the power factor, the induction heating apparatus can always be operated at an advantageous operating point and, consequently, the construction elements can be set for a smaller operating range. Therefore, a more advantageous induction heating device manufacturing is achieved.

An improvement is that, by means of the first switch, the unit for correction of the power factor is at least partially disconnectable.

As an example, the unit for the correction of the power factor can be disconnected, in particular, galvanically separated, partially totalized. This is preferably produced in the event that a ferromagnetic cooking battery has been used on the induction heating apparatus.

Another improvement is that, in the case of a largely non-ferromagnetic material cooking battery, the unit for the correction of the power factor is connectable and / or, in the case of a largely ferromagnetic material cooking battery, the unit for the correction of the power factor, it can be disconnected, especially bypass.

In this, it should be noted that the rotation "firing battery of (non) ferromagnetic material" refers in particular to a cooking battery base. Through a type base, they are induced by the heating device by swirling induction currents, and a heating of the base of the cooking battery.

In this case, it is advantageous that, by means of the unit for the correction of the power factor, it is possible to react appropriately to different operating states (modes), that is, depending on the cooking battery material (ferromagnetic or not), it can be achieved by connecting or disconnecting the unit for correction of the power factor an effective operation of the induction heating apparatus.

In particular, it is an improvement that the unit for the correction of the power factor has a transformer and at least one capacitor.

By means of the transformer, the current through the inductor can be effectively reduced for the non-ferromagnetic cooking battery, or the voltage in the inductor can be increased. Through the capacitor, an improvement of the load power factor is produced.

Also a refinement of the unit for the correction of the power factor present in an input that, through a primary side of the transformer, is connected to a node,

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where the node is connectable through a serial connection, comprising a secondary side of the transformer and the capacitor, through the first switch with a first inductor connection, and

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where the node is connected to a second inductor connection.

This enables an advantageous embodiment of the unit for the correction of the power factor. In the configuration described, the unit for the correction of the power factor can preferably be connected or disconnected. Correspondingly, an effective extension of the available induction heating devices is possible.

Also, an improvement is that the node is connectable with the second connection of the conductor through a second switch, where the first switch and the second switch are essentially switchable simultaneously.

Accordingly, advantageously, the unit for the power factor correction can be connected or disconnected galvanically. For the realization with two switches, the transformer may have a lower primary inductance.

Alternatively, the primary coil of the transformer may have a high inductance, so that the second switch can be suppressed.

In the framework of further improvement, the switch comprises at least one of the following construction elements:

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an electronic switch, especially a transistor, a mosfet or an IGBT,

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a mechanical switch,

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a relay

In this, it should be noted that in the mentioned switch it may be the first switch and / or the second switch.

A further improvement is that the switch is connectable in a manner dependent on a constitution of the cooking battery.

Therefore, a connection, good, disconnection, automated unit for the correction of the power factor can advantageously take place depending on which constitution (ferromagnetic material is not) the cooking battery is present. It can also be determined to automatically evaluate if there is no cooking battery.

One con fi guration is that the constitution of the heating element be determinable by an inductance and / or by a power factor.

Preferably, a corresponding signal can be acquired and properly evaluated by regulating.

An alternative embodiment consists in that the constitution is determinable by means of a command and, by means of the command, the first switch / or the second switch is / is addressable.

Therefore, preferably the control can automatically recognize which constitution has a cooking battery and, depending on it, connect or disconnect the unit automatically for correction of the power factor.

In this, it should be noted that the command may comprise, for example, a computer, especially a microcontroller or a processor.

A next configuration is that the control activates the bridge connection depending on the state of the first switch and / or the second switch.

The command can also preferably be used to activate the bridge connection, for example, depending on a theoretical predetermination of a user (temperature, cooking time, etc.). This activation occurs differently depending on the type of operation (ferromagnetic cooking battery or non-ferromagnetic cooking battery): a dependency of such type (for example, based on a characteristic line or current measurement data) can be taken into account and transferred appropriately by the command.

The aforementioned task is also solved by a procedure for the activation of a heating device by induction as described herein.

An improvement is especially that

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In the case of a largely non-ferromagnetic material cooking battery, the unit for correction of the power factor is connected to and / or

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in the case of a largely ferromagnetic material firing battery, the unit for the correction of the power factor is disconnected, especially bridged.

Also, perfecting the unit for correction of the power factor is automatically connected or disconnected.

Likewise, it is an improvement that determines a constitution of a cooking battery and, consequently, the switch is activated or deactivated.

Below, the examples of implementation of the invention are represented by means of the drawings.

They show:

Fig. 1 an example for a symbolic block diagram of an induction heating device with a unit for power factor correction;

Fig. 2 a schematic connections based on the schematic diagram according to Figure 1;

Fig. 3 a symbolic representation of the inductance L and the PF power factor for the ferromagnetic firing battery, the ferromagnetic firing battery, and there is no cooking battery on the inductor;

Fig. 4 exemplary, two curve progressions for cases where the cooking battery is made of ferromagnetic material, and that the cooking battery is made of non-ferromagnetic material.

The present approach proposes to act, by way of example, in a manner dependent on a constitution, for example, a material, of a cooking battery, an induction heating apparatus in different types of operation.

For this, a unit for the correction of the power factor can be connected at least partially between a bridge connection, for example, an inverter, and an inductor. The unit for the correction of the power factor is preferably configured in such a way as to enable a modification of the power factor depending on the type of operation.

Figure 1 shows an example for a symbolic block diagram of an induction heating apparatus with a unit for correction of the power factor 104.

An alternating supply voltage101 is transformed into a rectifier102 into a continuous voltage, and is inserted through a converter, well, inverter103 (also; inverter or connection) to activate an inductor 105.

In particular, a microcontroller may be provided, by means of which, in a manner dependent on user settings (predetermined heating power), or in a manner dependent on predetermined regulations or types of operation, the inductor 105 is activated via a connection in semipuente or through a complete bridge connection.

It is also possible that a plurality of inductors are provided, or that parts of inductors can also be activated.

The inductor 105 is suitable for the transmission of heating energy by a heating oscillation to a heating element to be heated, for example, to a cooking battery 106.

In Figure 1, between the inverter 103 and the inductor 105 (with connections 111 and 112) the unit for the correction of the power factor 104, which has a transformer T and a capacitor C1, is represented symbolically. Likewise, a first switch S1 is provided, which can switch between contacts B1 and B2, that is, connect the connection 111 of the inductor optionally with contact B1 or with contact B2.

The transformer has a primary coil with connections 107 and 108, and a secondary coil with connections 109 and 110. Inverter 103 is connected to connection 107 and to contact B2 of the first switch S1. The connection 108 of the primary coil is connected to the connection 110 of the secondary coil, as well as the connection 112 of the inductor. Connection 109 of the secondary coil is connected through capacitor C1 to contact B1 of the first switch S1.

The interconnected transformer T can be used effectively to increase the current through the inductor 105, or reduce the voltage in the inductor 105, in case the cooking battery 106 is not made of ferromagnetic material.

Thus, the inverter 103 supplies a supply voltage for the start-up of the inductor 105, the capacitor C1 improves the power factor in the case where it is necessary to heat the ferromagnetic cooking battery (and the first switch S1 is connected to the contact B1) .In this case, the transformer Takes the voltage level for commissioning operation of the inductor 105 so that it is essentially in the range that is otherwise used to heat ferromagnetic cooking battery.

The first switch S1 can be performed as a relay and can be

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connect the connection 111 of the inductor 105 with the contact B1 for the use of a non-ferromagnetic cooking battery, or

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connect the connection 111 of the inductor 105 with the contact B2 for the use of a ferromagnetic cooking battery.

Therefore, advantageously, different metal firing batteries can be heated efficiently by the induction heating apparatus proposed herein.

In particular, it is possible that the setting of the first switch S1 takes place automatically, or it can be routed through a computer (for example, a microprocessor or a microcontroller). Thus, it can be determined automatically that the cooking battery is essentially ferromagnetic or essentially non-ferromagnetic. For example, Figure 3 shows a symbolic representation of the PF power factor inductance for cases

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the sphero-magnetic cooking battery (case 301),

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the ferromagnetic firing battery (case 302), and

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there is no cooking battery on the inductor (case 303).

Therefore, the computer can automatically determine in a dependent manner such behavior if a cooking battery is on the inductor, or if this cooking battery is ferromagnetic or not. A setting of the first switch S1 can take place correspondingly.

The transformer is preferably sized in a way that can be made available to the energy needed at most for the case of the non-ferromagnetic firing battery.For the configuration of the transformer, the following parameters are preferably considered, among others, maximum power, maximum voltage, switching frequency, as well as the resonances

The inverter 103 is operated differently according to the type of operation, that is, for example, depending on the position of the first switch S1. Accordingly, depending on the material of the cooking battery 106, the activation of the inverter can occur correspondingly with different switching frequencies. The figure 4 shows exemplary progressions in the case of the cooking battery being made of ferromagnetic material, and that the cooking battery is made of non-ferromagnetic material. abscissa shows the switching frequency divided by the resonance frequency, and the ordinate shows the power divided by the power at the resonance point.

Figure 2 shows a schematic connections based on the schematic diagram according to Figure 1.

The supply voltage Vl, (with connections 202 and 203) is applied to two power transistors npn Q1, Q2, as well as to two diodes D1, D2: connection 202 of the supply voltage Vl is connected to the collector of transistor Q1, The emitter of transistor Q1 is connected to the collector of transistor Q2, and with a node 204. The emitter of transistor Q2 is connected to connection 203 of the supply voltage Vl. The cathode of the diode D1 is connected to the connection 202 of the alternating supply voltage Vl, the anode of the diode D1 is connected to the node 204y with the cathode of the diode D2. The anode of diode D2 is connected to connection 203 of the alternating supply voltage Vl.

Node 204 is connected to contact B2 of the first switch S1, in addition node 204 is connected to connection 107 of the primary coil of transformer T according to the power factor correction unit

104. Referring to this unit for the correction of the power factor 104, the first switch S1 and the inductor 105, refer to the embodiments of Figure 1. Only the connection 112 of the inductor 105 is connected according to Figure 2 with a central connection of a series of capacitor capacitors C2 and C3, being connected to one of its other ends with two voltage connections. power supply The two capacitors C2 and C3 are preferably sized essentially the same.

Connection 112 is also connected as an input signal with a command 201 which, in an exemplary manner, directs the two transistors Q1, Q2 through their respective base.

For example, by means of the information captured in connection 112, you can determine by setting the cooking battery that is not ferromagnetic. It can also be determined if there is any cooking battery.

The control201 also presents (not shown) command signals, for example, of a user, for example, for the setting of a desired temperature of the induction heating device.It is also possible that the command directs the first switch S1 corresponding to the detected cooking battery (not shown in Figure 2).

Optionally, on route 205, another switch (not shown) could be provided, which is essentially activated together with the first switch S1 such that, in case of connection of connection 111 with contact B2, the second switch S2 interrupt route 205 and, correspondingly, in case of connection of connection 111 with contact B1, route 205 is closed. This has the advantage that, in the case of the ferromagnetic cooking battery, route 205 is physically separated.

To heat the cooking battery, the circuit is directed by controlling the mode of oscillating circuit, and the inductor is generating an oscillating magnetic field. This oscillating magnetic field is produced in the base of the pot set as heating elements in eddy currents that heat the pot base. The pot base temperature can be measured by a temperature sensor, and the measurement can be transmitted to the remote.

The approach proposed here makes it possible to preserve the type of operation for ferromagnetic cooking batteries. In particular, induction heating elements can be extended efficiently and economically only for ferromagnetic cooking batteries.

With the type of operation for non-ferromagnetic cooking batteries, semiconductors of the inverter power, for example, transistors of an inverter bridge, can be effectively directed, and losses can be reduced.

The maximum operating current and the maximum operating voltage for the inductor, as well as the resonance capacities, can be reduced. With this, these components can be sized correspondingly more economically.

With reduced losses of such mode, it is possible to reduce the cost for cooling the induction heating device. This also contributes to the reduction of costs for the induction heating apparatus.

List of reference symbols

Alternating supply voltage 102 Recti fi er 103 Inverter 104

Power factor correction unit 105 Inductor 106 Cooking battery 107, 108 Transformer primary coil connections T 109, 110 Transformer secondary coil connections T 111, 112 Inductor connections 105

201 Knob 202, 203 Connections of the unit with the alternating supply voltage 101 204 Node (center socket between power transistors Q1, Q2) 205 Route between the connection 112 of the inductor unit for correction of the power factor

301 Unloaded area 302 Area of a non-ferromagnetic cooking battery 303 Area of a ferromagnetic cooking battery

Claims (14)

1. Induction heating device

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with an inductor (105) for the transmission of heating energy by a heating oscillation to a heating element to be heated,

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with a bridge connection (103) for inductor activation (105),

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where, by means of a first switch (S1), a unit for the correction of the power factor (104) with at least one capacitor (C1) can be connected to the power connection (103) and the inductor (105).

2.

Induction heating apparatus according to claim 1, wherein, by means of the first switch (S1), the unit for correction of the power factor (104) is at least partially disconnectable.

3.

Induction heating apparatus according to one of the preceding claims, wherein the unit for the correction of the power factor (104) has a transformer (T).

Four.

Induction heating apparatus according to claim 3, wherein the power factor correction unit (104) has an input that, through a primary side of the transformer (T), is connected to a node,

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where the node is connectable through a series connection, comprising a secondary side of the transformer (T) and the capacitor (C1), through the first switch (S1) with a first connection of the inductor (105), and

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where the node is connected to a second inductor connection (105).

5. Heating device by induction according to claim 4, in which the node is connectable with the second connection of the inductor through a second switch (S2), where the first switch (S1) and the second switch are simultaneously switchable. 6. Induction heating apparatus according to one of the preceding claims, wherein the switch (S1, S2) comprises one of the following construction elements:

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an electronic switch, especially a transistor, a mosfet or an IGBT,

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a mechanical switch,

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a relay

7.

Induction heating apparatus according to one of claims 5 or 6, wherein the switch is connectable depending on a constitution of the cooking battery.

8.

Induction heating apparatus according to claim 7, wherein the constitution of the heating element is determinable by an inductance and / or by a power factor.

9.

Apparatus for heating by induction according to one of claims 7 or 8, in which the constitution is determinable by means of a control (201) and, by means of the command, the first switch (S1) and / or the second switch (S2) is / are addressable (s).

10.

Induction heating apparatus according to claim 9, wherein the control (201) activates the bridge connection (Q1, Q2) in a manner dependent on the state of the first switch (S1) and / or the second switch (S2).

eleven.

Procedure for the activation of an induction heating apparatus according to one of the preceding claims, in which

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in the case of a largely non-ferromagnetic material firing battery, the unit for the correction of the power factor is connected and / or

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In the case of a largely ferromagnetic material firing battery, the unit for the correction of the power factor is disconnected, especially bridged.

12.

Method according to claim 11, wherein the unit for the correction of the power factor is automatically switched on or off.

13.

Method according to one of claims 11 or 12, wherein a constitution of a cooking battery is determined and, consequently, the switch is activated or deactivated.

SPANISH OFFICE OF THE PATENTS AND BRAND Application no .: 200900739 SPAIN Date of submission of the application: 11.03.2009 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE 51 Int. Cl.: H05B6 / 06 (01.01.2006) H05B6 / 12 (01.01.2006) RELEVANT DOCUMENTS

Category

Documents cited Claims Affected

X

WO 9832310 A1 (INDUCED ENERGY LTD et al.) 23.07.1998, page 6, line 36 - page 8, 1-13

line 21; figure 4.

TO

EP 1528839 A1 (LG ELECTRONICS INC) 04.05.2005, summary; figure 2; paragraphs [27-33]. 1-13

TO

EP 1414276 A1 (MATSUSHITA ELECTRIC IND CO LTD) 28.04.2004, figures 2,7,9; 1-13

paragraphs [12], [23], [31], [44].

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the date of priority submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims □ for claims no:

Date of realization of the report 14.01.2011

Examiner E. Pina Martínez Page 1/4

REPORT OF THE STATE OF THE TECHNIQUE Application number: 200900739 Minimum documentation searched (classification system followed by classification symbols) H05B Electronic databases consulted during the search (name of the database and, if possible, terms of search used) INVENES, EPODOC, WPI State of the Art Report Page 2/4  WRITTEN OPINION Application number: 200900739 Date of the Written Opinion: 14.01.2011 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims Claims 5, 11-13 1-4, 6-10 IF NOT

Inventive activity (Art. 8.1 LP11 / 1986)

Claims Claims 1-13 IF NOT

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/4  WRITTEN OPINION Application number: 200900739 1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

WO 9832310 A1 (INDUCED ENERGY LTD et al.) 23.07.1998

2. Statement motivated according to articles 29.6 and 29.7 of the Regulations for the execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement D01 is considered the prior art prior to the object of the claims. This document affects the novelty and / or inventive activity of all claims as explained in detail below. Claim 1 Document D01, in terms of claim 1 of the application, describes the following (references in parentheses refer to D01): Induction heating apparatus comprising: -an inductor (L) for the transmission of heating energy by a heating oscillation to an element from heating (P) to heating. -a bridge connection (SW1, SW2) for inductor activation (L), where by means of a switch (RL1) a unit for the correction of the power factor (T) with at least one capacitor (C) is connectable between the bridge connection and the inductor. In view of the foregoing, all the technical elements that make up claim 1 are described in D01, whereby this claim lacks the requirement of novelty according to Art 6.1 of Patent Law 11/86. Claims 2-10 The content of claims 2-4 is also described in D01 (see figure 7), so that these also do not satisfy the requirement of novelty (Art. 6.1 LP). As for claim 5, its content differs from that described in D01 in the presence of a second switch that is not present in the device in D01. However, the incorporation of a switch element whose technical effect is to electrically isolate a certain branch of an electrical circuit is considered sufficiently known in the related art sector, which would not involve the exercise of inventive effort for the person skilled in the art. Accordingly, claim 5 lacks the necessary inventive activity requirement as set forth in Art. 8.1 LP. As for the rest of dependent claims 6-10, the technical characteristics defined therein are disclosed in D01, so they are not new (Art. 6.1 LP). Claims 11-13 The procedure for activating the induction heating apparatus of document D01 differs from the procedure claimed in the following: In the application procedure the power factor correction unit is disconnected when the cooking battery is ferromagnetic and connected when the battery is non-ferromagnetic. In the procedure described in D01 the power correction unit, that is the autotransformer, is always connected and what is varied by the switch RL1 is the ratio of turns between the primary and the secondary, which has the effect of increasing the current and with it the heating power. Thus, by determining the inductance by the CT sensor, the system automatically adjusts the current flowing through the inductor, depending on the type of material that constitutes the cookware. In any case, both solutions are considered equivalent alternatives within the same inventive concept, so that the claims of procedure 11-13 do not meet the requirement of inventive activity within the meaning of Art. 8.1 LP. In conclusion, the application does not satisfy the patentability requirements established in Art. 4.1 LP. State of the Art Report Page 4/4