WO2015114623A1 - An induction heating device - Google Patents

An induction heating device Download PDF

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Publication number
WO2015114623A1
WO2015114623A1 PCT/IL2015/050086 IL2015050086W WO2015114623A1 WO 2015114623 A1 WO2015114623 A1 WO 2015114623A1 IL 2015050086 W IL2015050086 W IL 2015050086W WO 2015114623 A1 WO2015114623 A1 WO 2015114623A1
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Prior art keywords
induction heating
heating device
coil
core
induction
Prior art date
Application number
PCT/IL2015/050086
Other languages
French (fr)
Inventor
Tomer KUJMAN
Original Assignee
Kujman Tomer
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Publication date
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Publication of WO2015114623A1 publication Critical patent/WO2015114623A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2804—Printed windings
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/36—Coil arrangements
    • H05B6/362—Coil arrangements with flat coil conductors
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/36—Coil arrangements
    • H05B6/365—Coil arrangements using supplementary conductive or ferromagnetic pieces
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2804—Printed windings
    • H01F2027/2814—Printed windings with only part of the coil or of the winding in the printed circuit board, e.g. the remaining coil or winding sections can be made of wires or sheets

Definitions

  • the present invention relates to the field of induction heating system. More particularly, the invention relates to a high frequency induction heating coils and a method for providing low-profile Printed Circuit Board (PCB) type coil, with or without an integrated planar transformer.
  • PCB Printed Circuit Board
  • IH Induction Heating
  • the basic electromagnetic phenomenon that induction-heating process relays on is quite simple.
  • a time-variable magnetic field will be produced.
  • the magnetic field will have the same frequency as the coil current.
  • the strength of the magnetic field in a specific point is depending on the current flowing in the induction coil, the number of turns, the coil geometry, and the distance from the coil.
  • the time-variable magnetic field will induce eddy currents in the workpiece located near the coil.
  • Alternating eddy currents produces heat according to Joule effect ( ⁇ ⁇ 2 R) since eddy currents are a direct result of the magnetic flex flowing throw the workpiece the currents in the coil windings needs to be high (or the number of turns) for a fast heating process.
  • AC-AC converters circuit usually includes a step down AC transformer with a high winding turns ratio in order to produce the required high currents. In most cases due to system demands of specific height and width a usage of high number of turns cannot be performed.
  • Another important phenomenon usually called “skin effect” describes the non-uniform current through a conductor when an alternating power source is applied. The current density will decrease from the surface of the conductor towards its center. The layer that the current flows through is called Reference depth or Penetration depth. Reference depth depends on the frequency and material properties as described in Equation (l):
  • Reference depth plays a fundamental role in induction heating theory.
  • the reference depth needed depends on the IH application and can be classified to low, up to 3 kHz! medium, from 3 to 20 kHz! high, from 20 to 100 kHz! and RF, above 100 kHz.
  • the present invention can be applied in all of those areas.
  • IH appliances combine three fundamental parts : high frequency generator (AC-AC converter), high frequency transformer (to enlarge the output currents) and an induction heating coil.
  • high frequency generator AC-AC converter
  • high frequency transformer to enlarge the output currents
  • induction heating coil AC-AC converter
  • - Domestic heating appliances usually use a planar helical coil made of copper wire or high cost copper Litz wire with a shielding Aluminum plate to reduce the EMI radiation.
  • High power industrial appliances usually use a hollow conductor with water cooling systems.
  • Helical windings of conventional magnetic devices have some major disadvantages: • A relatively large profile and therefore only small number of turns can be used, e.g. a domestic planar helical coil made with copper Litz wire for a 3 Kw load can be made of a 16mm 2 Litz wire with an outer radius 10 cm (inner radios is 0, with a total of 13 turns), a 20 Kw Industrial IH appliance a can use a 5 turns helical coil made of hollow copper conductor with a total height of 10 cm, outer radius of 20 cm and an inner radius of 16 cm.
  • IH appliances e.g. a 25 KVA induction-heating appliance will have about 40A input current and up to 1200A output current.
  • a hollow conductors with water cooling circulation in order to decrease the heat generates in the conductor due to high amplitude high frequency currents (and due to the heat radiation from the work piece).
  • This solution is expensive, requires a relatively large space (needs a cooling tank) and does not solve the power losses problem.
  • IH is not new in the industrial market it has not yet fully spread in the industrial market as a heat treatment method due to large initial costs.
  • the present invention proposes a modified planar magnetic system.
  • the windings of planar transformers and inductors are located on flat surfaces (PCB— Printed Circuit Board) extending outward from the core center leg.
  • PCB Printed Circuit Board
  • Magnetic cores used with planar devices have a different shape than conventional cores used with helical windings.
  • devices built with optimized planar magnetic cores usually exhibit : Significantly reduced height (low profile);
  • Winding structure facilitates interleaving
  • PCB planar
  • the present invention relates to an induction heating device, comprising: a) an open planar magnetic core having at least one center leg! and b) one or more layers of flat coils that are part of a printed circuit board, and which are positioned in a wound-like manner around the center leg of said core, thereby resulting in a low-profile PCB coil.
  • the induction-heating device further comprises a planar transformer.
  • the planar transformer is combined with two or more low-profile PCB coil to realize an induction heating appliance.
  • the open planar magnetic core is having an E-shape or any other core structure.
  • the open planar magnetic core is made of ferrite or any other core material.
  • the open planar magnetic core is having a doubled E-shape for realizing a three-phase coil with a uniform field, by using triple flat coils arrangement.
  • the induction heating device further comprises a control circuitry for controlling the operation of the induction heating appliance.
  • control circuitry includes one or more elements adapted to operate the heating appliance and to provide information to a user during and regarding the operation of said heating appliance.
  • the elements are selected from the group consisting of on/off switch(es), a timer, a display, audible indicators, visual indicators or any combination thereof.
  • Fig. 1 schematically illustrates a high frequency induction heating coil with a single winding, according to an embodiment of the present invention
  • Fig. 2 schematically illustrates an exemplary implementation of a plurality of coils of Fig.1 as an integrated transformer and coils, according to an embodiment of the present invention!
  • Fig. 3 schematically illustrates an implementation of a three-phase coil with a uniform field, according to an embodiment of the present invention.
  • electromagnetic coil or simply a “coil” is used to indicate a conductor that is wound around a core or form to create an inductor or electromagnet, such that when sinusoidal current is passed through the coil a magnetic field is generated.
  • Fig. 1 schematically illustrates a high frequency induction-heating coil 10 with a single winding, according to an embodiment of the present invention.
  • the induction-heating coil 10 comprises a planar magnetic core 1, an optional dielectric insulator 2 and a multilayer Printed Circuit Board (PCB) coil 3.
  • the planar magnetic core 1 is implemented by an open E-shaped magnetic core that is made of ferromagnetic compounds such as ferrites.
  • Winding structure facilitates interleaving.
  • Planar coil enables more turns and more layers in a specific height and width. Since the energy transfer is proportional to the Number of turns Multiplied by the input current flowing throw the coil. Enlarging the number of turns reduces the input current (at a specific power level) and a step down transformer may not be needed.
  • the same circuit with a planar coil, without a step down transformer, will have only approximately 7.5A input current. Not only that less magnetic components are needed, much lower power loses are expected.
  • PCB copper trace unlike copper wire will suffer much power losses at the same rated current due to his flat structure, e.g. 10A current will require a copper trace with a 0.105mm trace thickness (3 oz/ft A 2) and a 2.4mm trace width while skin depth at 100 kHz is 0.24mm.
  • the equivalent copper wire has a 0.566mm diameter and therefore more affected by the skin effect.
  • Fig. 2 shows a device that can be used in conjunction with the invention.
  • the device illustrated in this figure is particularly convenient because it provides an integrated transformer and coils in a low profile form.
  • the device generally indicated by numeral 20 in the figure comprises four induction heating coils 10 (of Fig. l) and a planar transformer that includes an upper E-shaped core 11A, a lower E-shaped core 11B and several layers of primary and secondary windings as indicated by numerals 4, 5, 21 and 22.
  • Fig. 2 Due to system requirements on a specific height and width the winding space is limited.
  • the embodiment shown in Fig. 2 uses a planar transformer to meet the power requirements by enlarging the coil current (& the trace width) and decreasing the number of coil turns or by decreasing the coil current (& the trace width) and enlarging the number of turns.
  • a thorough design will have to integrate the current, trace width, trace thickness and the circuit board withstands to rated voltage (to calculate spacing between traces) for optimum point of electromagnetic flex (proportional to Nxl) at a specific rated power.
  • planar transformer can be based on known techniques, e.g., such as the low-profile planar type transformer disclosed in the European Patent 476, 114 and therefor will not be discussed thoroughly.
  • the layers indicated by numeral 21 are thin dielectric insulators materials (e.g., mylar or polyemide) and the layers indicated by numeral 4 are insulated bobbins. Both layers 21 and 4 are insolating members needs to meet the isolation standards (e.g., creepage length and clearance) of the safety agencies.
  • the layers indicated by numeral 5 are primary windings of the planar transformer.
  • the layers indicated by numeral 22 are secondary windings of the planar transformer. The primary windings 5 and secondary windings 22 connected serially to the windings of the planar coils as indicated by layers 3.
  • Fig. 3 schematically illustrates an implementation of a three-phase coil 30 with a more uniform field, according to an embodiment of the present invention.
  • the three-phase coil comprises a doubled E-core 32 and corresponding triple planar coils 31 that are part of a single printed circuit board.
  • the doubled E-core 32 includes 3 center legs such that each coil of the triple planar coils 31 is positioned in a wound-like manner around each center leg of the doubled E-core 32.
  • the triple planar coil 31 provides three terminals (each terminal from each one of the three coils), such that each terminal represents a single phase as indicated by numeral 33, 34 and 35.
  • the arrangement described in the figures results in a low profile planar (PCB) coil with or without an integrated planar transformer.
  • the resulting coil based product can be manufactured easily inexpensively and most important by mass production with automated procedure.
  • the proposed arrangement uses a low profile PCB with a Ferrite E-core, therefor low losses with low EMI radiation are provided.
  • planar surface area that enables improved heat dissipation capability, greater magnetic cross-section area, enabling fewer turns in the coil, less AC winding resistance (lower coil loses) and a low percent of deviation between the coil's components.
  • the suggested induction heating coil can be combined and implemented as a cooking appliance (not shown) including an outer body that includes a cooktop with four surface heating units which are positioned in spaced apart pairs as realized in many common stoves.
  • Each surface heating unit comprises an induction element, which is configured as one or more of the induction heating coil 10 discussed above.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Induction Heating (AREA)

Abstract

An induction heating device, comprising an open planar magnetic core with at least one center leg and one or more layers of flat coils that are part of a printed circuit board, and which are positioned in a wound-like manner around the center leg of said core, thereby resulting in a low-profile PCB coil. The induction heating device may also include a planar transformer, combined with two or more low-profile PCB coils to realize an induction heating appliance.

Description

AN INDUCTION HEATING DEVICE
Field of the Invention
The present invention relates to the field of induction heating system. More particularly, the invention relates to a high frequency induction heating coils and a method for providing low-profile Printed Circuit Board (PCB) type coil, with or without an integrated planar transformer.
Background of the invention
Induction Heating (IH) concept is familiar for more than a decade and has established itself as a dominate heat treatment technique especially in the metal production, forging, tube welding, melting and other metal processing industries.
The basic electromagnetic phenomenon that induction-heating process relays on is quite simple. By generating an alternating current in an induction coil a time-variable magnetic field will be produced. The magnetic field will have the same frequency as the coil current. The strength of the magnetic field in a specific point is depending on the current flowing in the induction coil, the number of turns, the coil geometry, and the distance from the coil. The time-variable magnetic field will induce eddy currents in the workpiece located near the coil.
Alternating eddy currents produces heat according to Joule effect (ΙΛ2 R) since eddy currents are a direct result of the magnetic flex flowing throw the workpiece the currents in the coil windings needs to be high (or the number of turns) for a fast heating process. Therefor AC-AC converters circuit usually includes a step down AC transformer with a high winding turns ratio in order to produce the required high currents. In most cases due to system demands of specific height and width a usage of high number of turns cannot be performed. Another important phenomenon usually called "skin effect" describes the non-uniform current through a conductor when an alternating power source is applied. The current density will decrease from the surface of the conductor towards its center. The layer that the current flows through is called Reference depth or Penetration depth. Reference depth depends on the frequency and material properties as described in Equation (l):
Figure imgf000003_0001
where
p - electric resistivity [Ω-cm]
μ - permeability of the air
/- frequency [Hz]
Reference depth plays a fundamental role in induction heating theory. The reference depth needed depends on the IH application and can be classified to low, up to 3 kHz! medium, from 3 to 20 kHz! high, from 20 to 100 kHz! and RF, above 100 kHz. The present invention can be applied in all of those areas.
Several more electromagnetic phenomena, such as proximity effect, ring effect, and end and edge effects plays an important role in understanding the induction heating phenomena but for sake of clarity would not be discussed in this description.
Most IH appliances combine three fundamental parts : high frequency generator (AC-AC converter), high frequency transformer (to enlarge the output currents) and an induction heating coil.
- Domestic heating appliances usually use a planar helical coil made of copper wire or high cost copper Litz wire with a shielding Aluminum plate to reduce the EMI radiation.
- High power industrial appliances usually use a hollow conductor with water cooling systems.
Helical windings of conventional magnetic devices have some major disadvantages: • A relatively large profile and therefore only small number of turns can be used, e.g. a domestic planar helical coil made with copper Litz wire for a 3 Kw load can be made of a 16mm2 Litz wire with an outer radius 10 cm (inner radios is 0, with a total of 13 turns), a 20 Kw Industrial IH appliance a can use a 5 turns helical coil made of hollow copper conductor with a total height of 10 cm, outer radius of 20 cm and an inner radius of 16 cm.
• High conduction losses due to "skin effect" phenomenon.
- Domestic IH appliances use Litz wire in order to decrease those losses (expensive solution).
- Industrial IH appliances e.g. a 25 KVA induction-heating appliance will have about 40A input current and up to 1200A output current. Therefor uses a hollow conductors with water cooling circulation in order to decrease the heat generates in the conductor due to high amplitude high frequency currents (and due to the heat radiation from the work piece). This solution is expensive, requires a relatively large space (needs a cooling tank) and does not solve the power losses problem.
• High leakage inductance due to the absence of an electromagnetic core (Air coil).
• Usually a high percent of deviation between the components.
Although IH is not new in the industrial market it has not yet fully spread in the industrial market as a heat treatment method due to large initial costs.
The present invention proposes a modified planar magnetic system. In contrast to the helical wire windings of conventional magnetic devices, the windings of planar transformers and inductors are located on flat surfaces (PCB— Printed Circuit Board) extending outward from the core center leg. Magnetic cores used with planar devices have a different shape than conventional cores used with helical windings. Compared to a conventional magnetic core of equal core volume, devices built with optimized planar magnetic cores usually exhibit : Significantly reduced height (low profile);
Greater surface area, resulting in improved heat dissipation capability!
Greater magnetic cross-section area, enabling fewer turns!
Smaller winding area!
Winding structure facilitates interleaving!
Lower leakage inductance resulting from fewer turns and interleaved windings! Less AC winding resistance! and
Excellent reproducibility, enabled by winding structure.
It is an object of the present invention to provide a low profile planar (PCB) coil with or without an integrated planar transformer that utilizes the aforementioned advantages of the magnetic cores that are used with planar devices, such that the resulting product can be manufactured easily inexpensively and most important by mass production with automated procedure.
It is another object of the present invention to provide coils which have low power losses, low leakage inductance with low EMI.
It is yet another object of the present invention to provide coils which have a compact structure, yet with low output currents and low conduction losses.
Other objects and advantages of the invention will become apparent as the description proceeds.
Summary of the Invention
The present invention relates to an induction heating device, comprising: a) an open planar magnetic core having at least one center leg! and b) one or more layers of flat coils that are part of a printed circuit board, and which are positioned in a wound-like manner around the center leg of said core, thereby resulting in a low-profile PCB coil. According to an embodiment of the present invention, the induction-heating device further comprises a planar transformer.
According to an embodiment of the present invention, the planar transformer is combined with two or more low-profile PCB coil to realize an induction heating appliance.
According to an embodiment of the present invention, the open planar magnetic core is having an E-shape or any other core structure.
According to an embodiment of the present invention, the open planar magnetic core is made of ferrite or any other core material.
According to an embodiment of the present invention, the open planar magnetic core is having a doubled E-shape for realizing a three-phase coil with a uniform field, by using triple flat coils arrangement.
According to an embodiment of the present invention, the induction heating device further comprises a control circuitry for controlling the operation of the induction heating appliance.
According to an embodiment of the present invention, the control circuitry includes one or more elements adapted to operate the heating appliance and to provide information to a user during and regarding the operation of said heating appliance. For example, the elements are selected from the group consisting of on/off switch(es), a timer, a display, audible indicators, visual indicators or any combination thereof.
Brief Description of the Drawings
In the drawings: Fig. 1 schematically illustrates a high frequency induction heating coil with a single winding, according to an embodiment of the present invention!
Fig. 2 schematically illustrates an exemplary implementation of a plurality of coils of Fig.1 as an integrated transformer and coils, according to an embodiment of the present invention! and
Fig. 3 schematically illustrates an implementation of a three-phase coil with a uniform field, according to an embodiment of the present invention.
Detailed Description of the Invention
Throughout this description the term "electromagnetic coil" or simply a "coil" is used to indicate a conductor that is wound around a core or form to create an inductor or electromagnet, such that when sinusoidal current is passed through the coil a magnetic field is generated.
Reference will now be made to several embodiments of the present invention, examples of which are illustrated in the accompanying figures. Wherever practicable similar or like reference numbers may be used in the figures and may indicate similar or like functionality. The figures depict embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein.
Fig. 1 schematically illustrates a high frequency induction-heating coil 10 with a single winding, according to an embodiment of the present invention. The induction-heating coil 10 comprises a planar magnetic core 1, an optional dielectric insulator 2 and a multilayer Printed Circuit Board (PCB) coil 3. In this embodiment, the planar magnetic core 1 is implemented by an open E-shaped magnetic core that is made of ferromagnetic compounds such as ferrites.
The major advantages of a PCB coil with an open E-shaped core over a conventional Air (wire wound) coil are summarized as follows :
• Fewer turns enables due to greater magnetic cross-section area.
• Fewer turns and interleaved windings enables due to Lower leakage inductance.
• Winding structure facilitates interleaving.
• Planar coil enables more turns and more layers in a specific height and width. Since the energy transfer is proportional to the Number of turns Multiplied by the input current flowing throw the coil. Enlarging the number of turns reduces the input current (at a specific power level) and a step down transformer may not be needed. For example, A single phase IH coil at rated power of 3 Kw (Vin=400vDC) with a helical Litz wire windings using a 10: 1 step down transformer will have approximately 75A input current. The same circuit with a planar coil, without a step down transformer, will have only approximately 7.5A input current. Not only that less magnetic components are needed, much lower power loses are expected.
• PCB copper trace unlike copper wire will suffer much power losses at the same rated current due to his flat structure, e.g. 10A current will require a copper trace with a 0.105mm trace thickness (3 oz/ftA2) and a 2.4mm trace width while skin depth at 100 kHz is 0.24mm. The equivalent copper wire has a 0.566mm diameter and therefore more affected by the skin effect.
• Significantly reduced height (low profile);
• Greater surface area, resulting in improved heat dissipation capability!
• Smaller winding area!
• Less AC winding resistance!
• Winding structure enables excellent reproducibility. All the above will be better understood through the following illustrative and non- limitative examples of IH applications.
Fig. 2 shows a device that can be used in conjunction with the invention. The device illustrated in this figure is particularly convenient because it provides an integrated transformer and coils in a low profile form. The device generally indicated by numeral 20 in the figure comprises four induction heating coils 10 (of Fig. l) and a planar transformer that includes an upper E-shaped core 11A, a lower E-shaped core 11B and several layers of primary and secondary windings as indicated by numerals 4, 5, 21 and 22.
Due to system requirements on a specific height and width the winding space is limited. The embodiment shown in Fig. 2 uses a planar transformer to meet the power requirements by enlarging the coil current (& the trace width) and decreasing the number of coil turns or by decreasing the coil current (& the trace width) and enlarging the number of turns. According to an embodiment of the present invention, a thorough design will have to integrate the current, trace width, trace thickness and the circuit board withstands to rated voltage (to calculate spacing between traces) for optimum point of electromagnetic flex (proportional to Nxl) at a specific rated power.
The design of the planar transformer can be based on known techniques, e.g., such as the low-profile planar type transformer disclosed in the European Patent 476, 114 and therefor will not be discussed thoroughly.
With respect to Fig. 2, the layers indicated by numeral 21 are thin dielectric insulators materials (e.g., mylar or polyemide) and the layers indicated by numeral 4 are insulated bobbins. Both layers 21 and 4 are insolating members needs to meet the isolation standards (e.g., creepage length and clearance) of the safety agencies. The layers indicated by numeral 5 are primary windings of the planar transformer. The layers indicated by numeral 22 are secondary windings of the planar transformer. The primary windings 5 and secondary windings 22 connected serially to the windings of the planar coils as indicated by layers 3.
Fig. 3 schematically illustrates an implementation of a three-phase coil 30 with a more uniform field, according to an embodiment of the present invention. The three-phase coil comprises a doubled E-core 32 and corresponding triple planar coils 31 that are part of a single printed circuit board. The doubled E-core 32 includes 3 center legs such that each coil of the triple planar coils 31 is positioned in a wound-like manner around each center leg of the doubled E-core 32. The triple planar coil 31 provides three terminals (each terminal from each one of the three coils), such that each terminal represents a single phase as indicated by numeral 33, 34 and 35.
As will be appreciated by the skilled person the arrangement described in the figures results in a low profile planar (PCB) coil with or without an integrated planar transformer. The resulting coil based product can be manufactured easily inexpensively and most important by mass production with automated procedure. Moreover, unlike the helical windings of conventional magnetic devices, the proposed arrangement uses a low profile PCB with a Ferrite E-core, therefor low losses with low EMI radiation are provided.
Additional advantages provided by the invention is the planar surface area that enables improved heat dissipation capability, greater magnetic cross-section area, enabling fewer turns in the coil, less AC winding resistance (lower coil loses) and a low percent of deviation between the coil's components.
For example, the suggested induction heating coil can be combined and implemented as a cooking appliance (not shown) including an outer body that includes a cooktop with four surface heating units which are positioned in spaced apart pairs as realized in many common stoves. Each surface heating unit comprises an induction element, which is configured as one or more of the induction heating coil 10 discussed above.
All the above description and examples have been given for the purpose of illustration and are not intended to limit the invention in any way. Many different mechanisms, electronic and logical elements can be employed, all without exceeding the scope of the invention. The terms, "for example", "e.g.", "optionally", as used herein, are intended to be used to introduce non-limiting examples. While certain references are made to certain example system components, other components can be used as well and/or the example components can be combined into fewer components and/or divided into further components.

Claims

1. An induction heating device, comprising:
a. an open planar magnetic core having at least one center leg! and b. one or more layers of flat coils that are part of a printed circuit board, and which are positioned in a wound-like manner around the center leg of said core, thereby resulting in a low-profile PCB coil.
2. An induction heating device according to claim 1, further comprising a planar transformer.
3. An induction heating device according to claim 2, in which the planar transformer is combined with two or more low-profile PCB coils to realize an induction heating appliance.
4. An induction heating device according to claim 1, in which the open planar magnetic core is having an E-shape or any other core structure.
5. An induction heating device according to claim 1, in which the open planar magnetic core is made of ferrite or any other core material.
6. An induction heating device according to claim 1, in which the open planar magnetic core is having a doubled E-shape for realizing a three-phase coil with a uniform field, by using triple flat coils arrangement.
7. An induction heating device according to claim 3, further comprising a control circuitry for controlling the operation of the induction heating appliance.
8. An induction-heating device according to claim 7, in which the control circuitry includes one or more elements adapted to operate the heating appliance and to provide information to a user during and regarding the operation of said heating appliance.
9. An induction-heating device according to claim 8, in which the elements are selected from the group consisting of: on/off switch(es), a timer, a display, audible indicators, visual indicators or any combination thereof.
PCT/IL2015/050086 2014-01-30 2015-01-26 An induction heating device WO2015114623A1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108696957A (en) * 2017-04-07 2018-10-23 佛山市顺德区美的电热电器制造有限公司 Coil panel and its processing method, electromagnetism cooking equipment
WO2022206329A1 (en) * 2021-04-02 2022-10-06 青岛海尔滚筒洗衣机有限公司 Electromagnetic heating module and clothes treatment device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6069548A (en) * 1996-07-10 2000-05-30 Nokia Telecommunications Oy Planar transformer

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6069548A (en) * 1996-07-10 2000-05-30 Nokia Telecommunications Oy Planar transformer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108696957A (en) * 2017-04-07 2018-10-23 佛山市顺德区美的电热电器制造有限公司 Coil panel and its processing method, electromagnetism cooking equipment
WO2022206329A1 (en) * 2021-04-02 2022-10-06 青岛海尔滚筒洗衣机有限公司 Electromagnetic heating module and clothes treatment device

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