JP2018092709A - Magnetic resonance heat generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic resonance heat generator which can supply electromagnetic force of electromagnetic induction heating to a remote location by using magnetic resonance.SOLUTION: An oscillation coil 1 excited by electric power is brought close to a resonance coil 2 forming an LC resonance circuit having the same frequency as that of the oscillation coil. As a result, the oscillation coil and the resonance coil resonate with each other and are magnetically coupled to each other. By forming a heat generator into a coil shape or by using a heating resistor as a load, the heat generator is caused to magnetically resonate with the oscillation coil, thereby supplying heat to a remote location. The low-cost heat generator is formed by using the coil itself as a resistance heat generator so that a temperature of the heat generator may be estimated based on variations in resonance frequency of the oscillation coil that has been magnetically coupled, which is derived from variations in LC resonance frequency of the heat generator due to temperature/electrical characteristics of the heat generator.SELECTED DRAWING: Figure 2

Description

  The present invention performs heating by transmitting electric power by magnetic resonance for heating such as cooking.

Conventionally, IH (electromagnetic induction heating) has been used for heating such as cooking, but heating was not possible unless a specific heating object such as metal was brought into close contact with the electromagnetic induction portion.
(For example, Patent Document 1)

When the pan bottom was not flat, it was necessary to make the electromagnetic induction part into a special shape.
(For example, Patent Document 2)

The device is complicated to transmit electric power by electromagnetic induction.
(For example, Patent Document 3)

There was a means of transmitting power with a simple circuit.
(For example, Patent Document 4)

JP, 2014-136003, A clay pot for IH cooker

JP, 2004-357886, A Induction heating cooking device

JP, 2015-144508, A Wireless power transmission system

JP, 2011-193663, A Magnetic resonance circuit and sensor circuit

  A problem to be solved is a method of heating by transmitting power to a place where electricity is isolated through a container such as a pot.

  The present invention transmits power in an oscillating circuit having a resonance condition and a resonant circuit by a magnetic resonance phenomenon, and the power generated in the resonant circuit is heated by the circuit itself or by secondary induction heating from the resonant circuit. The content heating element is heated without being directly heated.

An alternating current is passed from the oscillation circuit 9 to the oscillation coil 1 in the vicinity of the resonance coil 2, and the same frequency as the LC resonance frequency formed by the resonance coil 2 and the resonance capacitor 6 is applied to the oscillation coil 1.

When the resonance coil 2 and the oscillation coil 1 resonate at the same frequency, even if the distance between the coils increases, the magnetic coupling state is maintained and the magnetic transmission can be performed efficiently.

In addition, the magnetic resonance phenomenon is not a pair of resonance coil 2 and oscillation coil 1, but if the resonance frequency is the same, the resonance coil 2 operates in cooperation with each other, and another resonance coil is generated by the magnetic field of resonance coil 2. 2, it is possible to provide a plurality of resonance coils 2 for one oscillation coil 1, and conversely, it is possible to concentrate power in one resonance coil 2 for a plurality of oscillation coils 1. .

Since there is a prior art for power transmission based on this magnetic resonance, the details thereof will be omitted here, but the transmission distance can be transmitted over a long distance which is not a ratio of the heating range of induction heating such as an IH heater.

Utilizing this characteristic, non-contact power transmission is performed between the oscillation coil 1 and the resonance coil 2, and the object to be heated is directly heated using the resonance coil 2 itself as a heating element.

As a heat generation method, the current generated in the resonance coil 2 can be supplied by supplying power to a heating resistor such as a separate nichrome wire. However, if the resonance coil 2 itself is configured as a resistor, a separate heating element can be used. It becomes unnecessary.

In addition, a magnetic core is not essential for the resonance coil 2, but when a core is provided for inductance adjustment and magnetic leakage countermeasures, the magnetic core itself becomes the heat generating magnetic core 4 by using a material having a large eddy current loss and magnetic hysteresis loss. It becomes a heating element with good heat transfer efficiency.

Further, the resonance capacitor 2 may be provided separately in the resonance coil 2, but if a material having a large dielectric constant is used as the insulator of the resonance coil 2, an LC resonance circuit is formed by the parasitic dielectric capacitance of the coil itself.

Even if it is simply placed in water as a spiral stainless closed circuit, water functions as a dielectric and the required LC circuit is formed. As long as the coil has a resistance due to the flowing current, all the electric power is converted into heat, so any material can be used as long as it is a conductor.

If a temperature higher than the boiling point is required, insulating the heat-resistant steel with ceramic can cope with a high temperature exceeding 1000 degrees, and the high-temperature exothermic magnetic core 4 can be easily manufactured.

Even at a high temperature, electric power can be transmitted through a thick heat insulating material, so that it is easy to provide a heating structure with high heat retention performance.

Even in vacuum insulation with a high thermal insulation effect, it can be used because it transmits magnetic force, and depending on the resonance frequency, nonmagnetic materials such as aluminum, copper, and austenitic stainless steel can transmit magnetic lines of force, so eddy current heat generation by the conductor can occur. Things that accompany it are available.

In addition, by installing a non-magnetic conductor at a location where the magnetic lines of force 10 are transmitted, it is possible to use the induction heating of the intermediate substance without depending on the heat generation of the resonance coil 2 itself.

Further, since the transmitting coil 1 is basically the same as the IH stove, it can be used as a conventional IH stove, and can function as a normal IH stove when resonance by the resonance coil 2 cannot be detected. It becomes.

The resonance coil 2 is detected by detecting the voltage of the resonance coil 2 only by detecting the voltage because the resonance frequency of the transmission coil 1 at the time of resonance and the power consumed in the resonance coil 2 appear as a resonance voltage drop of the transmission coil 1. It is easy to estimate the state, and when functioning as IH, if the transmitting coil 1 is transmitted at a frequency different from the resonance frequency, the load difference can be estimated.

The LC resonance circuit including the transmission coil 1 and the resonance capacitor 6 including the parasitic capacitance and the heat generating magnetic core 4 changes in capacitance and permeability depending on the temperature, and the resonance frequency exerted on the oscillation coil 1 that is magnetically coupled depending on the temperature of the heating element varies. Will change.

If this characteristic is measured in advance, temperature measurement based on non-contact can be performed from the relationship between the temperature of the heating element and the resonance frequency.

Even when used as an IH heater, the temperature of the heating body can be estimated from the resonance frequency of the transmitting coil 1 if the properties of the induction heating body are known.

It is also possible to add a thermal switching circuit typified by a thermostat to the resonance coil 2 so that the circuit of the resonance coil 2 is opened and the heat generation is controlled to reach a constant temperature in response to a rise in temperature. .

Further, since the resonance coil 2 has an electromotive force, it is possible to connect a load such as a light emitting decoration by an LED or the like, or a stirring by a motor.

The effects will be described for each item below.

The heat insulation in the one heat insulating container can be easily performed by the magnetic resonance heat generation by which the amount of heat is generated remotely by the power transmission means by magnetic resonance.
2 Since the container does not reach a temperature higher than that of the object to be heated, safety is high.
3 Heat loss due to heat quantity and heat dissipation of the container is reduced.
4 Heating in a sealed container becomes possible.

1 structure that uses direct heat source heating to Joule heat generated by a resistor is simple and the heating element manufacturing cost is low.
2 High durability due to simple structure.

Inductive heating in a place away from the 1 oscillation coil 1 can be performed as Joule heat generated in the conductor by magnetic induction caused by magnetic resonance.
2 High degree of freedom in material and shape of heating element.
3 The heated object itself can be directly heated as a heating element.

Non-contact measurement of the temperature of the heating element from the amount of change in resonance frequency.
1 The temperature sensor can be omitted.
2 The internal temperature can be measured directly.
3 High temperature measurement is possible.

  There are the effects as described above, and they are used in an optimum combination depending on the application.

Circuit (Example 1) Planar heating element (Example 2) Flat coil heating type (Example 3) Winding coil heating type (Example 4) Magnetic path heating type (Example 5)

  1 shows one embodiment of the present invention, which is a basic configuration.

  FIG. 1 shows a circuit (Example 1), which will be described.

In FIG. 1, an oscillation circuit in which a current flows from a positive power source to an LC resonant circuit of a transmitting coil 1 and a resonant capacitor 5 from a high side switching element 7 and flows through a low side switching element 8 (Japanese Patent Laid-Open No. 2011-193663). ) To generate an alternating magnetic field from a magnetic circuit composed of the transmitting coil 1 and the soft magnetic core 3.

Separately from this, an LC resonance circuit composed of the resonance coil 2 and the resonance capacitor 6 is formed as a heating element to constitute a magnetic circuit composed of the resonance coil 2 and the heating magnetic core 4.

When L and C in both circuits are set so that the transmitting coil 1 and the resonant coil 2 resonate at the same frequency and the transmitting coil 1 is energized and oscillated, an electromotive force is generated in the resonant coil 2 due to the magnetic force. Both magnetic circuits maintain the magnetic coupling state by resonance.

At this time, the transmitting coil 1 is in a low heat generation state due to the soft magnetic core 3, and the alternating magnetic field contributes to the electromotive force of the resonance coil 2 and generates Joule heat due to the resistance of the resonance coil 2 itself. .

An alternating magnetic field is applied to the heat generating magnetic core 4 by the alternating magnetic field generated by itself and the alternating magnetic field between the transmitting coil 1 and the resonance coil 2, and the heat generating magnetic core 4 is induction-heated by the magnetic hysteresis and eddy current generated inside.

As a result, the amount of heat transferred as magnetic heating power as a heating element is generated by induction heating of the heat generating magnetic core 4 and Joule heat due to the resistance of the resonance coil 2 itself.

When the heating element is heated and the temperature rises, the magnetic permeability of the heat generating magnetic core 4 as L changes, and in addition, the capacitance of the resonance capacitor 6 as C changes and the LC resonance frequency changes.

When the frequency characteristic of the resonance coil 2 changes, the frequency characteristic of the transmission coil 1 magnetically coupled by resonance also changes, and the temperature change of the heating element can be detected as a frequency change of the transmission coil 1 in a non-contact manner.

In addition, the change in the temperature of the heating element becomes the change in the frequency of the transmitting coil 1 because it changes not only in the resonance but also in the conventional electromagnetic induction heating and the temperature change in the permeability of the heating part. Even in the electromagnetic induction heating of the mold, the temperature can be estimated if the electrical characteristics of the heating part are known.

The magnetic circuit on the oscillation side is made up of a material with low loss, and a soft magnetic material such as ferrite is used as the magnetic core. On the heating element side, the resistance heating element such as nichrome is used as the coil material, and the soft magnetic core having a large iron loss is used as the magnetic core. .

The resonance capacitor 6 can be omitted as a component by using a high dielectric constant ceramic or the like for the insulator of the resonance coil 2 and using the parasitic capacitance of the coil itself.

Further, since the magnetic core is not an essential component, it can also be omitted, and it is possible to connect a heating element such as ceramic as a load using a copper wire to the resonance coil 2.

When a heating element whose calorific value changes with temperature, such as ceramic, is used, there is an effect that the calorific value changes depending on the temperature and is kept at a constant temperature.

Further, by inserting a resistor or a circuit contact depending on the temperature in series in the resonance coil 2, it is possible to turn on / off the resonance magnetic coupling to provide a temperature adjustment function.

For the combination of these elements, a shape material or the like is selected according to the application.

In this embodiment, the oscillation circuit is a simple self-excited oscillation circuit (Japanese Patent Laid-Open No. 2011-193663), but any means can be used as long as the magnetic coupling is achieved by resonance.

  FIG. 2 shows a planar heating element (Example 2), which will be described.

The transmitting coil 1 is formed in a planar spiral shape on the upper surface of the soft magnetic core 3, and an alternating magnetic field is generated by the oscillation circuit 9.

The generated alternating magnetic field generates an electromotive force in the resonance coil 2 formed in a planar spiral shape by the magnetic lines of force 10, and the resonance coil 2 and the transmission coil 1 are in a resonance magnetic coupling state. Heat is generated by self-resistance.

Unless the magnetic field lines 10 in the resonance magnetic coupling state are blocked by a ferromagnetic material, a non-magnetic material such as aluminum transmits the magnetic field lines 10 accompanied by heat generation by eddy currents. Selective heating is also possible by placing the body.

The planar arrangement has a feature that the area of the mutual magnetic circuit is increased and the transmission distance and transmission efficiency are high, and the resonance magnetic coupling state is easily maintained even when the magnetic field lines 10 are interrupted.

  FIG. 3 shows a planar coil heating type (Example 3), which will be described.

The transmitter coil 1 is disposed on the upper surface of the housing 11, the pan 12 filled with the object to be heated 13 is placed on the upper surface thereof, the resonance coil 2 is inserted, and the electric power is transmitted through the magnetic field lines 10 that pass through the pan 12. The object 13 is heated from the inside.

If the material of the pan 12 is not ferromagnetic or the like, the pan 12 made of various materials can be used.

When the porcelain pan 12 which is also an insulated container is used as a typical pan dish using water as the object to be heated 13, the resonance coil 2 is simply made of a nichrome wire spiral, and the resonance capacitor 6 functions as a surrounding of the resonance coil 2. Since this water has a high dielectric constant and acts as a parasitic capacitance of the resonance coil 2 itself, a heating element can be constituted only by the spiral of the nichrome wire and can be easily incorporated in the pan 12 itself.

Moreover, if the resistance heating material is spirally printed on the inner surface of the foam heat insulating material using the pan 12 as a container such as a lunch box, it can be used for a disposable container at low cost. Since most foam materials have a high dielectric constant, they act as a parasitic capacitance of the resonance coil 2 itself like water, and a heating element can be configured only by printing a conductive paint.

In addition, when used for a lunch box, etc., it is possible to achieve a resonance magnetic coupling state with a plurality of resonance coils 2 with a single transmission coil 1, and it is possible to heat and heat at the same time in a state where lunch boxes are arranged in multiple stages and multiple rows. In addition, since the heat insulating container also reduces heat radiation, the running and device costs are low, and the lunch box and the like can be easily taken out.

These heating elements can be in various forms such as throw-in type, seal type, and embedded type, and all of them can be provided at a very low price by using inexpensive materials such as aluminum foil instead of what is called an electric circuit device. is there.

  FIG. 4 shows a winding coil heating type (Example 4), which will be described.

An oscillating circuit 9 generates an alternating magnetic field in a coil obtained by winding the transmitting coil 1 in a cylindrical shape on a cylindrical soft magnetic core 3. At this time, if the angles of the mutual magnetic lines of force between the soft magnetic core 3 and the transmitting coil 1 are substantially orthogonal, the magnetic coupling by magnetic resonance is continued, so that a strict mutual positional relationship need not be considered.

An object to be heated, which is a beverage, is prepared by placing a heating element in which a resonance circuit is formed by a coil in which a resonance coil 2 is wound in a cylindrical shape on a cylindrical heat generating magnetic core 4 in a water cup 14 filled with an object to be heated 13. 13 is heated and kept warm.

By adding the temperature sensitive switch 15 to the resonance coil 2 and controlling the heat generation temperature at an appropriate temperature of the beverage, it is easy to always keep the temperature at the time of drinking.

When the temperature of the object to be heated 13 is low, the temperature sensitive switch 15 is turned on to generate an electromotive force in the resonance coil 2 to generate heat, and when the temperature rises, the circuit of the resonance coil 2 is opened to stop the generation of the amount of heat. This makes it possible to easily control the heat generation amount.

Further, temperature control is possible even with a ceramic heater or the like whose resistance value changes depending on the temperature as a heating element.

In the present embodiment, a method of using the resonance coil 2 separately in the cup 14 which is tableware is shown, and it can be used regardless of the type of tableware, and a plurality of resonance coils 2 are used for a plurality of tableware. A plurality of heat insulations are possible, the shape of the resonance coil 2 may be similar to the shape of a grilled stone pan-like stone, and various shapes and elaborate designs and heat generation temperatures can be set.

Since it is easy to add power such as light emitting decoration by LED and stirring of beverage by a motor by electromotive force of the resonance coil 2 to a shape with elaborate design, the shape and function can be added according to the application.

For example, it is possible to use such a method that the transmitter coil 1 is installed in the Gotake and the battery is driven to keep all dishes in the tableware warm. By adopting such a method, it is possible to provide a dish that is always warm even if it takes a long time for serving.

Also, even if the tableware provided in this way maintains the temperature of the contents, the outside temperature of the tableware is low due to the heat insulation of the tableware itself, heat loss is reduced and at the same time it is not hot and safe to pick up. Can also be provided.

  FIG. 5 shows a magnetic path heating type (Example 5), which will be described.

Magnetic field lines 10 are generated between the resonance magnetic circuit in the U-shaped soft magnetic core 3 by the resonance coil 2 and the magnetic generation circuit by the transmission coil 1 connected to the oscillation circuit 9 in the U-shaped soft magnetic core 3. The object to be heated 13 is installed at the position to be heated.

When the transmission coil 1 is excited by the oscillation circuit 9, the resonance coil 2 is resonantly magnetically coupled via the object to be heated 13, and alternating magnetic field lines are concentrated in the gap formed by the U-shaped soft magnetic core 3.

At this time, if the object to be heated 13 is a ferromagnetic conductor, it generates heat due to hysteresis and eddy current, and if it is a non-magnetic conductor, it generates heat due to eddy current.

By concentrating the magnetic lines of force 10 due to magnetic resonance with the soft magnetic core 3, the object to be heated 13 can be locally heated.

If the object to be heated 13 is a ferromagnetic material, the magnetic field lines 10 are concentrated in the inside of the ferromagnetic material and transmitted through a general magnetic induction heating. It can be used as magnetic resonance heating.

  As described above, the embodiments are configured individually and in combination depending on the application.

  The method constituted by the present invention can be applied to various fields in the industrial field, and typical ones are listed below for each usage state.

Use in cooking equipment.
1 It becomes possible to use cooking utensils that do not have a flat surface, which is difficult with IH cookers.
2 Cooking is also possible in clay pots, glass pots, etc., which are nonconductors that cannot be induction heated.
3 Since the heat-insulating pan is heated from the inside, heat loss is small and energy is saved.
4 Heat insulation is possible even in a heat insulator with high heat insulation.
5. The tableware itself can be used as a cooker.

In addition to the conventional induction heating, 1 induction heating possible area is expanded.
2 Selective heating ranges such as partial quenching and partial melting are possible in heat treatment and the like.
3 Induction heating in a sealed heat-insulated container such as a vacuum or a protective atmosphere is possible. 4 Temperature control of the heating part can be performed in a non-contact manner. .

By simultaneously heating a plurality of heating elements, a plurality of disposable containers such as one lunch can be simultaneously heated and kept warm.
2 Heating elements having different heat generation characteristics can be heated simultaneously to arbitrarily set the temperature distribution in the container.

By enabling remote heat generation 1 Weave a heating element in clothing, shoes, socks, etc., and keep warm directly from a distance.
2 It becomes possible to make cordless such as electric blankets.

DESCRIPTION OF SYMBOLS 1 Transmission coil 2 Resonance coil 3 Soft magnetic core 4 Exothermic magnetic core 5 Resonance capacitor 6 Resonance capacitor 7 High side switching element 8 Low side switching element 9 Oscillation circuit 10 Magnetic field line 11 Case 12 Pot 13 Heated object 14 Hot water cup 15 Temperature switch

Claims (4)

In magnetic induction heating, a magnetic resonance heating element that forms an LC resonance circuit in a heating element and generates heat at a location isolated from a power source by means of power transmission by magnetic resonance. 2. The magnetic resonance heating element according to claim 1, wherein the current transmitted to the resonance coil is directly heated by Joule heat generated by the resistor. The magnetic resonance heating element according to claim 1, wherein the induction Joule heat is generated in a conductor by an alternating magnetic field generated by magnetic resonance. A heating temperature estimation method for non-contact measurement of the temperature of the heating element from the amount of change in the resonance frequency of the LC resonance circuit caused by the temperature change of the magnetic permeability and capacitance of the heating element in magnetic induction heating.

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