JP2018170900A - Wireless power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless power supply device which can reduce a leakage magnetic field while securing a visibility of a power reception device.SOLUTION: In the present invention, a transparent division plate is disposed around a transmission device and a position of the division plate and a power transmission coil is made optimum so that a magnetic flux outputted from the power transmission coil may be intersected with a power reception coil more. Thus, even when a wireless power supply is applied to one which essentially aims to be shown to a person such as an exhibit and a show window, further to one which aims to attract a person, a leakage magnetic field can be reduced while a visibility of a power reception device is secured.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a wireless power feeding apparatus that performs non-contact (wireless) power transmission between a power transmitting apparatus and a power receiving apparatus, and relates to a wireless power feeding apparatus that can move the power receiving apparatus.

  As methods for non-contact power transmission (hereinafter referred to as wireless power feeding), an electromagnetic induction method using electromagnetic induction, a resonance power feeding method via electric field or magnetic field resonance, a microwave power transmission method using radio waves, and the like are known. Among them, the electromagnetic induction method is already commercialized and commonly seen. This method is simple in design and enables high-efficiency wireless power feeding, but has the problem of a short transmission distance. Therefore, a resonance power feeding method that transmits power up to several meters ahead using resonance is proposed, and product development using this technology is being promoted mainly by electrical manufacturers and automobile manufacturers.

  In the resonance power feeding method, power transmission is performed by electromagnetic coupling of a power transmission coil in the power transmission device and a power reception coil of the power reception device. While the coupling coefficient k value between the two coils is small, wireless power feeding is performed by increasing the Q value. However, although the transmission distance can be increased compared to the electromagnetic induction method, the power transmission efficiency is lowered.

  The long transmission distance must be a merit, but there is also a risk. For example, there is an increasing concern about safety such that a person / thing (an object different from the original power receiving object) approaches or further enters between the power transmitting apparatus and the power receiving apparatus. That is, in practical operation, it is necessary to pay attention to electromagnetic exposure to human bodies, precision electronic devices, and the like, and furthermore, countermeasures when metal foreign objects are sandwiched between them are important.

  For example, in the wireless power supply apparatus disclosed in Patent Document 1, the positions of the user and the power supply apparatus are detected and notified, and the operating state of the power supply apparatus is controlled. According to this method, when there is a user (person), the amount of electromagnetic exposure received by the user is reduced by reducing the power supply power.

JP 2014-60822 A

  In Patent Document 1, the amount of power supply is controlled by the positional relationship between the user and the power supply device. However, the apparatus scale becomes large, for example, a separate apparatus for detecting and notifying the positional relationship between the user and the power supply apparatus is required, resulting in an increase in cost.

  In addition, when power is applied to a form that is essentially intended to show people, such as exhibits and show windows, and to attract people, the amount of power supply is reduced when the person approaches. You can't do it.

  In order to solve the above-described problem, a wireless power feeding device according to the present invention includes a power transmission device including a power transmission resonator including a power transmission coil and a resonance capacitor, and a power reception device including a power reception resonator including a power reception coil and a resonance capacitor. And transmitting electric power from the power transmitting device to the power receiving device through an action between the power transmitting coil and the power receiving coil in a contactless manner, and the power receiving device is externally connected through a transparent or translucent partition. Although visible, things other than people and power receiving objects are kept away from the vicinity of the power transmitting device and the power receiving device. The power transmission coil and the power reception coil are arranged so that wireless power transmission can be performed more efficiently, and the power receiving apparatus operates within a certain range of the power transmission apparatus with the proper positional relationship of the partitions.

  Here, the visibility from the outside to the inside is the most important issue, especially when considering exhibits and show windows. For this reason, the partition should be made of glass or plastic with as high a transparency as possible, and the display space and show window for the exhibition should be as large as possible. However, as a result of verification by the inventors, the above-mentioned glass or plastic, which is a dielectric, has an unnecessary leakage magnetic field generated by wireless power feeding (that is, it leaks outside the exhibition or outside the show window and affects other people and things) It was found that the magnetic field that exerts a high degree of electrical conductivity was reduced when a metal thin film having a relatively high conductivity was formed by sputtering or the like. However, if a metal film is formed and the thickness is increased until it reduces unnecessary leakage magnetic field, the transparency important for the visibility is lowered and the original purpose cannot be sufficiently achieved.

  In addition, in order to increase the exhibition space and the show window so as to widen the space where the power can be supplied by wireless power supply, it is necessary to increase the power supplied to the wireless power supply. According to the inventor's verification, if wireless power feeding is performed in a wide space as described above, the leakage magnetic field to the outside of the exhibition space and the show window is further increased, and the wireless power feeding performance itself is performed with sufficient efficiency. Turned out to be difficult.

  Therefore, the inventors have repeatedly conducted electromagnetic field simulation and trial production, and have continued to verify the wireless power feeding performance and the leakage magnetic field. As a result, the magnetic field distribution generated from the coil in the power transmission device and the coil in the power reception device can be received. It was found that there was a technical problem in the magnetic field direction. In order to solve this technical problem, the inventors made a power transmission coil in a spiral shape and housed it in a metal casing forming a power transmission device, and made a power reception coil in a spiral or solenoid shape and placed it in the power reception device. Moreover, a partition made of glass or plastic as transparent as possible was prepared, and arranged at positions corresponding to the inner diameter and outer diameter of the spiral power transmission coil with respect to the inner and outer sides of the partition. Accordingly, the position where the power receiving device is arranged or the movable range is limited by the inner partition, and the region where people and things are brought closer by the outer partition is limited to a safe region.

  Here, when the power receiving apparatus is a moving body, the movement is restricted by the partition when there is a partition as described above, but the time zone (stay time) for moving along the partition is further increased. That is, if the wireless power feeding performance is improved from the vicinity in the vicinity of the partition, power can be supplied to the power receiving apparatus more efficiently. In particular, if the coil in the power receiving device and the coil in the power transmitting device are generally opposed to each other, the magnetic flux from the power transmitting coil is more efficiently intermingled with the power receiving coil.

  Note that the above configuration is not limited to the case where there is one power transmission device and one power reception device. For example, a plurality of power reception devices and power transmission devices can be arranged, or two power transmission devices can be prepared, and one or a plurality of power reception devices can be arranged therebetween. Further, instead of preparing two power transmission devices, the same effect as the above configuration can be obtained by arranging the power reception device between the power reception devices with a magnetic shield device.

  The partition plate can be arranged so as to maintain a relative relationship with the coil as described above by processing and assembling a transparent plate material or cylindrical material. For example, two or more partition plates having different sizes can be provided. It is also possible to put various decorative items for display between them.

  By performing the above configuration, both the visibility of the exhibition and the prevention of people and objects from leaking and approaching the vicinity of a large magnetic field, as well as the ability to sufficiently maintain wireless power supply, can be maintained. It is possible to provide a wireless power feeding device that is highly visible and safe.

It is a figure which shows the outline | summary of the power transmission apparatus (mode 1) of the wireless power feeder of this invention. It is a figure which shows the outline | summary of the power transmission apparatus (mode 2) of the wireless power feeder of this invention. It is a figure which shows the simulation result regarding the direction of the magnetic field generated from the power transmission apparatus (mode 1) of the wireless power feeding apparatus of the present invention. It is a figure which shows the simulation result regarding the direction of the magnetic field generated from the power transmission apparatus (mode 2) of the wireless power feeding apparatus of the present invention. It is a figure which shows the simulation result regarding the magnitude | size of the magnetic field generated from the power transmission apparatus (mode 1) of the wireless power feeder of this invention. It is a figure which shows the simulation result regarding the magnitude | size of the magnetic field generated from the power transmission apparatus (mode 2) of the wireless power feeder of this invention. It is the figure which showed the example of the partition which restrict | limits arrangement | positioning and movement of a receiving device. It is the figure which showed the example which provided the double partition of this invention especially among the partitions which restrict | limit the arrangement | positioning and movement of a receiving device. It is the figure which showed the example which mounted two power transmission apparatuses through the partition among the wireless power supply apparatuses of this invention. It is the figure which showed the example which applied this invention to the fish type robot.

  A wireless power feeding device of the present invention includes a power transmission device having a power transmission resonator configured by a power transmission coil and a resonance capacitor, and a power reception device having a power reception resonator configured by a power reception coil and a resonance capacitor, and the power transmission coil and the power reception Electric power is transmitted from the power transmitting device to the power receiving device in a non-contact manner by the electromagnetic action between the coils.

  In the power receiving device disposed above the power transmitting device, the space in which the power receiving device is disposed is partitioned by a transparent material so that the position is limited to a certain region. Accordingly, the power receiving device can be confined in a position where wireless power feeding is possible, and the visibility of the power receiving device from the outside can be increased. On the other hand, people and things are prevented from approaching a certain area near the power transmission device so as not to receive a leakage magnetic field that exceeds legal regulations and guidelines.

Here, the partition restricts the position where the power receiving device is arranged or the movable region so that the magnetic field generated from the power transmitting coil crosses the power receiving coil more efficiently. Specifically, when the inner diameter of the power transmission coil is Rin and the outer diameter is Rout, the partition is arranged on the inner side of the position of Rin + (Rout−Rin) / 3 from the center of the coil. However, since the power receiving coil is built in the power receiving device, it is more preferable to consider the positional relationship between the power receiving coil and the power receiving device, and further, the wireless power supply target in which the power receiving device is inserted. That is, when the distance between the outer diameter of the power receiving coil and the outermost part of the power receiving device or the outermost part of the wireless power supply object is L, the position of the threshold is Rin + (Rout−Rin) / 3 + L from the center of the coil. In addition, when the power receiving device is a moving body, the inside of the partition can be freely moved, but when moving inside the partition, the time zone for staying near the partition position is relatively increased. For this reason, it is possible to supply power to the power receiving apparatus more efficiently by increasing the wireless power feeding performance in the vicinity of the partition position.
<Example>
Hereinafter, a more detailed embodiment of the present invention will be described with reference to the drawings with specific examples.

  FIG. 1 is a diagram illustrating an outline of a power transmission device of a wireless power feeding device. It consists of a coil 100, a ferrite plate 101, and a metal casing 102 that are formed in a plane spiral shape with litz wires. Although the input / output unit 103 is outside the metal casing for convenience of simulation described later, a power transmission circuit, a resonance capacitor for a power transmission coil, and the like can be arranged inside the metal casing. In this embodiment, a 20-turn coil and an MnZn ferrite plate set the inductance to 400 to 500 μH, and the capacitor capacity for resonating with this is determined to be the resonance frequency, that is, the power transmission frequency selected in this embodiment. Thus, the frequency was adjusted to 85 kHz (hereinafter referred to as the power transmission device of aspect 1).

  FIG. 2 shows a case where two power transmission devices manufactured in the same manner are connected. Since the inductance component is approximately doubled, the resonance capacitor capacity is selected in accordance with this, and is set to the resonance frequency, that is, 85 kHz which is the power transmission frequency (hereinafter referred to as the power transmission device of the mode 2).

  Hereinafter, in order to explain the contents of the present invention, the description of FIGS. 3 to 6 will be made with respect to the magnetic field output from the coils of the above-described modes 1 and 2, which are the main components.

  FIG. 3 is a diagram illustrating a simulation result regarding the direction of the magnetic field output from the power transmission device according to the first aspect. Although the magnetic field from the power transmission device is an AC magnetic field of 85 kHz, the direction of the arrow in the figure indicates the direction of the magnetic field at a certain time. In addition, here, for convenience of explanation, the result of the cross section of the power transmission device shown in FIG. 1 is shown. If attention is paid to the state near the litz wire bundle forming the coil, a magnetic field is generated toward the sky on the inner end face of the litz wire bundle, and the direction turns relatively near the litz wire to form the coil. In the sky above the center of the bundle of lines, it is almost sideways. Further, the outer end face of the litz wire bundle forming the coil circulates downward. On the other hand, as a whole power transmission device, the direction of the magnetic field is relatively uniform toward the sky near the center. It has been found that the position threshold corresponds to a position of Rin + (Rout−Rin) / 3 from the center of the coil when the inner diameter of the power transmission coil is Rin and the outer diameter is Rout. However, since the power receiving coil is built in the power receiving device, it is more preferable to consider the positional relationship between the power receiving coil and the power receiving device, and further, the wireless power supply target in which the power receiving device is inserted. That is, when the distance between the outer diameter of the power receiving coil and the outermost power receiving device or the outermost power supply target is L, the position of the threshold is Rin + (Rout−Rin) / 3 + L from the center of the coil.

  From the above results, it is possible to improve the efficiency of wireless power feeding by arranging the power receiving coil near the inner side of the end face of the litz wire bundle forming the power transmitting coil, and further facing the power receiving coil and facing the power receiving coil. It turns out that it can do well. Conversely, if the power receiving coil is placed directly above the center of the litz wire bundle forming the power transmitting coil, the magnetic field from the power transmitting coil cannot interlace the power receiving coil, so the efficiency of wireless power feeding is very poor. I found out that For this reason, it has been found that it is necessary to limit the position where the power receiving device is arranged or moved as described above when the power receiving device can be wirelessly fed with a degree of freedom of arrangement or when the power receiving device needs to move. .

  FIG. 4 is a diagram illustrating a simulation result regarding the direction of the magnetic field output from the power transmission coil according to the second aspect. Here, for convenience of explanation, the result in the cross section of the power transmission device shown in FIG. 2 is shown. The state and arrangement of the litz wire in the vicinity of the bundle of litz wires forming the coil are as described above. Characteristic in the case of the present embodiment 2 is the magnetic field direction in the vicinity of the center of both power transmission coils and in the sky above, and in comparison with the case of the first embodiment, a magnetic field is generated up to the sky more perpendicular to the coil surface. I understood that. That is, it was found that the power transmission coil of aspect 2 is more suitable for transmitting wireless power feeding power to the power receiving coil.

  FIG. 5 is a diagram showing a simulation result regarding the magnitude of the magnetic field output from the coil according to the first aspect. Here, the current flowing through the coil was 0.5 A. The numbers shown in the figure are numbers indicating the magnitude of the magnetic field in microtesla (μT), and the range is indicated by contour lines. From the figure, it became clear that the closer to the bundle of litz wires forming the coil, the larger the magnetic field was generated.

  The number shown here as 27 (μT) is a guideline value stipulated by the International Commission on Non-Ionizing Radiation (ICNIRP), and in general, guidelines are given to prevent the human body from receiving a magnetic field with a value larger than this. . That is, it is necessary to suppress the magnetic field (exposure of the magnetic field to the human body) applied to the human body to be low by preventing the human body from entering the region indicated by 27 by some method. At the same time, when something other than the original power receiving target (for example, a metal such as a nail) is present in the vicinity of the power transmission device, it must be prevented from being overheated by the magnetic field leaking from the power transmission coil.

  FIG. 6 shows the result of a similar simulation regarding the magnitude of the magnetic field output from the coil according to the second aspect. Here, the current flowing in the coil was similarly set to 0.5A. By arranging two power transmission devices facing each other as shown in FIG. 6, it is possible to prevent a human body from entering between them due to their own structure. From the figure, it is the same as in the case of the coil of aspect 1 that a magnetic field is generated so as to be closer to the bundle of litz wires forming the coil, but further, a magnetic field generated outside between the power transmission devices (hereinafter unnecessary leakage). It was found that a region where a relatively strong magnetic field is generated can be effectively created between the power transmission devices without increasing the magnetic field). Instead of preparing two power transmission devices, one of the power transmission devices can be a magnetic shield. The magnetic shield is configured by, for example, arranging a highly conductive metal such as aluminum or copper, or arranging a material having high magnetic permeability such as a ferrite plate. If a device that limits the unnecessary leakage magnetic field as described above can be arranged on the power transmission device, it is possible to bring about an effect that metal other than a person or a power reception target does not approach the power transmission device.

  FIG. 7 is a partition arranged in order to consider the exposure of the magnetic field to the human body by the unnecessary leakage magnetic field and the wireless power feeding performance, and to maintain visibility from the outside. If the box-shaped partition is made of glass or a transparent plastic material as shown in the figure, and placed above the power transmission device, the above two problems can be solved. That is, since the visibility from the outside is high and the power receiving device is actually receiving wireless power feeding can be visually confirmed, this is particularly useful when the power receiving device is an exhibition mannequin or robot, for example. However, as described in the description of FIG. 3 and FIG. 4, when the power receiving coil of the power receiving device is disposed or moved near the center of the bundle of litz wires forming the power transmitting coil, The problem is that wireless power feeding performance deteriorates at a stretch.

  FIG. 8 shows a configuration in which a partition is provided in addition to the structure shown in FIG. 7 in consideration of the direction of the magnetic field from the power transmission device in order to solve the above problem. That is, the power receiving device is arranged inside the partition by the inner partition so that it can move. Thus, it is possible to efficiently perform wireless power feeding without having to worry about the direction of the magnetic field generated from the power transmission coil. In addition, the outer partition prevents the metal other than the human body and the power receiving object from being exposed to a certain magnetic field. Since the partition can be made of a transparent material, the state of the power receiving device can be visually recognized from outside the partition.

  FIG. 9 shows a wireless power feeding apparatus assembled by combining the above-described methods. That is, two power transmission devices are prepared, and a transparent partition having a double partition between them (in this example, a box whose overall width is larger than that of the power transmission device based on the simulation result) is appropriately set as described above. Arranged. The power receiving device can be freely arranged inside the partition and can be moved. Here, in order to verify the effect of the present invention, the apparatus of the present invention was manufactured and the alternating magnetic field was measured, and it was found that the surrounding leakage magnetic field could be 27 μT.

  As a result, it is possible to reduce the influence of unnecessary leakage magnetic fields without degrading the wireless power feeding performance. I can do it now.

  Here, in general, when the magnetic field resonance method is used, the power transmission distance becomes long. However, according to the study by the inventors, the power transmission distance is extended even by the magnetic field resonance method, particularly when the size of the receiving coil is small. Is known to be difficult. Therefore, it is assumed that power transmission is mainly performed by a magnetic field, and as a result of considering the relationship between the output magnetic field from the power transmission coil and the power receiving coil that receives the magnetic field, the power transmission coil is wound relatively densely around the outer periphery of the coil in a planar spiral shape. More preferably, the power receiving coil was preferably formed in a solenoid shape. Further, it is preferable that the power transmission coil and the power reception coil face each other as much as possible, and the power reception device or the power reception target object including the power reception coil is arranged in the vicinity of the partition or stays in the vicinity of the partition is relatively long. If effective.

  In the main application of the present invention, the power receiving apparatus is installed in a mannequin or a robot displayed on a show window. FIG. 10 shows a case where, for example, a fish-shaped robot is used as an exhibit. The fish-shaped robot has a power receiving device including a solenoid-shaped power receiving coil incorporated therein, and is operated wirelessly by receiving power from the power transmitting device including the spiral power transmitting coil. The partition fills the interior with water, and the fish-type robot moves around in it, but by keeping the weight balance of the power receiving device properly, it can be moved around in the water tank so that the power transmitting coil and the power receiving coil always face each other. it can. Even if the fish robot moves randomly, the time spent at a position where the magnetic field from the power transmission coil near the partition is particularly strongly received can be made relatively longer than the others.

  Therefore, as described above, even when the fish-type robot is small and the power receiving coil is small, the water tank can be moved by receiving sufficient electric power.

  The wireless power feeding apparatus of the present invention can suppress an effective unnecessary leakage magnetic field to the minimum without degrading the wireless power feeding performance. For this reason, it can be effectively used in the case where wireless power supply is applied to a form for attracting people, such as an exhibition or a show window.

DESCRIPTION OF SYMBOLS 100 Power transmission coil 101 Ferrite plate 102 Case 103 Input / output 104 of a power transmission coil Power transmission coil connection line 200 Power transmission device 201 Power reception device 202 Partition

Claims (7)

A power transmission device having a power transmission resonator composed of a power transmission coil and a resonant capacitor;
A power receiving device having a power receiving resonator composed of a power receiving coil and a resonant capacitor;
A wireless power feeder that transmits electric power in a non-contact manner from the power transmission device to the power reception device via an electrical or magnetic action between the power transmission coil and the power reception coil,
It has a power receiving area surrounded by a transparent partition,
The power receiving device is disposed within the power receiving region, the power transmitting device is disposed outside the power receiving region,
The wireless power feeding apparatus, wherein the power receiving apparatus is movable in the power receiving area.   The said transparent partition is comprised by the inner side partition and the outer side partition surrounding the said inner side partition, The said power receiving area | region is an area | region enclosed by the said inner side partition, The Claim 1 characterized by the above-mentioned. Wireless power feeder.   The inner partition is arranged inside the position of Rin + (Rout-Rin) / 3 from the center of gravity of the power transmission coil, where the inner diameter of the power transmission coil is Rin and the outer diameter is Rout. The wireless power feeding apparatus according to 2.   When the distance between the outer diameter of the power receiving coil and the outermost part of the power receiving device or the outermost part of the object to be wirelessly fed is L, the inner partition is arranged inside Rin + (Rout−Rin) / 3 + L. The wireless power feeder according to claim 2,   5. The wireless power feeding apparatus according to claim 1, wherein the power transmission device is disposed on both ends of the power receiving region via the transparent partition. 6.   The power transmission device is disposed on one end face side of the power receiving area via the transparent partition, and a magnetic shield is disposed on the other end face side of the power receiving area via the transparent partition. The wireless power feeder according to claim 1.   The wireless power feeding apparatus according to claim 1, wherein the power receiving coil and the power transmitting coil face each other while maintaining a balance of the power receiving apparatus.

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