Wireless power supply and communication device

Abstract

To provide a wireless power supply and communication device capable of improving transmission efficiency. [Solution] The present disclosure provides a wireless power supply communication device 1 comprising: a first coil 10 having a U-shaped, V-shaped, or U-shaped first yoke 11 arranged opposite to a ferromagnetic plate-shaped member 100 sandwiching it; a second coil 20 having a U-shaped, V-shaped, or U-shaped second yoke 21; a power supply unit for supplying power to the first coil; and a magnetic field application means 30, wherein the two end faces of the first yoke of the first coil and the two end faces of the second yoke of the second coil are arranged opposite to each other sandwiching the plate-shaped member, and the magnetic field application means is capable of applying a magnetic field to the plate-shaped member between the two end faces of at least one of the first yoke and the second yoke.

Description

[Technical Field]

[0001] This disclosure relates to a technology for wireless power transmission and communication via magnetic field coupling through a partition. [Background technology]

[0002] Conventionally, wireless power transfer and communication technologies using electromagnetic waves are known. When the space is air or a vacuum, the loss during the propagation of electromagnetic waves is small, and wireless power transfer and communication are possible. On the other hand, when a partition exists between the transmitter and receiver, the applicability of electromagnetic waves depends on the conductivity and permeability of the materials between the transmitter and receiver, as well as the thickness of the partition. For example, if the partition is made of a conductive material such as aluminum, the electric field of the electromagnetic wave cannot pass through, so wireless power transfer and communication are not possible. Also, ferromagnetic materials such as iron have high permeability, and the magnetic field cannot pass through them, making wireless power transfer and communication using electromagnetic waves difficult.

[0003] A technology is known that enables wireless power transmission and communication using magnetic field coupling and magnetic field resonance of a pair of coils installed on both sides of a partition, rather than electromagnetic waves (see, for example, Non-Patent Document 1). According to Non-Patent Document 1, wireless power transmission and communication using magnetic field coupling can be performed with materials that have high conductivity but low permeability, such as aluminum and non-magnetic stainless steel.

[0004] On the other hand, if the partition is made of a material with high magnetic permeability, such as iron plate, wireless power transmission communication is difficult even when using magnetic field coupling. This is because if the partition has high magnetic permeability, the magnetic flux generated on the transmitting side will pass through the partition and return to the transmitting side, and will not reach the receiving side.

[0005] Patent Document 1 and Non-Patent Document 2 disclose a technology that solves the problem described above, in which wireless power transmission and communication are not possible even with magnetic field coupling when the partition wall is made of iron plate or the like. In this technology, a pair of coils are arranged facing each other across a partition wall, and in particular, the yoke of the coil is made of a material with high magnetic permeability and is U-shaped, and the configuration is presented in which the end faces of the U-shape face each other across the partition wall.

[0006] Patent Document 1 and Non-Patent Document 2 consider the configuration of a pair of coils and a partition wall to be similar to a parallel circuit in an electrical circuit. The magnetic flux generated by the primary coil is divided into a magnetic path passing through the partition wall and a magnetic path passing through the secondary coil. After passing through the partition wall and the secondary coil, the two paths merge again and return to the magnetic path passing through the primary coil. Therefore, by adjusting the balance between the magnetic resistance of the partition wall's magnetic path and the magnetic resistance of the secondary coil's magnetic path, it should be possible to increase the magnetic flux flowing through the secondary coil. A higher magnetic resistance of the partition wall is desirable, so the length of the magnetic path should be long and the cross-sectional area should be small. Therefore, a U-shaped yoke is considered optimal because it separates the ends of the yoke to lengthen the magnetic path, reduce the spread of the magnetic flux, and decrease the cross-sectional area. Furthermore, since it is desirable for the magnetic resistance of the secondary coil's magnetic path to be small, it is recommended to manufacture the yoke from a material with high magnetic permeability, and to avoid the increase in magnetic resistance due to the air gap, the end face of the yoke should be in close contact with the partition wall and positioned so as to be in contact with the end face of the primary coil's yoke. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2024-119695 [Non-patent literature]

[0008] [Non-Patent Document 1] Mai Otsuka et al. IEICE Technical Report, January 2017, Vol. 116, No. 398, pp. 33-38. [Non-Patent Document 2] Yasuyuki Yamamoto et al. Proceedings of the 40th Symposium on Sensors, Micromachines and Applied Systems, October 31, 2023. Paper No. 7P2-PS-63. [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The magnetic resistance of a partition depends on the permeability of the partition material; therefore, to increase magnetic resistance, a lower permeability is preferable. Furthermore, a thinner partition is preferable. However, the partition material and its thickness are often determined by the design of the application, and it is often not possible to change them to conditions favorable for wireless power transfer. Therefore, the improvement in transmission efficiency of the technology described in Patent Document 1 had limitations.

[0010] This disclosure is made in view of these circumstances and provides a wireless power supply communication device capable of improving transmission efficiency. [Means for solving the problem]

[0011] According to one aspect of the present disclosure, a wireless power supply communication device is provided, comprising: a first coil having a U-shaped or V-shaped first yoke arranged opposite to a ferromagnetic plate-shaped member sandwiching it; a second coil having a U-shaped or V-shaped second yoke; a power supply unit for supplying power to the first coil; and a magnetic field application means, wherein the two end faces of the first yoke of the first coil and the two end faces of the second yoke of the second coil are each arranged opposite to the plate-shaped member sandwiching it; and the magnetic field application means is capable of applying a magnetic field to the plate-shaped member between the two end faces of at least one of the first and second yokes.

[0012] According to the above embodiment, a magnetic field from the magnetic field applying means is applied to the plate-shaped member, and a part of the plate-shaped member is magnetized. The magnetized portion reaches a magnetic saturation state, and the differential permeability decreases. As a result, the slope of the minor loop caused by the AC magnetic field applied to the plate-shaped member by the first yoke becomes smaller, and the permeability can be substantially reduced. This increases the magnetic resistance of the plate-shaped member, increases the magnetic flux passing through the second yoke, and provides a wireless power supply communication device with improved transmission efficiency. Furthermore, according to the above embodiment, by modulating the strength of the magnetic field applied by the magnetic field applying means, the permeability of the plate-shaped member can be changed, modulating the transmission efficiency and providing a wireless power supply communication device that can perform communication. [Brief explanation of the drawing]

[0013] [Figure 1] It is an explanatory diagram of the B-H curve and the minor loop of a plate-like member which is a ferromagnetic material in the wireless power feeding communication device of the present disclosure. [Figure 2] It is a diagram showing a typical relationship between the differential permeability and the magnetic field strength when the magnetic field applied to the plate-like member which is a ferromagnetic material is gradually increased. [Figure 3] It is a schematic perspective view of the wireless power feeding communication device according to the first embodiment. [Figure 4] It is a schematic diagram of the magnetic circuit of the wireless power feeding communication device according to the first embodiment. [Figure 5] It is a diagram showing an example in which a permanent magnet is arranged on a plate-like member in the wireless power feeding communication device according to the second embodiment. [Figure 6] It is a schematic cross-sectional view of the wireless power feeding communication device which is a modification of the first embodiment. [Figure 7] It is a schematic cross-sectional view of the wireless power feeding communication device according to the third embodiment. [Figure 8] It is a schematic cross-sectional view of the wireless power feeding communication device according to the fourth embodiment. [Figure 9] It is a schematic cross-sectional view of the wireless power feeding communication device according to the fifth embodiment. [Figure 10] It is a diagram showing the arrangement of the permanent magnet in the example. [Figure 11] It is a diagram (part 1) showing the power transmission efficiency of the example and the comparative example. [Figure 12] It is a diagram (part 2) showing the power transmission efficiency of the example.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present disclosure will be described based on the drawings. In addition, for elements common among a plurality of drawings, the same reference numerals are given, and repeated detailed descriptions of those elements are omitted.

[0015] The wireless power transfer and communication device of this disclosure is characterized by efficiently performing wireless power transfer and communication by applying a magnetic field to the plate-shaped material using a permanent magnet or the like, thereby bringing it to a magnetic saturation state, when performing wireless power transfer and communication with a ferromagnetic plate-shaped member sandwiched between them. A ferromagnetic material is a substance that has the property of being strongly magnetized by an externally applied magnetic field (ferromagnetism). Examples of ferromagnetic materials include iron, nickel, cobalt and alloys containing them (carbon steel, alloy steel, cast iron, etc.) or oxides (ferrite, etc.). Generally, ferromagnetic materials have high relative permeability. Relative permeability is the ratio of the permeability of a material to the permeability of vacuum.

[0016] Figure 1 is an explanatory diagram of the BH curve and minor loop of a ferromagnetic plate-shaped member in the wireless power transmission communication device of this disclosure. Figure 2 is a diagram showing a typical relationship between the differential permeability and the magnetic field strength when the magnetic field applied to the ferromagnetic plate-shaped member is gradually increased. Here, for the sake of explanation, the ferromagnetic plate-shaped member will be referred to as a ferromagnetic material.

[0017] Referring to Figure 1, when an external magnetic field H is applied to a ferromagnetic material, the inside of the ferromagnetic material becomes magnetized, and magnetization M is generated. The magnetic flux density B inside the material is equal to the permeability μ of vacuum in the external magnetic field H. o The product of the two factors and the magnetization M is the sum of the two factors. The relationship between the external magnetic field H and the magnetic flux density B generated inside the material is represented by a loop-shaped graph called the BH curve, as shown in Figure 1. When no external magnetic field H is applied, H=0, the magnetic flux density B is also zero (B=0). However, as the external magnetic field H is gradually increased, the magnetic flux density B increases along the initial magnetization curve shown by the dashed line in Figure 1. As the external magnetic field H increases, the increase in magnetic flux density B becomes gradual, and eventually the magnetization M no longer increases. This state is called magnetic saturation. After reaching magnetic saturation, if the external magnetic field is decreased, the magnetic flux density decreases more gradually than the initial magnetization curve due to hysteresis. After the external magnetic field reaches zero, if an external magnetic field is applied in the opposite direction, the magnetic saturation state is eventually reached. Subsequently, if the external magnetic field is increased again, since only the direction is physically reversed, the magnetic flux density increases along a point-symmetric graph with respect to the origin, and as a result, it draws a loop along the solid line curve in Figure 1.

[0018] When the magnitude of the change in the external magnetic field H does not reach magnetic saturation, the magnetic flux density changes along the curve of the minor loop A shown in Figure 1, for example. The ratio of the change in magnetic flux density to the change in the external magnetic field, i.e., dB / dH, is called the differential permeability. Since permeability is defined as B / H, differential permeability and permeability are strictly different, but since differential permeability is important when an AC magnetic field is applied, in this disclosure, even when referring to differential permeability, it is simply described as permeability. The average of the differential permeability when an AC magnetic field is applied is shown in Figure 1 as μ A This corresponds to the slope of the straight line shown.

[0019] Referring to Figure 2, a typical change in differential permeability is shown when an external magnetic field is applied to a ferromagnetic material and the magnetic flux density is increased along the initial magnetization curve. The differential permeability initially increases with increasing external magnetic field, reaches a peak, and then rapidly decreases as it approaches magnetic saturation. When an external magnetic field is applied to a ferromagnetic material using a permanent magnet or the like, the differential permeability changes similarly depending on the strength of the magnetic field. Therefore, when an AC magnetic field for wireless power transmission via magnetic field coupling is applied while an external magnetic field of a strength that reduces differential permeability is applied using a permanent magnet or the like, minor loop A in Figure 1 shifts to a region with a small differential permeability, as shown in minor loop B, and the effective permeability becomes μ A From μ B This results in a decrease in magnetic resistance. As a result, the magnetoresistance of the ferromagnetic material increases, and the magnetic flux distributed to the secondary coil increases, thereby improving the transmission efficiency of wireless power transfer communication.

[0020] <First Embodiment> Figure 3 is a schematic perspective view of a wireless power transfer communication device according to the first embodiment. Referring to Figure 3, the wireless power transfer communication device 1 according to the first embodiment efficiently transfers power wirelessly by applying a magnetic field to the plate-shaped material 100 with a permanent magnet and causing magnetic saturation when wirelessly transferring power with a ferromagnetic plate-shaped member 100 in between.

[0021] The wireless power supply communication device 1 includes a coil 10, a coil 20, a ferromagnetic plate-shaped member 100, a permanent magnet 30 as a means for applying a magnetic field, and a power supply unit (not shown). The permanent magnet 30 is in contact with the plate-shaped member 100. The plate-shaped member 100 is not limited to the area shown in the schematic diagram; for example, the plate-shaped member 100 may be extended to form a case that covers the coil 20, and the coil 10 may be provided outside the case. When power is supplied from outside to inside the case, the coil 10 is the primary side (power supply side) and the coil 20 is the secondary side (power receiving side). The direction of power supply may be from inside to outside. In that case, the coil 10 is the secondary side and the coil 20 is the primary side. For convenience, the case of power supply from outside to inside (coil 10 is the primary side, coil 20 is the secondary side) will be explained here.

[0022] Coil 10 has a yoke 11 made of a material with high magnetic permeability. Coil 20 has a yoke 21 made of a material with high magnetic permeability. Yokes 11 and 22 are U-shaped. The distance between the ends of the U-shapes is approximately the same, and the shape and area of ​​the ends are also approximately the same. They are arranged to face each other via a plate-shaped member 100. The materials for yokes 11 and 21 are, for example, permalloy (NiFe), electrical steel sheet, and ferrite. Note that yokes 11 and 21 may also be V-shaped or U-shaped.

[0023] In this way, the magnetic flux generated by the primary coil 10 penetrates the plate-shaped member 100 and reaches the secondary coil 20, enabling wireless power transmission. However, some of the magnetic flux generated by the primary coil 10 passes through the plate-shaped member 100 and returns to the primary coil 10 without entering the secondary coil 20. This is magnetic flux leakage that occurs because the plate-shaped member 100 is a ferromagnetic material with low permeability. The main reason why the transmission efficiency of the wireless power transmission communication device 1 via the ferromagnetic plate-shaped member 100 decreases is that the magnetic flux leaks and spreads within the plate-shaped member 100 in this manner.

[0024] Figure 4 is a schematic diagram of the magnetic circuit of the wireless power supply communication device according to the first embodiment. Referring to Figure 4, the situation where the magnetic flux generated by the primary coil 10 flows not only through the secondary coil 20 but also through the plate member 100 can be regarded as equivalent to a magnetic circuit similar to the parallel circuit of the electrical circuit as shown in Figure 4. The configuration of Figure 4 is obtained by rotating the positional relationship of the members in Figure 3 90° to the left. In the magnetic circuit of Figure 4, the state where the magnetic flux circulates through the magnetic path can be analyzed by analogy with the state where the current circulates through the electrical circuit. The index representing the ease of passage of the magnetic flux corresponding to the resistance of the electrical circuit is the magnetic resistance. The magnetic resistance is expressed by the following formula (1). Magnetic resistance = length L / (permeability μ × cross-sectional area S) ··· (1) According to the analysis based on such a magnetic circuit, it can be seen that the magnetic flux generated by the primary coil 10 is divided into the magnetic path passing through the secondary coil 20 and the plate member 100. The state where the magnetic flux is divided is the same as the state where the current is divided in the parallel circuit of the electrical circuit. The ratio in which the magnetic flux is divided between the coil 20 and the plate member 100 is, as in the case of the electrical circuit, the inverse ratio of the magnetic resistance R m2 of the magnetic path of the coil 20 and the magnetic resistance R mFe of the magnetic path of the plate member 100. For example, when (magnetic resistance R m2 of the magnetic path of the coil 20: magnetic resistance R mFe of the magnetic path of the plate member 100 = 1:10), (magnetic flux of the magnetic path of the coil 20: magnetic flux of the magnetic path of the plate member 100 = 10:1).

[0025] From this, if the magnetic flux generated by the coil 10 can reach the coil 20 as much as possible, wireless power supply can be performed efficiently. That is, the magnetic resistance R m2 of the coil 20 should be as small as possible, and the magnetic resistance R mFe of the plate member 100 should be as large as possible.

[0026] The magnetic resistance R m2To reduce this, it is best to increase the cross-sectional area of ​​the yoke 21 and use a material with high magnetic permeability. Since the magnetic permeability can be increased by 100 to 10,000 times by using ferromagnetic materials, material selection is particularly effective. A shorter length for the yoke 21 is preferable, but as will be discussed later, the magnetic resistance of the plate-shaped member 100... mFe To increase the efficiency, the length of the yoke must be increased. However, if a material with high magnetic permeability is used for the yoke 21, the effect of increased magnetic permeability far outweighs the decrease in efficiency caused by the slightly longer yoke.

[0027] Magnetic resistance R of plate-shaped member 100 mFe To increase the magnetic resistance R, the length of the magnetic path of the plate-shaped member 100 should be increased, that is, the distance between the ends of the coil 20's yoke should be longer. Also, to reduce the cross-sectional area of ​​the plate-shaped member 100, its thickness should be thinner. At this time, the magnetic resistance R mFe The area corresponding to the cross-sectional area is the range in which the magnetic flux spreads within the plate-shaped member. Therefore, since a narrower range of magnetic flux spread is desirable, the coil 20 is better shaped like a U or a U.

[0028] Magnetic resistance R of plate-shaped member 100 mFe Another method to increase the magnetic permeability is to reduce the magnetic permeability of the plate-shaped member 100. However, the material of the plate-shaped member 100 is often predetermined by the design of the container or device to which it will be applied, and cannot be changed according to the needs of the wireless power supply communication device 1.

[0029] In this embodiment, by arranging the permanent magnet 30 in contact with the plate-shaped member 100, a magnetic field from the permanent magnet 30 is applied to the plate-shaped member 100, and a portion of the plate-shaped member 100 is magnetized. The magnetized portion reaches a magnetic saturation state, and the differential permeability decreases. As a result, the minor loop caused by the alternating magnetic field applied to the plate-shaped member 100 by the primary-side yoke 11 becomes less steep, as shown in minor loop B in Figure 1, and the permeability can be substantially reduced. This increases the magnetic resistance of the magnetic path of the plate-shaped member 100, increases the magnetic flux passing through the secondary-side yoke 21, and improves the transmission efficiency of the wireless power supply communication device 1.

[0030] The permanent magnet 30 is not particularly limited, but for example, ferrite magnets, SmCo magnets, NeFe magnets, Alnico magnets, etc. can be used.

[0031] In Figure 3, the permanent magnet 30 is in contact with the plate-shaped member 100. This increases the magnetic flux density generated inside the plate-shaped member 100 from the permanent magnet 30, enabling efficient wireless power transfer. However, the permanent magnet 30 may be positioned away from the plate-shaped member 100, as long as the magnetic field from the permanent magnet 30 is applied to the plate-shaped member 100.

[0032] <Second Embodiment> The wireless power supply communication device according to the second embodiment relates to various configurations of permanent magnet arrangement on a plate-shaped member and is a modification of the first embodiment. In the first embodiment, as shown in Figure 3, one permanent magnet 30 is attached by magnetic force to the plate-shaped member 100 between the ends of the U-shaped yoke 11, but the invention is not limited to this, and the arrangement of the permanent magnet 30 may be other than that shown.

[0033] Figure 5 shows an example of arranging a permanent magnet on a plate-shaped member in a wireless power transfer communication device according to the second embodiment. Referring to Figures 5(a) to (c) in conjunction with Figures 3 and 4, the permanent magnet 30 of the wireless power transfer communication device has a magnetic resistance R in the magnetic path passing through the plate-shaped member 100. mFe The magnets are arranged to increase the magnetic flux path (for example, a path inside the plate-shaped member 100 along the main surface of the plate-shaped member 100) and obstruct it. Since the magnetic field is generated from the end face 11a of the yoke 11, it is preferable to arrange the permanent magnets 30 so as to obstruct the path of magnetic flux with high magnetic flux density in the region where the magnetic flux is concentrated around it, and along the line connecting the end faces 11a of the two yokes.

[0034] Figures 5(a) to 5(c) illustrate various configurations of the arrangement of the permanent magnets 30 on the end faces 11a of the U-shaped yoke 11 on the plate-shaped member 100. Referring to Figure 5(a), a group of permanent magnets 31 consisting of multiple permanent magnets 30 is arranged on the median line of the straight line connecting one end face 11a of the U-shaped yoke 11 to the other end face 11a. The region along the straight line connecting one end face 11a of the U-shaped yoke 11 to the other end face 11a is where the magnetic flux is most concentrated. By increasing the magnetic resistance of the magnetic path in this region, that is, by decreasing the permeability, the magnetic flux passing through the secondary yoke 21 can be increased. As a variation of this, the permanent magnet group 31 has the permanent magnets 30 arranged in a straight line, but it is not limited to this, and they may be arranged in a zigzag line or a double line. Also, the permanent magnets 30 may be cylindrical, cubic, or rectangular.

[0035] Referring to Figure 5(b), a group of permanent magnets 32 is arranged, with multiple permanent magnets 30 surrounding each of the two end faces 11a of the U-shaped yoke 11. The group of permanent magnets 32 prevents magnetic flux from leaking out from the end faces 11a of the yoke 11 and spreading throughout the plate-shaped member 100. The arrangement of the permanent magnets 30 in the group of permanent magnets 32 is not limited to a circular shape, but can be arranged in the shape of a closed curve. Closed curves can be, for example, triangles, squares, or star shapes. The group of permanent magnets 32 may also be arranged in the shape of multiple closed curves, enclosing the end faces 11a of the yoke 11 in a double or triple layer. Furthermore, the permanent magnets 30 may be cubic or rectangular, not just cylindrical.

[0036] Referring to Figure 5(c), ring-shaped permanent magnets 33 are arranged to surround each of the two end faces 11a of the U-shaped yoke 11. The permanent magnets 33 prevent magnetic flux from leaking out from the end faces 11a of the yoke 11 and spreading throughout the plate-shaped member 100. The permanent magnets 33 are not limited to a circular ring shape, but can be any closed curve in the shape of a strip. Examples of closed curves include triangles, squares, and star shapes. The permanent magnets 33 may be arranged in a double or triple row of ring-shaped permanent magnets of different diameters surrounding the end faces 11a of the yoke 11. This allows for more efficient wireless power transfer than when only one permanent magnet 30 is arranged.

[0037] In Figures 5(b) and (c), the permanent magnets are arranged to surround both end faces 11a of the yoke 11, but they may also be arranged to surround only one end face 11a. This reduces the transmission efficiency compared to installing them on both ends, but it reduces the cost of the permanent magnet on one end. In Figure 5(c), a closed-curve permanent magnet, such as a ring-shaped permanent magnet, is shown, but a permanent magnet with a portion of the closed curve missing may also be used. In such a case, the missing portion of the permanent magnet should be oriented in the opposite direction to the other end face 11a of the yoke 11. This maintains the effect of suppressing the spread of magnetic flux. In particular, the width of the missing portion of the permanent magnet may be made larger than the width of the end of the yoke 11. This allows the permanent magnet to be retrofitted to an already installed yoke 11, reducing the effort and cost of disassembly that would be required when adding it to an already installed yoke 11.

[0038] In Figures 3, 4, and 5, the permanent magnets 30, 33 and the permanent magnet groups 31, 32 are arranged on the coil 10 side of the plate-shaped member 100, but they may also be arranged on the coil 20 side. This allows a larger external magnetic field to be applied to the plate-shaped member 100, enabling efficient wireless power transmission.

[0039] Figure 6 is a schematic cross-sectional view of a modified wireless power supply communication device of the first embodiment. Referring to Figure 6(a), the wireless power supply communication device 40 has two permanent magnets 30 facing each other on the coil 10 side surface and the coil 20 side surface of the plate-shaped member 100, with one having its north pole in contact with the plate-shaped member 100 and the other having its south pole in contact with the plate-shaped member 100. Most of the magnetic field emitted from the north pole of one permanent magnet 30 passes through the plate-shaped member 100 and enters the south pole of the other permanent magnet. This allows a strong magnetic field to be applied to the plate-shaped member 100. The direction of the magnetic field is approximately 90° different from the direction of the magnetic flux that leaks and spreads from the yoke 11 into the plate-shaped member 100. Even in this state, the magnetic resistance can be increased.

[0040] Referring to Figure 6(b), the wireless power transmission communication device 50 has two permanent magnets 30 facing each other on the coil 10 side surface and the coil 20 side surface of the plate-shaped member 100, with both magnets having the same north pole in contact with the plate-shaped member 100. The magnetic field emitted from the north pole of each permanent magnet 30 leaks into the plate-shaped member 100 and spreads in the planar direction. The magnetic flux spreading from the yoke 11 to the plate-shaped member 100 due to the magnetic field generated by the coil 11 during power transmission flows along the planar direction of the plate-shaped member 100, so it is in the same direction as the magnetic flux from the permanent magnets 30, making it easier for the plate-shaped member 100 to reach magnetic saturation. As a result, the transmission efficiency of the wireless power transmission communication device 50 is improved. Thus, the transmission efficiency is improved when permanent magnets 30 with the same poles face each other compared to when permanent magnets 30 with different poles face each other, as shown in Figure 6(a).

[0041] In the first and second embodiments described above, the permanent magnets 30, 33 and the permanent magnet groups 31, 32 were attached to the ferromagnetic plate-shaped member 100 by magnetic force. However, the fixing means is not limited to magnetic force, and adhesives, double-sided tape, screws, or fixing jigs may also be used. In particular, if permanent magnets are arranged so that they face each other on both sides of the plate-shaped member 100, and the same poles face each other relative to the plate-shaped member 100, magnetic force may not be able to fix them due to repulsive forces. In that case, it is advisable to fix the permanent magnets with adhesives, double-sided tape, screws, or fixing jigs.

[0042] <Third Embodiment> The wireless power transmission communication device according to the third embodiment is equipped with an electromagnetic coil, such as a solenoid coil or electromagnet, instead of a permanent magnet as a means of applying a magnetic field to a plate-shaped member. Otherwise, it is the same as the first or second embodiment. This makes it possible to electrically change the transmission efficiency of wireless power transmission by a signal input to the electromagnetic coil, to achieve efficient wireless power transmission even at high temperatures where permanent magnets lose their magnetism, and to achieve efficient wireless power transmission even on thick iron plates by generating a magnetic field stronger than that of a permanent magnet.

[0043] Figure 7 is a schematic cross-sectional view of a wireless power transmission communication device according to the third embodiment. Referring to Figure 7(a), the wireless power transmission communication device 50 has a solenoid coil 51 instead of a permanent magnet, and the solenoid coil 51 is positioned between the two ends of a U-shaped yoke 11, with the magnetic field inlet and outlet facing the plate-shaped member 100. DC, AC with a DC bias, or AC is input to the solenoid coil 51. As a result, a magnetic saturation state occurs in the plate-shaped member 100, similar to when a permanent magnet is placed, increasing the magnetic resistance and reducing the magnetic flux leaking to the plate-shaped member 100, thereby realizing wireless power transmission communication with good transmission efficiency. When using a solenoid coil 51, although the cost and energy increase compared to when a permanent magnet is used, it is possible to generate a larger magnetic field than with a permanent magnet by flowing a large current, and wireless power transmission communication becomes possible even when the plate-shaped member 100 is a thick iron plate or the like.

[0044] Referring to Figure 7(b), the wireless power transmission communication device 60 has an electromagnet 61 with a U-shaped yoke. Since the electromagnet 61 has two end faces of its yoke, it can utilize magnetic flux from opposite poles compared to the solenoid coil 51, enabling wireless power transmission communication with good transmission efficiency. The electromagnet 61 may also have a shape in which the end faces of its U-shaped yoke surround the end faces of the yoke 11. This reduces the magnetic flux that leaks out from the end faces of the yoke 11 to the plate-shaped member 100, enabling wireless power transmission communication with good transmission efficiency.

[0045] <Fourth Embodiment> The wireless power supply communication device according to the fourth embodiment communicates by modulating the external magnetic field that the magnetic field application means applies to the plate-shaped member. Conventionally, in wireless power supply communication devices that use a ferromagnetic plate-shaped member, communication is performed by modulating the amplitude or phase of the AC current input to the coil used for power supply, or the impedance of the circuit. However, in the wireless power supply communication device of the fourth embodiment, communication is performed by modulating the external magnetic field that the magnetic field application means applies to the plate-shaped member.

[0046] Figure 8 is a schematic cross-sectional view of a wireless power supply communication device according to the fourth embodiment. Referring to Figure 8(a), the wireless power supply communication device 70 has a permanent magnet 30 and a piezoelectric element 71 as magnetic field application means. The piezoelectric element 71 is placed between the permanent magnet 30 and the plate-shaped member 100 and has a distance modulation function. The piezoelectric element 71 expands and contracts in response to a modulated voltage signal containing communication data input from the signal input terminal 72, changing the distance between the permanent magnet 30 and the plate-shaped member 100. This changes the strength of the external magnetic field that the permanent magnet 30 applies to the plate-shaped member 100, changing the magnetoresistance of the plate-shaped member 100, and thereby modulating the transmission efficiency of wireless power supply, enabling communication. The modulation method of the modulated voltage signal may be amplitude modulation, frequency modulation, or phase modulation. The permanent magnet 30 may be arranged as shown in Figure 5, and the permanent magnet 30 on which the piezoelectric element 71 is provided may be some or all of a plurality of permanent magnets 30, and in the case of a plurality, they should be synchronized with each other.

[0047] Referring to Figure 8(b), the wireless power supply communication device 80 has a solenoid coil 81. The solenoid coil 81 applies a modulated external magnetic field to the plate-shaped member 100 in accordance with a modulated current signal containing communication data input from the signal input terminal 82. This changes the magnetic resistance of the plate-shaped member 100, modulating the transmission efficiency of the wireless power supply, thereby enabling communication. Note that an electromagnet may be used instead of the solenoid coil 81.

[0048] <Fifth Embodiment> The fifth embodiment of the wireless power supply communication device has a flexible thin-film ferromagnetic material provided between the end face of the yoke and the plate-shaped member, and between the permanent magnet and the plate-shaped member. This reduces the magnetic resistance caused by the air gap resulting from the roughness of the end face of the yoke, the surface of the plate-shaped member, and the surface of the permanent magnet, for example, the magnetic resistance R between the end face of the yoke and the plate-shaped member shown in Figure 4. mg Reduce the same amount.

[0049] Figure 9 is a schematic cross-sectional view of a wireless power supply communication device according to the fifth embodiment. Referring to Figure 9, the wireless power supply communication device 90 has a flexible high-permeability material 91 provided between the end face of the yoke 11 and the plate-shaped member 100, between the end face of the yoke 11 and the plate-shaped member 100, and between the permanent magnet 30 and the plate-shaped member 100. The flexible high-permeability material 91 is a paste or resin material with high permeability, for example, a magnetic paste containing magnetic particles in a binder resin. The relative permeability of the flexible high-permeability material 91 is preferably 100 or more, and more preferably 1000 or more. When the yoke 11 is a ferromagnetic material, the relative permeability becomes 100 to 10000 times or more than that of air, and the magnetic resistance becomes significantly smaller. Conversely, the magnetic resistance of the air gap between the end faces of the yokes 11 and 21 and the plate-shaped member 100 has a relatively large influence. For example, if the relative permeability of the materials for yokes 11 and 21 is 10,000 and the area is the same, the magnetic resistance of an air gap with a gap width of 100 micrometers will be the same as the magnetic resistance of a yoke with a length of 1 meter. By reducing the air gap with the flexible, high-permeability material 91, wireless power transmission communication with high transmission efficiency can be realized.

[0050] <Examples> The embodiment involves measuring the transmission efficiency for various arrangements of permanent magnets, as shown in Figure 5, in the configuration of the wireless power supply communication device shown in Figure 6.

[0051] Figure 10 shows the arrangement of permanent magnets in the embodiment, illustrating the relationship between the permanent magnets (cylindrical magnets are shown as small circles, and ring-shaped magnets as rings) and the end face of the yoke (shown as a rectangle). Figure 10 shows the arrangement on one side, for example, the surface of the plate-shaped member (iron plate) on the primary coil side, but the arrangement on the other side, for example, the surface of the plate-shaped member (iron plate) on the secondary coil side, is similar.

[0052] Coils 10 and 20 have 230 turns on the primary side and 430 turns on the secondary side. Yokes 11 and 21 are made by laminating 23 layers of non-oriented electrical steel sheet (50JN350) with a thickness of approximately 0.5 mm. The distance between the centers of the end faces of the two yokes is 56 mm, and the size of the end faces is 16 mm wide and 12 mm long. To insert the coils, the yokes were split in half in the middle and joined with tape. The permanent magnets are cylindrical neodymium magnets with a diameter of 6 mm, a thickness of 3 mm, and a magnetic force of 230 mT (specified value at the magnetic pole surface), and ring-shaped magnets with an outer diameter of 26 mm, an inner diameter of 20 mm, a width of 3 mm, and a magnetic force of 527.6 mT (manufactured by Magfine). The iron plate used as plate member 100 is SPCC material according to JIS G3141, with a width of 100 mm, a length of 275 mm, and a thickness of 0.6 mm.

[0053] The permanent magnets were positioned so that they faced each other on the primary coil side (front) and secondary coil side (back) of the iron plate. Power transmission efficiency was measured for two cases: when the polarities of the opposing permanent magnets were the same (for example, both were north poles) and when they were different (for example, the front was north pole and the back was south pole). The relationship when the polarities in contact with the iron plate were the same is called "like poles," and the relationship when the polarities in contact with the iron plate were different is called "opposite poles."

[0054] Referring to Figure 10(a), five permanent magnets were arranged in a single row on the median of the line segment connecting the end faces of the two yokes. This arrangement was designated as Example 1 and Example 2. Referring to Figure 10(b), eight permanent magnets were arranged at equal angular intervals on the closed curves surrounding each of the end faces of the two yokes. This arrangement was designated as Example 3. Referring to Figure 10(c), permanent magnets were arranged at equal angular intervals on two closed curves of different radii surrounding each of the end faces of the two yokes. Eight magnets were placed on the inner closed curve and twelve on the outer closed curve. This arrangement was designated as Example 4. Referring to Figure 10(d), the permanent magnets were ring-shaped magnets surrounding each of the end faces of the two yokes. This arrangement was designated as Example 5. Referring to Figure 10(e), five permanent magnets were arranged in two rows along the median of the line segment connecting the end faces of the two yokes. This arrangement was designated as Examples 6 to 9. The comparative example is an example that does not use a permanent magnet, but otherwise has the same configuration as Examples 1 to 9.

[0055] The input signal to the primary coil of the wireless power transfer communication device was mainly 1 kHz in frequency, generated by a function generator (Tektronix, model AFG3022B), and amplified 7.7 times by a power amplifier (homemade, voltage range ±23V). A 1 kΩ metal film resistor was connected as a load to the secondary coil of the wireless power transfer communication device. The input power of the primary coil and the output power of the secondary coil were measured using a power meter (Rohde & Schwarz, model HMC8015). Transmission efficiency was calculated as output power / input power × 100 (%).

[0056] Figure 11 shows the power transmission efficiency of the examples and comparative examples (part 1), and Figure 12 shows the power transmission efficiency of the examples (part 2). Referring to Figures 11 and 12, it can be seen that the power transmission efficiency of all Examples 1 to 9 exceeds that of the comparative example, which has a power transmission efficiency of 2.39%. This can be seen as the permanent magnets causing the iron plate to reach a saturated magnetization state, which suppresses the leakage and spread of the magnetic flux generated from the primary yoke for power supply into the iron plate, allowing more of it to flow through the secondary yoke.

[0057] Comparing Example 1 and Example 2, the efficiency was 2.87% when the polarity relationship between the permanent magnets on the front and back surfaces was the same (Example 1), and 2.60% when they were opposite (Example 2), indicating that the same-polarity case was better. This is thought to be because, in the case of same polarity, the magnetic flux emanating from the same poles spreads within the iron plate in a way that repels each other, saturating the magnetization state in the area through which the magnetic flux from the primary side yoke passes due to power supply, thus greatly improving efficiency. This is also true for the relationship between Example 6 and Example 7, and between Example 8 and Example 9, indicating that the same-polarity case improves power transmission efficiency.

[0058] Comparing Example 3 and Example 4, it can be seen that, in the case of the same polarity, when permanent magnets are arranged to surround the end face of the yoke, the transmission efficiency is higher when they are arranged in a double configuration (Example 4) than when they are arranged in a single configuration (Example 3). It is thought that the effect of improving efficiency is even greater when they are arranged in a double configuration because the area that reaches a magnetic saturation state is larger.

[0059] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and include design modifications and the like that that do not depart from the spirit of this invention. For example, the above embodiments have been described in detail to make the present disclosure easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace some of the configurations of an embodiment with the configurations of another embodiment, and it is also possible to add, delete, or replace other configurations in an embodiment.

[0060] Furthermore, "approximately" is a concept that includes not only cases where something is strictly identical, but also errors or deformations that do not cause a loss of identity. For example, "cylindrical shape" is not limited to cases where something is strictly cylindrical, but also includes cases where it can be considered identical to a cylindrical shape. Also, for example, when simply using terms such as orthogonal, parallel, or coincident, it should include not only cases where something is strictly orthogonal, parallel, or coincident, but also cases where something is approximately parallel, approximately orthogonal, or approximately coincident. [Explanation of Symbols]

[0061] 1, 40, 41, 50, 60, 70, 80, 90 Wireless power supply and communication equipment 10,20 coils 11,21 York 11a End face of yoke 30 permanent magnets 31,32 Permanent magnet group 33 Ring-shaped magnets 51,81 Solenoid coil 61 Electromagnet 71 Piezoelectric element

Claims

1. A first coil having a U-shaped, V-shaped, or U-shaped first yoke is positioned opposite a ferromagnetic plate-shaped member, and a second coil having a U-shaped, V-shaped, or U-shaped second yoke is positioned. A power supply unit that supplies power to the first coil, A means for applying a magnetic field, The two end faces of the first yoke of the first coil and the two end faces of the second yoke of the second coil are arranged to face each other with the plate-shaped member in between. The magnetic field applying means is capable of applying a magnetic field to the plate-shaped member between the two end faces of at least one of the first yoke and the second yoke in a wireless power supply communication device.

2. The wireless power supply communication device according to claim 1, wherein the magnetic field applying means is one or more permanent magnets.

3. The wireless power supply communication device according to claim 2, wherein the permanent magnet is disposed on the surface of the plate-shaped member on the first coil side, between one of the two end faces of the first yoke and the other.

4. The wireless power supply communication device according to claim 2, wherein a plurality of permanent magnets are arranged on the surface of the plate-shaped member on the first coil side, on a straight line that intersects with the line segment connecting the two end faces of the first yoke.

5. The wireless power supply communication device according to claim 4, wherein a plurality of permanent magnets are arranged on the second coil side surface of the plate-shaped member so as to face the plurality of permanent magnets arranged on the first coil side surface.

6. The wireless power supply communication device according to claim 5, wherein the plurality of permanent magnets arranged on the front first coil side and the plurality of permanent magnets arranged on the front second coil side have the same poles in contact with the plate-shaped member.

7. The wireless power supply communication device according to claim 5, wherein the plurality of permanent magnets arranged on the front first coil side and the plurality of permanent magnets arranged on the front second coil side have opposite poles in contact with the plate-shaped member.

8. The wireless power supply communication device according to claim 2, wherein a plurality of permanent magnets are arranged so as to surround at least one of the two end faces of the first yoke of the first coil.

9. The wireless power supply communication device according to claim 2, wherein a plurality of the permanent magnets are arranged on a closed curve that surrounds at least one of the two end faces of the first yoke of the first coil.

10. The wireless power supply communication device according to claim 9, wherein a plurality of permanent magnets are arranged on the second coil side surface of the plate-shaped member so as to face the plurality of permanent magnets arranged on the first coil side surface.

11. The wireless power supply communication device according to claim 10, wherein the plurality of permanent magnets arranged on the front first coil side and the plurality of permanent magnets arranged on the front second coil side have the same poles in contact with the plate-shaped member.

12. The wireless power supply communication device according to claim 10, wherein the plurality of permanent magnets arranged on the front first coil side and the plurality of permanent magnets arranged on the front second coil side have opposite poles in contact with the plate-shaped member.

13. The wireless power supply communication device according to claim 2, wherein the permanent magnet is a ring-shaped permanent magnet surrounding at least one of the two end faces of the first yoke of the first coil.

14. The wireless power supply communication device according to claim 2, wherein a flexible, thin ferromagnetic material is further disposed between the end face of the first yoke and the plate-like member, between the end face of the second yoke and the plate-like member, and between the permanent magnet and the plate-like member.

15. The wireless power supply communication device according to claim 1, wherein the magnetic field applying means is a third coil or an electromagnet.

16. The wireless power supply communication device according to claim 1, wherein the magnetic field application means is configured to modulate the strength of the magnetic field applied to the plate-shaped member.

17. The magnetic field applying means is one or more permanent magnets, A distance modulation section is further provided between the permanent magnet and the plate-shaped member. The wireless power supply communication device according to claim 16, wherein the distance modulation unit modulates the strength of the magnetic field applied from the permanent magnet to the plate-shaped member by changing the distance between the permanent magnet and the plate-shaped member based on the input signal, thereby modulating the transmission efficiency of the wireless power supply, and the wireless power supply communication device performs wireless communication.

18. The magnetic field applying means is a third coil or an electromagnet. The wireless power supply communication device according to claim 16, wherein the third coil or electromagnet modulates the strength of the magnetic field applied in the plate-shaped member in accordance with the input current modulated based on the signal, thereby modulating the transmission efficiency of the wireless power supply, and the wireless power supply communication device performs wireless communication.

19. The wireless power supply communication device according to claim 1, further comprising a flexible, highly permeable material disposed between the two end faces of the first yoke and the plate-like member, between the two end faces of the second yoke and the plate-like member, and between the magnetic field applying means and the plate-like member.

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