Wireless power supply device and wireless power supply method

Abstract

To provide a wireless power supply device and a wireless power supply method that can suppress cost increases.SOLUTION: A wireless power supply device includes a high frequency power source, an exciter, and a feeding resonator, and the exciter has a first excitation coil, the first excitation coil is electrically connected to the high frequency power source, the feeding resonator has at least three feeding coils, and the feeding coils are arranged substantially radially or radially along the radial direction of a predetermined reference axis, and the feeding coils have the same resonance frequency, and by combining them, a vibration mode having a predetermined mode frequency is generated, and the high frequency power source supplies power at a frequency corresponding to the mode frequency of the vibration mode to the first excitation coil to excite the feeding resonator and cause the feeding coil to resonate in the vibration mode.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wireless power supply device and a wireless power supply method.

Background Art

[0002] With the spread of the Internet of Things (IoT), various devices have come to be connected to the Internet. These devices require regular charging or battery replacement, and the problem of the cost of power supply has become apparent. Therefore, in recent years, wireless power transfer (WPT) to devices at any position in three-dimensional space has attracted attention. Among WPT, there is a microwave power transmission method. While this method can supply power through three-dimensional space, it has a problem that the efficiency is very poor and it cannot supply a large amount of power. In contrast, a method has been proposed in which a cavity resonator often used for microwave filters and the like is expanded to a room size, and a large amount of power is transmitted over a wide range inside the room (inside the cavity resonator) (see, for example, Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology described in Non-Patent Document 1 requires enlarging the size of the metal cavity resonator and surrounding the space where wireless power transfer is to be realized with the cavity resonator, which presents cost challenges.

[0005] This invention has been made in view of these circumstances, and aims to provide a wireless power supply device and a wireless power supply method that can suppress cost increases. [Means for solving the problem]

[0006] According to the present invention, a wireless power supply device is provided, comprising a high-frequency power supply, an exciter, and a power supply resonator, wherein the exciter has a first excitation coil, the first excitation coil is electrically connected to the high-frequency power supply, the power supply resonator has at least three power supply coils, the power supply coils are arranged substantially radially or radially along the radial direction of a predetermined reference axis, the power supply coils have the same resonant frequency, and by coupling them, a vibration mode having a predetermined mode frequency is generated, and the high-frequency power supply is configured to supply power to the first excitation coil at a frequency corresponding to the mode frequency of the vibration mode to excite the power supply resonator and cause the power supply coil to resonate in the vibration mode.

[0007] According to the present invention, a method of wireless power transmission is performed by generating a magnetic field by causing at least three power supply coils, which are arranged substantially radially or radially along the radial direction of a predetermined reference axis, to resonate in a vibration mode having a predetermined mode frequency. This eliminates the need for a cavity resonator that is as large as a room, as it is sufficient to place the coils in the target space, thus suppressing cost increases.

[0008] The following are examples of various embodiments of the present invention. The embodiments shown below can be combined with each other. Preferably, the power supply coil is formed in a planar or smooth curved shape, and a wireless power supply device is provided. Preferably, the wireless power supply device is provided, which supplies power to the first excitation coil such that the high-frequency power supply resonates in the vibration mode such that, when each of the power supply coils is viewed from the front, a current flows in the same direction through each of the power supply coils. Preferably, the high-frequency power supply is provided as a wireless power supply device that changes the frequency of the power supplied to the first excitation coil so that the power supply coil resonates in a plurality of vibration modes in which the direction of the generated magnetic field is different. Preferably, the power supply resonator is provided as a wireless power supply device having four power supply coils. Preferably, a wireless power supply device is provided in which the first excitation coil is located inside the power supply coil. Preferably, the exciter further comprises a second excitation coil, the first excitation coil being positioned between an adjacent pair of the power supply coils in the circumferential direction of the reference axis, the second excitation coil being positioned between a pair of power supply coils different from the pair of power supply coils that sandwich the first excitation coil in the circumferential direction of the reference axis, and the second excitation coil being positioned substantially or perpendicular to the first excitation coil, the wireless power supply device is provided. Preferably, the high-frequency power supply is provided as a wireless power supply device that alternately supplies power to the first and second excitation coils. Preferably, the wireless power supply device is provided in which the high-frequency power supply simultaneously supplies power to the first and second excitation coils, and the power supplied to the first excitation coil and the power supplied to the second excitation coil have a predetermined phase difference. Preferably, the wireless power supply device is provided in which the power supply coil is composed of a spiral coil having a triangular, parallelogram, rectangular, polygonal, circular, or combination thereof shape in plan view. Preferably, a wireless power supply device is provided, further comprising at least three partitions, each of which is provided with a power supply coil. According to another aspect of embodiments of the present invention, a wireless power supply method is provided using a high-frequency power supply, an exciter, and a power supply resonator, comprising a resonance step, wherein the exciter has a first excitation coil, the first excitation coil is electrically connected to the high-frequency power supply, the power supply resonator has at least three power supply coils, the power supply coils are arranged substantially radially or radially along the radial direction on a predetermined reference axis, the power supply coils have the same resonant frequency, and by coupling them, a vibration mode having a predetermined mode frequency is generated, and in the resonance step, the high-frequency power supply supplies power to the first excitation coil at a frequency corresponding to the mode frequency of the vibration mode to excite the power supply resonator, causing the power supply coil to resonate in the vibration mode. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the overall configuration of the wireless power supply device 100 according to the embodiment. [Figure 2] Figure 2A is a perspective view of partitions p1 to p3 shown in Figure 1. Figure 2B is a perspective view showing the state after removing partitions p1 to p3 shown in Figure 2A, exposing the power supply coils 31 to 33 and the excitation coil 21. [Figure 3] Figure 3 is a plan view of the power supply coil 31 and the excitation coil 21. [Figure 4]Figure 4A is a distribution map showing the magnetic field strength in this vibration mode, based on calculation results from an electromagnetic field simulator (feed coil height 90cm, width 90cm). In Figure 4A, the magnetic field strength in the horizontal plane at the center of the height direction of feed coils 31-33 (coordinate z2 in Figure 3) is shown. In Figure 4A, darker colors indicate stronger magnetic fields, and the symbol Sg1 indicates the direction of the current passing through coil section X1 shown in Figure 3, while the symbol Sg2 indicates the direction of the current passing through coil section X2 shown in Figure 3 (the same applies to Figure 6 and others below). Figure 4B is a distribution map showing the magnetic field strength and direction of the magnetic field for the vibration mode shown in Figure 4A, based on calculation results from the electromagnetic field simulator, in the same horizontal plane as Figure 4A. In Figure 4B, the direction of the arrows indicates the direction of the magnetic field at each location, and the darker the color of the arrow, the stronger the magnetic field (the same applies to Figure 6 and others below). [Figure 5] Figure 5A shows the strength of the horizontal magnetic field at a position 15 cm above the center of the power supply coils 31-33 in the height direction. Figure 5B shows the strength of the horizontal magnetic field at a position 30 cm above the center of the power supply coils 31-33 in the height direction. [Figure 6] Figure 6A is a distribution diagram showing the magnetic field strength in a vibration mode different from that shown in Figures 4A and 4B (where the frequency is higher than that of the vibration modes in Figures 4A and 4B), based on calculations by the electromagnetic field simulator. Figure 6A shows the magnetic field strength in the horizontal plane at the center of the height direction of the feed coils 31-33. Figure 6B is a distribution diagram showing the magnetic field strength and direction of the magnetic field for the vibration modes shown in Figure 6A, in the same horizontal plane as Figure 6A, based on calculations by the electromagnetic field simulator. [Figure 7] Figure 7 is a schematic diagram showing the overall configuration of a modified example 1 of the wireless power supply device 100 according to the embodiment. [Figure 8] Figure 8A is a perspective view of partitions p1 to p4 shown in Figure 7. Figure 8B is a perspective view showing the state after removing partitions p1 to p4 shown in Figure 8A, exposing the power supply coils 31 to 34 and the excitation coil 21. [Figure 9]Figures 9A to 9D are calculation results from an electromagnetic field simulator and are distribution diagrams showing the magnetic field strength in four vibration modes (from lowest to highest frequency, as shown in Figures 9A, 9B, 9C, and 9D). Figures 9A to 9D show the magnetic field strength in the horizontal plane at the center of the height direction of the feed coils 31 to 34. [Figure 10] Figures 10A to 10D are calculation results from an electromagnetic field simulator, and are distribution diagrams showing the magnetic field strength and direction of the vibration modes shown in Figures 9A to 9D, in the same horizontal plane as Figures 9A to 9D. [Figure 11] Figure 11 is a schematic diagram showing the overall configuration of a modified example 2 of the wireless power supply device 100 according to the embodiment. [Figure 12] Figure 12A is a distribution diagram showing the magnetic field strength when the excitation coil 21 is in use, based on the calculation results of the electromagnetic field simulator. Figure 12B is a distribution diagram showing the magnetic field strength and direction of the vibration mode shown in Figure 12A, in the same horizontal plane as Figure 12A, based on the calculation results of the electromagnetic field simulator. Figure 12C is a distribution diagram showing the magnetic field strength when the excitation coil 22 is in use, based on the calculation results of the electromagnetic field simulator. Figure 12D is a distribution diagram showing the magnetic field strength and direction of the vibration mode shown in Figure 12C, in the same horizontal plane as Figure 12C, based on the calculation results of the electromagnetic field simulator. Figures 12A and 12C show the magnetic field strength in the horizontal plane at the center position in the height direction of the power supply coils 31 to 34. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. The various features shown in the embodiments below can be combined with each other. Furthermore, each feature constitutes an independent invention.

[0011] 1. Embodiment 1-1 Overall Structure Explanation As shown in FIGS. 1 and 2A, the wireless power supply device 100 according to the embodiment is applied to, for example, a partition (a partition board that divides the internal space of a building) arranged in a space such as an office. As shown in FIGS. 1 to 2B, the wireless power supply device 100 includes a high-frequency power source 1, an exciter 2, a power supply resonator 3, and partitions p1 to p3. The wireless power supply device 100 adopts a magnetic field coupling method that can charge various devices to be charged (devices on the power receiving side) across a three-dimensional space. The various devices to be charged are, for example, electrical appliances (such as mobile phones, personal computers, lighting, etc.) arranged in an office or the like. In the embodiment, the wireless power supply device 100 is described as being applied to a partition, but it is not limited thereto. For example, it may be applied to a factory and used for power supply to power tools in the factory. In addition, the embodiment can also be applied to non-contact power supply to various sensors essential for the IoT society and non-contact power supply to in-vivo medical devices such as capsule endoscopes.

[0012] The wireless power supply device 100 can couple (electromagnetically couple) a plurality of power supply coils (power supply coils 31 to 33 described later). When the plurality of power supply coils are coupled, a plurality of vibration modes having different mode frequencies are generated in the plurality of power supply coils. Specifically, the wireless power supply device 100 can generate vibration modes as shown in FIGS. 4A and 4B and vibration modes as shown in FIGS. 6A and 6B by using the excitation coil 21.

[0013] 1-2 High-frequency power source 1 As shown in FIG. 1, the high-frequency power source 1 is configured to excite the power supply resonator 3 via the exciter 2. That is, the high-frequency power source 1 outputs its output signal to the exciter 2, and the exciter 2 is electromagnetically coupled to the power supply resonator 3. The high-frequency power source 1 is connected to the excitation coil 21 of the exciter 2 described later. The control of the high-frequency power source 1 is controlled by a control device not shown.

[0014] 1-3 Exciter 2 As shown in Figures 2B and 3, the exciter 2 is equipped with an excitation coil 21. The excitation coil 21 is electrically connected to the high-frequency power supply 1 and is configured to receive high-frequency AC power. The excitation coil 21 is an example of a first excitation coil. The excitation coil 21 has the function of exciting the power supply coils 31 to 33. In other words, when the high-frequency power supply 1 supplies power to the excitation coil 21 at a frequency corresponding to the mode frequency of the vibration mode, the power supply coils 31 to 33 are excited.

[0015] The configuration (shape) of the excitation coil 21 is not particularly limited, but it is preferable that it has a shape and size that facilitates the formation of electromagnetic field coupling with the power supply coils 31 to 33, which will be described later. In the embodiment, the shape of the excitation coil 21 is circular. Also in the embodiment, the excitation coil 21 is positioned inside one of the power supply coils (power supply coil 31 in the embodiment). In other words, the excitation coil 21 is positioned so that it is surrounded by the power supply coil 31. Furthermore, the excitation coil 21 is positioned on the same plane as the power supply coil 31. Moreover, in the embodiment, the center position of the excitation coil 21 coincides with or approximately coincides with the center position of the power supply coil 31.

[0016] 1-4 Power supply resonator 3 As shown in Figures 2B and 3, the power supply resonator 3 is equipped with power supply coils 31 to 33. Each power supply coil 31 to 33 has the same configuration (shape) and the same resonant frequency. The wireless power supply device 100 is also capable of coupling the power supply coils 31 to 33 (electromagnetic field coupling), and when the power supply coils 31 to 33 are coupled, vibration modes with different resonant frequencies are generated in the power supply coils 31 to 33. Specifically, it is possible to generate vibration modes with lower resonant frequencies (Figures 4A and 4B: resonant frequency is, for example, 1.57 MHz) and vibration modes with higher resonant frequencies (Figures 6A and 6B: resonant frequency is, for example, 1.64 MHz).

[0017] In this embodiment, the configuration (shape) of each power supply coil 31 to 33 is the same, so the shape of the power supply coil will be explained using power supply coil 31 as an example. As shown in Figure 3, the power supply coil 31 can be formed in a planar shape or a smooth curved shape. In this embodiment, the power supply coil 31 is formed in a planar shape. Furthermore, the power supply coil 31 can be a coil having a triangular, parallelogram, rectangular, polygonal, circular, or combination thereof shape in plan view. In this embodiment, the power supply coil 31 has a rectangular shape in plan view, which can suppress unevenness in the magnetic field strength of region Sp1 in the height direction (see Figures 4A, 5A, and 5B). Moreover, each power supply coil 31 is a spiral coil. That is, the power supply coil 31 is a coil formed by winding a conductor in a spiral shape in plan view. In other words, the power supply coil 31 is a non-annular coil having an inner end s and an outer end t. In this embodiment, as shown in Figure 3, the winding direction of the conductor of the power supply coil 31 is clockwise from the outer end t to the inner end s.

[0018] The reference axis O (center position) of the radially arranged partitions p1 to p3 can be defined as the vertical axis at the point where three imaginary lines intersect when each imaginary line is drawn overlapping the entirety of each partition p1 to p3, when the partitions p1 to p3 are viewed from above.

[0019] As shown in Figure 1, the power supply coils 31 to 33 are arranged radially along the radial direction of the reference axis O. In this embodiment, the distance from the reference axis O to each power supply coil 31 to 33 (the distance from the reference axis O to the innermost conductor among each power supply coil 31 to 33) is the same. Because the power supply coils 31 to 33 are arranged radially along the radial direction of the reference axis O, the wireless power supply device 100 can generate a uniform magnetic field in a desired region in the space Sp inside the power supply coils 31 to 33, and can effectively supply power. The wireless power supply device 100 is configured to perform multiple vibration modes, but in particular the vibration modes shown in Figures 4A and 4B, a concentrated and uniform magnetic field can be formed in the region Sp1 closer to the reference axis O within the space Sp between partitions p1 to p3. Furthermore, the power supply coils 31 to 33 do not necessarily have to be arranged perfectly radially along the radial direction of the reference axis O. In other words, the power supply coils 31 to 33 may be arranged substantially radially (not parallel to the radial direction of the reference axis O, but offset from that radial direction).

[0020] As shown in Figure 2B, each of the power supply coils 31 to 33 is arranged so as to be at equal angles with respect to the reference axis O. That is, power supply coil 31 and power supply coil 32 are arranged so as to form a 120-degree angle. Similarly, the angle between power supply coil 32 and power supply coil 33, and the angle between power supply coil 32 and power supply coil 33 are also 120 degrees. In this embodiment, the power supply coils 31 to 33 are described as being arranged at equal angles (120 degrees) around the reference axis O, but the invention is not limited to this. There may be some variation in the angles formed by each power supply coil. Specifically, the angles formed by each power supply coil 31 to 33 may be, for example, 100, 105, 110, 115, 120, 125, 130, 135, 140, and may be within the range of any two of the values ​​exemplified here. In other words, for example, power supply coil 31 and power supply coil 32 may form a 100-degree angle, power supply coil 32 and power supply coil 33 may form a 100-degree angle, and power supply coil 33 and power supply coil 31 may form a 160-degree angle. Furthermore, for example, the power supply coil 31 and power supply coil 32 may be at a 90-degree angle, the power supply coil 32 and power supply coil 33 may be at a 90-degree angle, and the power supply coil 33 and power supply coil 31 may be at a 180-degree angle.

[0021] Next, we will explain the various dimensions of the power supply coil 31 and the excitation coil 21 and their positional relationship with respect to the reference axis O. By using the configuration described below, we can expect to particularly localize the magnetic field generated in the vibration modes shown in Figures 4A and 4B in region Sp1. Since the same applies to the power supply coils 32 and 33, we will only discuss the power supply coil 31 here. As shown in Figure 3, we define a radial coordinate system r and a vertical coordinate system z. At this time, the various coordinates shown in Figure 3 are as follows. Note that coordinate system r is the coordinate system extending horizontally from the reference axis O. Also, coordinate system z is superimposed on the reference axis O. The coordinate r0 corresponds to the reference axis O in the coordinate system r. • Coordinate r1 corresponds to the position of the innermost part of the power supply coil 31 in coordinate system r. • Coordinate r2 corresponds to the center position C of the excitation coil 21 in coordinate system r. • Coordinate r3 corresponds to the position of the outermost part of the power supply coil 31 in coordinate system r. • Coordinate z0 corresponds to the height position of the mounting surface of partitions p1 to p3. The coordinate z1 corresponds to the height position of the lower end of the power supply coil 31. The coordinate z2 corresponds to the height position C of the excitation coil 21. The coordinate z3 corresponds to the height position of the upper end of the power supply coil 31.

[0022] The vertical width of the power supply coil 31 (the difference between coordinate z3 and coordinate z1) is specifically, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150 (cm), and may also be within the range of any two of the values ​​exemplified here. The width of the power supply coil 31 (the difference between coordinates r3 and r1) is specifically, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150 (cm), and may also be within the range of any two of the values ​​exemplified here. In this embodiment, the vertical width and horizontal width of the power supply coil 31 are described as being approximately the same, but the embodiment is not limited to this and may be different.

[0023] The distance from the reference axis O to the power supply coil 31 (the difference between coordinates r1 and r0) is specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 (cm), and may also be within the range of any two of the values ​​exemplified here. The distance from the mounting surface to the lower end of the power supply coil 31 (the difference between coordinates z1 and z0) is specifically, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 (cm), and may also be within the range of any two of the values ​​exemplified here.

[0024] The distance from the reference axis O to the center position C (the difference between coordinates r2 and r0) is specifically, for example, 26, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105 (cm), and may also be within the range of any two of the values ​​exemplified here. The distance from the contact surface to the center position C (the difference between coordinates z2 and z0) is specifically, for example, 55, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200 (cm), and may also be within the range of any two of the values ​​exemplified here.

[0025] The number of turns of the power supply coil 31 can be, for example, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 82, 86, 90, 94, or 98, and may be within the range of any two of the values ​​exemplified here. The spacing (pitch) between the wires constituting the power supply coil 31 is, specifically, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 (mm), and may be within the range of any two of the values ​​exemplified here. The spacing (pitch) between the wires constituting the power supply coil 31 may be uniform or non-uniform. If the spacing (pitch) between the wires constituting the power supply coil 31 is non-uniform, it is sufficient that each pitch falls within the range of any two of the values ​​exemplified above. The diameter of the wires constituting the power supply coil 31 is specifically, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 (mm), and may be within the range of any two of the values ​​exemplified here.

[0026] The diameter of the excitation coil 21 is specifically, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150 (cm), and may be within the range of any two of the values ​​exemplified here. Furthermore, the diameter of the excitation coil 21 may be larger than that of the power supply coil 31.

[0027] In this embodiment, the wireless power supply device 100 is described as being applied to a partition placed in a space such as an office, and as mentioned above, the numerical values ​​are listed as examples, but it is not limited to this and may be extended to the size of a room. In this case, with respect to the vertical width of the power supply coil 31, the horizontal width of the power supply coil 31, the distance from the reference axis O to the power supply coil 31, the distance from the installation surface to the lower end of the power supply coil 31, the distance from the reference axis O to the center position C, the number of turns of the power supply coil 31, the distance between wires (pitch) constituting the power supply coil 31, and the diameter of the wires constituting the power supply coil 31, the values ​​exemplified above and the range between any two of the exemplified values ​​may be, for example, 2 times, 3 times, 4 times, or 5 times.

[0028] 1-5 Partitions p1~p3 As shown in Figures 1 to 2B, partitions p1 to p3 are configured to partition each space Sp in an office or the like. Partitions p1 to p3 consist of, for example, panels 11 to 13 and a frame (not shown) to which panels 11 to 13 are attached. Partition p1 contains a power supply coil 31 and an excitation coil 21, while partitions p2 and p3 contain power supply coils 32 and 33. Since the power supply coils 31 to 33 cannot be fixed to a highly conductive material (such as metal), each partition p1 to p3 may be equipped with a fixing member made of a dielectric material. The fixing member is provided in each partition p1 to p3 and has the function of holding the power supply coils 31 to 33 and the excitation coil 21.

[0029] 1-6 Other components: Power receiving equipment The receiving device (various devices to be charged) is equipped with a coil (resonator) not shown. When the receiving device is placed in space Sp, the coil of the receiving device couples with the magnetic field formed by the feed coils 31-33 of the feed resonator 3. As a result, the power from the high-frequency power supply 1 is transmitted to the receiving device via the excitation coil and the feed coil. Note that, in supplying power to the receiving device, the coil of the receiving device does not necessarily need to resonate with the feed coils 31-33; power may be supplied by electromagnetic induction.

[0030] 2. Description of vibration modes The wireless power supply device 100 is configured to perform a resonance step. In the resonance step, the high-frequency power supply 1 supplies power at a frequency corresponding to the mode frequency of the vibration mode described above to the excitation coil 21 to excite the power supply resonator 3, causing the power supply coils 31 to 33 to resonate in that vibration mode.

[0031] 2-1 Modes that generate a concentrated magnetic field in the region closer to the reference axis O (Figures 4A and 4B) The vibration modes shown in Figures 4A and 4B can generate a concentrated magnetic field in the region Sp1 of space Sp closer to the reference axis O. As shown in Figure 4A, the direction of the current flowing through each of the feed coils 31 to 33 is the same. In other words, the high-frequency power supply 1 supplies the desired high-frequency power to the excitation coil 21 such that the feed coils 31 to 33 resonate in a vibration mode in which, when viewed from the front, the current flows through each of the feed coils 31 to 33 in the same direction. As shown in Figures 5A and 5B, when the height of the horizontal plane changes, the overall magnetic field strength decreases slightly, but the magnetic field distribution becomes similar to that in Figure 4A. In this vibration mode, by placing a desk or electrical appliances (such as a computer) in region Sp1 shown in Figure 4A, electrical appliances in region Sp1 can be efficiently charged. Furthermore, since the human body is located in region Sp2, the magnetic field is weakened, thus preventing the magnetic field from affecting the human body.

[0032] 2-2 Mode for generating a strong magnetic field in the power supply coil 31 (Figures 6A and 6B) In the vibration modes shown in Figures 6A and 6B, a magnetic field relatively stronger than that of the power supply coils 32 and 33 can be generated in the region on the power supply coil 31 side to which the excitation coil 21 is attached. This vibration mode is effective when it is desired to suppress the magnetic field generated in the space Sp between power supply coil 32 and power supply coil 33 and to transmit power only to the space Sp between power supply coil 31 and power supply coil 32, or to the space Sp between power supply coil 31 and power supply coil 33.

[0033] Furthermore, the frequency of the power supplied to the excitation coil 21 may be changed so that the power supply coils 31-33 resonate in multiple vibration modes with different directions of generated magnetic fields. In other words, by switching between the vibration modes shown in Figures 4A and 4B and the vibration modes shown in Figures 6A and 6B, it is possible to supply power to the desired region depending on the situation. This makes it possible to avoid affecting medical devices such as pacemakers, even if there are people with such devices.

[0034] 3. Operation and Effects of the Embodiments 3-1 Cost Control In this embodiment, a method is employed to generate a magnetic field by causing multiple power supply coils to resonate in one of multiple vibration modes, thereby enabling wireless power transmission. In principle, this method can transmit large amounts of power over a wide area. While conventional technology (Non-Patent Literature 1) requires a cavity resonator that is as large as a room, this embodiment does not require such a large-scale device, thus suppressing cost increases.

[0035] 3-2 Localization of the generated magnetic field The embodiment includes power supply coils 31-33 and an excitation coil 21, and is therefore capable of generating the vibration modes shown in Figures 4A and 4B. This vibration mode can generate a concentrated and uniform magnetic field in the region Sp1 of space Sp closer to the reference axis O. In other words, this vibration mode can generate a magnetic field of a size suitable for wireless charging in a limited location. Therefore, by placing the receiving device in region Sp1, power can be transmitted efficiently. The vibration modes shown in Figures 4A and 4B are effective when there are objects in space Sp that should not be exposed to the magnetic field. For example, if space Sp is an office, it is advisable to place desks and electrical appliances (mobile phones, computers, lighting, etc.) near the reference axis O (region Sp1), and chairs, etc., so that people are positioned away from the reference axis O (region Sp2). This prevents the human body from being exposed to the magnetic field, and even if someone has a medical device such as a pacemaker, it is possible to avoid affecting that device.

[0036] 3-3 Power transmission efficiency In this embodiment, the magnetic field direction can be changed. That is, the wireless power supply device 100 can change the direction of the magnetic field formed in space Sp by switching between the vibration modes shown in Figures 4A and 4B and the vibration modes shown in Figures 6A and 6B. As a result, the direction of the magnetic field can be controlled according to the orientation of the receiving device, thereby suppressing a decrease in power transmission efficiency caused by the orientation of the receiving device.

[0037] 4. Variations 4-1 Modification 1: A configuration with four power supply coils and one excitation coil In the embodiment, the three power supply coils 31-33 were described as being arranged radially along the radial direction of the reference axis O, but the wireless power supply device 100 is not limited to this, and may have four or more power supply coils. As shown in Figures 7-8B, in this modified example 1, the four power supply coils 31-34 are arranged radially along the radial direction of the reference axis O. Even in this configuration, the same effects as in the embodiment can be obtained.

[0038] As shown in Figures 7 to 8B, the wireless power supply device 100 further comprises a partition p4 and a power supply coil 34. Partition p4 has the same configuration as partitions p1 to p3 and is composed of, for example, a panel 14 and a frame (not shown) to which panel 14 is attached.

[0039] In this modified example 1, partitions p1 to p4 (four power supply coils 31 to 34) are arranged so as to be aligned at equal angles with respect to the reference axis O. In other words, power supply coil 31 and power supply coil 32 are arranged to form a 90-degree angle, and the angles between power supply coil 32 and power supply coil 33, between power supply coil 32 and power supply coil 33, and between power supply coil 34 and power supply coil 31 are also 90 degrees. In this embodiment, the power supply coils 31-34 are described as being arranged at equal angles (90 degrees) around the reference axis O, but the invention is not limited to this. There may be some variation in the angles formed by each power supply coil. Specifically, the angles formed by each power supply coil 31-34 may be, for example, 70, 75, 80, 85, 90, 95, 100, 105, 110, or within the range of any two of the values ​​exemplified here.

[0040] In this modified example 1, the coupling of the power supply coils 31 to 34 makes it possible to generate four vibration modes with different resonant frequencies. Specifically, it is possible to generate the vibration mode with the lowest resonant frequency (Figures 9A and 10A: resonant frequency is, for example, 1.49 MHz), the vibration mode with the second lowest resonant frequency (Figures 9B and 10B: resonant frequency is, for example, 1.61 MHz), the vibration mode with the second highest resonant frequency (Figures 9C and 10C: resonant frequency is, for example, 1.68 MHz), and the vibration mode with the highest resonant frequency (Figures 9D and 10D: resonant frequency is, for example, 1.72 MHz).

[0041] The vibration modes shown in Figures 9A and 10A are similar to the vibration modes shown in Figures 4A and 4B described in the embodiment. In other words, the direction of the current flowing through each power supply coil 31 to 34 is the same. Furthermore, in this vibration mode, a magnetic field can be concentrated in the region Sp1 of the space Sp closer to the reference axis O. This vibration mode is more effective in avoiding interference with medical devices such as pacemakers, even if there are people with such devices implanted.

[0042] The vibration modes shown in Figures 9B and 10B and those shown in Figures 9C and 10C have magnetic field distributions that differ by 90 degrees in the direction of the magnetic field. Furthermore, the vibration modes shown in Figures 9D and 10D have a magnetic field distribution that includes the weaker magnetic field regions of the vibration modes shown in Figures 9B and 10B, and the vibration modes shown in Figures 9C and 10C. For example, if you want to weaken the magnetic field in areas other than those surrounding the power supply coils 31-34, you can combine these vibration modes (selectively using them depending on the situation) to deliver power to a more limited area. In other words, with four power supply coils, the effect of avoiding interference with medical devices such as pacemakers is higher. Furthermore, with four power supply coils, the degree of freedom in changing the direction of the magnetic field increases, which effectively suppresses the decrease in power transmission efficiency caused by the orientation of the receiving device.

[0043] 4-2 Modification 2: Configuration with 4 power supply coils + 2 excitation coils As shown in Figure 11, the wireless power supply device 100 according to this modified example 2 is equipped with two excitation coils 21 and 22. Excitation coil 21 is positioned between partition p1 and partition p2, and excitation coil 22 is positioned between partition p2 and partition p3. In other words, excitation coil 21 is positioned between an adjacent pair of power supply coils 31 and 32 in the circumferential direction of the reference axis O. Excitation coil 22 is positioned between a different pair of power supply coils 32 and 33 in the circumferential direction of the reference axis O, distinct from the pair of power supply coils 31 and 32 that sandwich excitation coil 21. That is, excitation coils 21 and 22 are positioned in adjacent spaces Sp in the circumferential direction. Note that one of the excitation coils 21 and 22 is an example of a first excitation coil, and the other is an example of a second excitation coil.

[0044] In this modified example, when the power supply coils 31-34 and the excitation coils 21 and 22 are viewed from above, the excitation coil 22 is positioned approximately perpendicular or perpendicular to the excitation coil 21. Also, when the power supply coils 31-34 and the excitation coils 21 and 22 are viewed from above, the excitation coils 21 and 22 are positioned at a 45-degree angle to the power supply coils 31-34. In this modified example 2, as in modified example 1, the four vibration modes are not generated, but the excitation coils 21 and 22 can be used in the two methods described below.

[0045] 4-2-1 Selectively drive the excitation coils 21 and 22. The first method involves supplying power alternately from the high-frequency power supply 1 to the excitation coils 21 and 22. That is, when the high-frequency power supply 1 is supplying power to the excitation coil 21, it does not supply power to the excitation coil 22 (see Figures 12A and 12B). Conversely, when the high-frequency power supply 1 is supplying power to the excitation coil 22, it does not supply power to the excitation coil 21 (see Figures 12C and 12D). Here, the magnetic fields shown in Figures 12A and 12B are shifted by 90 degrees relative to the magnetic fields shown in Figures 12C and 12D. In other words, the high-frequency power supply 1 can alternately supply power to the excitation coils 21 and 22, thereby changing the direction of the magnetic field by 90 degrees. Thus, in this modified example, the magnetic field distribution can be changed (the weaker parts of the magnetic field can be changed) by selectively driving the excitation coils 21 and 22. In addition, by alternately switching the excitation coils 21 and 22 on and off in a very short time, a uniform magnetic field can be generated in the circumferential direction in the region Sp1 closer to the reference axis O.

[0046] 4-2-2 Simultaneously drive excitation coils 21 and 22. The second method involves simultaneously supplying power to excitation coils 21 and 22 from a high-frequency power supply 1. In this case, the power supplied to excitation coil 21 and the power supplied to excitation coil 22 have a predetermined phase difference (90 degrees in this modified example). This makes it possible to generate a magnetic field that rotates around the reference axis O in the region Sp1 near the reference axis O (not shown). [Explanation of symbols]

[0047] 1:High frequency power supply 2: Exciter 3: Power supply resonator 11: Panel 12: Panel 13: Panel 14: Panel 21: Excitation coil 22: Excitation coil 31: Power supply coil 32: Power supply coil 33: Power supply coil 34: Power supply coil 100: Wireless power supply device C: Center position O:Reference axis Sp1 :Area Sp2 :Area Sp: space p1: Partition p2: Partition p3: Partition p4: Partition s :Inner edge t: Outer edge

Claims

1. It comprises a high-frequency power supply, an exciter, and a power supply resonator. The exciter comprises a first excitation coil and a second excitation coil. The first excitation coil is electrically connected to the high-frequency power supply, The aforementioned power supply resonator has at least three power supply coils, The power supply coils are arranged substantially radially or radially along the radial direction of a predetermined reference axis. The aforementioned power supply coils have the same resonant frequency, and by coupling them, vibration modes with predetermined modal frequencies are generated. The first excitation coil is positioned so as to be sandwiched between an adjacent pair of the power supply coils in the circumferential direction of the reference axis. The second excitation coil is positioned in the circumferential direction of the reference axis between a pair of power supply coils different from the pair of power supply coils that sandwich the first excitation coil, and the second excitation coil is positioned substantially or perpendicular to the first excitation coil. A wireless power supply device, wherein the high-frequency power supply is configured to supply power at a frequency corresponding to the mode frequency of the vibration mode to the first excitation coil to excite the power supply resonator and cause the power supply coil to resonate in the vibration mode.

2. A wireless power supply device according to claim 1, The power supply coil is formed in a planar or smooth curved shape in this wireless power supply device.

3. A wireless power supply device according to claim 1 or claim 2, The high-frequency power supply is a wireless power supply device that supplies power to the first excitation coil such that, when each of the power supply coils is viewed from the front, the power supply coils resonate in a vibration mode in which current flows in the same direction through each of the power supply coils.

4. A wireless power supply device according to any one of claims 1 to 3, The high-frequency power supply is a wireless power supply device that changes the frequency of the power supplied to the first excitation coil so that the power supply coil resonates in multiple vibration modes in which the direction of the generated magnetic field is different.

5. A wireless power supply device according to any one of claims 1 to 4, The power supply resonator is a wireless power supply device having four power supply coils.

6. A wireless power supply device according to any one of claims 1 to 5, The aforementioned high-frequency power supply is a wireless power supply device that alternately supplies power to the first and second excitation coils.

7. A wireless power supply device according to any one of claims 1 to 5, The aforementioned high-frequency power supply simultaneously supplies power to the first and second excitation coils. A wireless power supply device in which the power supplied to the first excitation coil and the power supplied to the second excitation coil have a predetermined phase difference.

8. A wireless power supply device according to any one of claims 1 to 7, The wireless power supply device comprises a spiral coil having a triangular, parallelogram, rectangular, polygonal, circular, or combination thereof shape in plan view.

9. A wireless power supply device according to any one of claims 1 to 8, It also has at least three more partitions, A wireless power supply device in which each of the aforementioned power supply coils is provided within each of the aforementioned partitions.

10. A wireless power supply method using a video power supply, an exciter, and a power supply resonator, Equipped with a resonance step, The exciter comprises a first excitation coil and a second excitation coil. The first excitation coil is electrically connected to the high-frequency power supply, The aforementioned power supply resonator has at least three power supply coils, The power supply coils are arranged substantially radially or radially along the radial direction of a predetermined reference axis. The aforementioned power supply coils have the same resonant frequency, and by coupling them, vibration modes with predetermined modal frequencies are generated. The first excitation coil is positioned so as to be sandwiched between an adjacent pair of the power supply coils in the circumferential direction of the reference axis. The second excitation coil is positioned in the circumferential direction of the reference axis between a pair of power supply coils different from the pair of power supply coils that sandwich the first excitation coil, and the second excitation coil is positioned substantially or perpendicular to the first excitation coil. In the resonance step, the high-frequency power supply provides power to the first excitation coil at a frequency corresponding to the mode frequency of the vibration mode to excite the power supply resonator, causing the power supply coil to resonate in the vibration mode.

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