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 an increase in cost.SOLUTION: There is provided a wireless power supply device that comprises a high-frequency power supply, an exciter and a power supply resonator, wherein the exciter has a first excitation coil, which is electrically connected to the high-frequency power supply. Further, the power supply resonator has first and second power supply coils, which have the same resonance frequency, and are combined together to generate a plurality of vibration modes differing in mode frequency. Furthermore, the high-frequency power supply supplies electric power of frequency corresponding to a mode frequency of one of the plurality of vibration modes to the first excitation coil to excite the power supply resonator, thereby causing the first and second power supply coils to resonate in one of the plurality of vibration modes.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 technology]

[0002] With the spread of the Internet of Things (IoT), various devices are being connected to the Internet. These devices require periodic charging and battery replacement, and the problem of the cost of power supply has become apparent. In recent years, therefore, wireless power transfer (WPT) to devices located anywhere in a three-dimensional space has been attracting attention. WPT includes a microwave power transmission method, which is capable of supplying power through a three-dimensional space, but has a problem that it is very inefficient and cannot supply large amounts of power. In response to this, a method has been proposed in which a cavity resonator, which is often used in microwave filters, etc., is expanded to the size of a room, and large amounts of power can be transmitted over a wide area within the room (within the cavity resonator) (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] T. Sasatani et el "Multimode quasistatic cavity resonators for wireless power transfer," IEEE Antennas and wireless propagation letters, vol. 16, pp. 2746-2749, 2017 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Non-Patent Document 1 requires that the size of a cavity resonator made of metal be increased and that the space in which wireless power supply is to be realized be surrounded by the cavity resonator, which poses a problem in terms of cost.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a wireless power supply device and a wireless power supply method that can suppress an increase in costs. [Means for solving the problem]

[0006] According to the present invention, there is provided a wireless power supply device comprising: a high-frequency power supply; an exciter; and a power supply resonator, wherein the exciter has a first excitation coil, and the first excitation coil is electrically connected to the high-frequency power supply; the power supply resonator has first and second power supply coils, and the first and second power supply coils have the same resonant frequency and are coupled to generate a plurality of vibration modes having different mode frequencies; and the high-frequency power supply is configured to supply power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first excitation coil to excite the power supply resonator and cause the first and second power supply coils to resonate in one of the plurality of vibration modes.

[0007] According to the present invention, a method for wireless power supply is provided by generating a magnetic field by resonating first and second power supply coils in one of a plurality of vibration modes, and a cavity resonator enlarged to the size of a room is not required. It is sufficient to provide the coils in the target space, thereby suppressing increases in costs.

[0008] Various embodiments of the present invention will be described below. The embodiments described below can be combined with each other. Preferably, the power supply resonator further includes a third and a fourth power supply coil, one of the first to fourth power supply coils is arranged in front of the first excitation coil, the first to fourth power supply coils have the same resonant frequency, and a plurality of vibration modes having different mode frequencies are generated by coupling the first to fourth power supply coils, and the high-frequency power source supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first excitation coil to excite the power supply resonator, thereby causing the first to fourth power supply coils to resonate in one of the plurality of vibration modes. Preferably, a wireless power supply device is provided in which two of the plurality of vibration modes generate magnetic fields in different directions, and the distribution of the magnetic field in a horizontal plane passing through the power supply resonator is more uniform than that of the remaining vibration modes of the plurality of vibration modes. Preferably, the exciter further has a second excitation coil, the second excitation coil being electrically connected to the high-frequency power supply; the power supply resonator further has third and fourth power supply coils, the first to fourth power supply coils have the same resonant frequency and are coupled to generate a plurality of vibration modes having different mode frequencies; the high-frequency power supply supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to at least one of the first and second excitation coils to excite the power supply resonator and cause the first to fourth power supply coils to resonate in one of the plurality of vibration modes. Preferably, in the wireless power supply device, the first to fourth power supply coils are arranged so as to form an enclosure. Preferably, there is provided a wireless power supply device in which the first and third power supply coils are arranged to face each other, the second and fourth power supply coils are arranged to face each other, the first power supply coil is arranged to be orthogonal or approximately orthogonal to the second and fourth power supply coils, and the third power supply coil is arranged to be orthogonal or approximately orthogonal to the second and fourth power supply coils. Preferably, the wireless power supply device is provided in which, when a portion where the first and fourth power supply coils intersect is defined as a first corner region, the first excitation coil is disposed in the first corner region, and, when a portion where the third and fourth power supply coils intersect is defined as a second corner region, the second excitation coil is disposed in the second corner region. Preferably, in the wireless power supply device, the first to fourth power supply coils are configured as spiral coils. Preferably, in the wireless power supply device, the first to fourth power supply coils have a rectangular shape in a plan view. Preferably, in the wireless power supply device, the power supply resonator has a dielectric housing having first to fourth side surface portions, and the first to fourth power supply coils are provided on the first to fourth side surface portions, respectively. Preferably, in the wireless power supply device, the first to fourth power supply coils and the first to fourth side surface portions have a rectangular shape in a plan view, the first to fourth power supply coils are formed to be approximately smaller than the first to fourth side surface portions, and outer edges of the first to fourth power supply coils are arranged approximately parallel to and close to each side of the first to fourth side surface portions. Preferably, a wireless power supply device is provided in which the high-frequency power source selectively supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first and second excitation coils to excite the power supply resonator. Preferably, a wireless power supply device is provided in which the high-frequency power supply simultaneously supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first and second excitation coils to excite the power supply resonator. According to another aspect of an embodiment of the present invention, there is provided a wireless power supply method using a high-frequency power supply, an exciter, and a power supply resonator, comprising a resonance step, the exciter has a first excitation coil, and the first excitation coil is electrically connected to the high-frequency power supply, the power supply resonator has first to fourth power supply coils, the first to fourth power supply coils have the same resonance frequency, and a plurality of vibration modes having different mode frequencies are generated by coupling the first to fourth power supply coils, and one of the first to fourth power supply coils is disposed in front of the first excitation coil, and in the resonance step, the high-frequency power supply supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first excitation coil to excite the power supply resonator, and causes the first to fourth power supply coils to resonate in one of the plurality of vibration modes. According to another aspect of an embodiment of the present invention, there is provided a wireless power supply method using a high-frequency power supply, an exciter, and a power supply resonator, comprising a resonance step, the exciter has first and second excitation coils, the first and second excitation coils being electrically connected to the high-frequency power supply, the power supply resonator has first to fourth power supply coils, the first to fourth power supply coils have the same resonance frequency, and a plurality of vibration modes having different mode frequencies are generated by coupling the first to fourth power supply coils, and in the resonance step, the high-frequency power supply supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to at least one of the first and second excitation coils to excite the power supply resonator, and causes the first to fourth power supply coils to resonate in one of the plurality of vibration modes. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the overall configuration of a wireless power supply device 100 according to an embodiment. [Diagram 2] FIG. 2 is a perspective view of the exciter 2 and the power supply resonator 3. As shown in FIG. [Diagram 3] FIG. 3 is a top view of the exciter 2 and the power supply resonator 3. As shown in FIG. [Figure 4] Fig. 4A is a perspective view showing a state in which the dielectric housing is removed from the exciter 2 and the power-feeding resonator 3 shown in Fig. 2. Fig. 4B is a perspective view of the power-feeding coil 31 and the power-feeding coil 33. [Diagram 5] FIG. 5 is a front view of the power supply coils (power supply coils 31 to 34). [Figure 6] Fig. 6 is a distribution diagram showing the strength and direction of the magnetic field in this vibration mode, which is the result of calculations by an electromagnetic field simulator. In Fig. 6, the direction of the arrow indicates the direction of the magnetic field at each location, and the darker the color of the arrow, the stronger the magnetic field. Fig. 6 shows the distribution of the magnetic field in the horizontal plane at the height position Z=0 shown in Fig. 7. In Fig. 6, the symbol Sg1 indicates the direction of the current passing through the coil portion X1 shown in Fig. 5, and the symbol Sg2 indicates the direction of the current passing through the coil portion X2 shown in Fig. 5. [Figure 7] Fig. 7 is a distribution diagram showing the magnetic field strength in the vibration mode of Fig. 6, which is a calculation result of an electromagnetic field simulator. Fig. 7 shows the distribution diagram for each horizontal plane at each height position (Z=h1, Z=h2, Z=h3, Z=h4, Z=h5). The horizontal plane at Z=h1 passes through the center of the power feed coil, and the horizontal plane at Z=h5 passes through the top of the power feed coil. The horizontal planes at Z=h2, Z=h3, and Z=h4 are equally spaced between the horizontal plane at Z=h1 and the horizontal plane at Z=h5. [Figure 8] Fig. 8 is a distribution diagram showing the strength and direction of the magnetic field in this vibration mode, which is the result of calculations using an electromagnetic field simulator. In Fig. 8, the direction of the arrow indicates the direction of the magnetic field at each location, and the darker the color of the arrow, the stronger the magnetic field. Fig. 8 shows the distribution of the magnetic field on the horizontal plane at the height position Z=0 shown in Fig. 9. [Figure 9] Fig. 9 is a distribution diagram showing the results of calculations by an electromagnetic field simulator, illustrating the magnetic field strength in the vibration mode of Fig. 8. Fig. 9 shows the distribution diagram for each horizontal plane at each height position (Z=h1, Z=h2, Z=h3, Z=h4, Z=h5). [Figure 10]Figure 10 is a distribution diagram showing the strength and direction of the magnetic field in this vibration mode, which is the result of calculations using an electromagnetic field simulator. In Figure 10, the direction of the arrow indicates the direction of the magnetic field at each location, and the darker the color of the arrow, the stronger the magnetic field. The height position of the distribution diagram shown in Figure 10 is the same as the height position shown in Figure 7. [Figure 11] Fig. 11 is a distribution diagram showing the magnetic field strength and direction in this vibration mode, which is the result of calculations using an electromagnetic field simulator. In Fig. 11, the direction of the arrow indicates the magnetic field direction at each location, and the darker the arrow, the stronger the magnetic field. The height position of the distribution diagram shown in Fig. 11 is the same as the height position shown in Fig. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Various characteristic features shown in the following embodiment can be combined with each other. Also, each characteristic feature can be an invention independently.

[0011] 1. Embodiment 1-1 Overall configuration As shown in FIG. 1, the wireless power supply device 100 according to the embodiment includes a high-frequency power source 1, an exciter 2, and a power supply resonator 3. The wireless power supply device 100 employs a magnetic field coupling method that can charge various devices (power receiving devices) that are targets of charging across a three-dimensional space. The various devices that are targets of charging are suitable for power supply to, for example, electrical appliances (mobile phones, personal computers, lighting, etc.) and power tools in factories. In addition, the embodiment can be applied to non-contact power supply to various sensors that are indispensable in an IoT society and non-contact power supply to in-body medical devices such as capsule endoscopes. In addition, by arranging the power supply resonator 3 on a partition (partition plate) for dividing the space in an office, it is possible to realize non-contact power supply to electrical appliances (for example, personal computers, etc.) arranged in the office.

[0012] The wireless power supply device 100 is capable of coupling (electromagnetically coupling) multiple power supply coils (power supply coils 31 to 34 described below), and by coupling the multiple power supply coils, multiple vibration modes having different mode frequencies are generated in the multiple power supply coils.

[0013] Specifically, the wireless power supply device 100 can generate two vibration modes as shown in Figs. 10 and 11 by using the excitation coil 21, and can generate two vibration modes as shown in Figs. 10 and 11 by using the excitation coil 22. Here, since the positions of the excitation coil 21 and the excitation coil 22 are shifted from each other, when the vibration mode corresponding to Fig. 10 is generated using the excitation coil 21, the magnetic field has a direction as shown in Fig. 6. That is, the generated vibration mode is the same when the excitation coil 21 is used to generate the vibration mode corresponding to Fig. 10 and when the excitation coil 22 is used to generate the vibration mode corresponding to Fig. 10, but the magnetic field direction is different because the positions of the excitation coils are different (see the direction of the excitation coil 21 shown in Fig. 6 and the direction of the excitation coil 22 shown in Fig. 10). Depending on the orientation of various devices to be charged, the magnetic flux does not properly pass through the coils in the devices, which reduces the transmission efficiency. Therefore, in the embodiment, by using excitation coil 21 and excitation coil 22 appropriately, the direction of the magnetic field can be changed without changing the frequency used, and it is possible to prevent the transmission efficiency from decreasing depending on the orientation of various devices to be charged.

[0014] Moreover, the wireless power supply device 100 can generate four vibration modes as shown in Fig. 6, Fig. 8, Fig. 10, and Fig. 11 by driving the excitation coil 23. One of the power supply coils is arranged to face the front of the excitation coil 23. That is, the excitation coils 21 and 22 are arranged at the corners of the power supply resonator 3 to form a predetermined angle (45 degrees in the embodiment) with respect to the power supply coils 31 and 34, but the excitation coil 23 is arranged parallel to the power supply coil 32, and the power supply coil 32 is arranged in front of the excitation coil 23. When the excitation coil 23 is driven, the number of vibration modes that can be generated is greater than when the excitation coils 21 and 22 are driven. The configuration of the wireless power supply device 100 according to the embodiment will be specifically described below.

[0015] 1-2 High frequency power supply 1 The high frequency power supply 1 is configured to excite the power supply resonator 3 via the exciter 2. That is, the high frequency power supply 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 supply 1 is connected to the excitation coils 21 to 23 of the exciter 2, which will be described later. In the embodiment, the high frequency power supply 1 is capable of selectively supplying AC power to the excitation coils 21 to 23 of the exciter 2. In other words, when the high frequency power supply 1 supplies AC power to the excitation coil 21, it does not supply AC power to the excitation coils 22 and 23, when it supplies AC power to the excitation coil 22, it does not supply AC power to the excitation coils 21 and 23, and when it supplies AC power to the excitation coil 23, it does not supply AC power to the excitation coils 21 and 22. The high frequency power supply 1 is controlled by a control device (not shown).

[0016] 1-3 Exciter 2 As shown in Figs. 2 to 4A, the exciter 2 includes excitation coils 21 to 23. The excitation coils 21 to 23 are electrically connected to a high-frequency power source 1 and configured to receive high-frequency AC power. The excitation coils 21 to 23 have the same configuration (shape). The shape of the excitation coils 21 to 23 is not particularly limited, but it is preferable that the shape and size of the excitation coils 21 to 23 are such that electromagnetic field coupling can be easily formed with the power supply coils 31 to 34 described below. In the embodiment, the shape of the excitation coils 21 to 23 is circular. 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. Also, the excitation coil 23 is an example of a first excitation coil.

[0017] The exciting coil 21 is disposed so as to excite the power feeding coils 31 to 34. That is, when the high-frequency power supply 1 supplies electric power having a frequency corresponding to the mode frequency of one of the multiple vibration modes to the exciting coil 21, the power feeding coils 31 to 34 are excited. The excitation coil 22 is also disposed so as to excite the power feeding coils 31 to 34. That is, when the high-frequency power supply 1 supplies power of a frequency corresponding to the mode frequency of one of the multiple vibration modes to the excitation coil 22, the power feeding coils 31 to 34 are excited. Furthermore, the excitation coil 23 is also arranged to excite the power feeding coils 31 to 34. That is, when the high-frequency power supply 1 supplies power of a frequency corresponding to the mode frequency of one of the multiple vibration modes to the excitation coil 23, the power feeding coils 31 to 34 are excited.

[0018] The excitation coil 22 is arranged so that the direction of the magnetic field in the vibration mode when the power supply resonator 3 is excited by the excitation coil 22 is different from the direction of the magnetic field in the vibration mode when the power supply resonator 3 is excited by the excitation coil 21. Specifically, the arrangement of the excitation coils 21 and 22 can be defined using first and second corner regions Rg1 and Rg2. The first corner region Rg1 is a region corresponding to a portion where the power supply coil 31 and the power supply coil 34 intersect. The second corner region Rg2 is a region corresponding to a portion where the power supply coil 33 and the power supply coil 34 intersect. In the embodiment, the excitation coil 21 is arranged in the first corner region Rg1, and the excitation coil 22 is arranged in the second corner region Rg2.

[0019] 1-4 Power supply resonator 3 2 to 4, the power supply resonator 3 includes power supply coils 31 to 34 and a dielectric housing 35. The power supply coils 31 to 34 are examples of first to fourth power supply coils.

[0020] 1-4-1 Power coil 4A, the power supply coils 31 to 34 have the same configuration (shape). Therefore, the power supply coils 31 to 34 have the same resonant frequency. Furthermore, the wireless power supply device 100 is capable of coupling (electromagnetic field coupling) the power supply coils 31 to 34, and the coupling of the power supply coils 31 to 34 generates four vibration modes having different resonant frequencies in the power supply coils 31 to 34.

[0021] As shown in Fig. 5, each of the power supply coils 31 to 34 has a rectangular or substantially rectangular shape (substantially square in the embodiment) in a plan view. Each of the power supply coils 31 to 34 is configured as a spiral coil. That is, each of the power supply coils 31 to 34 is configured as a coil formed by winding a conductor in a spiral shape in a plan view. As shown in Figs. 4A to 5, each of the power supply coils 31 to 34 is a non-annular coil having an inner end s and an outer end t. The number of turns of each of the power supply coils 31 to 34 is not particularly limited.

[0022] As shown in Fig. 4, the power supply coils 31 to 34 are arranged to form an enclosure. This allows the wireless power supply device 100 to suppress unevenness in the magnetic field formed in the space Sp inside the power supply coils 31 to 34, and allows effective power supply regardless of the position of the device to be charged placed in the space Sp. The wireless power supply device 100 is configured to be able to execute a plurality of vibration modes, and among them, the vibration mode shown in Fig. 6 and the vibration mode shown in Fig. 10 are particularly effective in suppressing unevenness in the magnetic field formed in the space Sp as described above.

[0023] 3, the power supply coil 31 and the power supply coil 33 are disposed to face each other in a first direction Dr1. The power supply coil 32 and the power supply coil 34 are disposed to face each other in a second direction Dr2. In the embodiment, the first direction Dr1 and the second direction Dr2 are orthogonal or substantially orthogonal to each other, and the first direction Dr1 and the second direction Dr2 are parallel to a horizontal plane.

[0024] As shown in FIG. 3, the power supply coil 31 is disposed so as to be orthogonal or substantially orthogonal to the power supply coils 32 and 34. Specifically, an imaginary plane extending from the plane on which the power supply coil 31 is disposed intersects with an imaginary plane extending from the plane on which the power supply coils 32 and 34 are disposed so as to be orthogonal or substantially orthogonal to the power supply coils 32 and 34. Note that a portion where an imaginary plane extending from the plane on which the power supply coil 31 is disposed intersects with an imaginary plane extending from the plane on which the power supply coil 34 is disposed corresponds to the above-mentioned first corner region Rg1. Similarly, the power supply coil 33 is disposed so as to be orthogonal or substantially orthogonal to the power supply coils 32 and 34. Specifically, an imaginary plane extending from the plane on which the power supply coil 33 is disposed intersects with an imaginary plane extending from the plane on which the power supply coil 32 and 34 are disposed so as to be orthogonal or substantially orthogonal to the power supply coils 32 and 34. Note that a portion where an imaginary plane extending from the plane on which the power supply coil 33 is disposed intersects with an imaginary plane extending from the plane on which the power supply coil 32 is disposed corresponds to the above-mentioned second corner region Rg2.

[0025] 1-4-2 Dielectric housing part 35 As shown in FIG. 2, the dielectric housing 35 has side sections 35a to 35d. The power supply coils 31 to 34 are provided on the side sections 35a to 35d, respectively. Each of the side sections 35a to 35d functions as a dielectric. The power supply coils 31 to 34 cannot be fixed to a metal body, so they are attached to the side sections 35a to 35d as dielectrics. The dielectric housing 35 also functions to maintain the shape of the power supply coils 31 to 34. That is, when the diameter of the power supply coils 31 to 34 is small, the rigidity of the power supply coils 31 to 34 is low, and therefore, without the dielectric housing 35, the power supply coils 31 to 34 may bend under their own weight. For this reason, by providing the dielectric housing 35 to the power supply resonator 3, the shape of the power supply coils 31 to 34 can be maintained.

[0026] The side surface portions 35a to 35d have a rectangular shape in a plan view. The power supply coils 31 to 34 are formed to be substantially smaller than the side surface portions 35a to 35d. The outer edge portion 3t (see FIG. 5) of the power supply coil 31 is disposed parallel or substantially parallel to each side 35t (see FIG. 2) of the side surface portion 35a. The outer edge portion 3t of the power supply coil 31 is disposed close to each side 35t of the side surface portion 35a. The power supply coils 32 to 34 have a similar configuration.

[0027] 1-5 Other configuration: Power receiving device The power receiving device (various devices to be charged) includes a coil (resonator) (not shown). When the power receiving device is placed in the space Sp, the coil of the power receiving device is coupled with the magnetic field formed by the power feeding coils 31 to 34 of the power feeding resonator 3. As a result, the power of the high frequency power source 1 is transmitted to the power receiving device via the excitation coil and the power feeding coil.

[0028] 2. Description of vibration modes The wireless power supply device 100 is configured to be able to execute a resonance step. In the resonance step, the high frequency power source 1 supplies power of a frequency corresponding to a mode frequency of one of the plurality of vibration modes to the excitation coils 21 and 22 to excite the power supply resonator 3, and causes the power supply coils 31 to 34 to resonate in one of the plurality of vibration modes. The multiple vibration modes have different mode frequencies.

[0029] 2-1 Relationship between the driving excitation coil and the vibration modes that can be generated The types of vibration modes that can be generated vary depending on the excitation coils to be driven. In other words, the types of vibration modes that can be generated vary depending on the arrangement of the excitation coils to be driven. Specifically, the types of vibration modes that can be generated vary depending on the arrangement of the excitation coils to be driven. Specifically, the types of vibration modes that can be generated vary depending on the arrangement of the excitation coils to be driven.

[0030] (1) When the excitation coil 23 is driven, the four vibration modes shown in FIG. 6, FIG. 8, FIG. 10 and FIG. 11 can be generated. (2) When the excitation coil 21 or the excitation coil 22 is driven, two vibration modes shown in Fig. 10 and Fig. 11 can be generated. (However, when the excitation coil 21 is driven to generate the vibration mode corresponding to Fig. 10, the direction of the magnetic field is the direction shown in Fig. 6.) The characteristics of each vibration mode shown in Figs. 6, 8, 10 and 11 will be described below.

[0031] 2-2 About each vibration mode 2-2-1 Mode that generates a magnetic field in an oblique direction (Figure 6) In the vibration mode shown in Fig. 6, the direction of the magnetic field in the center of the space Sp and its vicinity forms an obtuse angle with respect to the X-axis. In the vibration mode shown in Fig. 6, the magnetic fields of the four power supply coils are synthesized so as to reinforce each other, so that the magnetic field distribution in the horizontal plane of this vibration mode has a high magnetic field strength at the corners and also in the entire region inside the four corners, as shown in Figs. 6 and 7. This tendency is also the same when the height direction of the horizontal plane is changed. From these facts, it can be seen that the vibration mode shown in Fig. 6 is a mode in which the magnetic field distribution is highly uniform three-dimensionally and the magnetic field strength itself is generally high.

[0032] 2-2-2 Mode in which a magnetic field is generated concentratedly at the four corners and their vicinity (Figure 8) In the vibration mode shown in Fig. 8, the magnetic field strength is low in the center and high in the surrounding area of ​​the center, as shown in Fig. 8 and Fig. 9. This vibration mode is effective when it is desired to transmit power only to the surrounding area.

[0033] 2-2-3 Mode that generates a magnetic field in an oblique direction (Figure 10) In the vibration mode shown in FIG. 10, the direction of the magnetic field in the center of the space Sp and its vicinity forms an acute angle with respect to the X-axis. In the vibration mode shown in FIG. 10, like the vibration mode shown in FIG. 6, the magnetic field strength is particularly high at the corners, and the magnetic field strength is also distributed in the entire inner region of the four corners. On the other hand, the magnetic field direction of the vibration mode shown in FIG. 10 is characterized in that it is shifted by 90 degrees from the magnetic field direction of the vibration mode shown in FIG. 6 in the horizontal plane. For this reason, the vibration mode shown in FIG. 10 has a high uniformity of magnetic field distribution three-dimensionally and the magnetic field strength itself is generally high, and the magnetic field direction is different from that of the vibration mode shown in FIG. 6. Therefore, by selectively using the vibration mode shown in FIG. 6 and the vibration mode shown in FIG. 10, magnetic fields of different directions can be generated in the space Sp.

[0034] 2-2-4 Mode in which magnetic field is concentrated at the four corners (Fig. 11) In the vibration mode shown in Fig. 11, the magnetic field strength is high in the localized areas of the corners, but low in other areas (the center and the area between adjacent corners). In other words, this vibration mode is capable of transmitting power to a more limited area than the vibration mode shown in Fig. 8. 11 shows the distribution of the magnetic field in the horizontal plane region at the center in the height direction of the power feeding coils 31 to 34. Here, in this vibration mode, the distribution of the magnetic field in the horizontal plane region at the top and bottom in the height direction of the power feeding coils 31 to 34 is more uniform than the distribution of the magnetic field in the horizontal plane region at the center in the height direction of the power feeding coils 31 to 34 (FIG. 11). Therefore, in this vibration mode, a magnetic field can be generated in a limited area such as the floor side or ceiling side of the space Sp, and power can be transmitted in a limited manner to the area.

[0035] 2-3 How to use the vibration mode 2-3-1 Controlling the direction of the magnetic field Part 1 Here, a description will be given of the case where the exciting coil 23 is driven. When the exciting coil 23 is driven, four vibration modes shown in Figs. The vibration mode shown in FIG. 6 and the vibration mode shown in FIG. 10 are modes with high uniformity in the distribution of the magnetic field three-dimensionally. Therefore, they are effective when transmitting power to a plurality of devices arranged in various places in the space Sp. Depending on the orientation of the devices (the orientation of the resonance coil built into the devices), the power transmission efficiency may decrease when one of the vibration modes shown in FIG. 6 and the vibration mode shown in FIG. 10 is being executed. In such a case, the decrease in the power transmission efficiency can be suppressed by switching the vibration mode from one of the vibration modes shown in FIG. 6 and the vibration mode shown in FIG. 10 to the other mode.

[0036] 2-3-2 Controlling the direction of the magnetic field Part 2 Here, a description will be given of the case where the exciting coils 21 and 22 are driven. When the exciting coils 21 and 22 are driven, two vibration modes shown in Figs. As described above, the vibration mode in FIG. 6 and the vibration mode in FIG. 10 have different magnetic field directions, but the wireless power supply device 100 can change the magnetic field direction in addition to changing the vibration mode. That is, the magnetic field direction can be changed by switching the excitation coil driven by the high frequency power supply 1. For example, when the vibration mode corresponding to FIG. 10 is generated using the excitation coil 21, a magnetic field as shown in FIG. 6 is generated, but when the vibration mode corresponding to FIG. 10 is generated using the excitation coil 22, a magnetic field as shown in FIG. 10 is generated. That is, the same vibration mode is generated, but the magnetic field direction is different. The mode frequency of the vibration mode corresponding to FIG. 10 generated using the excitation coil 21 is the same as the mode frequency of the vibration mode corresponding to FIG. 10 generated using the excitation coil 22, so that it is effective in avoiding the configuration of the resonance coil becoming complicated in the power receiving device.

[0037] 2-3-3 Limiting the locations where strong magnetic fields are formed In addition, the vibration mode of Fig. 8 and the vibration mode of Fig. 11 have a lower magnetic field strength and are not as uniform as the vibration mode of Fig. 6 and the vibration mode of Fig. 10. However, as described above, the vibration mode of Fig. 8 and the vibration mode of Fig. 11 can generate a magnetic field in a limited location, in other words, can limit the location where a strong magnetic field is formed, and are therefore effective, for example, when a device that should not be exposed to a strong magnetic field is present in the space Sp.

[0038] 3. Functions and Effects of the Embodiments 3-1 Cost Reduction In the embodiment, a method is adopted in which a magnetic field is generated by resonating a plurality of power supply coils in one of a plurality of vibration modes to supply power wirelessly, and in principle, a large amount of power can be transmitted over a wide range. In the conventional technology (Non-Patent Document 1), a cavity resonator enlarged to the size of a room is required, whereas in the embodiment, such a large-scale device is not required, and therefore an increase in costs can be suppressed.

[0039] From the viewpoint of suppressing the decrease in power transmission efficiency, it is important to be able to change the direction of the generated magnetic field. On the other hand, when the direction of the magnetic field is changed, if the frequency (mode frequency) of the magnetic field is changed at the same time, the device on the power receiving side needs to respond to the change in the frequency of the magnetic field. On the other hand, in this embodiment, for example, the mode frequency to be used is fixed, and the direction of the magnetic field can be changed by switching the excitation coil to be driven. That is, in the example of this embodiment, the direction of the magnetic field when the vibration mode corresponding to FIG. 10 is generated can be changed by switching the excitation coil to be driven between the excitation coil 21 and the excitation coil 22. This makes it possible to avoid the complication of the configuration of the device on the power receiving side, and to suppress the cost of the entire system.

[0040] 3-2 Magnetic field uniformity In this embodiment, since the power supply coils 31 to 34 and the excitation coil 23 are provided, it is possible to generate the vibration modes in FIG. 6 and FIG. 10 in particular. These vibration modes have a high uniformity in the distribution of the magnetic field. Therefore, no matter where the power receiving device is placed in the space Sp, efficient power transmission is possible. Note that in the wireless power supply using a cavity resonator in the prior art (Non-Patent Document 1), unless two resonance modes are combined, a spatially uniform magnetic field distribution cannot be formed, and the operation and configuration become complicated. In this embodiment, it is possible to avoid such complication.

[0041] Note that a decrease in magnetic field strength in spatial corner regions can be more easily suppressed when the power supply coils 31 to 34 have a rectangular shape in plan view rather than a circular shape. Therefore, by making the power supply coils 31 to 34 have a rectangular shape in plan view as in the embodiment, it is possible to more effectively improve the uniformity of the magnetic field distribution.

[0042] 3-3 Power transmission efficiency In the embodiment, the direction of the magnetic field is configured to be changeable. That is, when the wireless power supply device 100 uses the excitation coil 23, the direction of the magnetic field formed in the space Sp can be changed by switching between the vibration mode in FIG. 6 and the vibration mode in FIG. Furthermore, when the wireless power supply device 100 uses the excitation coils 21 and 22, the direction of the magnetic field formed in the space Sp can be changed by switching the coil to be driven between the excitation coil 21 and the excitation coil 22. This makes it possible to control the direction of the magnetic field in accordance with the orientation of the power receiving device, thereby making it possible to suppress a decrease in power transmission efficiency caused by the orientation of the power receiving device.

[0043] 3-4 Selectivity of magnetic field formation region In the embodiment, in addition to the vibration mode of FIG. 6 and the vibration mode of FIG. 10, the vibration mode of FIG. 8 and the vibration mode of FIG. 11 can be generated. Compared with the vibration mode of FIG. 6 and the vibration mode of FIG. 10, the vibration mode of FIG. 8 and the vibration mode of FIG. 11 can generate a magnetic field in a limited location, and are therefore effective when there is an object in the space Sp that should not be exposed to the magnetic field. For example, when the space Sp is an office, the center of the office can be used as a living space, and the corners of the office can be used as spaces in which devices on the power receiving side, such as servers, are placed. As a result, the human body in the center of the office is not exposed to the magnetic field, and even if a person wears a medical device such as a pacemaker, it is possible to avoid affecting the device.

[0044] 4. Other embodiments 4-1 Configuration with 4 feeding coils and 1 excitation coil In the embodiment, an example has been described in which there are four power supply coils and three excitation coils, but the present invention is not limited to this example. There may be only one excitation coil. For example, the wireless power supply device 100 may be provided with only the excitation coil 23. Even in this example, the direction of the magnetic field can be changed by switching between the vibration mode of FIG. 6 and the vibration mode of FIG. 10.

[0045] 4-2 Configuration with 4 feeding coils and 2 excitation coils The number of excitation coils may be two. For example, the wireless power supply device 100 may be configured to include only the excitation coils 21 and 22. Even in this configuration, the direction of the magnetic field can be changed by switching the excitation coil to be driven between the excitation coil 21 and the excitation coil 22.

[0046] 4-3 Configuration with two power supply coils and one excitation coil Alternatively, there may be two power supply coils and one excitation coil. For example, there may be a configuration including power supply coils 31, 34 and excitation coil 21. In this configuration, two vibration modes are generated, and the direction of the magnetic field can be changed by switching between the two vibration modes.

[0047] 4-4 Power supply methods, etc. There is no limit to the number of excitation coils, and the wireless power feeder 100 may have three as in the embodiment, or may have four or more. In this case, these excitation coils can be arranged in the circumferential direction of the power feed coil. In addition, power of the same mode frequency may be supplied to these excitation coils simultaneously or selectively, and power of different mode frequencies may be supplied to these excitation coils simultaneously or selectively. For example, by selectively supplying, it is possible to change the direction of the magnetic field without changing the frequency of the power supplied from the high frequency power supply 1. In addition, by simultaneously supplying, the magnetic fields of the modes corresponding to the respective excitation coils are synthesized, so that the direction of the magnetic field when supplied simultaneously deviates from the direction of the magnetic field when one excitation coil is driven, and the effect of more finely adjusting the direction of the magnetic field can be expected. [Explanation of symbols]

[0048] 100: Wireless power supply device 1:High frequency power supply 2: Exciter 21: Excitation coil 22: Excitation coil 3: Power supply resonator 31: Power supply coil 32: Power supply coil 33: Power supply coil 34: Power supply coil 3t: Outer edge 35: Dielectric housing part 35a: Side part 35b: Side part 35c: Side part 35d: Side part 35t: side Dr1: 1st direction Dr2: 2nd direction Rg1: 1st corner area Rg2: 2nd corner area Sp: space

Claims

1. The device includes a high frequency power source, an exciter, and a power supply resonator. The exciter has a first excitation coil; The first excitation coil is electrically connected to the high frequency power source, the power supply resonator has first, second, third and fourth power supply coils; any one of the first to fourth power supply coils is disposed in front of the first excitation coil; the first to fourth power supply coils have the same resonant frequency, and a plurality of vibration modes having different mode frequencies are generated by coupling the first to fourth power supply coils; the high frequency power supply is configured to supply power having a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first excitation coil to excite the power supply resonator and to cause the first to fourth power supply coils to resonate in the one of the plurality of vibration modes; A wireless power supply device in which two of the multiple vibration modes generate magnetic fields in different directions, and the distribution of the magnetic field in a horizontal plane passing through the power supply resonator is more uniform than that of the remaining vibration modes among the multiple vibration modes.

2. The device includes a high frequency power source, an exciter, and a power supply resonator. The exciter includes a first excitation coil and a second excitation coil, the first excitation coil and the second excitation coil are electrically connected to the high frequency power source, the power supply resonator has first, second, third and fourth power supply coils; the first to fourth power supply coils have the same resonant frequency, and a plurality of vibration modes having different mode frequencies are generated by coupling the first to fourth power supply coils; the high-frequency power supply is configured to supply power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to at least one of the first and second excitation coils to excite the power supply resonator and cause the first to fourth power supply coils to resonate in one of the plurality of vibration modes.

3. The wireless power supply device according to claim 1 or 2, The first to fourth power supply coils are arranged to form an enclosure.

4. The wireless power supply device according to claim 3, the first and third power supply coils are arranged to face each other, and the second and fourth power supply coils are arranged to face each other, the first power supply coil is arranged so as to be orthogonal or approximately orthogonal to the second and fourth power supply coils, and the third power supply coil is arranged so as to be orthogonal or approximately orthogonal to the second and fourth power supply coils.

5. A wireless power supply device according to claim 4 which recites claim 3 which recites claim 2, When a portion where the first and fourth power supply coils intersect is defined as a first corner region, the first excitation coil is disposed in the first corner region, the second excitation coil is disposed in a second corner region where the third and fourth power supply coils intersect.

6. The wireless power supply device according to any one of claims 1 to 5, The wireless power supply device, wherein the first to fourth power supply coils are spiral coils.

7. The wireless power supply device according to any one of claims 1 to 6, The wireless power supply device, wherein the first to fourth power supply coils have a rectangular shape in a plan view.

8. The wireless power supply device according to any one of claims 1 to 7, the power supply resonator has a dielectric housing having first to fourth side surfaces, The first to fourth power supply coils are provided on the first to fourth side surface portions, respectively.

9. The wireless power supply device according to claim 8, the first to fourth power supply coils and the first to fourth side surface portions have a rectangular shape in a plan view, the first to fourth power supply coils are formed to be substantially smaller than the first to fourth side surface portions, The wireless power supply device, wherein outer edge portions of the first to fourth power supply coils are arranged substantially parallel to and adjacent to each side of the first to fourth side surface portions.

10. The wireless power supply device according to claim 2, The wireless power supply device, wherein the high-frequency power supply selectively supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first and second excitation coils to excite the power supply resonator.

11. The wireless power supply device according to claim 2, The wireless power supply device, wherein the high-frequency power supply simultaneously supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first and second excitation coils to excite the power supply resonator.

12. A wireless power supply method using a high-frequency power supply, an exciter, and a power supply resonator, comprising: With a resonant step, The exciter has a first excitation coil; The first excitation coil is electrically connected to the high frequency power source, the power supply resonator has first to fourth power supply coils, the first to fourth power supply coils have the same resonant frequency, and a plurality of vibration modes having different mode frequencies are generated by coupling the first to fourth power supply coils; any one of the first to fourth power supply coils is disposed in front of the first excitation coil; In the resonating step, the high frequency power supply supplies power having a frequency corresponding to the mode frequency of one of the plurality of vibration modes to the first excitation coil to excite the power supply resonator, and causes the first to fourth power supply coils to resonate in one of the plurality of vibration modes; A method in which two of the plurality of vibration modes generate magnetic fields in different directions, and the distribution of the magnetic field in a horizontal plane passing through the power supply resonator is uniform compared to the remaining vibration modes of the plurality of vibration modes.

13. A wireless power supply method using a high-frequency power supply, an exciter, and a power supply resonator, comprising: With a resonant step, the exciter has first and second excitation coils; the first and second excitation coils are electrically connected to the high frequency power source; the power supply resonator has first to fourth power supply coils, the first to fourth power supply coils have the same resonant frequency, and a plurality of vibration modes having different mode frequencies are generated by coupling the first to fourth power supply coils; In the resonating step, the high-frequency power supply supplies power of a frequency corresponding to the mode frequency of one of the plurality of vibration modes to at least one of the first and second excitation coils to excite the power supply resonator, thereby causing the first to fourth power supply coils to resonate in one of the plurality of vibration modes.

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