JP7100845B2 - Power transmission device and power transmission method - Google Patents

Description

The present disclosure relates to a power transmission device and a power transmission method.

Conventionally, a wireless power transfer technique for supplying electric power wirelessly in a building or the like is known. Wireless power transfer has the advantages of being able to reduce the cost of power lines, being able to supply power to places where it is difficult to wire power lines in a building, and being able to supply power over a wide area inside a building. Have.

For example, Patent Document 1 describes a wireless power transfer system that transmits electric power into a building by using a deck plate, a support, or the like as a waveguide. In Patent Document 1, a λ / 4 monopole antenna is provided in the waveguide, coaxial / waveguide conversion is performed, and power propagated in the waveguide via an outlet or the like extending outside the waveguide. The configuration for taking out is described.

Japanese Unexamined Patent Publication No. 2006-166662

By the way, in this kind of wireless power supply, there is a demand that power can be taken out at any place.

In this respect, in the prior art such as Patent Document 1, the electric power extraction position is restricted to the outlet arranged outside the waveguide. Therefore, in such an embodiment, it is necessary to arrange a large number of outlets in the room in advance in order to enable the extraction of electric power at an arbitrary place. Such a configuration is not practical due to space restrictions in the interior space.

The present disclosure has been made in view of the above problems, and an object of the present invention is to provide a power transmission device and a power transmission method which are applied to wireless power transfer and can take out power from an arbitrary place. ..

The main disclosure that solves the above-mentioned problems is
A power transmission device that wirelessly transmits the power of a power supply device to a power receiving device.
A waveguide that propagates electromagnetic waves transmitted from the oscillator of the power supply device to the hollow region inside itself.
A plurality of antenna portions that are arranged in the waveguide along the extending direction and resonate with the electromagnetic wave to recover the electric power of the electromagnetic wave.
It is connected to each of the plurality of antenna portions in the external region of the waveguide, and when the power receiving resonator of the power receiving device is arranged so as to face itself, it is electromagnetically coupled to the power receiving resonator. A plurality of resonators that transmit the power recovered by the antenna unit to the power receiving resonator, and
It is a power transmission device provided with.

Also, in other aspects,
It is a power transmission method using the above-mentioned power transmission device.

According to the power transmission device according to the present disclosure, it is possible to take out power from an arbitrary place in wireless power supply.

The figure which shows an example of the whole structure of the wireless power transfer system which concerns on 1st Embodiment The figure which shows the detailed structure of the power transmission apparatus applied to the wireless power transfer system of FIG. 1 which concerns on 1st Embodiment. The figure which shows the detailed structure of the resonator of the power transmission apparatus which concerns on 1st Embodiment. The figure which shows an example of the electric field distribution generated by the electromagnetic wave propagating in the waveguide which concerns on 1st Embodiment. The figure which shows an example of the structure of the power transmission apparatus which concerns on 2nd Embodiment A diagram showing an example of the relationship between the frequency of electromagnetic waves and the high-intensity points of the electric field distribution generated in the waveguide. A diagram showing another example of the relationship between the frequency of electromagnetic waves and the high-intensity points of the electric field distribution generated in the waveguide.

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same function are designated by the same reference numerals, so that duplicate description will be omitted.

(First Embodiment)
[Overall configuration of wireless power transfer system]
FIG. 1 is a diagram showing an example of the overall configuration of the wireless power transfer system U. FIG. 2 is a diagram showing a detailed configuration of a power transmission device A applied to the wireless power transfer system U of FIG. FIG. 3 is a diagram showing a detailed configuration of the resonator 4 of the power transmission device A.

FIG. 4 is a diagram showing an example of an electric field distribution generated by an electromagnetic wave F propagating in the waveguide 2. FIG. 4 corresponds to a side sectional view (position of TT in FIG. 2) cut along the longitudinal direction of the waveguide 2. In FIG. 4, the vertical arrow E represents an electric line of force and the dot H represents a magnetic force line.

The power transmission device A according to the present embodiment includes a waveguide 2, a plurality of antenna units 3 (3a, 3b, 3c), and a plurality of resonators 4 (4a, 4b, 4c).

As shown in FIG. 1, the power transmission device A propagates the electromagnetic wave F transmitted from the oscillator built in the power supply device 1 into the waveguide 2 and externally via the antenna unit 3 and the resonator 4. It is sent to the power receiving device 5. A plurality of sets of the antenna portion 3 and the resonator 4 are arranged along the longitudinal direction in which the waveguide 2 extends, and the power receiving device 5 uses any of the plurality of sets of the antenna portion 3 and the resonator 4. The structure is such that power can be freely taken out.

In addition, in FIGS. 2 and 4, different reference numerals 3a, 3b, and 3c are attached to each of the three antenna portions 3 arranged at different positions. Further, different reference numerals 4a, 4b, and 4c are attached to each of the three resonators 4 arranged at different positions. however. When any of these is not particularly distinguished, the description will be simply referred to as "antenna unit 3" and "resonator 4".

The power supply device 1 is a power supply that generates high-frequency power by a built-in oscillator and sends an electromagnetic wave F into the waveguide 2. As the oscillator of the power supply device 1, for example, a magnetron oscillator, a klystron oscillator, a gun oscillator, or the like, which can output a large amount of electric power, is used. When changing the frequency, it is desirable to use a semiconductor oscillator (inverter) and a semiconductor amplifier using GaN or the like.

The power supply device 1 according to the present embodiment electromagnetically couples its own resonator 1S with the resonator 4 of the power transmission device A, and sends high-frequency power generated by the built-in oscillator to the resonator 4. Then, the high-frequency power transmitted from the power supply device 1 to the resonator 4 excites the antenna portion 3 connected to the resonator 4, and generates an electromagnetic wave F in the waveguide 2. Here, the power transmission side also uses non-contact power supply, but it is also possible to supply power directly from the high-frequency cable into the waveguide 2 using a λ / 4 antenna without using non-contact power supply.

The electromagnetic wave F transmitted by the power supply device 1 is typically a single-frequency electromagnetic wave F in the microwave or millimeter-wave frequency band, for example, a single-frequency electromagnetic wave selected from the band of the ISM band. F is used. However, since the resonance state in each antenna unit 3 can be optimized by changing the frequency of the electromagnetic wave F, the frequency may be changed (described later in the second embodiment). Further, when power is distributed to a plurality of power receiving devices 5, the power supply device 1 selects two or more frequencies from the microwave or millimeter wave frequency band in order to optimize the resonance state in each power receiving unit, and a plurality of frequencies are selected. The electromagnetic wave F of the frequency may be superposed and transmitted.

The waveguide 2 propagates the electromagnetic wave F transmitted from the power supply device 1 to the hollow region inside itself. The waveguide 2 is composed of a plurality of metal walls arranged so as to form a hollow region. More preferably, the waveguide 2 is configured such that a metal wall surrounds the entire circumference of the hollow region. This allows the waveguide 2 to function like a cavity resonator.

The waveguide 2 has, for example, a square tube having a rectangular cut surface. However, the shape of the waveguide 2 is not particularly limited in the present invention as long as a hollow region propagating the electromagnetic wave F is formed inside, and the shape of the waveguide 2 is a flat plate shape in which the hollow region extends two-dimensionally inside. Alternatively, the hollow region may have a curved shape or the like.

The waveguide 2 may be configured by using a member generally used as a building structure such as a deck plate, a support column, or a pipe of a handrail.

An opening 2t is formed on the wall surface of the waveguide 2 at a position where each of the plurality of antenna portions 3 is arranged. A leader wire connected to each of the plurality of antenna portions 3 is inserted through the opening 2t, and the leader wire is drawn out from the inside of the waveguide 2 to the outside of the waveguide 2. The diameter of the opening 2t is set to be smaller than 1/2 of the wavelength of the electromagnetic wave F from the viewpoint of preventing the electromagnetic wave F in the waveguide 2 from leaking to the outside of the waveguide 2 from the opening 2t. There is.

In the waveguide 2, the electromagnetic wave F transmitted from the power supply device 1 is reflected on the wall surface to generate various resonance states, and an electric field distribution is generated (see FIG. 4). In the electric field distribution generated in the waveguide 2, typically, a position where the electric field strength is strong and a position where the electric field strength is weak are sequentially distributed along the longitudinal direction of the waveguide 2. Note that FIG. 4 shows the electric field distribution when the electromagnetic wave F is propagated in the TE _0n mode assuming that the height of the waveguide 2 is λ / 2 or less and the width is λ / 2 or more (details). Will be described later).

The antenna unit 3 is arranged in the waveguide 2 and resonates with the electromagnetic wave F to recover the electric power of the electromagnetic wave F. That is, the electromagnetic wave F propagating in the waveguide 2 is taken out of the waveguide 2 by the antenna unit 3.

The antenna portion 3 is composed of, for example, a monopole antenna having a metal wall surface of the waveguide 2 as a ground plane. The monopole antenna is arranged so as to extend in parallel in the lateral direction in the waveguide 2, for example. The antenna unit 3 has a shape that is highly sensitive to, for example, the frequency band of the electromagnetic wave F propagated in the waveguide 2 (for example, 1 GHz to 50 GHz), and is, for example, λ with respect to the wavelength λ of the electromagnetic wave F. The length is set to about 4/4.

Each of the plurality of antenna portions 3 is arranged along the longitudinal direction in which the waveguide 2 extends. Each of the plurality of antenna portions 3 is arranged at a position where the electric field strength generated in the waveguide 2 becomes strong. The plurality of antenna units 3 are respectively arranged at high-strength points of electric field strength appearing at predetermined intervals along the extending direction of the waveguide 2, for example, when an electromagnetic wave is propagated in the TE _0n mode. (See FIG. 4).

Each of the plurality of antenna units 3 is connected to a separate resonator 4. Then, the electric power of the electromagnetic wave F collected by each of the plurality of antenna units 3 is transmitted to the external power receiving device 5 of the waveguide 2 by the resonator 4 connected to the antenna unit 3.

The antenna portion 3 and the resonator 4 are connected to each other via a lead wire inserted through an opening 2t formed in the waveguide 2.

The plurality of resonators 4 are arranged in the external region of the waveguide 2 so as to correspond to each of the plurality of antenna portions 3 disposed in the waveguide 2. More specifically, the resonator 4a is conductively connected to the antenna portion 3a, the resonator 4b is conductively connected to the antenna portion 3b, and the resonator 4c is conductively connected to the antenna portion 3c.

The resonator 4 receives power of the electromagnetic wave F transmitted from the antenna unit 3 when the power receiving resonator 5S of the power receiving device 5 is arranged so as to face itself by using electromagnetic coupling. It is transmitted to the resonator 5S in a non-contact manner. On the other hand, the resonator 4 can have a structure that does not generate radiation by itself by adopting an open ring type or the like, and when the power receiving resonator 5S is not arranged so as to face itself, the antenna portion 3 The power of the electromagnetic wave F transmitted from the antenna F is reflected to the antenna unit 3 as it is without being emitted to the external space.

The resonator 4 (and the power receiving resonator 5S) is preferably a resonator having a structure in which an open portion is formed in a part of a closed curved line (typically, it has a ring shape and has an open ring. Also called a resonator) is used. The open ring resonator is particularly useful because it has low radiation loss and high transmission efficiency can be obtained in a wide frequency band.

The resonator 4 configured as an open ring resonator (the same applies to the power transmitting resonator 1S and the power receiving resonator 5S) is configured by forming a metal wire into a ring shape and bringing both ends close to each other (see FIG. 3). The metal wire of the resonator 4 is set to an odd multiple of ½ of the wavelength of the high-frequency power to be transmitted and received so that both ends having the maximum potential difference are close to each other. Further, the resonator 4 and the power receiving resonator 5S are arranged so as to face each other with the center points C0 facing each other in a plan view, and the line C1 connecting the open portion and the center point C0 in the resonator 4 , The angle formed between the open portion of the power receiving resonator 5S and the line C2 connecting the center point C0 (that is, the circumferential direction of the ring between the open end of the resonator 4 and the open end of the power receiving resonator 5S). The angle difference) is arranged so as to have an angle of, for example, 90 ° or more, more preferably 180 °. With this configuration, both the resonance of the magnetic field and the resonance of the electric field are in phase between the resonator 4 and the power receiving resonator 5S, and the resonance is the strongest (also referred to as phase adjustment coupling). This enables, for example, almost 100% power transmission even at a distance of about 1/4 of the wavelength. The resonator 4 and the power transmission resonator 1S also have the same arrangement relationship as the resonator 4 and the power receiving resonator 5S.

That is, of the plurality of resonators 4, only the one in which the power receiving resonator 5S of the power receiving device 5 is arranged to face each other functions as a power extraction unit, and the other one functions as a reflector. For example, as shown in FIG. 2, when the power receiving resonator 5S is arranged so as to face the resonator 4b, the resonator 4b receives the power of the electromagnetic wave F transmitted from the antenna portion 3b. It is transmitted to the resonator 5S. On the other hand, the resonator 4a and the resonator 4c reflect the power of the electromagnetic wave F transmitted from the antenna portion 3a and the antenna portion 3c, respectively, to the antenna portion 3a and the antenna portion 3c as they are. That is, the antenna portion 3a and the antenna portion 3c, and the resonator 4a and the resonator 4c are equivalently de-energized.

In the power transmission device A, in this way, the antenna portion 3 at the unused portion is put into a lossless state without causing the radiation of the electromagnetic wave F due to the total reflection in the resonator 4, and only from the antenna portion 3 at the used portion. It is possible to take out the electromagnetic wave F propagating in the waveguide 2 as electric power.

The power receiving device 5 includes, for example, a rectifier circuit that rectifies high-frequency power received from the power receiving resonator 5S, a battery that charges DC power rectified by the rectifier circuit, and the like. Alternatively, an antenna similar to that of the antenna unit 3 can be placed in the power receiving resonator 5S of the power receiving device 5 to supply high frequency power to another waveguide. In this way, it is also possible to connect and use a plurality of waveguides.

[Concrete example]
Here, with reference to FIGS. 2 and 4, an example of the design of the waveguide 2 and the behavior of the electromagnetic wave F in the waveguide 2 will be described.

Here, a design mode of the waveguide 2 in the case where the electromagnetic wave F is propagated in the TE _0n mode to the waveguide 2 of FIG. 2 will be described. Hereinafter, the upward direction of FIG. 2 will be described as the height direction of the waveguide 2, and the depth direction of FIG. 2 will be described as the width direction of the waveguide 2.

As shown in FIG. 4, the electric field distribution generated by the electromagnetic wave F propagating in the TE _0n mode is such that the electric lines of force extend in the direction perpendicular to the longitudinal direction of the waveguide 2 and the electric field strength is strong (hereinafter referred to as “the electric field strength”). , "High-strength points") and weak positions occur in order along the longitudinal direction of the waveguide 2. Therefore, the state in which the electromagnetic wave F propagates in the TE _0n mode is preferable in that the antenna unit 3 can efficiently recover the electric power of the electromagnetic wave F. In particular, among the TE _0n modes, the TE ₀₁ mode in which the multiple mode does not occur is more preferable.

The propagation constant γ of the electromagnetic wave F propagating in the TE mode is generally expressed by the following equation (1).

The condition that the electromagnetic wave F is in the TE _0n mode is a condition that the propagation constant γ is a pure imaginary number when m = 0, that is, the width b of the waveguide 2 satisfies b> λ / 2. be. At this time, in order to propagate only the TE _0n mode, the height a of the waveguide 2 may be set so as to satisfy a <λ / 2. For example, when the frequency of the electromagnetic wave F is 5.8 GHz, the height a of the waveguide 2 may be 2.6 cm or less because λ = 5.17 cm.

As a result, the electromagnetic wave F propagating in the waveguide 2 is only in the TE _0n mode with an arbitrary value of b satisfying b> λ / 2, and the electric field at resonance is waveguide as shown in FIG. It is perpendicular to the upper and lower surfaces of the tube 2.

At this time, the in-tube wavelength λg in the waveguide 2 is generally expressed by the following equation (2).

Then, if the antenna portion 3 (for example, a λ / 4 monopole antenna) is inserted from the upper and lower surfaces at a position corresponding to the wavelength λg in the tube, the electric field becomes parallel to the extending direction of the antenna portion 3 and the antenna portion 3 can efficiently recover the electric power of the electromagnetic wave.

For example, if the width b of the waveguide 2 is 4 cm, only the TE ₀₁ mode can propagate from the equation (1). Then, when an electromagnetic wave F of 5.8 GHz is put in the waveguide 2, the wavelength in the tube is λg = 6.78 cm, and in the waveguide 2, the pitch is λg / 2 = 3.4 cm, and the high-strength point of the electric field strength is reached. That is, an electric field concentration point is generated. When the electromagnetic wave F in the TE ₀₁ mode propagates, the electric field becomes zero at the tube wall of the waveguide 2, so that the electric field is concentrated at the center of the waveguide 2 in the width direction.

At this time, the waveguide 2 is more preferably configured such that both ends in the longitudinal direction are closed with a metal wall. As a result, the waveguide 2 can be configured as a cavity resonator, and a high-intensity point with higher strength can be generated in the waveguide 2.

Further, the frequency of the electromagnetic wave F transmitted into the waveguide 2 is more preferably set to be equal to or higher than the cutoff frequency of the TE ₀₁ mode and lower than the cutoff frequency of the propagation mode other than the TE ₀₁ mode. As a result, only the TE ₀₁ mode can be generated among the modes of TE _0n , so that the high-intensity points of the electric field distribution of the electromagnetic wave F can be more concentrated. As the frequency of the electromagnetic wave F propagating in the waveguide 2, the frequency at which the electromagnetic wave F in the TE ₀₁ mode is generated is the lowest frequency. Then, as the frequency of the electromagnetic wave F rises from the frequency, the electromagnetic wave F in the multiple mode is generated in the waveguide 2.

[effect]
As described above, the power transmission device A according to the present embodiment has a waveguide 2 and a waveguide that propagate the electromagnetic wave F of a predetermined frequency transmitted from the antenna of the power supply device 1 to the hollow region inside itself. A plurality of antenna portions 3 in which the waveguide 2 is arranged along the extending longitudinal direction in 2 and resonates with the electromagnetic wave F to recover the power of the electromagnetic wave F, and a plurality of antenna portions 3 in the external region of the waveguide 2. When the power receiving resonator 5S of the power receiving device 5 is arranged so as to be connected to each of the antenna portions 3 of the above and to face itself, it is electromagnetically coupled to the power receiving resonator 5S to the power receiving resonator 5S. It is provided with a plurality of resonators 4 for transmitting the power recovered by the antenna unit 3.

Therefore, the power transmission device A according to the present embodiment is attached to the power receiving resonator 5S when the power receiving resonator 5S of the power receiving device 5 is arranged so as to face any of the plurality of resonators 4. On the other hand, power can be transmitted wirelessly. The arrangement position of the resonator 4 does not need to be exposed to the indoor space unlike the outlet, and power can be supplied through the floor plate or the ceiling plate in the building. Therefore, according to the power transmission device A according to the present embodiment, a large number of power outlets (that is, the resonator 4) can be arranged by utilizing the surplus space, and power can be taken out from an arbitrary place. It is possible.

Further, since the power transmission device A according to the present embodiment is configured to transmit power using the waveguide 2, the loss is smaller and the area is wider than that in the mode of power transmission using a coaxial cable or the like. Power can be transmitted over. In addition, since the power transmission device A according to the present embodiment has a configuration in which power is taken out from the inside of the waveguide 2 via the antenna unit 3 and the resonator 4, the unused antenna unit 3 and the like are used. Power transfer is possible without causing radiation loss.

Further, each of the plurality of antenna portions 3 according to the present embodiment is arranged in the waveguide 2 at a position where the electric field strength of the electric field distribution generated by the electromagnetic wave F increases. As a result, the antenna unit 3 can efficiently recover the electric power of the electromagnetic wave F propagating in the waveguide 2.

Further, each of the plurality of resonators 4 according to the present embodiment is composed of a resonator (typically, an open ring resonator) having a structure in which an open portion is formed in a part of a closed curved line. This makes it possible to reduce the radiation loss in the resonator 4 and to obtain high transmission efficiency. Further, since the resonator 4 can secure high transmission efficiency in a wide frequency band, it is possible to secure high transmission efficiency even when the frequency of the electromagnetic wave F is changed.

Further, the tube walls extending along the longitudinal direction of the waveguide 2 according to the present embodiment are arranged so that the distance between the two opposing surfaces is ½ or less of the wavelength of the electromagnetic wave F. It has a flat plate portion. As a result, the propagation mode of the electromagnetic wave F generated in the waveguide 2 can be limited to the TE _0n mode only, and a situation occurs in which the high-intensity points of the electric field distribution of the electromagnetic wave F in the waveguide 2 are dissipated. It is possible to suppress. As a result, the antenna unit 3 can efficiently recover the electric power of the electromagnetic wave F propagating in the waveguide 2.

However, the propagation mode in the waveguide is not limited to the TE _0n mode, and may be another mode as long as it can propagate to a long distance such as TE _mn and TM _mn . Therefore, the shape of the waveguide 2 may be tubular as long as a part of the width of the cross section is λ / 2 or more, and if it is a metal container with little dielectric loss, conductor loss, and radiation loss from the tube wall. Alternatively, it may be box-shaped or the like. Further, by filling the inside of the waveguide 2 with a lossless dielectric material, it is possible to shorten the effective wavelength of the electromagnetic wave F, and thereby the tube diameter can be reduced. It can also be applied to pipes and containers in which the surface or inner surface of a plastic pipe is coated with a metal film.

(Second embodiment)
Next, the power transmission device A according to the second embodiment will be described with reference to FIGS. 5 to 7.

FIG. 5 is a diagram showing an example of the configuration of the power transmission device A according to the present embodiment.

The power transmission device A according to the present embodiment is different from the first embodiment in that the power transmission device A includes a control device 6 for controlling the frequency of the electromagnetic wave F propagating in the waveguide 2.

In the first embodiment, each of the plurality of antenna portions 3 is arranged at a high intensity point of the electric field distribution generated in the waveguide 2. However, the high-intensity point may actually be displaced due to distortion of the cross-sectional shape of the waveguide 2 or an obstacle such as an antenna portion 3 placed in the waveguide 2. Further, when the size of the waveguide 2 in the height direction or the width direction is longer than the wavelength of the electromagnetic wave F, the high-intensity point changes rapidly depending on the frequency.

Therefore, in the power transmission device A according to the present embodiment, the electromagnetic wave propagating in the waveguide 2 in the control device 6 so that the arrangement position of the antenna portion 3 to be used becomes a high intensity point of the electric field distribution. Control the frequency of F.

The control device 6 detects, for example, the level of electric power received by the power receiving device 5 by communicating with the power receiving device 5. Then, the control device 6 outputs a command signal instructing the frequency of the generated electromagnetic wave to the power supply device 1, thereby feeding back the frequency of the electromagnetic wave so that the power received by the power receiving device 5 is maximized. Control (dotted arrows in FIG. 5 represent communication signals). This makes it possible to efficiently supply power to the power receiving device 5.

The control device 6 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input port, an output port, a communication controller, and the like. The function of the control device 6 is realized, for example, by the CPU referring to a control program or various data stored in a ROM or RAM.

The oscillator of the power supply device 1 according to the present embodiment is configured to have a variable frequency of high frequency power (that is, electromagnetic wave F) to be transmitted.

FIG. 6 is a diagram showing an example of the relationship between the frequency of the electromagnetic wave F and the high-intensity point of the electric field distribution generated in the waveguide 2.

Specifically, FIG. 6 shows the high-intensity points of the electric field distribution calculated by electromagnetic field simulation when the frequency of the electromagnetic wave F is changed in the waveguide 2 shown in the above [Specific example].
Each plot in FIG. 6 represents:
○ mark: High-intensity point of electric field distribution when the frequency of electromagnetic wave F is 5.121 GHz × mark: High-intensity point of electric field distribution when the frequency of electromagnetic wave F is 5.223 GHz

In FIG. 6, the horizontal axis represents the position of the waveguide 2 in the longitudinal direction, and the vertical axis represents the position of the waveguide 2 in the width direction. When the frequency of the electromagnetic wave F is 5.121 GHz and 5.223 GHz, the electromagnetic wave F propagates only in the TE ₀₁ mode.

In FIG. 6, when the frequency of the electromagnetic wave F is 5.121 GHz, 29 high-intensity points (optimal points) are generated in approximately 100 cm in the longitudinal direction of the waveguide 2. On the other hand, when the frequency of the electromagnetic wave is 5.223 GHz, 30 high-intensity points (optimal points) are generated in approximately 100 cm in the longitudinal direction of the waveguide 2. Then, high-intensity points are generated at different positions in the longitudinal direction of the waveguide 2 when the frequency of the electromagnetic wave is 5.112 GHz and when the frequency of the electromagnetic wave is 5.223 GHz.

The control device 6 changes the frequency of the electromagnetic wave F transmitted from the power supply device 1 into the waveguide 2 so as to sweep a predetermined frequency band, for example. Then, the control device 6 detects the power received by the power receiving device 5 by communicating with the power receiving device 5, and controls the frequency of the electromagnetic wave so that the power received by the power receiving device 5 is maximized.

When there are a plurality of power receiving devices 5, it is conceivable that the optimum frequency for each power receiving device 5 is different. In that case, the power supply device 1 may transmit electromagnetic waves F having a plurality of frequencies into the waveguide 2. Then, the control device 6 may control each of the plurality of frequencies so that the power received by each of the plurality of power receiving devices 5 is maximized.

FIG. 7 is a diagram showing another example of the relationship between the frequency of the electromagnetic wave F and the high-intensity point of the electric field distribution generated in the waveguide 2. FIG. 7 shows the high-strength points of the electric field distribution when the width b of the waveguide 2 is expanded to 6 cm in the waveguide 2 shown in the above [Specific Example] by electromagnetic field simulation. be.

Each plot in FIG. 7 represents:
○ mark: High intensity point of electric field distribution when the frequency of electromagnetic wave F is 5.159 GHz ◇ Mark: High intensity point of electric field distribution when the frequency of electromagnetic wave F is 5.200 GHz + mark: High intensity point of electric field distribution when the frequency of electromagnetic wave F is 5.200 GHz 5. High-strength point of electric field distribution at 213 GHz

In FIG. 7, the horizontal axis represents the position of the waveguide 2 in the longitudinal direction, and the vertical axis represents the position of the waveguide 2 in the width direction. When the frequency of the electromagnetic wave F is 5.159 GHz, the electromagnetic wave F propagates only in the TE ₀₁ mode. On the other hand, at 5.200 GHz and 5.21 GHz, the electromagnetic wave F propagates in a mixture of TE ₀₂ mode and TE ₀₁ mode (here, the electric field strength in TE ₀₁ mode is small, so the illustration is omitted. ).

In the embodiment of FIG. 7, for example, the antenna unit 3 is separately arranged at each position of the high-strength point where the electric field becomes high-strength in the TE ₀₁ mode and the high-strength point where the electric field becomes high-strength in the TE ₀₂ mode. It may be set. This makes it possible to secure more power extraction positions.

On the other hand, in this embodiment as well, the control device 6 may control the frequency of the electromagnetic wave so that the position of the antenna portion 3 to be used becomes a high-intensity point of the electric field distribution.

As described above, the power transmission device A according to the present embodiment controls the predetermined frequency of the electromagnetic wave F transmitted by the oscillator of the power supply device 1 to adjust the electric field distribution generated by the electromagnetic wave F in the waveguide 2. The control device 6 is further provided. As a result, the position where the electric field strength increases (that is, the antinode position of the standing wave) can be controlled, so that the electric power can be efficiently taken out at any place.

Further, the control device 6 according to the present embodiment communicates with the power receiving device 5 and feedback-controls the predetermined frequency of the electromagnetic wave F based on the electric power received by the power receiving device 5. This makes it possible to control a predetermined frequency of the electromagnetic wave F transmitted by the oscillator of the power supply device 1 so that the electric field strength increases at the position of the antenna portion 3 to be used.

(Other embodiments)
The present invention is not limited to the above embodiment, and various modifications can be considered.

In the above embodiment, as an example of the power supply device 1, an embodiment in which the electromagnetic wave F is disposed outside the waveguide 2 and is transmitted into the waveguide 2 via a resonator and an antenna is shown. However, the mode in which the power supply device 1 transmits the electromagnetic wave F into the waveguide 2 is arbitrary, and the electromagnetic wave F is directly transmitted into the waveguide 2 without interposing the resonator 4 and the antenna unit 3. It may be an embodiment.

On the other hand, as in the above embodiment, in the case where the power supply device 1 is arranged outside the waveguide 2 and the electromagnetic wave F is transmitted into the waveguide 2 via the resonator 4 and the antenna portion 3. It is desirable that the position of the antenna portion 4 on the power transmission side is a place where the electromagnetic field becomes high due to resonance due to reciprocity.

Further, in the above embodiment, the waveguide 2 having a rectangular cross section has been described as an example of the waveguide 2, but the power transmission device A according to the present invention applies the waveguide 2 having an arbitrary shape. Is possible. Depending on the shape of the waveguide 2, the electric field distribution in the waveguide 2 changes, and the power recovery efficiency by the antenna unit 3 drops. However, even in this case, since no direct loss occurs, the antenna portion 3 can be absorbed through rereflection and multiple reflection.

Further, in the above embodiment, a monopole antenna is shown as an example of the antenna unit 3. As the antenna unit 3, other antennas such as a dipole antenna and a loop antenna may be used.

Further, in the above embodiment, an open ring resonator is shown as an example of the resonator 4. As the resonator 4, another resonator such as a ring resonator or a spiral resonator may be used.

Further, in the above embodiment, as an example of the power transmission device A, an embodiment in which one resonator 4 is connected to one antenna unit 3 is shown. However, from the viewpoint of amplifying the electric power, the electric power may be transmitted from the plurality of antenna units 3 to one resonator 4.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above.

According to the power transmission device according to the present disclosure, it is possible to take out electric power from any place.

1 Power supply 2 Waveguide 2t Opening 3a, 3b, 3c Antenna part 4a, 4b, 4c Resonator 5 Resonator 5S Resonator for power reception 6 Control device A Power transmission device F Electromagnetic wave U Wireless power supply system

Claims (7)

A power transmission device that wirelessly transmits the power of a power supply device to a power receiving device.
A waveguide that propagates electromagnetic waves transmitted from the oscillator of the power supply device to the hollow region inside itself.
A plurality of antenna portions that are arranged in the waveguide along the extending direction and resonate with the electromagnetic wave to recover the electric power of the electromagnetic wave.
It is connected to each of the plurality of antenna portions in the external region of the waveguide, and when the power receiving resonator of the power receiving device is arranged so as to face itself, it is electromagnetically coupled to the power receiving resonator. A plurality of resonators that transmit the power recovered by the antenna unit to the power receiving resonator, and
Equipped with,
The resonator has a structure in which an open portion is formed in a part of a closed curve line.
Power transmission device. The power transmission device according to claim 1, further comprising a control device for controlling the frequency of the electromagnetic wave transmitted by the oscillator of the power supply device to adjust the electric field distribution generated by the electromagnetic wave in the waveguide. The power transmission device according to claim 2, wherein the control device communicates with the power receiving device and feedback-controls the frequency of the electromagnetic wave based on the level of the power received by the power receiving device. The power transmission device according to any one of claims 1 to 3, wherein the antenna portion is composed of a monopole antenna having a metal wall surface of the waveguide as a ground plane. Any of claims 1 to 4 , wherein the tube wall extending along the longitudinal direction of the waveguide has a pair of flat plate portions in which the distance between two facing surfaces is set to 1/2 or less of the wavelength of the electromagnetic wave. The power transmission device according to one item. The waveguide has a metal wall arranged so as to surround the entire circumference of the hollow region.
The power transmission device according to any one of claims 1 to 5 , wherein the power supply device is arranged outside the waveguide and transmits the electromagnetic wave into the waveguide via the antenna portion. A power transmission method using the power transmission device according to any one of claims 1 to 6 .

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