JP6156872B2 - Wireless power transmission system - Google Patents

Description

  The present invention relates to a wireless power transmission system that performs wireless power transmission using a non-radiated electromagnetic field.

  Electromagnetic fields can be classified into radiated electromagnetic fields (electromagnetic waves) and non-radiated electromagnetic fields (evanescent fields). Wireless power transmission systems using non-radiated electromagnetic fields include a coupled resonator type, an electromagnetic induction type, and a capacitive coupling type.

  In a wireless power transmission system using a non-radiating electromagnetic field, in general, when the distance between the power transmission side device and the power reception side device becomes long, the power transmission efficiency rapidly decreases. Among the types described above, the coupled resonator type wireless power transmission system has a higher power transmission efficiency when there is a distance. However, as the distance becomes longer, the power transmission efficiency rapidly decreases. The same is true. Therefore, even in a coupled resonator type wireless power transmission system, the distance that satisfies the transmission efficiency permitted in power transmission (power transmission possible distance) is not long.

  For this reason, in a coupled resonator type wireless power transmission system, power transmission is performed by inserting an additional resonator called a repeater between the power transmission side resonator of the power transmission side device and the power reception side resonator of the power reception side device. Efforts have been made to extend the possible distance. For example, Patent Document 1 discloses a coupled-resonator-type wireless device in which a repeater (repeater antenna) having a configuration including a resonator similar to the power transmission-side resonator and a power-receiving-side resonator and its associated circuit is provided. A power transmission system is described.

International Publication WO2009 / 140218

  However, since a repeater having a resonator and its associated circuit as described in Patent Document 1 is large in size and tends to be heavy, it is generally difficult to handle such as a limited installation place.

  The present invention has been made in view of the above reasons, and an object thereof is to provide a wireless power transmission system provided with a small and light repeater.

  In order to achieve the above object, a wireless power transmission system according to claim 1 causes non-radiated electromagnetic fields to cause resonance between a power transmission side resonator of a power transmission side device and a power reception side resonator of a power reception side device. In a coupled resonator type wireless power transmission system that wirelessly transmits power from the power transmission side resonator to the power reception side resonator, a non-radiated electromagnetic field from the power transmission side resonator is input, and the power reception side resonator Including at least one repeater that outputs a non-radiating electromagnetic field toward the power source, the repeater having a power transmission side plate, a power reception side plate, and an intermediate connection line that connects them. It is characterized by.

  According to a second aspect of the present invention, in the wireless power transmission system according to the first aspect, the repeater is configured such that the power transmission side flat plate and the power receiving side flat plate are disk-shaped. .

  The wireless power transmission system according to claim 3 is the wireless power transmission system according to claim 1 or 2, wherein the intermediate connection line is bent.

  A wireless power transmission system according to a fourth aspect of the present invention is the wireless power transmission system according to any one of the first to third aspects, wherein there are a plurality of the power receiving side flat bodies and the intermediate connection line is branched. It is characterized by.

  The wireless power transmission system according to claim 5 is the wireless power transmission system according to any one of claims 1 to 4, wherein there are at least two repeaters, and a partition wall exists between the two repeaters. It is characterized by that.

  According to the present invention, it is possible to provide a wireless power transmission system provided with a small and light repeater.

1 is a schematic side view showing a configuration of a wireless power transmission system according to an embodiment of the present invention. The power transmission side apparatus of a radio | wireless power transmission system same as the above is shown, (a) is a typical perspective view, (b) is a schematic front view of the power transmission side resonator which comprises a power transmission side apparatus. The power receiving side apparatus of a wireless power transmission system same as the above is shown, (a) is a schematic perspective view, and (b) is a schematic front view of a power receiving side resonator constituting the power receiving side apparatus. The repeater of a radio | wireless power transmission system same as the above is shown, (a) is a perspective view, (b) The front view of the power transmission side flat body which comprises a repeater. It is a characteristic view which shows the coupling coefficient of the experiment in the experiment structure of FIG. It is a characteristic view which shows the electric power transmission characteristic of experiment with the experiment structure of FIG. It is a schematic side view which shows the other experimental structure of a wireless power transmission system same as the above. It is a characteristic view which shows the coupling coefficient of the experiment in the experimental configuration of FIG. It is a schematic side view which shows other experimental structure of the wireless power transmission system same as the above. It is a characteristic view which shows the coupling coefficient of another experiment and simulation in the structure of FIG. It is a schematic side view which shows the structure of the wireless power transmission system which concerns on another embodiment of this invention. It is a characteristic view which shows the coupling coefficient of the experiment in the experiment structure of FIG. It is a characteristic view which shows the electric power transmission characteristic of experiment with the experiment structure of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. A wireless power transmission system 1 according to an embodiment of the present invention is a coupled resonator type, and as illustrated in FIG. 1, a power transmission side resonator 21 and a power reception side device 3 of a power transmission side device 2 using a non-radiated electromagnetic field. The power receiving side resonator 31 is caused to resonate and wirelessly transmits power from the power transmitting side resonator 21 to the power receiving side resonator 31. In this wireless power transmission system 1, a non-radiated electromagnetic field from the power transmission side resonator 21 is input between the power transmission side resonator 21 and the power reception side resonator 31, and non-radiation is directed toward the power reception side resonator 31. A repeater 4 that outputs an electromagnetic field is provided.

  As shown in FIG. 2, the power transmission side resonator 21 of the power transmission side device 2 can be a coil formed by winding an electric conductor in a flat and spiral shape, that is, a spiral coil. The power transmission side resonator 21 is excited by a signal from the high frequency power source 23 through an impedance matching unit 22 that performs impedance matching. Typically, the impedance matching means 22 can use a coupling loop that electromagnetically couples to the power transmission side resonator 21, but may have other forms such as a form that is directly connected to the power transmission side resonator 21. .

  As shown in FIG. 3, the power receiving side resonator 31 of the power receiving side device 3 can be a spiral coil. The electric power transmitted to the power receiving resonator 31 is supplied to the load 33 via the impedance matching means 32 that performs impedance matching. The load 33 is a circuit for a required function of the device such as a charging circuit of a portable device in the communication field. The impedance matching unit 32 can typically use a coupling loop that electromagnetically couples to the power receiving resonator 31, but may have other forms such as a form that is directly connected to the power receiving resonator 31, for example. . In the figure, the power receiving side device 3 is drawn with approximately the same size as the power transmission side device 2, but the size of the power receiving side device 3 is not limited and is often smaller than the power transmission side device 2. .

  As shown in FIGS. 1 and 4, the repeater 4 includes a power transmission side flat plate 41 made of a metal material flat plate facing the power transmission side resonator 21, and a metal material flat plate facing the power receiving side resonator 31. The power receiving side flat plate 42 and the intermediate connection line 43 made of a metal wire are electrically connected to each other. The power transmission side flat plate 41 and the power receiving side flat plate 42 may be disk-shaped. The surfaces of the power transmission side flat plate 41 and the power receiving side flat plate 42 may be flat without any unevenness. As a material of the power transmission side flat plate 41, the power receiving side flat plate 42, and the intermediate connection line 43, copper or the like can be used.

  An experiment of the wireless power transmission system 1 using such a repeater 4 will be described. The experimental setup is as follows. That is, each of the power transmission side resonator 21 of the power transmission side device 2 and the power reception side resonator 31 of the power reception side device 3 is a spiral coil having a diameter of 30 cm by winding an electrical conductor having a wire diameter of 1 mm 99 times. Their resonant frequency is about 2.15 MHz. A copper disk having a diameter of 10 cm and a thickness of 0.1 mm was used for the power transmission side plate 41 and the power reception side plate 42 of the repeater 4. The intermediate connection wire 43 was a copper wire having a diameter of 1 mm. Both the distance between the power transmission side resonator 21 and the power transmission side flat plate 41 and the distance between the power reception side resonator 31 and the power reception side flat plate 42 were set to 1 cm. In other experiments and simulations to be described later, parts not particularly mentioned are the same as the experimental configuration described above.

  A curve a in FIG. 5 is a characteristic diagram showing a change in the coupling coefficient between the power transmission side resonator 21 and the power reception side resonator 31 when the length L of the intermediate connection line 43 is changed. Here, a straight intermediate connection line 43 is used, and its length L is the distance between the power transmission side flat plate 41 and the power reception side flat plate 42 of the repeater 4. If the coupling coefficient is large, the power transmission efficiency is high. A curve b in the figure is for comparison, and is a characteristic diagram showing a change in the coupling coefficient when the repeater 4 is removed under the same conditions as the curve a.

  It can be seen from the curve a that even if the length L of the intermediate connection line 43 is extended, the rapid decrease in the coupling coefficient as in the curve b is prevented. Further, at L = 180 cm, which is 6 times the diameter of the power transmitting resonator 21 (and the power receiving resonator 31), a high value of 0.07 is obtained as a coupling coefficient.

  A curve c in FIG. 6 shows a change in power transmission characteristics between the power transmission side resonator 21 and the power reception side resonator 31 when the length L of the intermediate connection line 43 is changed, similarly to the curve a in FIG. FIG. A curve d in the figure is for comparison, and is a characteristic diagram showing a change in power transmission characteristics when the repeater 4 is removed under the same conditions as the curve c.

  It can be seen from the curve c that even if the length L of the intermediate connection line 43 is extended, the rapid decrease in power transmission characteristics as in the curve d is prevented. Further, at L = 180 cm, which is 6 times the diameter of the power transmission side resonator 21 (and the power reception side resonator 31), a high value of −0.75 dB is obtained as the power transmission characteristic. The power transmission characteristic of −0.75 dB indicates that 84% of the power output from the power transmission side resonator 21 is input to the power reception side resonator 31.

  In this way, when the distance between the power transmission side resonator 21 and the power reception side resonator 31 is increased, the intermediate connection line 43 of the repeater 4 is extended to prevent a rapid decrease in power transmission efficiency. be able to. Therefore, the power transferable distance between the power transmission side resonator 21 and the power reception side resonator 31 can be greatly extended.

  In addition, such a repeater 4 is not formed with a special pattern having an inductance component such as a spiral coil on the power transmission side flat plate 41 and the power reception side flat plate 42, has a simple structure, and is small and light. can do. Therefore, the repeater 4 has a large degree of freedom in installation location and is easy to handle.

  Further, since the intermediate connection line 43 of the repeater 4 is made of a metal wire, it can be bent, and since it may be thin, it becomes easier to bend.

  An experiment of the wireless power transmission system 1 using the repeater 4 of the bent intermediate connection line 43 will be described. In this experiment, as shown in FIG. 7, the intermediate connection line 43 was bent by 90 degrees, and a shield plate S grounded was installed between the power transmission side flat plate 41 and the power reception side flat plate 42.

  A curve e in FIG. 8 is a characteristic diagram showing a change in the coupling coefficient between the power transmission side resonator 21 and the power reception side resonator 31 when the length L (L1 + L2) of the bent intermediate connection line 43 is changed. . A curve f in the figure is for comparison and is a characteristic diagram showing a change in the coupling coefficient in the case of the straight intermediate connection line 43. The curve e and the curve f show substantially the same characteristics, and it can be seen that the characteristics are not deteriorated by bending the intermediate connection line 43.

  Thus, the repeater 4 can be installed by appropriately bending the intermediate connection line 43 according to the installation location. For example, when an obstacle exists between the power transmission side resonator 21 and the power reception side resonator 31, the intermediate connection line 43 can be bent and wired so as to avoid this. Moreover, the power transmission side flat plate 41 and the power receiving side flat plate 42 of the repeater 4 may not be parallel.

  Further, the intermediate connection line 43 can be branched by using a plurality of power receiving side flat bodies 42.

  An experiment of the wireless power transmission system 1 in which the power receiving side flat plate 42 is plural and the intermediate connection line 43 is branched will be described. In this experiment, as shown in FIG. 9, the power receiving side flat body 42 is divided into two (power receiving side flat bodies 42 ′, 42 ″), and the intermediate connection line 43 from the power transmission side flat body 41 is branched at a branch point B. Thus, there are two (intermediate connection lines 43 ′ and 43 ″). The length of the intermediate connection line 43 from the power transmission side flat plate 41 to the branch point B, the length of the intermediate connection line 43 ′ from the branch point B to the power reception side flat plate 42 ′, and the power reception side flat plate 42 ′ from the branch point B The length of the intermediate connection line 43 '' up to 'is all 50 cm. When measuring the coupling coefficient and power transmission characteristics on one power receiving flat plate 42 ′, a power receiving resonator 31 ′ having a spiral coil diameter of 30 cm is provided opposite to the one power receiving flat plate 42 ′. When measuring the coupling coefficient and the power transmission characteristic of the other power receiving flat plate 42 ″, the power receiving resonator 31 ″ having a spiral coil diameter of 20 cm facing the other power receiving flat plate 42 ″. Was established.

  In this experimental configuration, the coupling coefficient and the power transmission characteristic between the power transmission side resonator 21 and the power reception side resonator 31 ′ were 0.0655 and −0.672 dB, respectively. The resonance frequency at that time was 2.187 MHz. Further, the coupling coefficient and the power transmission characteristic between the power transmission side resonator 21 and the power reception side resonator 31 ″ were 0.0581 and −0.899 dB, respectively. The resonance frequency at that time was 2.144 MHz.

  Thus, when it is desired to install a plurality of power receiving side devices 3 in various places, the intermediate connection line 43 can be branched by using a plurality of power receiving side flat bodies 42. In this case, each power receiving side resonator 31 can be configured not to receive power transmitted from the power transmitting side resonator 21 by detuning from the resonance frequency when it is not its own power feeding timing. .

  Next, operation analysis of the wireless power transmission system 1 will be described. Curves g and h in FIG. 10 indicate the coupling coefficient between the power transmitting side resonator 21 and the power receiving side resonator 31 when the diameter D of the disk-shaped power transmitting side plate 41 and the power receiving side plate 42 is changed. It is a characteristic view which shows a change. The intermediate connection line 43 is linear, and the length L is 40 cm. Curve g is an experimental value, and curve h is a simulation value with the same configuration as the experiment. Curve i in the figure shows that the number of turns of the spiral coil of the power transmission side resonator 21 and the power reception side resonator 31 is 20, and an external capacitor of 60 pF is connected between both ends of the spiral coil to set the resonance frequency to 3 MHz. Simulation value. In the configuration of the curve i, an electric field is confined to the external capacitance of 60 pF so that almost only a magnetic field is generated between the power transmission side resonator 21 and the power reception side resonator 31.

  It can be seen that the curve i has a very small coupling coefficient compared to the curve h. This indicates that the electric field is important for power transmission in the repeater 4, and the contribution of the magnetic field is very small. Further, in the curves g and h, the coupling coefficient is large when the diameter D of the power transmission side flat plate 41 (and the power reception side flat plate 42) is about half of the diameter of the power transmission side resonator 21 (and the power reception side resonator 31). This is probably because the total amount of charges induced in the power transmission side flat plate 41 (and the power receiving side flat plate 42) at that time is increased.

  Next, a wireless power transmission system 1 'according to another embodiment of the present invention will be described. As shown in FIG. 11, the wireless power transmission system 1 ′ has a configuration similar to that of the repeater 4 described above between the power transmission side resonator 21 of the power transmission side device 2 and the power reception side resonator 31 of the power reception side device 3. Two repeaters 4A and 4B are provided. The power transmission side plate 41A of the repeater 4A is opposed to the power transmission side resonator 21, and the power reception side plate 42B of the repeater 4B is opposed to the power reception side resonator 31. Further, the power receiving side flat plate body 42A of the repeater 4A and the repeater 4B power transmission side flat plate body 41B are opposed to each other via the partition wall W.

  An experiment of such a wireless power transmission system 1 'will be described. A curve j in FIG. 12 is a case where a glass partition wall W having a thickness of 0.6 mm is present between the repeaters 4A and 4B, and the distance M between the power transmission side resonator 21 and the power reception side resonator 31 is changed. It is a characteristic view which shows the change of a coupling coefficient at the time. A curve k in the figure is for comparison, and is a characteristic diagram showing a change in the coupling coefficient when the repeaters 4A and 4B are removed under the same conditions as the curve j.

  It can be seen that the curve j has a very large coupling coefficient compared to the curve k.

  A curve l in FIG. 13 is a case where a glass partition wall W having a thickness of 0.6 mm is present between the repeaters 4A and 4B, and the distance M between the power transmission side resonator 21 and the power reception side resonator 31 is changed. It is a characteristic view which shows the change of the power transmission characteristic at the time. A curve m in the figure is for comparison, and shows characteristics when the repeaters 4A and 4B are removed under the same conditions as the curve l.

  It can be seen that the curve l prevents a rapid decrease in the power transmission characteristics as in the curve m.

  As described above, when the partition wall W exists between the power transmission side resonator 21 and the power reception side resonator 31, if the partition wall W is sandwiched between the repeaters 4A and 4B, the efficiency is achieved via the partition wall W. Power transmission becomes possible. The partition wall W can be of a type such as glass or gypsum board. Depending on the type of the partition wall W, for example, power can be supplied from the room to the outside through the glass window, from the air to the water tank, or from one room to the next room through the wall.

  The wireless power transmission system according to the embodiment of the present invention has been described above. However, the present invention is not limited to that described in the above-described embodiment, and various modifications within the scope of the matters described in the claims. Design changes are possible. For example, between the power transmission side resonator and the power reception side resonator, a number of repeaters can be provided depending on the location, and a partition wall can be appropriately sandwiched between the repeaters.

DESCRIPTION OF SYMBOLS 1 Wireless power transmission system 2 Power transmission side apparatus 21 Power transmission side resonator which comprises power transmission side apparatus 3 Power reception side apparatus 31 Power reception side resonator which comprises power reception side apparatus 4, 4A, 4B repeater 41, 41A, 41B The power transmission side of a repeater Flat plate 42, 42A, 42B Repeater power receiving side flat plate 43, 43A, 43B Repeater intermediate connection line W Bulkhead

Claims (5)

Coupled resonance in which non-radiated electromagnetic field is used to cause power transmission side resonator of power transmission side device and power reception side resonator of power reception side device to resonate and wirelessly transmit power from power transmission side resonator to power reception side resonator In the type of wireless power transmission system,
A non-radiated electromagnetic field from the power transmission side resonator is input, and at least one repeater that outputs the non-radiation electromagnetic field toward the power reception side resonator comprises:
The repeater includes a power transmission side plate, a power reception side plate, and an intermediate connection line that connects the power transmission side plate and the wireless power transmission system. The wireless power transmission system according to claim 1,
In the repeater, the power transmission-side flat body and the power-receiving-side flat body have a disk shape. The wireless power transmission system according to claim 1 or 2,
The wireless power transmission system, wherein the intermediate connection line is bent. The wireless power transmission system according to any one of claims 1 to 3,
A wireless power transmission system, wherein a plurality of power receiving side flat bodies are provided, and the intermediate connection line is branched. In the wireless power transmission system according to any one of claims 1 to 4,
The wireless power transmission system according to claim 1, wherein there are at least two repeaters, and a partition wall exists between the two repeaters.

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