JP2017195707A - Wireless power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless power supply device that can supply power to a wide range and on top of that can make an electric field smaller.SOLUTION: A wireless power supply device 1 includes: a power transmission side resonator 4 including a main coil 41 wound in a spiral in a flat shape and a sub-coil 42 wound in a solenoid in the vicinity of the outer periphery of the main coil 41 without being connected with the outer periphery; and a transmission side controller 5 for controlling excitation of the power transmission side resonator 4. The main coil 41 is provided on the back of an insulation plate 45, and the sub-coil 42 is wound in a solenoid at a side of the insulation plate 45.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wireless power supply device that can wirelessly supply power to a power receiving device.

  Electromagnetic fields can be classified into radiated electromagnetic fields (electromagnetic waves) and non-radiated electromagnetic fields (evanescent fields). Wireless power supply systems that wirelessly supply power from a power transmission side device to a power reception side device using a non-radiating electromagnetic field include a coupled resonator type, an electromagnetic induction type, and a capacitive coupling type. Among these, in the coupled resonator type wireless power supply system, it is easy to transmit power by resonating the power transmitting side resonator of the power transmitting side device and the power receiving side resonator of the power receiving side device via an electromagnetic field. A highly efficient power supply is possible with a simple configuration.

  In Patent Document 1 and Patent Document 2, the inventor of the present application is one of the inventors, and a technique related to a coupled resonator type wireless power supply system is described in them. In Patent Document 1, two power transmission side resonators face each other in the power transmission side device and an alternating current is supplied to only one of them, and the power reception side resonator of the power reception side device is disposed between them. It is disclosed. By using two power transmission side resonators facing each other, power can be supplied to the power receiving side device with high transmission efficiency.

  Patent Document 2 discloses a power transmission side device in which two coils are arranged close to each other in parallel and connected to form one power transmission side resonator. As a result, the electric field that is susceptible to the influence of surrounding dielectrics is confined in the power transmission resonator by two coils, and the power is supplied to the power receiving device mainly by the magnetic field, thereby reducing the transmission efficiency. Is suppressed.

JP 2014-039665 A JP 2014-096872 A

  By the way, various application forms can be considered for the wireless power supply system. Among them, for example, a power transmission side resonator is arranged on a power supply mat, and power is supplied over a wide range regardless of whether the power reception side resonator is located at the center or the periphery of the power supply mat. There is also an application form. Such a power supply mat has many occasions where a human hand touches or comes very close.

  Although the long-term effects on the human body have not been elucidated, it is desirable to reduce the electromagnetic field in terms of the effects on the human body. On the other hand, from the viewpoint of power supply, it is desirable that the electromagnetic field between the power transmission side resonator and the power reception side resonator is somewhat large. Therefore, the inventor of the present application considers that reducing the electric field as shown in Patent Document 2 is very effective in consideration of both the influence on the human body and the aspect of power supply, and the present invention. Devised.

  The present invention has been made in view of the above reasons, and an object of the present invention is a wireless power supply device (power transmission side device) used in a wireless power supply system, which can supply power in a wide range and has an electric field. It is to provide what can reduce the size.

  In order to achieve the above object, a wireless power supply device according to claim 1 is connected to an outer peripheral portion of a main coil wound in a plane in a spiral shape and in the vicinity of the outer peripheral portion of the main coil. A power transmission side resonator having a secondary coil wound in a solenoid shape or in a spiral shape without a solenoid, and a transmission side controller for controlling excitation of the power transmission side resonator. .

  The wireless power supply device according to claim 2 is the wireless power supply device according to claim 1, wherein the main coil is provided on a back surface of the insulating plate, and the sub-coil is solenoid-shaped on a side surface of the insulating plate. It is characterized by being wound around.

  According to the wireless power supply apparatus of the present invention, power can be supplied over a wide range, and the electric field can be reduced.

1 is a side view showing an overall configuration of a wireless power supply apparatus according to an embodiment of the present invention. The structure of the power transmission side resonator of a wireless power supply apparatus same as the above is shown, (a) is a bottom view, and (b) is a side view. It is side surface sectional drawing which expands and shows a part of structure of the power transmission side resonator of a wireless power supply apparatus same as the above. It is a schematic diagram for demonstrating the odd-mode electromagnetic field generated by two coils, (a) shows an electric field, (b) shows a magnetic field. It is a side view which shows typically the mode of the magnetic field of a wireless power supply apparatus same as the above, Comprising: (a) is a case where it has a subcoil, (b) is a thing when a subcoil is omitted. It is a characteristic view which shows the electric field distribution of an experimental result, Comprising: (a) is a thing of the wireless power supply apparatus which concerns on embodiment of this invention, (b) is a thing of the wireless power supply apparatus of a prior art. It is a characteristic view which shows the magnetic field distribution of an experimental result, Comprising: (a) is a thing of the wireless power supply apparatus which concerns on embodiment of this invention, (b) is a thing of the wireless power supply apparatus of a prior art. It is a characteristic view which shows the coupling coefficient of an experimental result, Comprising: (a) is a thing of the wireless power supply apparatus which concerns on embodiment of this invention, (b) is a thing of the wireless power supply apparatus of a prior art. It is a bottom view which shows the power receiving side resonator used in experiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. A wireless power supply apparatus 1 according to an embodiment of the present invention is used in a wireless power supply system 3 as shown in FIG. The wireless power supply system 3 includes a wireless power supply device 1 and a power receiving side device 2 that can receive power supply wirelessly therefrom. The wireless power supply device 1 can be a power supply mat, for example. The power supply mat has a flat surface (surface on the side where the power receiving side device 2 is arranged) and can supply power to the power receiving side device 2 in a wide range regardless of whether it is in the central portion or the peripheral portion. It is.

  The wireless power supply device 1 includes a power transmission side resonator 4 and a transmission side controller 5. The power transmission side resonator 4 has a main coil 41 and a subcoil 42 as shown in FIGS. 2 (a) and 2 (b).

  The main coil 41 is formed by spirally winding an electric conductor covered with an insulating film in a planar manner. The main coil 41 can be wound in a rectangular shape (see FIG. 2A). In addition, it is also possible to use a circular shape or a polygonal shape (for example, a hexagonal shape) or a more complicated shape. In addition, in the main coil 41 shown in FIG. 2A, the sparse winding is performed in the central portion and the winding is densely performed in the peripheral portion for the purpose of uniformizing the strength of the magnetic field generated from the main coil 41. . In addition, a resonance frequency can be adjusted by connecting a capacitor 43 between both ends (inner end and outer end) of the main coil 41.

  The subcoil 42 is obtained by winding an electric conductor covered with an insulating film in a solenoid shape (see FIG. 2B). The subcoil 42 is provided in the vicinity of the outer peripheral portion of the main coil 41 (see FIG. 3), and is provided toward the side where the power receiving side device 2 is disposed. Further, the sub coil 42 is not connected (electrically connected) to any part of the outer peripheral portion of the main coil 41. Further, the resonance frequency can be adjusted by connecting a capacitor 44 between both ends (an end close to the main coil 41 and an end far from the main coil 41) to the sub-coil 42 (see FIG. 2B).

  In such a power transmission side resonator 4, the main coil 41 is disposed on the back surface of the insulating plate 45 using an insulating plate 45 (for example, made of polyethylene), and the sub-coil 42 is disposed on the side surface of the insulating plate 45. If it arrange | positions, the main coil 41 and the subcoil 42 will be easy to arrange | position.

  The transmission side controller 5 controls the excitation of the power transmission side resonator 4. Specifically, the transmission-side controller 5 includes a high-frequency power source 5a and a coupling loop 5b (see FIG. 1). The high frequency power source 5a excites the main coil 41 of the power transmission side resonator 4 through a coupling loop 5b that performs impedance matching. That is, the high frequency power source 5 a outputs the output signal to the coupling loop 5 b, and the coupling loop 5 b is electromagnetically coupled to the main coil 41. The coupling loop 5b can be deformed or replaced with other known impedance matching means. For example, there is a means in which a capacitor is connected in series to the coupling loop 5b to resonate in accordance with a resonance frequency of the power transmission side resonator 4 (more specifically, an odd-mode resonance frequency described later). In this way, the adjustment of the coupling strength between the coupling loop 5b and the main coil 41 can be easily realized by changing the distance between the main coil 41 and the sub-coil 42. It becomes easy to cope with the increase in load in the case of becoming.

  In such a wireless power supply device 1, the main coil 41 excited by the transmission-side controller 5 generates an electromagnetic field (non-radiated electromagnetic field) in the surrounding area. Then, the subcoil 42 is excited by being coupled to the electromagnetic field generated by the main coil 41. The subcoil 42 also generates an electromagnetic field (non-radiating electromagnetic field) in the surrounding area. As a result, the electromagnetic field generated and distributed by the main coil 41 and the subcoil 42 is a combination of the electromagnetic field generated by the main coil 41 and the electromagnetic field generated by the subcoil 42.

  In general, in an electromagnetic field generated and distributed by two coils (denoted by C1 and C2 in FIGS. 4A and 4B), two resonance modes whose frequencies are slightly different from each other, that is, two The electric field generated by the coil has an odd-mode resonance mode that is opposite in phase and an even-mode resonance mode that is in phase with each other. Here, in the odd mode resonance mode, as shown in FIG. 4A, the electric fields (E1 and E2 in the figure) generated by the two coils are combined and are in reverse phase. The applied electric field (E3 in the figure) becomes smaller. The odd mode resonance frequency is lower than the even mode resonance frequency.

  Therefore, since the power transmission side resonator 4 has the main coil 41 and the subcoil 42, when the electric field of the subcoil 42 is combined with the electric field of the main coil 41 and the odd mode resonance mode is used (the odd mode resonance mode is used). When electric power is supplied), the electric field generated from the wireless power supply device 1 is small. Further, the direction of the synthesized electric field approaches a direction parallel to the main coil 41 at many places in the odd-mode resonance mode. Thus, when an odd-mode resonance mode is used, the distance that the electric field substantially reaches (distance from the main coil 41) can be shortened.

  In general, in the odd mode resonance mode, the magnetic fields generated by the two coils are in phase with each other, and in the even mode resonance mode, the magnetic fields are in opposite phases. In the odd-mode resonance mode, as shown in FIG. 4B, the magnetic fields (H1 and H2 in the figure) generated by the two coils are combined (H3 in the figure).

  Since the power transmission side resonator 4 has the main coil 41 and the subcoil 42, the magnetic field of the subcoil 42 is combined with the magnetic field of the main coil 41. As shown in FIG. The magnetic field (indicated by arrows) of the applied magnetic field approaches the vertical direction (the direction of the magnetic field in the central portion) in the peripheral portion (the peripheral portion of the main coil 41). Thereby, the transmission efficiency of the power supply to the power receiving side device 2 can be made uniform (difference due to location can be reduced). As a result, power can be supplied over a wide range. FIG. 5B shows a magnetic field when the power transmission side resonator 4 includes only the main coil 41 and does not include the sub coil 42.

  As described above, the wireless power supply device 1 can supply power over a wide range and can reduce the electric field.

  Therefore, if the wireless power supply device 1 is a power supply mat, it is possible to reduce the electric field in a wide range regardless of whether the power receiving side device 2 is present in the central portion of the surface or the power receiving side device 2 is present in the peripheral portion. Electric power can be supplied.

  Next, the characteristics of the wireless power supply apparatus 1 will be described below in comparison with the wireless power supply apparatus 101 of the prior art. The wireless power supply apparatus 101 of the prior art is configured such that the auxiliary coil 42 of the wireless power supply apparatus 1 is omitted. The following characteristics of the wireless power supply apparatus 1 and the wireless power supply apparatus 101 are experimental results. The diameter of the electric conducting wire used for the main coil 41 and the subcoil 42 was 1 mm.

  The main coil 41 was wound in a rectangular shape with a central portion having a pitch of 20 mm and a peripheral portion having a pitch of 2 mm and a size of 50 cm × 50 cm. A 86 pF capacitor 43 was connected to the main coil 41. The sub-coil 42 was wound in close contact with a three-turn solenoid, and was brought as close to the main coil 41 as possible. A 1.74 nF capacitor 44 was connected to the subcoil 42. The main coil 41 was arranged on the back surface of a polyethylene insulating plate 45 (5 mm thick), and the sub-coil 42 was arranged on the side surface of the insulating plate 45. The wireless power supply device 1 uses an odd-mode resonance mode, the resonance frequency is 509.9 kHz, and the wireless power supply device 101 is the resonance frequency 636.0 kHz. The high frequency power source 5a of the transmission side controller 5 is configured to output 0.5 W of power.

  FIG. 6A shows the electric field distribution of the wireless power supply apparatus 1, and FIG. 6B shows the electric field distribution of the wireless power supply apparatus 101. Curves a and a ′ in the figure are the electric field strengths at a distance of 0 cm from the insulating plate 45 (insulating plate 45 in which the main coil 41 and the subcoil 42 are arranged), and the curves b and b ′ are the insulations. The electric field strength at a distance of 1 cm from the plate 45 and the curves c and c ′ are the electric field strengths at a distance of 2 cm from the insulating plate 45.

  In the wireless power supply device 1, the electric field increases in the peripheral portion of the main coil 41 (near the distance from the center of the main coil 41 is 25 cm), but the electric field is smaller than the wireless power supply device 101 throughout. Yes.

  FIG. 7A shows the magnetic field distribution of the wireless power supply apparatus 1, and FIG. 7B shows the magnetic field distribution of the wireless power supply apparatus 101. Curves d and d 'in the figure are magnetic field strengths at a distance of 0 cm from the insulating plate 45, and curves e and e' are magnetic field strengths at a distance of 1 cm from the insulating plate 45. f and f ′ are the magnetic field strengths at a distance of 2 cm from the insulating plate 45.

  In the wireless power supply device 1, the magnetic field strength is made more uniform than in the wireless power supply device 101.

  FIG. 8A shows a coupling coefficient between the wireless power supply device 1 and the power receiving side device 2, and FIG. 8B shows a connection coefficient between the wireless power supply device 101 and the power receiving side device 2. Is the coupling coefficient. The coil 61 of the power-receiving-side resonator 6 of the power-receiving-side device 2 has a size of 5 cm × 5 cm by winding an electric conducting wire having a diameter of 0.2 mm at a pitch of 1.2 mm and winding it into a rectangle as shown in FIG. A 5.05 nF capacitor 62 was connected to the coil 61. Curves g and g ′ in FIGS. 8A and 8B are coupling coefficients where the distance from the insulating plate 45 is 0 cm, and the curves h and h ′ are those where the distance from the insulating plate 45 is 1 cm. However, the curves i and i ′ are the coupling coefficients when the distance from the insulating plate 45 is 2 cm.

  In the wireless power supply device 1, the coupling coefficient shows extremely good uniformity. Therefore, it can be seen that power can be supplied in a wide range. In the wireless power supply apparatus 101, the coupling coefficient is not more uniform than the wireless power supply apparatus 1.

  The wireless power supply apparatus 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, the electric field distribution, the magnetic field distribution, and the coupling coefficient corresponding to the subcoil 42 slightly change from those described above, but it is also possible to be wound in a spiral shape in a plane.

DESCRIPTION OF SYMBOLS 1 Wireless power supply apparatus 2 Power receiving side apparatus 3 Wireless power supply system 4 Power transmission side resonator 41 Main coil 42 Subcoil 45 Insulating plate 5 Transmission side controller

Claims (2)

A power transmission having a main coil wound in a spiral shape in a plane and a sub-coil wound in a solenoid shape or a spiral shape in a plane without being connected to the outer periphery in the vicinity of the outer periphery of the main coil Side resonators,
A transmission side controller for controlling excitation of the power transmission side resonator;
A wireless power supply device comprising: The wireless power supply device according to claim 1.
The main coil is provided on the back surface of the insulating plate,
The wireless power supply device according to claim 1, wherein the sub coil is wound in a solenoid shape on a side surface of the insulating plate.

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