JP6687239B2 - Wireless power supply - Google Patents

Description

  The present invention relates to a wireless power supply device capable of wirelessly supplying power to a power receiving device.

  Electromagnetic fields can be classified into radiated electromagnetic fields (electromagnetic waves) and non-radiated electromagnetic fields (evanescent fields). There are a coupled resonator type, an electromagnetic induction type, a capacitive coupling type, and the like in a wireless power supply system that wirelessly supplies electric power from a power transmission side device to a power reception side device using a non-radiated electromagnetic field. Among these, in the coupled resonator type wireless power supply system, power is transmitted 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 a non-radiated electromagnetic field. The simple structure enables power supply with high transmission efficiency.

  In Patent Documents 1 to 3, the inventor of the present application is one of the inventors, and the techniques related to the coupled resonator type wireless power supply system are described therein. In Patent Document 1, two power transmission side resonators are opposed to 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 arranged between them. It is disclosed. By using the two power transmission side resonators facing each other, it is possible to further improve the transmission efficiency and supply power to the power receiving side device.

  Further, Patent Document 2 discloses a wireless power supply system including a dielectric or magnetic inductor that refracts a non-radiated electromagnetic field from the power transmission side device and guides it toward the power reception side device. By using the inductor, it is possible to further improve the transmission efficiency and supply power to the power receiving side device.

  Further, Patent Document 3 discloses a swimming pool viewing apparatus to which a coupled resonator type wireless power supply system is applied. In this swimming object viewing apparatus, electric power is wirelessly transmitted from the power transmission side device attached to the water tank to the swimming body, which is the power receiving side device in the water tank, using a non-radiated electromagnetic field.

JP, 2014-039665, A JP, 2014-195364, A JP, 2014-223262, A

  By the way, it is desirable to reduce the non-radiated electromagnetic field from the viewpoint of the effect on the human body, although the long-term effect on the human body has not been clarified. As a countermeasure for that, it is conceivable to arrange a shield material that shields the non-radiation electromagnetic field at an appropriate place around the power transmission side device so that the non-radiation electromagnetic field on the outside thereof is reduced. A metal plate is typically considered as the shield material, but the metal plate hides the inside thereof and must be grounded.

  The present invention has been made in view of the above circumstances, and an object thereof is a wireless power supply apparatus (power transmission side apparatus) used in a wireless power supply system, which does not hide the inside and is not grounded. It is to provide one with a good shielding material.

  In order to achieve the above object, the wireless power supply apparatus according to claim 1, wherein at least one power-transmitting-side resonator having a coil, and transmission-side control that controls excitation of the at least one power-transmitting-side resonator. And a shield material in which water is stored and which is arranged around the coil of the at least one power transmission side resonator and shields an electric field of a non-radiated electromagnetic field from the coil. Is characterized by.

  A wireless power supply apparatus according to a second aspect is the wireless power supply apparatus according to the first aspect, wherein the water is tap water.

  According to the wireless power supply apparatus of the present invention, the shield material used for the wireless power supply apparatus does not hide the inside and does not need to be grounded.

It is a side view sectional view showing composition of a wireless power supply unit concerning an embodiment of the present invention. It is a top view which shows the power transmission side resonator of a wireless power supply device same as the above, Comprising: (a) is a circular coil, (b) is a rectangular coil. It is a side view sectional drawing which shows the swimming body ornamentation apparatus to which the same wireless power supply device as the above is applied, (a) has one power transmission side resonator, (b) has two power transmission side resonators. It is a thing. It is a figure which shows the structure of a 1st simulation, (a) is a side view sectional drawing, (b) is a top view. It is a characteristic view which shows the reflection coefficient (S11) in a 1st simulation. It is a characteristic view which shows the change of the amount of electric field energy when changing the thickness of a shield material in a 1st simulation. It is a characteristic view which shows the change of the amount of electric field energy when changing the distance between a water tank and a shield material in a 1st simulation. It is a characteristic view which shows the change of the amount of electric field energy when changing the electric conductivity of the water of a shield material in a 1st simulation. It is a side view which shows the structure of a 2nd simulation, (a) arrange | positions a shield material in the side surface of the short side of a water tank, (b) arrange | positions a shield material in the upper surface side of the water tank. is there. It is a characteristic view which shows the reflection coefficient (S11) in a 2nd simulation. It is a figure which shows the electric field distribution when the shield material is arrange | positioned at the side surface of the short side of a water tank in a 2nd simulation, (a) about resonance frequency 3MHz vicinity, (b) about resonance frequency 300kHz vicinity. Is. It is a figure which shows the electric field distribution when the shield material is arrange | positioned at the upper surface side of the water tank in a 2nd simulation, (a) is a thing near resonance frequency 3MHz, (b) is a thing near resonance frequency 300kHz. It is a figure which shows the electric field distribution in case a shield material is not arrange | positioned near the water tank in a 2nd simulation, (a) is a thing near resonance frequency 3MHz, (b) is a thing near resonance frequency 300kHz. It is a figure which shows the electric field strength outside a shield material when arrange | positioning a shield material to the side surface of the short side of an aquarium in an experiment, (a) about resonance frequency 3MHz vicinity, (b) about resonance frequency 300kHz vicinity. belongs to. It is a figure which shows the electric field strength of the outer side of the shield material when a shield material is arrange | positioned at the upper surface side of a water tank in an experiment, (a) is a thing near resonance frequency 3MHz, (b) is a thing near resonance frequency 300kHz. is there. It is a figure which shows the magnetic field strength of the outer side of the shield material when a shield material is arrange | positioned at the upper surface side of a water tank in an experiment, (a) is a thing near resonance frequency 3MHz, (b) is a thing near resonance frequency 300kHz. is there.

  Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. As shown in FIG. 1, the wireless power supply device 1 according to the embodiment of the present invention includes a power transmission side resonator 2, a transmission side controller 3, and a shield material 4.

  The power transmission side resonator 2 has a coil 21 as shown in FIGS. The coil 21 may be a spiral coil in which an electric conductor wire coated with an insulating film is wound in a planar spiral shape. The coil 21 has a circular shape as shown in FIG. 2A, a rectangular shape as shown in FIG. 2B, or another polygonal shape (for example, hexagonal shape) or a more complicated shape. It can be rolled. Further, the resonance frequency can be adjusted by connecting a capacitor 22 to both ends (inner end and outer end) of the coil 21. Further, the coil 21 may be a solenoid coil in which an electric wire covered with an insulating film is wound in a solenoid shape.

  The transmission side controller 3 controls the excitation of the power transmission side resonator 2. The transmission side controller 3 has a high frequency power supply 3a and a coupling loop 3b in detail (see FIG. 1). The high frequency power supply 3a excites the power transmission side resonator 2 via a coupling loop 3b that performs impedance conversion. That is, the high frequency power supply 3a outputs the output signal to the coupling loop 3b, and the coupling loop 3b is electromagnetically inductively coupled to the coil 21 of the power transmission side resonator 2. The coupling loop 3b can be modified or replaced with another known impedance conversion means.

  In such a wireless power supply device 1, the coil 21 excited by the transmission side controller 3 generates a non-radiation electromagnetic field in the surrounding area.

  The shield material 4 stores water 41. More specifically, the shield material 4 may be configured such that the water 41 is enclosed in a case 42 made of a transparent resin (for example, an acrylic resin). Further, the shield material 4 is arranged in a part around the coil 21 of the power transmission side resonator 2. In FIG. 1, the shield member 4 is arranged on the right side of the coil 21, but any shape and any shape may be arranged.

  The shield material 4 can shield the electric field of the non-radiation electromagnetic field from the coil 21, as shown in a simulation and an experiment described later. The shield material 4 has almost no effect on the magnetic field of the non-radiated electromagnetic field. The shield material 4 has almost no effect on the magnetic field of the non-radiated electromagnetic field, but since it can shield the electric field, the total amount of the non-radiated electromagnetic field outside the shield material 4 (on the side opposite to the coil 21). Can be reduced. When the transparent case is used as the shield material 4, water is also transparent, so that the inner side (on the side of the coil 21) is not hidden, so that the inner side can be visually recognized from the outer side of the shield material 4. Further, since the shield material 4 does not have to be grounded, there is no fear of radiating electromagnetic waves as an antenna due to insufficient grounding, and the shield material 4 may be freely arranged in various places without considering grounding. You can

  The wireless power supply device 1 having the configuration described above can be applied to various wireless power supply systems. For example, as shown in FIG. 3 (a), it can be used for the swimming pool viewing apparatus 5. In the swimming object viewing device 5, the power transmission side resonator 2 of the wireless power supply device 1 is provided at the bottom of the water tank 6. The swimming body (power receiving side device) 7 including the power receiving side resonator 71 is put into the water tank 6 together with water. The swimming body 7 is wirelessly supplied with power from the wireless power supply device 1 using a non-radiated electromagnetic field. The shield material 4 is arranged on the side surface of the water tank 6 or the like.

  In the swimming object viewing apparatus 5, if the shield member 4 is arranged between the person who watches the water tank 6 and the water tank 6, the amount of the non-radiated electromagnetic field that hits the human body can be reduced without disturbing the watching. The shield material 4 can be freely arranged in any shape.

  Further, in the swimming object viewing device 5, in the wireless power supply device 1, as shown in FIG. 3B, the power transmission side resonator 2 ′ having the same structure as the power transmission side resonator 2 is provided in the lid of the water tank 6. Can be provided. The power transmission side resonator 2'has a coil 21 ', and a resonance frequency can be adjusted by connecting a capacitor 22' between both ends (inner end and outer end) thereof.

  The power transmission side resonator 2 ′ in the lid of the water tank 6 is excited by being coupled to the non-radiation electromagnetic field from the power transmission side resonator 2 that has reached there, and generates the non-radiation electromagnetic field in the downward direction. . As a result, the power receiving side resonator 71 of the swimmer 7 is supplied with power by the non-radiating electromagnetic field from the power transmitting side resonator 2'in addition to the non-radiating electromagnetic field from the power transmitting side resonator 2. It should be noted that the power transmission side resonator 2 ′ operates by itself, and no coupling loop or high frequency power supply for that purpose is provided.

  Next, a simulation and an experiment performed on the wireless power supply device 1 will be described. As the simulation software, HFSS of ANSYS Inc. was used. The simulation is divided into a first simulation and a second simulation. The experiment corresponds to the second simulation. In these simulations and experiments, the power transmission side resonator 2 of the wireless power supply device 1 was provided at the bottom of the water tank 6, and the power transmission side resonator 2 ′ was provided at the lid of the water tank 6. Water was introduced into the water tank 6.

  The first simulation will be described first. In the first simulation, the water tank 6 has a cylindrical shape with a diameter of 15 cm and a height of 10 cm. The shield member 4 (water 41) was in the shape of a cylinder having a height of 10 cm, and was arranged so as to surround the side surface of the water tank 6 as shown in FIGS. 4 (a) and 4 (b). The thickness of the case 42 of the shield material 4 was zero. In FIGS. 4A and 4B, the cylindrical space (gray portion) indicated by reference numeral S outside the shield material 4 has a thickness of 5 cm and a height of 10 cm, and electric field energy or magnetic field energy is integrated. This is a range for deriving the amount of electric field energy or the amount of magnetic field energy described later.

  The coil 21 of the power transmission side resonator 2 was formed by winding an electric conductor wire having a diameter of 1 mm in a circular shape and having 15 windings and a diameter of 15 cm. A 4.7 nF capacitor 22 was connected to the coil 21 so that the resonance frequency was around 700 kHz. The power transmission side resonator 2'also has the same configuration as the power transmission side resonator 2 and uses a coil 21 'and a capacitor 22' having the same values.

  A curve a in FIG. 5 shows a reflection coefficient (S11) when the power transmission side resonator 2 is excited by the transmission side controller 3 in the first simulation. It can be seen that the curve a has two valleys near 700 kHz, and thus has two resonance frequencies. The resonance mode of the resonance frequency on the left side of the curve a is an odd mode in which the electric fields generated from the coil 21 and the coil 21 'are in opposite phases, and the resonance mode of the resonance frequency on the right side is generated from the coil 21 and the coil 21'. It is an even mode in which the electric fields generated are in phase with each other. The resonance mode used in the first simulation is an odd mode.

  A curve b in FIG. 6 shows a change in the amount of electric field energy around the shield material 4 when the thickness T of the shield material 4 is changed. The vertical axis in FIG. 6 (and FIGS. 7 and 8 described later) is the electric field energy amount normalized by the magnetic field energy amount. The distance D between the water tank 6 and the shield material 4 was 5 mm. The conductivity of the water 41 of the shield material 4 was set to 0.02 S / m. In the curve b, the thicker the thickness T of the shield material 4, the greater the effect of shielding the electric field, and the smaller the amount of electric field energy outside the shield material 4. The electric field energy amount when the thickness T of the shield material 4 is 0 is the electric field energy amount when the shield material 4 is not provided.

  A curve c in FIG. 7 shows a change in the amount of electric field energy around the shield material 4 when the distance D between the water tank 6 and the shield material 4 is changed. The thickness T of the shield material 4 was 5 mm. The conductivity of the water 41 of the shield material 4 was set to 0.02 S / m. In the curve c, when the distance D is 5 mm, the electric field energy amount is larger than when the distance is 0, but when the distance D exceeds 5 mm, the electric field energy amount is gradually reduced. When the distance D is 15 mm to 20 mm or more, the amount of electric field energy is very small.

  A curve d in FIG. 8 shows a change in the amount of electric field energy around the shield material 4 when the conductivity of the water 41 of the shield material 4 is changed. The thickness T of the shield material 4 was 5 mm, and the distance D between the water tank 6 and the shield material 4 was 20 mm. It can be seen from the curve d that the electric field energy amount hardly changes depending on the conductivity.

  As a result of measuring tap water in 27 prefectures nationwide in Japan, the maximum electric conductivity is 0.06 S / m, and the electric conductivity of 0.02 S / m is the most easily available average value. Therefore, it is understood that tap water is usually used as the water 41 of the shield material 4.

  Next, the second simulation will be described. In the second simulation, the water tank 6 has a rectangular parallelepiped shape with a long side of 22 cm, a short side of 14 cm, and a height of 16 cm. In the second simulation, the shield material 4 is arranged on the side surface of the short side of the water tank 6 (see FIG. 9A) or on the upper surface side of the water tank 6 (see FIG. 9B), and the shield material 4 is formed. The electric field distribution was compared with that without. The distance from the water tank 6 to the shield material 4 was 1.8 cm. The shield member 4 is a plate-shaped member, and has a total thickness of 20 mm and the case 42 has a thickness of 5 mm. The conductivity of water 41 was 0.02 S / m. When the shield material 4 is arranged on the side of the short side of the water tank 6, the shield material 4 has a long side of 24.1 cm and a short side of 19 cm, and the shield material 4 is arranged on the upper surface side of the water tank 6. Has a long side of 35 cm and a short side of 19 cm.

  The coil 21 of the power transmission side resonator 2 was formed by winding an electric conductor wire having a diameter of 1 mm in a rectangular shape around the bottom surface of the water tank 6 to obtain 9 turns. A 238 pF or 23 nF capacitor 22 was connected to the coil 21 so that the resonance frequency was around 3 MHz or around 300 kHz. The power transmission side resonator 2'also has the same configuration as the power transmission side resonator 2 and uses a coil 21 'and a capacitor 22' having the same values. The resonance mode used in the second simulation is an odd mode as in the first simulation.

  Curves e and f in FIG. 10 show the reflection coefficient (S11) when the power transmitter resonator 2 is excited by the transmitter controller 3 in the second simulation. Curve e is for the capacitor 22 (and 22 ') of 238 pF in the second simulation, and curve f is for the capacitor 22 (and 22') of 23 nF in the second simulation. The curves g and h will be described later.

  FIG. 11 is a diagram showing an electric field distribution when the shield material 4 is arranged on the side surface of the short side of the water tank 6 in the second simulation, in which (a) is a resonance frequency near 3 MHz and (b) is The resonance frequency is around 300 kHz. FIG. 12 is a diagram showing an electric field distribution when the shield material 4 is arranged on the upper surface side of the water tank 6 in the second simulation, in which (a) is a resonance frequency near 3 MHz and (b) is a resonance frequency of 300 kHz. It is in the vicinity. FIG. 13 is a diagram showing an electric field distribution when the shield member 4 is not arranged near the water tank 6 in the second simulation, where (a) shows a resonance frequency near 3 MHz and (b) shows a resonance frequency near 300 kHz. belongs to. In these figures, the electric field strength in the whitest area is 10000 V / m or more, and the electric field strength in the blackest area is 1 V / m or less, and the brightness is logarithmically divided into 10 steps from the whitest to the blackest. ing.

  The electric field distributions of FIGS. 11A and 12A are compared with the electric field distribution of FIG. 13A, and the electric field distributions of FIGS. 11B and 12B are compared with the electric field distribution of FIG. 13B. Comparing with, it can be seen that the shield material 4 can provide a large shield effect against an electric field regardless of whether the resonance frequency is near 3 MHz or around 300 kHz. Since the electric field strength in the gap between the water tank 6 and the shield material 4 tends to be stronger, it is considered that the shield material 4 largely attenuates the electric field and also reflects the electric field at the interface before that. To be

  Next, the experiment will be described. In the experiment, the water tank 6, the power transmission side resonator 2, the power transmission side resonator 2 ′, and the shield material 4 having the same shape and size as those in the second simulation were used. In the experiment, the shield material 4 is arranged on the side surface of the short side of the water tank 6 (see FIG. 9A) or on the upper surface side of the water tank 6 (see FIG. 9B) so that the shield material 4 is located outside the shield material 4. The electric field strength was measured. Further, the shield material 4 was placed on the upper surface side of the water tank 6 (see FIG. 9B), and the magnetic field strength was measured. For the measurement of electric field strength and magnetic field strength in the experiment, Narda S. et al. T. S. EHP-200 manufactured by the company was used. Further, the distance from the water tank 6 to the shield material 4 was 1.8 cm. Therefore, since the thickness of the shield material 4 is 2 cm, the measurement of the electric field strength and the magnetic field strength starts at a point 3.8 cm from the water tank 6.

  The curves g and h in FIG. 10 described above show the reflection coefficient (S11) when the power transmission side resonator 2 is excited by the transmission side controller 3 in the experiment. The curve g is the one in which the capacitor 22 (and 22 ') is 238 pF in the experiment, and the curve h is the one in which the capacitor 22 (and 22') is 23 nF in the experiment. The curve g is in good agreement with the above-mentioned curve e, and the curve h is in good agreement with the above-mentioned curve f. The resonance mode used in the experiment is an odd mode as in the first simulation (and the second simulation).

  A curve i in FIG. 14 (a) and a curve i ′ in FIG. 14 (b) are diagrams showing electric field strength outside the shield material 4 when the shield material 4 is arranged on the side surface side of the short side of the water tank in the experiment. is there. FIG. 14A shows the resonance frequency near 3 MHz, and FIG. 14B shows the resonance frequency near 300 kHz. For comparison, FIGS. 14A and 14B also show a curve j and a curve j ′ of the electric field strength when the shield material 4 is removed. A curve k in FIG. 15 (a) and a curve k ′ in FIG. 15 (b) are diagrams showing electric field strength outside (upper side) the shield material 4 when the shield material 4 is arranged on the upper surface side of the water tank in the experiment. is there. FIG. 15A shows the resonance frequency near 3 MHz, and FIG. 15B shows the resonance frequency near 300 kHz. For comparison, FIGS. 15A and 15B also show a curve 1 and a curve 1 ′ of the electric field strength when the shield material 4 is removed.

  From these figures, even if the resonance frequency is in the vicinity of 3 MHz or in the vicinity of 300 kHz, when the shield material 4 is provided, the electric field strength is surely greatly reduced outside the shield material 4, and the shield material 4 generates an electric field. It can be seen that a large shield effect can be obtained.

  A curve m in FIG. 16 (a) and a curve m ′ in FIG. 16 (b) are diagrams showing the magnetic field strength outside (upper side) the shield material 4 when the shield material 4 is arranged on the upper surface side of the water tank in the experiment. is there. FIG. 16 (a) shows a resonance frequency near 3 MHz, and FIG. 16 (b) shows a resonance frequency near 300 kHz. For comparison, FIGS. 16A and 16B also show a magnetic field strength curve n and a curve n ′ when the shield material 4 is removed, respectively.

  16A and 16B, the curve m almost overlaps the curve n and the curve m ′ almost overlaps the curve n ′. Therefore, it can be seen that the shield material 4 has almost no effect on the magnetic field strength regardless of whether the resonance frequency is near 3 MHz or around 300 kHz.

  Although the wireless power supply device according to the embodiment of the present invention has been described above, the present invention is not limited to the one described in the above embodiment, and various modifications are possible within the scope of the matters described in the claims. Design changes are possible.

1 Wireless Power Supply Device 2, 2'Transmission Side Resonator 21, 21 'Coil 22, 22' Capacitor 3 Transmission Side Controller 3a High Frequency Power Supply 3b Coupling Loop 4 Shielding Material 41 Water 42 Case 5 Swimming Bodies Viewing Device 6 Water Tank 7 Swimming Body (power receiving device)
71 Power receiving side resonator

Claims (2)

At least one power-transmitting-side resonator having a coil;
A transmitter controller that controls the excitation of the at least one power transmitter resonator;
Water is stored and is arranged around the coil of the at least one power-transmitting-side resonator to shield the electric field of the non-radiated electromagnetic field from the coil;
A wireless power supply device comprising: The wireless power supply apparatus according to claim 1,
The wireless power supply device, wherein the water is tap water.