JP2017204938A - Wireless power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless power supply device without hiding its inside and including a shield material not requiring grounding.SOLUTION: A wireless power supply device 1 includes: at least one power transmission side resonator 2 including a coil; a transmission side controller 3 for controlling excitation of the at least one power transmission side resonator 2; and a shied material 4 that stores water 41, is placed around a coil 21 of the at least one power transmission side resonator 2, and shields an electric field of a non-radiation electromagnetic field from the coil 21.SELECTED DRAWING: Figure 1

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, 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. It is possible to supply power with high transmission efficiency with a simple configuration.

  In Patent Documents 1 to 3, 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 therein. 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, it is possible to further increase the transmission efficiency and supply power to the power receiving side device.

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

  Patent Document 3 discloses a swimming body appreciation device to which a coupled resonator type wireless power supply system is applied. In this swimming body appreciation device, power is transmitted wirelessly from a power transmission side device attached to the water tank to a swimming body that is a power reception 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 influence on the human body, although the long-term influence on the human body is unclear. As a countermeasure for this, it is conceivable that a shielding material for shielding the non-radiated electromagnetic field is arranged at an appropriate location around the power transmission side device so that the non-radiated electromagnetic field on the outer side becomes small. As the shielding material, a metal plate is typically considered, but the metal plate hides the inside thereof and must be grounded.

  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, without concealing the inside and without grounding. The object is to provide a good shield material.

  In order to achieve the above object, a wireless power supply device according to claim 1 includes: at least one power transmission side resonator having a coil; and transmission side control for controlling excitation of the at least one power transmission side resonator. And a shield material that stores water and is disposed around the coil of the at least one power transmission resonator to shield an electric field of a non-radiated electromagnetic field from the coil. It 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 device of the present invention, it is possible to prevent the shield material used therein from being grounded without concealing the inside thereof.

It is side surface sectional drawing which shows the structure of the wireless power supply apparatus which concerns on embodiment of this invention. It is a top view which shows the power transmission side resonator of a wireless power supply apparatus same as the above, Comprising: (a) is a coil circular shape, (b) is a coil rectangular shape. It is side view sectional drawing which shows the swimming body appreciation apparatus to which a wireless power supply apparatus same as the above is applied, (a) has one power transmission side resonator, (b) has two power transmission side resonators Is. It is a figure which shows the structure of a 1st simulation, Comprising: (a) is 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 electric field energy amount when changing the thickness of a shielding 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 shielding material in a 1st simulation. It is a characteristic view which shows the change of the electric field energy amount when changing the electrical conductivity of the water of a shielding material in a 1st simulation. It is side view which shows the structure of 2nd simulation, Comprising: (a) has arrange | positioned the shielding material on the side surface of the short side of a water tank, (b) has arrange | positioned the shielding material on 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 an electric field distribution when a shielding material is arrange | positioned in the 2nd simulation at the side surface of the short side of a water tank, Comprising: (a) The thing of resonance frequency 3MHz vicinity, (b) The thing of resonance frequency 300kHz vicinity It is. It is a figure which shows electric field distribution when a shielding material is arrange | positioned in the 2nd simulation on the upper surface side of a water tank, Comprising: (a) is the thing of resonance frequency 3MHz vicinity, (b) is the thing of resonance frequency 300kHz vicinity. It is a figure which shows the electric field distribution when not arrange | positioning a shielding material in the vicinity of a water tank in 2nd simulation, Comprising: (a) is the thing of resonance frequency 3MHz vicinity, (b) is the thing of resonance frequency 300kHz vicinity. It is a figure which shows the electric field strength outside a shielding material when a shielding material is arrange | positioned in the side surface of the short side of a water tank in experiment, (a) is near the resonant frequency of 3 MHz, (b) is near the resonant frequency of 300 kHz. belongs to. It is a figure which shows the electric field strength outside a shield material when a shield material is arrange | positioned in the upper surface side of a water tank in experiment, (a) is the thing near resonance frequency 3MHz, (b) is the thing near resonance frequency 300kHz. is there. It is a figure which shows the magnetic field intensity outside a shield material when a shield material is arrange | positioned in the upper surface side of a water tank in experiment, (a) is near the resonant frequency of 3 MHz, (b) is near the resonant frequency of 300 kHz. is there.

  Hereinafter, embodiments 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.

  As shown in FIGS. 2A and 2B, the power transmission side resonator 2 has a coil 21. The coil 21 may be a spiral coil in which an electrical conductor covered with an insulating film is spirally wound in a planar manner. The coil 21 has a circular shape as shown in FIG. 2 (a), a rectangular shape as shown in FIG. 2 (b), or other polygonal shape (for example, a hexagonal shape) or a more complicated shape. Can be rolled up. In addition, the coil 21 can be connected to a capacitor 22 between both ends (inner end and outer end) to adjust the resonance frequency. The coil 21 may be a solenoid coil in which an electrical conductor 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. In detail, the transmission-side controller 3 includes a high-frequency power source 3a and a coupling loop 3b (see FIG. 1). The high frequency power source 3a excites the power transmission side resonator 2 via a coupling loop 3b that performs impedance conversion. That is, the high frequency power supply 3 a outputs the output signal to the coupling loop 3 b, and the coupling loop 3 b is electromagnetically coupled to the coil 21 of the power transmission side resonator 2. The coupling loop 3b can be deformed or replaced with other known impedance converting means.

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

  The shield material 4 stores water 41. More specifically, the shielding material 4 may be configured to enclose water 41 in a case 42 made of transparent resin (for example, acrylic resin). Further, the shield material 4 is disposed in a part around the coil 21 of the power transmission side resonator 2. In FIG. 1, the shield material 4 is disposed on the right side of the coil 21, but any shape may be disposed in any place.

  The shield material 4 can shield the electric field of the non-radiated electromagnetic field from the coil 21 as shown in simulations and experiments to be described later. The shield material 4 has almost no influence on the magnetic field of the non-radiated electromagnetic field. The shield material 4 has almost no influence on the magnetic field of the non-radiated electromagnetic field, but can shield the electric field. Therefore, the amount of the total non-radiated electromagnetic field outside the shield material 4 (on the side opposite to the coil 21). Can be reduced. In addition, when a transparent case is used for the shield material 4, since water is also transparent, the inner side (coil 21 side) is not hidden, so that the inner side can be visually recognized from the outer side of the shield material 4. Also, 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 it can be freely placed in various places without considering grounding. Can do.

  The wireless power supply apparatus 1 having the configuration described above can be applied to various wireless power supply systems. For example, as shown to Fig.3 (a), it can use for the swimming body ornamental apparatus 5. FIG. In the swimming body appreciation 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. A 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 disposed on the side surface of the water tank 6 or the like.

  In the swimming body appreciation device 5, if the shield member 4 is arranged between the water tank 6 and the person who watches the inside of the water tank 6, the amount of non-radiated electromagnetic fields hitting the human body can be reduced without inhibiting the viewing. The shield material 4 can be freely arranged in a free shape.

  Moreover, in the swimming body appreciation device 5, 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, as shown in FIG. Can be provided. The power transmission side resonator 2 ′ has a coil 21 ′, and a capacitor 22 ′ can be connected between both ends (inner end and outer end) to adjust the resonance frequency.

  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 it, and generates a non-radiation electromagnetic field downward. . As a result, power is supplied to the power receiving side resonator 71 of the swimming body 7 not only by the non-radiating electromagnetic field from the power transmitting side resonator 2 but also by the non-radiating electromagnetic field from the power transmitting side resonator 2 ′. The power transmission side resonator 2 'operates only by itself, and no coupling loop or high frequency power source is provided for that purpose.

  Next, simulations and experiments performed on the wireless power supply apparatus 1 will be described. As the simulation software, HFSS manufactured by ANSYS 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 is provided at the bottom of the water tank 6, and the power transmission side resonator 2 ′ is provided at the lid of the water tank 6. Water was introduced into the water tank 6.

  First, the first simulation will be described. 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 material 4 (water 41) was formed in a cylindrical shape having a height of 10 cm so as to surround the side surface of the water tank 6 as shown in FIGS. Note that the thickness of the case 42 of the shield material 4 was set to zero. 4 (a) and 4 (b), a 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 integrates electric field energy or magnetic field energy. This is the range in which the electric field energy amount or magnetic field energy amount described later is derived.

  The coil 21 of the power transmission side resonator 2 was formed by winding a 1 mm diameter electric conducting wire in a circular shape and having 15 turns 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 ′ has the same configuration as that of the power transmission side resonator 2 and uses a coil 21 ′ and a capacitor 22 ′ having the same value.

  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 in the vicinity of 700 kHz, and thus has two resonance frequencies. The resonance mode of the resonance frequency on the left side in 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'. This is an even mode in which electric fields to be 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 FIG. 7 and FIG. 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 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 electric field energy amount outside the shield material 4. In addition, the electric field energy amount when the thickness T of the shield material 4 is 0 is an 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 0.02 S / m. In the curve c, the electric field energy amount is increased when the distance D is 5 mm than when the distance is 0, but the electric field energy amount is gradually decreased when the distance D exceeds 5 mm. If the distance D is 15 mm to 20 mm or more, the electric field energy amount 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, the maximum value of conductivity is 0.06 S / m, and the average value of conductivity 0.02 S / m is the most readily available. Therefore, it can be seen 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 shielding material 4 is disposed on the side surface of the short side of the water tank 6 (see FIG. 9A) or disposed on the upper surface side of the water tank 6 (see FIG. 9B), and the shielding material 4 The electric field distribution was compared with the one not arranged. The distance from the water tank 6 to the shield material 4 was 1.8 cm. The shield material 4 was plate-shaped, the total thickness was 20 mm, and the thickness of the case 42 was 5 mm. The conductivity of the water 41 was 0.02 S / m. When the shield material 4 is disposed on the side surface of the short side of the water tank 6, the shield material 4 having a long side of 24.1 cm and a short side of 19 cm is used, and the shield material 4 is disposed on the upper surface side of the water tank 6. Used were those having 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 conducting wire having a diameter of 1 mm around the periphery of the bottom surface of the water tank 6 in a rectangular shape with 9 turns. A 238 pF or 23 nF capacitor 22 was connected to the coil 21 so that the resonance frequency was close to 3 MHz or 300 kHz. The power transmission side resonator 2 ′ has the same configuration as that of the power transmission side resonator 2 and uses a coil 21 ′ and a capacitor 22 ′ having the same value. 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 transmission side resonator 2 is excited by the transmission side controller 3 in the second simulation. Curve e is for capacitor 22 (and 22 ') in the second simulation with 238 pF, and curve f is for capacitor 22 (and 22') in the second simulation with 23 nF. The curves g and h will be described later.

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

  11 (a) and 12 (a) is compared with the electric field distribution of FIG. 13 (a), and the electric field distributions of FIG. 11 (b) and FIG. 12 (b) are compared with the electric field distribution of FIG. 13 (b). As compared with the above, it can be seen that the shielding material 4 can provide a large shielding effect against the electric field regardless of whether the resonance frequency is around 3 MHz or around 300 kHz. In addition, since the electric field strength of the gap between the water tank 6 and the shield material 4 tends to increase, it is considered that the shield material 4 greatly attenuates the electric field and also reflects the electric field at the interface before that. It is done.

  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 disposed on the side surface of the short side of the water tank 6 (see FIG. 9A) or disposed on the upper surface side of the water tank 6 (see FIG. 9B). The electric field strength was measured. Moreover, the shielding material 4 was arrange | positioned on the upper surface side of the water tank 6 (refer FIG.9 (b)), and the magnetic field strength was measured. For the measurement of the electric field strength and magnetic field strength in the experiment, Narda S. T. T. S. EHP-200 made by company was used. 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 from a point of 3.8 cm from the water tank 6.

  The above-described curves g and h in FIG. 10 show the reflection coefficient (S11) when the power transmission side resonator 2 is excited by the transmission side controller 3 in the experiment. Curve g is the experiment with capacitor 22 (and 22 ') of 238 pF, and curve h is the experiment with capacitor 22 (and 22') of 23 nF. The curve g is in good agreement with the curve e described above, and the curve h is in good agreement with the curve f described above. 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. 14A and a curve i ′ in FIG. 14B are diagrams showing the electric field strength outside the shield material 4 when the shield material 4 is arranged on the side of the short side of the water tank in the experiment. is there. FIG. 14A shows the case where the resonance frequency is around 3 MHz, and FIG. 14B shows the case where the resonance frequency is around 300 kHz. FIGS. 14 (a) and 14 (b) also show electric field intensity curves j and j 'when the shield material 4 is removed for comparison. A curve k in FIG. 15A and a curve k ′ in FIG. 15B are diagrams showing the electric field strength outside (upper) 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 case where the resonance frequency is around 3 MHz, and FIG. 15B shows the case where the resonance frequency is around 300 kHz. FIG. 15A and FIG. 15B also show electric field intensity curves 1 and 1 'when the shield material 4 is removed for comparison.

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

  A curve m in FIG. 16A and a curve m ′ in FIG. 16B are diagrams showing the magnetic field strength outside (upper) 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. 16A shows the case where the resonance frequency is around 3 MHz and FIG. 16B shows the case where the resonance frequency is around 300 kHz. FIGS. 16A and 16B also show a magnetic field intensity curve n and a curve n ′ when the shield material 4 is removed, for comparison.

  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 hardly affects the magnetic field strength regardless of whether the resonance frequency is around 3 MHz or around 300 kHz.

  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.

DESCRIPTION OF SYMBOLS 1 Wireless power supply device 2, 2 'Power 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 body appreciation device 6 Aquarium 7 Swimming Body (power-receiving device)
71 Receiving side resonator

Claims (2)

At least one power transmission resonator having a coil;
A transmission side controller for controlling excitation of the at least one power transmission side resonator;
Water is stored, and a shielding material disposed around the coil of the at least one power transmission resonator to shield an electric field of a non-radiating electromagnetic field from the coil;
A wireless power supply device comprising: The wireless power supply device according to claim 1.
The wireless power supply device, wherein the water is tap water.