JP2016059145A - Wireless power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless power transmission device, capable of highly accurately controlling an electromagnetic field at a position of a power reception device even when a plurality of power transmission resonators are used therein.SOLUTION: A wireless power transmission device 1 includes: first and second power transmission resonators 2x, 2y spatially electromagnetic-field-coupled to each other; a power transmission controller 3 including high frequency power sources 31x, 31y and controlling the excitation of the first and second power transmission resonators 2x, 2y; and a coupling adjustment circuit 4 arranged between the first and second power transmission resonators 2x, 2y and canceling a part or the whole of the electromagnetic field coupling therebetween.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resonant coupling type wireless power transmission apparatus that performs wireless power transmission using non-radiated electromagnetic field coupling.

  2. Description of the Related Art Conventionally, a resonance-type wireless power transmission apparatus that performs wireless power transmission using non-radiated electromagnetic field coupling is known. The resonance-type wireless power transmission device has a power transmission resonator, and when the power reception device having the power reception resonator is within the power transmission range, the power transmission resonator and the power reception resonator are non-radiated electromagnetic fields, In other words, power is transmitted to the power receiving device by resonance coupling via a magnetic field or an electric field.

  Among these resonance-type wireless power transmission devices, one having a plurality of power transmission resonators is known. For example, in Patent Document 1, two power transmission resonators are arranged so as to be substantially orthogonal to each other, and are excited with a phase difference of 90 °, thereby rotating the direction of the electromagnetic field (particularly the magnetic field) with time. Thus, a wireless power transmission device that can stably transmit power to the power receiving device regardless of the direction of the power receiving device is described.

JP2013-247718A

  However, there is still room for development with respect to accurately controlling the direction of the electromagnetic field using a plurality of power transmission resonators. The inventors of the present application have devised a wireless power transmission device capable of accurately controlling the electromagnetic field at the position of the power receiving device, paying attention to mutual spatial electromagnetic field coupling of a plurality of power transmission resonators.

  The present invention has been made in view of the above-described reason, and an object thereof is a wireless power transmission device capable of accurately controlling an electromagnetic field at the position of a power receiving device even when a plurality of power transmission resonators are used. Is to provide.

  In order to achieve the above object, a wireless power transmission device according to claim 1 includes first and second power transmission resonators that are spatially electromagnetically coupled to each other, and at least one high-frequency power source. And a power transmission controller for controlling excitation of the first and second power transmission resonators, and the first and second power transmission resonators, and a part or all of the electromagnetic field coupling is provided. And a coupling adjustment circuit for canceling.

  The wireless power transmission device according to claim 2 is the wireless power transmission device according to claim 1, wherein the electromagnetic field coupling between the first power transmission resonator and the second power transmission resonator is coupled by a magnetic field. The coupling adjustment circuit includes a capacitor and cancels part or all of the coupling by the magnetic field of the electromagnetic field coupling by the capacitor.

  The wireless power transmission device according to claim 3 is the wireless power transmission device according to claim 1, wherein the electromagnetic field coupling between the first power transmission resonator and the second power transmission resonator is coupled by an electric field. The coupling adjustment circuit includes an inductor, and the inductor cancels part or all of the coupling by the electric field of the electromagnetic field coupling.

  The wireless power transmission device according to claim 4 is the wireless power transmission device according to any one of claims 1 to 3, wherein the coupling adjustment circuit includes a winding of the first power transmission resonator and the first power transmission resonator. It is provided so that it may connect directly with the winding of 2 power transmission resonators.

  The wireless power transmission device according to claim 5 is the wireless power transmission device according to any one of claims 1 to 4, wherein the coupling adjustment circuit is configured to have a variable circuit constant. To do.

  The wireless power transmission device according to claim 6 is the wireless power transmission device according to any one of claims 1 to 5, wherein the power transmission controller includes first and second high-frequency power supplies, Each of the first and second power transmission resonators is excited by the output signal.

  The wireless power transmission device according to claim 7 is the wireless power transmission device according to any one of claims 1 to 5, wherein the power transmission controller includes a high-frequency power source and a phaser for inputting an output signal thereof. And exciting one of the first and second power transmission resonators by the output signal of the high-frequency power source and the other of the first and second power transmission resonators by the output signal of the phase shifter. Features.

  According to the wireless power transmission device of the present invention, the electromagnetic field at the position of the power receiving device can be accurately controlled even if a plurality of power transmission resonators are used.

It is a block diagram which shows typically the structure of the wireless power transmission apparatus which concerns on embodiment of this invention. It is a wave form diagram of the 1st and 2nd excitation signal of a wireless power transmission apparatus same as the above. It is a block diagram which shows the modification of the power transmission controller of a wireless power transmission apparatus same as the above. It is a circuit diagram which shows an example of the coupling adjustment circuit of a wireless power transmission apparatus same as the above. It is a circuit diagram which shows the other examples of the coupling adjustment circuit of a wireless power transmission apparatus same as the above. It is a perspective view which shows typically the structure of the power receiving apparatus in which electric power is transmitted from a wireless power transmission apparatus same as the above. It is a schematic diagram of planar view which shows the mode of a magnetic field vector change of a wireless power transmission apparatus same as the above. It is a schematic diagram of planar view which shows arrangement | positioning of a receiving resonator with respect to a wireless power transmission apparatus same as the above. It is a characteristic view which shows the transmission efficiency of a wireless power transmission apparatus same as the above. It is a block diagram which shows typically the modification of the wireless power transmission apparatus same as the above.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. As shown in FIG. 1, the wireless power transmission device 1 according to the embodiment of the present invention includes a first power transmission resonator 2x, a second power transmission resonator 2y, a power transmission controller 3, and a coupling adjustment circuit 4. doing. When the power receiving device 5 is within the power transmission range, the wireless power transmission device 1 can transmit power to the power receiving device 5 by a resonance type coupling method.

  The first and second power transmission resonators 2x and 2y are spatially electromagnetically coupled to each other. The first and second power transmission resonators 2 x and 2 y are excited by the power transmission controller 3. In this embodiment, the first and second power transmission resonators 2x and 2y are arranged so as to be substantially orthogonal to each other, and excited by the power transmission controller 3 with a phase difference of 90 ° as shown in FIG. ing. The shapes of the first and second power transmission resonators 2x and 2y are not limited. For example, the windings 20x and 20y as shown in FIG. 1 are formed to be planar and spirally wound. It is possible to use a spiral coil. In FIG. 1, one end (inner end) and the other end (outer end) of the windings 20x and 20y are connected by wiring, but the one end and the other end are opened or connected by wiring via a capacitor. You may connect.

  The power transmission controller 3 controls the excitation of the first and second power transmission resonators 2x and 2y. Specifically, the power transmission controller 3 includes first and second high-frequency power sources 31x and 31y, and the output loops (first and second excitation signals) Vx and Vy cause the coupling loops 32x and 32y to be connected. The first and second power transmission resonators 2x and 2y are each excited. The coupling loops 32x and 32y are electromagnetically coupled to the first and second power transmission resonators 2x and 2y, respectively, and perform impedance matching. The coupling loops 32x and 32y can be replaced with other known impedance matching means.

  As shown in FIG. 3, the power transmission controller 3 includes a high-frequency power supply 31 and a phase shifter 33 for inputting the output signal Vx thereof. The first power transmission resonator 2x is connected to the phase shifter by the output signal Vx of the high-frequency power supply 31. It is also possible to excite the second power transmission resonator 2y by the 33 output signal Vy.

  The coupling adjustment circuit 4 is provided between the first and second power transmission resonators 2x and 2y. The coupling adjustment circuit 4 cancels (cancels) part or all of the spatial electromagnetic field coupling of the first and second power transmission resonators 2x and 2y. The coupling adjustment circuit 4 can be directly connected to the winding 20x of the first power transmission resonator 2x and the winding 20y of the second power transmission resonator 2y.

  4 and 5 show an equivalent circuit and a coupling adjustment circuit 4 of the first and second power transmission resonators 2x and 2y. An equivalent circuit of the first power transmission resonator 2x is obtained by connecting an inductance component 21x, a capacitance component 22x, and a resistance component 23x in series. An equivalent circuit of the second power transmission resonator 2y is an inductance component 21y and a capacitance component 22y. And the resistance component 23y are connected in series. The electromagnetic field coupling of the first and second power transmission resonators 2x and 2y includes coupling by a magnetic field and coupling by an electric field. Since the coupling value by the magnetic field and the coupling by the electric field are opposite to each other, the difference is an actual amount of electromagnetic field coupling between the first and second power transmission resonators 2x and 2y. When the coupling by the magnetic field is larger than the coupling by the electric field, the coupling by the magnetic field is dominant, and when the coupling by the electric field is larger than the coupling by the magnetic field, the coupling by the electric field is dominant. Depending on the mutual positional relationship between the first and second power transmission resonators 2x and 2y, a case where the coupling by the magnetic field is dominant and a case where the coupling by the electric field is dominant may occur.

  When the coupling by the magnetic field is dominant, that is, when the coupling by the magnetic field is larger than the coupling by the electric field, as shown in FIG. 4, in the equivalent circuit, the inductance component 21x of the first power transmission resonator 2x and the second component A mutual inductance M is generated between the inductance components 21y of the power transmission resonator 2y. In this case, a part or all of the electromagnetic field coupling can be canceled by using the coupling adjustment circuit 4 as a capacitance and performing parallel resonance with the inductance generated by the electromagnetic field coupling, that is, the mutual inductance M. The coupling adjustment circuit 4 may have variable circuit constants.

  On the contrary, when the coupling by the electric field is dominant, that is, when the coupling by the electric field is larger than the coupling by the magnetic field, as shown in FIG. 5, in the equivalent circuit, the first power transmission resonator 2x and the second power transmission There is a capacitance component 24 between the resonators 2y. In this case, by using the coupling adjustment circuit 4 as an inductor, the capacitance generated by the electromagnetic field coupling, that is, the capacitance component 24 can be caused to resonate in parallel, so that part or all of the electromagnetic field coupling can be canceled. The coupling adjustment circuit 4 may have variable circuit constants.

  The power receiving device 5 can include a power receiving resonator 6 and a load circuit 7 as shown in FIG.

  The power receiving resonator 6 has its resonance frequency matched with the resonance frequencies of the first and second power transmission resonators 2x and 2y. The shape of the power receiving resonator 6 is not limited. For example, the power receiving resonator 6 may be a spiral coil formed by winding the winding 60 in a planar and spiral shape. In FIG. 6, one end (inner end) and the other end (outer end) of the winding 60 are connected by wiring, but one end and the other end are opened or connected by wiring through a capacitor. Or you may.

  The load circuit 7 is coupled to the power receiving resonator 6. Specifically, the load circuit 7 includes a coupling loop 71 and a load 72. The coupling loop 71 is electromagnetically coupled to the power receiving resonator 6 and performs impedance matching. Power is supplied to the load 72 from the power receiving resonator 6 through the coupling loop 71. The load 72 is a circuit for exhibiting a required function of a device such as a communication terminal. The coupling loop 71 can be replaced with other known impedance matching means.

  In the wireless power transmission device 1 having such a configuration, the power transmission controller 3 excites the first and second power transmission resonators 2x and 2y, and the first and second power transmission resonators 2x and 2y are constant around each other. A non-radiating electromagnetic field is generated independently of the range (power transmission range). This non-radiated electromagnetic field is a combination of the non-radiated electromagnetic field generated by the first power transmission resonator 2x and the non-radiated electromagnetic field generated by the second power transmission resonator 2y. When the power receiving device 5 is within the power transmission range, power transmission from the first and second power transmission resonators 2x and 2y to the power receiving device 5 is independent from each other, and isolation from the first power transmission resonator 2x. Power transmission is not transmitted to the power receiving device 5 via the second power transmission resonator 2y, and power transmission from the second power transmission resonator 2y is not transmitted to the power receiving device 5 via the first power transmission resonator 2x. It becomes like this.

  In this embodiment, the first and second power transmission resonators 2x and 2y are arranged so as to be substantially orthogonal to each other and are excited with a phase difference of 90 °. The combined magnetic and electric fields of the resonators 2x and 2y rotate with time. For example, the magnetic field rotates as shown in FIG. The position of the point indicating the magnetic field vector in the figure is near the intersection of the center lines of the first and second power transmission resonators 2x and 2y. In the figure, when the phase of the first excitation signal Vx is 0 ° (when the phase of the second excitation signal Vy is −90 °), the vector A, and when the phase of the first excitation signal Vx is 45 ° Vector B (when the phase of the second excitation signal Vy is −45 °), vector vector when the phase of the first excitation signal Vx is 90 ° (when the phase of the second excitation signal Vy is 0 °) C, vector D when the phase of the first excitation signal Vx is 135 ° (when the phase of the second excitation signal Vy is 45 °), and when the phase of the first excitation signal Vx is 180 ° (second Vector E when the phase of the first excitation signal Vy is 90 °), vector F when the phase of the first excitation signal Vx is 225 ° (when the phase of the second excitation signal Vy is 135 °), and the first When the phase of the excitation signal Vx is 270 ° (when the phase of the second excitation signal Vy is 180 °) Torr G and vector H are shown when the phase of first excitation signal Vx is 315 ° (when the phase of second excitation signal Vy is 225 °). In this way, the magnetic field rotates according to the first and second excitation signals Vx and Vy of the power transmission controller 3. Similarly, the electric field rotates according to the first and second excitation signals Vx and Vy of the power transmission controller 3.

  If the magnetic field or electric field vector can be rotated with high accuracy in this way, as shown in FIG. 8, the power receiving device 5 within the power transmission range around the first and second power transmission resonators 2x and 2y, That is, when the power receiving resonator 6 is arranged, power is transmitted to the power receiving device 5 with stable transmission efficiency regardless of the direction of the power receiving device 5.

  FIG. 9 is an experimental result showing a change in transmission efficiency with respect to the rotation angle θ in the direction of the power receiving resonator 6. The curve a indicates the distance d between the first power transmission resonator 2x and the power reception resonator 6 and the distance d ′ between the second power transmission resonator 2y and the power reception resonator 6 using the wireless power transmission device 1. This is an actual measurement value when the diameter of the first and second power transmission resonators 2x and 2y is 50 cm and the diameter of the power reception resonator 6 is 5 cm. On the other hand, the curve b is an actual measurement value when the second power transmission resonator 2y is omitted under the above-described conditions. From the curve a, it can be seen that when the wireless power transmission device 1 is used, even if the rotation angle θ in the direction of the power receiving resonator 6 is changed, the change in transmission efficiency is very small. That is, it can be seen that power is transmitted to the power receiving device 5 with stable transmission efficiency regardless of the direction of the power receiving device 5.

  The wireless power transmission device 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 wireless power transmission device of the present invention is not limited to the one in which the combined electromagnetic field (magnetic field or electric field) rotates, but can be applied to various cases in which the electromagnetic field at the position of the power receiving device is accurately controlled. In this case, the first power transmission resonator 2x and the second power transmission resonator 2y may be arranged at various angles without being substantially orthogonal, the excitation phase difference is not limited to 90 °, and the phase difference is further increased. There is a case where it is not necessary to attach it.

  Further, the power receiving device 5 is not limited to one and may be plural. In addition to the first and second power transmission resonators 2x and 2y, a power transmission resonator may be provided. For example, FIG. 10 is an example in which a third power transmission resonator 2z substantially orthogonal to each of the first and second power transmission resonators 2x and 2y is provided. The third power transmission resonator 2z is excited through the coupling loop 32z by the output signal of the third high frequency power supply 31z. The coupling adjustment circuit 4 ′ is provided between the first and third power transmission resonators 2x and 2z, and the coupling adjustment circuit 4 ″ is provided between the second and third power transmission resonators 2y and 2z. .

DESCRIPTION OF SYMBOLS 1 Wireless power transmission apparatus 2x, 2y Power transmission resonator 3 Power transmission controller 31, 31x, 31y High frequency power supply 32x, 32y Coupling loop 33 Phase shifter 4 Coupling adjustment circuit 5 Power receiving apparatus 6 Power receiving resonator 7 Load circuit 71 Coupling loop 72 Load

Claims (7)

First and second power transmission resonators spatially electromagnetically coupled to each other;
A power transmission controller having at least one high-frequency power source and controlling excitation of the first and second power transmission resonators;
A coupling adjustment circuit that is provided between the first and second power transmission resonators and cancels part or all of the electromagnetic field coupling;
A wireless power transmission device comprising: The wireless power transmission device according to claim 1,
The electromagnetic coupling between the first power transmission resonator and the second power transmission resonator is such that the coupling by the magnetic field is larger than the coupling by the electric field,
The wireless power transmission apparatus according to claim 1, wherein the coupling adjustment circuit includes a capacitor, and the capacitor cancels part or all of the coupling by the magnetic field of the electromagnetic field coupling. The wireless power transmission device according to claim 1,
The electromagnetic field coupling between the first power transmission resonator and the second power transmission resonator is such that coupling by an electric field is larger than coupling by a magnetic field,
The coupling adjustment circuit includes an inductor, and the inductor cancels a part or all of the coupling due to the electric field of the electromagnetic field coupling. In the wireless power transmission device according to any one of claims 1 to 3,
The wireless power transmission device according to claim 1, wherein the coupling adjustment circuit is provided so as to be directly connected to a winding of the first power transmission resonator and a winding of the second power transmission resonator. In the wireless power transmission device according to any one of claims 1 to 4,
The wireless power transmission apparatus according to claim 1, wherein the coupling adjustment circuit has a configuration in which a circuit constant is variable. In the wireless power transmission device according to any one of claims 1 to 5,
The power transmission controller includes first and second high-frequency power supplies, and each of the first and second power transmission resonators is excited by these output signals. In the wireless power transmission device according to any one of claims 1 to 5,
The power transmission controller includes a high-frequency power source and a phaser that inputs an output signal thereof, and outputs one of the first and second power transmission resonators according to the output signal of the high-frequency power source as an output signal of the phaser. A wireless power transmission device that excites the other of the first and second power transmission resonators.

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