Contactless power supply system

Abstract

To provide a contactless power supply system that uses a single power supply to generate and feed a rotating magnetic field by a combination of coils.SOLUTION: A contactless power supply system 100 includes a single AC power supply 10, a power transmission coil 20 connected to the single AC power supply, four relay coils 30 (30-1 to 30-4) magnetically coupled to the power transmission coil 20, and a receiving coil 40 (see FIG. 3) magnetically coupled to the relay coils 30. The impedance of the four relay coils 30 is adjusted such that a synthetic magnetic field generated by the four relay coils 30 when an alternating current flows through the power transmission coil 20 generates a rotating magnetic field.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a contactless power supply system. [Background technology]

[0002] Contactless power transfer technology, which transmits power without contact, has already been put to practical use in mobile phone terminals and other home appliances. In magnetically coupled contactless power transfer systems, power is transferred by coupling the power transmitting coil of a power transmitting device and the power receiving coil of a power receiving device using a magnetic field. Known magnetically coupled contactless power transfer methods include the electromagnetic induction method and the magnetic resonance method. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 150678 Summary of the Invention [Problem to be solved by the invention]

[0004] In the electromagnetic induction method, high-efficiency power transfer is possible when the coupling between the power transmitting coil and the power receiving coil is very strong. However, maintaining high efficiency requires a high coupling coefficient between the power transmitting coil and the power receiving coil. Therefore, if the power transmitting coil and the power receiving coil are farther apart or misaligned, the power transfer efficiency between the transmitting and receiving coils drops significantly. On the other hand, the magnetic resonance method has the advantage that even if the coupling coefficient between the power transmitting coil and the power receiving coil is small, the inter-coil efficiency does not decrease as long as the quality factor (Q) is high, so there is a high degree of freedom in the position and distance of the power transmitting coil and the power receiving coil. The Q factor is an index that represents the relationship between energy retention and loss in a circuit containing a power transmitting or receiving coil (indicating the strength of resonance in a resonant circuit).

[0005] While studying the power transmission efficiency of omnidirectional power transmission using a cubic power transmission coil in a magnetic field coupling type contactless power supply system, the inventors discovered that when a single power source is used, the power transmission efficiency drops significantly depending on the angle between the transmitting and receiving coils.

[0006] Figure 14(a) is a schematic diagram of a square transmitting coil created in one stroke using a single wire, and Figure 14(b) is a schematic diagram of a square transmitting coil with four coils connected in parallel.We connected a single power supply to the transmitting coils shown in Figures 14(a) and 14(b), changed the angle between the transmitting coil and receiving coil, and used a square receiving coil to calculate the efficiency using numerical electromagnetic field analysis. Fig. 15 is a schematic diagram showing the arrangement of the power transmitting and receiving coils as viewed from above the power transmitting coil, in order to show the angle between them. The angle at which the power receiving coil is arranged parallel to the square power transmitting coil is set to 0 degrees. Figs. 16(a) and 16(b) show the results of calculations of the power efficiency between power transmitting and receiving when this angle is changed between 0 and 45 degrees.

[0007] Power transmission efficiency η max was calculated using the following formula:

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[0008] When the power transmitting coil of FIG. 14(a) was used, as shown in FIG. 16(a), the efficiency did not change much with changes in the coil angle between the power transmitting and receiving sides, but the efficiency was low overall. On the other hand, when the four-coil parallel transmitting coil of Fig. 14(b) was used, as shown in Fig. 16(b), the efficiency was higher than that of the transmitting coil of Fig. 14(a) at angles between 0 and 30 degrees, but the efficiency changed significantly depending on the coil angle between the transmitting and receiving coils. This result is thought to be because when a single power supply is used, there is only one current phase and the magnetic field does not rotate, so the power transmission efficiency changes depending on the angle between the transmitting and receiving coils.

[0009] The present invention has been made in view of the above circumstances, and has an object to provide a contactless power supply system that uses a single power source and generates a rotating magnetic field by combining coils to supply power. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides the following means.

[0011] A contactless power supply system according to a first aspect of the present invention includes a single AC power source, a power transmission coil connected to the single AC power source, a plurality of relay coils magnetically coupled to the power transmission coil, and a power receiving coil magnetically coupled to the relay coil, wherein the impedances of the plurality of relay coils are adjusted so that a composite magnetic field generated by the plurality of relay coils generates a rotating magnetic field when an AC current flows through the power transmission coil.

[0012] In the contactless power supply system according to the above aspect, the plurality of relay coils may be arranged around the power transmission coil so as to surround the power transmission coil when viewed from a normal direction of the power transmission coil.

[0013] In the contactless power supply system according to the above aspect, the multiple relay coils may be arranged around the power transmission coil at positions of 360 degrees / n (n is an integer) relative to the power transmission coil when viewed from a normal direction of the power transmission coil.

[0014] In the contactless power supply system according to the above aspect, the plurality of relay coils may be arranged with respect to the power transmission coil such that normal directions of all of the relay coils intersect with a normal direction of the power transmission coil at an angle.

[0015] In the contactless power supply system according to the above aspect, the plurality of relay coils may be arranged with respect to the power transmission coil such that the normal directions of all of the relay coils form approximately 90 degrees with respect to the normal direction of the power transmission coil.

[0016] In the contactless power supply system according to the above aspect, the plurality of relay coils may be arranged around the power transmission coil so as to surround the power transmission coil when viewed from a normal direction of the power transmission coil, and at least some adjacent relay coil groups among the plurality of relay coils may be arranged alternately so as to sandwich the power transmission coil when viewed from a direction perpendicular to the normal direction of the power transmission coil.

[0017] In the contactless power supply system according to the above aspect, at least some of the relay coils may have a bent portion that corresponds to a shape of a bent portion of the power transmission coil.

[0018] In the contactless power supply system according to the above aspect, the plurality of relay coils may have different current phases.

[0019] The contactless power supply system according to the above aspect may further include a relay coil having a normal direction that is the same as a normal direction of the power transmission coil.

[0020] The contactless power supply system according to the above aspect may further include a vertical magnetic flux generating relay coil having a normal direction different from a normal direction of the plurality of relay coils and generating a magnetic field orthogonal to a composite magnetic field generated by the plurality of relay coils.

[0021] In the contactless power supply system according to the above aspect, the vertical magnetic flux generating relay coil may be a relay coil having a normal direction that is the same as a normal direction of the power transmission coil. [Effects of the Invention]

[0022] According to the contactless power supply system of the present invention, it is possible to provide a contactless power supply system that uses a single power source and generates a rotating magnetic field by combining coils to supply power. [Brief explanation of the drawings]

[0023] [Figure 1]1 is a circuit diagram showing an outline of a contactless power supply system according to an embodiment of the present invention, which generates a rotating magnetic field using four relay coils with a single power supply. [Figure 2] FIG. 10 is a phasor diagram of impedance in four relay coils. [Figure 3] FIG. 2 is a diagram showing an actual coil arrangement of the contactless power supply system shown in the circuit diagram of FIG. [Figure 4] 1 is a circuit diagram showing an outline of a contactless power supply system according to the present embodiment, which generates a rotating magnetic field using six relay coils with a single power supply. [Figure 5] (a) Phasor diagram of impedance in six repeater coils. (b) Phasor diagram of admittance and current in six repeater coils. [Figure 6] FIG. 5 shows the actual coil layout of the contactless power transfer system shown in the circuit diagram of FIG. 4, the positional relationship between six relay circuits and a power receiving circuit, and the respective circuit diagrams. [Figure 7] FIG. 1 is a circuit diagram showing an outline of a contactless power supply system according to the present embodiment, which generates a rotating magnetic field using eight relay coils with a single power supply. [Figure 8] 1A is an example of a phasor diagram of impedance in four repeater coils; FIG. 1B is another example of a phasor diagram of impedance in four repeater coils; [Figure 9] (a) A diagram showing the actual coil layout of the contactless power transfer system shown in the circuit diagram of Fig. 7, the positional relationship between eight relay circuits and a power receiving circuit, and the respective circuit diagrams. (b) A diagram showing the layout of three relay coils. (c) A diagram showing the shape of the relay coils as seen from above. (d) A diagram showing the shape of the relay coils as seen from diagonally above. [Figure 10] 10A and 10B are diagrams for explaining a decrease in efficiency when the power receiving coil is placed horizontally. [Figure 11] This is a diagram of a contactless power transfer system in which four relay coils for generating vertical magnetic flux are added to the coil arrangement shown in Figure 3 and are arranged horizontally in the same plane as the power transmission coil. [Figure 12]This is a diagram of a contactless power transfer system in which six relay coils for generating vertical magnetic flux are added to the coil arrangement shown in Figure 6 and are arranged horizontally in the same plane as the power transmission coil. [Figure 13] 13 is a diagram schematically illustrating a magnetic field generated in the vicinity of a configuration in which a vertical magnetic flux generation relay coil is added to the vertical magnetic flux generation relay coil 30VV shown in FIG. 12. FIG. [Figure 14] (a) Schematic diagram of a square transmitter coil made with a single wire. (b) Schematic diagram of a square transmitter coil with four coils connected in parallel. [Figure 15] FIG. 2 is a schematic diagram showing the arrangement of the power transmitting and receiving coils as viewed from above the power transmitting coil. [Figure 16] 14(a) and 14(b) are graphs showing the power transmission efficiency versus the power transmission and reception angle in the power transmitting and receiving coils shown in FIG. 14(a) and FIG. 14(b), respectively. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be described in detail below with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for the sake of clarity, and the dimensional proportions of each component may differ from the actual dimensions. The dimensions and other details exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate changes can be made within the scope of the effects of the present invention.

[0025] Figure 1 shows a schematic diagram of a contactless power transfer system according to this embodiment. The configuration shown in the figure is an example in which a rotating magnetic field is generated using four relay coils. Although Figure 1 shows a two-dimensional diagram for the purpose of explanation, in reality, the relay coils and the power transmission coil are arranged perpendicular to each other (see Figure 3). In Figure 1, the symbol representing electric current has a "dot" attached to it to indicate that it is a vector quantity having a magnitude and a phase, and the notation "(dot)" is also attached below, but the notation "(dot)" may be omitted unless it does not interfere with understanding.

[0026] 1 includes a single AC power supply 10, a power transmitting coil 20 connected to the single AC power supply, four relay coils 30 (30-1 to 30-4) magnetically coupled to the power transmitting coil 20, and a power receiving coil 40 (40-1, 40-2; see FIG. 3) magnetically coupled to the relay coil 30. The impedances of the four relay coils 30 are adjusted so that a composite magnetic field generated by the four relay coils 30 generates a rotating magnetic field when an AC current flows through the power transmitting coil 20. Although the power receiving coil is not shown in FIG. 1, it can be appropriately placed within the rotating magnetic field generated by the relay coil 30 and used as a contactless power supply system.

[0027] In FIG. 1, Ii (i = 0 to 4) is the current flowing in each coil, and the direction of the arrow on the circle or ellipse around it indicates the relationship in the direction of the current flow. Hi (i = 1 to 4) is the magnetic field created by the current flowing in each repeater coil. The repeater coils 30-1 to 30-4 have the same self-inductance L1 and the same resistance R1, and are connected in series to a capacitor with capacitance C1 or C2. The transmitting coil located in the center has four inductances L0, and each inductance L0 is magnetically connected to the inductance L1 of each repeater coil 30-1 to 30-4 via a mutual inductance M.

[0028] The power transmission coil 20 shown in FIG. 1 is a rectangular loop coil, but is not limited to a rectangular loop, and may be a loop of any shape, such as a polygonal loop, a circular loop, or an elliptical loop. The power transmission coil 20 shown in FIG. 1 has four inductances that are magnetically coupled to the four relay coils 30, respectively. However, when the number of relay coils is other than four, the power transmission coil 20 may be configured to have the same number of inductances as the number of relay coils.

[0029] 1 shows four relay coils 30, but the number may be any number other than four. From the viewpoint of ease of adjusting the impedance to generate a rotating magnetic field, an even number is preferable, but an odd number is also acceptable as long as the impedance can be adjusted.

[0030] The following describes how to adjust the impedance for generating a rotating magnetic field using the relay coil in the configuration shown in FIG. In the configuration shown in Figure 1, the currents I(dot)1 and I(dot)3 flowing through the repeater coil have mutual induction coefficients of different signs, so they are out of phase, i.e., 180 degrees apart. Similarly, the currents I(dot)2 and I(dot)4 flowing through the repeater coil have mutual induction coefficients of different signs, so they are out of phase, i.e., 180 degrees apart.

[0031] If the phase of the current I1 in the repeater coil and the current I2 in the repeater coil are shifted by 90 degrees, the current phases of the four repeater coils will differ by 90 degrees. Therefore, let the impedance of the closed circuit through which the current I1 flows be Z(dot)1, and the impedance of the closed circuit through which the current I2 flows be Z(dot)2, then

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[0032] The resistance value of all four repeater coils is R1, so if the angular frequency of the power supply is ω, then

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[0033]

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[0034] Furthermore, if the effective values ​​of the currents flowing through all four relay coils are equal, a uniform magnetic field will be created, so

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[0035] In this system, all but C1 and C2 are known, and an exact solution can be found with only C1 and C2 as unknowns. Here, we will find C1 and C2 using the construction method shown in Figure 2. From Figure 2, if R1=X1=-X2, the condition is met. If R1=ωL1-1 / ωC1=-(ωL1-1 / ωC2), then tan ―1 ={(ωL1-1 / ωC1) / R1}=45[degrees] tan ―1 ={(ωL1-1 / ωC2) / R1}=45[degrees] Therefore, C1=1 / ω(ωL1-R1), C2=1 / ω(ωL 1+ If C1 and C2, which satisfy ωL1-R1, are connected to the repeater coil as shown in Figure 1, the current phase difference in the repeater coil will be 90 degrees. Here, since C1 > 0 physically, the condition for this system to be valid is ωL1-R1 > 0.

[0036] Figure 3 shows the actual coil arrangement. The distance between the coils is shown far apart for the sake of explanation, but in reality the coils are placed closer together. The thick arrow H in Figure 3 is the resultant vector of the magnetic field created by the repeater coil current I1 and the repeater coil current I3.

[0037] In the contactless power supply system 100 shown in FIG. 3, the four relay coils 30 are arranged around the power transmission coil 20 so as to surround the power transmission coil 20 when viewed from the normal direction (Z direction) of the power transmission coil 20, and are arranged at positions shifted by 90 degrees from the power transmission coil 20 in the xy plane.

[0038] The four relay coils 30 are arranged so that the normal directions (X direction, Y direction) of all of the relay coils intersect with the normal direction (Z direction) of the power transmitting coil 20. More specifically, the four relay coils 30 are arranged so as to form an angle of approximately 90 degrees with respect to the power transmitting coil 20. Here, "approximately 90 degrees" does not have to be strictly 90 degrees, and is intended to include a range of approximately ±10 degrees.

[0039] In this embodiment, the current phase of the repeater coil is analyzed by circuit analysis (AC theory).

[0040] (a) Current I1 in the relay coil The current I1 in the repeater coil is a loop current, and applying Kirchhoff's voltage law,

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[0041] (b) Current I2 in the relay coil The current I2 in the repeater coil is also a loop current, and when Kirchhoff's voltage law is applied, the current I2 is calculated as follows:

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[0042] (c) Current I3 of the relay coil The current I3 of the repeater coil is also a loop current, and when Kirchhoff's voltage law is applied, the sign of the mutual induction coefficient becomes negative. If we take this into account by giving the current I3 a negative sign, the current I3 will be as follows:

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[0043] (d) Relay coil current I4 The current I4 of the repeater coil is also a loop current, and when Kirchhoff's voltage law is applied, the sign of the mutual induction coefficient becomes negative. If this is taken into account by giving the current I4 a negative sign, the current I4 will be as follows:

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[0044] From (a) to (d) above, it can be confirmed that currents I1 to I4 are sequentially shifted in phase by 90 degrees. As can be seen from the above, a rotating magnetic field is generated even though a single power supply is used. If the receiving coil is within the rotating magnetic field, the decrease in power transmission efficiency can be suppressed even if its position changes.

[0045] Next, we will explain an example of generating a rotating magnetic field using six repeater coils with a single power supply, using the circuit diagram shown in Figure 4. Although Figure 4 is illustrated two-dimensionally for the purpose of explanation, in reality, the repeater coils and the power transmission coil are arranged perpendicular to each other.

[0046] 4 includes a single AC power supply 10, a power transmitting coil 20A connected to the single AC power supply, six relay coils 30A (30A-1 to 30A-6) magnetically coupled to the power transmitting coil 20A, and a power receiving coil 40 (see FIG. 6) magnetically coupled to the relay coil 30A. The impedances of the six relay coils 30A are adjusted so that a combined magnetic field generated by the six relay coils 30A generates a rotating magnetic field when an AC current flows through the power transmitting coil 20A. Components denoted by the same reference numerals are considered to be similar and their explanations may be omitted.

[0047] The relay coils 30A-1 to 30A-6 have the same self-inductance L1. The relay coils 30A-1 and 30A-4 have the same resistance Ra and are connected in series to a capacitor with a capacitance Ca. The relay coils 30A-2 and 30A-5 have the same resistance Rb and are connected in series to a capacitor with a capacitance Cb. The relay coils 30A-3 and 30A-6 have the same resistance Rc and are connected in series to a capacitor with a capacitance Cc. The central power transmission coil 20A has six inductances L0, and each inductance L0 is magnetically connected to the inductance L1 of the relay coils 30A-1 to 30A-6 via a mutual inductance M.

[0048] In Figure 4, the impedance of the right repeater coil

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[0049] Next, in the upper right corner of Figure 4,

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[0050] Next, in the bottom right of Figure 4,

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[0051] These impedances

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[0052] The current phasor diagram in Figure 5(b) takes into account the positive and negative mutual induction coefficients. Figure 5(b) shows that the current phase in each repeater coil differs by 60 degrees, and the circuit diagram in Figure 4 shows that a rotating magnetic field can be generated from six repeater coils. This eliminates the previous issue of changes in efficiency due to the angle between the transmitting and receiving coils, and enables highly efficient omnidirectional power supply using a single power source.

[0053] Figure 6 shows the relative positions of the transmitting coil, six relay circuits, and receiving circuit, as well as a circuit diagram of each. Although only one receiving coil 40 is shown in Figure 6, other coils can be placed as needed within the rotating magnetic field. If the receiving coil is placed within the rotating magnetic field, the decrease in power transmission efficiency can be suppressed even if its position changes.

[0054] In the contactless power supply system 100A shown in FIG. 6, the six relay coils 30A are arranged around the power transmission coil 20A so as to surround the power transmission coil 20A when viewed from the normal direction (Z direction) of the power transmission coil 20A, and are arranged at positions shifted by 60 degrees from the power transmission coil 20A in the xy plane.

[0055] The six relay coils 30A are arranged so that the normal directions (X and Y directions) of all the relay coils intersect with the normal direction (Z direction) of the power transmitting coil 20A. More specifically, the six relay coils 30A are arranged at approximately 90 degrees with respect to the power transmitting coil 20A.

[0056] Next, an example of generating a rotating magnetic field using eight repeater coils with a single power supply will be explained using the circuit diagram shown in Fig. 7. Although Fig. 7 is illustrated two-dimensionally for the purpose of explanation, in reality the repeater coils and the power transmission coil are arranged perpendicular to each other.

[0057] 7 includes a single AC power supply 10, a power transmitting coil 20B connected to the single AC power supply, eight relay coils 30B (30B-1 to 30B-8) magnetically coupled to the power transmitting coil 20B, and a power receiving coil 40 (see FIG. 9) magnetically coupled to the relay coil 30B. The impedances of the eight relay coils 30B are adjusted so that a composite magnetic field generated by the eight relay coils 30B generates a rotating magnetic field when an AC current flows through the power transmitting coil 20B. Components denoted by the same reference numerals are considered to be similar and their explanations may be omitted.

[0058] The relay coils 30B-1 to 30B-8 have the same self-inductance L1. The relay coils 30B-1 and 30B-5 have the same resistance R1 and are connected in series to a capacitor with a capacitance C1. The relay coils 30B-2 and 30B-6 have the same resistance R2 and are connected in series to a capacitor with a capacitance C2. The relay coils 30B-3 and 30B-7 have the same resistance R3 and are connected in series to a capacitor with a capacitance C3. The relay coils 30B-4 and 30B-8 have the same resistance R4 and are connected in series to a capacitor with a capacitance C4. The centrally located power transmission coil 20B has eight inductances L0, and each inductance L0 is magnetically connected to the inductance L1 of the relay coils 30B-1 to 30B-8 via a mutual inductance M.

[0059] In this circuit diagram, the impedance of the relay coil on the right side is

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[0060] Figure 9(a) shows an overall view of the coil arrangement of an omnidirectional power supply that generates a rotating magnetic field using eight repeater coils with a single power supply, as well as a circuit diagram of the repeater circuit and power receiving circuit. Figure 9(b) shows the arrangement of three repeater coils.

[0061] In the contactless power supply system 100B shown in FIG. 9(a), the eight relay coils 30B are arranged around the power transmission coil 20B so as to surround the power transmission coil 20B when viewed from the normal direction (Z direction) of the power transmission coil 20B, and are arranged at positions shifted by 45 degrees from the power transmission coil 20B in the xy plane.

[0062] The eight relay coils 30B are arranged so that the normal directions (X and Y directions) of all of the relay coils intersect with the normal direction (Z direction) of the power transmitting coil 20B. More specifically, the eight relay coils 30B are arranged at approximately 90 degrees with respect to the power transmitting coil 20A.

[0063] Furthermore, as shown in Figures 9(a) and 9(b), the eight relay coils 30B are arranged above and below the power transmission coil 20B alternately so that adjacent relay coils sandwich the power transmission coil 20B when viewed from a direction perpendicular to the normal direction of the power transmission coil. In the layout diagrams of the repeater coils shown in Figures 3 and 6, the mutual induction coefficient between the repeater coils is ignored, but there are cases where the mutual induction coefficient between the repeater coils cannot be ignored. As shown in Figure 9(b), when the transmitting coil is viewed horizontally, the mutual induction coefficient M' between the repeater coils can be ignored by arranging the repeater coils alternately above and below the transmitting coil. In this way, the width of the repeater coil can be increased to a position where the mutual induction coefficient M' is sufficiently small, thereby preventing a decrease in efficiency.

[0064] Figures 9(c) and 9(d) show examples in which the shape of the repeater coil has been further improved. Figure 9(c) is a schematic plan view of the repeater coil as seen from above, and Figure 9(d) is a schematic perspective view as seen obliquely from above. The repeater coil of this improved example has a bent portion (the portion surrounded by a dotted oval in FIG. 9(d)) that matches the bent portion of the power transmitting coil (the portion surrounded by a dotted circle in FIG. 9(c)), resulting in strong coupling between the power transmitting coil and the repeater coil. By matching the shape and size of the repeater coil to those of the power transmitting coil in this way, the mutual induction coefficient M' between the repeater coils can be made negligible.

[0065] In the embodiments described above, the repeater coil generates only horizontal magnetic flux. In this configuration, the power receiving efficiency decreases when the receiving coil is placed horizontally, as shown in Fig. 10. Therefore, next, we will show an embodiment in which a repeater coil is added to generate vertical magnetic flux.

[0066] The coil arrangement configuration shown in Fig. 11 adds four vertical magnetic flux generating relay coils 30V (30V-1 to 30V-3) to the configuration shown in Fig. 3 and arranges them horizontally in the same plane as the power transmitting coil. Note that for convenience of drawing, the vertical magnetic flux generating relay coils are not shown behind the power transmitting coil in Fig. 11.

[0067] 11 includes a single AC power supply 10, a power transmitting coil 20 connected to the single AC power supply, four vertically arranged relay coils 30 (30-1 to 30-4) and four horizontally arranged relay coils 30V (30V-1 to 30V-3) magnetically coupled to the power transmitting coil 20, and a power receiving coil 40 (40-1, 40-2) magnetically coupled to the relay coil 30. The impedances of the four vertically arranged relay coils 30 and the four horizontally arranged relay coils 30V are adjusted so that a composite magnetic field generated by the eight relay coils 30, 30V generates a rotating magnetic field when an AC current flows through the power transmitting coil 20.

[0068] In Fig. 11, the horizontal magnetic field created by the horizontal magnetic flux relay coil is H H The impedance of the vertical magnetic flux relay coil is adjusted to shift the phase by 90 degrees, and the vertical magnetic field generated by the vertical magnetic flux relay coil is expressed as H V is shown as

[0069] The coil arrangement shown in FIG. 11 adds four vertical magnetic flux generating relay coils 30V and arranges them in the same plane as the power transmitting coil. By shifting the phase of the vertically arranged relay coils 30 by 90 degrees, it is possible to receive power with vertical magnetic flux even at the receiving coil position shown in FIG. 10. The vertical magnetic field generated by the four 30V vertical magnetic flux generating relay coils can also be adjusted in impedance to create a rotating magnetic field, making it possible to supply power in all directions.

[0070] FIG. 12 shows another embodiment in which a relay coil is added to generate a vertical magnetic flux. The coil arrangement configuration shown in FIG. 12 is the same as the configuration shown in FIG. 6, except that six vertical magnetic flux generating relay coils 30VV (30VV-1 to 30VV-6) are added and arranged horizontally in the same plane as the power transmission coils.

[0071] 12 includes a single AC power supply 10, a power transmitting coil 20 connected to the single AC power supply, six relay coils 30A (30A-1 to 30A-6) magnetically coupled to the power transmitting coil 20A, six horizontally arranged relay coils 30VV (30VV-1 to 30VV-6), and a power receiving coil 40 (see FIG. 6) magnetically coupled to the relay coil 30A. The impedances of the 12 relay coils 30A, 30VV are adjusted so that a composite magnetic field generated by the 12 relay coils 30A, 30VV generates a rotating magnetic field when an AC current flows through the power transmitting coil 20A.

[0072] In Fig. 12, the horizontal magnetic field created by the horizontal magnetic flux relay coil is H H The impedance of the vertical magnetic flux relay coil is adjusted to shift the phase by 90 degrees, and the vertical magnetic field generated by the vertical magnetic flux relay coil is expressed as H V is shown as It can be seen that the magnetic field generated in the vertical magnetic flux generating relay coil 30VV generates a magnetic flux that interlinks with the power receiving coil, thereby expanding the range of contactless power transfer (see FIG. 13).

[0073] FIG. 13 is a diagram schematically showing a magnetic field generated in the vicinity of a configuration in which a vertical magnetic flux generation relay coil is added to the vertical magnetic flux generation relay coil 30VV shown in FIG. By adding the vertical magnetic flux relay coil 30VV-1, a magnetic field is also generated above the transmitting coil, further expanding the range of contactless power transfer. With this contactless power transfer system, contactless power transfer is possible in all three-dimensional directions using a rotating magnetic field, regardless of the angle of the receiving coil. [Explanation of symbols]

[0074] 10 Single AC power source 20, 20A, 20B transmitting coil 30, 30A, 30B, 30V, 30VV Relay coil 40 receiving coil 100, 100A, 100B, 100-1, 100A-1 Contactless Power Supply System

Claims

1. a single AC power source; a transmitting coil connected to the single AC power supply; a plurality of relay coils magnetically coupled to the power transmission coil; a receiving coil that is magnetically coupled to the relay coil, the plurality of relay coils have impedances adjusted so that a combined magnetic field generated by the plurality of relay coils generates a rotating magnetic field when an alternating current flows through the power transmission coil.

2. The contactless power transfer system according to claim 1 , wherein the plurality of relay coils are arranged around the power transmission coil so as to surround the power transmission coil when viewed in a normal direction of the power transmission coil.

3. 3. The contactless power supply system according to claim 1, wherein the plurality of relay coils are arranged around the power transmission coil at positions spaced apart from the power transmission coil by 360 degrees / n (n is an integer) when viewed from a normal direction of the power transmission coil.

4. 4. The wireless power supply system according to claim 1, wherein the plurality of relay coils are arranged with respect to the power transmission coil such that normal directions of all of the relay coils intersect with a normal direction of the power transmission coil.

5. 5. The contactless power transfer system according to claim 4, wherein the plurality of relay coils are arranged with respect to the power transmission coil such that normal directions of all of the relay coils form an angle of approximately 90 degrees with respect to a normal direction of the power transmission coil.

6. the plurality of relay coils are arranged around the power transmission coil so as to surround the power transmission coil when viewed from a normal direction of the power transmission coil, 6. The wireless power supply system according to claim 1, wherein at least some adjacent relay coil groups among the plurality of relay coils are alternately arranged so as to sandwich the power transmission coil when viewed from a direction orthogonal to a normal direction of the power transmission coil.

7. 7. The wireless power supply system according to claim 1, wherein at least some of the plurality of relay coils have a bent portion that corresponds to a shape of a bent portion of the power transmission coil.

8. 8. The contactless power supply system according to claim 1, wherein the plurality of relay coils have current phases that differ from one another.

9. 9. The wireless power supply system according to claim 1, further comprising a vertical magnetic flux generating relay coil having a normal direction different from a normal direction of the plurality of relay coils and generating a magnetic field orthogonal to a composite magnetic field generated by the plurality of relay coils.

10. The contactless power transfer system according to claim 9 , wherein the vertical magnetic flux generating relay coil is a relay coil having a normal direction that is the same as a normal direction of the power transmission coil.

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