Resonator device and wireless power transmission system using the same

Abstract

A resonator device using a C-coupled balun that is suitable for resonator-coupled wireless power transmission and can be used even when the diameter of the resonator coil is large is provided. [Solution] This resonator device 2 comprises a first external coupling adjustment capacitor 31 having one end connected to a first external circuit connection terminal 2a, a second external coupling adjustment capacitor 32 having one end connected to a second external circuit connection terminal 2b, a frequency adjustment capacitor 33 having one end connected to the other end of the first external coupling adjustment capacitor 31 and the other end connected to the other end of the second external coupling adjustment capacitor 32, respectively, and a resonator coil 4 having two or more spiral-shaped lines arranged in close proximity to each other, with their central ends connected to each other and connected to the other end of the first external coupling adjustment capacitor 31 and their other ends connected to each other and connected to the other end of the second external coupling adjustment capacitor 32.

Description

[Technical Field]

[0001] The present invention relates to a resonator device for resonator-coupled wireless power transmission that uses a C-coupled balun, and also to a wireless power transmission system that uses the resonator device. [Background technology]

[0002] In a resonator-coupling wireless power transfer system, wireless power is transferred by coupling and resonating resonator devices via a non-radiative electromagnetic field (electric or magnetic field). The transfer efficiency of this wireless power transfer is determined by the unloaded Q value of the resonator device and the coupling coefficient k between the resonator devices, and improving the transfer efficiency requires improving both characteristics. The coupling coefficient k depends on the diameter of the resonator coil included in the resonator device and the transmission distance, and it is possible to improve the coupling coefficient k over long distances by increasing the diameter of the resonator coil.

[0003] Here, a resonator coil is a coil such as a spiral coil with a line formed in a spiral shape. It can be classified into two types: one that resonates by itself due to its distributed constant (distributed constant resonator that resonates at the self-resonant frequency), and one that acts as an inductor and resonates at a predetermined resonant frequency in combination with a capacitor to form a lumped constant resonator. A resonator coil acts as an inductor when the line length of the coil is sufficiently short compared to the wavelength and the operating frequency is in a frequency range lower than the self-resonant frequency. While the resonant frequency of a distributed constant resonator must be adjusted by adjusting the line length, the resonant frequency of a lumped constant resonator is easily adjusted by adjusting the capacitance of the capacitor. The inductance value of a resonator coil remains almost constant at sufficiently low frequencies, but as the frequency increases and approaches the self-resonant frequency, it appears to increase, and at frequencies higher than the self-resonant frequency, it becomes capacitive.

[0004] Furthermore, on the power transmitting and receiving sides of a wireless power transmission system, the resonator coils are balanced circuits, while the external circuits (the power supply circuit on the power transmitting side and the load circuit on the power receiving side) are unbalanced circuits. Therefore, a balun (balanced-unbalanced converter) is required between the resonator coil and the external circuit to perform balanced-unbalanced conversion and impedance adjustment. For this reason, the resonator device has a balun. As a balun, in addition to a typical one that uses loop coupling, a C-coupled balun is also known, as shown in Non-Patent Document 1. Furthermore, a C-coupled balun can be combined with a resonator coil to form a lumped constant resonator, as described below, which makes it easy to adjust the resonant frequency.

[0005] 14 shows a wireless power transmission system 101. This wireless power transmission system 101 uses a resonator device 102 on the power transmitting side and a resonator device 102' on the power receiving side. The resonator device 102 has a C-coupled balun 103 and a resonator coil 104, and the resonator device 102' has a C-coupled balun 103' and a resonator coil 104'. The resonator device 102 (more specifically, the C-coupled balun 103) is coupled to a power supply circuit 105, which is an external circuit, and the resonator device 102 (more specifically, the C-coupled balun 103') is coupled to a load circuit 105', which is an external circuit.

[0006] The C-coupling balun 103 includes a first external coupling adjustment capacitor 131, a second external coupling adjustment capacitor 132, and a resonance frequency adjustment capacitor 133. The capacitance values ​​of the first external coupling adjustment capacitor 131 and the second external coupling adjustment capacitor 132 are both C ke , the capacitance value of the resonance frequency adjustment capacitor 133 is C t When the self-inductance value of the resonator coil 104 is L, the resonant frequency (indicated by angular frequency ω0) of the resonator device 102 can basically be expressed by the following equation (1). TIFF2026042653000002.tif15170 Even in the case of C-coupled balun 103', even though the specific values ​​(capacitance value, self-inductance value) of each element are different from those in the case of C-coupled balun 103, the relationship therebetween can be expressed by equation (1).

[0007] Furthermore, in the wireless power transmission system 101, when the external coupling coefficient ke between the resonator device 102 and the power supply circuit 105 (the degree of coupling therebetween) is set to a value according to the coupling coefficient k between the resonator devices 102 and 102′ (for example, a value equal to the coupling coefficient k), it is possible to achieve an impedance matching state between the resonator device 102 and the power supply circuit 105. The external coupling coefficient ke is determined by the capacitance values ​​C ke Therefore, the capacitance value C of the first external coupling adjusting capacitor 131 and the second external coupling adjusting capacitor 132 can be adjusted in accordance with the coupling coefficient k between the resonator devices 102 and 102′. ke The capacitance value C of the resonance frequency adjusting capacitor 133 is adjusted to satisfy the formula (1) so that the resonance frequency (angular frequency ω0) does not change. t By adjusting the capacitance value C of the external coupling adjustment capacitor in accordance with the coupling coefficient k, wireless power transmission with good transmission efficiency becomes possible. In the resonator device 102', similarly to the resonator device 102, it is possible to achieve an impedance matching state between the resonator device 102' and the load circuit 105'. In the following description of this application, the capacitance value C of the external coupling adjustment capacitor is adjusted in accordance with the coupling coefficient k. ke When is adjusted, the capacitance value of the external coupling adjustment capacitor C is adjusted so that the external coupling coefficient ke is equal to the coupling coefficient k. ke shall be adjusted. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Teruhiko Yamamoto, Tetsuya Ishida, Toshio Ishizaki, "Investigation of Input / Output Coupling Control Method Using C-Coupled Balun in Resonator Direct-Coupled Excitation WPT System," IEICE Technical Report, Institute of Electronics, Information and Communication Engineers, December 2014, WPT2014-76 Summary of the Invention [Problem to be solved by the invention]

[0009] However, if the diameter of the resonator coil 104 is increased to transmit power wirelessly over long distances, the line length becomes longer, resulting in a large self-inductance value L. In this case, if a C-coupled balun 103 is used in the resonator device 102, the relationship of formula (1) may not be realized if the resonant frequency is equal to or higher than the frequency of the ISM band and the coupling coefficient k is large (the coupling between the resonator devices is strong), as described below. The same applies to the resonator device 102'.

[0010] 15 shows the relationship between the desired capacitance C of the first external coupling adjustment capacitor 131 and the second external coupling adjustment capacitor 132 and the coupling coefficient k (horizontal axis) when the resonant frequency is 6.78 MHz (a frequency in the ISM band), the self-inductance value of the resonator coil 104 is 20 μH, and the matching impedance is 50 Ω. ke (curve x) and the desired capacitance value C of the resonant frequency adjustment capacitor 133 t The capacitance C of the first external coupling adjustment capacitor 131 and the second external coupling adjustment capacitor 132 increases with an increase in the coupling coefficient k. ke increases, but the capacitance value Ct of the resonance frequency adjustment capacitor 133 becomes a negative value when the coupling coefficient k is about 0.06 or more, and the relationship of formula (1) cannot be realized.

[0011] The present invention has been made in view of the above circumstances, and its purpose is to provide a resonator device for resonator-coupled wireless power transmission that uses a C-coupled balun that can be applied even when the diameter of the resonator coil is large. [Means for solving the problem]

[0012] In order to achieve the above object, the resonator device described in claim 1 is a resonator device for wireless power transmission using a resonator coupling method, and includes: a first external coupling adjustment capacitor having one end connected to a first external circuit connection terminal; a second external coupling adjustment capacitor having one end connected to a second external circuit connection terminal; a frequency adjustment capacitor having one end connected to the other end of the first external coupling adjustment capacitor and the other end connected to the other end of the second external coupling adjustment capacitor, respectively; and a resonator coil having two or more spiral-shaped lines arranged in close proximity to each other, with their central ends connected to each other and connected to the other end of the first external coupling adjustment capacitor and their other ends connected to each other and connected to the other end of the second external coupling adjustment capacitor.

[0013] A resonator device according to a second aspect of the present invention is the resonator device according to the first aspect, wherein the two or more lines are arranged between each other on the same plane.

[0014] The resonator device according to claim 3 is the resonator device according to claim 2, wherein the two or more lines have the same number of turns and inter-line pitch, where N is the number of lines (N≧2), and the N lines are arranged rotated by 360 / N degrees.

[0015] A resonator device according to a fourth aspect of the present invention is the resonator device according to the first aspect, wherein the two or more lines are arranged inside or outside each other on the same plane.

[0016] A resonator device according to a fifth aspect of the present invention is the resonator device according to the first aspect, wherein the two or more lines are arranged on different planes.

[0017] A wireless power transmission system according to claim 6 uses the resonator device according to any one of claims 1 to 5 on at least one of the power transmitting side and the power receiving side of wireless power transmission. [Effects of the Invention]

[0018] The resonator device for wireless power transmission using the resonator coupling method of the present invention allows the diameter of the resonator coil to be increased even when a C-coupled balun is used, and the wireless power transmission system of the present invention easily enables wireless power transmission over long distances even when a C-coupled balun is used in the resonator device. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram of a resonator device according to an embodiment of the present invention and a wireless power transmission system using the same; [Figure 2] 10A to 10C are plan views showing examples of a first embodiment of a resonator coil of the resonator device of the same, where (a) is when N=2, (b) is when N=4, and (c) is when N=8. [Figure 3] 10 is a graph showing the self-inductance value when N is changed in the first form of the resonator coil of the resonator device of the same. [Figure 4] FIG. 10 is a plan view of a case where N=1 (basic resonator coil) as a comparative example of the first embodiment of the resonator coil of the resonator device of the above embodiment. [Figure 5] 10 is a graph showing the capacitance value of a capacitor for adjusting the resonance frequency versus the coupling coefficient k in the first form of the resonator coil of the resonator device according to the first embodiment; [Figure 6] FIG. 2 is a plan view showing a second example of the resonator coil of the resonator device of the first embodiment. [Figure 7] 10 is a graph showing the capacitance value of the resonant frequency adjusting capacitor versus the coupling coefficient k in the second form of the resonator coil of the resonator device according to the first embodiment; [Figure 8] 10A and 10B are side views showing an example of a third mode of the resonator coil of the resonator device of the same, where (a) is a two-layer planar case, and (b) is a three-layer planar case. [Figure 9] 10 is a plan view showing an example of a configuration in which both the first and second configurations of the resonator coil of the resonator device are used. FIG. [Figure 10]10 is a graph showing the relationship between the transmission distance and the coupling coefficient k based on actual measurements in a wireless power transmission system using the resonator device of the above embodiment. [Figure 11] 10A to 10D are characteristic diagrams based on a simulation showing S parameters in a wireless power transmission system using the resonator device of the above embodiment, where (a) to (d) are obtained by changing the transmission distance. [Figure 12] 10A to 10D are characteristic diagrams based on an experiment showing S parameters in a wireless power transmission system using the resonator device of the above, where (a) to (d) are graphs showing the S parameters when the transmission distance is changed. [Figure 13] 10 is a graph showing the relationship between transmission distance and transmission efficiency in a wireless power transmission system using the resonator device of the first embodiment. [Figure 14] 1 is a schematic diagram of a conventional resonator device and a wireless power transmission system using the same. [Figure 15] 10 is a graph showing the capacitance value of an external coupling adjusting capacitor and the capacitance value of a resonance frequency adjusting capacitor versus coupling coefficient k in a conventional resonator device. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a wireless power transmission system 1 can have a resonator device 2 according to an embodiment of the present invention on the power transmitting side and a resonator device 2' according to an embodiment of the present invention on the power receiving side. However, at least one of the resonator device 2 and the resonator device 2' may be used on the power transmitting side and the power receiving side. The resonator device 2 and the resonator device 2' are coupled to each other via a non-radiating electromagnetic field with a coupling coefficient k and resonate. Furthermore, a power supply circuit 5, which is an external circuit, is coupled to the resonator device 2', and a load circuit 5', which is also an external circuit, is coupled to the resonator device 2'. As shown in FIG. 1, the power supply circuit 5 can be represented by an equivalent circuit of a high-frequency signal source 51 and an output resistor 52, and the load circuit 5' can be represented by an equivalent circuit of a load resistor 51'.

[0021] The resonator device 2 is a resonator device for wireless power transmission using a resonator coupling method, and includes a C-coupled balun 3 and a resonator coil 4 (see FIG. 1). Similarly, the resonator device 2' is a resonator device for wireless power transmission using a resonator coupling method, and includes a C-coupled balun 3' and a resonator coil 4' (see FIG. 1).

[0022] The C-coupling balun 3 includes a first external coupling adjustment capacitor 31, a second external coupling adjustment capacitor 32, and a frequency adjustment capacitor 33. One end of the first external coupling adjustment capacitor 31 is connected to the first external circuit connection terminal 2a. Furthermore, one end of the second external coupling adjustment capacitor 32 is connected to the second external circuit connection terminal 2b. The first external circuit connection terminal 2a and the second external circuit connection terminal 2b are each connected to a power supply circuit 5, which is an external circuit. One end of the frequency adjustment capacitor 33 is connected to the other end of the first external coupling adjustment capacitor 31 and the other end of the second external coupling adjustment capacitor 32, respectively. The first external coupling adjustment capacitor 31 and the second external coupling adjustment capacitor 32 have the same capacitance value C ke The resonance frequency adjusting capacitor 33 has a capacitance value C t is.

[0023] The C-coupling balun 3' includes a first external coupling adjustment capacitor 31', a second external coupling adjustment capacitor 32', and a frequency adjustment capacitor 33'. One end of the first external coupling adjustment capacitor 31' is connected to the first external circuit connection terminal 2a'. Furthermore, one end of the second external coupling adjustment capacitor 32' is connected to the second external circuit connection terminal 2b'. The first external circuit connection terminal 2a' and the second external circuit connection terminal 2b' are each connected to a load circuit 5', which is an external circuit. One end of the frequency adjustment capacitor 33' is connected to the other end of the first external coupling adjustment capacitor 31' and the other end of the second external coupling adjustment capacitor 32', respectively. The first external coupling adjustment capacitor 31' and the second external coupling adjustment capacitor 32' have the same capacitance value C ke The resonance frequency adjusting capacitor 33' has a capacitance value C t ´.

[0024] Next, the resonator coil 4 will be described together with the characteristics of the resonator device 2 and the wireless power transmission system 1. The resonator coil 4 has a self-inductance value L. Unless otherwise specified, the resonator coil 4' is similar to the resonator coil 4 but has a self-inductance value L'.

[0025] The resonator coil 4 has two or more spiral-shaped lines 41, 42, .... The two or more lines 41, 42, ... are arranged close to each other. The two or more lines 41, 42, ... are connected to each other at their central ends (winding start) and connected to the other end of the first external coupling adjustment capacitor 31 (in other words, one end of the frequency adjustment capacitor 33). The two or more lines 41, 42, ... all have the same direction (right-handed or left-handed winding). The two or more lines 41, 42, ... are connected to each other at their other ends (winding end) and connected to the other end of the second external coupling adjustment capacitor 32 (in other words, the other end of the frequency adjustment capacitor 33). The spiral shape refers to a curved shape that starts winding at the central side and moves away from the center as it turns on a plane.

[0026] The resonator coil 4 can be specifically configured as a first, second, or third type, which will be described below.

[0027] The first form of the resonator coil 4, as shown in Figures 2(a), (b), and (c), is one in which two or more lines 41, 42, ... are arranged on the same plane, inter-line. If the number of the two or more lines 41, 42, ... is N (N≧2), each of the N lines 41, 42, ... can have the same number of turns and inter-line pitch, and can be arranged rotated by 360 / N degrees. In this case, one end of each of the N lines 41, 42, ... is connected to each other at the center, forming the center of a spiral shape. Note that in Figure 2, (a) shows N=2 and includes lines 41 and 42; (b) shows N=4 and includes lines 41, 42, 43, and 44; and (c) shows N=8 and includes lines 41, 42, 43, 44, 45, 46, 47, and 48.

[0028] Curve a (the curve connecting circles) in Figure 3 shows the self-inductance value L [μH] obtained when N was varied in a simulation (simulation using an electromagnetic field simulator) conducted by the inventors of the present application. Also, the dots in Figure 3 show the self-inductance value L obtained in an experiment when N = 1, 2, 4, and 8. The resonator coil 4 for each N is made by uniformly winding copper wire lines 41, 42, ... with a wire diameter of 1.6 mm, with a diameter of 50 cm, and an imaginary line connecting the start and end of the winding crosses any of the lines 41, 42, ... a total of nine times (including the end of the winding). Note that Figure 3 also shows the value for a comparative example where N = 1 (i.e., the case where only one line 41 is included, as shown in Figure 4) (hereinafter referred to as the basic resonator coil).

[0029] As shown in Fig. 3, the simulation and experiment are in good agreement, and the self-inductance value L decreases as N increases. This indicates that the N lines 41, 42, ... can be considered to form resonator coils each having a self-inductance value approximately 1 / N of that of the basic resonator coil and connected in parallel.

[0030] FIG. 5 shows the capacitance C of the resonant frequency adjusting capacitor 33 versus the coupling coefficient k (horizontal axis) between the resonator devices when the resonant frequency is 6.78 MHz and the matching impedance is 50 Ω. t (vertical axis) represents the capacitance value C of the capacitor for adjusting the resonance frequency. t When N=1 (curve b) (basic resonator coil), the coupling coefficient k becomes negative when the coupling coefficient is about 0.06 or more, as shown in Fig. 15, but when N=2 (curve c), the coupling coefficient k does not become negative until the coupling coefficient is about 0.3, and when N=4 (curve d) and N=8 (curve e), the coupling coefficient k does not become negative even if it is 1. Therefore, the first form of resonator coil 4 can use the C-coupled balun 3 with a wide range of coupling coefficient k.

[0031] Next, a second embodiment of the resonator coil 4 will be described. In the second embodiment of the resonator coil 4, two or more lines 41, 42, ... are arranged inside or outside each other on the same plane, as shown in Fig. 6. In Fig. 6, the line 41 is an inner part and is arranged inside the line 42. The line 42 is an outer part and is arranged outside the line 41. Fig. 6 shows a resonator coil 4 composed of two lines, one large and one small, 41 and 42, but it is also possible to arrange one or more lines with a larger diameter outside them.

[0032] Figure 6 shows a configuration in which the basic resonator coil shown in Figure 4 is divided into two. Line 41 is the innermost line with approximately 6.4 turns, and line 42 is the outermost line with approximately 2.6 turns. Line 41 and line 42 are considered to form resonator coils with their own self-inductance values ​​and are connected in parallel. As described above, the basic resonator coil is configured by uniformly winding copper wire lines 41, 42, ... with a diameter of 1.6 mm, and a virtual line connecting the beginning and end of the winding with a diameter of 50 cm intersects any of the lines 41, 42, ... a total of nine times (including the end of the winding). The self-inductance value L of the basic resonator coil is 20.02 μH in simulation and 22.02 μH in experiment. In contrast, the self-inductance value L of the second form of resonator coil 4 with the configuration shown in Figure 6 is 4.66 μH in simulation and 4.92 μH in experiment. The simulation and experimental results were in good agreement.

[0033] FIG. 7 shows the capacitance C of the resonant frequency adjusting capacitor 33 versus the coupling coefficient k (horizontal axis) between the resonator devices when the resonant frequency is 6.78 MHz and the matching impedance is 50 Ω. t (vertical axis) represents the capacitance value C of the capacitor for adjusting the resonance frequency. tIn the configuration of Fig. 6 (curve f), the coupling coefficient k does not become negative until approximately 0.22. Therefore, the second form of the resonator coil 4 can use the C-coupled balun 3 with a wide range of coupling coefficient k. Note that curve g in Fig. 7 is a re-plot of curve c (for N = 2) in Fig. 5 for comparison. Curve f has a shape that is roughly the same as curve g, which indicates that the second form of the resonator coil 4 can be considered, like the first form, as two or more lines 41, 42, ... forming resonator coils each having a smaller self-inductance value than the basic resonator coil and connected in parallel.

[0034] Next, a third embodiment of the resonator coil 4 will be described. In the third embodiment of the resonator coil 4, two or more lines 41, 42, ... are arranged on different planes, as shown in Figures 8(a) and 8(b). Figure 8(a) is a side view of a two-layered plane in which the line 41 is arranged on the first plane and the line 42 is arranged on the second plane, and Figure 8(b) is a side view of a three-layered plane in which the line 41 is arranged on the first plane, the line 42 is arranged on the second plane, and the line 43 is arranged on the third plane. The plan views corresponding to Figures 8(a) and 8(b) are the same as those shown in Figure 4 (basic resonator coil).

[0035] Assuming that the resonator coil 4 for each layer is made of copper wire with a diameter of 1.6 mm, with evenly wound traces 41, 42, etc., with a diameter of 50 cm, and that the imaginary line connecting the beginning and end of the winding crosses any of the traces 41, 42, etc. a total of nine times (including the end of the winding), the self-inductance value L for the one-layer planar case (basic resonator coil) is 20.02 μH, as shown above. The self-inductance values ​​L for the two-layer planar case and the three-layer planar case are 17.09 μH and 15.6 μH, respectively, which are smaller than the one-layer planar case. Therefore, even if the coupling coefficient k becomes relatively large, the capacitance value Ct of the resonant frequency adjustment capacitor can be prevented from becoming negative. Therefore, the third form of the resonator coil 4 allows the use of a C-coupled balun 3 with a wide range of coupling coefficient k.

[0036] Although the first, second, and third forms of the resonator coil 4 have been described above, the resonator coil 4 may also be configured to use two or all three of these forms. For example, Fig. 9 shows a form that uses both the first and second forms, in which the lines 41, 42, 43, and 44 form the first form with N=4, and the lines 45, 46, 47, and 48 form the first form with N=4, and the lines 41, 42, 43, and 44 and the lines 45, 46, 47, and 48 form the second form.

[0037] Next, in the wireless power transmission system 1, the relationship between the transmission distance D and the coupling coefficient k is measured, and using this, it is confirmed through simulation and experiment that sufficient impedance matching is achieved and good transmission efficiency is obtained even when the transmission distance D changes.

[0038] Figure 10 shows the measured values ​​of the relationship between the transmission distance D (horizontal axis) and the coupling coefficient k (vertical axis). In Figure 10, curve h represents the case where the resonator coil 4 on the power transmitting side has a diameter of 150 cm and uses both the first and second configurations (the configuration shown in Figure 9), and the resonator coil 4' on the power receiving side has a diameter of 50 cm and uses the first configuration with N=2. Curve i represents the case where the resonator coils on both the power transmitting side and the power receiving side are basic resonator coils with a diameter of 50 cm. Figure 10 shows that curve h has a larger coupling coefficient k than curve i, and at a distance of 100 cm, the coupling coefficient k is about 2.4 times higher.

[0039] 11(a) to 11(d) and 12(a) to 12(d) show the S parameters when the resonator coil 4 on the power transmitting side has a diameter of 150 cm and is configured using both the first and second configurations (the configuration shown in FIG. 9), and the resonator coil 4' on the power receiving side has a diameter of 50 cm and is configured using the first configuration with N=2. The horizontal axis f represents frequency [MHz], and the vertical axis represents the S parameter [dB]. 11(a) to 11(d) are simulation results, while 12(a) to 12(d) are experimental results. In FIGS. 11(a) and 12(a), the transmission distance D is 25 cm, in FIGS. 11(b) and 12(b), the transmission distance D is 50 cm, in FIGS. 11(c) and 12(c), the transmission distance D is 75 cm, and in FIGS. 11(d) and 12(d), the transmission distance D is 100 cm. In each diagram, curve j represents the transmission characteristics, curve l represents the reflection characteristics of the resonator device 2 on the power transmitting side, and curve m represents the reflection characteristics of the resonator device 2' on the power receiving side.

[0040] Table 1 below shows the coupling coefficient k and the capacitance values ​​C of the first external coupling adjustment capacitor 31 and the second external coupling adjustment capacitor 32 in the resonator device 2 at the respective transmission distances D [cm] in the simulation and the experiment. ke [pF] and the capacitance value C of the resonant frequency adjustment capacitor 33 t [pF], the capacitance value C of the first external coupling adjustment capacitor 31′ and the second external coupling adjustment capacitor 32′ in the resonator device 2′ ke '[pF] and the capacitance value C of the resonance frequency adjustment capacitor 33' t ´ [pF]. Note that C ke , C t , C ke ´, C t ´ is optimized by adjusting the capacitance to between several pF and several tens of pF, taking into account coil loss.

[0041] [Table 1]

[0042] 11(a) to (d) and 12(a) to (d), it can be seen that the simulation and experimental results show good agreement in power transmission characteristics, and that sufficient impedance matching is achieved even when the transmission distance D between the resonator device 2 and the resonator device 2' changes. Furthermore, even when the transmission distance D is 100 cm, a reflection characteristic of 15 dB or more (see FIGS. 11(d) and 12(d)) is obtained, indicating that good power transmission characteristics can be obtained over long distances.

[0043] Figure 13 shows the relationship between the transmission distance D [cm] (horizontal axis) and the transmission efficiency η [%] (vertical axis). In Figure 13, curves n and o represent the results when the resonator coil 4 on the power transmitting side has a diameter of 150 cm and is a configuration using both the first and second configurations (the configuration shown in Figure 9), and the resonator coil 4' on the power receiving side has a diameter of 50 cm and is the first configuration with N=2, while curves p and q represent the results when both the resonator coil on the power transmitting side and the resonator coil on the power receiving side are basic resonator coils with a diameter of 50 cm. Curves n and p are based on simulations, and curves o and q are based on experiments.

[0044] As can be seen from Figure 13, the simulation and experimental results show good agreement in terms of transmission efficiency η. Furthermore, when the transmission distance D is approximately 65 cm or more, the transmission efficiency η of curves n and o is higher, and in the experiment, the transmission efficiency η was approximately 62% when the transmission distance D was 75 cm and approximately 43% when it was 100 cm, demonstrating an improvement over long distances.

[0045] Therefore, as described above, the resonator device 2 (and 2') can be applied to a wide range of coupling coefficients k even when the C-coupled balun 3 (and 3') is used, and the diameter of the resonator coil 4 (and 4') can be increased to transmit wireless power over long distances. Furthermore, the wireless power transmission system 1 can easily transmit wireless power over long distances even when the C-coupled balun 3 (and 3') is used in the resonator device 2 (and 2').

[0046] The above describes the resonator device and the wireless power transmission system using the same according to the embodiment of the present invention. However, the present invention is not limited to the above-described embodiment, and various design modifications are possible within the scope of the claims. [Explanation of symbols]

[0047] 1. Wireless power transmission system 2, 2´ resonator device 2a, 2a´ First external circuit connection terminal 2b, 2b´ Second external circuit connection terminals 3,3´ C coupled balun 31 First external coupling adjustment capacitor 32 Second external coupling adjustment capacitor 33 Frequency adjustment capacitor 4, 4´ resonator coil 41, 42, 43, 44, 45, 46, 47, 48 tracks 5 Power circuit 51 High Frequency Signal Source 52 Output Resistance 5´ Load circuit 51´ Load Resistor C ke , C ke ´ Capacitance value of external coupling adjustment capacitor C t , C t ´ Capacitance value of the capacitor for adjusting the resonance frequency L, L´ Self-inductance value of resonator coil k coupling coefficient ω0 Resonant frequency (angular frequency)

Claims

1. A resonator device for resonator-coupled wireless power transmission, comprising: a first external coupling adjustment capacitor having one end connected to the first external circuit connection terminal; a second external coupling adjustment capacitor having one end connected to the second external circuit connection terminal; a frequency adjusting capacitor having one end connected to the other end of the first external coupling adjusting capacitor and the other end connected to the other end of the second external coupling adjusting capacitor, respectively; a resonator coil having two or more spiral-shaped lines arranged close to each other, with one end on the center side connected to each other and connected to the other end of the first external coupling adjusting capacitor, and the other ends connected to each other and connected to the other end of the second external coupling adjusting capacitor; A resonator device comprising:

2. 10. The resonator device according to claim 1, A resonator device in which the two or more lines are arranged between each other on the same plane.

3. 3. The resonator device according to claim 2, A resonator device in which the two or more lines have the same number of turns and pitch between lines, where N (N≧2) is the number of lines, and the lines are arranged rotated by 360 / N degrees.

4. 10. The resonator device according to claim 1, A resonator device in which the two or more lines are arranged inside or outside each other on the same plane.

5. 10. The resonator device according to claim 1, A resonator device in which the two or more lines are arranged on different planes.

6. A wireless power transmission system in which the resonator device according to any one of claims 1 to 5 is used on at least one of the power transmitting side and the power receiving side of wireless power transmission.

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