Wireless power transmission system

Abstract

To provide a wireless power transmission system in which the labor of adjusting impedance can be reduced.SOLUTION: A wireless power transmission system 10 is configured to be able to transmit AC power in a noncontact manner via power transmission side electrodes 34A, 34B, 36A, 36B included in a power transmission side resonance circuit 20 and power reception side electrodes 54A, 54B, 56A, 56B included in a power reception side resonance circuit 40. The wireless power transmission system includes first phase shifters 40A, 40B that adjust an impedance Zin to get closer to a reference impedance Z0 by adjusting a voltage phase of the power transmission side resonance circuit 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a transmission system for transmitting AC power in a non-contact manner. [Background technology]

[0002] In recent years, wireless power transmission systems that transmit AC power from a power transmitter to a power receiver in a non-contact manner have been developed. For example, some of these systems transmit AC power in a non-contact manner by utilizing a resonance phenomenon that occurs between a power transmitter resonant circuit and a power receiver resonant circuit, each of which is configured as a series resonant circuit in which an electrode and a coil are arranged in series. Wireless power transmission systems that utilize such a resonance phenomenon include those that utilize electric field coupling or magnetic field coupling.

[0003] Patent document 1 discloses a wireless power transmission system using an electric field coupling method in which the resonant frequency of a power transmission coupler consisting of a first and second electrodes and a first inductor arranged in a conductive housing of a power transmission device is set to be the same as the resonant frequency of a power receiving coupler consisting of a third and fourth electrodes and a second inductor arranged in a conductive housing of a power receiving device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6182551 Summary of the Invention [Problem to be solved by the invention]

[0005] In a wireless power transmission system such as that described in Patent Document 1, in order to bring the power transmitting resonant circuit and the power receiving resonant circuit into a resonant state, it is necessary to adjust the impedance so that the input impedance of the transmission unit as seen from the power transmitting port is close to the impedance (reference impedance) of the power receiving load. Such impedance adjustment is performed, for example, by providing an impedance matching device including a variable capacitor or a variable inductor in the power transmitting resonant circuit or the power receiving resonant circuit and adjusting the capacitance and inductance values.

[0006] However, when adjusting the input impedance using the impedance matching device, it is necessary to change the physical quantities of both capacitance and inductance, which poses a problem of time and effort required for the adjustment work.

[0007] The present invention provides a wireless power transmission system that can reduce the effort required for impedance adjustment. [Means for solving the problem]

[0008] A wireless power transmission system according to a first aspect of the present invention is a wireless power transmission system including a transmission unit configured to be able to transmit AC power contactlessly via a power transmission electrode included in a power transmission side resonant circuit and a power receiving electrode included in a power receiving side resonant circuit, and further including a first phase adjustment unit that adjusts the impedance so that it approaches a predetermined reference impedance by adjusting the phase of the voltage of the power transmission side resonant circuit.

[0009] A wireless power transmission system according to a second aspect of the present invention is a wireless power transmission system including a transmission unit configured to be able to transmit AC power contactlessly via a power transmission electrode included in a power transmission side resonant circuit and a power receiving electrode included in a power receiving side resonant circuit, and further including a second phase adjustment unit that adjusts the impedance so that it approaches a predetermined reference impedance by adjusting the phase of the voltage of the power receiving side resonant circuit.

[0010] A wireless power transmission system according to a third aspect of the present invention is a wireless power transmission system including a transmission unit configured to be able to transmit AC power contactlessly via a power transmission electrode included in a power transmission side resonant circuit and a power receiving electrode included in a power receiving side resonant circuit, and is provided with a first phase adjustment unit that adjusts the phase of the voltage of the power transmission side resonant circuit and a second phase adjustment unit that adjusts the phase of the voltage of the power receiving side resonant circuit, and adjusts the phase of the voltage using the first phase adjustment unit and the second phase adjustment unit so that the impedance approaches a predetermined reference impedance.

[0011] In the wireless power transmission system according to the present invention, a plurality of transmission units may be provided, and the power transmission electrodes included in each of the plurality of transmission units may be arranged on the same plane, and the power receiving electrodes included in each of the plurality of transmission units may also be arranged on the same plane. [Effects of the Invention]

[0012] According to the wireless power transmission system of the first aspect of the present invention, the phase of the power transmitting resonant circuit can be adjusted so as to approach a predetermined reference impedance, thereby enabling impedance adjustment without using an impedance matching box, thereby reducing the effort required for adjustment.

[0013] According to the wireless power transmission system of the second aspect of the present invention, the phase of the power receiving-side resonant circuit can be adjusted so as to approach a predetermined reference impedance, thereby enabling impedance adjustment without using an impedance matching box, thereby reducing the effort required for adjustment.

[0014] According to the wireless power transmission system of the third aspect of the present invention, the phases of the power receiving-side resonant circuit and the power transmitting-side resonant circuit can be adjusted so as to approach a predetermined reference impedance, thereby enabling impedance adjustment without using an impedance matching box, thereby reducing the effort required for adjustment. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram schematically showing the configuration of an electric circuit of the entire wireless power transmission system according to the first embodiment of the present invention. [Figure 2] 2(a) is a plan view showing the configuration of a power transmitting side electrode included in the power transmitting side resonant circuit of the wireless power transmission system shown in FIG. 1, FIG. 2(b) is a plan view showing the configuration of a power receiving side electrode included in the power receiving side resonant circuit of the wireless power transmission system shown in FIG. 1, and FIG. 2(c) is a diagram showing the configuration of the power transmitting side electrode and the power receiving side electrode when viewed from the A1 direction shown in FIG. 2(a) and the A2 direction shown in FIG. 2(b). [Figure 3] Figure 3(a) is a diagram showing a state in which the power transmitting electrode of the power transmitting side transmission unit and the power receiving electrode of the power receiving side transmission unit are misaligned and do not completely overlap in a planar view, and Figure 3(b) is a diagram showing a state in which each power receiving side electrode has rotated around the midpoint between each power receiving side electrode from a position facing each power transmitting side electrode. [Figure 4] FIG. 4 is a table showing the return loss calculated using electromagnetic field simulation when no phase adjustment is performed by the first phase shifter and the second phase shifter in each mode in which the relative positional relationship between each power transmitting-side electrode in the power transmitting-side transmission unit and each power receiving-side electrode in the power receiving-side transmission unit is different. [Figure 5] FIG. 5 is a table showing the phase adjustment value and return loss calculated for each mode when phase adjustment is performed via the first and second phase shifters using electromagnetic field simulation so that the input impedance approaches the reference impedance. [Figure 6] FIG. 6 is a diagram schematically showing the configuration of an electric circuit of the entire wireless power transmission system according to the second embodiment. [Figure 7] FIG. 7 is a table showing the phase adjustment value and return loss calculated for each mode when phase adjustment is performed via the first phase shifter so that the input impedance approaches the reference impedance in each mode shown in FIG. 4 using electromagnetic field simulation in the wireless power transmission system of the second embodiment. [Figure 8]FIG. 8(a) is a diagram showing a schematic diagram of the electrical circuit configuration of the entire wireless power transmission system according to the third embodiment, and FIG. 8(b) is a table showing calculated phase adjustment values ​​and return losses when phase adjustment is performed via a second phase shifter using electromagnetic field simulation so that the input impedance approaches the reference impedance in the wireless power transmission system according to the third embodiment. [Figure 9] FIG. 9(a) is a diagram showing a schematic diagram of the electrical circuit configuration of the entire wireless power transmission system according to the fourth embodiment, and FIG. 9(b) is a table showing calculated phase adjustment values ​​and return losses when phase adjustment is performed by the first phase shifter and the second phase shifter using electromagnetic field simulation so that the input impedance approaches the reference impedance in the wireless power transmission system according to the fourth embodiment. [Figure 10] FIG. 10(a) is a diagram showing a schematic diagram of the electrical circuit configuration of the entire wireless power transmission system according to the fifth embodiment, and FIG. 10(b) is a table showing calculated phase adjustment values ​​and return losses when phase adjustment is performed by the first phase shifter using electromagnetic field simulation so that the input impedance approaches the reference impedance in the wireless power transmission system according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] A wireless power transmission system 10 according to one embodiment of the present invention will now be described with reference to the drawings. In each drawing, Cx and Cy indicate horizontal directions that are orthogonal to each other, and Cz indicates a vertical direction. FIG. 1 is a diagram showing a schematic configuration of the entire wireless power transmission system 10 according to this embodiment. As shown in FIG. 1, the wireless power transmission system 10 includes a power transmitting-side resonant circuit 20 and a power receiving-side resonant circuit 40, and has a function of contactlessly transmitting (feeding) AC power using an electric field coupling method. The power transmitting-side resonant circuit 20 includes a power transmitting-side load 22, a high-frequency power source 24, and power transmitting-side transmission units 30 and 32 connected via a distributor 26. Since the power transmitting-side transmission units 30 and 32 have substantially the same configuration, the following description will mainly focus on the power transmitting-side transmission unit 30, and will omit a description of the power transmitting-side transmission unit 32 as appropriate.

[0017] The power transmission-side load 22 is the internal impedance of the high-frequency power supply 24 and has a reference impedance Z0. In this embodiment, the reference impedance Z0 is set to 50Ω, for example. The divider 26 includes ports A1, A2, and B1 to B4, and incorporates a connection line L1 that electrically connects port A1 to port B1, a connection line L2 that electrically connects port A1 to port B3, a connection line L3 that electrically connects port A2 to port B2, and a connection line L4 that electrically connects port A2 to port B4. The connection lines L1 to L4 are set to have the same length. For example, the connection lines L1 to L4 are made of coaxial cables, and have characteristic impedances that are approximately the same as the reference impedance Z0.

[0018] The power-transmitting-side transmission unit 30 includes an inductor 31A and a power-transmitting-side electrode 34A connected in series to port B1 of the divider 26 via connection lines M1 and N1, and an inductor 31B and a power-transmitting-side electrode 34B connected to port B2 of the divider 26 via connection lines M2 and N2. A first phase shifter (first phase adjustment unit) 40A is provided between the connection lines M1 and M2 and the connection lines N1 and N2. The first phase shifter 40A has a function of adjusting the phase of the voltage in the power-transmitting-side transmission unit 30. More specifically, the first phase shifter 40A has a function of shifting the phase of the input voltage by a preset phase adjustment value φ1 and outputting the result. Note that the first phase shifter 40A may be a mechanical phase shifter or an electronic phase shifter.

[0019] The lengths of the connection lines M1 and M2 are set to be equal, and similarly, the lengths of the connection lines N1 and N2 are set to be equal. Each of the connection lines M1, M2, N1, and N2 is, for example, configured using a coaxial cable, and has a characteristic impedance substantially equal to the reference impedance Z0. The power-transmitting-side transmission unit 32 also has substantially the same configuration as the power-transmitting-side transmission unit 30, and includes a first phase shifter 40B and power-transmitting-side electrodes (power-transmitting electrodes) 36A and 36B.

[0020] In this embodiment, when no phase adjustment is performed via the first phase shifter 40A (in other words, pass-through), the length of the transmission path from the power transmitting side port P1 through ports A1 and B1, the first phase shifter 40A, and the inductor 31A to the power transmitting side electrode 34A is set to be equal to the length of the transmission path from the power transmitting side port P2 through ports A2 and B2, the first phase shifter 40A, and the inductor 31B to the power transmitting side electrode 34B.

[0021] The power receiving side resonant circuit 40 includes a power receiving side load 42 and power receiving side transmission units 50 and 52 connected via a combiner 46. This combiner 46 has the function of electrically connecting the power receiving side load 42 to each of the power receiving side transmission units 50 and 52, and includes connection lines L5 and L6 that electrically connect port D1 to ports C1 and C3, respectively, and connection lines L7 and L8 that electrically connect port D2 to ports C2 and C4, respectively. The connection lines L5 to L8 are set to be equal in length. The power receiving side load 42 is an internal impedance such as a rectifier or secondary battery, and this impedance is configured to be equal to a reference impedance Z0.

[0022] Since the power receiving side transmission units 50 and 52 have the same configuration, the following description will mainly focus on the power receiving side transmission unit 50, and the description of the power receiving side transmission unit 52 will be omitted as appropriate.

[0023] The power receiving side transmission unit 50 includes an inductor 51A and a power receiving side electrode (power receiving electrode) 54A connected in series to port C1 of the combiner 46 via connection lines M5 and N5, and an inductor 51B and a power receiving side electrode (power receiving electrode) 54B connected to port C2 of the combiner 46 via connection lines M6 and N6. A second phase shifter (second phase adjustment unit) 50A is provided between the connection lines M5 and M6 and the connection lines N5 and N6. This second phase shifter 50A has the same configuration as the first phase shifter 40A described above and has the function of adjusting the phase of the voltage in the power receiving side transmission unit 50. The second phase shifter 50A may be a mechanical phase shifter or an electronic phase shifter.

[0024] In this embodiment, when no phase adjustment is performed via the second phase shifter 50A (in other words, pass-through), the length of the transmission path from the power receiving side port P3 through ports D1 and C1, the second phase shifter 50A, and the inductor 51A to the power receiving side electrode 54A is set to be equal to the length of the transmission path from the power receiving side port P4 through ports D2 and C2, the second phase shifter 50A, and the inductor 51B to the power receiving side electrode 54B.

[0025] 2(a) is a plan view showing the arrangement of the power transmitting electrodes 34A, 34B of the power transmitting side transmission unit 30 and the power transmitting electrodes 36A, 36B of the power transmitting side transmission unit 32. As shown in FIG. 2(a), the power transmitting electrodes 34A, 34B of the power transmitting side transmission unit 30 and the power transmitting electrodes 36A, 36B of the power transmitting side transmission unit 32 are arranged on the same plane and have the same configuration. Therefore, the following description will mainly focus on the power transmitting side electrodes 34A, 34B of the power transmitting side transmission unit 30, and will omit the description of the power transmitting side electrodes 36A, 36B of the power transmitting side transmission unit 32 as appropriate. The power transmission side electrodes 34A, 34B have a generally rectangular external shape in a plan view and are arranged so that their short sides face each other, and are arranged so that when the power transmission side electrodes 34A, 34B are rotated 90 degrees around the midpoint R1 of an imaginary line connecting the points that bisect the short sides of the power transmission side electrodes 34A, 34B, they overlap with the power transmission side electrodes 36A, 36B.

[0026] 2(b) is a plan view showing the arrangement of the power receiving-side electrodes 54A, 54B of the power receiving-side transmission unit 50 and the power receiving-side electrodes 56A, 56B of the power receiving-side transmission unit 52. As shown in FIG. 2(b), the power receiving-side electrodes 54A, 54B of the power receiving-side transmission unit 50 and the power receiving-side electrodes 56A, 56B of the power receiving-side transmission unit 52 are arranged to face directly above (in other words, directly above in the Cz direction) the power transmitting-side electrodes 34A, 34B and the power transmitting-side electrodes 36A, 36B described above. Furthermore, the power receiving-side electrodes 54A, 54B and the power receiving-side electrodes 56A, 56B each have a substantially rectangular external shape in a plan view and have the same configuration. Therefore, the following description will mainly focus on the power receiving-side electrodes 54A, 54B of the power receiving-side transmission unit 50, and description of the power receiving-side electrodes 56A, 56B of the power receiving-side transmission unit 52 will be omitted where appropriate.

[0027] The power receiver-side electrodes 54A, 54B have substantially the same configuration as the power transmitter-side electrodes 34A, 34B described above, are arranged on the same plane with their short sides facing each other, and are arranged so that when the power receiver-side electrodes 54A, 54B are rotated 90 degrees around a midpoint R2 of an imaginary line connecting the points that bisect the short sides of the power receiver-side electrodes 54A, 54B, they overlap with the power receiver-side electrodes 56A, 56B.

[0028] Here, Figure 2(c) is a diagram showing the arrangement of the power transmitting side electrodes 34A, 34B, 36A, 36B of the power transmitting side transmission units 30, 32 and the power receiving side electrodes 54A, 54B, 56A, 56B of the power receiving side transmission units 50, 52 when viewed from the A1 direction and the A2 direction shown in Figures 2(a) and 2(b).

[0029] 2(c), the power transmitting electrodes 34A, 34B, 36A, and 36B constituting the power transmitting transmission units 30 and 32 and the power receiving electrodes 54A, 54B, 56A, and 56B constituting the power receiving transmission units 50 and 52 are arranged parallel to each other and facing each other at a predetermined distance α. In the following description, the positions of the power transmitting electrodes 34A, 34B, 36A, and 36B shown in FIGS. 2(a) and 2(c) are referred to as reference positions ST as appropriate.

[0030] Next, a method for adjusting the power transmission state by electric field coupling using the first phase shifters 40A, 40B and the second phase shifters 50A, 50B in the wireless power transmission system 10 will be described. In the wireless power transmission system 10, the first phase shifters 40A, 40B and the second phase shifters 50A, 50B are used to change the phase of the voltage, thereby changing the direction of the electric field vector, thereby changing the polarization state during electric field coupling and adjusting the degree of coupling (in other words, cross polarization characteristics). For example, when the degree of coupling is at a maximum value, the electric field vectors on the power transmitting side and the power receiving side are oriented in the same direction, and the input impedance Zin takes on a maximum value.

[0031] When the polarized waves on the power transmitting side formed around the power transmitting-side electrodes 34A, 34B, 36A, and 36B are orthogonal to the polarized waves on the power receiving side formed around the power receiving-side electrodes 54A, 54B, 56A, and 56B during electric field coupling, the degree of coupling is minimized and the input impedance Zin is low. Also, if the relative positions of the power transmitting-side electrodes 34A, 34B, 36A, and 36B and the power receiving-side electrodes 54A, 54B, 56A, and 56B change, the degree of coupling may decrease and the electric field vectors on the power transmitting side and the power receiving side may not be oriented in the same direction but may be oriented in different directions.

[0032] However, by using the first phase shifters 40A, 40B and the second phase shifters 50A, 50B to perform phase-shift power feeding, the direction of the electric field vector on the power transmitting side and the power receiving side can be changed so that it is the same, or the direction can be further changed so that it is different on the power transmitting side and the power receiving side, thereby changing the degree of coupling. This change in the degree of coupling can then change the input impedance Zin. In other words, by using the first phase shifters 40A, 40B and the second phase shifters 50A, 50B to perform phase-shift power feeding, it is possible to adjust the magnitude of the input impedance Zin.

[0033] Here, when the input impedance Zin is larger or smaller than the reference impedance Z0, the reflection loss increases due to mismatch in electric field coupling. On the other hand, when the input impedance Zin is close to the reference impedance Z0, the reflection loss decreases. Therefore, by performing phase-shift feeding using the first phase shifters 40A, 40B and the second phase shifters 50A, 50B, the input impedance Zin can be adjusted to a value close to the reference impedance Z0, thereby improving the transmission efficiency.

[0034] Fig. 3(a) is a diagram showing a state in which the power receiver-side electrodes 54A, 54B, 56A, and 56B are displaced in the Cx and Cy directions from the reference position ST in a plan view. Fig. 3(b) is a diagram showing a state in which the power receiver-side electrodes 54A, 54B, 56A, and 56B are rotated from the reference position ST around the Cz axis in a plan view, with the midpoint R2 as the rotation center. In Fig. 3(b), imaginary lines that bisect the opposing short sides of the power receiver-side electrodes 56A and 56B and the opposing short sides of the power receiver-side electrodes 54A and 54B are indicated by dashed lines, and imaginary lines that bisect the opposing short sides of the power transmitter-side electrodes 34A and 34B and the opposing short sides of the power transmitter-side electrodes 36A and 36B are indicated by dashed lines as appropriate. As shown in Figures 3(a) and 3(b), the distance in the Cx direction of the midpoint R2 of the power receiving side electrodes 54A, 54B, 56A, and 56B relative to the midpoint R1 of the power transmitting side electrodes 34A, 34B, 36A, and 36B in a planar view is denoted as β, the distance in the Cy direction is denoted as γ, and the distance in the Cz direction is denoted as α (see Figure 2), and the rotation angle of the power receiving side electrodes 54A, 54B, 56A, and 56B from the reference position ST in a planar view is denoted as δ.

[0035] Next, a phase difference power supply method will be explained in which the phase adjustment value φ1 of the first phase shifter 40A, the phase adjustment value φ2 of the first phase shifter 40B, the phase adjustment value ξ1 of the second phase shifter 50A, and the phase adjustment value ξ2 of the second phase shifter 50B are used as the phase adjustment value.

[0036] Fig. 4 is a table showing the return loss calculated by electromagnetic field simulation when the phase adjustment values ​​φ1, φ2, ξ1, and ξ2 are all set to 0, that is, when the relative positional relationships between the power transmitter electrodes 34A, 34B, 36A, and 36B and the power receiver electrodes 54A, 54B, 56A, and 56B in a pass-through state are set to Modes A to E. As shown in Fig. 4, Modes A to C show the return loss when the power transmitter electrodes 34A, 34B, 36A, and 36B and the power receiver electrodes 54A, 54B, 56A, and 56B face each other in the Cz (vertical) direction and are positioned such that only the distance α (see Fig. 2(c)) is different, being 160 mm, 280 mm, and 400 mm. In this case, the distances β, γ, and angle δ are all set to 0. Mode D shows the reflection loss when α=280 mm, β=250 mm, γ=150 mm, and δ=0°, and Mode E shows the reflection loss when α=280 mm, β=0 mm, γ=0 mm, and δ=60°.

[0037] In this embodiment, the electromagnetic field simulation is performed under the assumption that all of the following conditions (A) to (D) are satisfied, and the return loss is calculated. In the following description, the calculation conditions that satisfy all of the conditions (A) to (D) will be referred to as the "calculation conditions" where appropriate. (A) The inductances of inductors 31A, 31B of power transmitting side transmission unit 30 and inductors 31C, 31D of power transmitting side transmission unit 32 are all 5.53 μH, and the inductances of inductors 51A, 51B of power receiving side transmission unit 50 and inductors 51C, 51D of power receiving side transmission unit 52 are also each 5.53 μH. (B) The capacitance formed between the power transmitting side electrode 34A and the power transmitting side electrode 34B and the capacitance formed between the power transmitting side electrode 36A and the power transmitting side electrode 34B are both set to 12.46 pF, and the capacitance formed between the power receiving side electrode 54A and the power receiving side electrode 54B and the capacitance formed between the power receiving side electrode 56A and the power receiving side electrode 56B are also each set to 12.46 pF. (C) When the first phase shifters 40A, 40B and the second phase shifters 50A, 50B are used, there is no passing resistance. (D) The frequency of the AC voltage supplied by the high frequency power supply 24 is set to 13.56 MHz.

[0038] 5 is a table showing the phase adjustment values ​​φ1, φ2, ξ1, ξ2 and return loss values ​​calculated by electromagnetic field simulation under the above calculation conditions using first phase shifters 40A, 40B and second phase shifters 50A, 50B so that input impedance Zin approaches reference impedance Z0 in the above-described modes A to E. Here, return loss is shown as a negative value, and the larger the absolute value (i.e., the smaller the value), the smaller the return loss, or in other words, the higher the transmission efficiency.

[0039] As shown in Figure 5, the return loss is reduced in all modes A to E. In the case of mode A, the return loss is reduced from -1.66 dB (see Figure 4) to -42.3 dB by setting φ1 = -80°, φ2 = 90°, ξ1 = -122°, and ξ2 = -72°. In the case of mode B, the return loss is reduced from -13.84 dB (see Figure 4) to -52.9 dB by setting φ1 = 121°, ξ1 = 4°, φ2 = -167°, and ξ2 = 3°. In the case of mode C, the return loss is reduced from -5.12 dB (see Figure 4) to -55.5 dB by setting φ1 = 93°, ξ1 = -20°, φ2 = -13°, and ξ2 = 112°. In the case of mode D, the return loss is reduced from -0.59 dB (see Figure 4) to -63.9 dB by setting φ1 = 123°, ξ1 = 18°, φ2 = -62°, and ξ2 = -117°. In the case of mode E, the return loss is reduced from -2.51 dB (see Figure 4) to -43.8 dB by setting φ1 = -112°, ξ1 = 137°, φ2 = 148°, and ξ2 = -124°.

[0040] According to the wireless power transmission system 10 of this embodiment, it is possible to adjust the phase of the voltage in the power receiving side resonant circuit 40 and the power transmitting side resonant circuit 20 so that the input impedance Zin approaches a predetermined reference impedance Z0. This allows the input impedance Zin to be adjusted so as to approach the reference impedance Z0 without using an impedance matching box, thereby reducing the effort required for impedance matching (adjustment).

[0041] In the wireless power transmission system 10 of the first embodiment, the first phase shifters 40A, 40B and the second phase shifters 50A, 50B are provided in both the power transmitting-side resonant circuit 20 and the power receiving-side resonant circuit 40, but the present invention is not limited to this. For example, the first phase shifters 40A, 40B may be provided in the power transmitting-side resonant circuit 20, and no phase shifter may be provided in the power receiving-side resonant circuit 40. A wireless power transmission system 60 according to this embodiment will be described with reference to FIGS. 6 and 7. In the following description, components that are the same as those in the first embodiment will be denoted by the same reference numerals as appropriate, and descriptions thereof will be omitted, and different configurations will be mainly described.

[0042] As shown in FIG. 6 , the wireless power transmission system 60 has the same functions and configuration as the wireless power transmission system 10 of the first embodiment in a state where the phase adjustment values ​​ξ1 = 0 and ξ2 = 0 of the second phase shifters 50A and 50B are set. The wireless power transmission system 60 includes power receiving side transmission units 61 and 62 instead of the above-described power receiving side transmission units 50 and 52. The power receiving side transmission unit 61 has the same configuration as the power receiving side transmission unit 50 except that the inductors 51A and 51B are electrically connected to the combiner 46 via connection lines M7 and M8, respectively. The connection lines M7 and M8 are made of a coaxial cable or the like having a characteristic impedance substantially equal to the reference impedance Z0 and are provided to have the same length. The power receiving side transmission unit 62 also has substantially the same configuration and function as the above-described power receiving side transmission unit 61.

[0043] FIG. 7 is a table showing the results of calculating the phase adjustment values ​​φ1, φ2 and the magnitude of return loss when phase adjustment is performed so that the input impedance Zin approaches the reference impedance Z0 when the positional relationships shown in the above-mentioned modes A to E are used, using electromagnetic field simulation under the above-mentioned calculation conditions.

[0044] As shown in Figure 7, in Mode A, by setting φ1 = -75° and φ2 = 69°, the return loss is reduced from -1.66 dB (see Figure 4) to -37.1 dB. In Mode B, by setting φ1 = 122° and φ2 = -166°, the return loss is reduced from -13.84 dB (see Figure 4) to -40.2 dB. In Mode D, by setting φ1 = 161° and φ2 = -56°, the return loss is reduced from -0.59 dB (see Figure 4) to -19.8 dB. In Mode E, by setting φ1 = -100° and φ2 = 136°, the return loss is reduced from -2.51 dB (see Figure 4) to -26.1 dB.

[0045] In this way, even when the first phase shifters 40A, 40B are provided only in the power transmitting side resonant circuit 20 and the input impedance Zin is adjusted to approach the reference impedance Z0, the impedance can be adjusted in the same manner as in the wireless power transmission system 10 of the first embodiment. As a result, the impedance can be adjusted without using an impedance matching box, thereby reducing the workload for impedance adjustment.

[0046] Although the wireless power transmission system 10 of the first embodiment has been described above with reference to an example in which the first phase shifters 40A, 40B and the second phase shifters 50A, 50B are provided in both the power transmitting-side resonant circuit 20 and the power receiving-side resonant circuit 40, the present invention is not limited to this. For example, the second phase shifters 50A, 50B may be provided in the power receiving-side resonant circuit 40, and no phase shifter may be provided in the power transmitting-side resonant circuit 20. A wireless power transmission system 70 of this embodiment will be described with reference to FIGS. 8(a) and 8(b). In the following description, components that are the same as those in the first embodiment will be denoted by the same reference numerals as appropriate, and descriptions thereof will be omitted, and different configurations will be mainly described.

[0047] As shown in FIG. 8(a), the wireless power transmission system 70 has the same functions and configuration as the wireless power transmission system 10 of the first embodiment in a state where the phase adjustment values ​​φ1=0 and φ2=0 of the first phase shifters 30A and 30B are set. As shown in FIG. 8(a), the wireless power transmission system 70 includes power transmission-side transmission units 71 and 72 instead of the power transmission-side transmission units 30 and 32 described above. The power transmission-side transmission unit 71 has the same configuration as the power transmission-side transmission unit 30 of the above embodiment, except that the inductors 31A and 31B are electrically connected to the divider 26 via connection lines M9 and M10. The connection lines M9 and M10 each have a characteristic impedance substantially equal to the reference impedance Z0 and are configured to have the same length using a coaxial cable or the like. The power transmission-side transmission unit 72 also has substantially the same configuration and functions as the power transmission-side transmission unit 71 described above.

[0048] FIG. 8(b) is a table showing the calculation results of the phase adjustment values ​​ξ1 and ξ2 and the return loss when phase adjustment is performed using the electromagnetic field simulation under the above calculation conditions in mode B. As shown in FIG. 8(b), when the phase adjustment values ​​are ξ1 = 61° and ξ2 = 8°, the return loss decreases from −13.84 dB (see FIG. 4) to −37.7 dB. As described above, even when the second phase shifters 50A and 50B are installed only in the power-receiving-side transmission units 50 and 52 and the voltage phase of the power-receiving-side resonant circuit 40 is adjusted to approach the reference impedance Z0, impedance adjustment can be performed similarly to the wireless power transmission system 10 in the first embodiment. As a result, impedance adjustment can be performed without using an impedance matching box, thereby reducing the effort required for adjustment.

[0049] In the wireless power transmission system 10 of the first embodiment, the first phase shifters 40A, 40B and the second phase shifters 50A, 50B are provided in both the power transmitting side transmission units 30, 32 and the power receiving side transmission units 50, 52, but the present invention is not limited to this. For example, the first phase shifter 40A and the second phase shifter 50A may be provided only in the power transmitting side transmission unit 30 and the power receiving side transmission unit 50.

[0050] A wireless power transmission system 80 according to the fourth embodiment will be described with reference to Figures 9(a) and 9(b). In the following description, the same components as those in the wireless power transmission systems 10, 60, and 70 according to the first to third embodiments will be denoted by the same reference numerals as appropriate, and a description thereof will be omitted, with the focus being on different configurations. As shown in Figure 9(a), the wireless power transmission system 80 has the same configuration as the wireless power transmission system 10 according to the first embodiment, except that only the power transmitting transmission unit 30 and the power receiving transmission unit 50 are provided with a first phase shifter 40A and a second phase shifter 50A.

[0051] 9(a), the wireless power transmission system 80 has the same functions and configuration as the wireless power transmission system 10 of the first embodiment in a state where the phase adjustment value φ2 of the first phase shifter 40B is set to 0 and the phase adjustment value ξ2 of the second phase shifter 50B is set to 0. Fig. 9(b) is a table showing the calculation results of the phase adjustment values ​​φ1 and φ2 and the return loss when phase adjustment is performed using the first phase shifter 40A and the second phase shifter 50A in the relative positional relationship of Mode B using electromagnetic field simulation under the above calculation conditions so that the input impedance Zin approaches the reference impedance Z0.

[0052] 9(b), when the phase adjustment values ​​φ1=58° and ξ1=−83° are set, the return loss decreases from −13.84 dB (see FIG. 4) to −42.9 dB. In this way, even when phase shifters are provided only in the power transmitting side transmission unit 30 and the power receiving side transmission unit 50 and the voltage phases of the power transmitting side resonant circuit 20 and the power receiving side resonant circuit 40 are adjusted so that the input impedance Zin approaches the reference impedance Z0, impedance adjustment can be performed similarly to the wireless power transmission system 10 in the first embodiment. As a result, impedance adjustment can be performed without using an impedance matching box, reducing the effort required for adjusting contactless power transmission.

[0053] Although the wireless power transmission system 10 of the first embodiment has been described above with reference to an example in which phase shifters are installed in the power transmitting transmission units 30 and 32 and the power receiving transmission units 50 and 52, the present invention is not limited to this. For example, the first phase shifter 40A may be installed only in the power transmitting transmission unit 30. A wireless power transmission system 90 of this embodiment will be described with reference to FIGS. 10(a) and 10(b). In the following description, components that are the same as those in the wireless power transmission systems 10, 60, 70, and 80 of the first to fourth embodiments will be denoted by the same reference numerals as appropriate and will not be described again, with the focus being on the different configurations.

[0054] 10(a), the wireless power transmission system 90 has the same functions and configuration as the wireless power transmission system 10 of the first embodiment in a state where the phase adjustment values ​​are set to ξ1=0, φ2=0, and ξ2=0. The wireless power transmission system 90 has the same configuration as the wireless power transmission system 10 of the first embodiment, except that the first phase shifter 40A is provided only in the power transmitting side transmission unit 30, and the first phase shifter 40B and the second phase shifters 50A and 50B are not provided.

[0055] Fig. 10(b) is a table showing the calculation results of the phase adjustment value φ1 and return loss when phase adjustment is performed using electromagnetic field simulation under the above calculation conditions using first phase shifter 40A so that input impedance Zin approaches reference impedance Z0 in the relative positional relationship of mode B. As shown in Fig. 10(b), when the phase adjustment value φ1 is set to 65°, the return loss decreases from -13.84 dB (see Fig. 4) to -27.7 dB.

[0056] In this way, even when the first phase shifter 40A is provided in only one of the power transmitting side transmission units 30 and the voltage phases of the power transmitting side resonant circuit 20 and the power receiving side resonant circuit 40 are adjusted so that the input impedance Zin approaches the reference impedance Z0, impedance adjustment can be performed in the same manner as in the wireless power transmission system 10 in the first embodiment. As a result, impedance adjustment can be performed without using an impedance matching box, and the effort required for adjustment can be reduced.

[0057] In the first embodiment, the wireless power transmission system 10 includes two power transmitting-side transmission units 30 and 32. However, the present invention is not limited to this. For example, the wireless power transmission system 10 may include only one power transmitting-side transmission unit, or may include three or more power transmitting-side transmission units.

[0058] In the first embodiment, the wireless power transmission system 10 includes two power receiving-side transmission units 50 and 52. However, the present invention is not limited to this. For example, the wireless power transmission system 10 may include only one power receiving-side transmission unit, or may include three or more power receiving-side transmission units.

[0059] In the above first to fifth embodiments, the wireless power transmission systems 10, 60, 70, 80, and 90 of the electric field coupling type have been described as examples, but the present invention is not limited to this. For example, the present invention may be applied to a wireless power transmission system of the magnetic field coupling type.

[0060] The present invention can be implemented in various modes that incorporate various improvements, modifications, or variations based on the knowledge of those skilled in the art without departing from the spirit of the invention. Furthermore, the present invention can be implemented in a form in which any of the features of the invention are substituted with other technologies within the scope of producing the same functions or effects. [Explanation of symbols]

[0061] 10,60,70,80,90 Wireless power transmission system 20 Power transmission side resonant circuit 22 Transmission side load 24 High frequency power supply 26 Distributor 30 Power transmission unit 34A, 34B, 36A, 36B Power transmission side electrode (power transmission electrode) 40 Receiving side resonant circuit 40A, 40B 1st phase shifter (1st phase adjustment section) 42 Receiving load 46 Synthesizer 50 Receiving transmission unit 50A, 50B 2nd phase shifter (2nd phase adjustment section) 54A, 54B, 56A, 56B Power receiving electrodes (power receiving electrodes) Z0 Reference Impedance Zin Input impedance α, β, γ distance δ angle Cx,Cy horizontal direction Cx vertical direction

Claims

1. A wireless power transmission system including a transmission unit configured to be able to transmit AC power in a contactless manner via a power transmission electrode included in a power transmission-side resonant circuit and a power reception electrode included in a power reception-side resonant circuit, a first phase adjusting unit that adjusts the phase of the voltage of the power transmitting side resonant circuit so that the impedance approaches a predetermined reference impedance; Wireless power transmission system.

2. A wireless power transmission system including a transmission unit configured to be able to transmit AC power in a contactless manner via a power transmission electrode included in a power transmission-side resonant circuit and a power reception electrode included in a power reception-side resonant circuit, a second phase adjusting unit that adjusts the phase of the voltage of the power receiving side resonant circuit so that the impedance approaches a predetermined reference impedance; Wireless power transmission system.

3. A wireless power transmission system including a transmission unit configured to be able to transmit AC power in a contactless manner via a power transmission electrode included in a power transmission-side resonant circuit and a power reception electrode included in a power reception-side resonant circuit, a first phase adjustment unit that adjusts the phase of the voltage of the power transmitting side resonant circuit; a second phase-shift adjusting unit that adjusts the phase of the voltage of the power receiving-side resonant circuit; Equipped with adjusting the phase of the voltage using the first phase adjusting unit and the second phase shift adjusting unit so that the impedance approaches a predetermined reference impedance; Wireless power transmission system.

4. a plurality of the transmission units; the power transmission electrodes included in each of the plurality of transmission units are arranged on the same plane, The power receiving electrodes included in each of the plurality of transmission units are also arranged on the same plane. The wireless power transmission device according to claim 1 .

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