Wireless power transmission system

Abstract

To suppress the increase in output voltage when a power value to be wirelessly transmitted differs depending on the area of a power transmission coil.SOLUTION: A wireless power transmission system includes a transmitting coil and a receiving coil arranged opposite each other and movable relative to each other, and the transmitting coil has a structure in which a conductor is wound uniformly across the entire area in a direction facing the receiving coil, and has a first area that wirelessly transmits power in a first power value range and a second area that wirelessly transmits power in a second power value range, and the maximum value of the second power value range is smaller than the maximum value of the first power value range, and the coupling coefficient between the transmitting coil and the receiving coil when the receiving coil is located in the second area of the transmitting coil is smaller than the coupling coefficient between the transmitting coil and the receiving coil when the receiving coil is located in the first area of the transmitting coil.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a wireless power transfer system. [Background technology]

[0002] In recent years, wireless power transmission systems that wirelessly supply power to moving objects have been researched and developed. For example, Patent Document 1 discloses a printer that uses a long, narrow power transmission coil to wirelessly supply power to a sliding ink cartridge. By transmitting power wirelessly, power lines that wear out due to movement are eliminated, improving product quality. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-14056 Summary of the Invention [Problem to be solved by the invention]

[0004] If the power value required by the load device varies depending on the position of the moving object, the smaller the power value, the higher the output voltage of the power receiving circuit, which requires a high withstand voltage for the semiconductors inside the subsequent constant voltage circuit, resulting in a larger circuit size.

[0005] An object of the present disclosure is to suppress an increase in output voltage when the value of wirelessly transmitted power differs depending on the area of ​​the power transmitting coil. [Means for solving the problem]

[0006] The wireless power transmission system has a transmitting coil and a receiving coil arranged opposite each other and movable relative to each other, the transmitting coil having a structure in which a conductor is wound uniformly across the entire area in a direction facing the receiving coil, the transmitting coil having a first area that wirelessly transmits power in a first power value range and a second area that wirelessly transmits power in a second power value range, the maximum value of the second power value range being smaller than the maximum value of the first power value range, and the coupling coefficient between the transmitting coil and the receiving coil when the receiving coil is located in the second area of ​​the transmitting coil being smaller than the coupling coefficient between the transmitting coil and the receiving coil when the receiving coil is located in the first area of ​​the transmitting coil. [Effects of the Invention]

[0007] According to the present disclosure, when the value of the power to be wirelessly transmitted differs depending on the region of the power transmitting coil, an increase in output voltage can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of a wireless power transmission system. [Figure 2] FIG. 2 is a diagram illustrating an example of a coil configuration. [Figure 3] 10A and 10B are diagrams illustrating changes in the coupling coefficient between the coils and the output voltage of the power receiving circuit. [Figure 4] 10 is a diagram illustrating the relationship between the output power and the output voltage of the power receiving circuit. FIG. [Figure 5] FIG. 2 is a diagram illustrating an example of a coil configuration. [Figure 6] 10A and 10B are diagrams illustrating changes in the coupling coefficient between the coils and the output voltage of the power receiving circuit. [Figure 7] 10 is a diagram illustrating the relationship between the output power and the output voltage of the power receiving circuit. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) 1 shows an example of the configuration of a wireless power transmission system 100 according to the first embodiment. The wireless power transmission system 100 includes a fixed unit 101 and a moving unit .

[0010] The fixed unit 101 has a power transmitting circuit 104 and a power transmitting coil 105. The moving unit 102 has a power receiving coil 106, a power receiving circuit 107, and a constant voltage circuit 108.

[0011] The power transmitting circuit 104 converts the DC voltage supplied from the power supply device 103 into an AC voltage, and applies the AC voltage to the power transmitting coil 105 .

[0012] When an AC voltage is applied to the power transmitting coil 105, an AC current flows and a magnetic field is generated.

[0013] The power receiving coil 106 receives the magnetic field generated by the power transmitting coil 105 and generates an alternating current.

[0014] The power receiving circuit 107 converts the AC current of the power receiving coil 106 into a DC current, and outputs the DC voltage to the constant voltage circuit 108 .

[0015] The constant voltage circuit 108 converts the fluctuating DC voltage of the power receiving circuit 107 into a constant DC voltage, and supplies the DC voltage to the load device 109 .

[0016] The load device 109 has a plurality of functions, and the function that operates varies depending on the position of the moving part 102. The load device 109 receives a DC voltage from the constant voltage circuit 108, and requires different power values ​​for each function.

[0017] 2(a) and 2(b) show examples of the configuration of the power transmitting coil 105 and the power receiving coil 106. Fig. 2(a) shows the configuration of the power transmitting coil 105 and the power receiving coil 106 on their opposing surfaces.

[0018] The power receiving coil 106 moves parallel to the vertical direction while maintaining a constant distance from the power transmitting coil 105. The power transmitting coil 105 and the power receiving coil 106 are movable relative to each other. The dimension of the power transmitting coil 105 is set to be sufficiently longer than the dimension of the power receiving coil 106 in the direction of movement of the power transmitting coil 105.

[0019] The power value required by the load device 109 varies depending on the position of the moving part 102, and an area requiring power in the high power value range is designated as A1, and an area requiring power in the low power value range is designated as A2.

[0020] The power transmitting coil 105 has an area A1 and an area A2. The area A1 is an area for wirelessly transmitting power in a high power range. The area A2 is an area for wirelessly transmitting power in a low power range.

[0021] The conductor width W1 of the power transmitting coil 105 in the region A1 is equal to the conductor width W2 of the power transmitting coil 105 in the region A2. The separation distance L2 between the left and right conductors of the power transmitting coil 105 in the region A2 is shorter than the separation distance L1 between the left and right conductors of the power transmitting coil 105 in the region A1.

[0022] On the surface of the power transmitting coil 105 facing the power receiving coil 106, the separation distance L2 between the multiple conductors of the power transmitting coil 105 in the area A2 is shorter than the separation distance L1 between the multiple conductors of the power transmitting coil 105 in the area A1.

[0023] 2(b) shows the configuration when viewed from a direction perpendicular to the opposing surfaces of the transmitting coil 105 and the receiving coil 106. The transmitting coil 105 and the receiving coil 106 are arranged facing each other. Each of the transmitting coil 105 and the receiving coil 106 has a structure in which a conductor is wound uniformly over the entire area in the opposing direction.

[0024] Furthermore, magnetic materials 201 and 202 are arranged to increase the coupling coefficient between the transmitting coil 105 and the receiving coil 106. Each of the magnetic materials 201 and 202 is larger than the dimensions of the transmitting coil 105 and the receiving coil 106 that it contacts, and has a uniform thickness.

[0025] Power transmitting coil 105 is in contact with magnetic body 201 in the direction opposite to the direction in which it faces power receiving coil 106. Power receiving coil 106 is in contact with magnetic body 202 in the direction opposite to the direction in which it faces power transmitting coil 105.

[0026] 3 shows the change in the coupling coefficient K between the transmitting coil 105 and the receiving coil 106, and the output voltage Vo of the receiving circuit 107. The coupling coefficient K in each of the regions A1 and A2 changes according to the separation distance L2 shown in FIG. 2(a), and the output voltage Vo fluctuates when the range of the power value Po in each of the regions A1 and A2 changes from 600 W to 200 W and from 200 W to 10 W, respectively.

[0027] The coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 when the power receiving coil 106 is in the area A2 of the power transmitting coil 105 is smaller than the coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 when the power receiving coil 106 is in the area A1 of the power transmitting coil 105.

[0028] When power receiving coil 106 is located in area A2 of power transmitting coil 105, coupling coefficient K between power transmitting coil 105 and power receiving coil 106 decreases as separation distance L2 between multiple conductors of power transmitting coil 105 in area A2 decreases.

[0029] FIG. 4 shows the relationship between the output power Po and the output voltage Vo of the power receiving circuit 107 when the separation distance L2 is 6 mm and L2 is 10 mm in FIG.

[0030] By reducing the separation distance L2, the coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 in the area A2 can be reduced more than in the area A1, thereby reducing the fluctuation range of the output voltage Vo in the area A2.

[0031] In order to reduce the withstand voltage of the semiconductors that make up the constant voltage circuit 108, it is desirable that the output voltage Vo (P1 shown in FIG. 4) at a power value of 10 W in region A2 be lower than the output voltage Vo (P2 shown in FIG. 4) at a power value of 200 W in region A1.

[0032] The same effect can be achieved when the maximum value of the range of power values ​​Po in area A2 is smaller than the maximum value of the range of power values ​​Po in area A1.

[0033] As described above, according to the first embodiment, the conductor width W1 of the power transmitting coil 105 in the region A1 is equal to the conductor width W2 of the power transmitting coil 105 in the region A2. In this case, by reducing the separation distance L2 in the region A2, the coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 in the region A2 can be reduced compared to the region A1, thereby narrowing the range of the output voltage Vo in the region A2.

[0034] In addition, by making the thickness of the magnetic body 201 in the area A2 thinner than the thickness of the magnetic body 201 in the area A1, it is possible to reduce the coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 in the area A2 compared to the area A1.

[0035] When power receiving coil 106 is present in area A2 of power transmitting coil 105, coupling coefficient K between power transmitting coil 105 and power receiving coil 106 decreases as the thickness of magnetic body 201 in area A2 decreases.

[0036] (Second embodiment) The configuration of the wireless power transmission system 100 according to the second embodiment is similar to that of the first embodiment.

[0037] 5(a) and 5(b) show configuration examples of the power transmitting coil 105 and the power receiving coil 106. Fig. 5(a) shows a configuration example of the power transmitting coil 105 and the power receiving coil 106 on their opposing surfaces.

[0038] The power receiving coil 106 moves in parallel in the vertical direction while maintaining a constant distance from the power transmitting coil 105. The dimension of the power transmitting coil 105 is set to be sufficiently longer than the dimension of the power receiving coil 106 in the direction of movement of the power receiving coil 106.

[0039] The power value required by the load device 109 varies depending on the position of the moving part 102, and an area requiring power in the high power value range is designated as A1, and an area requiring power in the low power value range is designated as A2.

[0040] The conductor width W1 of the power transmitting coil 105 in the region A1 is different from the conductor width W2 of the power transmitting coil 105 in the region A2. The separation distance L2 between the left and right conductors of the power transmitting coil 105 in the region A2 is shorter than the separation distance L1 between the left and right conductors of the power transmitting coil 105 in the region A1.

[0041] On the surface of the power transmitting coil 105 facing the power receiving coil 106, the separation distance L2 between the multiple conductors of the power transmitting coil 105 in the area A2 is shorter than the separation distance L1 between the multiple conductors of the power transmitting coil 105 in the area A1.

[0042] 5(b) shows an example of the configuration when viewed from a direction perpendicular to the opposing surfaces of the power transmitting coil 105 and the power receiving coil 106. Each of the power transmitting coil 105 and the power receiving coil 106 has a structure in which a conductor is wound uniformly in the opposing direction over the entire area. In addition, magnetic materials 201 and 202 are arranged to increase the coupling coefficient between the power transmitting coil 105 and the power receiving coil 106. Each of the magnetic materials 201 and 202 is larger than the dimensions of the power transmitting coil 105 and the power receiving coil 106 that it contacts, and has a uniform thickness.

[0043] 6 shows the change in the coupling coefficient K between the transmitting coil 105 and the receiving coil 106 and the output voltage Vo of the receiving circuit 107. The coupling coefficient K in each of the regions A1 and A2 changes according to the separation distance L2 shown in FIG. 5(a), and the output voltage Vo fluctuates when the range of the power value Po in each of the regions A1 and A2 changes from 600 W to 200 W and from 200 W to 10 W, respectively.

[0044] The coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 when the power receiving coil 106 is in the area A2 of the power transmitting coil 105 is smaller than the coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 when the power receiving coil 106 is in the area A1 of the power transmitting coil 105.

[0045] When power receiving coil 106 is located in area A2 of power transmitting coil 105, coupling coefficient K between power transmitting coil 105 and power receiving coil 106 decreases as separation distance L2 between multiple conductors of power transmitting coil 105 in area A2 decreases.

[0046] Fig. 7 shows the relationship between the output power Po and the output voltage Vo of the power receiving circuit 107 when the separation distance L2 is 6 mm and L2 is 10 mm as shown in Fig. 6. By reducing the separation distance L2, the coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 in the region A2 can be reduced more than in the region A1, thereby reducing the fluctuation range of the output voltage Vo in the region A2.

[0047] In order to reduce the withstand voltage of the semiconductors that make up the constant voltage circuit 108, it is desirable that the output voltage Vo (P1 shown in FIG. 7) at a power value of 10 W in region A2 be lower than the output voltage Vo (P2 shown in FIG. 7) at a power value of 200 W in region A1.

[0048] The same effect can be achieved when the maximum value of the range of power values ​​Po in area A2 is smaller than the maximum value of the range of power values ​​Po in area A1.

[0049] As described above, according to the second embodiment, the conductor width W1 of the power transmitting coil 105 in the region A1 is different from the conductor width W2 of the power transmitting coil 105 in the region A2. In this case, by reducing the separation distance L2 in the region A2, the coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 in the region A2 can be reduced more than in the region A1, thereby narrowing the range of the output voltage Vo in the region A2.

[0050] In addition, by making the thickness of the magnetic body 201 in the area A2 thinner than the thickness of the magnetic body 201 in the area A1, it is possible to reduce the coupling coefficient K between the power transmitting coil 105 and the power receiving coil 106 in the area A2 compared to the area A1.

[0051] When power receiving coil 106 is present in area A2 of power transmitting coil 105, coupling coefficient K between power transmitting coil 105 and power receiving coil 106 decreases as the thickness of magnetic body 201 in area A2 decreases.

[0052] As described above, according to the first and second embodiments, even if the power value Po required by the load device 109 varies depending on the position of the moving body of the power receiving coil 106, an increase in the output voltage Vo of the power receiving circuit 107 can be suppressed.

[0053] It should be noted that the above-described embodiments merely illustrate specific examples of implementing the present disclosure, and the technical scope of the present disclosure should not be construed as being limited by these embodiments. In other words, the present disclosure can be implemented in various forms without departing from its technical concept or main features.

[0054] The disclosure of this embodiment includes the following configuration. (Configuration 1) a power transmitting coil and a power receiving coil that are arranged opposite to each other and are relatively movable; The power transmission coil is The conductor is wound uniformly over the entire area in a direction facing the receiving coil, a first area in which power within a first power value range is wirelessly transmitted; a second area in which power in a second power value range is wirelessly transmitted; the maximum value of the second power value range is smaller than the maximum value of the first power value range; A wireless power transmission system characterized in that a coupling coefficient between the transmitting coil and the receiving coil when the receiving coil is located in the second region of the transmitting coil is smaller than a coupling coefficient between the transmitting coil and the receiving coil when the receiving coil is located in the first region of the transmitting coil. (Configuration 2) 2. The wireless power transmission system according to configuration 1, wherein the size of the power transmitting coil is longer than the size of the power receiving coil in the direction of the movement. (Configuration 3) 3. The wireless power transmission system according to claim 1, wherein the power transmitting coil is in contact with a magnetic body in a direction opposite to the direction in which the power transmitting coil faces the power receiving coil. (Configuration 4) The wireless power transmission system according to any one of configurations 1 to 3, characterized in that on a surface of the transmitting coil facing the receiving coil, the spacing between the multiple conductors of the transmitting coil in the second region is shorter than the spacing between the multiple conductors of the transmitting coil in the first region. (Configuration 5) The wireless power transmission system according to any one of configurations 1 to 4, characterized in that when the receiving coil is located in the second region of the transmitting coil, the coupling coefficient between the transmitting coil and the receiving coil becomes smaller as the separation distance between the multiple conductors of the transmitting coil in the second region becomes shorter. (Configuration 6) 4. The wireless power transmission system according to configuration 3, wherein the thickness of the magnetic material in the second region is thinner than the thickness of the magnetic material in the first region. (Configuration 7) The wireless power transmission system according to configuration 3 or 6, wherein when the receiving coil is located in the second region of the transmitting coil, the coupling coefficient between the transmitting coil and the receiving coil becomes smaller as the thickness of the magnetic material in the second region becomes thinner. (Configuration 8) The wireless power transmission system according to any one of configurations 1 to 7, wherein the conductor width of the power transmission coil in the first region and the conductor width of the power transmission coil in the second region are equal to each other. (Configuration 9) 8. The wireless power transmission system according to any one of configurations 1 to 7, wherein the conductor width of the power transmission coil in the first region and the conductor width of the power transmission coil in the second region are different from each other. (Configuration 10) 10. The wireless power transmission system according to any one of configurations 1 to 9, further comprising a power transmission circuit that converts a DC voltage into an AC voltage and applies the AC voltage to the power transmission coil. (Configuration 11) 11. The wireless power transmission system according to configuration 10, further comprising a power receiving circuit that converts the AC current of the power receiving coil into a DC current. (Configuration 12) 12. The wireless power transmission system according to configuration 11, further comprising a constant voltage circuit that converts the voltage of the power receiving circuit into a constant DC voltage. [Explanation of symbols]

[0055] 100 Wireless power transmission system, 101 Fixed part, 102 Moving part, 103 Power supply device, 104 Power transmission circuit, 105 Power transmission coil, 106 Power receiving coil, 107 Power receiving circuit, 108 Constant voltage circuit, 109 Load device, 201, 202 Magnetic material

Claims

1. a power transmitting coil and a power receiving coil that are arranged opposite to each other and are relatively movable; The power transmission coil is The conductor is wound uniformly over the entire area in a direction facing the receiving coil, a first area in which power within a first power value range is wirelessly transmitted; a second area in which power in a second power value range is wirelessly transmitted; the maximum value of the second power value range is smaller than the maximum value of the first power value range; A wireless power transmission system characterized in that the coupling coefficient between the transmitting coil and the receiving coil when the receiving coil is located in the second region of the transmitting coil is smaller than the coupling coefficient between the transmitting coil and the receiving coil when the receiving coil is located in the first region of the transmitting coil.

2. The wireless power transmission system according to claim 1 , wherein the power transmitting coil has a dimension longer than the dimension of the power receiving coil in the direction of the movement.

3. The wireless power transmission system according to claim 1 , wherein the power transmitting coil is in contact with the magnetic body in a direction opposite to a direction in which the power transmitting coil faces the power receiving coil.

4. 2. The wireless power transmission system according to claim 1, wherein, on a surface of the transmitting coil facing the receiving coil, a spacing between the multiple conductors of the transmitting coil in the second region is shorter than a spacing between the multiple conductors of the transmitting coil in the first region.

5. 2. The wireless power transmission system according to claim 1, wherein when the receiving coil is located in the second region of the transmitting coil, the coupling coefficient between the transmitting coil and the receiving coil decreases as the separation distance between the multiple conductors of the transmitting coil in the second region decreases.

6. The wireless power transmission system according to claim 3 , wherein the thickness of the magnetic material in the second region is thinner than the thickness of the magnetic material in the first region.

7. 4. The wireless power transmission system according to claim 3, wherein when the receiving coil is located in the second region of the transmitting coil, the coupling coefficient between the transmitting coil and the receiving coil becomes smaller as the thickness of the magnetic material in the second region becomes thinner.

8. The wireless power transmission system according to claim 1 , wherein a conductor width of the power transmitting coil in the first region and a conductor width of the power transmitting coil in the second region are equal to each other.

9. The wireless power transmission system according to claim 1 , wherein a conductor width of the power transmitting coil in the first region and a conductor width of the power transmitting coil in the second region are different from each other.

10. 2. The wireless power transmission system according to claim 1, further comprising a power transmission circuit that converts a DC voltage into an AC voltage and applies the AC voltage to the power transmission coil.

11. 11. The wireless power transmission system according to claim 10, further comprising a power receiving circuit that converts the AC current of the power receiving coil into a DC current.

12. 12. The wireless power transmission system according to claim 11, further comprising a constant voltage circuit that converts the voltage of the power receiving circuit into a constant DC voltage.

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