A wireless charging system magnetic coupling mechanism for generating a uniform magnetic field in space and a parameter optimization method thereof

Abstract

This invention belongs to the field of wireless power transmission and discloses a coupling mechanism for a wireless power transmission system that generates a uniform magnetic field in space. The coupling mechanism includes a transmitting coil and a receiving coil. The transmitting coil includes a stepped transmitting coil and a combined anti-series coil. The stepped transmitting coil is composed of multiple stepped transmitting coil units. Each rectangular stepped transmitting coil unit includes n horizontal platforms and m vertical platforms, where n = 2m + 1. The combined anti-series coil is composed of at least one set of first coil units connected in series. The first coil unit of the combined anti-series coil has a polygonal structure, and the number of sides of the first coil unit is the same as the number of stepped transmitting coil units. This invention utilizes the design of placing the combined anti-series coil inside the stepped transmitting coil. By utilizing the principle of magnetic field superposition, the combination of the stepped transmitting coil and the combined anti-series coil can compensate for the weaker magnetic field in the middle of the stepped coil.

Description

Technical Field

[0001] This invention belongs to the technical field of wireless power transmission, and more specifically, relates to a coupling mechanism for a wireless power transmission system that generates a uniform magnetic field in space and a method for optimizing its parameters. Background Technology

[0002] With economic development, the exploration of the ocean and the utilization of marine resources have become popular research directions in recent years. Underwater vehicles are core equipment for exploring the ocean and developing marine resources. Currently, underwater vehicles of various shapes have been developed to adapt to different working environments. However, energy issues have always been a major factor restricting the long-term continuous operation of underwater vehicles in the ocean. Wireless power transmission technology, as a new type of power transmission method, breaks the inherent mode of traditional wired power transmission, completely isolating the electronic devices at the transmitting and receiving ends, and has great development potential, especially in underwater applications.

[0003] Electromagnetic coupling mechanisms are core components of wireless power transmission systems, playing a crucial role in system output power and transmission efficiency. The design of the coupling mechanism must ensure compatibility with the underwater vehicle's external structure, and guarantee the stability of its parameters should misalignment occur. This requires the transmitting coil of the coupler to generate a uniform magnetic field in space, ensuring that the receiving coil can stably receive energy at all locations within space.

[0004] The marine environment contains microorganisms and algae that easily adhere to object surfaces. Due to prolonged underwater operation, these microorganisms can accumulate on the hull of underwater vehicles, potentially causing misalignment in various directions, including lateral, vertical, and rotational angles, during wireless charging. The presence of these microorganisms increases the transmission distance of the coupling mechanism and significantly reduces system transmission efficiency. Therefore, there is an urgent need to design a coupler that can generate a uniform magnetic field in space to ensure the coupling mechanism can withstand misalignment in all directions, thereby achieving stable and efficient transmission.

[0005] Currently, some electromagnetic coupling mechanisms exist that can generate uniform magnetic fields, but most of them are designed for underwater vehicles with rotating structures. Their characteristic is that they can generate uniform magnetic fields in a specific direction in space, but the range of the generated uniform magnetic field is limited, and they only have a certain resistance to displacement in a specific direction, which cannot meet the operating environment of planar underwater vehicles. This limits the development of underwater wireless charging.

[0006] To address the lateral, vertical, and rotational deviations experienced by planar underwater vehicles, a coupling mechanism for an underwater wireless power transmission system with uniform magnetic field characteristics needs to be designed. This mechanism should be able to generate a uniform magnetic field over a large area of ​​space, ensuring efficient and stable operation. Furthermore, the specific parameters of the coupling mechanism should be optimized to achieve the best uniform magnetic field effect. Summary of the Invention

[0007] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a coupling mechanism and parameter optimization method for a wireless power transmission system that generates a uniform magnetic field in space. The transmitting coil of the coupling mechanism is composed of a stepped transmitting coil and a combined anti-series coil, with the stepped transmitting coil and the combined coil connected in reverse series. The combination of the stepped transmitting coil and the combined anti-series coil allows their magnetic fields to compensate for each other, thereby solving the technical problem of generating a uniform magnetic field over a large area in space. Based on the coupling mechanism of the wireless power transmission system that generates a uniform magnetic field in space provided by this invention, a method for optimizing the structural parameters of the transmitting coil of the coupling mechanism is provided, enabling the coupling mechanism to achieve a uniform magnetic field over a large area in space, thereby achieving the ability to resist omnidirectional positional shifts in all directions, including lateral, vertical, and tilting directions.

[0008] To achieve the above objectives, according to one aspect of the present invention, a wireless power transmission system coupling mechanism for generating a uniform magnetic field in space is provided, the coupling mechanism comprising a transmitting coil and a receiving coil;

[0009] It should be noted that the transmitting coil and the receiving coil are independent mechanisms. During use, the transmitting coil and the receiving coil work together to achieve the purpose of energy transmission.

[0010] Furthermore, the transmitting coil includes a stepped transmitting coil and a combined anti-series coil;

[0011] The stepped transmitting coil is composed of multiple stepped transmitting coil units;

[0012] The stepped transmitting coil unit is rectangular and includes a horizontal platform and a vertical platform.

[0013] Furthermore, the rectangular stepped coil unit includes n horizontal platforms and m vertical platforms, where n = 2m + 1, and m is a positive integer greater than 0.

[0014] Furthermore, the rectangular stepped vertical platforms are all of equal height;

[0015] Furthermore, the rectangular stepped next horizontal platform is connected to the previous horizontal platform end to end by a vertical platform.

[0016] It should be noted that the rectangular stepped lower horizontal platform of the present invention is connected to the upper horizontal platform end to end through a vertical platform, so that the rectangular stepped structure is a symmetrical stepped shape. In addition, the upper and lower positions of the upper and lower horizontal platforms used here are relative positions and do not refer to the specific number of platforms.

[0017] In some embodiments, the stepped transmitting coil consists of at least four stepped transmitting coil units;

[0018] The at least four stepped transmitting coil units form a closed stepped transmitting coil, thereby creating a closed loop in the stepped transmitting coil.

[0019] Furthermore, the number of turns of the stepped transmitting coil is N1;

[0020] In other embodiments, the combined anti-series coil is composed of multiple sets of first coil units connected in series, with each set of coil units connected in reverse order, that is, the current flows in opposite directions in two adjacent coil units.

[0021] It should be noted that the first coil units are on the same plane, and the sizes of the first coil units are not necessarily equal. For example, the two first coil units can be of different sizes and can form a centrally symmetrical structure.

[0022] The first coil unit of the combined anti-series coil has a polygonal structure, and the number of sides of the first coil unit is the same as the number of the stepped transmitting coil units.

[0023] Furthermore, the combined anti-series coil is located within the closed-loop space formed by the stepped transmitting coil;

[0024] Furthermore, the combined anti-series coil is aligned with the center of the stepped transmitting coil;

[0025] Preferably, the stepped transmitting coil is composed of four stepped transmitting coil units;

[0026] The first coil unit of the combined anti-series coil has a quadrilateral structure.

[0027] Preferably, the first coil unit of the combined anti-series coil has a square structure;

[0028] More preferably, the combined anti-series coil consists of three sets of square structure coils;

[0029] The stepped transmitting coil provided by the present invention, because it includes a stepped transmitting coil unit, can generate a large-scale uniform magnetic field region along the vertical platform direction by increasing the height of the vertical platform of the stepped transmitting coil unit by a small distance.

[0030] Furthermore, the magnetic fields generated by the stepped transmitting coils at the adjacent chain wires of the two stepped transmitting coil units are superimposed at this point, and the magnetic field strength generated at the adjacent chain wires will be much stronger than the magnetic field in the middle region (closed region).

[0031] Furthermore, the combined anti-series coil can generate a magnetic field that is strong in the middle region and weak in the outer region.

[0032] This invention is based on the design of the transmitting coil structure. By combining a stepped transmitting coil with a combined anti-series coil, the weak magnetic field in the middle of the stepped coil can be compensated.

[0033] According to another aspect of the present invention, a design method for a coupling mechanism of a wireless power transfer system that generates a uniform magnetic field in space is provided, comprising the following steps:

[0034] S1: Adjust the n-segment horizontal platform and m-segment vertical platform of the stepped transmitting coil unit and the number of turns N1 of the stepped transmitting coil. Calculate the magnetic field strength of the stepped transmitting coil according to the formula, and optimize the n-segment horizontal platform, m-segment vertical platform and the number of turns N1 so that the minimum value of the magnetic field Bz at the height z of the stepped transmitting coil is greater than 50% of the maximum value of Bz.

[0035] S2: Based on the optimized n-segment horizontal platform and m-segment vertical platform and the number of turns N1, set at least one first coil unit of anti-series coil, calculate the magnetic field strength of the stepped transmitting coil according to the formula, and adjust the number of first coil units so that the minimum value of the magnetic field Bz at the height direction z of the stepped transmitting coil is greater than 95% of the maximum value of Bz.

[0036] Preferably, the present invention also provides a wireless power transmission system coupling mechanism that generates a uniform magnetic field in space, the coupling mechanism comprising a transmitting coil and a receiving coil;

[0037] The transmitting coil includes a stepped transmitting coil and a combined anti-series coil;

[0038] The stepped transmitting coil is composed of four stepped transmitting coil units; the combined anti-series coil is composed of three sets of square structure first coil units; the combined anti-series coil is located within the closed loop space formed by the stepped transmitting coil; and the combined anti-series coil is aligned with the center of the stepped transmitting coil.

[0039] The rectangular stepped coil unit includes n horizontal platforms and m vertical platforms, where n = 2m + 1, and m is a positive integer greater than 0; the number of turns of the stepped transmitting coil is N1.

[0040] Furthermore, as a preferred embodiment, the present invention provides a design method for a coupling mechanism of a wireless power transfer system that generates a uniform magnetic field in space, comprising the following steps:

[0041] S1: Adjust the n-segment horizontal platform and m-segment vertical platform of the stepped transmitting coil unit and the number of turns N1 of the stepped transmitting coil. Calculate the magnetic field strength of the stepped transmitting coil according to the formula, and optimize the n-segment horizontal platform, m-segment vertical platform and the number of turns N1 so that the minimum value of the magnetic field Bz at the height z of the stepped transmitting coil is greater than 50% of the maximum value of Bz.

[0042] S2: Based on the optimized n-segment horizontal platform and m-segment vertical platform and the number of turns N1, the first coil unit of the anti-series coil is used to uniformly distribute the magnetic field. The magnetic field strength of the stepped transmitting coil is calculated according to the formula, so that the minimum value of the magnetic field Bz at the height direction z of the stepped transmitting coil is greater than 65% of the maximum value of Bz.

[0043] S3: Based on the first coil unit of the anti-series coil described in step S2, which is used to uniformly distribute the magnetic field, a second coil unit of the anti-series coil is further set to uniformly distribute the magnetic field. The magnetic field strength of the stepped transmitting coil is calculated according to the formula, so that the minimum value of the magnetic field Bz at the height z of the stepped transmitting coil is greater than 80% of the maximum value of Bz.

[0044] S4: Based on the first and second first coil unit turns of the anti-series coil in step S3, which are used to uniformly distribute the magnetic field, a third first coil unit turn of the anti-series coil is further set to uniformly distribute the magnetic field. The magnetic field strength of the stepped transmitting coil is calculated according to the formula, so that the minimum value of the magnetic field Bz at the height z of the stepped transmitting coil is greater than 95% of the maximum value of Bz.

[0045] Compared with the prior art, the present invention has the following advantages based on the above-described technical solutions conceived in this invention.

[0046] Beneficial effects:

[0047] This invention combines a stepped transmitting coil with an anti-series coil to form the transmitting coil of a coupler, allowing the transmitting coil in the coupling mechanism to generate magnetic fields over a large spatial area. The magnetic fields generated by the stepped transmitting coil at adjacent chain wires of two stepped transmitting coil units are superimposed at these points, resulting in a much stronger magnetic field at the adjacent chain wires than in the central (closed) region. The combined anti-series coil can generate a magnetic field that is strong in the central (closed) region and weak in the outer region. By placing the combined anti-series coil inside the stepped transmitting coil, and utilizing the principle of magnetic field superposition, the combination of the stepped transmitting coil and the combined anti-series coil can compensate for the weaker central magnetic field of the stepped coil.

[0048] In addition, the stepped transmitting coil unit of the transmitting coil provided by the present invention increases the magnetic field strength of the transmitting coil in the height direction of the stepped transmitting coil by a small height. At the same time, the combination with the anti-series coil inside the transmitting coil optimizes the specific parameters of the stepped transmitting coil and the anti-series coil, so that the coupling mechanism can achieve a uniform magnetic field in a large spatial range, thereby achieving the ability to resist omnidirectional position shift in various directions such as lateral, vertical, and tilt. Attached Figure Description

[0049] The present application will be described in further detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the present application.

[0050] Figure 1 This is a detailed schematic diagram of the stepped coil as an example of the present invention;

[0051] Figure 2 These are magnetic field distribution diagrams of the stepped coil unit of the present invention with different numbers of vertical platforms, wherein, in Figure (a) m=1, Figure (b) m=2, Figure (c) m=3, and Figure (d) m=4;

[0052] Figure 3 These are structural diagrams of the stepped coil transmitting coil of the present invention: (a) top view and (b) cross-sectional view.

[0053] Figure 4 This is a flowchart illustrating the optimization of coupling mechanism parameters in an example of the present invention;

[0054] Figure 5 This is a schematic diagram of the coupling mechanism of the present invention under different offset conditions;

[0055] Figure 6The following are the mutual inductance distribution diagrams of the coupling mechanism of the present invention under different transmission distances: (a) H=20mm, (b) H=30mm, (c) H=40mm, (d) H=50mm, (e) H=60mm, and (f) H=70mm.

[0056] Figure 7 The following are the mutual inductance distribution diagrams of the coupling mechanism of the present invention under different rotation angles: (a) θ = 5°, (b) θ = 10°, (c) θ = 15°, and (d) θ = 20°. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0058] Figure 1 This is a detailed schematic diagram of a stepped transmitting coil. This embodiment includes a stepped transmitting coil and a combined anti-series coil. The stepped transmitting coil consists of four stepped transmitting coil units. The combined anti-series coil consists of three sets of square-structured first coil units. The combined anti-series coil is located within the closed-loop space formed by the stepped transmitting coil, and its center is aligned with the center of the stepped transmitting coil. The rectangular stepped coil unit includes n horizontal platforms and m vertical platforms, where n = 2m + 1, and m is a positive integer greater than 0. A scheme with N1 turns for the stepped transmitting coil is discussed, and the relevant coordinates are shown in the diagram. The coordinate axis is at the center of the stepped transmitting coil, and P is any point in space. The magnetic field strength at point P is the vector superposition generated by each coil segment in the stepped transmitting coil.

[0059] According to the Biot-Savart law, the magnetic field strength produced by the current element at point P is:

[0060]

[0061] Where μ0 is the permeability in vacuum, I is the current flowing through the conductor, and r is the distance from point P to the conductor segment. For the corresponding vector, the magnetic induction intensity generated by the conductor segment at point P is the sum of the induced magnetic fields generated by the current elements.

[0062] exist Figure 1In the diagram, S is the charging plane. At point H above the stepped transmitting coil, the rectangular stepped transmitting coil contains four stepped transmitting coil units, and the four stepped transmitting coil units have equal side lengths. The four stepped transmitting coil units are connected to form a closed structure, presenting an axially symmetrical structure.

[0063] Therefore, the following analysis focuses only on one of the stepped transmitting coil units. The stepped transmitting coil unit contains n transverse platforms, each with a length of l. 11 It contains m vertical platform segments in the vertical direction;

[0064] Where n = 2m + 1, and m takes the value of a positive integer greater than 0;

[0065] The vertical platform height is set to hmm, and the horizontal platform length is set to l. 11 mm; the magnetic field distribution above the transmitting coil is affected by the stepped transmitting coil unit structure. The vertical platform height of the rectangular stepped transmitting coil unit provided by the present invention is equal; and the next horizontal platform of the rectangular stepped structure is connected to the previous horizontal platform through the vertical platform (or platform) end to end; the number of turns of the rectangular stepped coil is N1.

[0066] like Figure 1 As shown, the rectangular stepped transmitting coil unit of the stepped transmitting coil has horizontal conductor segments AB, CD, EF…NQ…RS,TU. The magnetic induction intensity generated at point P can be calculated by formula (2).

[0067]

[0068] The magnetic flux density at point P can be decomposed into a horizontal component parallel to the charging plane and a vertical component perpendicular to the charging plane. In the proposed rectangular stepped coil, the vertical component of the magnetic flux density is the main factor affecting the power transmission efficiency.

[0069] The angles between the charging plane S and the charging plane are α1, α2…α n-1 ,α n ,

[0070]

[0071] Therefore, the vertical magnetic field component generated at point P by the horizontal conductor segment is:

[0072]

[0073] The magnetic field strength at point P also includes the perpendicular component to the conductor segments BC, DE, HJ…KL…QR,ST, which can be calculated by (5).

[0074]

[0075] The angle between the object and the charging plane S is β1, β2…β n-1 ,β n ,

[0076]

[0077] Therefore, the vertical magnetic field component generated at point P by the vertical conductor segment is:

[0078]

[0079] The magnetic field strength at point P is the sum of the magnetic induction intensity produced by the horizontal line segment and the magnetic induction intensity produced by the vertical line segment, and can be calculated by (8):

[0080]

[0081] The magnetic field distribution at the same height with different numbers of vertical platforms is calculated using formulas (4), (7), and (8), as follows: Figure 2 As shown, with the increase of the number of vertical platforms, the magnetic field strength above the stepped transmitting coil is greatly improved, the peak magnetic field strength around the perimeter gradually decreases, and the magnetic field strength in the central concave region increases. Therefore, the stepped transmitting coil has good anti-offset performance.

[0082] However, due to the limitation of actual size, the number of steps cannot be increased indefinitely. As shown in Figures (2)(d), there is still a magnetic field depression area in the middle of the stepped coil. Therefore, it is necessary to use a rectangular coil connected in anti-series inside the stepped transmitting coil to even out the magnetic field generated by the stepped transmitting coil. The overall structure is shown in Figure (3). The combined anti-series coil is composed of three square first coil units connected in series. The center of the anti-series coil inside the stepped transmitting coil is aligned with the center of the stepped coil. The number of turns of the first coil unit in the first group of the anti-series coil is N2, the number of turns of the second coil unit in the second group is N3, and the number of turns of the second coil unit in the second group is N4. The distances between the anti-series coils are amm, bmm, and cmm, respectively.

[0083] Based on finite element theory analysis, parameters m, h, N1, N2, N3, and N4 need to be optimized sequentially. The optimization flowchart is as follows. Figure 4 As shown, the basic idea for optimization is as follows:

[0084] Step 1: First, optimize the parameters m, h, and N1. To obtain a uniform magnetic field, first set the first evaluation criterion to B. z Is the minimum value greater than B? z 50% of the maximum value.

[0085] Step 2: Then, the anti-series coil group 1 is used to even out B. zThe magnetic field distribution, the second evaluation criterion is B. z Is the minimum value greater than B? z 65% of the maximum value.

[0086] Step 3: Next, the anti-series coil group 2 is used to further homogenize B. z The magnetic field distribution, the third evaluation criterion is B. z Is the minimum value greater than B? z 80% of the maximum value.

[0087] Step 4, finally, the anti-series coil group 3 is used to achieve uniform B. z The magnetic field distribution, the third evaluation criterion is B. z Is the minimum value greater than B? z 95% of the maximum value.

[0088] The optimization results are shown in Table 1:

[0089]

[0090] The offset of the coupling mechanism is as follows Figure 5 As shown, the offset in the x-direction is Δx, the offset in the y-direction is Δy, the height offset is Δh, and the angle offset is , where:

[0091]

[0092] Figure 6 The diagram shows the mutual inductance distribution of the coupling mechanism at different transmission distances, where (a) H = 20 mm, (b) H = 30 mm, (c) H = 40 mm, (d) H = 50 mm, (e) H = 60 mm, and (f) H = 70 mm. At a maximum offset of 40%, the mutual inductance fluctuation is 20.2%, which is acceptable considering extreme offsets. The maximum mutual inductance increases from 45.35 μH to 49.1 μH and then decreases to 36.8 μH.

[0093] Figure 7 The figure shows the mutual inductance distribution of the coupling mechanism at different rotation angles. As can be seen from the figure, the maximum value of mutual inductance does not fluctuate much. During the rotation, half of the receiving coil will be close to the stepped transmitting coil, and the other part will be far away from the transmitting coil. Therefore, the mutual inductance of the two receiving coils complements each other and finally achieves a uniform distribution. Under the maximum offset condition, the change in mutual inductance is within 32.1%.

[0094] In summary, the combined stepped coil and anti-series coil proposed in this invention, used as the transmitting coil of the coupling mechanism, can effectively and significantly increase the area of ​​the uniform magnetic field in the spatial region, thereby achieving the anti-offset performance of the receiving coil in various directions such as lateral, vertical, and tilt. Furthermore, the specific parameters of the transmitting coil are optimized to better achieve a uniform magnetic field.

[0095] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A coupling mechanism for a wireless power transmission system that generates a uniform magnetic field in space, said coupling mechanism comprising a transmitting coil and a receiving coil, characterized in that, The transmitting coil includes a stepped transmitting coil and a combined anti-series coil; The stepped transmitting coil is composed of multiple stepped transmitting coil units; The stepped transmitting coil unit is rectangular and includes a horizontal platform and a vertical platform. The stepped transmitting coil unit includes n horizontal platforms and m vertical platforms, where n = 2m + 1, and m is a positive integer greater than 0. The stepped transmitting coil units form a closed stepped transmitting coil, thus creating a closed loop. The combined anti-series coil is composed of at least one set of first coil units connected in reverse series, such that the current flows in opposite directions in two adjacent coil units. The first coil unit of the combined anti-series coil has a polygonal structure, and the number of sides of the first coil unit is the same as the number of the stepped transmitting coil units. The combined anti-series coil is located within the closed-loop space formed by the stepped transmitting coil; The combined anti-series coil is aligned with the center of the stepped transmitting coil.

2. The wireless power transmission system coupling mechanism for generating a uniform magnetic field in space as described in claim 1, characterized in that, The rectangular stepped vertical platforms are all of equal height; The rectangular stepped lower horizontal platform is connected to the upper horizontal platform end to end by a vertical platform.

3. The wireless power transfer system coupling mechanism for generating a uniform magnetic field in space as described in claim 2, characterized in that, The stepped transmitting coil is composed of at least four stepped transmitting coil units; The at least four stepped transmitting coil units form a closed stepped transmitting coil, thereby creating a closed loop.

4. The coupling mechanism of a wireless power transmission system that generates a uniform magnetic field in space as described in claim 1, characterized in that, The stepped transmitting coil is composed of four stepped transmitting coil units; The first coil unit of the combined anti-series coil has a quadrilateral structure. The wireless power transmission system coupling mechanism consists of a stepped transmitting coil and a combined anti-series coil connected in reverse series.

5. The wireless power transmission system coupling mechanism for generating a uniform magnetic field in space as described in claim 4, characterized in that, The combined anti-series coil consists of three sets of square structure coils.

6. An optimization method for a wireless power transfer system coupling mechanism that generates a uniform magnetic field in space, applied to the coupling mechanism according to any one of claims 1-5, comprising the following steps: S1: Adjust the n horizontal platforms and m vertical platforms of the stepped transmitting coil unit, as well as the number of turns N1 of the stepped transmitting coil. Calculate the magnetic field strength of the stepped transmitting coil according to the formula, and optimize the n horizontal platforms, m vertical platforms, and the number of turns N1 to make the magnetic field B at the height z direction of the stepped transmitting coil... z The minimum value is greater than B. z 50% of the maximum value; S2: Based on the optimized n-segment horizontal platform and m-segment vertical platform and the number of turns N1, set at least one set of first coil units of the combined anti-series coil, calculate the magnetic field strength of the stepped transmitting coil according to the formula, and adjust the number of first coil units so that the magnetic field B at the height direction z of the stepped transmitting coil is such that... z The minimum value is greater than B. z 95% of the maximum value.

7. A design method for a coupling mechanism of a wireless power transfer system that generates a uniform magnetic field in space, applied to the coupling mechanism of claim 5, comprising the following steps: S1: Adjust the n horizontal platforms and m vertical platforms of the stepped transmitting coil unit, as well as the number of turns N1 of the stepped transmitting coil. Calculate the magnetic field strength of the stepped transmitting coil according to the formula, and optimize the n horizontal platforms, m vertical platforms, and the number of turns N1 to make the magnetic field B at the height z direction of the stepped transmitting coil... z The minimum value is greater than B. z 50% of the maximum value; S2: Based on the optimized n-segment horizontal platform and m-segment vertical platform and the number of turns N1, the first coil unit of the first group of the combined anti-series coil is used to uniformly distribute the magnetic field. The magnetic field strength of the stepped transmitting coil is calculated according to the formula, so that the magnetic field B at the height z direction of the stepped transmitting coil is... z The minimum value is greater than B. z 65% of the maximum value; S3: Based on the first group of first coil unit turns of the combined anti-series coil described in step S2, which are used to uniformly distribute the magnetic field, a second group of first coil unit turns of the combined anti-series coil are further set to uniformly distribute the magnetic field. The magnetic field strength of the stepped transmitting coil is calculated according to the formula, so that the magnetic field B at the height z direction of the stepped transmitting coil is... z The minimum value is greater than B. z 80% of the maximum value; S4: Based on the first and second groups of first coil unit turns of the combined anti-series coil in step S3, which are used to uniformly distribute the magnetic field, a third group of first coil unit turns of the combined anti-series coil is further set to uniformly distribute the magnetic field. The magnetic field strength of the stepped transmitting coil is calculated according to the formula, so that the magnetic field B at the height z direction of the stepped transmitting coil is... z The minimum value is greater than B. z 95% of the maximum value.

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