Multi-layer PCB-litz structure wireless power transmission coil and design method

Abstract

The present application relates to magnetic coupling resonance wireless power transmission technology, in particular to a multi-layer PCB-Litz structure wireless power transmission coil and a design method, the coil is composed of a plurality of printed circuit board conductive layers, a three-dimensional conductive path is formed by using a multi-layer planar spiral wiring and a cross-layer via interconnection, a transposed staggered wiring Litz structure conductor is formed, the cross-layer via is arranged on the conductor path according to equal spacing or periodic rules, and one-to-one transposed connection of the conductor in the multi-layer structure is realized. A high-frequency equivalent impedance modeling method is constructed, the three-dimensional structure is equivalent to a two-dimensional multi-branch coupling network, impedance mapping and accumulation are carried out through differential unit segmentation modeling and combination of transposition relationship, and a via parasitic parameter correction model is introduced. The multi-parameter optimization design method can obtain the optimal parameter combination under the condition of meeting the structure size and process constraint conditions. The present application can effectively reduce the high-frequency loss of the coil, and improve the wireless power transmission efficiency and power density.

Description

Technical Field

[0001] This invention belongs to the field of magnetically coupled resonant wireless power transfer technology, and particularly relates to multilayer PCB-Litz structure wireless power transfer coils and their design methods. Background Technology

[0002] With the continuous development of power electronics technology, printed circuit boards (PCBs) have gradually become an important means of realizing coupled coils in wireless power transmission systems, especially suitable for drones, mobile terminals, and various smart devices with high requirements for lightweight design. This is mainly due to their advantages such as thin and light structure, mature manufacturing process, and high integration. However, under high-frequency operating conditions, the skin effect and proximity effect can significantly increase the AC resistance of the conductor, thus limiting the performance of PCB coils in wireless power transmission systems. Therefore, suppressing the additional losses caused by high-frequency effects is of great significance for reducing the AC resistance of PCB coils and improving the overall system performance.

[0003] Existing methods for optimizing the AC internal resistance of printed circuit board (PCB) wireless power transfer coils mainly include structural parameter optimization, equal-splitting inductor design, and self-resonance. Structural parameter optimization involves optimizing structural parameters such as line width, line spacing, and the number of strands; however, the parameter design is complex, and the internal resistance optimization effect is not significant. Equal-splitting inductor design ensures consistent strand lengths by regularly rotating the conductors from the top to the bottom layer, solving the inductance reduction problem caused by the different path lengths of inner and outer strands; however, it is only suitable for low-power wireless power transfer systems. Self-resonance achieves autonomous resonance through the interlayer distributed capacitance and coil inductance of the winding itself, reducing the use of additional capacitance; however, the system operating frequency is generally high, which is not conducive to practical applications. In summary, existing research focuses on optimizing PCB coil windings. Summary of the Invention

[0004] This invention provides a multilayer PCB-Litz structure wireless power transmission coil and its design method to solve the defects of existing technologies, such as complex parameter design, insignificant internal resistance optimization effect, and high system operating frequency, thereby reducing high-frequency coil loss and improving wireless power transmission efficiency and power density.

[0005] This invention provides a multilayer PCB-Litz structure wireless power transmission coil for use in a wireless power transmission system. The system includes an inverter unit, two compensation capacitors, two multilayer PCB-Litz structure wireless power transmission coils, and a rectifier.

[0006] The multilayer PCB-Litz structure wireless power transmission coil has its conductive layers electrically connected through cross-layer vias, forming a closed three-dimensional conductive path structure. The conductor path in the top layer extends in a counter-clockwise spiral and gradually shifts outwards radially. When it reaches the outermost boundary, it connects to the second conductive layer through a via, completing a cross-layer transposition. The conductor path in the second conductive layer also extends in a counter-clockwise spiral and gradually shifts inwards radially. When it reaches the innermost boundary, it connects to the third conductive layer through a via. The conductor paths in the third, fourth, and fifth layers are sequentially connected across layers in an alternating inward and outward shift pattern, and the interlayer transposition is achieved through pre-set vias. The conductor path in the bottom layer, after reaching its inner position, reconnects to the top layer through a via, thus forming a multilayered, closed, transposed conductive structure. The via connection points between each conductive layer are distributed according to a pre-set positional rule, and together with the spiral traces, constitute a multilayered, interlaced equivalent Litz conductor structure.

[0007] This invention also provides a method for designing parameters of a wireless power transfer coil in a multilayer PCB-Litz structure, comprising the following steps: S1. Divide the single conductor into groups composed of... n x × n y A matrix composed of infinitesimal elements, where... n x and n y These represent the number of infinitesimal elements that divide the conductor horizontally and vertically, respectively, with each infinitesimal element having a width of Δ. l The infinitesimal elements are numbered in order from left to right and from bottom to top; thus, we obtain... n x n y n tur n lay n str A resistance matrix composed of elements ; S2. According to Grover's formula, find the first... i The and the first j Mutual inductance between infinitesimal circular conductor units; S3. Ignoring the core thickness and assuming the reflection coefficient is constant, the mutual inductance considering the core's influence is obtained using the mirror coil method, thus yielding... n x n y n tur nlay n str An inductor matrix composed of elements ; S4. Construct the discretized impedance matrix ,in ω = 2π f ; S5. Introducing the mapping matrix S ; S6. Construct by n tur n lay n str An impedance matrix composed of concentric circular coils ; S7. For the impedance matrix Z str The inductors and resistors in the diagram are reorganized according to their structure and arranged in node order to obtain the first... i The segmented impedance is: ;in n seg The total number of segments, Y i This is a reordering matrix; S8. Obtain the equivalent impedance matrix by accumulating segment by segment. ; S9. Solve for the coil inductance based on the equivalent impedance obtained in S8. L Litz and internal resistance R Litz .

[0008] According to the present invention, a method for designing parameters of a multilayer PCB-Litz structure wireless power transfer coil is provided. The specific steps of S1 are as follows: No. n The coordinates of the infinitesimal elements are ( r n , z n ),in r n Indicates radius, z n Indicates the distance from the surface of the magnetic core; by n x n y n tur n lay n str A resistance matrix composed of elements R elefor:

[0009] in, σ The electrical conductivity of the conductor material; According to the present invention, a method for designing parameters of a multilayer PCB-Litz structure wireless power transfer coil is provided, wherein the free space in S2 is the first i The and the first j Mutual inductance between infinitesimal circular conductor units for:

[0010]

[0011] Where, Δ z = | z i - z j |, q For elliptic integral parameters, μ 0 represents the free-space permeability; elliptic integrals of the first and second kind K ( q )and E ( q )for:

[0012] in, θ This represents the integration variable in an elliptic integral. According to the design method for wireless power transfer coil parameters of a multilayer PCB-Litz structure provided by the present invention, the mutual inductance considering the influence of the magnetic core in step S3 is as follows:

[0013] in, μ r Indicates the relative permeability of the magnetic core; the first i The inductance of an infinitesimal coil consists of free-space inductance and a correction term:

[0014] in, g The geometric mean radius coefficient, Δ l The width of the infinitesimal element is represented for a square structure. g = 0.44705; by n x n y n tur n layn str An inductor matrix composed of elements L ele for: .

[0015] According to the method for designing parameters of a multilayer PCB-Litz structure wireless power transfer coil provided by the present invention, the mapping matrix in S5 is:

[0016] Where 1 represents 1 × n str n lay identity matrix: .

[0017] According to the present invention, a method for designing parameters of a multilayer PCB-Litz structure wireless power transfer coil is provided, wherein step S8 involves obtaining the equivalent impedance matrix by accumulating segment by segment. Z Litz for:

[0018] in K Kronecker block matrix: .

[0019] According to the present invention, a method for designing parameters of a multilayer PCB-Litz structure wireless power transfer coil is provided, wherein the coil inductance in step S9 is described in step S9. L Litz and internal resistance R Litz for:

[0020] Where Re represents the real part operation and Im represents the imaginary part operation.

[0021] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the wireless power transfer coil parameter design method of any of the above-described multilayer PCB-Litz structure.

[0022] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for designing parameters of a multilayer PCB-Litz structure wireless power transfer coil as described above.

[0023] Compared with the prior art, the present invention has the following beneficial effects: This invention constructs a multilayer PCB-Litz structure wireless power transmission coil and its transposed three-dimensional conductive path, forming a periodically interlaced closed conductive network structure between the conductive layers. This achieves uniform conductor distribution in a spatial magnetic field environment, improves the consistency of current distribution among multilayer conductors, and reduces equivalent AC losses under high-frequency operating conditions. By introducing a transposed via connection structure across layers on the basis of multilayer spiral traces, the conductor path alternates in the radial and interlayer directions, structurally reducing current concentration and improving conductor utilization efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of PCB winding traces provided in an embodiment of the present invention; Figure 2 This is a three-dimensional structural schematic diagram of the multilayer PCB-Litz structure coil provided in an embodiment of the present invention; Figure 3 This is a three-dimensional structural diagram of the via interconnection in a multilayer PCB-Litz structure coil provided in an embodiment of the present invention; Figure 4 This is a top view and a magnified detail view of the multilayer PCB-Litz structure coil provided in the embodiment of the present invention; Figure 5 This is a simplified concentric circle model of the multilayer PCB-Litz structure coil provided in the embodiments of the present invention; Figure 6 This is an equivalent diagram of the segmented structure of the multilayer PCB-Litz coil at different spatial positions provided in the embodiments of the present invention; Figure 7 This is a simplified concentric circle structure diagram in a two-dimensional cylindrical coordinate system provided in an embodiment of the present invention; Figure 8 This is the equivalent circuit diagram of the simplified concentric circle model of the multilayer PCB-Litz structure coil provided in the embodiment of the present invention; Figure 9 This is a flowchart of parameter optimization for the multilayer PCB-Litz coil structure provided in this embodiment of the invention; Figure 10 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] This embodiment presents a multilayer PCB-Litz structure wireless power transmission coil. The coil is constructed from multiple conductive layers of a printed circuit board. It utilizes multilayer planar spiral wiring and interlayer vias to form a three-dimensional conductive path, creating a transposed, staggered Litz structure conductor to improve the uneven current distribution under high-frequency conditions. A multi-conductor transposition via arrangement method is proposed. By setting interlayer vias at equal intervals or according to periodic rules along the conductor path, a one-to-one transposed connection of conductors in the multilayer structure is achieved, thereby improving the uniformity of current distribution.

[0028] Specifically, such as Figure 1 This is a schematic diagram of the PCB winding traces in this embodiment. Figure 2 This is a three-dimensional structural diagram of the multilayer PCB-Litz structure coil in this embodiment. The coil includes a multilayer conductive layer structure, wherein the top conductor extends spirally in a counterclockwise direction and gradually shifts outward in the radial direction. When it reaches the outermost boundary, it connects to the second conductive layer through a via, thereby completing one cross-layer transposition. The conductor path in the second conductive layer extends spirally in a counterclockwise direction and gradually shifts inward in the radial direction. When it reaches the innermost boundary, it connects to the third conductive layer through a via. The conductor paths of the third, fourth, and fifth layers are sequentially connected across layers through vias in an alternating radial inward and outward shift manner. After the bottom conductor reaches the innermost position, it is reconnected to the top layer through a via, thereby forming a multilayer closed-loop transposition conductive structure.

[0029] like Figure 3 As shown, this embodiment is a three-dimensional structural diagram of via interconnection in a multilayer PCB-Litz structure coil. The vias are arranged periodically between different conductive layers according to the conductor transposition rule, so that the conductor paths between adjacent layers form a one-to-one cross-layer connection relationship, thereby forming a three-dimensional interlayer interconnection network structure with periodic alternation characteristics.

[0030] like Figure 4 As shown, this embodiment presents a top view and a partially enlarged detail of the multi-layer PCB-Litz structure coil. The coil exhibits a multi-layer planar spiral distribution structure in the top view, and its geometric parameters include the outer diameter... r out With inner diameter r inThe spiral conductor extends radially from the inside out or from the outside in, and according to a set number of turns. n tur Forming a closed helical path; conductor linewidth l w Line spacing d w and copper thickness l h Used to define the lateral dimensional characteristics and current carrying capacity of a single-layer conductor; the spacing between adjacent turns is determined by... d t Characterized by, the overall pitch of the helix is ​​determined by d st This determines the formation of a regularly distributed planar conductive network structure. The multi-strand conductor structure is further shown in the enlarged partial view. n str The parallel distribution of conductors in a single layer, and the connection relationship between cross-layer vias and adjacent layers, are used to reflect the transposed staggered arrangement of conductors in a multilayer PCB structure.

[0031] like Figure 5 As shown, this embodiment only considers the simplified concentric circle model of the multilayer PCB-Litz structure coil when considering only the coil radius difference. When only considering the coil radius difference, the spiral coil is equivalent to a simplified representation of the concentric circle structure. In this equivalence process, the geometric differences between the spiral structure and the concentric circle, as well as the structural differences introduced by the transpose connection, are ignored, and the outer radius parameter of the concentric circle model is determined according to the equivalence principle.

[0032] like Figure 6 As shown, this embodiment presents an equivalent diagram of the coil in a multilayer PCB-Litz structure, which is composed of segments at different spatial locations. It illustrates the equivalent representation of a conductor in a multilayer PCB-Litz structure consisting of multiple segments located at different spatial locations. Each segment has different impedance characteristics due to its different location. The concentric equivalent segments are connected in series according to the Litz transpose wiring topology to form a segmented equivalent model structure for characterizing the equivalent impedance characteristics of the multilayer Litz conductor.

[0033] like Figure 7 As shown, this embodiment presents a simplified concentric circle structure in a two-dimensional cylindrical coordinate system. Its impedance calculation can be equivalently represented in the two-dimensional cylindrical coordinate system. The outer radius of the coil is... r out Inner radius is r in , and by n tur The structure consists of turns, with a spacing between adjacent turns of [missing information]. d t ; the coil is made of n layComposed of a layered conductive structure, each layer contains n str Parallel conductors; the geometric parameters of the conductor structure include copper thickness. l h Line width l w and conductor spacing d w It is used to characterize the spatial distribution characteristics of multilayer PCB conductors in the radial and axial directions, thus forming an equivalent two-dimensional cylindrical coordinate model for impedance analysis.

[0034] like Figure 8 As shown, the equivalent circuit diagram of the simplified concentric circle model of the multilayer PCB-Litz structure coil in the embodiment is illustrated. To obtain the equivalent impedance of the Litz structure coil, the equation is... The inductance and resistance parameters corresponding to each concentric circle segment are as follows: Figure 5 The structure shown is recombined and rearranged according to the Litz transpose connection relationship. In the analysis, the mutual inductance and mutual resistance between different segments are ignored, and each concentric circle equivalent segment is equivalent to an independent impedance unit and connected in series, thus obtaining an equivalent circuit model for characterizing the overall impedance characteristics of the coil in the multilayer PCB-Litz structure.

[0035] This embodiment also proposes a parameter design method for a multilayer PCB-Litz structure wireless power transmission coil. By using transposed conductor routing and segmented impedance modeling, a balanced current distribution is achieved. Furthermore, high-frequency equivalent impedance analysis is combined to precisely optimize structural parameters, reducing AC losses and improving the performance of the wireless power transmission system. The three-dimensional structure is equivalent to a two-dimensional multi-branch coupled network. Segmented modeling using differential units and impedance mapping and accumulation based on commutation relationships are employed. A via parasitic parameter correction model is introduced to improve the accuracy of high-frequency impedance calculation. In addition, a multi-parameter optimization design method is proposed, aiming to maximize the quality factor or minimize AC losses, to obtain the optimal parameter combination under the constraints of structural dimensions and manufacturing processes. This invention effectively reduces high-frequency coil losses, improves wireless power transmission efficiency and power density, and is suitable for high-frequency, thin and lightweight wireless power transmission systems.

[0036] like Figure 9 The flowchart shown illustrates the parameter optimization process for the multilayer PCB-Litz coil structure in this embodiment. The multivariate optimization solution method, which satisfies PCB manufacturing process constraints, current density constraints, and frequency operating constraints, includes: 1) Determine the initial design parameters of the coil, including the outer diameter, based on the application requirements and structural size limitations of the wireless power transmission system. r out Number of floors n lay substrate thicknessh pcb Magnetic core size l fer and gap height l h ; 2) Based on manufacturing process constraints and geometric relationships, a feasible region for parameters is constructed, and the conductor width is considered. l w Set minimum constraints l w And establish parameter combination relationships that satisfy geometric constraints:

[0037] 3) Select the number of conductor strands within the feasible region. n str With conductor width l w As optimization variables, and construct the objective function Q ( n str , l w The objective function is the coil quality factor; 4) Using the current parameter point ( n str , l w Centered on ) and following the preset step size Δ l w Construct a neighborhood parameter set, and generate a candidate parameter point set by adding or subtracting perturbations from the optimization variables:

[0038] 5) Calculate the objective function value for each parameter point in the neighborhood set. Q ( n str , l w ), and satisfy the coil inductance L Not less than the target inductance L obj Under the constraints, the parameter combination that maximizes the objective function is selected as the new current solution; 6) Repeat steps 4) to 5) until there are no parameter points in the neighborhood that would further increase the objective function, thus obtaining a local optimum.

[0039] 7) Traverse different numbers of turns n turIn the corresponding parameter space, for each number of turns condition, execute steps 1) to 6) and record the corresponding optimal quality factor and its parameter combination; 8) Compare the optimal quality factors corresponding to all turns, select the maximum value as the global optimal solution, and output the corresponding coil structure parameters.

[0040] The method of the present invention can be extended to other situations, not limited to circular windings.

[0041] Figure 10 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 10 As shown, the electronic device may include a processor, a communications interface, a memory, and a communication bus. The processor, communications interface, and memory communicate with each other via the communication bus. The processor can call logic instructions from the memory to execute a multilayer PCB-Litz structure wireless power transfer coil parameter design method.

[0042] Furthermore, the logical instructions in the aforementioned memory can be implemented as software functional units and sold or used as independent products, and can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0043] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the multilayer PCB-Litz structure wireless power transfer coil parameter design method provided by the above methods.

[0044] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0045] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multilayer PCB-Litz structure wireless power transfer coil, characterized in that, The conductive layers of the coil are electrically connected through interlayer vias, forming a closed three-dimensional conductive path structure. The conductor path at the top layer extends in a counterclockwise spiral and gradually shifts outward in the radial direction. When it reaches the outermost boundary, it connects to the second conductive layer through a via, completing an interlayer transposition. The conductor path in the second conductive layer also extends in a counterclockwise spiral and gradually shifts inward in the radial direction. When it reaches the innermost boundary, it connects to the third conductive layer through a via. The conductor paths of the third, fourth, and fifth layers are connected across layers in an alternating inward and outward shift manner, and the interlayer transposition is achieved through preset vias. The conductor path at the bottom layer reconnects to the top layer through a via after reaching the inner position, thus forming a multi-layered, closed, transposed conductive structure. The via connection points between each conductive layer are distributed according to preset position rules and together with the spiral traces, form a multi-layered, interlaced equivalent Litz conductor structure.

2. A method for designing parameters of a multilayer PCB-Litz structure wireless power transfer coil, characterized in that, This method is used for the wireless power transfer coil of the multilayer PCB-Litz structure as described in claim 1; the method includes the following steps: S1. Divide the single conductor into groups composed of... n x × n y A matrix composed of infinitesimal elements n x and n y These represent the number of infinitesimal elements that divide the conductor horizontally and vertically, respectively, with each infinitesimal element having a width of Δ. l The infinitesimal elements are numbered in order from left to right and from bottom to top; S2. According to Grover's formula, find the first... i The and the first j Mutual inductance between infinitesimal circular conductor units; S3. Ignoring the core thickness and assuming the reflection coefficient is constant, the mutual inductance considering the core influence is obtained using the mirror coil method, thus yielding... n x n y n tur n lay n str An inductor matrix composed of elements ; S4. Construct the discretized impedance matrix ,in ω = 2π f ; S5. Introducing the mapping matrix S ; S6. Construct by n tur n lay n str An impedance matrix composed of concentric circular coils ; S7. For the impedance matrix Z str The inductors and resistors in the diagram are reorganized according to their structure and arranged in node order to obtain the first... i The segmented impedance is: ;in n seg The total number of segments, Y i This is a reordering matrix; S8. Obtain the equivalent impedance matrix by accumulating segment by segment. ; S9. Solve for the coil inductance based on the equivalent impedance obtained in S8. L Litz and internal resistance R Litz .

3. The method for designing wireless power transfer coil parameters for a multilayer PCB-Litz structure according to claim 2, characterized in that, The specific steps of S1 are as follows: No. n The coordinates of the infinitesimal elements are ( r n , z n ),in r n Indicates radius, z n Indicates the distance from the surface of the magnetic core; by n x n y n tur n lay n str A resistance matrix composed of elements R ele for: in, σ denoted as , where is the electrical conductivity of the conductor material.

4. The method for designing wireless power transfer coil parameters for a multilayer PCB-Litz structure according to claim 3, characterized in that, In the free space described in S2, the first i The and the first j Mutual inductance between infinitesimal circular conductor units for: Where, Δ z = | z i - z j |, q For elliptic integral parameters, μ 0 represents the free-space permeability; elliptic integrals of the first and second kind K ( q )and E ( q )for: in, θ This represents the integration variable in an elliptic integral.

5. The method for designing wireless power transfer coil parameters for a multilayer PCB-Litz structure according to claim 4, characterized in that, The mutual inductance considering the influence of the magnetic core as described in S3 for: in, μ r Indicates the relative permeability of the magnetic core; the first i The inductance of an infinitesimal coil consists of free-space inductance and a correction term: in, g The geometric mean radius coefficient, Δ l The width of the infinitesimal element is represented for a square structure. g = 0.44705; by n x n y n tur n lay n str An inductor matrix composed of elements L ele for: 。 6. The method for designing wireless power transfer coil parameters for a multilayer PCB-Litz structure according to claim 5, characterized in that, The mapping matrix described in S5 is: Where 1 represents 1 × n str n lay identity matrix: 。 7. The method for designing wireless power transfer coil parameters for a multilayer PCB-Litz structure according to claim 6, characterized in that, The equivalent impedance matrix obtained by stepwise accumulation as described in S8 is: in K Kronecker block matrix: 。 8. The method for designing wireless power transfer coil parameters for a multilayer PCB-Litz structure according to claim 7, characterized in that, S9 coil inductance L Litz and internal resistance R Litz for: Where Re represents the real part operation and Im represents the imaginary part operation.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method as described in any one of claims 1 to 7.

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