A thermal matrix coupling mechanism and a spatial magnetic focusing enhancement design method for WPT systems

Abstract

This invention belongs to the technical field of WPT systems, specifically relating to a thermal matrix coupling mechanism and a spatial magnetic focusing enhancement design method for WPT systems; the thermal matrix coupling mechanism includes a centrally symmetrical transmitting mechanism and a receiving mechanism opposite to the transmitting mechanism; the transmitting mechanism includes three identical transmitting coils, each transmitting coil consisting of n... p The main coils are wound in a single coil, with the centers of all the main coils forming a transmitting coil aligned on a straight line. The centers of the outermost main coils of the three transmitting coils are connected in pairs to form an equilateral triangle. The centers of the remaining main coils in each transmitting coil, excluding the outermost coil, are arranged equidistantly from the outside inwards towards the centroid of the equilateral triangle. The receiving mechanism includes a receiving coil, which is composed of n... s The secondary coils are wound in a single-turn configuration, with all secondary coils having the same center. This invention improves mutual inductance utilization without relying on any auxiliary coils or circuits.

Description

Technical Field

[0001] This invention belongs to the technical field of WPT systems, specifically relating to a thermal matrix coupling mechanism and a spatial magnetic focusing enhancement design method for WPT systems. Background Technology

[0002] Currently, UAVs (Unmanned Aerial Vehicles) / AGVs (Automated Guided Vehicles) play a crucial role in industrial inspection, office logistics, agricultural and forestry plant protection, and military reconnaissance and surveillance. Demonstration applications of multi-level, multi-modal power supply have been designed for smart parks and industrial inspection sites to enable charging docking between different unmanned devices. However, most of these demonstration applications currently employ fixed-point charging, which is cumbersome in its energy transfer process and suffers from significant energy loss. Finding suitable charging pads in challenging environments such as the field or underwater is difficult. Therefore, hovering charging technology for UAVs has become the most crucial charging solution to improve and is key to building wireless power transmission network application environments.

[0003] With the technologies for hovering and following unmanned inspection equipment in air-to-air, ground-to-ground, and air-to-ground applications already well-developed, hovering recharging / alignment recharging is undoubtedly a highly efficient and cutting-edge design approach for unmanned inspection equipment. Currently, to further enhance the flexibility and reliability of wireless charging systems, more and more wireless charging systems are designed based on matrix coils. Matrix multi-excitation wireless charging systems, with their transmitter's magnetic field reconstruction mechanism and stronger tolerance to voltage and current stress, have gained favor in more charging applications. However, due to the large number of coils, current matrix coil designs are based on regular layouts and have not further designed methods to improve transmission distance from the perspectives of unit association and overall energy transfer mechanism. Furthermore, the description and evaluation of spatial power supply capabilities in the context of multi-excitation units are still incomplete. Utilizing the characteristics of multiple coils to enhance the magnetic focusing capability of the energy transmission mechanism is particularly important, and providing a mature method for evaluating transmission capabilities is also the goal of this patent. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a thermal matrix coupling mechanism and a spatial magnetic focusing enhancement design method for WPT systems.

[0005] In a first aspect, the present invention provides a thermal matrix coupling mechanism, comprising a centrally symmetrical transmitting mechanism and a receiving mechanism opposite to the transmitting mechanism;

[0006] The transmitting mechanism includes three identical transmitting coils, each of which consists of n... pThe main coil is constructed by winding 1 turn of the main coil, and the centers of all the main coils that make up a transmitting coil are distributed on a straight line; the centers of the outermost main coils of the three transmitting coils are connected in pairs to form an equilateral triangle; the centers of the remaining main coils in each transmitting coil, except for the outermost main coil, are arranged inward at equal intervals from the outside to the center of gravity of the equilateral triangle.

[0007] The receiving mechanism includes a receiving coil, the receiving coil being composed of n s It is constructed by winding a secondary coil with 1 turn, and all secondary coils have the same center.

[0008] In a second aspect, based on the mechanism of the first aspect, the present invention provides a spatial magnetic focusing enhancement design method for a WPT system, comprising the following steps:

[0009] S1. Determine the initial parameters of the WPT system based on the target application scenario. The initial parameters include the operating frequency f and the radius R of the outermost main coil of the transmitting coil. pnp The radius R of the outermost secondary coil of the receiving coil sns Target mutual inductance value M target ;

[0010] S2. Set the basic parameters of the thermal matrix coupling mechanism, including the number of turns n of the main coil of the transmitting coil. p The number of turns n of the secondary coil of the receiving coil s The radius R of each turn of the main coil pb The distance d between the centers of every two adjacent main coils in the transmitting coil pt The distance d between the outermost main coils of every two transmitting coils r The radius of each turn of the secondary coil, and the diameter d of the main coil's own wire. wire The distance d between the centers of every two adjacent main coils in the transmitting coil st ;

[0011] S3. Calculate the effective charging area in space according to the calculation method of effective charging area in space, and optimize the spatial magnetic focusing of WPT system.

[0012] The beneficial effects of this invention are:

[0013] This invention introduces a non-centrosymmetric unit matrix coil. This method enhances magnetic focusing performance solely through a two-dimensional planar structure without significantly weakening its anti-offset capability, and requires no additional auxiliary coils or circuits. Furthermore, compared to traditional design methods, this design method produces a lower self-inductance value for the transmitting coil of the same size and number of turns, resulting in higher mutual inductance utilization. This method considers winding costs and maintains offset tolerance while improving mutual inductance utilization without relying on any auxiliary coils or circuits. In addition, a spatial effective charging region calculation method based on the coupling thermal matrix is ​​proposed to evaluate the spatial output characteristics of the coupling mechanism. Through magnetic field calculations and experimental verification, the results show that this method can increase the induced voltage on the receiving side by 10% to 24.7% at the center position, while reducing the self-inductance value of each excitation unit by 10.9%. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the launching mechanism structure in the thermal matrix coupling mechanism of the present invention;

[0015] Figure 2 This is an equivalent circuit model of the WPT system according to an embodiment of the present invention;

[0016] Figure 3 This is a flowchart of the coil parameter optimization process of the present invention;

[0017] Figure 4 This is a schematic diagram illustrating the magnetic focusing effect of the present invention;

[0018] Figure 5 This is a diagram for evaluating the spatial power transmission capability of the present invention.

[0019] Figure 6 A physical sample diagram of the present invention is provided. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The present invention provides a thermal matrix coupling mechanism, including a centrally symmetrical transmitting mechanism and a receiving mechanism opposite to the transmitting mechanism;

[0022] like Figure 1 As shown, the transmitting mechanism includes three identical transmitting coils, each of which consists of n... pThe main coil is constructed by winding 1 turn of the main coil, and the centers of all the main coils that make up a transmitting coil are distributed on a straight line; the centers of the outermost main coils of the three transmitting coils are connected in pairs to form an equilateral triangle; the centers of the remaining main coils in each transmitting coil, except for the outermost main coil, are arranged inward at equal intervals from the outside to the center of gravity of the equilateral triangle.

[0023] The receiving mechanism includes a receiving coil, the receiving coil being composed of n s It is constructed by winding secondary coils, and all secondary coils have the same center.

[0024] The thermal matrix coupling mechanism proposed in this invention exhibits central symmetry. The inner loop coil of the transmitting coil differs from the traditional uniform winding method. By tightening the inner loop coil, the magnetic field strength in the central part of the system is enhanced.

[0025] In one embodiment, the present invention also provides a spatial magnetic focusing enhancement design method for a WPT system based on a thermal matrix coupling mechanism, wherein the a=1,2,3rd transmitting coils are arranged from the inside out as b=1,2,…,n p The radius and center coordinates of each main coil are R. pb and C Oa_b The design process includes the following steps:

[0026] S1. Determine the initial parameters of the WPT system based on the target application scenario. The initial parameters include the operating frequency f and the radius R of the outermost main coil of the transmitting coil. pnp The radius R of the outermost secondary coil of the receiving coil sns Target mutual inductance value M target .

[0027] S2. Set the basic parameters of the thermal matrix coupling mechanism, including the number of turns n of the main coil of the transmitting coil. p The number of turns n of the secondary coil of the receiving coil s The radius R of each turn of the main coil pb The distance d between the centers of every two adjacent main coils in the transmitting coil pt The distance d between the outermost main coils of every two transmitting coils r The radius of each turn of the secondary coil, and the diameter d of the main coil's own wire. wire The distance d between the centers of every two adjacent main coils in the transmitting coil st .

[0028] Specifically, such as Figure 3 As shown, step S2 specifically includes:

[0029] S21. Based on the principle of the equivalent center circle of the coil, determine the radius R of the innermost main coil of the transmitting coil. p1And the radius R of the innermost secondary coil of the receiving coil. s1 Based on the cross-coupling effects of mutual modeling, the cross-coupling inductance M of the transmitting mechanism is determined. t_cross ;

[0030] Specifically, the comfort zone of system transmission energy is evaluated by the ratio of transmission distance to coupling mechanism size. For a kHz WPT system, a pitch-to-diameter ratio below 0.7 represents the coupling comfort zone, while the transmission capacity of the WPT system reaches its limit when the pitch-to-diameter ratio reaches 1. Generally, system performance is optimal when the transmission distance is less than or equal to the minimum coil size of the transmitting and receiving coils. This is used to determine the radius R of the innermost main coil of the transmitting coil. p1 The radius R of the innermost secondary coil of the receiving coil s1 .

[0031] S22. Arrange the outermost main coils of the three transmitting coils according to the principle of equilateral polygons; establish a Cartesian coordinate system, determine the center coordinates of the outermost main coil of each transmitting coil, and ensure that the coordinates of these three center coils satisfy symmetry;

[0032] S23. Set d pt =0,d r =0, initialize the number of iterations of the main loop i = 1;

[0033] S24. Set n p =1, n s =1, initialize the number of iterations j = 1;

[0034] S25. Calculate the cross-inductance between every two transmitting coils, and calculate the total mutual inductance M of the three transmitting coils. sum =M 12 +M 13 +M 23 ; where M 12 M 13 M 23 These represent the cross-inductance between the first and second transmitting coils, between the first and third transmitting coils, and between the second and third transmitting coils, respectively.

[0035] S26. Determine if 0.95M is satisfied. target ≤M sum ≤1.05M target If so, record the current indicator status A. ij , let d pt =d pt +△d pt , △d pt This represents the distance increase factor within the main coil, j = j + 1, then proceed to step S28; otherwise, let n... s =ns +1, then proceed to step S27; the indicator details include d pt d r n p and n s The current values ​​of these four parameters;

[0036] S27. Determine if the condition is satisfied. If yes, proceed to step S25; otherwise, proceed to step S28.

[0037] S28. Let n p =n p +1, n s =1; Determine if the condition is met. If yes, proceed to step S25; otherwise, proceed to step S29.

[0038] S29. Select the optimal index situation in the current i-th major loop, and determine whether the optimal index situation satisfies 0.95M. t_cross ≤M sum ≤1.05M t_cross If so, then set the parameters of the heat matrix coupling mechanism according to the optimal index condition; otherwise, let i = i + 1, d p =0,d r =d r +△d r Execute step S24; where △d r This represents the distance increase factor outside the main coil.

[0039] S3. Determine the charging mode and charging direction based on the charging demand response, and set the compensation parameters for the thermal matrix coupling mechanism. This invention mainly evaluates the spatial output characteristics of the thermal matrix coupling mechanism based on the spatial effective charging area calculation method.

[0040] Specifically, step S3 includes:

[0041] S31. Construct an equivalent circuit model of the WPT system, setting the three transmitting coils as L... p1 L p2 L p3 The receiving coil is L s The internal resistances of the three transmitting coils are R0 and R1 respectively. p1 R p2 R p3 The internal resistance of the receiving coil is R. Ls The capacitances at the three transmitting coils are C0 and C1 respectively. p1 C p2 C p3 The compensation inductors are L r1 L r2 L r3The internal resistances of the compensating inductors are R and R, respectively. Lr1 R Lr2 R Lr3 The series compensation capacitor, parallel compensation capacitor, and compensation inductor at the receiving coil are C, respectively. s C sr L sr Four switches S1-S4 are installed on the transmitting coil side, and a filter capacitor C is installed on the receiving coil side. r Load R L ; where C p1 =C p2 =C p3 L p1 =L p2 =L p3 ,

[0042] R p1 =R p2 =R p3 i p1 i p2 i p3 i1, i2, and i3 represent the currents flowing through the 1st, 2nd, and 3rd transmitting coils, respectively; i1, i2, and i3 represent the currents flowing through the 1st, 2nd, and 3rd compensating inductors, respectively. s i represents the current flowing through the receiving coil. sr This represents the input current of the rectifier bridge. in The square wave voltage output by the inverter, u s C is the input voltage of the rectifier circuit. r For the filter capacitor, R o For load;

[0043] S32. Construct a magnetic field coupling space model based on the basic parameters of the thermal matrix coupling mechanism set in step S2, and calculate the mutual inductance at any coordinate point in space;

[0044] S33. Construct a power distribution surface function to calculate the output power and set the target rated power;

[0045] S34. Based on the given coil dimensions, define three n-dimensional vectors x, y, and z, as well as the spatial grid size σ; combine the magnetic field coupling spatial model to calculate the spatial mutual inductance matrix of each transmitting coil;

[0046] S35. Calculate the power matrix of the transmitting mechanism based on the spatial mutual inductance matrix and the power distribution surface function; calculate the volume of the effective spatial charging region based on the power matrix.

[0047] In one embodiment, the transmitting mechanism in the thermal matrix coupling mechanism proposed in this invention is as follows: Figure 1As shown, a three-transmitter coil architecture is employed, and the entire coupling mechanism exhibits central symmetry. The inner loop coil differs from traditional uniform winding methods; by tightening the inner loop coil, the magnetic field strength in the central part of the system is enhanced. The main coil parameters in the multiple transmitter coils are identical. Figure 1 Based on this, a Cartesian coordinate system is established. For the outermost main coil of three transmitting coils with defined dimensions, the coordinates of its center point can be expressed as:

[0048]

[0049]

[0050] The main coils in the transmitting coil, except for the outermost main coil, are spaced at a distance d. pt Arranged in an equidistant, inwardly recessed configuration, the center coordinates of the b-th turn of the main coil in each transmitting coil can be expressed as:

[0051]

[0052] Among them, C O1_b (x 1_b ,y 1_b () represents the coordinates of the center of the b-th turn of the main coil in the first transmitting coil, C O2_b (x 2_b ,y 2_b () represents the center coordinates of the b-th turn of the main coil in the second transmitting coil, C O3_b (x 3_b ,y 3_b () represents the coordinates of the center of the b-th turn of the main coil in the third transmitting coil. Meanwhile, from Figure 1 It can be seen that the coordinates of the center C of the innermost main coil, i.e., the central circular coil, within the transmitting coil are... oi_1 There are limits to the winding process when maintaining equidistant inward spacing. The radius of the main coil at the outermost edge of the transmitting coil is... In the case where the radius of the b-th turn of the main coil is:

[0053]

[0054] To ensure that the central circular coil satisfies the requirement of equal length d pt With sufficient space to wind the coil into a circle when the coil is concave, the dimensions of the outermost main coil must meet the following conditions:

[0055]

[0056] Therefore, the trajectory equation of the b-th turn of the main coil in the first transmitting coil is Coil 1_b (b = 1, 2, ..., n) p ):

[0057]

[0058] The trajectory equation of the b-th turn of the main coil in the second transmitting coil (Coil) 2_b (b = 1, 2, ..., n) p ):

[0059]

[0060] The trajectory equation of the b-th turn of the main coil in the third transmitting coil (Coil) 3_b (b = 1, 2, ..., n) p ):

[0061]

[0062] Where x and y are the variables in the equation.

[0063] Taking the first transmitting coil as an example, according to the Newman formula, the mutual inductance between two different current-carrying conductors can be expressed as:

[0064]

[0065] Among them, M bc C represents the mutual inductance between the b-th turn of the main coil in the transmitting coil and the c-th turn of the secondary coil in the receiving coil. b This represents the b-th turn of the main coil in the transmitting coil, l b Let C represent the trajectory equation of the b-th turn of the main coil. c This represents the c-th turn of the secondary coil in the receiving coil, l c Let μc represent the trajectory equation of the c-th turn of the secondary coil, and μ0 represent the permeability. The first transmitting coil is located in the XOY plane, and the receiving coil is assumed to be at a height z above the XOY plane. s R bc Indicate l b With l c The distance between them is calculated using the formula:

[0066]

[0067] The above is the content of step S32, which calculates the mutual inductance at any coordinate point in space based on the magnetic field coupling space model.

[0068] The equivalent circuit model of the WPT system of this invention is constructed as follows: Figure 2 The LCL-LCC topology is shown. To balance the magnetic field distribution, each transmitting coil has the same parameters in the multi-excitation coil matrix. Assuming that the transmitting coil side and the receiving coil side operate at the same angular frequency ω, the relationship between current and voltage can be derived according to Kirchhoff's Voltage Law (KVL) as follows (10).

[0069]

[0070] Among them, u in i is the square wave voltage output by the inverter. p1 i p2 i p3 i1, i2, and i3 represent the currents flowing through the 1st, 2nd, and 3rd transmitting coils, respectively; i1, i2, and i3 represent the currents flowing through the 1st, 2nd, and 3rd compensating inductors, respectively. s U represents the current flowing through the receiving coil. p1 u p2 u p3 These represent the voltages at the 1st, 2nd, and 3rd transmitting coils, respectively.

[0071] Let R o =8R L / π 2 , where R o for Figure 2 The equivalent impedance of the subsequent stage circuit after the second red dashed line in the diagram can also be called the load; the equivalent impedance Z on the receiving coil side. s =L sr / C sr (8R L / π 2 +R Lsr ), angular frequency ω is defined as

[0072]

[0073] Since the parasitic resistance of the compensating inductor is small, R is negligible. Lr1 R Lr2 and R Lr3 By simplifying equation (10), the input current equation can be obtained as follows:

[0074]

[0075] L p =L p1 =L p2 =L p3 L will be used in the following text. p This refers to the inductance of any transmitting coil; the LCL composite resonant network has good robustness and excellent constant current characteristics to dynamic load changes. Therefore, from the perspective of the overall system output power, the magnitude of the cross inductance has almost no impact on it. Thus, the secondary resonant current i... s It can be represented as

[0076]

[0077] Among them, C p =C p1 =C p2=C p3 The following text uses C. p M refers to the capacitance at any transmitting coil; a R represents the mutual inductance between the a-th transmitting coil and the receiving coil. Ls This is expressed as the internal resistance of the secondary coil.

[0078] It can be observed that under good parameter matching, the induced voltage on the receiving coil side increases with the increase of the excitation unit. For equations (12) and (13), the resonant current is equal when the input voltage of the excitation unit is consistent. Under the condition of ensuring in-phase excitation current, the expression for the system power can be obtained as follows:

[0079]

[0080] According to the mutual inductance equation (8) and Figure 1 Mutual inductance M can be inferred a This is related to the variable spatial location (a = 1, 2, 3). Let the overall center coordinates of the a-th transmitting coil be (x... a ,y a The coordinates of the center of the secondary coil (receiving coil) are (x, 0), and the coordinates of the center of the secondary coil (receiving coil) are (x, 0). s ,y s ,z s ),by Figure 1 For example, the overall center coordinates of the three transmitting coils are C O1_1 C O2_2 C O3_3 The power distribution surface function P(x) at any location can be obtained by using the induced voltage equation (13). s ,y s ,z s )

[0081]

[0082] L p M represents the inductance of the transmitting coil, ω represents the angular frequency, and M represents the angular frequency. as This indicates that the coordinates of the a-th transmitting coil relative to the overall center are (x, y). s ,y s ,z s The mutual inductance between the receiving coils of ) can be expressed by the power distribution surface function P(x) mentioned above. s ,y s ,z s Calculate the output power. For a matrix coil, when the coil currents are in phase, the secondary coil obtains the maximum energy and converts P... target Set the target output power for the load. At the specified transmission height z... s Next, construct a z-axis value of P. target (i.e., z = P)target The plane of ) can be represented as:

[0083]

[0084] i p This represents the current flowing through the transmitting coil.

[0085] The global center coordinates of the receiving coil at any position in space are (x s ,y s ,z s Given the coil dimensions, define three n-dimensional vectors x, y, and z, and a spatial grid size σ, where σ represents the unit increment of Δx, Δy, and Δz.

[0086]

[0087] in,

[0088]

[0089] x i Let y represent the i-th element of vector x. i Let z represent the i-th element of vector y. i Let represent the i-th element of vector z. It can be seen that σ*(n-1) is actually the distance the coil moves along a certain axis.

[0090] by Figure 1 For example, similarly, for the proposed transmitting mechanism, based on the previous analysis, the center coordinates of each turn of the main coil of the transmitting coil are variable. Starting from equation (2), let C... Oa_b (x a_b ,y a_b (b, 0) represents the center coordinates of the b-th turn of the main coil in the a-th transmitting coil (b = 1, 2, ..., n). p (a = 1, 2, 3). For the b-th turn of the main coil in the a-transmitting coils, its lateral offset matrix Φ relative to the receiving coil is... a_b It can be represented as:

[0091]

[0092] e represents a unit vector. Therefore, it can be deduced that at a fixed transmission distance z... s Below, the spatial mutual inductance matrix M of the a-th transmitting coil in the proposed transmitting mechanism is... * n×n_a (ρ=1) can be expressed as

[0093]

[0094] in, Let g represent the mutual inductance calculation function in the magnetic field coupling space model, i.e., formula (8). The power distribution surface function of formula (15) is set as a power mapping function based on the mutual inductance value; for ease of writing, it is represented as g. () Therefore, the power matrix P of the proposed launch mechanism can be obtained. * n×n Represented as

[0095]

[0096] In fact, the power matrix P * n×n Describes the transmission distance z i Power distribution surface at such location, such as Figure 5 As shown. According to formula (21), it can be determined whether the system's power transmission capability reaches the target rated power. For a given z... i (z i ∈z), define the function H() to calculate power greater than the rated power P. target Number of grid cells

[0097]

[0098] Among them, P ij Represents the power matrix P * n×n The power point in the i-th row and j-th column of the matrix is ​​calculated using the above formula in the power matrix P. * n×n All power points P ij Greater than the target rated power P target The set of points.

[0099] Calculate at a transmission distance of z i The formula for the effective spatial charging region volume V can be expressed as:

[0100]

[0101] Where z represents the set of transmission distances; n represents the number of dimensions, which is the n scales of the z-axis.

[0102] Finally, the system was optimized and improved based on the volume of the effective charging area. The magnetic focusing effect is shown in Figure 4. An example of a coil with magnetic focusing coupling capability was constructed through optimized design, as shown in Figure 4. Figure 6 As shown.

[0103] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "rotation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0104] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A thermal matrix coupling mechanism, characterized in that, It includes a centrally symmetrical transmitting mechanism and a receiving mechanism opposite to the transmitting mechanism; The transmitting mechanism includes three identical transmitting coils, each of which consists of n... p The main coil is constructed by winding 1 turn of the main coil, and the centers of all the main coils that make up a transmitting coil are distributed on a straight line; the centers of the outermost main coils of the three transmitting coils are connected in pairs to form an equilateral triangle; the centers of the remaining main coils in each transmitting coil, except for the outermost main coil, are arranged inward at equal intervals from the outside to the center of gravity of the equilateral triangle. The receiving mechanism includes a receiving coil, the receiving coil being composed of n s It is constructed by winding secondary coils, and all secondary coils have the same center.

2. A spatial magnetic focusing enhancement design method for a WPT system based on the thermal matrix coupling mechanism described in claim 1, characterized in that, Let the a-th (1, 2, 3) transmitting coils be arranged from the inside out as b-th (1, 2, ..., n). p The radius and center coordinates of each main coil are R. pb and C Oa_b The design process includes the following steps: S1. Determine the initial parameters of the WPT system based on the target application scenario. The initial parameters include the operating frequency f and the radius of the outermost main coil of the transmitting coil. The radius of the outermost secondary coil of the receiving coil Target mutual inductance value M target ; S2. Set the basic parameters of the thermal matrix coupling mechanism, including the number of turns n of the main coil of the transmitting coil. p The number of turns n of the secondary coil of the receiving coil s The radius R of each turn of the main coil pb The distance d between the centers of every two adjacent main coils in the transmitting coil pt The distance d between the outermost main coils of every two transmitting coils r The radius of each turn of the secondary coil, and the diameter d of the main coil's own wire. wire The distance d between the centers of every two adjacent main coils in the transmitting coil st ; S3. Calculate the effective charging area in space according to the calculation method of effective charging area in space, and optimize the spatial magnetic focusing of WPT system.

3. The spatial magnetic focusing enhancement design method for a WPT system according to claim 2, characterized in that, The radius of the outermost main coil of the transmitting coil The following conditions must be met:

4. The spatial magnetic focusing enhancement design method for a WPT system according to claim 2, characterized in that, Step S2 specifically includes: S21. Based on the principle of the equivalent center circle of the coil, determine the radius R of the innermost main coil of the transmitting coil. p1 And the radius R of the innermost secondary coil of the receiving coil. s1 Based on the cross-coupling effects of mutual modeling, the cross-coupling inductance M of the transmitting mechanism is determined. t_cross ; S22. Arrange the outermost main coils of the three transmitting coils according to the principle of equilateral polygons; establish a Cartesian coordinate system, determine the center coordinates of the outermost main coil of each transmitting coil, and ensure that the coordinates of these three center coils satisfy symmetry; S23. Set d pt =0,d r =0, initialize the number of iterations of the main loop i = 1; S24. Set n p =1, n s =1, initialize the number of iterations j = 1; S25. Calculate the cross-inductance between every two transmitting coils, and calculate the total mutual inductance M of the three transmitting coils. sum =M 12 +M 13 +M 23 ; where M 12 M 13 M 23 These represent the cross-inductance between the first and second transmitting coils, between the first and third transmitting coils, and between the second and third transmitting coils, respectively. S26. Determine if 0.95M is satisfied. target ≤M sum ≤1.05M target If so, record the current indicator status A. ij , let d pt =d pt +△d pt , △d pt This represents the distance increase factor within the main coil, j = j + 1, then proceed to step S28; otherwise, let n... s =n s +1, then proceed to step S27; the indicator details include d pt d r n p and n s The current values ​​of these four parameters; S27. Determine if the condition is satisfied. If yes, proceed to step S25; otherwise, proceed to step S28. S28. Let n p =n p +1, n s =1; Determine if the condition is met. If yes, proceed to step S25; otherwise, proceed to step S29. S29. Select the optimal index situation in the current i-th major loop, and determine whether the optimal index situation satisfies 0.95M. t_cross ≤M sum ≤1.05M t_cross If so, then set the parameters of the heat matrix coupling mechanism according to the optimal index condition; otherwise, let i = i + 1, d p =0,d r =d r +△d r Execute step S24; where △d r This represents the distance increase factor outside the main coil.

5. The spatial magnetic focusing enhancement design method for a WPT system according to claim 2, characterized in that, Step S3 specifically includes: S31. Construct an equivalent circuit model of the WPT system, setting the three transmitting coils as L... p1 L p2 L p3 The receiving coil is L s The internal resistances of the three transmitting coils are R0 and R1 respectively. p1 R p2 R p3 The internal resistance of the receiving coil is R. Ls The capacitances at the three transmitting coils are C0 and C1 respectively. p1 C p2 C p3 The compensation inductors are L r1 L r2 L r3 The internal resistances of the compensating inductors are R and R, respectively. Lr1 R Lr2 R Lr3 The series compensation capacitor, parallel compensation capacitor, and compensation inductor at the receiving coil are C, respectively. s C sr L sr Four switches S1-S4 are installed on the transmitting coil side, and a filter capacitor C is installed on the receiving coil side. r Load R L ; where C p1 =C p2 =C p3 L p1 =L p2 =L p3 R p1 =R p2 =R p3 i p1 i p2 i p3 i1, i2, and i3 represent the currents flowing through the 1st, 2nd, and 3rd transmitting coils, respectively; i1, i2, and i3 represent the currents flowing through the 1st, 2nd, and 3rd compensating inductors, respectively. s i represents the current flowing through the receiving coil. sr This represents the input current of the rectifier bridge; u in The square wave voltage output by the inverter, u s C is the input voltage of the rectifier circuit. r For the filter capacitor, R o For load; S32. Construct a magnetic field coupling space model based on the basic parameters of the thermal matrix coupling mechanism set in step S2, and calculate the mutual inductance at any coordinate point in space; S33. Construct a power distribution surface function to calculate the output power and set the target rated power; S34. Based on the given coil dimensions, define three n-dimensional vectors x, y, and z, as well as the spatial grid size σ; combine the magnetic field coupling spatial model to calculate the spatial mutual inductance matrix of each transmitting coil; S35. Calculate the power matrix of the transmitting mechanism based on the spatial mutual inductance matrix and the power distribution surface function; calculate the volume of the effective spatial charging region based on the power matrix.

6. The spatial magnetic focusing enhancement design method for a WPT system according to claim 5, characterized in that, Step S32 constructs a magnetic field coupling spatial model based on the basic parameters of the thermal matrix coupling mechanism set in step S2, and calculates the mutual inductance at any coordinate point in space, including: S321. Determine the coordinates of the center point of each turn of the main coil in each transmitting coil, denoted as: Among them, C O1_b (x 1_b ,y 1_b () represents the coordinates of the center of the b-th turn of the main coil in the first transmitting coil, C O2_b (x 2_b ,y 2_b () represents the center coordinates of the b-th turn of the main coil in the second transmitting coil, C O3_b (x 3_b ,y 3_b () represents the coordinates of the center of the b-th turn of the main coil in the third transmitting coil; S322. Determine the trajectory equation of each turn of the main coil in each transmitting coil based on the coordinates of the center, including: The trajectory equation of the b-th turn of the main coil in the first transmitting coil (Coil) 1_b b = 1, 2, ..., n p : The trajectory equation of the b-th turn of the main coil in the second transmitting coil (Coil) 2_b b = 1, 2, ..., n p : The trajectory equation of the b-th turn of the main coil in the third transmitting coil (Coil) 3_b b = 1, 2, ..., n p : Where x and y are the variables in the equation; S323. Based on the trajectory equation, the mutual inductance between two different current-carrying conductors is calculated using the Newman formula, expressed as: Among them, M bc C represents the mutual inductance between the b-th turn of the primary coil in a transmitting coil and the c-th turn of the secondary coil in a receiving coil. b This represents the b-th turn of the main coil in the transmitting coil, l b Let C represent the trajectory equation of the b-th turn of the main coil. c This represents the c-th turn of the secondary coil in the receiving coil, l c Represent the trajectory equation of the c-th turn of the secondary coil; R bc Indicate l b With l c The distance between them, μ0 represents the permeability.

7. The spatial magnetic focusing enhancement design method for a WPT system according to claim 5, characterized in that, In step S33, the power distribution surface function P(x) is used. s ,y s ,z s Calculate the output power, power distribution surface function P(x) s ,y s ,z s ) represents (x a ,y a (x, 0) represents the global center coordinates of the a-th transmitting coil, (x, 0) s ,y s ,z s L represents the overall center coordinates of the receiving coil. p M represents the inductance of the transmitting coil, ω represents the angular frequency, and M represents the angular frequency. as This indicates that the coordinates of the a-th transmitting coil relative to the overall center are (x, y). s ,y s ,z s The mutual inductance between the receiving coils.

8. The spatial magnetic focusing enhancement design method for a WPT system according to claim 5, characterized in that, Step S34 specifically includes: Define three n-dimensional vectors x, y, and z as x=[x1 x2 … x n ],y=[y1 y2 ... y n ],z=[z1 z2 ... z n ] in, x i Let y represent the i-th element of vector x. i Let z represent the i-th element of vector y. i This represents the i-th element of vector z; For the b-th turn of the main coil in a transmitting coil, its lateral offset matrix Φ relative to the receiving coil is... a_b Represented as: Among them, (x a_b ,y a_b ,z a_b ) represents the center coordinates of the b-th turn of the main coil in the a-th transmitting coil, and e represents the unit vector; The spatial mutual inductance matrix M of the a-th transmitting coil in the transmitting mechanism * n×n_a Represented as in, This represents the mutual inductance calculation function in the magnetic field coupling space model.

9. The spatial magnetic focusing enhancement design method for a WPT system according to claim 5, characterized in that, The power matrix is ​​represented as Among them, P * n×n This represents the power matrix, where 'a' represents the number of the transmitting coil, and M represents the power matrix. * n×n_a Let g() denote the spatial mutual inductance matrix, g() denote the power distribution surface function, and z() denote the mutual inductance matrix. i Indicates the i-th transmission distance; The formula for calculating the volume V of the effective space charging region is: Among them, P target The target rated power is represented by H(), which is a function used to calculate the number of grid cells whose power on the power distribution surface is greater than the target rated power threshold. z represents the transmission distance set, n represents the dimension number, and σ represents the spatial grid size.

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