Heat matrix coupling mechanism and WPT system space magnetic focusing enhancement design method

Abstract

The invention belongs to the technical field of WPT systems, and particularly relates to a heat matrix coupling mechanism and a WPT system space magnetic focusing enhancement design method. The heat matrix coupling mechanism comprises a centrosymmetric transmitting mechanism and a receiving mechanism opposite to the transmitting mechanism; the transmitting mechanism comprises three identical transmitting coils, each transmitting coil is formed by winding np turns of main coils, and the circle centers of all the main coils forming one transmitting coil are distributed on the same straight line; the circle centers of the outermost main coils of the three transmitting coils are connected in pairs to form a regular triangle; the circle centers of the other main coils except the main coil on the outermost side in each transmitting coil are arranged in a manner of retracting inwards at equal intervals from outside to inside in sequence towards the center-of-gravity direction of the regular triangle; the receiving mechanism comprises a receiving coil, the receiving coil is formed by winding ns turns of secondary coils, and the circle centers of all the secondary coils are the same; the method does not depend on any auxiliary coil or circuit, so that the mutual inductance utilization rate is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of WPT systems, and particularly relates to a heat matrix coupling mechanism and a method for enhancing the spatial magnetic focusing of a WPT system. Background Art

[0002] Currently, mobile robots UAV (Unmanned Aerial Vehicle) / AGV (Automated Guided Vehicle) play an important role in industrial inspection, office logistics, agricultural and forestry plant protection, military reconnaissance and surveillance, and other fields. At present, a demonstration application of multi-level and multi-modal power supply has been designed in places such as smart parks and industrial inspections to achieve charging docking between different unmanned devices. However, most of the current power supply methods for this kind of demonstration application adopt fixed-point charging. This multi-level power supply method has a relatively cumbersome energy transfer link and will face more energy loss problems. It is difficult to find suitable conditions for a parking charging pad in special charging environments such as the wild and underwater. Therefore, the hovering charging technology of UAV has become the most urgent charging solution to be improved and is also the key to constructing the application environment of a wireless power transmission network.

[0003] Based on the fact that the technologies of fixed-point hovering and hovering following of unmanned inspection devices in air-to-air, ground-to-ground, and air-to-ground are already very perfect, hovering energy replenishment / aligned energy replenishment is undoubtedly a very efficient and cutting-edge design concept applied to unmanned inspection devices. Nowadays, in order to further improve the flexibility and reliability of wireless charging systems, more and more wireless charging systems are designed based on matrix coils. The matrix multi-excitation wireless charging system has obtained more favor from charging application products due to its characteristics such as the magnetic field reconstruction mechanism at the transmitting end and stronger tolerance to voltage and current stress. However, due to the large number of coils, the current matrix coil designs are all based on regular layout arrangements, and no method for further designing and improving the transmission distance has been developed from the perspective of unit association and overall energy transfer mechanism. In addition, the description and evaluation of the spatial power supply ability in the context of multi-excitation units are not yet perfect. It is particularly important to utilize the characteristics of multi-coils to enhance the magnetic focusing ability of the energy emission mechanism, and at the same time, providing a mature method for evaluating the transmission ability is also the implementation goal of this patent. Summary of the Invention

[0004] To solve the above problems, the present invention provides a heat matrix coupling mechanism and a method for enhancing the spatial magnetic focusing of a WPT system.

[0005] In a first aspect, a heat matrix coupling mechanism provided by the present invention includes a transmitting mechanism that is centrosymmetric, and a receiving mechanism opposite to the transmitting mechanism;

[0006] The transmitting mechanism includes three identical transmitting coils, and each transmitting coil is composed of n p> It is formed by winding the main coil with more than 1 turn, 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 pairwise to form an equilateral triangle; the centers of the remaining main coils in each transmitting coil except the outermost main coil are arranged inwards at equal distances towards the centroid of the equilateral triangle in sequence;

[0007] The receiving mechanism includes a receiving coil, and the receiving coil is formed by winding the secondary coil with n s > turns, and the centers of all the secondary coils are the same.

[0008] In the second aspect, based on the mechanism of the first aspect, a method for enhancing the spatial magnetic focusing of a WPT system provided by the present invention includes the following steps:

[0009] S1. Determine the initial parameters of the WPT system according to the target application scenario, and the initial parameters include the operating frequency f, 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 , the target mutual inductance value M target ;

[0010] S2. Set the basic parameters of the heat 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, the diameter d of the wire of the main coil itself wire , the distance d between the centers of every two adjacent main coils in the transmitting coil st ;

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

[0012] The beneficial effects of the present invention:

[0013] The present invention will introduce a non-centrosymmetric unit matrix coil. This method enhances the magnetic focusing performance relying only on a two-dimensional planar structure with almost no weakening of its anti-offset ability, and without the need for additional auxiliary coils or circuits. In addition, compared with the traditional design method, the self-inductance value of the transmitting coil in this design method is smaller and its mutual inductance utilization rate is higher under the same size and number of turns. While considering the winding cost and maintaining the offset tolerance, this method does not rely on any auxiliary coils or circuits, thus improving the mutual inductance utilization rate. In addition, a method for calculating the spatially effective charging area is proposed based on the coupled thermal matrix to evaluate the spatial output characteristic indexes of the coupling mechanism. Through magnetic field calculation 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 central position, while the self-inductance value of each excitation unit is reduced by 10.9%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the structure of the transmitting mechanism in the heat matrix coupling mechanism of the present invention;

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

[0016] Figure 3 Flow chart of coil parameter optimization according to the present invention;

[0017] Figure 4 Schematic diagram of the magnetic focusing effect according to the present invention;

[0018] Figure 5 Evaluation diagram of the spatial power transmission ability according to the present invention;

[0019] Figure 6 Physical sample diagram of the design according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

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

[0022] As shown in Figure 1 , the transmitting mechanism includes three identical transmitting coils, and each transmitting coil is composed of n pIt is formed by winding more than 1 turn of the main coil, and the centers of all the main coils forming a transmitting coil are distributed on a straight line; the centers of the outermost main coils of the three transmitting coils are connected pairwise to form an equilateral triangle; the centers of the remaining main coils in each transmitting coil except the outermost main coil are arranged inwards at equal distances towards the centroid of the equilateral triangle in sequence from the outside to the inside.

[0023] The receiving mechanism includes a receiving coil, and the receiving coil is formed by winding n s turns of secondary coils, and the centers of all the secondary coils are the same.

[0024] The heat matrix coupling mechanism proposed by the present invention exhibits the characteristic of central symmetry. Among them, the inner ring coil of the transmitting coil is different from the traditional uniform winding method. The present invention enhances the magnetic field intensity in the central part of the system by tightening the inner ring coil.

[0025] In one embodiment, the present invention also provides a method for enhancing the spatial magnetic focusing design of a WPT system based on a heat matrix coupling mechanism. Let the radius and center coordinates of the b = 1, 2,..., n p th main coil of the a = 1, 2, 3 transmitting coils from the inside to the outside be R pb and C Oa_b respectively; the design process includes the following steps:

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

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

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

[0029] S21. According to the principle of the equivalent center circle of the coil, determine the radius R p1, and the radius R of the innermost secondary coil of the receiving coil s1 ; Based on the cross-coupling effect of mutual modeling, determine the cross-coupling inductance M of the transmitting mechanism t_cross ;

[0030] Specifically, the comfort zone of the system's transmitted energy is evaluated by the ratio of the transmission distance to the size of the coupling mechanism. For the kHz WPT system, when the ratio of the diameter to the distance is below 0.7, it is the coupling comfort zone. When the ratio of the diameter to the distance reaches 1, the transmission capacity of the WPT system reaches its limit. Usually, when the transmission distance is less than or equal to the minimum coil size of the transmitting coil and the receiving coil, the system performance is better. Based on this, determine the radius R of the innermost primary coil of the transmitting coil p1 and the radius R of the innermost secondary coil of the receiving coil s1 .

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

[0032] S23. Set d pt =0, d r =0, initialize the number of large loops i = 1;

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

[0034] S25. Calculate the cross mutual 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 respectively represent the cross mutual inductance between the 1st transmitting coil and the 2nd transmitting coil, between the 1st transmitting coil and the 3rd transmitting coil, and between the 2nd transmitting coil and the 3rd transmitting coil;

[0035] S26. Judge whether it satisfies 0.95M target ≤M sum ≤1.05M target , if so, record the current index situation A ij , let d pt =d pt +△d pt , △d pt represents the distance increase factor inside the primary coil, j = j + 1, and then execute step S28; if not, let n s =ns Increment by 1, and then execute step S27; the index conditions include d pt , d r , n p and n s The current values of these 4 parameters;

[0036] S27. Determine whether the following is satisfied If so, execute step S25; if not, execute step S28;

[0037] S28. Let n p = n p + 1, n s = 1; determine whether the following is satisfied If so, execute step S25; if not, execute step S29;

[0038] S29. Select the optimal index condition in the current i-th large loop, and determine whether 0.95M t_cross ≤ M sum ≤ 1.05M t_cross is satisfied under this optimal index condition. If so, set the heat matrix coupling mechanism parameters with this optimal index condition; if not, let i = i + 1, d p = 0, d r = d r + △d r , and execute step S24; where △d r represents the main coil outer distance increase factor.

[0039] S3. Determine the charging mode and charging direction according to the charging demand response, and set the heat matrix coupling mechanism compensation parameters. The present invention mainly evaluates the spatial output characteristic index of the heat matrix coupling mechanism according to the spatial effective charging area calculation method.

[0040] Specifically, step S3 includes:

[0041] S31. Construct an equivalent circuit model of the WPT system, and set the three transmitting coils as L p1 , L p2 , L p3 , and the receiving coil as L s ; the internal resistances of the three transmitting coils are R p1 , R p2 , R p3 , and the internal resistance of the receiving coil is R Ls ; the capacitances at the three transmitting coils are C p1 , C p2 , C p3 , and the compensation inductances are L r1 , L r2 , L r3, the internal resistances of the compensation inductors are R Lr1 、R Lr2 、R Lr3 ; the series compensation capacitor, parallel compensation capacitor, and compensation inductor at the receiving coil are C s 、C sr 、L sr ; four switches S 1 -S 4 are set on the transmitting coil side, a filtering capacitor C r is set on the receiving coil side, and a 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 respectively represent the currents flowing through the 1st, 2nd, and 3rd transmitting coils; i 1 , i 2 , i 3 respectively represent the currents flowing through the 1st, 2nd, and 3rd compensation inductors, i s represents the current flowing through the receiving coil, and i sr represents the input current of the rectifier bridge. u in is the square wave voltage output by the inverter, u s is the input voltage of the rectifier circuit, C r is the filtering capacitor, and R o is the load;

[0043] S32. Construct a magnetic field coupling space model based on the basic parameters of the heat 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. According to the given coil dimensions, define three n-dimensional vectors x, y, and z, and the spatial grid size σ; combined with the magnetic field coupling space model, calculate the spatial mutual inductance matrix of each transmitting coil;

[0046] S35. Based on the spatial mutual inductance matrix, combined with the power distribution surface function, calculate the power matrix of the transmitting mechanism; calculate the volume of the effective space charging area according to the power matrix.

[0047] In one embodiment, the transmitting mechanism in the heat matrix coupling mechanism proposed by the present invention is as follows Figure 1 As shown, a three-transmitting coil architecture is adopted, and the entire coupling mechanism exhibits central symmetry characteristics. The inner-ring coil is different from the traditional uniform winding method; by tightening the inner-ring coil, the magnetic field intensity in the central part of the system is enhanced. The parameters of the main coils in multiple transmitting coils are the same. On the basis of Figure 1 A Cartesian coordinate system is established. For the outermost main coils of the three transmitting coils with determined dimensions, the center point coordinates can be expressed as

[0048]

[0049]

[0050] The remaining main coils in the transmitting coil except the outermost main coil are arranged in an equidistant inward contraction with a distance d pt . Therefore, the center coordinates of the b-th 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 center coordinates of the b-th main coil in the first transmitting coil, C O2_b (x 2_b , y 2_b ) represents the center coordinates of the b-th main coil in the second transmitting coil, C O3_b (x 3_b , y 3_b ) represents the center coordinates of the b-th main coil in the third transmitting coil. At the same time, it can be seen from Figure 1 that for the innermost main coil in the transmitting coil, that is, the center circular coil, the center coordinates C oi_1 have a winding limit under the condition of satisfying equidistant inward contraction. When the radius of the outermost main coil of the transmitting coil is , the radius of the b-th main coil can be expressed as:

[0053]

[0054] To ensure that the center circular coil has enough space to be wound into a circle under the condition of satisfying an equidistant inward contraction of length d pt , the dimensions of the outermost main coil need to meet the following conditions:

[0055]

[0056] Thus, the trajectory equation of the b-th main coil in the first transmitting coil Coil 1_b (b = 1, 2,..., np )

[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 equation variables.

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

[0064]

[0065] where M bc 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, C b represents the b-th turn of the main coil in the transmitting coil, l b represents the trajectory equation of the b-th turn of the main coil, C c represents the c-th turn of the secondary coil in the receiving coil, l c represents the trajectory equation of the c-th turn of the secondary coil, μ 0 represents the magnetic permeability. The first transmitting coil is located on the XOY plane. Assuming the height of the receiving coil from the XOY plane is z s , R bc represents l b and l c The distance between them, and the calculation formula is

[0066]

[0067] The above is the content of calculating the mutual inductance at any arbitrary coordinate point in space according to the magnetic field coupling space model in step S32.

[0068] The equivalent circuit model of the WPT system of the present invention is built as shown in Figure 2The LCL-LCC type topology 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, according to Kirchhoff's voltage law (KVL), the relationship between current and voltage can be derived as the following formula (10).

[0069]

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

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

[0072]

[0073] Since the parasitic resistance of the compensation inductor is small, neglect R Lr1 , R Lr2 and R Lr3 to simplify equation (10), the input current equation can be obtained as follows:

[0074]

[0075] L p = L p1 = L p2 = L p3 = L pDenotes the inductance of any transmitting coil; The LCL composite resonant network has good robustness and good constant current characteristics for the dynamic change of the load. Therefore, from the perspective of the overall output power of the system, the magnitude of the mutual inductance has little impact on it. Therefore, the secondary resonant current i s Can be expressed as

[0076]

[0077] Wherein, C p = C p1 = C p2 = C p3 , hereinafter, C p Denotes the capacitance at any transmitting coil; M a Represents the mutual inductance between the a-th transmitting coil and the receiving coil, and R Ls Represents the internal resistance of the secondary coil.

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

[0079]

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

[0081]

[0082] L p Denotes the inductance of the transmitting coil, ω denotes the angular frequency, and M as Represents the mutual inductance between the a-th transmitting coil and the overall center coordinates (x s , ys , z s ) mutual inductance between the receiving coils. The output power can be calculated through the above power distribution surface function P(x s , y s , z s ). For the matrix coil, when the coil currents are in phase, the secondary coil obtains the maximum energy, and P target is set as the target output power of the load. At the specified transmission height z s , a plane with the z-axis value of P target (i.e., z = P target ) can be represented as:

[0083]

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

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

[0086]

[0087] Among them,

[0088]

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

[0090] Taking Figure 1 as an example, similarly, for the proposed transmitting mechanism, according to the previous analysis, the center coordinates of each turn of the main coil of the transmitting coil are changing. Starting from equation (2), set C Oa_b (x a_b , y a_b , 0) as 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-th transmitting coil, its lateral offset matrix Φ a_b with the receiving coil can be represented as:

[0091]

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

[0093]

[0094] where represents the mutual inductance calculation function in the magnetic field coupling spatial model, that is, formula (8). Set the power distribution surface function of formula (15) as the power mapping function based on the mutual inductance value. For the convenience of writing, it is denoted as g () , so the power matrix P of the proposed transmitting mechanism can be obtained * n×n expressed as

[0095]

[0096] In fact, the power matrix P * n×n describes the power distribution surface at a given transmission distance z i as shown in Figure 5 . According to formula (21), it can be judged whether the system power transmission capacity reaches the target rated power. For a given z i (z i ∈ z), define the function H() to calculate the number of grid cells with power greater than the rated power P target as follows

[0097]

[0098] where P ij represents the power point at the i-th row and j-th column of the power matrix P * n×n . The above formula calculates the set of all power points P * n×n in the power matrix P ij that are greater than the target rated power P target .

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

[0100]

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

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

[0103] In the present invention, unless otherwise clearly specified and defined, terms such as "installation", "setting", "connection", "fixation", "rotation", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. It can be the internal communication of two components or the interaction relationship between two components. Unless otherwise clearly defined, for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0104] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention 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 is composed of n p >1 turn of main coil is wound, and the centers of all main coils constituting one 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 main coils of each transmitting coil except the outermost main coil are arranged inwardly from the outside to the inside in the direction of the center of gravity of the equilateral triangle at equal distances; The receiving mechanism includes a receiving coil, and the receiving coil is composed of n s The secondary coils are wound in a circle with the same center.

2. A WPT system spatial magnetic focusing enhancement design method based on a thermal matrix coupling mechanism according to claim 1, characterized in that: Let the a=1, 2, 3 transmitting coils be b=1, 2, ..., n from the inside to the outside p The radius and center coordinates of the 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 according to the target application scenario, which include the operating frequency f, 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 ; 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 of the secondary coil of the receiving coil n s , the radius R of each turn of the main coil pb , the distance d between the centers of each two adjacent main coils in the transmitting coil pt , the distance d between the outermost main coils of each two transmitting coils r , the radius of each turn of the secondary coil, the diameter of the main coil itself d wire , the distance d between the centers of each two adjacent main coils in the transmitting coil st ; S3. Calculate the spatial effective charging area according to the spatial effective charging area calculation method and optimize the spatial magnetic focusing of the WPT system.

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

4. A WPT system spatial magnetic focusing enhancement design method according to claim 2, characterized in that: Step S2 specifically includes: S21. According to the coil equivalent center circle principle, 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 effect of mutual modeling, determine the cross-coupling inductance M of the transmitting mechanism t_cross ; S22. Arrange the outermost main coils of the three transmitting coils according to the equilateral polygon principle; establish a Cartesian coordinate system to determine the center coordinates of the outermost main coils of each transmitting coil, and ensure that the three center coordinates satisfy symmetry; S23.Set d pt =0,d r =0, initialize the number of large loops i=1; S24.Set n p =1,n s =1, initialize the number of small loops j = 1; S25. Calculate the cross-inductance between each 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 They respectively represent the cross mutual inductance between the first transmitting coil and the second transmitting coil, between the first transmitting coil and the third transmitting coil, and between the second transmitting coil and the third transmitting coil; S26. Determine whether 0.95M is met target ≤M sum ≤1.05M target If yes, then record the current indicator status A ij , let d pt =d pt +△d pt , △d pt represents the distance increase factor in the main coil, j=j+1, and then execute step S28; if not, set n s =n s +1, then execute step S27; the indicator conditions include d pt ,d r 、n p and n s The current values ​​of these 4 parameters; S27. Determine whether it is satisfied If yes, execute step S25, if no, execute step S28; S28. Let n p =n p +1,n s =1; Determine whether If yes, then execute step S25, if no, then execute step S29; S29. Select the optimal indicator in the current i-th large cycle and determine whether the optimal indicator meets 0.95M t_cross ≤M sum ≤1.05M t_cross If yes, then set the heat matrix coupling mechanism parameters according to the optimal indicator. If no, set i=i+1, d p =0,d r =d r +△d r , execute step S24; where △d r Indicates the factor of increasing the outer distance of the main coil.

5. A WPT system spatial magnetic focusing enhancement design method according to claim 2, characterized in that: Step S3 specifically includes: S31. Construct the equivalent circuit model of the WPT system and set 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 R p1 , R p2 , R p3 , the internal resistance of the receiving coil is R Ls ; The capacitances at the three transmitting coils are C p1 , C p2 , C p3 , the compensation inductances are L r1 , L r2 , L r3 , the internal resistance of the compensation inductor is R Lr1 , R Lr2 , R Lr3 The series compensation capacitor, parallel compensation capacitor and compensation inductor at the receiving coil are C s , C sr , L sr ; Set 4 switches S1-S4 on the transmitting coil side and set a filter capacitor C 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 They represent the currents flowing through the first, second, and third transmitting coils respectively; i1, i2, and i3 represent the currents flowing through the first, second, and third compensation inductors respectively, i s represents the current flowing through the receiving coil, i sr Indicates the input current of the rectifier bridge; u in is the square wave voltage output by the inverter, u s is the input voltage of the rectifier circuit, C r is the filter capacitor, R o For load; S32. Construct a magnetic field coupling space model according to the basic parameters of the heat matrix coupling mechanism set in step S2, and calculate the mutual inductance of any coordinate point in space; S33 constructs a power distribution surface function to calculate the output power and sets the target rated power; S34. According to the given coil size, three n-dimensional vectors x, y and z, and the spatial grid size σ are defined; combined with the magnetic field coupling spatial model, the spatial mutual inductance matrix of each transmitting coil is calculated; S35. Based on the spatial mutual inductance matrix and combined with the power distribution surface function, the power matrix of the transmitting mechanism is calculated; and the volume of the effective spatial charging area is calculated according to the power matrix.

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

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

8. A WPT system spatial magnetic focusing enhancement design method according to claim 5, characterized in that: Step S34 specifically includes: Define three n-dimensional vectors x, y and z as x=[x1 x2x n ],y=[y1 y2y n ],z=[z1 z2z n ] in, x i Represents the i-th element of vector x, y i represents the i-th element of vector y, z i Represents the i-th dimension element of vector z; For the bth turn of the main coil among a transmitting coils, the lateral offset matrix Φ between it and the receiving coil is a_b It is expressed as: Among them, (x a_b ,y a_b ,z a_b ) represents the coordinates of the center of the b-th turn of the main coil in the a-th transmitting coil, and e represents a unit vector; The spatial mutual inductance matrix M of the ath transmitting coil in the transmitting mechanism * n×n_a Expressed as in, Represents the mutual inductance calculation function in the magnetic field coupling space model.

9. A WPT system spatial magnetic focusing enhancement design method according to claim 5, characterized in that: The power matrix is ​​expressed as Among them, P * n×n represents the power matrix, a represents the number of transmitting coils, M * n×n_a represents the spatial mutual inductance matrix, g() represents the power distribution surface function, z i represents the i-th transmission distance; The calculation formula for the effective space charging area volume V is: from:={from1,from2,...,from n } Among them, P target represents the target rated power, H() is a function used to calculate the number of grid cells whose surface power of the power distribution is greater than the target rated power threshold, z represents the transmission distance set, n represents the number of dimensions, and σ represents the spatial grid size.

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