A method for designing parameters of relay coils of a multi-relay wireless power supply system

Abstract

The application relates to the technical field of wireless power supply, and particularly discloses a relay coil parameter design method of a multi-relay wireless power supply system. out , the number of turns N t , the turn spacing d and the working frequency w of the system are optimized under the constraint conditions, and the optimal parameter combination is obtained. out , the number of turns N t , the turn spacing d and the working frequency w of the system are automatically optimized within the limited range, so that the output power of the system meets the design requirements, and the energy transmission efficiency of the system is the highest.

Description

Technical Field

[0001] This invention relates to the field of wireless power supply technology, and in particular to a method for designing relay coil parameters in a multi-relay wireless power supply system. Background Technology

[0002] Wireless power supply systems utilize the principle of near-field coupling in high-frequency electromagnetic fields, using a high-frequency magnetic field as the transmission medium to achieve wireless power transmission through magnetic field coupling between coils. A common multi-relay wireless power supply system mainly consists of three parts: a transmitting coil connected to the power source, a relay coil for energy transmission, and a receiving coil located on the load side. Energy is transferred from the transmitting coil, through the relay coil, to the receiving coil on the other side via electromagnetic induction. Using multi-relay wireless systems for power supply is a novel power supply method for online monitoring equipment of high-voltage transmission lines, offering advantages such as being unaffected by weather and having low maintenance costs.

[0003] Typically, when using a multi-relay wireless power supply system to power equipment, improper selection of relay coil parameters can lead to the system's output power failing to meet design requirements or low energy transfer efficiency, ultimately causing the equipment to malfunction or generate significant energy loss.

[0004] Therefore, when designing the parameters of a repeater coil, it is essential not only to ensure that the system's output power meets design requirements, but also to maximize the system's energy transfer efficiency. Furthermore, the size and number of repeater coils, as well as the system's operating frequency, must be within constraints. Thus, designing repeater coil parameters involves considering numerous factors, making it a challenging yet highly valuable task. Summary of the Invention

[0005] This invention provides a method for designing relay coil parameters in a multi-relay wireless power supply system. The technical problem it solves is to optimize the relay coil parameters so that, under the constraint conditions, the power output of the multi-relay wireless power supply system meets the design requirements and the energy transfer efficiency of the system reaches its maximum.

[0006] To address the above technical problems, this invention provides a method for designing relay coil parameters in a multi-relay wireless power supply system. The coupling mechanism of the multi-relay wireless power supply system includes n coupling coils, which consist of one transmitting coil, n-2 coaxially placed relay coils, and one receiving coil arranged in sequence. The key aspect is that the relay coil parameter design method includes the following steps:

[0007] S1. Establish calculation models for the internal resistance, self-inductance, and mutual inductance of the relay coils in a multi-relay wireless power supply system under high-frequency operating conditions.

[0008] S2. Based on the SS-type compensation topology of the relay coil loop, and combined with KVL law, establish the power loss model and energy transfer efficiency model of the multi-relay wireless power supply system.

[0009] S3. Adjust the number of relay coils (n-2) and outer diameter (r) according to actual conditions and system operating capacity. out Number of turns N t The system limits the turn spacing d and the system operating frequency w, while also limiting the system output power P. out Configure settings;

[0010] S4. Using the particle swarm optimization algorithm, combined with the established internal resistance calculation model, mutual inductance calculation model, and self-inductance calculation model of the relay coil, and taking the system's energy transfer efficiency model as the objective function, under the constraints of n and r... out N t Within the range of d and w, the output power P is limited. out The optimal parameter combination for the relay coil is obtained by optimizing the parameter combination.

[0011] Further, in step S1, the internal resistance calculation model of the relay coil is expressed as:

[0012] When the relay coil is energized with high-frequency alternating current, the internal resistance R of the relay coil depends on the AC internal resistance Rc. prox AC internal resistance R prox The average magnetic field strength of each turn of the Litz wire cross section of the relay coil is calculated using the following theory of AC internal resistance of the coupled coil:

[0013]

[0014] Where n0, r s These represent the number of shares and the radius of a single share in the Leeds Line. Let be the square of the average magnetic field strength on the cross-section of the i-th turn of the coil, ω and I be the angular frequency and effective value of the alternating current flowing through the coil, respectively, u0 and σ be the permeability of free space and the conductivity of the copper wire, respectively, and r be the magnetic field strength of the coil. i Let r be the radius of the i-th turn of the coil. i The calculation formula is as follows:

[0015] r i =r out -(N t -i)*d

[0016] Furthermore, Calculated using the following formula:

[0017]

[0018] in, Let r be the square of the average magnetic field strength on the cross-section of the i-th turn of the coil. c Let be the radius of the i-th turn of the coil cross-section; 'a' is the sampling point along the radian angle of the i-th turn of the coil cross-section; 'b' is the sampling point on the radius corresponding to that radian angle. Six sampling points are taken along the radian angle of the i-th turn of the coil cross-section, corresponding to a = 1, 2, 3, 4, 5, 6, with a sampling step size of π / 4 (excluding 0 and π). Four sampling points are taken on the radius corresponding to each radian angle, corresponding to b = 0, 1, 2, 3, with a sampling step size of 7r. c / 24, therefore, the cross-section of this coil has a total of 24 sampling points; W b The coefficients in the four-node Newton-Cotes integral formula; if the sample point coordinates are (ρ b ,θ a ), then ρ b Let θ be the length of the sample point in the radial direction of the i-th turn of the coil cross-section. a H is the angle of the sample point in the radian direction of the i-th turn of the coil cross-section. 2 (ρ b ,θ a ) represents the square of the magnetic field strength at the sample point.

[0019] Further, in step S1, the self-inductance calculation model of the relay coil is expressed as:

[0020]

[0021] Where L represents the self-inductance of the relay coil, L ii M represents the self-inductance of the i-th turn of the coil. ij This represents the mutual inductance between the i-th turn and the j-th turn of the current relay coil;

[0022] When r i =r j At that time, r i r represents the radius of the i-th turn of the current relay coil. j L represents the radius of the j-th turn of the current relay coil. ii Calculated by the following formula:

[0023]

[0024] Where r represents the radius of integration of the surface integral, and θ represents the angle of integration of the surface integral, when r i <r j At that time, M ij Calculated by the following formula:

[0025]

[0026] Further, in step S1, the mutual inductance calculation model between two adjacent relay coils is expressed as follows:

[0027]

[0028] Where e represents the natural base, v is the spacing between two adjacent relay coils, β is the integral distance of the mutual inductance of each coil turn, and P d P represents the distance between two adjacent repeater coils perpendicular to the axis. d =0, J0() and J1() represent the first-order 0 Bessel function and the first-order 1 Bessel function of the first kind, respectively.

[0029] Furthermore, in step S2, the output power model of the multi-relay wireless power supply system is expressed as:

[0030]

[0031] Where, p out I represents the output power of a multi-relay wireless power supply system. n R represents the current flowing through the load at the receiving end. L Indicates the load resistance;

[0032] The energy transfer efficiency model for a multi-relay wireless power supply system is expressed as follows:

[0033]

[0034] Where I1 represents the current output by the transmitter inverter, U1 represents the output voltage of the inverter, and the output voltage of the inverter is a square wave, with the effective value of the voltage approximating the DC input voltage U. dc ;

[0035] The current in each coupled coil and the current flowing through the load during operation are calculated using the following equations:

[0036]

[0037] Among them, L x Let C be the self-inductance value of the x-th coupled coil. x M represents the resonant capacitance value associated with the x-th coupling coil. xy R represents the mutual inductance between the x-th coupled coil and the y-th coupled coil. x R is the internal resistance value of the x-th coupling coil during operation. eq Let x,y = 1, 2, ..., n, and x ≠ y.

[0038] Furthermore, in step S3, the number of relay coils n-2 and the outer diameter r are... out Number of turns N tThe system is limited by the turn spacing d and the operating frequency w, specifically as follows:

[0039] Based on actual needs, material costs, weight requirements of the coupling mechanism, and insulator skirt dimensions, determine the maximum and minimum values ​​of the number of repeater coils n-2 and the outer turn radius r. out The maximum value r outmax and minimum value;

[0040] Determine the minimum value of the turn spacing d for the relay coil under close winding conditions:

[0041] d min =2*r c

[0042] Determine the number of turns N under the conditions of maximum outer turn radius and minimum turn spacing. t Maximum value:

[0043] N tmax =r outmax / d min

[0044] Based on the actual operating capacity of the inverter and the coupling effect of the relay coil, determine the maximum and minimum operating frequencies of the system.

[0045] Furthermore, step S4 specifically includes the following steps:

[0046] S41. Determine the multi-relay wireless power supply system excluding n and r. out N t Parameters other than d and w are used to initialize the initial values ​​of the particles and the optimization boundary, and to determine the maximum number of iterations T.

[0047] S42. Calculate n and r for each particle. out N t The combination of parameters d and w;

[0048] S43. Calculate the objective function value corresponding to the particle;

[0049] S44, Update particle parameter combination;

[0050] S45. Does the combination of particle parameters exceed the limit? If so, set the particle parameters to the limit value and proceed to the next step; otherwise, proceed directly to the next step.

[0051] S46. Determine whether the maximum number of iterations has been reached. If so, take the current particle's parameter combination as the optimal parameter combination and proceed to the next step. Otherwise, return to step S42.

[0052] S47. Under the current optimal parameter combination, has the output power of the multi-relay wireless power supply system reached the set value? If so, output the current optimal particle parameter combination and DC input voltage U. dc Otherwise, adjust the DC input voltage and return to step S42.

[0053] The present invention provides a method for designing relay coil parameters for a multi-relay wireless power supply system, the advantages of which are:

[0054] By modeling the system, we obtained the internal resistance calculation model, self-inductance calculation model, and mutual inductance calculation model of the repeater coils in a multi-relay wireless power supply system under high-frequency operating conditions. We also obtained the power loss model and energy transfer efficiency model of the multi-relay wireless power supply system. Based on actual conditions, we constructed constraints. Finally, using a particle swarm optimization algorithm with the system's energy transfer efficiency model as the objective function, we optimized the number of repeater coils (n-2) and their outer diameter (r) under the constructed constraints. out Number of turns N t The optimal parameter combination is obtained by optimizing the turn spacing d and the system operating frequency w. This method can achieve optimization of the number of relay coils n-2 and the outer diameter r within the constraints. out Number of turns N t The system automatically optimizes the turn spacing d and the system operating frequency w to ensure that the system output power meets the design requirements while maximizing the system's energy transfer efficiency. Attached Figure Description

[0055] Figure 1 This is a circuit diagram of a multi-relay wireless power supply system provided in an embodiment of the present invention;

[0056] Figure 2 This is provided by the embodiments of the present invention. Figure 1 The equivalent circuit diagram;

[0057] Figure 3 This is a sampled image of the Litz wire cross section during the relay coil internal resistance modeling process provided in this embodiment of the invention;

[0058] Figure 4 This is a flowchart of iterative optimization of the design parameters of the coupling coil using the particle swarm optimization algorithm, provided in an embodiment of the present invention. Detailed Implementation

[0059] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0060] Figure 1The diagram shown is a typical circuit diagram of a multi-relay wireless power supply system. The DC input voltage of this system is U. dc S on the left a S b S c S d The inverter circuit consists of four thyristors and has an output voltage of U1. The middle section is a coupling mechanism composed of multiple coupling coils. This coupling mechanism includes n coupling coils: one transmitting coil arranged sequentially, n-2 coaxially placed relay coils, and one receiving coil. L... x C x R x I x M represents the inductance, capacitance, internal resistance, and current values ​​present in the x-th coupled coil circuit. xy This represents the mutual inductance between the x-th coupled coil and the y-th coupled coil, where x, y = 1, 2, ..., n, and x ≠ y. The right side shows a bridge rectifier circuit composed of four diodes, D1, D2, D3, and D4. The input voltage of the rectifier circuit is U. n The output of the rectifier circuit passes through capacitor C. d After filtering, it is directly connected to the load R. L U o The voltage across the load is approximately equal to U. n I o The value of the current flowing through the load is approximately equal to I. n .

[0061] Figure 2 As shown Figure 1 The equivalent circuit diagram, where the subsequent circuit of the receiving coil is equivalent to the load R. eq In practice, the internal resistance of a bridge rectifier circuit is very small, therefore R eq The value is approximately equal to the load resistance R. L .

[0062] for Figure 1 , Figure 2 The multi-relay wireless power supply system shown in this embodiment of the invention provides a method for designing relay coil parameters for such a system. By optimizing the relay coil parameters, the power output of the multi-relay wireless power supply system meets design requirements and maximizes the system's energy transfer efficiency while satisfying constraints. Specifically, the method includes the following steps:

[0063] S1. Establish calculation models for the internal resistance, self-inductance, and mutual inductance of the relay coils in a multi-relay wireless power supply system under high-frequency operating conditions.

[0064] S2. Based on the SS-type compensation topology of the relay coil loop, and combined with KVL law, establish the power loss model and energy transfer efficiency model of the multi-relay wireless power supply system.

[0065] S3. Adjust the number of relay coils (n-2) and outer diameter (r) according to actual conditions and system operating capacity. out Number of turns N t The system limits the turn spacing d and the system operating frequency w, while also limiting the system output power P. out Configure settings;

[0066] S4. Using the particle swarm optimization algorithm, combined with the established internal resistance calculation model, mutual inductance calculation model, and self-inductance calculation model of the relay coil, and taking the system's energy transfer efficiency model as the objective function, under the constraints of n and r... out N t Within the range of d and w, the output power P is limited. out The optimal parameter combination for the relay coil is obtained by optimizing the parameter combination.

[0067] (1) Regarding step S1

[0068] Figure 3 Sampling diagram of Litz wire cross section during relay coil internal resistance modeling process. Figure 3 In this equation, h represents the sampling step size in the radial direction of the Litz wire cross-section, θ represents the radian angle of the sample point in the Litz wire cross-section, ρ represents the distance between the sample point and the center point in the Litz wire cross-section, and H(ρ,θ) represents the magnetic field strength at the sample point. In step S1, the internal resistance calculation model of the relay coil is expressed as:

[0069]

[0070] Where R represents the internal resistance of the relay coil, R cond R represents the DC conduction resistance of the Litz wire in the relay coil. prox R represents the AC internal resistance of the relay coil. cond-i R represents the DC conduction resistance of the Litz wire in the i-th turn of the relay coil. prox-i This represents the AC internal resistance of the i-th turn of the relay coil.

[0071] For N t The average magnetic field strength per turn of a Litz wire cross-section in a relay coil is expressed as H. avg The surface integral is converted into sample point numerical calculations using the Newton-Cotes integral formula. Twenty-four sample points are taken at each turn of the Litz line cross section. The Litz line itself and all other Litz lines will generate a radial magnetic field strength Hr and a magnetic field strength Hz perpendicular to the coil plane at each sample point.

[0072]

[0073] in, Let r be the square of the average magnetic field strength on the cross-section of the i-th turn of the coil. c Let be the radius of the i-th turn of the coil cross-section; 'a' is the sampling point along the radian angle of the i-th turn of the coil cross-section; 'b' is the sampling point on the radius corresponding to that radian angle. Six sampling points are taken along the radian angle of the i-th turn of the coil cross-section, corresponding to a = 1, 2, 3, 4, 5, 6, with a sampling step size of π / 4 (excluding 0 and π). Four sampling points are taken on the radius corresponding to each radian angle, corresponding to b = 0, 1, 2, 3, with a sampling step size of 7r. c / 24, therefore, the cross-section of this coil has a total of 24 sampling points; W b =1, 3, 3, 1 (b = 0, 1, 2, 3) are the coefficients in the four-node Newton-Cotes integral formula; if the sample point coordinates are (ρ b ,θ a ), then ρ b Let θ be the length of the sample point in the radial direction of the i-th turn of the coil cross-section. a H is the angle of the sample point in the radian direction of the i-th turn of the coil cross-section. 2 (ρ b ,θ a ) represents the square of the magnetic field strength at the sample point.

[0074] The average magnetic field strength of the Litz wire cross-section is obtained by summing the magnetic field strengths of 24 sample points per turn and dividing by the cross-sectional area of ​​the Litz wire. Finally, the AC internal resistance R of the coupling coil is calculated according to the following theory of AC internal resistance of relay coil. prox :

[0075]

[0076] Where n0, r s Let ω and I represent the number of strands and radius of a single strand of the Litz wire, respectively; ω and I represent the angular frequency and effective value of the alternating current flowing through the coil, respectively; u0 and σ represent the permeability of free space and the conductivity of the copper wire, respectively; and r represents the permeability of the copper wire. i Let r be the radius of the i-th turn of the coil. i The calculation formula is as follows:

[0077] r i =r out -(N t -i)*d

[0078] For calculating the mutual inductance of a relay coil, when the number of turns of a coil is N... t The radius of the i-th turn is r i The other set of coils has N turns. t The radius of the j-th turn is r jThe horizontal spacing between each relay coil is v, and the axial spacing is p. d At that time, the mutual inductance M between the two relay coils is integrated using the Bessel function to obtain the mutual inductance value of the relay coils:

[0079]

[0080] Where e represents the natural base, v is the spacing between two adjacent relay coils, β is the integral distance of the mutual inductance of each coil turn, and P d P represents the distance between two adjacent repeater coils perpendicular to the axis. d =0, J0() and J1() represent the first-order 0 Bessel function and the first-order 1 Bessel function of the first kind, respectively.

[0081] For calculating the self-inductance of a relay coil, considering that the i-th turn of the Litz wire itself has a magnetic flux, and the j-th turn of the Litz wire will also generate a magnetic flux inside the i-th turn of the Litz wire, the self-inductance of the relay coil is derived using the Biot-Saffar law, which states that it is equal to the sum of the mutual inductance and self-inductance of each turn of the Litz wire:

[0082]

[0083] Where L represents the self-inductance of the relay coil, L ii M represents the self-inductance of the i-th turn of the coil. ij φ represents the mutual inductance between the i-th turn and the j-th turn. ii Let φ represent the magnetic flux produced within the i-th turn of the Litz wire. ij This represents the magnetic flux generated inside the i-th turn of the Litz line in the j-th turn.

[0084] When the radius of the i-th turn of a relay coil is r i The radius of the j-th turn of the coil is r. j When condition r is met i <r j At that time, the mutual inductance between the two turns of the coil can be obtained using surface integrals:

[0085]

[0086] When condition r is satisfied i =r j At that time, the self-inductance of the i-th turn of the coil can also be calculated using surface integrals:

[0087]

[0088] Where r represents the radius of integration of the surface integral, and θ represents the angle of integration of the surface integral.

[0089] (2) Regarding step S2

[0090] Using the SS-type topology of the relay coil circuit, consider the mutual inductance M between non-adjacent relay coils. ij The influence is thus determined, thereby obtaining the current in each relay coil circuit:

[0091]

[0092] Based on this, and further considering the internal resistance of the coupling coils, a power loss model for n coupling coils is constructed:

[0093]

[0094] Among them, I x R represents the current flowing through the x-th coupling coil. x This represents the internal resistance of the x-th coupling coil;

[0095] The output power of the multi-relay wireless power supply system can also be obtained as follows:

[0096]

[0097] Among them, I n R represents the current flowing through the load at the receiving end. L Representing the load resistance, the energy transfer efficiency model of a multi-relay wireless power supply system can be expressed as:

[0098]

[0099] Where I1 represents the current output by the transmitter inverter, and U1 represents the inverter's output voltage, which is approximately equal to the system's DC input voltage U. dc In practical applications, after the maximum energy transfer efficiency of the system is obtained, the output power can be adjusted by changing the DC input voltage, so that the output of the system can better meet the actual needs.

[0100] (3) Regarding step S3

[0101] For the number of relay coils n-2, the outer diameter r out Number of turns N t The system is limited by the turn spacing d and the operating frequency w, specifically as follows:

[0102] Based on actual needs, material costs, weight requirements of the coupling mechanism, and insulator skirt dimensions, determine the maximum and minimum values ​​of the number of repeater coils n-2 and the outer turn radius r. out The maximum value r outmax and minimum value;

[0103] Determine the minimum value of the turn spacing d for the relay coil under close winding conditions:

[0104] d min =2*r c

[0105] Determine the number of turns N under the conditions of maximum outer turn radius and minimum turn spacing. t Maximum value:

[0106] N tmax =r outmax / d min

[0107] Based on the actual operating capacity of the inverter and the coupling effect of the relay coil, determine the maximum and minimum operating frequencies of the system.

[0108] (4) Regarding step S4

[0109] like Figure 4 As shown, step S4 specifically includes the following steps:

[0110] S41. Determine the system excluding n and r. out N t Parameters other than d and w are used to initialize the initial values ​​of the particles and the optimization boundary, and to determine the number of iterations T.

[0111] S42. Calculate n and r for each particle. out N t The combination of parameters d and w;

[0112] S43. Calculate the objective function value corresponding to the particle;

[0113] S44, Update particle parameter combination;

[0114] S45. Does the combination of particle parameters exceed the limit? If so, set the particle parameters to the limit value and proceed to the next step; otherwise, proceed directly to the next step.

[0115] S46. Determine whether the maximum number of iterations has been reached. If so, take the current particle's parameter combination as the optimal parameter combination and proceed to the next step. Otherwise, return to step S42.

[0116] S47. Under the current optimal parameter combination, has the output power of the multi-relay wireless power supply system reached the set value? If so, output the current optimal particle parameter combination and DC input voltage U. dc Otherwise, adjust the DC input voltage and return to step S42.

[0117] In summary, the present invention provides a method for designing relay coil parameters in a multi-relay wireless power supply system. This method involves modeling the system to obtain calculation models for the internal resistance, self-inductance, and mutual inductance of the relay coils under high-frequency operating conditions, as well as the power loss and energy transfer efficiency models of the multi-relay wireless power supply system. Constraints are then constructed based on actual conditions. Finally, a particle swarm optimization algorithm is used, with the system's energy transfer efficiency model as the objective function, to design parameters for the number of relay coils (n-2) and their outer diameter (r) under the constructed constraints. out Number of turns N t The optimal parameter combination is obtained by optimizing the turn spacing d and the system operating frequency w. This method can achieve optimization of the number of relay coils n-2 and the outer diameter r within the constraints. out Number of turns N t The system automatically optimizes the turn spacing d and the system operating frequency w to ensure that the system output power meets the design requirements while maximizing the system's energy transfer efficiency.

[0118] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for designing relay coil parameters in a multi-relay wireless power supply system, wherein the coupling mechanism of the multi-relay wireless power supply system includes n coupling coils, the n coupling coils comprising one transmitting coil arranged sequentially, n-2 coaxially placed relay coils, and one receiving coil, characterized in that, The method for designing relay coil parameters includes the following steps: S1. Establish calculation models for the internal resistance, self-inductance, and mutual inductance of the relay coils in a multi-relay wireless power supply system under high-frequency operating conditions. S2. Based on the SS-type compensation topology of the relay coil loop, and combined with KVL law, establish the power loss model and energy transfer efficiency model of the multi-relay wireless power supply system. S3. Adjust the number of relay coils (n-2) and outer diameter (r) according to actual conditions and system operating capacity. out Number of turns N t The system limits the turn spacing d and the system operating frequency w, while also limiting the system output power. Configure settings; S4. Using the particle swarm optimization algorithm, combined with the established internal resistance calculation model, mutual inductance calculation model, and self-inductance calculation model of the relay coil, and taking the system's energy transfer efficiency model as the objective function, under the constraints of n and r... out N t Within the range of d and w, the output power is limited. The optimal parameter combination for the relay coil is obtained by optimizing the parameter combination. In step S1, the internal resistance calculation model of the relay coil is expressed as follows: When the relay coil is energized with high-frequency alternating current, the internal resistance R of the relay coil depends on the AC internal resistance. internal resistance to communication The average magnetic field strength of each turn of the Litz wire cross section of the relay coil is calculated using the following theory of AC internal resistance of the coupled coil: ， in , These represent the number of shares and the radius of a single share in the Leeds Line. For the first The square of the average magnetic field strength on the cross-section of the coil. and These are the angular frequency and RMS value of the alternating current flowing through the coil, respectively. and These are the vacuum permeability and the electrical conductivity of copper wire, respectively. For the first The radius of the coil, The calculation formula is as follows: 。 2. The method for designing relay coil parameters in a multi-relay wireless power supply system according to claim 1, characterized in that, Calculated using the following formula: ， in, For the first The square of the average magnetic field strength on the cross-section of the coil. For the first The radius of the coil cross-section; For the first Sampling points in the radian angle direction of the coil cross-section For the sampling point on the radius corresponding to that radian angle, at the th Six sampling points are taken along the radian angle of the coil cross-section, corresponding to a=1,2,3,4,5,6, with a sampling step size of [missing value]. It does not contain 0 and At two locations, four sample points are taken on the radius corresponding to each radian angle, corresponding to b=0,1,2,3, with a sampling step size of [missing value]. Therefore, there are a total of 24 sampling points on the cross-section of this coil. 1, 3, 3, 1 are the coefficients in the four-node Newton-Cotes integral formula; if the sample point coordinates are... ,but For this sample point at the th The length of the coil cross-section in the radial direction. For this sample point at the th The angle in the direction of the radian angle of the coil cross-section. The square of the magnetic field strength at the sample point.

3. The method for designing relay coil parameters in a multi-relay wireless power supply system according to claim 2, characterized in that, In step S1, the self-inductance calculation model of the relay coil is expressed as: ， Where L represents the self-inductance of the relay coil, L ii M represents the self-inductance of the i-th turn of the coil. ij This represents the mutual inductance between the i-th turn and the j-th turn of the current relay coil; when At that time, r i r represents the radius of the i-th turn of the current relay coil. j L represents the radius of the j-th turn of the current relay coil. ii Calculated by the following formula: ， Where r represents the radius of integration of the surface integral. The angle representing the integral of the surface integral, when At that time, M ij Calculated by the following formula: 。 4. The method for designing relay coil parameters in a multi-relay wireless power supply system according to claim 3, characterized in that, In step S1, the mutual inductance calculation model between two adjacent relay coils is expressed as follows: ， Where e represents the natural base, The spacing between two adjacent relay coils. The integral distance of the mutual inductance of each turn of the coil. This indicates the distance between two adjacent repeater coils perpendicular to the axis. =0, , Let represent the first-order 0th-order Bessel function and the first-order 1st-order Bessel function, respectively.

5. The method for designing relay coil parameters in a multi-relay wireless power supply system according to claim 4, characterized in that, In step S2, the output power model of the multi-relay wireless power supply system is expressed as: ， in, Indicates the output power of a multi-relay wireless power supply system. R represents the current flowing through the load at the receiving end. L Indicates the load resistance; The energy transfer efficiency model for a multi-relay wireless power supply system is expressed as follows: ， in, This indicates the current output by the transmitter inverter. This indicates the output voltage of the inverter, which is a square wave. The current in each coupled coil and the current flowing through the load during operation are calculated using the following equations: ， in, For the first The self-inductance of the coupling coil, Indicates the relationship with the first The resonant capacitance value associated with each coupling coil Indicates the first The first coupling coil and the second Mutual inductance between the coupled coils For the first time during the work process The internal resistance value of each coupling coil, Let x,y = 1, 2, ..., n, and x ≠ y.

6. The method for designing relay coil parameters in a multi-relay wireless power supply system according to claim 5, characterized in that, In step S3, the number of relay coils n-2 and the outer diameter r are... out Number of turns N t The system is limited by the turn spacing d and the operating frequency w, specifically as follows: Based on actual needs, material costs, weight requirements of the coupling mechanism, and insulator skirt dimensions, determine the maximum and minimum values ​​of the number of repeater coils n-2 and the outer turn radius. maximum value and minimum value; Determine the turn spacing of the relay coil under close winding conditions. Minimum value: ， Determine the number of turns under the conditions of maximum outer turn radius and minimum turn spacing. Maximum value: ， Based on the actual operating capacity of the inverter and the coupling effect of the relay coil, determine the maximum and minimum operating frequencies of the system.

7. A method for designing relay coil parameters in a multi-relay wireless power supply system according to any one of claims 1 to 6, characterized in that, Step S4 specifically includes the following steps: S41. Determine the multi-relay wireless power supply system excluding n and r. out N t Parameters other than d and w are used to initialize the initial values ​​of the particles and the optimization boundary, and to determine the maximum number of iterations T. S42. Calculate n and r for each particle. out N t The combination of parameters d and w; S43. Calculate the objective function value corresponding to the particle; S44, Update particle parameter combination; S45. Does the combination of particle parameters exceed the limit? If so, set the particle parameters to the limit value and proceed to the next step; otherwise, proceed directly to the next step. S46. Determine whether the maximum number of iterations has been reached. If so, take the current particle's parameter combination as the optimal parameter combination and proceed to the next step. Otherwise, return to step S42. S47. Under the current optimal parameter combination, has the output power of the multi-relay wireless power supply system reached the set value? If so, output the current optimal particle parameter combination and DC input voltage. Otherwise, adjust the DC input voltage and return to step S42.

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