Anti-offset coil and design method thereof

Abstract

The invention discloses an anti-offset coil and a design method thereof, and the method comprises the steps: coil structure design, coil parameter modeling, ss compensation topological structure selection, and ss-type wireless power transmission system construction for simulation verification. Hexagonal coils are adopted as research objects, the hexagonal coils are subjected to combined design, and the designed coils are modeled; mutual inductance and self-inductance parameters of a coil are analyzed, a simulation circuit is built, it can be known from a magnetic induction distribution cloud picture that the proposed coupling mechanism can generate a uniform magnetic field in a charging area above a transmitting end, the anti-offset capability is remarkably enhanced, and it is obtained through simulation that in the transverse + / -80 mm offset and the longitudinal + / -40 mm offset, the anti-offset capability is remarkably improved. The range system can maintain the output power of 300W and the efficiency is not lower than 80%, when the receiving coil deviates by 120 degrees from the X axis, the transmission characteristic of the system is consistent with the characteristic when the receiving coil deviates along the X axis, and the Y axis also has the characteristic, so that the system has key guiding significance for solving the endurance problem of the unmanned aerial vehicle.

Description

Technical Field

[0001] This invention belongs to the field of drone charging technology, specifically relating to an anti-offset coil and its design method. Background Technology

[0002] With the rapid maturation and application of technologies such as drone platforms, sensors, and artificial intelligence, as well as the promotion of intelligent transformation and policy support in the power industry, drones have become an indispensable core technology for modern power inspection due to their significant advantages in safety, efficiency, accuracy, and economy. Wireless power transfer technology can effectively overcome the various drawbacks of wired charging, providing a new approach to addressing drone endurance issues. This technology enables drones to achieve flexible energy replenishment, significantly extending their flight time while greatly simplifying maintenance and operation procedures. When a drone lands on a wireless charging platform, external environmental factors or insufficient landing accuracy may cause the coupling mechanism to shift. This shift weakens the system's coupling strength, leading to instability in the charging process. To address these issues, coupling mechanism design, compensation topology optimization design, and control strategy improvement all contribute to enhancing the system's anti-shift performance. Compared to the other two solutions, coupling mechanism design has become an important research direction in the field of wireless power transfer.

[0003] In the existing technology, single discrete solenoid coils have excellent horizontal longitudinal anti-offset performance, but their horizontal lateral anti-offset performance still needs to be improved. Double-layer orthogonal DD coils eliminate the central magnetic field induction blind zone, but their anti-offset performance is poor when the angle is offset. In addition to designing the coupling mechanism, additional alignment work can be used to achieve adaptive position correction, but the accuracy of coil position sensing is not reliable under outdoor conditions.

[0004] To address the issue of system output under arbitrary coil offset without introducing complex control, this paper proposes an anti-offset coil and its design method. Compared with traditional coils, it can achieve a wider range of decoupling, smooth the decreasing trend of coupling coefficient when the coil is offset, and improve the system's anti-offset capability, thus providing a foundation for the design of subsequent wireless power transmission systems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is an anti-offset coil and its design method, which can maintain a constant coupling coefficient and stable transmission efficiency.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: An anti-offset coil and its design method, comprising the following steps: S1, LTL-HexTri coil structure design; S2, LTL-HexTri coil parameter modeling; S3. Select the SS compensation topology and build an SS-type wireless power transmission system for simulation verification.

[0007] S1 includes: S1.1, identifying the research object; S1.2, finite element simulation software is used to simulate and obtain the magnetic induction intensity distribution cloud map of tightly wound and loosely wound coils, and further analysis is used to select the winding method; S1.3, finite element simulation software was used to simulate and obtain the magnetic induction intensity distribution cloud map of different coil numbers, and further analysis was conducted to select the winding method.

[0008] The anti-offset coil is an LTL-HexTri, a loose-tight triangular hexagonal coil designed by combining hexagonal coils, with hexagonal coils as the research object.

[0009] S2 includes: S2.1, simplifying the outer, inner, and middle coils of the LTL-HexTri coil into a coupling mechanism diagram; S2.2, Calculation parameters, including the magnetic induction intensity and magnetic flux generated by the outer, middle and inner coils of the single hexagonal coil at the transmitting end in the Z-axis direction, the mutual inductance of the combined coils at the transmitting end, and the total self-inductance at the transmitting end.

[0010] S2.2 calculates the magnetic induction intensity generated by the outer, middle, and inner coils of a single hexagonal coil in the Z-axis direction. According to Biot's law, for a finite-length straight conductor, the magnitude of the magnetic induction intensity generated at any point is: (1); In the formula: D is the vertical distance from the conductor to the magnetic field calculation point, and θ is the angle between the conductor and the position vector of any point; ρ is the permeability of free space; I is the current flowing through the wire; The analysis focuses only on the single hexagonal coil at the transmitting end, selecting the external coil wire. Middle coil internal coil Assuming Coordinates are ,but Coordinates are ; Coordinates are , Coordinates are ; Coordinates are , Coordinates are ; Combine any point Substituting into the formula, we can see that: The magnitude of the magnetic induction intensity generated at point P , The magnitude of the magnetic induction intensity generated at point P , The magnitude of the magnetic induction intensity generated at point P : (2); (3); (4).

[0011] Further calculation of the conductor , , A magnetic field strength is generated in the z-direction at point P. , , : (5); (6); (7); Therefore, the magnetic induction intensities generated by the outer, middle, and inner coils in the Z-axis direction are respectively , , As shown in the following formula: (8); (9); (10); In the formula: , , , , , These represent the magnetic induction intensity generated by each side of the outer hexagonal coil in the Z-axis direction; , , , , , These represent the magnetic induction intensity generated by each side of the central hexagonal coil in the Z-axis direction; , , , , , These represent the magnetic induction intensity generated by each side of the internal hexagonal coil in the Z-axis direction.

[0012] S2.2 calculates the magnetic flux generated in the Z-axis direction by the outer, middle, and inner coils of the single hexagonal coil and the mutual inductance of the combined coils. The receiving coil is divided into four regions, and the coils are labeled with the following outer diameters of the hexagonal coils: , , The inner diameters of the hexagonal coils are as follows: , , , The side length of the outer hexagon , The side length of the central hexagon , The side length of the inner hexagon , , , These are the specific numerical values ​​for the number of turns on the outer, middle, and inner sides of the coil, respectively. The diameter of the wire. The external coil turn spacing, The pitch is the internal coil turn spacing, and j, g, and k represent the number of turns of the corresponding coil, respectively; The magnetic flux generated by the outer coil of the transmitting coil in various parts of the receiving coil is calculated using the following formula: (11); (12); (13); In the formula: , , The magnetic flux generated by the outer coil of the transmitting coil on the outer, middle, and inner coils of the receiving coil, respectively; , , , For the boundary function of the external coil; , , , The boundary function of the middle coil; , , , For the boundary function of the internal coil; The magnetic flux density generated by the external coil of the transmitting coil; The magnetic flux generated by the central coil of the transmitting coil in various parts of the receiving coil is shown in the following formula: (14); (15); (16); In the formula: , , The magnetic flux generated by the middle coil of the transmitting coil to the outer, middle, and inner coils of the receiving coil, respectively; The magnetic flux generated by the internal coil of the transmitting coil in various parts of the receiving coil is shown in the following formula: (17); (18); (19); In the formula: , , The magnetic flux generated by the internal coil of the transmitting coil to the external, middle, and internal coils of the receiving coil, respectively; Based on the above analysis, the formula for mutual inductance can be obtained as follows: (20); In the formula: This is the total mutual inductance between the transmitting and receiving coils; , , These are the specific numerical values ​​for the number of turns on the outside, middle, and inside of the coil, respectively. , , The magnetic flux generated by the outer coil of the transmitting coil on the outer, middle, and inner coils of the receiving coil, respectively; , , The magnetic flux generated by the middle coil of the transmitting coil to the outer, middle, and inner coils of the receiving coil, respectively; , , The magnetic flux generated by the internal coil of the transmitting coil to the external, middle, and internal coils of the receiving coil, respectively; This is the current flowing through the transmitting coil.

[0013] In S2.2, the total self-inductance L1 of the entire transmitting end is the sum of the self-inductances of the three coils plus their mutual inductance. For a single hexagonal LTL coil, its self-inductance is: (twenty one); In the formula: The self-inductance of an LTL coil of any individual hexagon; For the mutual inductance between the internal and central coils of a single hexagon; For the mutual inductance between the internal and external coils of a single hexagonal coil; The mutual inductance between the middle and outer coils of a single hexagonal coil; The self-inductance of the external coil; The self-inductance of the middle coil; The internal coil's self-inductance; If three coils are connected in series and driven in phase, the total self-inductance at the transmitter is: (twenty two); In the formula: The total self-inductance of the transmitting coil; For the self-inductance of an arbitrary individual hexagonal LTL coil, It is the mutual inductance between coil A and coil B; It is the mutual inductance between coil A and coil C; It is the mutual inductance between coil B and coil C; It is the total mutual inductance between any two transmitting coils, that is, the coupling between their respective outer loop, middle loop, and inner loop; The self-inductance of coil A; The self-inductance of coil B; The self-inductance of coil C; Formula for the self-inductance of a hexagonal coil: (twenty three); In the formula: L represents the self-inductance of the hexagonal coil, Permeability of free space; This refers to the number of coil turns. The average diameter of the coil; The fill factor; , , , These are coefficients specific to hexagons, and all are constants; This is a shape scaling factor, which is related to the integral of the total number of turns and the average diameter of the coil; For logarithmic geometric corrections, the cross-geometric mean distance between turns is correlated; The coefficient of the linear term is usually ignored because the hexagon has symmetry, which causes the linear terms to cancel each other out. For edge correction of quadratic terms; The formula for average diameter is: (twenty four); The formula for the fill factor is: (25); In the formula: The inner diameter of the coil; This is the outer diameter of the coil.

[0014] S3 includes: S3.1, Selecting the SS-type compensation topology, the coils at both the transmitting and receiving ends are connected in series with capacitors. By adjusting the parameters of the capacitors, the system can operate at a specific resonant frequency, achieving efficient energy transfer. S3.2, Build the simulation model; S3.3, Compare and analyze the changes in coupling coefficient k of the coupling mechanism with transmission distance before and after optimization.

[0015] The S3.2 simulation model includes a high-frequency inverter, a transmitting coil, a receiving coil, and a compensation capacitor.

[0016] The main beneficial effects of this invention are as follows: 1) Significantly improved anti-offset performance, addressing the core pain point of charging stability: Excellent magnetic field uniformity and coupling stability: Utilizing a loosely wound, triangular hexagonal LTL-HexTri structure, the natural symmetry of the three hexagonal coils arranged in a triangular pattern, combined with a loose outer layer, a tight middle layer, and a loose inner layer, creates a uniform magnetic field in the charging area above the transmitter. Compared to traditional single discrete solenoid coils and double-layer orthogonal DD coils, this design effectively eliminates the magnetic field induction blind zone. When the receiving coil deviates, the magnetic field superposition effect mitigates the decrease in coupling coefficient. Simulation data shows that the optimized coil improves the coupling coefficient by 23.8% at a transmission distance of 2cm and by 18.5% at 16cm, significantly enhancing the system's tolerance to deviation.

[0017] Maintaining high-efficiency transmission over a wide range of offsets: In actual drone landing offset scenarios, the system can still stably maintain an output power of 300W with a transmission efficiency of no less than 80% within a horizontal offset range of ±80mm and a vertical offset range of ±40mm. At the same time, due to the triangular structure characteristics of the transmitting coil, the transmission characteristics remain consistent when the receiving coil is offset along the X-axis or 120° away from the X-axis. The same applies to the Y-axis direction, which completely solves the limitation of traditional coils that are "strong in single-direction offset resistance but weak in multiple directions", and adapts to the actual needs of drones landing at any angle.

[0018] 2) The technical design balances practicality and cost-effectiveness, lowering the barrier to implementation: Balancing structural simplification with controllable costs: In selecting the number of coil combinations, the magnetic induction distribution of two-coil and three-coil combinations was compared through simulation, and three-coil combinations were determined to be the optimal solution. This ensures both uniform magnetic field distribution and avoids increased design complexity and manufacturing costs caused by too many coils. The selection of coil parameters takes into account both transmission performance and processing feasibility, eliminating the need for special customized materials and reducing the difficulty of mass production.

[0019] Highly adaptable to topology and easy to integrate into existing systems: The wireless power transmission system is built using the SS compensation topology. This topology has a simple structure, low control difficulty, and can maintain a stable output voltage when the load changes. It can be directly adapted to the high-frequency inverter and rectifier filter module of the existing wireless charging platform for drones without large-scale hardware modification, thus shortening the technology implementation cycle.

[0020] 3) Support upgrades to drone battery life and promote the expansion of industry applications: Breaking the bottleneck of drone endurance: Through stable wireless charging technology, drones do not need to rely on fixed charging points and manual operation, and can achieve "on-demand charging" in tasks such as inspection and mapping, significantly extending the duration of a single mission; at the same time, the anti-deviation performance avoids charging failures caused by insufficient landing accuracy, reduces the number of times the drone has to return to base, and improves operational efficiency.

[0021] Adaptable to complex outdoor scenarios: To address the issue of drone landing deviation caused by factors such as wind and terrain during outdoor inspections, this design eliminates the need for additional position sensing and adaptive correction devices to avoid the problem of unreliable outdoor sensing accuracy. Stable charging can be achieved simply by optimizing the coil structure. It can be widely used in outdoor scenarios such as power line inspection, forest fire prevention, and urban security, providing key technical support for the intelligent transformation of the drone industry. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 Schematic diagram of coil structure.

[0023] Figure 2 Tightly wound magnetic induction distribution cloud map.

[0024] Figure 3 Magnetic induction distribution cloud map of loosely wound coil.

[0025] Figure 4 Magnetic induction distribution cloud map of combined wound coils.

[0026] Figure 5 Schematic diagram of a double-coil combined winding structure.

[0027] Figure 6 Schematic diagram of a three-coil combined winding structure.

[0028] Figure 7 Three-coil magnetic induction distribution cloud map.

[0029] Figure 8 Simplified diagram of the coupling mechanism.

[0030] Figure 9 Diagram showing the division of the receiving coil area.

[0031] Figure 10Equivalent circuit diagram.

[0032] Figure 11 Simulation model.

[0033] Figure 12 The coupling coefficient varies with the transmission distance.

[0034] Figure 13 Output power varies with longitudinal offset.

[0035] Figure 14 Output power varies with lateral offset. Detailed Implementation

[0036] An anti-offset coil and its design method include the following steps: S1, LTL-HexTri coil structure design; S2, LTL-HexTri coil parameter modeling; S3. Select the SS compensation topology and build an SS-type wireless power transmission system for simulation verification.

[0037] Preferably, such as Figure 1 As shown, S1 includes: S1.1, determining the research object. Since a regular hexagon is a regular polygon that can be seamlessly tiled, and the gap between units is close to zero, it has a natural advantage in array layout. Compared with traditional circular and rectangular arrays, a regular hexagonal array can achieve isotropic coverage of the magnetic field on the horizontal plane while eliminating the azimuth dead zone. At the same time, the inherent gap of a circular array leads to wasted area, and there is a ring-shaped weak coupling region in the edge magnetic field. Although a rectangular array can be fully tiled, the magnetic field at right angles is sharply distorted, and the offset tolerance drops sharply. Therefore, a hexagonal coil is used as the research object, and on this basis, hexagonal coils are combined. The designed loose-tight triangular hexagonal coil LTL-HexTri has a transmitting coil composed of three hexagonal coils connected in series. The triangular arrangement of the three hexagonal coils itself has natural anti-offset characteristics. The central triangular region achieves position tolerance through magnetic field superposition. When there is a certain degree of offset between the receiving coil and the transmitting coil, the magnetic induction intensity between the transmitting coil and the receiving coil of the system will fluctuate, but the overall system still has good performance. Therefore, the inherent characteristics of this structure determine that this coil has a better ability than traditional coils in maintaining a constant coupling coefficient and stable transmission efficiency.

[0038] like Figures 2-4As shown in Figure S1.2, the magnetic induction intensity distribution cloud maps of tightly wound and loosely wound coils were obtained using finite element simulation software. Further analysis was conducted to select the winding method, as the coil winding method directly affects the magnetic field distribution, mutual inductance coupling, losses, and manufacturing feasibility. To compare and analyze the influence of the winding method on the magnetic induction intensity of the coil, the magnetic induction distribution cloud maps show that the magnetic induction intensity is strong on the outer side of the tightly wound coil and decreases in the central region; the magnetic induction intensity is weak on the outer side of the loosely wound coil and strong in the central region. The combined coil can fully utilize the advantages of tightly wound and loosely wound coils. S1.3, finite element simulation software was used to obtain magnetic induction intensity distribution cloud maps for different coil numbers. Further analysis was conducted to select the winding method. The combined coil consists of a single loosely wound coil and a single tightly wound coil, as shown in the schematic diagram below. Figure 5 As shown in the diagram, the three-coil combined winding structure has a loose outer layer, a tight middle layer, and a loose inner layer. Figure 6 As shown, the number of coil turns is set to 3, 3, 3 in sequence, and the other parameters are set as shown in the table below:

[0039] The magnetic induction distribution cloud diagram of the three-coil winding is as follows: Figure 7 As shown in the image, the three-coil design has a better induction intensity distribution compared to the two-coil design. Considering practical applications, the number of coils is positively correlated with the coil design complexity. Too many coils will increase the design difficulty and cost. Therefore, the LTL-HexTri coil with 3 coils was selected for research.

[0040] Preferably, the anti-offset coil is a hexagonal coil, and the loose-tight triangular hexagonal coil LTL-HexTri is designed by combining hexagonal coils.

[0041] Preferably, S2 includes: Figure 8 As shown in S2.1, the outer, inner, and middle coils of the LTL-HexTri coil are simplified into a coupling mechanism diagram; S2.2, Calculation parameters, including the magnetic induction intensity and magnetic flux generated by the outer, middle and inner coils of the single hexagonal coil at the transmitting end in the Z-axis direction, the mutual inductance of the combined coils at the transmitting end, and the total self-inductance at the transmitting end.

[0042] Preferably, step S2.2 calculates the magnetic induction intensity generated by the outer, middle, and inner coils of a single hexagonal coil in the Z-axis direction. According to Biot's law, for a finite-length straight conductor, the magnitude of the magnetic induction intensity generated at any point is: (1); In the formula: D is the vertical distance from the conductor to the magnetic field calculation point, and θ is the angle between the conductor and the position vector of any point; ρ is the permeability of free space; I is the current flowing through the wire; Preferably, only the single hexagonal coil at the transmitting end is analyzed, and the external coil wire is selected. Middle coil internal coil Assuming Coordinates are ,but Coordinates are ; Coordinates are , Coordinates are ; Coordinates are , Coordinates are ; Combine any point Substituting into the formula, we can see that: The magnitude of the magnetic induction intensity generated at point P , The magnitude of the magnetic induction intensity generated at point P , The magnitude of the magnetic induction intensity generated at point P : (2); (3); (4).

[0043] Further calculation of the conductor , , A magnetic field strength is generated in the z-direction at point P. , , : (5); (6); (7); Therefore, the magnetic induction intensities generated by the outer, middle, and inner coils in the Z-axis direction are respectively , , As shown in the following formula: (8); (9); (10); In the formula: , , , , , These represent the magnetic induction intensity generated by each side of the outer hexagonal coil in the Z-axis direction; , , , , , These represent the magnetic induction intensity generated by each side of the central hexagonal coil in the Z-axis direction; , , , , , These represent the magnetic induction intensity generated by each side of the internal hexagonal coil in the Z-axis direction.

[0044] Preferably, step S2.2 calculates the magnetic flux generated in the outer, middle, and inner coils of the single hexagonal coil along the Z-axis and the mutual inductance of the combined coils, dividing the receiving coil into four regions and labeling the coils with the outer diameters of the hexagonal coils as follows: , , The inner diameters of the hexagonal coils are as follows: , , , The side length of the outer hexagon , The side length of the central hexagon , The side length of the inner hexagon , , , These are the specific numerical values ​​for the number of turns on the outer, middle, and inner sides of the coil, respectively. The diameter of the wire. The external coil turn spacing, The pitch is the internal coil turn spacing, and j, g, and k represent the number of turns of the corresponding coil, respectively; The magnetic flux generated by the outer coil of the transmitting coil in various parts of the receiving coil is calculated using the following formula: (11); (12); (13); In the formula: , , The magnetic flux generated by the outer coil of the transmitting coil on the outer, middle, and inner coils of the receiving coil, respectively; , , , For the boundary function of the external coil; , , , The boundary function of the middle coil; , , , For the boundary function of the internal coil; The magnetic flux density generated by the external coil of the transmitting coil; The magnetic flux generated by the central coil of the transmitting coil in various parts of the receiving coil is shown in the following formula: (14); (15); (16); In the formula: , , The magnetic flux generated by the middle coil of the transmitting coil to the outer, middle, and inner coils of the receiving coil, respectively; The magnetic flux generated by the internal coil of the transmitting coil in various parts of the receiving coil is shown in the following formula: (17); (18); (19); In the formula: , , The magnetic flux generated by the internal coil of the transmitting coil to the external, middle, and internal coils of the receiving coil, respectively; Based on the above analysis, the formula for mutual inductance can be obtained as follows: (20); In the formula: This is the total mutual inductance between the transmitting and receiving coils; , , These are the specific numerical values ​​for the number of turns on the outside, middle, and inside of the coil, respectively. , , The magnetic flux generated by the outer coil of the transmitting coil on the outer, middle, and inner coils of the receiving coil, respectively; , , The magnetic flux generated by the middle coil of the transmitting coil to the outer, middle, and inner coils of the receiving coil, respectively; , , The magnetic flux generated by the internal coil of the transmitting coil to the external, middle, and internal coils of the receiving coil, respectively; This is the current flowing through the transmitting coil.

[0045] Preferably, in S2.2, the total self-inductance L1 of the entire transmitting end is the sum of the self-inductances of the three coils plus their mutual inductance. For a single hexagonal LTL coil, its self-inductance is: (twenty one); In the formula: The self-inductance of an LTL coil of any individual hexagon; For the mutual inductance between the internal and central coils of a single hexagon; For the mutual inductance between the internal and external coils of a single hexagonal coil; The mutual inductance between the middle and outer coils of a single hexagonal coil; The self-inductance of the external coil; The self-inductance of the middle coil; The internal coil's self-inductance; If three coils are connected in series and driven in phase, the total self-inductance at the transmitter is: (twenty two); In the formula: The total self-inductance of the transmitting coil; For the self-inductance of an arbitrary individual hexagonal LTL coil, It is the mutual inductance between coil A and coil B; It is the mutual inductance between coil A and coil C; It is the mutual inductance between coil B and coil C; It is the total mutual inductance between any two transmitting coils, that is, the coupling between their respective outer loop, middle loop, and inner loop; The self-inductance of coil A; The self-inductance of coil B; The self-inductance of coil C; Formula for the self-inductance of a hexagonal coil: (twenty three); In the formula: L represents the self-inductance of the hexagonal coil, Permeability of free space; This refers to the number of coil turns. The average diameter of the coil; The fill factor; , , , These are coefficients specific to hexagons, and all are constants; This is a shape scaling factor, which is related to the integral of the total number of turns and the average diameter of the coil; For logarithmic geometric corrections, the cross-geometric mean distance between turns is correlated; The coefficient of the linear term is usually ignored because the hexagon has symmetry, which causes the linear terms to cancel each other out. For edge correction of quadratic terms; The formula for average diameter is: (twenty four); The formula for the fill factor is: (25); In the formula: The inner diameter of the coil; This is the outer diameter of the coil.

[0046] Preferably, S3 includes: S3.1, selecting an SS-type compensation topology, where the coils at both the transmitting and receiving ends are connected in series with a capacitor. By adjusting the capacitor parameters, the system can operate at a specific resonant frequency, achieving efficient energy transfer. The SS topology has a relatively simple structure, is easy to implement and control, and can maintain a relatively stable output voltage when the load changes. The equivalent circuit model is as follows: Figure 10 As shown, R1 and R2 are the internal resistances of each coil, L1 and L2 are the inductances of each coil, and C1 and C2 are the resonant capacitors matched to each coil.

[0047] S3.2, as Figure 11 As shown in the table below, a simulation model is built, and the simulation model parameters are as follows:

[0048] S3.3, Compare and analyze the change of coupling coefficient k of the coupling mechanism with transmission distance before and after optimization. The optimization results are as follows: Figure 12 As shown, when the coils are in a directly facing state and the transmission distance varies within the range of 2–16 cm, the following occurs: Figure 12 It can be seen that the coupling coefficient was significantly improved after coil optimization. Specifically, when the transmission distance was 2cm and 16cm, the coupling coefficient was improved by 23.8% and 18.5% respectively after coil optimization.

[0049] Preferably, the changes in output power and efficiency when the system receiver is offset longitudinally and laterally are as follows: Figure 13 , 14As shown in the figure, the positive and negative signs of the vertical offset represent the distance the receiving coil is offset along the positive and negative half-axis of the Y-axis, and the positive and negative signs of the horizontal offset represent the distance the receiving coil is offset along the positive and negative half-axis of the X-axis. It can be seen that when the receiving end is offset vertically, the output power decreases as the offset distance increases, and the system efficiency also decreases as the offset distance increases. When the receiving end is offset laterally along the positive half-axis, both the output power and transmission efficiency show a trend of first increasing and then decreasing. When the receiving end is offset laterally along the negative half-axis, the output power decreases as the offset distance increases, and the efficiency first decreases, then increases, and then decreases again. The coil structure is symmetrical about the X-axis but asymmetrical about the Y-axis, so the output performance changes differently when the receiving coil is offset in different directions. The proposed coupling mechanism can generate a uniform magnetic field in the charging region above the transmitting end, significantly enhancing the anti-offset capability. Within a horizontal offset range of ±80mm and a vertical offset range of ±40mm, the system can maintain an output power of 300W and an efficiency of not less than 80%.

[0050] Preferably, the S3.2 simulation model includes a high-frequency inverter, a transmitting coil, a receiving coil, and a compensation capacitor. The high-frequency inverter is typically composed of four MOSFETs, which convert the DC input voltage into a high-frequency AC voltage, drive the transmitting coil to generate a high-frequency magnetic field, and the receiving coil senses the magnetic field generated by the transmitting coil to generate an induced electromotive force. After rectification and filtering, the induced electromotive force provides DC power to the load.

Claims

1. A method of designing an anti-skew coil, characterized by: It comprises the following steps: S1, LTL-HexTri coil structure design; S2, LTL-HexTri coil parameter modeling; S3, select the ss compensation topology, build the ss type wireless power transmission system for simulation verification.

2. The method of designing an anti-slip coil according to claim 1, characterized in that: The S1 comprises: S1.1, determining the research object; S1.2, using finite element simulation software to simulate to obtain the magnetic induction intensity distribution cloud of the tightly wound coil and the loosely wound coil, and further analyze and select the winding method; S1.3, using finite element simulation software to simulate to obtain the magnetic induction intensity distribution cloud of the coil wound in different numbers, and further analyze and select the winding method.

3. A resistive coil as claimed in claim 1, characterised in that: The anti-offset coil is a hexagonal coil as the research object, and a loose triangle hexagonal coil LTL-HexTri is designed by combining the hexagonal coil.

4. The method of designing an anti-slip coil according to claim 1, wherein: The S2 comprises: S2.1, simplifying the external, internal and middle coils of the LTL-HexTri coil into a coupling mechanism diagram; S2.2, calculating parameters, including the magnetic induction intensity and magnetic flux generated by the external, middle and internal coils of the single hexagonal coil of the transmitting end in the Z-axis direction, the mutual inductance of the combined coil of the transmitting end, and the total self-inductance of the transmitting end.

5. A method of designing an anti-skew coil as claimed in claim 4, characterized in that: The S2.2 calculates the magnetic induction intensity generated by the external, middle and internal coils of the single hexagonal coil in the Z-axis direction, according to the Biot-Savart law, for a finite length straight wire, the magnetic induction intensity generated at any point is: （1）； where D is the perpendicular distance from the wire to the point of calculation of the field, and θ is the angle between the wire and the position vector of the arbitrary point. is the vacuum permeability. I is the current flowing through the wire; Only the single hexagon coil of the transmitting end is analyzed, and the outer coil wire , the middle coil , and the inner coil are selected Assume that the coordinates of , the outer coil wire are ; the coordinates of the middle coil wire are , the coordinates of the inner coil wire are ; the coordinates of the inner coil wire are , the coordinates of the inner coil wire are ; Combining any point , the formula calculation can be known: The magnetic induction intensity generated at P point , The magnetic induction intensity generated at P point , The magnetic induction intensity generated at P point , The magnetic induction intensity generated at P point , The magnetic induction intensity generated at P point : （2）； （3）； （4）。 6. A method of designing an anti-skew coil as claimed in claim 5, characterized in that: Further calculating the wire , , Forming the magnetic induction in the z direction at point P , , : （5）； （6）； （7）； Therefore, the magnetic induction intensity generated by the outer, middle and inner coils in the Z-axis direction is respectively , , The following formula: （8）； （9）； （10）； In the formula: , , , , , are the magnetic induction intensity generated by each side of the outer hexagonal coil in the Z-axis direction, respectively; , , , , , are the magnetic induction intensity generated by each side of the middle hexagonal coil in the Z-axis direction, respectively; , , , , , are the magnetic induction intensity generated by each side of the inner hexagonal coil in the Z-axis direction, respectively.

7. A method of designing an anti-skew coil as claimed in claim 6, characterized in that: The S2.2 calculates the mutual inductance of the outer, middle and inner coils of a single hexagonal coil in the Z-axis direction and the mutual inductance of the combined coils, divides the receiving coil into four areas, and labels the hexagonal coil as follows: the outer diameter of the hexagonal coil is , , , the inner diameter of the hexagonal coil is , , , is the outer hexagonal side length , is the middle hexagonal side length , is the inner hexagonal side length , , , are the specific values of the turns of the outer, middle and inner coils, respectively, and is the wire diameter, is the turn spacing of the outer coil, is the turn spacing of the inner coil, and j, g and k represent the number of turns of the corresponding coil, respectively. The magnetic flux generated by the external coil of the transmitting coil in each part of the receiving coil is as follows: （11）； （12）； （13）； wherein: , , Bext is the magnetic flux generated by the transmit coil outer coil to the receive coil outer, middle, inner coils, respectively; , , , Bext is the boundary function of the outer coil; , , , Bmid is the boundary function of the middle coil; , , , Bint is the boundary function of the inner coil; Bext is the magnetic induction generated by the transmit coil outer coil. The magnetic flux generated by the middle coil of the transmitting coil in each part of the receiving coil is as follows: （14）； （15）； （16）； In the formula: , , is the magnetic flux generated by the outer, middle and inner coils of the receiving coil, respectively, to the middle coil of the transmitting coil. The magnetic flux generated by the internal coil of the transmitting coil in each part of the receiving coil is as follows: （17）； （18）； （19）； In the formula: , , is the magnetic flux generated by the inner coil of the transmitting coil to the outer, middle, and inner coils of the receiving coil, respectively; Combining the above analysis, the mutual inductance formula is: （20）； In the formula: is the total mutual inductance between the transmitting coil and the receiving coil; , , are the specific number of turns of the outer, middle, and inner coils, respectively; , , are the magnetic fluxes generated by the outer coil of the transmitting coil to the outer, middle, and inner coils of the receiving coil, respectively; , , are the magnetic fluxes generated by the middle coil of the transmitting coil to the outer, middle, and inner coils of the receiving coil, respectively; , , are the magnetic fluxes generated by the inner coil of the transmitting coil to the outer, middle, and inner coils of the receiving coil, respectively; is the current flowing through the transmitting coil.

8. A method of designing an anti-aliasing coil according to claim 7, characterized in that: In the S2.2, the total self-inductance L1 of the entire transmitting end is the sum of the self-inductances of the three coils plus the mutual inductance between them, for a single hexagonal LTL coil, the self-inductance is: （21）； wherein: LTLcoilselfis the self-inductance of the arbitrary individual hexagonal LTL coil; LTLcoilinteris the mutual inductance between the inner and middle coils of the arbitrary individual hexagonal LTL coil; LTLcoilouteris the mutual inductance between the inner and outer coils of the arbitrary individual hexagonal LTL coil; LTLcoilmiddleis the mutual inductance between the middle and outer coils of the arbitrary individual hexagonal LTL coil; LTLcoiletselfis the self-inductance of the outer coil; LTLcoilmiddleis the self-inductance of the middle coil; LTLcoilinneris the self-inductance of the inner coil; The three coils are connected in series and driven in phase, so the total self-inductance of the transmitting end is: （22）； wherein: is the total self-inductance of the transmit coil; is the self-inductance of any individual hexagonal LTL coil, is the mutual inductance between coil A and coil B; is the mutual inductance between coil A and coil C; is the mutual inductance between coil B and coil C; is the total mutual inductance between any two transmit coils, i.e. the coupling between their respective outer, middle, and inner rings; is the self-inductance of coil A; is the self-inductance of coil B; is the self-inductance of coil C; The self-inductance formula of the hexagonal coil is: （23）； where L represents the self-inductance of a hexagonal coil, is the vacuum permeability; is the number of turns of the coil; is the average diameter of the coil; is the fill factor; , , , is the hexagonal specific coefficient, which is a constant; is the shape scaling factor, which is related to the integral of the product of the total number of turns and the average diameter of the coil; is the logarithmic term geometric correction, which is related to the mutual geometric mean distance between turns; is the linear term coefficient, which is usually ignored because the hexagon has symmetry so that the linear term cancels out; is the quadratic term edge correction; The average diameter formula is: （24）； The filling factor formula is: （25）； In the formulae: is the inner diameter of the coil; is the outer diameter of the coil.

9. The method of designing an anti-slip coil according to claim 1, wherein: The S3 comprises: S3.1, selecting the SS compensation topology, the coils of the transmitting end and the receiving end are connected in series with the capacitor, by adjusting the parameters of the capacitor, the system can work at a specific resonant frequency, realizing effective energy transmission; S3.2, building a simulation model; S3.3, comparing and analyzing the change of the coupling coefficient k of the coupling mechanism before and after optimization with the transmission distance.

10. A method of designing an anti-aliasing coil according to claim 9, characterized in that: The S3.2 simulation model comprises a high-frequency inverter, a transmitting coil, a receiving coil and a compensation capacitor.

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