High-offset-tolerance unmanned aerial vehicle wireless charging coupling mechanism and optimization method

Abstract

The application relates to a high-offset-tolerance unmanned aerial vehicle wireless charging coupling mechanism and an optimization method, and belongs to the technical field of high-offset-tolerance unmanned aerial vehicle wireless charging. The mechanism comprises a compensation coil and a composite circular coil, the compensation coil and the composite circular coil are connected in series to form a single-current loop, the composite circular coil comprises a large circular coil and a small circular coil, and the large circular coil and the small circular coil are connected in series in the same direction. Through the mutual complementation mechanism of the magnetic flux change increase and decrease of the strong magnetic field characteristics of the edge of the compensation coil and the strong magnetic field characteristics of the center of the double circular coil, the mutual inductance fluctuation rate is less than or equal to 5% under the offset working condition of the receiving end, the traditional scheme is greater than or equal to 25%, the effective offset tolerance is increased to 35% of the diameter of the transmitting end, that is, 140mm / Phi400mm, which is 2.1 times larger than the traditional single-polarity structure; the structure breaks through the magnetic field distribution limitation of "strong center and weak edge", and solves the power stability fluctuation problem caused by horizontal offset.

Description

Technical Field

[0001] This invention relates to a wireless charging coupling mechanism and optimization method, belonging to the field of wireless charging technology for unmanned aerial vehicles with high offset tolerance. Background Technology

[0002] In UAV wireless charging systems, the transmitter needs to balance economic efficiency and functionality, employing a single circular coil configuration to achieve low-cost deployment, easy control, and multi-load compatibility. The receiver, constrained by compact installation space and lightweight design, prioritizes a miniaturized circular receiving coil to maximize space utilization while maintaining a transmission distance of approximately 1cm. This design can maintain a basic transmission efficiency of over 85% in low-to-medium power scenarios (100-2000W). While this traditional circular coupler architecture meets lightweight requirements, its inherent symmetrical magnetic field distribution limits its horizontal offset resistance.

[0003] Horizontal offset conditions pose systemic risks: When the relative displacement between the transmitter and receiver coils exceeds 20% of the transmitter coil diameter, the "strong center, weak edge" magnetic field gradient of the circular coil causes a nonlinear decay in the coupling coefficient, typically with a decrease of 40%-60%. This induces DC link voltage oscillations and severe output power fluctuations with an amplitude of ≥±25%. Experiments show that when the offset reaches 20% of the coil radius, the system efficiency decays to a critical value of <70%, highlighting the core significance of offset suppression for charging safety.

[0004] To suppress output power fluctuations in wireless charging systems caused by receiver offset, research has made significant progress in several areas, including coupling mechanism optimization, control strategy design, and power topology innovation. In the field of coupling mechanism optimization, for traditional unipolar coils, strategies such as increasing the relative size of the transmitting and receiving coils, optimizing coil spacing, and improving core structure design can improve the system's anti-offset capability to a limited extent. However, these improvement strategies typically cannot match the combined improvement in space utilization efficiency and offset tolerance performance compared to multipolar coil architectures with the same size constraints.

[0005] Therefore, there is an urgent need to propose a high offset tolerance-resistant wireless charging coupling mechanism for UAVs and an optimization method to solve the above-mentioned technical problems. Summary of the Invention

[0006] To address the aforementioned problems, a high offset tolerance wireless charging coupling mechanism and optimization method for unmanned aerial vehicles (UAVs) are provided. A brief overview of the invention is given below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0007] The technical solution of this invention:

[0008] A high offset tolerance wireless charging coupling mechanism for unmanned aerial vehicles includes a compensation coil and a composite circular coil. The compensation coil and the composite circular coil are connected in series to form a single current loop. The composite circular coil includes a large circular coil and a small circular coil, which are connected in series in the same direction.

[0009] Preferably, the compensation coil has a central through hole in the middle, the compensation coil has a slit, and the compensation coil has a C-shaped through hole.

[0010] Preferably, the compensation coil and the composite circular coil at the transmitting end adopt a vertically stacked series coil structure;

[0011] The large and small circular coils are arranged coaxially and in the same plane, with the inner diameter of the large circular coil being larger than the outer diameter of the small circular coil.

[0012] The outer diameter of the compensation coil is aligned with the outer edge of the composite circular coil, and the inner diameter of the U-shaped coil is 67.5% ± 5% of the outer diameter.

[0013] Preferably, the receiver uses a discrete strip ferrite array with a strip ferrite thickness of 1mm ± 0.2mm.

[0014] Preferably, the transmitter adopts a three-layer vertical stacked structure: a circular ferrite substrate, a composite circular coil, and a compensation coil are arranged coaxially from bottom to top.

[0015] An optimization method for a high offset tolerance unmanned aerial vehicle (UAV) wireless charging coupling includes the following steps:

[0016] By adjusting the arm spacing to control the edge magnetic field gradient, the turns ratio of the composite circular coil is optimized to control the central magnetic field strength, ensuring that the total mutual inductance-offset curve satisfies the following: within the target offset tolerance Δ y Minimize mutual inductance volatility Δ M , or given Δ M Maximize Δ under threshold y .

[0017] Preferred: By combining scanning parameters through finite element simulation, solutions that simultaneously satisfy the following condition are selected: maximum offset distance. y max ≥ y allow Mutual inductance amplitude balance 0.9 M CR ≤ 2 M UR|max ≤ 1.1 M CR Peak position synchronization 0.9 y | M UR|max≤ 2 y | M CR|max ≤ 1.1 y | M UR|max .

[0018] The present invention has the following beneficial effects:

[0019] 1. This invention achieves a mutual inductance fluctuation rate of ≤5% under receiver offset conditions by a complementary mechanism of flux variation between the strong magnetic field characteristics at the edge of the compensation coil and the strong magnetic field characteristics at the center of the double circular coil, compared to ≥25% in traditional schemes. This increases the effective offset tolerance to 35% of the transmitter diameter (140mm / Φ400mm), which is 2.1 times larger than the traditional unipolar structure. This structure breaks through the limitation of "strong center and weak edge" magnetic field distribution and solves the problem of power stability fluctuation caused by horizontal offset.

[0020] 2. This invention, through a unique coil topology, enables the inductive sensor to simultaneously achieve high stable output and high installation robustness in the target measurement direction. This design makes the sensor's mutual inductance characteristics highly insensitive in the direction perpendicular to the measurement plane, typically the Z-axis. This characteristic directly translates into a significant application advantage—the sensor has a very high tolerance for vertical installation position deviations of the measured object, significantly reducing the stringent requirements for installation gap accuracy. This comprehensive technical effect not only simplifies the installation and debugging process, reducing assembly costs and time, but also ensures the stable operation of the sensor in complex multi-degree-of-freedom motion environments or scenarios with mechanical vibration, greatly expanding its application potential in demanding scenarios such as high-precision industrial automation inspection, robot joint sensing, and vibration platform displacement monitoring.

[0021] 3. This invention establishes a coil parameter-anti-offset performance design process: by compensating for the coil arm spacing to control the edge magnetic field gradient, the turns ratio of the circular coil is optimized. N LTL / N LTS By adjusting the central magnetic field strength, the shape of the total mutual inductance-offset curve can be precisely designed; this process can achieve a specific offset tolerance ∆. y Minimum mutual inductance volatility ∆ M , or given ∆ M Maximize ∆ at threshold y This meets the compatibility requirements of high-precision wireless charging systems for spatial adaptability and power stability. Attached Figure Description

[0022] Figure 1 This is a top view of a high offset tolerance wireless charging coupling mechanism for drones.

[0023] Figure 2 This is a side view of a high offset tolerance wireless charging coupling mechanism for drones.

[0024] Figure 3 This is a three-dimensional view of a wireless charging coupling mechanism for a drone with high offset tolerance.

[0025] Figure 4 This is a schematic diagram of a wireless power transfer circuit based on a high offset tolerance coupling mechanism.

[0026] Figure 5 It is the curve showing the change in mutual inductance of the U-shaped coil as the horizontal offset distance increases.

[0027] Figure 6 This is a top view of an example of a U-shaped coil coupling mechanism.

[0028] Figure 7 This is a right view of an example of a U-shaped coil coupling mechanism.

[0029] Figure 8 It is a graph showing the change in mutual inductance of the receiving coil as the horizontal offset distance increases.

[0030] Figure 9 This is a top view of an example of a high-level offset tolerance coupling mechanism.

[0031] Figure 10 This is a schematic diagram of the dimensions of a high-level offset tolerance coupling mechanism, shown on the right.

[0032] Figure 11 This is the curve showing the change in mutual inductance of the coil as the horizontal offset distance increases:

[0033] (a) Individual graph of mutual inductance; (b) Combined graph of mutual inductance.

[0034] Figure 12 This is a top view of an example of a high-level offset tolerance coupling mechanism.

[0035] Figure 13 This is a schematic diagram of the dimensions of a high-level offset tolerance coupling mechanism, shown on the right.

[0036] Figure 14 It is a graph showing the change in mutual inductance of the coil at different vertical distances as the horizontal offset distance increases.

[0037] Figure 15 It is a graph showing the change in self-inductance of the receiver and transmitter as the horizontal offset distance increases.

[0038] Figure 16 Here is the output voltage and current waveform diagram during offset:

[0039] (a)0mm; (b)40mm; (c)80mm; (d)120mm; (e)140mm.

[0040] In the diagram: 1-compensation coil, 2-large circular coil, 3-small circular coil, 4-receiving end, 5-arm spacing, 6-C-type through hole, 7-circular ferrite substrate. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0042] Specific implementation method one: Combining Figure 1-16 This embodiment describes a high offset tolerance wireless charging coupling mechanism for unmanned aerial vehicles, including a compensation coil Tx. U and composite circular coil (Tx) L +Tx S The compensating coil and the composite circular coil are connected in series to form a single current loop, and their magnetic field is in phase with that of the composite circular coil; the composite circular coil includes a large circular coil Tx. L and small circular coil Tx S Large circular coil Tx L With small circular coil Tx S Series connection in the same direction, power supply and compensation coil Tx U Large circular coil Tx L Small circular coil Tx S The three coils are connected in a sequential loop, with the same phase winding, the same direction of current, and the same phase of magnetic field.

[0043] Specific Implementation Method Two: Combining Figure 1-16 This embodiment describes a high offset tolerance wireless charging coupling mechanism for unmanned aerial vehicles, including a compensation coil Tx. U It is a circular, U-shaped coil with a central through-hole coaxial with the circular U-shaped coil. The diameter of the central through-hole is the same as that of the compensation coil Tx. U The inner diameter of the compensation coil Tx U It has a radially penetrating slit as the arm spacing, and the compensation coil Tx U It has a C-shaped through hole, which is coaxially arranged with the central through hole. The edge of the C-shaped through hole is connected to the corresponding compensation coil Tx. U The outer edge distances can be the same, and the C-shaped through holes can be set symmetrically with the gap as the center;

[0044] Optimization of complementary coils based on traditional magnetic field distribution: Based on the traditional dual-circular transmitting coil and single receiving coil structure (whose inherent magnetic field distribution is strong at the center and weak at the edges), a U-shaped transmitting coil with strong edges and weak center is introduced. This improved structure uses the dual-circular transmitting coil and U-shaped transmitting coil in series, taking advantage of the complementary magnetic field distribution. When the receiving coil is deflected, the magnetic flux changes of the circular transmitting coil and the U-shaped transmitting coil coupled to the receiving coil show opposite trends (increase and decrease are complementary), thereby effectively offsetting part of the deflection effect and significantly improving the anti-deflection stability of the total coupling mutual inductance.

[0045] Specific implementation method three: Combining Figure 1-16 This embodiment describes a high offset tolerance wireless charging coupling mechanism for unmanned aerial vehicles (UAVs), including a compensation coil Tx at the transmitting end. U The composite circular coil adopts a vertically stacked series coil structure. The composite circular coil can be attached to or not attached to the compensation coil as the transmitting end. When attached, it can reduce magnetic field leakage, improve utilization and meet the requirements of magnetic field uniformity, and is coaxial with the compensation coil.

[0046] Large circular coil Tx of uniform thickness L Small circular coil Tx S Coaxial and coplanar setup, large circular coil Tx L The inner diameter is larger than the small circular coil Tx S Outer diameter;

[0047] Compensation coil Tx U outer diameter D LTS_out Aligned with the outer edge of the composite circular coil, the inner diameter of the U-shaped coil D LU_inner It is 67.5% ± 5% of the outer diameter; that is, the compensation coil Tx U Outer diameter and large circular coil Tx L The outer diameters are the same, and the compensation coil Tx U The inner diameter of the C-type through hole and the small circular coil Tx S The outer diameters are the same, and the compensation coil Tx U The outer diameter of the C-type through hole is larger than that of the large circular coil Tx. L The inner diameter of the compensation coil Tx U The inner diameter is larger than the compensation coil Tx U The inner diameter.

[0048] Specific implementation method four: Combination Figure 1-16This embodiment describes a high offset tolerance wireless charging coupling mechanism for unmanned aerial vehicles. The receiving end employs a circular array of discrete elongated ferrite strips to enhance magnetic field capture efficiency through magnetic flux convergence. The thickness of the rectangular elongated ferrite strips is 1mm ± 0.2mm. The U-shaped coil compensates for the strong central magnetic field and weak edge characteristic of the composite circular coil by having a strong edge magnetic field and a weak center magnetic field. This ensures that the mutual inductance fluctuation rate of the receiving coil is ≤5% when horizontally offset, and the offset tolerance reaches 35% of the transmitter diameter.

[0049] Specific Implementation Method Five: Combining Figure 1-16 This embodiment describes a high offset tolerance wireless charging coupling mechanism for unmanned aerial vehicles (UAVs). The transmitter employs a three-layer vertically stacked architecture: a circular ferrite substrate, a composite circular coil, and a compensation coil Tx. U The components are arranged coaxially from bottom to top; the circular ferrite substrate and the composite circular coil can be attached together, and the receiving end can be located coaxially above the composite circular coil.

[0050] Specific Implementation Method Six: Combination Figure 1-16 This embodiment describes an optimized method for a high-offset-tolerance wireless charging coupling mechanism for unmanned aerial vehicles (UAVs). Based on specific embodiments one through five, the transmitting end employs a combination structure of vertically stacked and wound circular coils and U-shaped compensating coils. The inherent magnetic field distribution of the circular coil (high magnetic flux density in the central region and low magnetic flux density at the edges) is effectively canceled by the compensating magnetic field generated by the U-shaped coil, which has the opposite characteristic of low magnetic flux density in the center and high magnetic flux density at both ends (weak in the middle and strong at both ends). This achieves a highly uniform spatial synthetic magnetic field at the transmitting end. The core advantage of this uniform magnetic field is that when the receiving coil is within its design limits... When moving within the lateral offset range, the effective vertical magnetic flux component of the coupled link remains relatively stable, thereby significantly improving the mutual inductance constancy of the system and greatly reducing transmission performance fluctuations, ultimately achieving excellent anti-offset tolerance characteristics. In addition, this invention provides key structural parameter degrees of freedom to precisely control performance indicators: by optimizing the distance between the two parallel arms of the U-shaped coil and its number of turns, the overall distribution of the synthetic magnetic field can be systematically adjusted, thereby changing the trend of total mutual inductance with the offset distance of the receiver. This flexibility allows this design to be customized and optimized based on the specific requirements of the target application (such as the required offset tolerance range and the allowable mutual inductance fluctuation rate) to meet the diverse needs of highly robust wireless charging systems.

[0051] The method includes the following steps:

[0052] By adjusting the spacing between the U-shaped coil arms to control the edge magnetic field gradient, the turns ratio of the composite circular coil is optimized. N LTL / N LTS The number of turns of the large circular coil / the number of turns of the small circular coil are used to adjust the central magnetic field strength so that the total mutual inductance-offset curve satisfies the following: within the target offset tolerance Δ y Minimize mutual inductance volatility Δ M , or given Δ M Maximize Δ under threshold y ;

[0053] Parametric design for offset tolerance and fluctuation control: To meet the differentiated requirements of offset tolerance (maximum allowable offset range) and mutual inductance stability (fluctuation amplitude) for different application scenarios, a set of key parameter design processes is proposed. By optimizing key structural parameters such as the arm spacing of the U-shaped coil and the number of turns of the circular coil, the variation characteristics of the "total mutual inductance-anti-offset" curve can be systematically adjusted. This strategy can design coupling mechanism parameters for a given maximum allowable offset range target to minimize or optimize the mutual inductance fluctuation amplitude within that offset range.

[0054] Specific implementation method seven: Combination Figure 1-16 This embodiment describes an optimization method for a high offset tolerance unmanned aerial vehicle (UAV) wireless charging coupling mechanism, which is achieved through finite element simulation scanning parameter combinations (…). N LR , N LU ), N LR Number of turns at the transmitter N LU To compensate for the number of coil turns, solutions that simultaneously meet the following conditions are selected: maximum offset distance. y max ≥ y allow Mutual inductance amplitude balance 0.9 M CR ≤ 2 M UR|max ≤ 1.1 M CR Peak position synchronization 0.9 y | M UR|max ≤ 2 y | M CR|max ≤ 1.1 y | M UR|max ; y allow To allow for offset distance, MCR As a reference mutual inductance, M UR|max This represents the maximum value of the actual mutual inductance. y This is the offset position;

[0055] The changes in the coil magnetic field cancel each other out through the series coupling path, significantly suppressing the fluctuation of the coil system's self-inductance. Within the ±140mm full offset tolerance range, the fluctuation amplitude of the receiver coil's self-inductance is constrained to within ±0.3μH, with a relative change rate ≤2%. The fluctuation amplitude of the transmitter coil's self-inductance is constrained to within ±12μH, with a relative change rate ≤2.7%. The low relative change rate of the coupler's self-inductance makes the output voltage stable when the system is in an offset state, reducing the output voltage ripple.

[0056] Example 1:

[0057] The transmitter employs a three-layer vertical stacked architecture: based on a circular ferrite substrate, a large circular coil (Tx... L ) and small circular coil (Tx S A counter-clockwise current in the same direction is passed through it, generating a +Z-direction main magnetic field that is strong at the center and weak at the edges; a U-shaped compensation coil (Tx) is integrated on it. U The outer arm generates a +Z magnetic field through counterclockwise current, while the inner bent portion generates a -Z magnetic field through clockwise current, synthesizing a complementary gradient field with enhanced edges. Through electromagnetic coupling design, the strong magnetic field at the center of the circular coil and the strong magnetic field at the edge of the U-shaped coil are superimposed, forming an effective uniform region on the receiving plane. The receiving end consists of a circular coil (Rx) and a discrete strip ferrite array; the latter enhances the spatial magnetic field capture efficiency through magnetic flux convergence. Under offset conditions, the flux changes from the two excitation sources complementarily cancel each other out, reducing mutual inductance fluctuations and significantly improving the system's robustness against offset.

[0058] The transmission distance is defined as D, and the receiving end circular coil is defined as L. R The transmitter employs a vertically stacked series topology—a large circular coil L. TL With small circular coil L TS First, connect them in series to form a composite coil L C (L) TL With L TS The spatial distribution of the magnetic field is in phase, satisfying L C ≈L TL + L TS ), L C Then with U-shaped coil L U Directly connected in series to form a single current loop; under this architecture, L R The independent mutual inductance between each transmitting unit is: with L U M RU 、and L TL MRTL 、and L TS M RTS Composite coil L C For L R The total mutual inductance is determined by the series superposition property: M RC = M RTL + M RTS L C With L U The magnetic field spatial distribution is in phase (ensuring this through the vertical stacking structure), L R The equivalent system mutual inductance of the entire series-connected transmitting circuit can be approximated as Meq≈M RC + M RU .

[0059] The design steps for the coupling mechanism are as follows:

[0060] (1) Definition of basic system parameters

[0061] During the initial design phase, the key electrical specifications of the static wireless charging system need to be clearly defined: rated power. P rated Operating frequency f op Input / output voltage V in / V out and corresponding current I in / I out This provides boundary conditions for subsequent coil design.

[0062] (2) Geometric constraints and coil parameter solidification

[0063] The maximum containment size of the transmitter is determined based on the spacing of the drone's landing gear, and the structural parameters of the transmitter coil assembly are fixed: large circular coil (outer diameter) D LTL out Number of turns N LTL Small round coil (outer diameter) D LTS_out Number of turns N LTS ), U-shaped coil (outer diameter) D LU_out , inner diameter D LU_inner Number of turns N LU ); Deriving the outer diameter of the receiving coil based on electromagnetic compatibility criteria D LR_out and number of turns N LR The conductor specifications are optimized based on current density and skin depth.

[0064] (3) Minimum performance verification

[0065] Using finite element simulation tools (such as ANSYS Maxwell) to scan parameter combinations ( N LR , N LU Extract the peak mutual inductance between the receiver and the U-shaped coil. M UR|max Verify whether it meets the minimum mutual inductance threshold required by the system. M min Ensure that the basic coupling capability meets the standards.

[0066] (4) Construction of Dimensionality Reduction Optimization Model

[0067] To improve optimization efficiency, a dual simplification strategy is implemented: forced alignment of the outer diameter of the U-shaped coil. D LU_out With respect to the outer edge of the circular coil group, and considering the number of turns of the large / small circular coils as a single variable. N LC = N LTL = N LTS The core optimization variable is ultimately defined as the equivalent number of turns. N LC and the spacing between large and small circles d 1.

[0068] (5) Multi-criteria screening of anti-migration performance

[0069] initialization N LC = 1, d Set 1 = 0 and traverse the parameter space to obtain the mutual inductance between the receiver and the composite circular coil. M CR ( y Mutual inductance between the receiver and the U-shaped coil M UR ( y Spatial distribution curves; screening feasible solutions that simultaneously satisfy three constraints: ① Maximum offset distance y max ≥ y allow ② Mutual inductance amplitude balance 0.9 M CR ≤ 2 M UR|max ≤ 1.1 M CR ③ Peak position synchronization 0.9 y | M UR|max ≤2 y |M CR|max ≤ 1.1 y | M UR|max .

[0070] (6) Robust multi-objective optimization decision

[0071] Calculate the equivalent mutual inductance distribution for feasible solution sets. M eq ( y ) = M CR ( y ) + M UR ( y ), Quantitative evaluation indicator: mutual inductance volatility ∆ M = (max( M eq ) - min( M eq )) / max( M eq ) and effective offset range ∆ y = y max Based on the Pareto optimality criterion, select min(∆) M And max(∆) y The compromise solution is to determine the final parameters according to specific system constraints.

[0072] The circuit diagram of the coupling mechanism used in this invention is as follows: Figure 4 As shown, Figure 4 The key parameters and their symbols are shown in Table 1.

[0073] Table 1. Parameters and Symbols

[0074]

[0075] The wireless charging system uses an adjustable DC power input, which is converted to 85 kHz AC power by a half-bridge high-frequency inverter. This AC power is then supplied to the transmitting coil via an LCC-S hybrid compensation topology at the transmitting end. The secondary coil induces an AC electromotive force through magnetic coupling, which is output as a square wave voltage via an S-type compensation topology at the receiving end. An integrated dual-mode control strategy is employed: output characteristic reconstruction is achieved by switching a single AC switch Q3. When Q3 is off, the system exhibits constant current characteristics independent of load impedance and coupling coefficient; when Q3 is on, the system switches to constant voltage characteristics independent of load and coupling. This seamless constant current-constant voltage (CC-CV) switching mechanism precisely matches the charging requirements of the battery load. A passive rectifier bridge is used for rectification and filtering in the subsequent stage, and a DC / DC converter generates an adjustable and stable DC output, ensuring efficient energy transfer across the entire operating range. Core energy efficiency optimization strategies include: selecting a half-bridge inverter to reduce switching losses, integrating an LCC-S / SS compensation topology to improve the power factor, and using a single AC switch Q3 to achieve dual-mode control and simplify the circuit structure.

[0076] Example 2:

[0077] The system parameters and external dimensions of the coupling mechanism designed in this example are shown in Table 2. The influence of the coupling mechanism parameters on mutual inductance fluctuation and offset range is verified using finite element simulation. Based on the minimum mutual inductance requirement of 10 μH, the receiver parameters are shown in Table 3. The simulation yields the curves of mutual inductance between the U-shaped coil and the transmitting coil as a function of horizontal offset distance. M UR like Figure 5 As shown in the diagram. Figure 6 , Figure 7 As shown.

[0078] Table 2 Overall System Design Parameters

[0079]

[0080] Table 3 Receiver Coil Design Parameters

[0081]

[0082] in M UR|max = 6.6μH, y | M UR|max = 140mm. The optimization objective is: mutual inductance fluctuation rate < 5% within a 140mm offset range; according to optimization steps (4)-(6), the specific parameters of the optimized circular coupling mechanism are shown in Table 4, and the curve of the circular mutual inductance changing with the horizontal offset distance is shown in Table 4. Figure 8 As shown in the diagram, the dimensions of the circular transmitting coil are as follows: Figure 9 As shown, Figure 10Finally, by... Figure 5 and Figure 8 The curve showing the change in mutual inductance between the transmitting coil (composed of circular vertically stacked U-shaped coils) and the circular receiving coil as a function of horizontal offset distance is shown in the figure. Figure 11 As shown, its coupling mechanism schematic diagram is as follows: Figure 12 , Figure 13 As shown.

[0083] Table 4 Design parameters of the circular coil at the transmitting end

[0084]

[0085] The final curves of mutual inductance of the coupling mechanism coils at different vertical distances as the horizontal offset distance increases are shown below. Figure 14 As shown, it can be seen that even when vertical offset occurs at the receiving end, good anti-offset performance over horizontal distance can still be maintained.

[0086] Furthermore, the curves showing the change in self-inductance at the receiver and transmitter with increasing horizontal offset distance are as follows: Figure 15 As shown, the fluctuation range of the self-inductance value of the receiving coil is constrained to within ±0.3μH, with a relative change rate ≤2%; the fluctuation range of the self-inductance value of the transmitting coil is constrained to within ±12μH, with a relative change rate ≤2.7%. The relative fluctuation rate of the self-inductance is not large, which will not affect the resonance relationship of the system parameters under offset conditions and the realization of zero-voltage switching.

[0087] The volatility of the system during offset was verified through circuit simulation. In this embodiment, the system frequency is 85kHz and the rated output voltage is 45V. The values ​​of the topology parameters are shown in Table 5.

[0088] Table 5 Simulation Parameter Values

[0089]

[0090] The simulation yielded the output waveforms at offsets of 0mm, 40mm, 80mm, 120mm, and 140mm as follows: Figure 16 As shown in the waveform, with the same input voltage, the output voltage and power of the receiver are approximately equal under the four distance conditions (a)-(e) during the offset process. The change is that it first increases and then decreases, then increases again and then decreases again, which is consistent with the pattern of... Figure 9 , Figure 10 The simulation of the mutual inductance variation trend of the coupling mechanism shows that the output voltage fluctuation rate is approximately 5% during this process, demonstrating the effectiveness of the coupling mechanism design method.

[0091] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optimization method for a high offset tolerance unmanned aerial vehicle (UAV) wireless charging coupling mechanism, characterized in that: A high offset tolerance unmanned aerial vehicle wireless charging coupling mechanism includes a compensation coil (1) and a composite circular coil. The compensation coil and the composite circular coil are connected in series to form a single current loop. The composite circular coil includes a large circular coil (2) and a small circular coil (3). The large circular coil (2) and the small circular coil (3) are connected in series. The compensation coil (1) has a central through hole in the middle, and the compensation coil (1) has a radial through gap as the arm spacing (5). The compensation coil (1) has a C-shaped through hole (6). The method includes the following steps: By adjusting the arm spacing (5) to control the edge magnetic field gradient, the turns ratio of the composite circular coil is optimized to control the central magnetic field strength, so that the total mutual inductance-offset curve satisfies: within the target offset tolerance Δ y Minimize mutual inductance volatility Δ M , or given Δ M Maximize Δ under threshold y .

2. The optimization method for a high offset tolerance unmanned aerial vehicle wireless charging coupling mechanism according to claim 1, characterized in that: The compensation coil (1) and the composite circular coil at the transmitting end adopt a vertically stacked series coil structure; The large circular coil (2) and the small circular coil (3) are set coaxially and in the same plane, and the inner diameter of the large circular coil (2) is larger than the outer diameter of the small circular coil (3); The outer diameter of the compensation coil (1) is aligned with the outer edge of the composite circular coil, and the inner diameter of the U-shaped coil is 67.5% ± 5% of the outer diameter.

3. The optimization method for a high offset tolerance unmanned aerial vehicle wireless charging coupling mechanism according to claim 2, characterized in that: The receiver (4) adopts a discrete strip ferrite array with a strip ferrite thickness of 1mm ± 0.2mm.

4. The optimization method for a high offset tolerance unmanned aerial vehicle wireless charging coupling mechanism according to claim 3, characterized in that: The transmitter adopts a three-layer vertical stacked structure: a circular ferrite substrate (7), a composite circular coil, and a compensation coil (1) are arranged coaxially from bottom to top.

5. The optimization method for a high offset tolerance unmanned aerial vehicle wireless charging coupling mechanism according to claim 4, characterized in that: By combining scanning parameters through finite element simulation, solutions that simultaneously satisfy the following conditions are selected: maximum offset distance. y max ≥ y allow Mutual inductance amplitude balance 0.9 M CR ≤ 2 M UR|max ≤ 1.1 M CR Peak position synchronization 0.9 y | M UR|max ≤ 2 y | M CR|max ≤ 1.1 y | M UR|max ;in, y allow To allow for offset distance, M CR As a reference mutual inductance, M UR|max This represents the maximum value of the actual mutual inductance. y This represents the offset position.

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