4D-4D coupling mechanism and wireless power transmission system

Abstract

The application provides a 4D-4D coupling mechanism and a wireless electric energy transmission system, wherein the 4D-4D coupling mechanism comprises a transmitting end and a receiving end; the transmitting end comprises two groups of coaxially arranged and mutually decoupled DD coils, which are respectively an inner transmitting coil and an outer transmitting coil, and the inner transmitting coil and the outer transmitting coil adopt an inner-outer layer arrangement mode; the receiving end comprises two groups of coaxially arranged and mutually decoupled DD coils, which are respectively an upper receiving coil and a lower receiving coil, and the upper receiving coil and the lower receiving coil adopt an upper-lower layer arrangement mode. Through the innovative design of the coupling mechanism and the cooperative matching of the compensation topology, stable electric energy output can be realized under the combined working conditions of rotational deviation and axial deviation without introducing complex closed-loop control.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and more particularly to a 4D-4D coupling mechanism and a wireless power transmission system. Background Technology

[0002] Rotary bearings are critical components in large industrial equipment such as wind turbines, ships, and drilling equipment. Real-time monitoring of their health status is crucial for ensuring the stable operation of industrial production equipment. Providing a stable and reliable power supply to the rotary bearing monitoring sensors is a fundamental condition for continuous bearing condition monitoring. Currently, rotating devices often use brushes and slip rings for power supply. This technology is relatively mature and widely used. However, in actual operation, problems such as wear, heat generation, and electrical sparks are still unavoidable. Long-term service may adversely affect the safety and reliability of equipment operation.

[0003] Wireless Power Transfer (WPT) technology can achieve isolated power transfer through resonant topology, thus avoiding the mechanical wear problems of contact power supply and offering higher safety and reliability. However, in practical applications, positional misalignment between the transmitting and receiving coils is unavoidable, causing changes in system mutual inductance, which in turn leads to output fluctuations and even affects the reliability of system operation. Therefore, offset resistance has always been an important research focus in the field of wireless power transfer.

[0004] Existing anti-migration techniques have the following main shortcomings:

[0005] (1) Schemes using pulse frequency modulation (PFM) control or pulse width modulation (PWM) control usually require the introduction of closed-loop control and communication links, additional sampling circuits, and sometimes DC / DC conversion links, thereby increasing the system control complexity and cost, and are not suitable for some harsh working conditions with high-frequency vibration.

[0006] (2) In some dual-transmitting coil and single-receiving coil coupling mechanisms, there is coupling between the transmitting coils. When the coil is deflected, it will cause a change in the coil self-inductance, thus affecting the resonance characteristics.

[0007] (3) In the scheme based on SS and LCC / LCC hybrid compensation topology, the coil in the coupling mechanism cannot be decoupled when rotating, which is not suitable for rotating shaft application scenarios.

[0008] (4) Although the existing coupling coil structure suitable for rotating scenarios can solve the problem of zero coupling point of mutual inductance during rotation, its axial offset capability is still weak. Summary of the Invention

[0009] The present invention aims to provide a 4D-4D coupling mechanism and a wireless power transmission system that overcomes or at least partially solves the above-mentioned problems.

[0010] To achieve the above objectives, the technical solution of the present invention is specifically implemented as follows:

[0011] A first aspect of the present invention provides a 4D-4D coupling mechanism, comprising: a transmitter and a receiver;

[0012] The transmitting end includes: two sets of coaxially arranged and decoupled DD coils, namely an inner transmitting coil and an outer transmitting coil, wherein the inner transmitting coil and the outer transmitting coil are arranged in an inner and outer layer manner;

[0013] The receiving end includes two sets of coaxially arranged and decoupled DD coils, namely an upper receiving coil and a lower receiving coil, which are arranged in an upper and lower layer configuration.

[0014] Optionally, the magnetic field directions of the inner transmitting coil and the outer transmitting coil are orthogonal to each other, and the magnetic field directions of the upper receiving coil and the lower receiving coil are orthogonal to each other.

[0015] Optionally, the transmitting end is tightly wound around the surface of the rotating drill rod, and the receiving end is fixed to the inner surface of the stator.

[0016] Optionally, the coupling mechanism further includes an eddy current shielding layer, the size of which is configured to improve the anti-displacement performance of the coupling mechanism under rotational displacement conditions.

[0017] A second aspect of the present invention provides a wireless power transmission system, including the above-described 4D-4D coupling mechanism and a cross-coupled dual receiver LCC-S compensation topology;

[0018] The LCC-S compensation topology uses an LCC compensation network for the transmitter and an S-series compensation network for the receiver. The transmitter has two transmitting branches and the receiver has two receiving branches. The transmitter and receiver form a cross-coupled structure, and the two receiving branches use a series output structure to jointly supply power to the load.

[0019] Optionally, the system satisfies the following resonance condition:

[0020]

[0021] in, For the self-inductance of the internal emitter coil, For external transmitting coil, For the upper receiving coil, For the lower receiving coil, The imaginary unit, The system's operating angular frequency satisfies , , , These are the series compensation inductor, parallel compensation capacitor, and series compensation capacitor of the LCC compensation network at the transmitter. and These are the series compensation capacitors for the upper and lower receiving branches, respectively.

[0022] Optionally, when the 4D-4D coupling mechanism undergoes rotational and axial displacement, the output voltages of the two receiving branches exhibit complementary variation characteristics.

[0023] Optionally, the voltage gain of the system is expressed as:

[0024]

[0025] in, The mutual inductance between the inner transmitting coil and the upper receiving coil, This indicates the mutual inductance between the inner transmitting coil and the lower receiving coil. This indicates the mutual inductance between the external transmitting coil and the upper receiving coil. This indicates the mutual inductance between the external transmitting coil and the lower receiving coil. To compensate for the inductance value.

[0026] Therefore, it can be seen that the 4D-4D coupling mechanism and wireless power transmission system provided by this invention, through the innovative design of the coupling mechanism and the synergistic cooperation of the compensation topology, can achieve stable power output under combined working conditions of rotational offset and axial offset without the introduction of complex closed-loop control. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the planar structure of the 4D-4D coupling mechanism provided in an embodiment of the present invention;

[0029] Figure 2 A three-dimensional structural schematic diagram of the 4D-4D coupling mechanism provided in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of a dual-receiver LCC-S compensation topology provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram illustrating the variation of total mutual inductance with rotation angle under different axial offset distances provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the simulation and experimental results of mutual inductance changing with rotation angle under different axial offset distances provided in the embodiments of the present invention;

[0033] Figure 6 This is a schematic diagram illustrating the change of output voltage with rotation angle under different axial offset distances provided in an embodiment of the present invention.

[0034] Figure 7 This is a schematic diagram illustrating the change in transmission efficiency with rotation angle at different axial offset distances, as provided in an embodiment of the present invention. Detailed Implementation

[0035] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey its scope.

[0036] This is provided to those skilled in the art.

[0037] Figure 1 This diagram shows a planar structure schematic of the 4D-4D coupling mechanism provided in an embodiment of the present invention. Figure 2 A three-dimensional structural schematic diagram of the 4D-4D coupling mechanism provided in an embodiment of the present invention is shown below. Figure 1 The 4D-4D coupling mechanism provided in this embodiment of the invention includes: a transmitter and a receiver;

[0038] The transmitting end includes: two sets of coaxially arranged and decoupled DD coils, namely an inner transmitting coil and an outer transmitting coil, wherein the inner transmitting coil and the outer transmitting coil are arranged in an inner and outer layer manner;

[0039] The receiving end includes two sets of coaxially arranged and decoupled DD coils, namely an upper receiving coil and a lower receiving coil, which are arranged in an upper and lower layer configuration.

[0040] Specifically, the 4D-4D coupling mechanism provided in this embodiment of the invention consists of 8 basic coil units, including 4 transmitting coils and 4 receiving coils, such as... Figure 1 As shown, where, The length of the downstream receiving coil. The height of the lower-level receiving coil. The length of the upstream receiving coil. This refers to the height of the upper-level receiving coil. The upper-level receiving coil and the lower-level receiving coil are placed coaxially and parallel. The length of the outer transmitting coil. The height of the outer transmitting coil. The length of the inner transmitting coil. This refers to the height of the inner transmitting coil. To avoid the two transmitting coils completely overlapping, Slightly smaller The inner and outer transmitting coils are placed in an overlapping manner.

[0041] In an optional embodiment of the present invention, the magnetic field directions of the inner transmitting coil and the outer transmitting coil are orthogonal to each other, and the magnetic field directions of the upper receiving coil and the lower receiving coil are orthogonal to each other. Furthermore, the transmitting end is tightly wound around the surface of the rotating shaft, and the receiving end is fixed to the inner surface of the stator.

[0042] Specifically, the transmitting end consists of two sets of DD coils with orthogonal magnetic field directions, arranged in inner and outer layers, and tightly wound around the surface of the rotating drill rod; the receiving end consists of two sets of DD coils with orthogonal magnetic field directions, arranged in upper and lower layers, and can be fixed to the inner surface of the stator. Based on the structural characteristics of the DD coils and the orthogonal magnetic field layout, decoupling can be achieved between the transmitting coils and between the receiving coils, thereby reducing the fluctuation of mutual inductance during rotational and axial offsets and improving the transmission stability of the coupling mechanism.

[0043] As an optional embodiment of the present invention, the coupling mechanism further includes an eddy current shielding layer, the size of which is configured to improve the anti-displacement performance of the coupling mechanism under rotational displacement conditions.

[0044] Specifically, to improve the rotational resistance to displacement of the coupling mechanism, this invention adds an eddy current shielding layer to the structure of the coupling mechanism. The size of the eddy current shielding layer is an important parameter affecting the rotational resistance to displacement performance, while the axial height of the coupling mechanism is closely related to its axial resistance to displacement. To balance rotational resistance to displacement performance and meet the stable energy transfer requirements under a specific axial displacement distance, this invention can use finite element analysis software to simulate and optimize the parameters of the coupling mechanism.

[0045] based on Figure 1 and Figure 2 The present invention also provides a wireless power transmission system, including the above-described 4D-4D coupling mechanism and a cross-coupled dual receiver LCC-S compensation topology.

[0046] The LCC-S compensation topology uses an LCC compensation network for the transmitter and an S-series compensation network for the receiver. The transmitter has two transmitting branches and the receiver has two receiving branches. The transmitter and receiver form a cross-coupled structure, and the two receiving branches use a series output structure to jointly supply power to the load.

[0047] Specifically, the dual-receiver LCC-S compensation topology provided in this embodiment of the invention is as follows: Figure 3 As shown, the inverter can be a full-bridge inverter, which may include four power MOSFETs; the rectifier can be a high-frequency rectifier diode, for example, it may include two receiving branches, each of which uses two high-frequency rectifier diodes, for a total of four; the resonant cavity may include two transmitting coils and two receiving coils, with each receiving coil forming a receiving branch. For the self-inductance of the internal emitter coil, For the self-inductance of the external transmitting coil, For the self-inductance of the receiving coil, The self-inductance of the receiving coil; , These are the equivalent output voltage and equivalent output current of the full-bridge inverter; It is the equivalent output voltage of the receiving rectifier circuit. This is the equivalent output voltage of the receiving rectifier circuit. It is the equivalent input current of the receiving rectifier circuit. This is the equivalent input current of the receiving rectifier circuit; This is the equivalent load seen from the input terminal of the upper rectifier bridge. This is the equivalent load seen from the input of the lower rectifier bridge. and These represent the equivalent load borne by the two receiving ends. This represents the total system load. Furthermore, This indicates the mutual inductance between the inner and outer transmitting coils. This indicates the mutual inductance between the upper and lower receiving coils. This indicates the mutual inductance between the inner transmitting coil and the upper receiving coil. This indicates the mutual inductance between the inner transmitting coil and the lower receiving coil. This indicates the mutual inductance between the external transmitting coil and the upper receiving coil. This indicates the mutual inductance between the external transmitting coil and the lower receiving coil. In this invention, there is cross-coupling between the coils at both the transmitting and receiving ends, and the receiving side employs a structure with two rectifiers connected in series for output.

[0048] As an optional embodiment of the present invention, the system satisfies the following resonance condition:

[0049]

[0050] in, For the self-inductance of the internal emitter coil, For external transmitting coil, For the upper receiving coil, For the lower receiving coil, The imaginary unit, The system's operating angular frequency satisfies , , , These are the series compensation inductor, parallel compensation capacitor, and series compensation capacitor of the LCC compensation network at the transmitter. and These are the series compensation capacitors for the upper and lower receiving branches, respectively.

[0051] Specifically, through Figure 1 and Figure 2 The magnetic coupling mechanism shown allows the transmitting coil to... and Between and receiving coil and Magnetic decoupling is achieved between them, that is, satisfying , Based on this, the mesh current equations can be written according to the equivalent circuit shown in the figure as follows:

[0052]

[0053] Because it operates in a resonant state, the system parameters should satisfy:

[0054]

[0055] Neglecting the internal resistance of the coil, we can obtain:

[0056]

[0057] From the formula It can be seen that when , , ,hour, , Therefore, when the receiving coil deviates significantly from the working area or is removed, the current stress flowing through the inverter switching transistor and the current stress of the transmitting coils Lp1 and Lp2 will not increase significantly. This overcomes the problem of excessive current stress in the transmitting coil when the mutual inductance of the SS compensation topology decreases sharply.

[0058] Analytical The equivalent input impedance of the system can be obtained as follows:

[0059]

[0060] From the formula As can be seen, since the impedance expression has no imaginary part, the system's input impedance is resistive, achieving ZPA (Zero Phase Angle), which helps reduce switching losses.

[0061] As an optional embodiment of the present invention, the voltage gain of the system is expressed as:

[0062]

[0063] in, The mutual inductance between the inner transmitting coil and the upper receiving coil, This indicates the mutual inductance between the inner transmitting coil and the lower receiving coil. This indicates the mutual inductance between the external transmitting coil and the upper receiving coil. This indicates the mutual inductance between the external transmitting coil and the lower receiving coil. To compensate for the inductance value.

[0064] Specifically, combining the above equations and the fundamental equivalent analysis method, the system voltage gain can be obtained as follows:

[0065]

[0066] From the formula It can be seen that the system output voltage is only related to the compensation inductor. Mutual inductance between the transmitting coil and the receiving coil The sum and input voltage It depends on the size, when and Once determined, if the sum of the mutual inductance between the transmitting coil and the receiving coil can remain unchanged during the offset process, a constant voltage output can be achieved.

[0067] As an optional embodiment of the present invention, when the 4D-4D coupling mechanism undergoes rotational and axial displacement, the output voltages of the two receiving branches exhibit complementary change characteristics.

[0068] Specifically, mutual inductance and coupling coefficient are important parameters characterizing the coupling state between the transmitter and receiver. As the relative positions of the transmitting and receiving coils change, the mutual inductance changes accordingly; reducing the rate of change of mutual inductance helps improve the transmission stability of the coupling mechanism. This invention, the LCC-S coupled dual-receiver, requires decoupling between the transmitting coils and between the receiving coils. Simultaneously, during the offset process, the two sets of coupling channels should exhibit an inverse relationship, i.e., the output of one coil loop increases while the output of the other decreases, thus ensuring that the total system output maintains relatively small fluctuations during the offset process, forming an approximately constant voltage output characteristic.

[0069] The 4D-4D coupling mechanism and wireless power transmission system provided by the present invention operate in an open-loop control mode. The control process includes: the inverter drives the transmitter compensation network at a fixed operating frequency; through the synergistic effect of the 4D-4D coupling mechanism and the LCC-S compensation topology, the system achieves an approximately constant output voltage under rotational and axial offset conditions.

[0070] Specifically, when the coupling mechanism experiences rotational or axial displacement, the mutual inductance between the two transmitting coils and the two receiving coils in the 4D-4D coupling mechanism changes in a trade-off—the output voltage of one receiving branch increases, while the output voltage of the other receiving branch decreases. Since the two receiving branches employ a series output structure, fluctuations in the total output voltage are effectively suppressed, thus achieving an approximately constant voltage output. This open-loop control method avoids additional sampling circuits and DC / DC conversion stages, reducing system control complexity and cost, and is suitable for harsh operating conditions with high-frequency vibrations.

[0071] As can be seen, the 4D-4D coupling mechanism and wireless power transmission system provided by the embodiments of the present invention, through the special design of the 4D-4D coupling mechanism, enable the system to exhibit the characteristic of complementary changes in the output voltage of the two receiving branches during the offset process: when the coupling mechanism undergoes rotational offset or axial offset, the output voltage of one receiving branch increases, while the output voltage of the other receiving branch decreases, thereby keeping the total output voltage relatively stable and forming an approximately constant voltage output characteristic.

[0072] Furthermore, since decoupling is achieved between the transmitting coils and between the receiving coils, the system's input impedance is resistive, achieving zero phase angle (ZPA), which helps reduce switching losses.

[0073] The following, combined with Figure 4 The invention is further illustrated by simulation of the coil offset characteristics:

[0074] Simulation analysis of the coupling mechanism in During rotation The variation law of total mutual inductance under axial offset is shown in the following figure. Figure 4 As shown. By Figure 4 It can be seen that as the axial offset distance increases, the total mutual inductance generally decreases, indicating that the coupling ability between the coils gradually weakens. This is because the axial offset increases the equivalent air gap between the transmitting and receiving coils, lengthens the magnetic flux path, and consequently increases the magnetic reluctance of the coupling mechanism and decreases the main magnetic flux, ultimately reducing the total mutual inductance. When the axial offset distance is... Rotation angle is At this time, the total mutual inductance is at its maximum, which is When the axial offset distance is Rotation angle is At this time, the total mutual inductance is minimized, which is Therefore, it can be calculated that during rotation... And the axial offset range does not exceed Under the aforementioned operating conditions, the mutual inductance offset rate is 19.55%. The results show that the designed 4D-4D coupling mechanism can maintain relatively stable coupling performance under the above-mentioned combined offset conditions, thus ensuring effective power transmission of the system.

[0075] Meanwhile, in order to verify the mutual inductance stability and constant voltage output characteristics of the proposed 4D-4D coupling mechanism during rotational and axial offset processes, the present invention can also build a corresponding experimental platform.

[0076] First, the mutual inductance between the transmitting and receiving coils under different offset conditions was measured using an LCR bridge, and the variation law of the mutual inductance with rotation angle and axial offset distance was analyzed. Then, a complete WPT experimental system was constructed, and the system output voltage was measured and analyzed.

[0077] The variation law of mutual inductance of the 4D-4D coupled mechanism with rotation angle and axial offset distance was obtained through simulation and experiment. The results are as follows: Figure 5 As shown. Experimental results indicate that mutual inductance is closely related to the rotation angle and axial offset distance. When the rotation angle is... axial offset distance is At that time, mutual inductance reaches its maximum value. When the rotation angle is axial offset distance is hour,

[0078] Mutual inductance reduced to minimum value The corresponding mutual inductance retention rate was 78.29%. Overall, the experimental curves and simulation curves showed largely consistent trends, verifying the rationality of the finite element simulation results and the coupling mechanism design. However, some discrepancies still existed between the two under certain operating conditions, particularly at rotation angles of [missing information]. axial offset distance is At that time, the simulated mutual inductance value was 26.04 uH, and the experimental mutual inductance value was 27.72 uH, with a relative error of approximately 6.5%. This error mainly stems from the limited winding precision of the experimental coil, as well as the unavoidable differences between the actual coil size, relative position, and axial offset distance and the simulation model.

[0079] The output voltage and transmission efficiency vary with the relative rotation angle between the transmitting and receiving coils as follows: Figure 6 and Figure 7 As shown in the figure, the output voltage variation trend of the simulation results is basically consistent with that of the experimental results. Rotation and axial offset range not exceeding Under the combined offset condition, the maximum output voltage of the system is Minimum output voltage is The corresponding voltage retention rate is 78.3%; the maximum transmission efficiency of the system is 85.94%, the minimum transmission efficiency is 74.76%, and the corresponding efficiency retention rate is 87.0%. Experimental results show that although rotation and axial offset cause changes in coil mutual inductance, the proposed 4D-4D coupling mechanism can still maintain high output voltage and transmission efficiency, and has good anti-offset capability and operational stability, thus verifying the effectiveness of the coupling mechanism under the combined rotation-axial offset condition.

[0080] In summary, the present invention has the following beneficial effects:

[0081] (1) Excellent composite anti-offset capability: Through the innovative design of the 4D-4D coupling mechanism, magnetic decoupling is achieved between the transmitting coil and between the receiving coil. Combined with the complementary output characteristics of the cross-coupled dual receiver LCC-S compensation topology, the system can still maintain a stable output voltage under the combined conditions of rotational offset and axial offset. Experimental results show that under the condition of 360° rotation and axial offset range not exceeding 5cm, the system mutual inductance retention rate and output voltage retention rate reach 78.29% and 78.3% respectively, and the transmission efficiency is maintained in the range of 74.76% to 85.94%.

[0082] (2) No need for complex closed-loop control: The present invention adopts an open-loop control method, which does not require the introduction of closed-loop feedback control or communication links, avoids additional sampling circuits and DC / DC conversion links, reduces the complexity and cost of system control, and is suitable for harsh working conditions with high-frequency vibration.

[0083] (3) Applicable to rotating shaft application scenarios: Both the transmitting coil and the receiving coil adopt the DD coil structure arranged coaxially, and the magnetic field direction is orthogonal to achieve decoupling. It can adapt to the offset changes of rotating shaft equipment during rotation, and is particularly suitable for the power supply scenarios of rotating bearing monitoring sensors such as wind turbines, ships and drilling equipment.

[0084] (4) Low switching stress and high reliability: Due to the decoupling between the transmitting coils, when the receiving coil deviates significantly from the working area or is removed, the current stress flowing through the inverter switching tube and the current stress of the transmitting coil will not increase significantly, overcoming the problem of excessive current stress in the transmitting coil when the mutual inductance of the traditional SS compensation topology decreases sharply.

[0085] (5) High system efficiency: The system input impedance is resistive, achieving zero phase angle, reducing switching losses, and improving the overall transmission efficiency of the system.

[0086] It is worth noting that the 4D-4D coupling mechanism and wireless power transmission system of the present invention are applicable to rotary axis applications, including but not limited to:

[0087] (1) Wireless power supply for monitoring sensors of rotating bearings of wind turbine units;

[0088] (2) Wireless power supply for monitoring equipment of the rotating shaft of the ship's propulsion system;

[0089] (3) Wireless power supply for the rotary steering system of drilling equipment;

[0090] (4) Wireless power supply between rotating and stationary parts in other industrial rotating equipment.

[0091] In the above application scenarios, the transmitting end can be tightly wound around the surface of the rotating drill rod and rotate with the drill rod; the receiving end can be fixed to the inner surface of the stator and remain stationary. The system can maintain stable power output within a 360° rotation and a certain axial offset range.

[0092] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0093] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A 4D-4D coupling mechanism, characterized in that, include: Transmitter and receiver; The transmitting end includes: two sets of coaxially arranged and decoupled DD coils, namely an inner transmitting coil and an outer transmitting coil, wherein the inner transmitting coil and the outer transmitting coil are arranged in an inner and outer layer manner; The receiving end includes two sets of coaxially arranged and decoupled DD coils, namely an upper receiving coil and a lower receiving coil, which are arranged in an upper and lower layer configuration.

2. The 4D-4D coupling mechanism according to claim 1, characterized in that, The magnetic field directions of the inner transmitting coil and the outer transmitting coil are orthogonal to each other, and the magnetic field directions of the upper receiving coil and the lower receiving coil are orthogonal to each other.

3. The 4D-4D coupling mechanism according to claim 1, characterized in that, The transmitting end is tightly wound around the surface of the rotating drill rod, and the receiving end is fixed to the inner surface of the stator.

4. The 4D-4D coupling mechanism according to claim 1, characterized in that, The coupling mechanism also includes an eddy current shielding layer, the size of which is configured to improve the anti-offset performance of the coupling mechanism under rotational offset conditions.

5. A wireless power transmission system, characterized in that, Includes the 4D-4D coupling mechanism as described in any one of claims 1 to 4, and the cross-coupled dual receiver LCC-S compensation topology; The LCC-S compensation topology uses an LCC compensation network for the transmitter and an S-series compensation network for the receiver. The transmitter uses one transmitting branch and the receiver uses two receiving branches. The transmitter and receiver form a cross-coupled structure, and the two receiving branches use a series output structure to jointly supply power to the load.

6. The wireless power transmission system according to claim 5, characterized in that, The system satisfies the following resonance condition: ， in, For the self-inductance of the internal emitter coil, For external transmitting coil, For the upper receiving coil, For the lower receiving coil, The imaginary unit, The system's operating angular frequency satisfies , , , These are the series compensation inductor, parallel compensation capacitor, and series compensation capacitor of the LCC compensation network at the transmitter. and These are the series compensation capacitors for the upper and lower receiving branches, respectively.

7. The wireless power transmission system according to claim 5, characterized in that, When the 4D-4D coupling mechanism undergoes rotational and axial displacement, the output voltages of the two receiving branches exhibit complementary variation characteristics.

8. The wireless power transmission system according to claim 5, characterized in that, The voltage gain of the system is expressed as: ， in, The mutual inductance between the inner transmitting coil and the upper receiving coil, This indicates the mutual inductance between the inner transmitting coil and the lower receiving coil. This indicates the mutual inductance between the external transmitting coil and the upper receiving coil. This indicates the mutual inductance between the external transmitting coil and the lower receiving coil. To compensate for the inductance value.

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