Undersea magnetic coupling resonant wireless power transmission magnetic shielding system and method

Abstract

The invention provides an undersea magnetic coupling resonant wireless power transmission magnetic shielding system and method, and belongs to the technical field of wireless power transmission. Comprising a high-frequency inverter, a transmitting end compensation network, a magnetic coupling mechanism, a receiving end series compensation network and a rectification filter circuit. A multi-gradient composite structure of an embedded central nanocrystalline shielding layer, a coil back nanocrystalline shielding layer and an aluminum foil shielding layer is innovatively integrated in a coupling mechanism, and the embedded central nanocrystalline shielding layer can directionally restrain central leakage magnetic fields of a circular coil and a runway coil, so that axial magnetic field diffusion is reduced; and more magnetic induction lines are concentrated in a coupling area, so that the energy transmission efficiency in a seawater environment is directly improved. The nanocrystalline shielding layer on the back of the coil has the characteristic of high magnetic conductivity, can effectively block a leakage magnetic field radiated from the coil to the interior of an aircraft, avoids electromagnetic interference to internal electronic equipment, and meanwhile reduces energy loss.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission technology, specifically relating to an underwater magnetic coupling resonant wireless power transmission magnetic shielding system and method. Background Technology

[0002] With the rapid development of marine resource development and deep-sea exploration, the convenience and reliability of underwater vehicle refueling have become core bottlenecks restricting their operational range and efficiency. Traditional wired plug-in charging methods are limited by problems such as the difficulty of sealing under high underwater pressure, the susceptibility of interfaces to corrosion and wear from seawater, and stringent requirements for docking precision, making it difficult to meet the endurance requirements of underwater vehicles for long-term, continuous operation. Magnetic coupling resonant wireless power transfer technology, with its advantages of non-contact operation, no mechanical wear, and strong anti-interference capabilities, has become the core technical path to solve the problem of underwater vehicle refueling. However, the special underwater working environment brings many unique technical challenges to the engineering implementation of this technology.

[0003] The underwater environment is characterized by high pressure, high dielectric constant (the dielectric constant of seawater is much higher than that of air), high salt corrosion, and dense surrounding metal structures (the hull of the underwater vehicle, the underwater work platform, etc. are all made of metal). These characteristics place multiple stringent requirements on the magnetic shielding design of wireless power transmission systems: On the one hand, the high dielectric environment of the underwater environment will exacerbate the attenuation and diffusion of the magnetic field, resulting in a significant reduction in energy transmission efficiency. It is necessary to constrain the magnetic field distribution through an efficient magnetic shielding structure to improve the utilization rate of the magnetic field. On the other hand, the dense surrounding metal structures are prone to eddy current loss and magnetic field distortion under the action of alternating magnetic fields. This will not only further lose transmitted energy, but may also interfere with the normal operation of the precision electronic equipment (such as sensors and control systems) inside the underwater vehicle. It is necessary to achieve effective suppression of the magnetic field across the entire frequency band.

[0004] Currently, magnetic shielding technologies in the field of magnetically coupled resonant wireless power transmission are mostly designed for conventional environments such as land or air. Their shielding structures, material selections, and performance optimization goals are not fully adapted to the special underwater operating conditions. Existing shielding structures are mostly non-embedded designs, which have poor compatibility with the streamlined structure of underwater vehicles and can easily increase navigation drag. At the same time, their material and sealing designs do not take into account the effects of the high pressure and high salt corrosion environment underwater, which can easily lead to performance degradation and structural damage with long-term use.

[0005] Crucially, existing shielding technologies are not specifically designed to address the interference characteristics of underwater metallic environments. They lack a refined magnetic field constraint mechanism for metallic interference and fail to achieve coordinated optimization of the shielding structure, coupling mechanism, and compensation network. This results in problems such as resonant frequency shift, transmission efficiency fluctuations, and insufficient electromagnetic compatibility in underwater metallic environments, making it difficult to meet the actual needs of underwater vehicles for high power and stable endurance resupply.

[0006] To address the aforementioned pain points specific to underwater technologies, there is an urgent need for a magnetic shielding system that adapts to the structural characteristics of underwater vehicles, balances full-band magnetic field suppression and efficient energy transmission, and possesses excellent environmental adaptability and long-term reliability. This invention, based on the concept of gradient composite shielding, innovatively designs a multi-dimensional synergistic protection structure consisting of an embedded central nanocrystalline shielding layer, a coil-back nanocrystalline shielding layer, and an aluminum foil shielding layer. Combined with proprietary material preparation processes and parameter optimization strategies, it achieves comprehensive improvements in magnetic field confinement, interference suppression, environmental adaptability, and performance stability. This overcomes the limitations of existing technologies in underwater applications and provides core technical support for the engineering application of wireless power transmission systems for underwater vehicles. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned shortcomings and provide an underwater magnetically coupled resonant wireless power transmission magnetic shielding system and method. It is applicable to non-contact power supply scenarios for underwater vehicles (such as unmanned underwater vehicles and underwater robots), aiming to better adapt to the technical requirements of special underwater working conditions by solving the problems of magnetic shielding and efficient energy transmission under high voltage, high dielectric, and metallic environment interference.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides an underwater magnetically coupled resonant wireless power transmission magnetic shielding system, comprising a transmitting unit and a receiving unit. The transmitting unit includes a transmitting coil and a transmitting shielding structure, and the receiving unit includes a receiving coil and a receiving shielding structure. The transmitting coil and the receiving coil are coupled by a spatial magnetic field, and the transmitting shielding structure and the receiving shielding structure are multi-layer shielding structures.

[0009] The transmitting coil is a circular coil, and the receiving coil is a racetrack-shaped coil.

[0010] The transmitting coil is embedded in the transmitting shielding structure, which includes: a central nanocrystalline shielding layer, an aluminum foil shielding layer, and a rear nanocrystalline shielding layer. The aluminum foil shielding layer and the rear nanocrystalline shielding layer form a disk structure, and the central nanocrystalline shielding layer protrudes from the center of the disk structure and is embedded in the transmitting coil.

[0011] The receiving coil is embedded in the receiving shield structure, which includes: a central nanocrystalline shielding layer, an aluminum foil shielding layer, and a rear nanocrystalline shielding layer. The aluminum foil shielding layer and the rear nanocrystalline shielding layer form a square disk structure, and the central nanocrystalline shielding layer protrudes from the center of the square disk structure and is embedded in the receiving coil.

[0012] The transmitting and receiving units incorporate a high-frequency inverter module, a transmitting-end resonant compensation network, a magnetic coupling mechanism, a receiving-end resonant compensation network, and a rectifier filter circuit. The transmitting-end resonant compensation network and the receiving-end resonant compensation network adopt the LCC-S compensation network.

[0013] Secondly, the present invention provides a magnetic shielding method for underwater magnetic coupling resonant wireless power transfer, comprising the following steps: Based on Kirchhoff's laws and the fundamental wave equivalence method, an equivalent circuit model of a magnetically shielded system for wireless power transmission in the presence of metallic materials is established. This equivalent circuit model includes an equivalent voltage source. V ab LCC-S compensation network, equivalent load R eq The equivalent circuit of the transmitting and receiving metal plates; Based on the established equivalent circuit model, split-side compensation is adopted to perform split-side resonance on the transmitter resonance compensation network and the receiver resonance compensation network of the LCC-S compensation network. Calculate the transmission efficiency of the equivalent circuit model under the condition that the transmitting end resonant compensation network and the receiving end resonant compensation network are resonant on both sides. Based on the transmission efficiency of the equivalent circuit model, the necessity of electromagnetic shielding design for the wireless power transmission magnetic shielding system is determined.

[0014] The equivalent circuit model treats the seawater eddy effect as an introduced additional resistance.

[0015] In the step of establishing an equivalent circuit model of a magnetically shielded wireless power transmission system with metallic materials based on Kirchhoff's laws and the fundamental wave equivalence method, the Kirchhoff voltage equation of the equivalent circuit model is as follows:

[0016]

[0017] in, The DC resistance of the transmitting coil, Let Lr be the equivalent resistance of the eddy current loss of the inductor. The imaginary unit; Angular frequency; The self-inductance of the transmitting coil; For the transmitting coil and The first compensation capacitor connected in series, This represents the current in the transmitting coil. The compensating inductance for the transmitting coil, For the input current, Let be the magnetic field coupling coefficient between the transmitting unit and the receiving unit. For the receiving end current, This refers to the input voltage. For load resistance, The inherent resistance of the receiving coil. The equivalent resistance for eddy current losses at the receiving end is... This is the third compensation capacitor at the receiving end.

[0018] In the step of performing split-side resonance on the transmitter and receiver resonance compensation networks of the LCC-S compensation network based on the established equivalent circuit model and using split-side compensation, the conditions for performing split-side resonance on the transmitter and receiver resonance compensation networks are as follows:

[0019] in, For the transmitting coil and Together they form the second compensation capacitor of the resonant compensation circuit. For the self-inductance of the receiving coil, This is the compensation capacitor for the receiving coil.

[0020] Under the condition that the transmitting-end resonant compensation network and the receiving-end resonant compensation network are in separate-side resonance, the transmission efficiency of the equivalent circuit model is calculated as follows:

[0021] in, This represents the transmission efficiency of the equivalent circuit model.

[0022] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a magnetically shielded system and method for underwater magnetically coupled resonant wireless power transmission. Through the integrated design of a circular coil, a runway-shaped coil, and a multi-layer nanocrystalline-aluminum foil composite shielding structure, combined with an LCC-S compensation network and an equivalent circuit model accurately considering seawater eddy current effects, the efficiency and reliability of the underwater magnetically coupled resonant wireless power transmission system are effectively improved, providing a practical solution for long-term, high-power wireless power supply to underwater equipment. The coupling mechanism innovatively integrates a multi-gradient composite structure of a central nanocrystalline shielding layer, a nanocrystalline shielding layer on the back of the coil, and an aluminum foil shielding layer. The central nanocrystalline shielding layer can directionally constrain the central leakage magnetic field of the circular and runway-shaped coils, reducing axial magnetic field diffusion and concentrating more magnetic field lines in the coupling area, directly improving energy transmission efficiency in seawater environments. The nanocrystalline shielding layer on the back of the coil has high permeability, effectively blocking leakage magnetic fields radiated from the coil into the vessel, avoiding electromagnetic interference to internal electronic equipment, and reducing energy loss. The soft-switching characteristics of the LCC-S resonant topology reduce switching losses and electromagnetic interference, further improving the system's efficiency and reliability.

[0023] Furthermore, the aluminum foil shielding layer has excellent eddy current attenuation effect on high-frequency magnetic fields, which can further weaken the stray magnetic fields that the nanocrystalline shielding layer cannot completely block, forming a dual shielding effect of "magnetic resistance + eddy current", which significantly reduces magnetic field leakage in underwater high conductivity environments.

[0024] Furthermore, the three-layer shielding structure provides gradient protection. Even if one layer experiences performance degradation due to extreme environments, the other two layers can still maintain basic shielding capabilities, significantly improving the system's redundancy and reliability. The aluminum foil shielding layer can suppress parasitic capacitance between coils, reduce energy loss caused by high-frequency resonance, and simultaneously lower the system's electromagnetic radiation level, improving electromagnetic compatibility with other electronic systems in the aircraft.

[0025] Furthermore, the receiver adopts a runway-shaped flat nested structure, which can fit closely to the streamlined hull of the underwater vehicle without adding extra drag. This maximizes the effective coupling length of the coil, avoiding the insufficient coupling area problem caused by the diameter limitation of traditional circular coils in narrow layouts. The elongated coupling area design of the runway-shaped coil ensures effective coupling even when the vehicle experiences a certain degree of horizontal or angular misalignment during docking, reducing the requirements for docking accuracy. Within the same installation space, the effective coupling area of ​​the runway-shaped coil is larger than that of a circular coil, improving magnetic field utilization and maintaining stable power transmission efficiency even in the high-dielectric environment of the sea. The shorter heat dissipation path, combined with natural underwater cooling, effectively reduces the temperature rise of the coil during operation, improving the long-term stability of the system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a runway-shaped coupling mechanism. Figure 2 This is a schematic diagram of a magnetic shielding system.

[0027] Figure 3 This is a schematic diagram of the structure of a magnetic shielding system.

[0028] Figure 4 This is a topology diagram of the underwater wireless power transmission system involved in this invention.

[0029] Figure 5 This is the equivalent circuit diagram of the underwater wireless power transmission system involved in this invention.

[0030] Figure 6 This is the equivalent circuit model of the influence of metals on the electrical parameters of the system involved in this invention.

[0031] The following are the labels in the figure: 1. Transmitter coil; 11. Transmitter center nanocrystalline shielding layer; 12. Transmitter aluminum foil shielding layer; 13. Transmitter back nanocrystalline shielding layer; 2. Receiver coil; 21. Receiver center nanocrystalline shielding layer; 22. Receiver aluminum foil shielding layer; 23. Receiver back nanocrystalline shielding layer. Detailed Implementation

[0032] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0033] Example 1 A marine magnetically coupled resonant wireless power transfer magnetic shielding system, the structure of which is as follows: like Figures 1-3 As shown, an underwater magnetically coupled resonant wireless power transmission magnetic shielding system mainly includes a transmitting unit and a receiving unit located in a seawater environment. The transmitting unit is typically installed on a surface platform or an underwater fixed base station, while the receiving unit is installed at the load end of underwater vehicles, observation equipment, etc.

[0034] Furthermore, the transmitting unit mainly includes a transmitting coil 1, a transmitting shielding structure, and a power conversion circuit integrated within the housing. Correspondingly, the receiving unit mainly includes a receiving coil 2, a receiving shielding structure, and a power processing circuit integrated within the housing.

[0035] Preferably, to accommodate the installation space of underwater equipment and optimize the magnetic field distribution, the transmitting coil 1 is a circular coil, and the receiving coil 2 is designed as a racetrack-shaped coil. This shape helps to obtain higher inductance and coupling coefficient within a limited area. Both the transmitting and receiving shielding structures are multi-layer composite shielding structures, designed to effectively suppress energy loss and magnetic field leakage caused by seawater eddy effects.

[0036] Specifically, the transmitting coil 1 is embedded inside the transmitting shielding structure. The transmitting shielding structure consists of three layers: from the inside out (or from the center of the magnetic field outwards), a central nanocrystalline shielding layer 11, an aluminum foil shielding layer 12, and a rear nanocrystalline shielding layer 13. The aluminum foil shielding layer 12 and the rear nanocrystalline shielding layer 13 together form a flat, disk-shaped base structure. The central nanocrystalline shielding layer 11, acting as a protruding pillar or platform, is positioned at the geometric center of the disk structure. This protrusion is precisely embedded in the hollow region of the racetrack-shaped transmitting coil 1, achieving direct and efficient shielding against the strongest magnetic field at the coil center. The nanocrystalline material has high permeability, effectively guiding and confining magnetic field lines; the aluminum foil layer, as an electrical shielding layer, can block high-frequency electric fields and generate reverse eddy currents to offset some of the external magnetic field. The combination of these three elements achieves a dual effect of magnetic field concentration and eddy current suppression.

[0037] Similarly, the receiving coil 2 is embedded in the receiving shielding structure. The receiving shielding structure also comprises three layers: a central nanocrystalline shielding layer 21, an aluminum foil shielding layer 22, and a rear nanocrystalline shielding layer 23. The aluminum foil shielding layer 22 and the rear nanocrystalline shielding layer 23 form a square disk structure to accommodate the common square housing of receiving devices. The central nanocrystalline shielding layer 21 is also protruding from the center of the square disk and embedded inside the receiving coil 2, with the same shielding principle as the transmitting end.

[0038] In terms of circuit architecture, as shown in the attached document. Figure 4 As shown, the transmitting unit integrates a high-frequency inverter module, a transmitting-end resonant compensation network, and a magnetic coupling mechanism (Lp). The receiving unit integrates a receiving section (Ls) with a magnetic coupling mechanism, a receiving-end resonant compensation network, and a rectifier and filter circuit. The transmitting-end resonant compensation network, the magnetic coupling mechanism (Lp, Ls), and the receiving-end resonant compensation network together constitute an LCC-S type compensation network. This network topology is beneficial for achieving near-constant current characteristics of the system output when the transmission distance on the seabed varies, thus improving system stability.

[0039] Example 2 During system operation, the high-frequency inverter module of the transmitting unit converts the DC input voltage into a high-frequency AC square wave. This high-frequency excitation is then fed into the transmitting end resonant compensation network. Details are as follows: S1: Based on Kirchhoff's laws and the fundamental wave equivalent method, an equivalent circuit model of a magnetically shielded system for wireless power transmission in the presence of metallic materials is established. The equivalent circuit model includes a high-frequency inverter module, an LCC-S compensation network, and a rectifier filter circuit. S2: Based on the established equivalent circuit model, split-side compensation is adopted to perform split-side resonance on the transmitter resonance compensation network and receiver resonance compensation network of the LCC-S compensation network. S3: Under the condition that the transmitting end resonant compensation network and the receiving end resonant compensation network are resonant on both sides, calculate the transmission efficiency of the equivalent circuit model. S4: Based on the transmission efficiency of the equivalent circuit model, determine the necessity of electromagnetic shielding design for the wireless power transmission magnetic shielding system.

[0040] Specifically, in S1, based on Kirchhoff's laws and the fundamental wave equivalence method, an equivalent circuit model of the wireless power transmission magnetic shielding system in the presence of metallic materials is established. The equivalent circuit model includes a high-frequency inverter module, an LCC-S compensation network, and a rectifier filter circuit.

[0041] High-frequency inverter technology is employed, and a full-bridge topology with large power capacity and excellent output characteristics is selected as the main inverter circuit. The high-frequency inverter module is a full-bridge inverter circuit composed of switching transistors Q1, Q2, Q3, and Q4. The input terminal of the full-bridge inverter circuit is connected to a DC power supply U. in The switching transistors Q1 and Q4 of the full-bridge inverter circuit are connected to the compensation network.

[0042] The compensation network structure is LCC-S type, where the transmitter uses an LCC topology and the receiver uses a series compensation topology design. f Transmitter compensation inductor L f One end is connected to the switching transistor Q1 of the high-frequency inverter module, and the other end is connected to the capacitor. One end is connected to the capacitor. The other end is connected in sequence to inductor Lp and the line equivalent resistance. Equivalent resistance of eddy current loss at the transmitter It is then connected to the switch Q4 of the primary-side resonant compensation network, and the inductor L f and capacitor A capacitor C is also connected between them. f One end of the capacitor C f The other end is connected to the switching transistor Q4; inductors Lp and Ls form a magnetic coupling mechanism, with inductor Lp being the transmitting coil inductance and inductor Ls being the receiving coil inductance; the inductor Ls of the magnetic coupling mechanism is also connected to the receiving end resonant compensation network.

[0043] The receiver resonance compensation network includes capacitors. ,capacitance One end is connected to one end of the inductor Ls, and the capacitor The other end is connected to the rectifier and filter circuit. The rectifier and filter circuit includes a rectifier bridge composed of diodes D1, D2, D3, and D4. Diodes D1 and D3 are connected in series, and diodes D2 and D4 are connected in series and then in parallel with capacitor Co. Diode D1 is connected to the capacitor of the receiver resonant compensation network. The connection is made so that the inductor Ls passes through the equivalent resistance of the line in sequence. and the equivalent resistance of eddy current loss at the receiving end Connected to diode D4, capacitor Co is also connected to the load. in parallel.

[0044] Furthermore, based on Kirchhoff's laws and the fundamental wave equivalence method, an equivalent circuit model is established, which equates the seawater eddy effect to an additional resistance introduced into the system. The DC power supply U at the inverter output port ab can be... in And the full-bridge inverter circuit, which is equivalent to the fundamental AC voltage source V ab At the same time, the rectifier filter circuit and load at the rear end of the rectifier input port CD are... Equivalent to R eq It should be noted that the marine application environment is complex and variable, with various uncertain interference variables. Therefore, this invention specifically incorporates the impact of seawater on the underwater wireless power transmission system during the design process. The core impact of seawater on the underwater wireless power transmission system is the eddy current effect. Based on this mechanism, the equivalent circuit model of the underwater wireless power transmission system considering eddy current losses is as follows: Figure 2 As shown.

[0045] The Kirchhoff voltage equations for the equivalent circuit model are as follows:

[0046]

[0047] in, The DC resistance of the transmitting coil, Let Lr be the equivalent resistance of the eddy current loss of the inductor. The imaginary unit represents the phase difference between voltage and current; Angular frequency; The self-inductance of the transmitting coil; For the transmitting coil and The first compensation capacitor connected in series, This represents the current in the transmitting coil. The compensating inductance for the transmitting coil, For the input current, Let be the magnetic field coupling coefficient between the transmitting unit and the receiving unit. For the receiving end current, This refers to the input voltage. For load resistance, The inherent resistance of the receiving coil. The equivalent resistance for eddy current losses at the receiving end is... This is the third compensation capacitor at the receiving end.

[0048] Specifically, in S2, to obtain optimal transmission performance, split-side compensation is adopted, that is, the compensation networks on the transmitting and receiving sides are made to reach a resonant state separately. The conditions for split-side resonance of the transmitting and receiving resonant compensation networks are as follows:

[0049] in, For the transmitting coil and Together they form the second compensation capacitor of the resonant compensation circuit. For the self-inductance of the receiving coil, This is the compensation capacitor for the receiving coil.

[0050] Specifically, in S3, when the system satisfies the aforementioned split-side resonance condition, the circuit equations can be greatly simplified. At this point, the system's transmission efficiency η can be derived into a relatively concise expression:

[0051] in, This represents the transmission efficiency of the equivalent circuit model.

[0052] Specifically, in S4, the derivation results show that the system efficiency is directly related to the mutual inductance M of the transmitting and receiving coils, the resonant angular frequency, and the loss resistance of each component. Furthermore, seawater eddy current losses affect the upper limit of transmission efficiency by altering the equivalent internal resistance characteristics. This derivation process allows for optimization of the shielding structure, selection of the operating frequency, and coil parameters during the design phase, thereby achieving the highest possible wireless power transmission efficiency in complex seawater environments. It provides solid theoretical support for subsequent system parameter optimization, loss suppression, and efficiency improvement designs. Simultaneously, by quantifying the impact of eddy current effects, it lays the theoretical foundation for the engineering implementation of underwater wireless power transmission systems.

[0053] In a preferred embodiment, based on the theory of electrical energy transfer in free space and the theory of field-circuit coupling, a circuit theory model is established when metallic materials are present. In this case, the wireless power transfer system can still transfer energy. When the metal plates are present on both sides of the coupling mechanism, the equivalent circuit model of wireless power transfer is as follows: Figure 6 As shown.

[0054] According to Kirchhoff's laws, the following equation can be derived:

[0055] Z1 is the equivalent impedance of the transmitter metal, R1 is the equivalent resistance of the transmitter metal, L1 is the equivalent inductance of the transmitter metal, I1 is the loop current of the transmitter metal equivalent circuit, M1 is the mutual inductance between the transmitter metal equivalent circuit and the transmitting coil, and I... p Zp is the transmitter current, Zs is the transmitter total impedance, Zs is the receiver total impedance, Z2 is the receiver metal equivalent impedance, R2 is the receiver metal equivalent resistance, L2 is the receiver metal equivalent inductance, M2 is the mutual inductance between the receiver metal equivalent circuit and the receiver coil, and I2 is the receiver metal equivalent circuit loop current.

[0056] The efficiency expression is derived as follows:

[0057] For underwater wireless power transmission systems, the inductance of the coil changes when metallic materials are present around the system, causing a shift in the system's operating frequency. Since the system's transmission characteristics are highly sensitive to the resonant frequency, changes in the resonant frequency affect the transmission performance. Therefore, shielding is necessary.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A magnetically coupled resonant wireless power transfer magnetic shielding system for underwater applications, characterized in that, It includes a transmitting unit and a receiving unit. The transmitting unit includes a transmitting coil (1) and a transmitting shielding structure. The receiving unit includes a receiving coil (2) and a receiving shielding structure. The transmitting coil (1) and the receiving coil (2) are coupled by a spatial magnetic field. The transmitting shielding structure and the receiving shielding structure are multi-layer shielding structures.

2. The underwater magnetically coupled resonant wireless power transfer magnetic shielding system according to claim 1, characterized in that, The transmitting coil (1) is a circular coil, and the receiving coil (2) is a racetrack-shaped coil.

3. The underwater magnetically coupled resonant wireless power transfer magnetic shielding system according to claim 2, characterized in that, The transmitting coil (1) is embedded in the transmitting shielding structure, which includes: a central nanocrystalline shielding layer (11), an aluminum foil shielding layer (12), and a rear nanocrystalline shielding layer (13). The aluminum foil shielding layer (12) and the rear nanocrystalline shielding layer (13) form a disk structure. The central nanocrystalline shielding layer (11) is protruding from the center of the disk structure and embedded in the transmitting coil (1).

4. The underwater magnetically coupled resonant wireless power transfer magnetic shielding system according to claim 2, characterized in that, The receiving coil (2) is embedded in the receiving shielding structure, which includes: a receiving center nanocrystalline shielding layer (21), a receiving aluminum foil shielding layer (22), and a receiving back nanocrystalline shielding layer (23). The receiving aluminum foil shielding layer (22) and the receiving back nanocrystalline shielding layer (23) form a square disk structure. The receiving center nanocrystalline shielding layer (21) is protruding from the center of the square disk structure and embedded in the receiving coil (2).

5. The underwater magnetically coupled resonant wireless power transfer magnetic shielding system according to claim 1, characterized in that, The transmitting and receiving units incorporate a high-frequency inverter module, a transmitting-end resonant compensation network, a magnetic coupling mechanism, a receiving-end resonant compensation network, and a rectifier filter circuit. The transmitting-end resonant compensation network and the receiving-end resonant compensation network adopt the LCC-S compensation network.

6. A method for magnetic shielding of underwater magnetically coupled resonant wireless power transfer, based on the underwater magnetically coupled resonant wireless power transfer magnetic shielding system described in claim 5, characterized in that, Includes the following steps: Based on Kirchhoff's laws and the fundamental wave equivalence method, an equivalent circuit model of a magnetically shielded system for wireless power transmission in the presence of metallic materials is established. This equivalent circuit model includes an equivalent voltage source. V ab LCC-S compensation network, equivalent load R eq Equivalent circuits of the transmitting and receiving metal plates; Based on the established equivalent circuit model, split-side compensation is adopted to perform split-side resonance on the transmitter resonance compensation network and the receiver resonance compensation network of the LCC-S compensation network. Calculate the transmission efficiency of the equivalent circuit model under the condition that the transmitting end resonant compensation network and the receiving end resonant compensation network are resonant on both sides. Based on the transmission efficiency of the equivalent circuit model, the necessity of electromagnetic shielding design for the wireless power transmission magnetic shielding system is determined.

7. The underwater magnetic coupling resonant wireless power transfer magnetic shielding method according to claim 6, characterized in that, The equivalent circuit model treats the seawater eddy effect as an introduced additional resistance.

8. The underwater magnetic coupling resonant wireless power transfer magnetic shielding method according to claim 7, characterized in that, In the step of establishing an equivalent circuit model of a magnetically shielded wireless power transmission system with metallic materials based on Kirchhoff's laws and the fundamental wave equivalence method, the Kirchhoff voltage equation of the equivalent circuit model is as follows: in, The DC resistance of the transmitting coil, Let Lr be the equivalent resistance of the eddy current loss of the inductor. The imaginary unit; Angular frequency; The self-inductance of the transmitting coil; For the transmitting coil and The first compensation capacitor connected in series, This represents the current in the transmitting coil. The compensating inductance for the transmitting coil, For the input current, Let be the magnetic field coupling coefficient between the transmitting unit and the receiving unit. For the receiving end current, This refers to the input voltage. For load resistance, The inherent resistance of the receiving coil. The equivalent resistance for eddy current losses at the receiving end is... This is the third compensation capacitor at the receiving end.

9. The underwater magnetically coupled resonant wireless power transfer magnetic shielding system according to claim 8, characterized in that, In the step of performing split-side resonance on the transmitter and receiver resonance compensation networks of the LCC-S compensation network based on the established equivalent circuit model and using split-side compensation, the conditions for performing split-side resonance on the transmitter and receiver resonance compensation networks are as follows: in, For the transmitting coil and Together they form the second compensation capacitor of the resonant compensation circuit. For the self-inductance of the receiving coil, This is the compensation capacitor for the receiving coil.

10. The underwater magnetically coupled resonant wireless power transfer magnetic shielding system according to claim 9, characterized in that, Under the condition that the transmitting-end resonant compensation network and the receiving-end resonant compensation network are in separate-side resonance, the transmission efficiency of the equivalent circuit model is calculated as follows: in, This represents the transmission efficiency of the equivalent circuit model.

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