Electromagnetic shielding structure giving consideration to efficiency of satellite-borne wireless power transmission device

Abstract

The invention discloses an electromagnetic shielding structure giving consideration to the efficiency of a satellite-borne wireless power transmission device. The electromagnetic shielding structure comprises a magnetic coupling structure and a shielding structure, wherein the magnetic coupling structure comprises a primary coil and a secondary coil; the wheel-type magnetic core structure comprises an upper wheel-type magnetic core structure which is arranged close to the upper side of the primary side coil and a lower wheel-type magnetic core structure which is arranged close to the lower side of the secondary side coil; the metal shielding structure comprises an upper metal shielding shell arranged above the upper wheel type magnetic core structure and a lower metal shielding shell arranged below the lower wheel type magnetic core structure; and the thin-strip passive coil shielding structure comprises a plurality of auxiliary coils which are arranged on the lateral periphery of the magnetic coupling mechanism. According to the electromagnetic shielding structure, the electric energy transmission efficiency is guaranteed, meanwhile, leakage magnetic field electromagnetic interference suppression and energy transmission structure quality are considered, efficient operation of a satellite-borne wireless electric energy transmission system is guaranteed, and meanwhile normal work of other equipment is not interfered.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic shielding, and in particular to an electromagnetic shielding structure that takes into account the efficiency of a satellite-borne wireless power transmission device. Background Art

[0002] With the rapid development of aerospace technology, wireless power transfer (WPT) technology is increasingly being used in satellite systems for applications such as powering extravehicular equipment and recharging deployable structures. Its contactless energy transfer effectively addresses the wear, aging, and spatial layout limitations of traditional cable connections. However, the onboard environment places extremely stringent electromagnetic compatibility (EMC) requirements: the internal magnetic field of the satellite must be strictly controlled below 50μT, and sensitive equipment such as attitude control sensors and high-precision communication payloads are susceptible to interference from leakage magnetic fields.

[0003] Traditional electromagnetic shielding methods face technical bottlenecks in spaceborne applications.

[0004] Although ferrite cores can improve coupling efficiency by providing a low magnetic resistance path (for example, the coupling coefficient reaches 0.47 under the SS compensation topology), their effect on suppressing edge leakage is limited (the leakage magnetic field peak reaches 600μT at 120μs). Although aluminum shielding can offset leakage through eddy current effects, eddy current losses cause the system efficiency to drop by 5-10%, and the additional mass is increased (the density of the aluminum plate is 2.7g / cm 3 ); The active coil shielding solution requires an independent power supply module, which significantly increases the complexity and power consumption burden of the satellite energy system.

[0005] Space and weight constraints: Space-based equipment is compact and mass-sensitive. Existing combined shielding solutions (such as a multilayer ferrite + aluminum plate structure) result in a volume expansion of over 30%. While thickening the magnetic core improves shielding effectiveness, it also increases mass, violating the principle of lightweight satellite design. Furthermore, if the auxiliary coil shielding structure is not integrated and optimized with the magnetic core, it will occupy valuable extravehicular installation space. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide an electromagnetic shielding structure that takes into account the efficiency of the satellite-borne wireless power transmission device. While ensuring the efficiency of power transmission, the electromagnetic shielding structure takes into account the suppression of electromagnetic interference in the leakage magnetic field and the quality of the energy transmission structure, ensuring the efficient operation of the satellite-borne wireless power transmission system without interfering with the normal operation of other equipment.

[0007] The object of the present invention is achieved through the following technical solutions: an electromagnetic shielding structure that takes into account the efficiency of a satellite-borne wireless power transmission device, comprising: a magnetic coupling structure, a wheel-shaped magnetic core structure, a metal shielding structure, and a thin-strip passive coil shielding structure;

[0008] The magnetic coupling structure includes a primary coil as a wireless power transmitting end and a secondary coil as a wireless power receiving end;

[0009] The wheel-shaped magnetic core structure includes an upper wheel-shaped magnetic core structure installed adjacent to the upper side of the primary coil, and a lower wheel-shaped magnetic core structure installed adjacent to the lower side of the secondary coil;

[0010] The metal shielding structure includes an upper metal shielding shell arranged above the upper wheel-shaped magnetic core structure, and a lower metal shielding shell arranged below the lower wheel-shaped magnetic core structure;

[0011] The thin-strip passive coil shielding structure includes a plurality of auxiliary coils installed on the lateral periphery of the magnetic coupling mechanism, and the plane where the auxiliary coils are located is perpendicular to the plane where the primary coil and the secondary coil are located.

[0012] The primary coil is fixed to the upper wheel-shaped magnetic core structure through an insulating material, the upper wheel-shaped magnetic core structure is fixed to the upper metal shielding shell through an insulating material, the upper metal shielding shell is fixed to the satellite shell through an insulating material, and the power supply module inside the satellite is electrically connected to the primary coil (through a conductive wire);

[0013] The secondary coil is fixed to the lower wheel-shaped magnetic core structure via an insulating material, the lower wheel-shaped magnetic core structure is fixed to the lower metal shielding shell via an insulating material, the lower metal shielding shell is fixed to the outer shell of the electrical load via an insulating material, and the secondary coil is electrically connected to the electrical load via a rectifier; specifically, the secondary coil is connected to the rectifier in the outer shell of the electrical load via a wire, and the rectifier is electrically connected to the power supply terminal of the electrical load;

[0014] The power supply module inside the satellite includes a DC power supply module, an inverter and a power filter circuit. The output end of the DC power supply module converts DC power into AC power through the inverter, and then injects it into the primary coil through the power filter circuit; the changing current induces a changing magnetic field around the primary coil, and the magnetic field generates an induced current in the secondary coil, which is converted into DC power by a rectifier to power the electrical load, thereby realizing wireless power transmission.

[0015] The wheel-shaped shielding structure material is ferrite material, and its outer diameter should be larger than the radius of the primary and secondary coils. The thickness is adjusted based on the comprehensive consideration of magnetic shielding effectiveness, structural weight and transmission efficiency, and the typical value is 10mm.

[0016] The metal structure is an aluminum metal structure. The increase in the thickness of the aluminum metal shielding structure has little effect on the magnetic field distribution, and the typical value is 5mm. The upper and lower aluminum metal shielding structures are equidistant from the wheel-shaped magnetic shielding structure, and the typical value is 1mm.

[0017] The thin-ribbon passive coil is made of a Bernal multilayer stack of graphene, with a rectangular cross-section and a thickness much smaller than its width. The shielding structure's shielding efficiency-to-weight ratio is primarily influenced by the number of layers and stacked thin-ribbon passive coils. (For example, a single coil with 100 layers stacked at 60kHz exhibits a SEMR 13.6 times that of a copper shield of the same thickness, significantly reducing weight and improving shielding efficiency.)

[0018] Graphene-based thin-ribbon coils are strong and flexible, and their flat coil structure increases the heat dissipation area. Shielding structures are typically installed at the extension of the primary and secondary coils or at the outer edge of the wheel-shaped core, connected via insulating material.

[0019] Metal shielding structure (axial suppression): Primarily made of high-conductivity metal (such as aluminum), it is placed outside the magnetic core. Its operating principle is based on the eddy current effect. When a changing leakage magnetic field (especially the axial component) passes through the metal layer, Faraday's law of electromagnetic induction induces eddy currents within the metal. These eddy currents generate a secondary magnetic field in the opposite direction of the original changing magnetic field, effectively offsetting some of the axial leakage magnetic field and reducing its interference with the satellite's outer space or adjacent compartments.

[0020] Wheel-shaped core structure (axial suppression and efficiency improvement): Made of high-permeability ferrite material, its core features are radially extending magnetic strips, central circular connections, and integral circular connections at the outer ends. Its working principle is to provide a low-reluctance path for the system's main magnetic flux. This structure more effectively confines the magnetic field generated by the coil to the internal path of the core, guiding the magnetic lines of force to efficiently couple between the transmitter and receiver, reducing magnetic flux leakage above and below the coil (axially). At the same time, by optimizing the magnetic circuit, the coupling coefficient between the coils can be significantly improved, thereby improving the system's wireless power transmission efficiency.

[0021] Thin-strip passive coil shielding structure (lateral suppression): It includes multiple auxiliary coils, which are wound by flexible auxiliary wires with rectangular cross-sections, and the thickness of the flexible auxiliary wires is greater than the width. The flexible auxiliary wires are made of graphene and are obtained by stacking multiple layers of graphene using the Berna method; multiple auxiliary coils are installed on the lateral periphery of the main coil system, and their planes are perpendicular to the plane of the main coil. Its working principle is to use the high conductivity characteristics of multilayer graphene to achieve strong reflection loss SE R , according to the formula SE R =168-10lg(f / σ), and the extremely high conductivity σ is achieved by multi-layer stacking of graphene, resulting in a significant reflection effect; at the same time, the thickness and unique microstructure of graphene are used to achieve efficient absorption loss (SE A ), according to the formula Through a triple mechanism of multiple reflections and scattering within the material, dielectric loss (polarization relaxation) caused by functional group defects, and electron migration collisions (ohmic losses) within the conductive network, coupled lateral magnetic flux leakage energy is continuously converted into heat and dissipated. This composite shielding mechanism simultaneously suppresses magnetic flux leakage reflections and converts energy into absorption without the need for external power, achieving highly effective suppression of lateral electromagnetic leakage.

[0022] Aiming at the special requirements of spaceborne applications, the present invention proposes to use the shielding effectiveness to mass ratio to quantify the shielding effectiveness and weight of the shielding structure. The expression is: Graphene density ≈2.2g / cm 3 , the thickness of the single layer is ≈0.34nm, and the surface density of the single layer is ≈0.00075g / cm 3 , N-level density: ρ N ≈0.00075×N g / cm 3 Therefore, the shielding effect of N-layer stacked graphene shielding coil is better than

[0023] The screen efficiency-to-mass ratio (SEMR) shows an inverted U-shaped three-stage change curve: (1) Ultra-thin stage (1-100 layers, thickness <34nm), the increase in the number of layers significantly improves the conductive network, the skin effect has not yet dominated, the unit mass efficiency is the highest, and SERM rises sharply; (2) Medium thickness (100 layers-1μm, 34nm-34μm), the skin depth is limited, the contribution of additional thickness decreases, the mass increases faster, and SERM decreases slowly; thick layer stage (>1μm), the thickness far exceeds the skin depth, the eddy current is saturated, the mass becomes the main cost, and SERM continues to decline.

[0024] The present invention achieves the following beneficial effects: highly efficient synergistic shielding: axial magnetic field leakage is effectively suppressed through the eddy current cancellation principle of the metal shielding structure; lateral magnetic field leakage is effectively suppressed through the active magnetic field cancellation principle of the thin-strip passive coil shielding structure. These two elements, combined with the flux guidance of the wheel-shaped magnetic core structure, achieve all-round suppression of spatial magnetic field leakage.

[0025] Guaranteed transmission efficiency: The wheel-shaped magnetic core structure is the core component, and its optimized magnetic circuit design (radial magnetic strips, center connection, and outer end ring connection) significantly improves the coupling coefficient between the primary and secondary coils (can be increased to above 0.54), thereby ensuring efficient wireless power transmission of the system.

[0026] Meeting stringent satellite-borne requirements: The composite shielding structure works synergistically to significantly reduce the leakage magnetic field strength in critical areas (such as within a specific range from the coil) to a level close to or meeting the stringent satellite-borne limit of 50μT.

[0027] Adapting to onboard constraints: The structure is compact and volume expansion is reduced through optimized integration; the passive design is mainly adopted (especially the thin-strip passive coil shielding, which is 80-90% lighter than the traditional winding coil), avoiding the addition of additional power supply modules, meeting the requirements of lightweight and low power consumption of satellites. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the present invention;

[0029] Figure 2 This is a structural diagram of the auxiliary coil. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0031] like Figure 1 As shown, an electromagnetic shielding structure that takes into account the efficiency of a satellite-borne wireless power transmission device includes the following coaxially arranged components:

[0032] Magnetic coupling mechanism: Consists of a circular primary coil 1 and a circular secondary coil 2. Both coils have the same radius, number of turns, and turn spacing, and are placed parallel to each other. The spacing is determined by the system design. The primary and secondary coils act as a wireless power transmission device, with the primary coil acting as the wireless power transmitter and the secondary coil acting as the wireless power receiver.

[0033] Cartwheel-shaped core structure: This structure is made of ferrite material. An upper wheel-shaped core structure 3 is mounted immediately above the primary coil 1, and a lower wheel-shaped core structure 4 is mounted immediately below the secondary coil 2. This core structure, made of ferrite material, features: a) multiple magnetic strips radiating outward from a central point; b) all strips are interconnected by a circular structure at the center; and c) the outer ends of all strips are connected by a single, circular ring structure. The outer diameter of the core is larger than the outer diameter of the coil it covers.

[0034] Specifically, the upper wheel-shaped magnetic core structure 3 and the lower wheel-shaped magnetic core structure 4 are made of ferrite material and have the same structure; the same structure includes a concentric ring structure 8 and a circular structure 9, and the circular structure is located inside the ring structure;

[0035] The annular structure and the circular structure are connected by a plurality of magnetic strips 10; each magnetic strip extends radially from the circular structure to the annular structure along the radius direction of the annular structure.

[0036] Metal shielding structure: This structure is made of aluminum. An upper metal shielding shell 5 is mounted on the outer sides of the wheel-shaped core structure, above the upper wheel-shaped core structure 3, and a lower metal shielding shell 6 is mounted below the lower wheel-shaped core structure 4. In this embodiment, the shielding shell is preferably made of aluminum or an aluminum alloy in the shape of an oblate cylinder, with a radius that matches or slightly exceeds the outer diameter of the wheel-shaped core. A certain distance (e.g., 1 mm) is maintained between the upper and lower shielding shells and their adjacent wheel-shaped core structures.

[0037] In an embodiment of the present application, the primary coil 1 is fixed to the upper wheel-shaped magnetic core structure 3 by an insulating material, the upper wheel-shaped magnetic core structure 3 is fixed to the upper metal shielding shell 5 by an insulating material, the upper metal shielding shell 5 is fixed to the satellite shell by an insulating material, and the power supply module inside the satellite is electrically connected to the primary coil 1;

[0038] The secondary coil 2 is fixed to the lower wheel-shaped magnetic core structure 4 through insulating material, the lower wheel-shaped magnetic core structure 4 is fixed to the lower metal shielding shell 6 through insulating material, the lower metal shielding shell 6 is fixed to the electrical load casing through insulating material, and the secondary coil 2 is electrically connected to the electrical load through a rectifier.

[0039] The power supply module inside the satellite includes a DC power supply module, an inverter and a power filter circuit. The output end of the DC power supply module converts DC power into AC power through the inverter, and then injects it into the primary coil 1 through the power filter circuit; the changing current induces a changing magnetic field around the primary coil, and the magnetic field generates an induced current in the secondary coil 2, which is converted into DC power by the rectifier to power the electrical load, thereby realizing wireless power transmission.

[0040] In the embodiments of the present application, Figure 2 As shown, the thin-strip passive coil shielding structure includes multiple auxiliary coils, each wound from a flexible auxiliary wire with a rectangular cross-section, wherein the thickness of the flexible auxiliary wire is greater than its width. The flexible auxiliary wire is made of graphene and is obtained by stacking multiple layers of graphene using the Berna method. The number of layers can be modified based on the shielding effect-to-mass ratio to flexibly meet the requirements for magnetic coupling and mechanism weight and leakage magnetic shielding performance in satellite-borne equipment. The number of coil turns is typically 3 to 5. The number of coils can be flexibly increased or decreased based on the shielding requirements for lateral leakage magnetic field (typical value is 4-6). The installation position is located at the outer edge of the magnetic coupling mechanism or the outer edge of the wheel-shaped magnetic core structure.

[0041] Table 1 compares the shield-to-mass ratio (SMER) of a 100-layer Berna stacked graphene ribbon passive shielding coil and a copper passive coil of the same thickness:

[0042] Table 1

[0043]

[0044] At both low frequencies (60kHz) and high frequencies (100MHz), its graphene-based SMER outperforms copper-based passive shielding coils, greatly reducing weight while ensuring shielding effectiveness, making it suitable for special satellite-borne conditions.

[0045] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. An electromagnetic shielding structure that takes into account the efficiency of a satellite-borne wireless power transmission device, characterized by: It includes a magnetic coupling structure, a wheel-shaped magnetic core structure, a metal shielding structure and a thin-strip passive coil shielding structure; The magnetic coupling structure comprises a primary coil (1) serving as a wireless power transmitting end and a secondary coil (2) serving as a wireless power receiving end; The wheel-shaped magnetic core structure comprises an upper wheel-shaped magnetic core structure (3) installed adjacent to the upper side of the primary coil (1), and a lower wheel-shaped magnetic core structure (4) installed adjacent to the lower side of the secondary coil (2); The metal shielding structure comprises an upper metal shielding shell (5) arranged above the upper wheel-shaped magnetic core structure (3), and a lower metal shielding shell (6) arranged below the lower wheel-shaped magnetic core structure (4); The thin-strip passive coil shielding structure comprises a plurality of auxiliary coils (7) mounted on the lateral periphery of the magnetic coupling mechanism, wherein the plane where the auxiliary coils (7) are located is perpendicular to the plane where the primary coil (1) and the secondary coil (2) are located.

2. The electromagnetic shielding structure according to claim 1, wherein: The primary coil (1) is fixed to the upper wheel-shaped magnetic core structure (3) via an insulating material, the upper wheel-shaped magnetic core structure (3) is fixed to the upper metal shielding shell (5) via an insulating material, the upper metal shielding shell (5) is fixed to the satellite shell via an insulating material, and the power supply module inside the satellite is electrically connected to the primary coil (1); The secondary coil (2) is fixed to the lower wheel-shaped magnetic core structure (4) through an insulating material, the lower wheel-shaped magnetic core structure (4) is fixed to the lower metal shielding shell (6) through an insulating material, the lower metal shielding shell (6) is fixed to the electrical load housing through an insulating material, and the secondary coil (2) is electrically connected to the electrical load through a rectifier.

3. The electromagnetic shielding structure according to claim 2, wherein: The power supply module inside the satellite includes a DC power supply module, an inverter and a power filter circuit. The output end of the DC power supply module converts DC power into AC power through the inverter, and then injects the AC power into the primary coil (1) through the power filter circuit; the changing current induces a changing magnetic field around the primary coil, and the magnetic field generates an induced current in the secondary coil (2), which is converted into DC power by a rectifier to power the electrical load, thereby realizing wireless power transmission.

4. The electromagnetic shielding structure according to claim 1, wherein: The primary coil (1) and the secondary coil (2) are parallel to each other and aligned vertically.

5. The electromagnetic shielding structure according to claim 1, wherein: The primary coil (1) and the secondary coil (2) are both circular coils, and their radius, number of turns, and turn spacing are all exactly the same.

6. The electromagnetic shielding structure according to claim 1, wherein: The upper wheel-shaped magnetic core structure (3) and the lower wheel-shaped magnetic core structure (4) are made of ferrite material and have the same structure; the same structure includes a concentric ring structure (8) and a circular structure (9), and the circular structure is located inside the ring structure; The annular structure and the circular structure are connected via a plurality of magnetic strips (10); each magnetic strip extends radially from the circular structure to the annular structure along the radius direction of the annular structure.

7. The electromagnetic shielding structure according to claim 1, wherein: The auxiliary coil (7) is formed by winding a flexible auxiliary wire with a rectangular cross-section, and the thickness of the flexible auxiliary wire is greater than the width.

8. The electromagnetic shielding structure according to claim 7, which takes into account the efficiency of the satellite-borne wireless power transmission device, is characterized in that: The flexible auxiliary line is made of graphene and is obtained by stacking multiple layers of graphene using the Berna method.

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