A nanocrystalline magnetic conductor and a wireless charging device for drones

Abstract

This invention discloses a nanocrystalline magnetic conductor and a wireless charging device for drones. The nanocrystalline magnetic conductor is mainly composed of multiple stacked magnetic conductors A. Each magnetic conductor A consists of a first nanocrystalline flexible sheet stack structure and a protective film layer. The first nanocrystalline flexible sheet stack structure consists of six layers of nanocrystalline flexible sheets. The protective film layer is disposed on the upper and lower surfaces of the first nanocrystalline flexible sheet stack structure. This nanocrystalline magnetic conductor is lightweight and miniaturized, and the wireless charging device for drones disclosed in this invention can achieve high-efficiency wireless charging.

Description

Technical Field

[0001] This invention belongs to the field of wireless charging technology, specifically relating to a nanocrystalline magnetic conductor and a wireless charging device for drones. Background Technology

[0002] High-efficiency, lightweight, and miniaturized high-power wireless charging devices for drones are expected to solve the current problems of short flight range and frequent charging of drones (UAVs) in fields such as 3D map modeling, material transportation, data signal collection, and remote traffic monitoring.

[0003] A wireless charging system comprises a circuit and a magnetic coupling mechanism. The magnetic coupling mechanism includes a coupling coil and a magnetic conductor. The magnetic conductor primarily enhances magnetic flux, reduces magnetic leakage, and isolates unwanted electromagnetic waves. In high-power wireless charging magnetic coupling mechanisms, magnetic conductors are used to achieve long-distance, high-efficiency wireless charging. However, the addition of a magnetic conductor often increases the size and weight of the magnetic coupling mechanism. Previously, conventional magnetic conductors were made of high-permeability ferrite, which has low saturation magnetic induction, making it difficult to balance high efficiency and lightweight miniaturization in drone wireless charging systems. In contrast, nanocrystalline soft magnetic materials combine high saturation magnetic induction with low high-frequency loss, making them ideal magnetic conductors for high-efficiency, lightweight, and miniaturized drone wireless charging.

[0004] Patent publication number KR102457200B1 discloses a wireless charging device for drones. The device features a solenoid-type transmitter and receiver. When the drone lands to charge, the solenoid receiver is inserted into the groove of the transmitter for energy transfer. This device is characterized by its simple structure and small size. However, it uses ferrite as the magnetic conductor, which is fragile, and the drone's landing deviation makes it difficult to apply practically in the field.

[0005] Patent application CN117238650A discloses an iron-based nanocrystalline magnetic conductor, its preparation method, and its application. The preparation method includes the following steps: continuously heat-treating an iron-based amorphous ribbon and then cooling it to obtain an iron-based nanocrystalline ribbon; adhering double-sided adhesive to one or both sides of the heat-treated iron-based nanocrystalline ribbon and then fragmenting it to uniformly distribute multiple cracks, which divide the iron-based nanocrystalline ribbon into multiple fragment units; cutting the fragmented iron-based nanocrystalline ribbon into multiple nanocrystalline strips; horizontally arranging the multiple nanocrystalline strips to form a single-layer nanocrystal; and orthogonally stacking the multiple single-layer nanocrystals to obtain the nanocrystalline magnetic conductor. The magnetic conductor disclosed in this patent has a large volume and cannot achieve high charging efficiency at high power.

[0006] With the widespread use of drones, the demand for wireless charging is becoming increasingly apparent. Due to the unique characteristics of drones, wireless charging devices must not only be highly efficient but also lightweight and miniaturized. Currently, in the application of nanocrystalline magnetic cores, a single-layer nanocrystalline magnetic core contains two layers of PET film, one layer of nanocrystalline ribbon, and two layers of double-sided adhesive. The thickness of the nanocrystalline ribbon ranges from 14-18 μm, while the thickness of the PET film is 75-80 μm. This results in a low volume and weight percentage for the nanocrystalline ribbon core, with a large amount of volume and weight occupied by the PET film, wasting resources. In practical applications, stacking single-layer nanocrystalline magnetic cores is necessary, further increasing weight and volume, thus limiting their application in drone wireless charging devices.

[0007] Therefore, for high-power wireless charging devices, it is necessary to optimize the number of layers and structure of nanocrystalline magnetic conductors in order to achieve high-efficiency, lightweight and miniaturized wireless charging devices. Summary of the Invention

[0008] This invention provides a nanocrystalline magnetic conductor that is lightweight and miniaturized. This invention also provides the application of the nanocrystalline magnetic conductor in a wireless charging device for drones, which enables high-efficiency wireless charging.

[0009] This invention provides a nanocrystalline magnetic conductor, which is mainly composed of multiple magnetic conductors A stacked together;

[0010] The magnetic conductor A is composed of a first nanocrystalline flexible sheet stacked structure and a protective film layer;

[0011] The first nanocrystalline flexible sheet stacked structure consists of six layers of nanocrystalline flexible sheets;

[0012] The protective film layer is disposed on the upper and lower surfaces of the first nanocrystalline flexible sheet stack structure.

[0013] Preferably, the nanocrystalline magnetic conductor further includes a magnetic conductor B, which is disposed on both sides of the magnetic conductor A to form an inverted trapezoidal stacked structure;

[0014] The magnetic conductor B is composed of a stacked structure of second nanocrystalline flexible sheets and a protective film layer;

[0015] The second nanocrystalline flexible sheet stacked structure consists of three layers of nanocrystalline flexible sheets;

[0016] The protective film layer is disposed on the upper and lower surfaces of the second nanocrystalline flexible sheet stack structure.

[0017] This invention employs an inverted trapezoidal structure, which effectively improves the efficiency of wireless charging devices for drones and addresses the issue of heat generation in the magnetic conductor during uniform application. By placing magnetic conductors B at both ends of magnetic conductor A, this invention helps improve the mutual coupling effect at the edges, thereby further enhancing wireless charging efficiency. The overall inverted trapezoidal structure helps to uniformly distribute the magnetic flux density within the magnetic conductor, resulting in a more uniform distribution of magnetic conductor losses and enabling longer-term application of wireless charging.

[0018] More preferably, the inverted trapezoidal stacking structure includes a wide upper part and a narrow lower part;

[0019] The upper part of the magnetic conductor A has a length of 42-44mm and a width of 20mm. On each side of the upper part of the magnetic conductor A, there is a magnetic conductor B with a length of 2.5mm and a width of 20mm.

[0020] The narrow lower magnetic conductor A has a length of 34-36 mm and a width of 20 mm. Magnetic conductors B, each 4 mm long and 20 mm wide, are disposed on both sides of the narrow lower magnetic conductor A. By providing magnetic conductors A and B of suitable dimensions, the mutual coupling effect at the edges of the nanocrystalline magnetic conductor provided by this invention is significantly improved, thereby further enhancing wireless charging efficiency.

[0021] Preferably, the nanocrystalline magnetic conductor is a rectangular cuboid structure formed by stacking two magnetic conductors A, each 42-44 mm long and 20 mm wide. This invention provides a suitable size for the magnetic conductor A and the number of stacked magnetic conductors A, enabling the nanocrystalline magnetic conductor provided by this invention to achieve high wireless charging efficiency in a relatively small volume.

[0022] Preferably, the nanocrystalline flexible sheet is obtained by combining broken nanocrystalline ultrathin strips and double-sided adhesive, wherein the thickness of the broken nanocrystalline ultrathin strips is 14-18 μm.

[0023] Compared to ferrites, nanocrystalline ribbons possess high saturation magnetism and high Curie temperature, and their fracturing process for fabricating magnetic conductors results in lower eddy current losses at high frequencies. Furthermore, the eddy current loss in nanocrystalline magnetic conductors is related to the thickness of the nanocrystalline ribbon; the thinner the ultrathin nanocrystalline ribbon, the lower the eddy current loss. Therefore, nanocrystalline magnetic conductors fabricated from ultrathin nanocrystalline ribbons are an effective choice for high-efficiency, lightweight, and miniaturized wireless charging devices for drones.

[0024] Preferably, the alloy composition of the nanocrystalline ultrathin ribbon is FeCuSiBNbP, FeCuSiBNbMn, or FeCuSiBNbMo.

[0025] Preferably, the protective film layer is a flexible PET film.

[0026] Preferably, the loss of the nanocrystalline magnetic conductor at 0.1T to 0.25T and 85kHz has a loss change rate of less than 3.4% within 20 to 80℃, and the loss at 0.1 to 0.25T and 150kHz has a loss change rate of less than 4.1% within 20 to 80℃.

[0027] The thermal stability of the magnetic conductor affects the application of wireless charging devices in various environments. The nanocrystalline magnetic conductor provided by this invention has good thermal stability, therefore it can be applied to a variety of different temperature environments. Consequently, the application scenarios of wireless charging devices using the nanocrystalline magnetic conductor provided by this invention are more diverse, and the differences in wireless charging performance are smaller when applied in various temperature environments.

[0028] On the other hand, the present invention provides a wireless charging device for drones, including a signal generator, a power amplifier, a transmitter supplement network, a nanocrystalline magnetic coupling structure, a receiver supplement network, a rectifier filter module, and a load;

[0029] The nanocrystalline magnetic coupling structure includes a circular coil and a nanocrystalline magnetic conductor. The nanocrystalline magnetic conductor is distributed in a cross shape on the lower and upper surfaces of the circular coil to form the transmitter and receiver, respectively.

[0030] The signal generator is electrically connected to the power amplifier, the power amplifier is electrically connected to the transmitter supplementary network, and the transmitter supplementary network is electrically connected to the transmitter of the nanocrystalline magnetic coupling structure.

[0031] The receiving end of the nanocrystalline magnetic coupling structure is electrically connected to the receiving end supplementary network, the receiving end supplementary network is electrically connected to the rectifier and filter module, and the rectifier and filter module is electrically connected to the load.

[0032] The nanocrystalline wireless charging device provided by this invention features a magnetic coupling mechanism composed of a nanocrystalline magnetic conductor and a circular coil. The circuitry comprises a signal generator, a power amplifier, a transmitter compensation network, a receiver compensation network, a rectifier and filter module, and a load. The wireless charging circuit, consisting of the signal generator and power amplifier, allows for quick and convenient adjustment of the wireless charging resonant frequency and power, facilitating performance testing of different wireless charging devices. The use of a cross-shaped magnetic conductor structure on the circular coil significantly enhances wireless charging efficiency, while the reduced magnetic conductor distribution meets the initial requirements for lightweight miniaturization.

[0033] Preferably, the circular coil is a hollow conductor, the inner diameter of the circular coil is 32mm, and the outer diameter of the circular coil is 74-76mm.

[0034] Preferably, the power range of the wireless charging device is 200-400W.

[0035] Preferably, the efficiency of the wireless charging device reaches 96% or higher.

[0036] Preferably, the volume of the magnetic conductors distributed in the wireless charging device is 8.3 cm³. 3 The following are products weighing less than 29.2g.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] The magnetic conductor A provided by the present invention has fewer protective films and more nanocrystalline flexible sheets, so that the nanocrystalline magnetic conductor formed by stacking magnetic conductors A can achieve lightweight miniaturization while ensuring high-efficiency wireless charging.

[0039] This invention achieves both lightweight and miniaturization by distributing nanocrystalline magnetic conductors in a star-shaped pattern on the upper and lower surfaces of a circular coil. Furthermore, through the magnetic field effect of the nanocrystalline magnetic conductors, the wireless charging device for drones provided by this invention achieves a wireless charging efficiency of over 96% at high power, while maintaining a size of only 8.3 cm². 3 Weighing less than 29.2g, it is more efficient, smaller, and lighter than comparable wireless charging devices for drones. Attached Figure Description

[0040] Figure 1 Error curves between simulation and actual test of surface magnetic flux density of the coupled coil provided for a specific embodiment of the present invention;

[0041] Figure 2 A diagram showing the relationship between coil mutual inductance and coil turns is provided for a specific embodiment of the present invention.

[0042] Figure 3 These are schematic diagrams of nanocrystalline magnetic conductors with different layer counts provided in Embodiments 1-2 and Comparative Examples 1-2 of the present invention, wherein: Figure 3 (a) is a schematic diagram of a single-layer nanocrystalline magnetic conductor. Figure 3 (b) is a schematic diagram of a three-layer nanocrystalline magnetic conductor. Figure 3 (c) is a schematic diagram of a six-layer nanocrystalline magnetic conductor;

[0043] Figure 4 This is an overall schematic diagram of a wireless charging device for drones provided in a specific embodiment of the present invention;

[0044] Figure 5 The following are simulation models and schematic diagrams of different structures of the multilayer magnetic conductors in the embodiments: Figure 5 (a) is a side view of the simulation model and magnetic conductor structure in Example 1. Figure 5 (b) is a side view of the simulation model and magnetic conductor structure in Example 2. Figure 5(c) is a side view of the simulation model and magnetic conductor structure in Comparative Example 1. Figure 5 (d) is a side view of the simulation model and magnetic conductor structure in Comparative Example 2.

[0045] Among them, 1-protective film layer; 2-double-sided adhesive layer; 3-fragmented nanocrystalline ultrathin strip; 4-nanocrystalline magnetic conductor; 5-circular coil; 6-signal generator; 7-power amplifier; 81-transmitter compensation capacitor; 82-receiver compensation capacitor; 9-rectifier filter module; 10-load resistor. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] This embodiment provides a low-loss nanocrystalline magnetic conductor and its wireless charging device for drones. The specific process is as follows:

[0049] (1) The nanocrystalline alloy used in this embodiment has Fe composition. 74 Si 13 B8Nb2Cu1Mn2 was used to prepare an 18μm thick precursor ultrathin strip using a single-roller rapid quenching method. After crystallization, nanocrystalline ultrathin strips were obtained, which were then combined with double-sided adhesive 2 and crushed to prepare a nanocrystalline flexible sheet composed of crushed nanocrystalline ultrathin strips 3 and double-sided adhesive 2. A magnetic conductor A was synthesized by bonding six layers of nanocrystalline flexible sheets together and coating them with an ultrathin flexible PET film. Figure 3 As shown in (c). Then, two magnetic conductors A, each 44mm long and 20mm wide, are stacked to form a rectangular cuboid structure for wireless charging, as shown. Figure 5 As shown in (a).

[0050] (2) Figure 5 As shown in (a), a copper coil with a wire diameter of 2 mm is made into a circular coil with an inner diameter of 32 mm and an outer diameter of 76 mm. A rectangular magnetic conductor is evenly distributed in a cross shape on the circular coil and combined to form a nanocrystalline magnetic coupling structure. The two are arranged opposite each other as the transmitter and receiver, respectively.

[0051] (3) Figure 4As shown, a low-loss nanocrystalline magnetic wireless charging device for drones is constructed by combining the transmitter and receiver prepared in step (2), a signal generator 6, a power amplifier 7, a transmitter compensation network including a transmitter compensation capacitor 81, a receiver compensation network including a receiver compensation capacitor 82, a rectifier filter module 9, and a load 10. The device has a power of 277W and a vertical distance of 88mm between the receiver and transmitter.

[0052] The loss of the nanocrystalline flexible sheet at different temperatures was tested using a MATS-2010SA instrument and a YFX2 / 12Q-GC box-type resistance furnace. The loss variation rate at 0.1T and 85kHz within the range of 20–80℃ was 3.34%, at 0.25T and 85kHz it was 2.88%, at 0.1T and 150kHz it was 3.32%, and at 0.25T and 150kHz it was 4.01%, indicating that this nanocrystalline flexible sheet has good thermal stability.

[0053] Simulation studies were conducted using simulation software, achieving a simulation efficiency of 96.22%. Actual testing of the magnetic coupling mechanism of the wireless charging device was performed using a digital oscilloscope and voltage / current probes. The efficiency of the nanocrystalline wireless charging device for drones was 96.26%, and the volume of the magnetic conductor was 8.026 cm³. 3 The weight is 29.166g. The wireless charging device in this embodiment has higher efficiency than Comparative Examples 1 and 2, and smaller weight and volume than Comparative Examples 1 and 2. The device basically achieves high efficiency and lightweight miniaturization.

[0054] Example 2

[0055] This embodiment demonstrates the fabrication of a low-loss nanocrystalline magnetic conductor and its wireless charging device for a drone. The specific process is as follows:

[0056] (1) The nanocrystalline alloy used in this embodiment has the composition of Fe. 74 Si 13 B8Nb2Cu1Mn2 was used to prepare an 18μm thick precursor ultrathin strip via a single-roller rapid quenching method. After crystallization, nanocrystalline ultrathin strips were obtained, which were then composited with double-sided adhesive and crushed to prepare nanocrystalline flexible sheets. Six layers of nanocrystalline flexible sheets were bonded together and coated with an ultrathin flexible PET film to synthesize a magnetic conductor A. Figure 3 As shown in (c), a magnetic conductor B is synthesized by bonding three layers of nanocrystalline flexible sheets and coating them with an ultrathin flexible PET film, as shown in [the diagram]. Figure 3As shown in (b). The magnetic conductors A and B are then designed as an inverted trapezoidal structure. The inverted trapezoidal structure is divided into upper and lower parts. The upper part consists of a 44mm long and 20mm wide magnetic conductor A, with magnetic conductors B, each 2.5mm long and 20mm wide, added to both ends of the upper half of conductor A. The lower part consists of a 36mm long and 20mm wide magnetic conductor A, with magnetic conductors B, each 4mm long and 20mm wide, added to both ends of the upper half of conductor A, as shown in (b). Figure 5 As shown in (b).

[0057] (2) Figure 5 As shown in (b), a copper coil with a wire diameter of 2 mm is fabricated into a circular coil with an inner diameter of 32 mm and an outer diameter of 76 mm. A rectangular parallelepiped magnetic conductor is evenly distributed in a star-shaped pattern on the circular coil, forming a nanocrystalline magnetic coupling structure. The two are arranged opposite each other as the transmitter and receiver, respectively.

[0058] (3) Figure 4 As shown, a low-loss nanocrystalline magnetic wireless charging device for UAVs is constructed by combining the transmitter and receiver prepared in step (2), a signal generator, a power amplifier, a transmitter compensation network, a receiver compensation network, a rectifier filter module, and a load. The device has a power of 273W, and the vertical distance between the receiver and the transmitter is 88mm.

[0059] Simulation studies were conducted using simulation software, achieving a simulation efficiency of 96.84%. The magnetic coupling mechanism of the wireless charging device was tested using a digital oscilloscope and voltage / current probes, resulting in an efficiency of 96.38% for the nanocrystalline wireless charging device used in drones, with a magnetic conductor volume of 8.220 cm³. 3 The weight is 29.125g. The wireless charging device in this embodiment has higher efficiency than Comparative Examples 1 and 2, and smaller weight and volume than Comparative Examples 1 and 2. The device basically achieves high efficiency and lightweight miniaturization.

[0060] Comparative Example 1

[0061] This comparative example demonstrates the fabrication of a low-loss nanocrystalline magnetic conductor and its wireless charging device for a drone. The specific process is as follows:

[0062] (1) The nanocrystalline alloy used in this comparative example has the following composition: Fe 74 Si 13 B8Nb2Cu1Mn2 was used to prepare an 18μm thick precursor ultrathin strip using a single-roller rapid quenching method. After crystallization, nanocrystalline ultrathin strips were obtained, which were then combined with double-sided adhesive and crushed to prepare nanocrystalline flexible sheets. Three layers of nanocrystalline flexible sheets were bonded together and coated with an ultrathin flexible PET film to form a magnetic conductor B. Four magnetic conductors B, each 44mm long and 20mm wide, were stacked to form a rectangular cuboid structure for wireless charging. Figure 5 As shown in (c).

[0063] (2) Figure 5 As shown in (c), a copper coil with a wire diameter of 2 mm is fabricated into a circular coil with an inner diameter of 32 mm and an outer diameter of 76 mm. A rectangular parallelepiped magnetic conductor is evenly distributed in a star-shaped pattern on the circular coil, forming a nanocrystalline magnetic coupling structure. The two are arranged opposite each other as the transmitter and receiver, respectively.

[0064] (3) A low-loss nanocrystalline magnetic wireless charging device for UAVs was constructed by combining the prepared transmitter and receiver, signal generator, power amplifier, transmitter compensation network, receiver compensation network, rectifier filter module, and load. The device has a power of 260W and a vertical distance of 88mm between the receiver and transmitter.

[0065] Simulation studies were conducted using simulation software, achieving a simulation efficiency of 96.05%. The magnetic coupling mechanism of the wireless charging device was tested using a digital oscilloscope and voltage / current probes. The efficiency of the nanocrystalline wireless charging device for drones was 95.79%, and the volume of the magnetic conductor was 12.503 cm³. 3 The weight is 35.345g.

[0066] The comparative wireless charging device has lower efficiency, larger weight and volume than Examples 1 and 2, and poorer overall performance.

[0067] Comparative Example 2

[0068] This comparative study demonstrates the fabrication of a low-loss nanocrystalline magnetic conductor and its wireless charging device for drones. The specific process is as follows:

[0069] (1) The nanocrystalline alloy used in this comparative example has the following composition: Fe 74 Si 13 B8Nb2Cu1Mn2 was used to prepare an 18μm thick precursor ultrathin strip using a single-roller rapid quenching method. After crystallization, nanocrystalline ultrathin strips were obtained, which were then combined with double-sided adhesive and crushed to prepare nanocrystalline flexible sheets. Subsequently, a magnetic conductor C was formed by coating both sides of the single-layer nanocrystalline flexible sheet with an ultrathin flexible PET film. Figure 3 As shown in (a), twelve magnetic conductors C, each 44 mm long and 20 mm wide, are stacked to form a rectangular cuboid structure for wireless charging. Figure 5 As shown in (d).

[0070] (2) Figure 5 As shown in (d), a copper coil with a wire diameter of 2 mm is fabricated into a circular coil with an inner diameter of 32 mm and an outer diameter of 76 mm. A rectangular parallelepiped magnetic conductor is evenly distributed in a star-shaped pattern on the circular coil, forming a nanocrystalline magnetic coupling structure. The two are arranged opposite each other as the transmitter and receiver, respectively.

[0071] (3) A low-loss nanocrystalline magnetic wireless charging device for UAVs was constructed by combining the prepared transmitter and receiver, signal generator, power amplifier, transmitter compensation network, receiver compensation network, rectifier filter module, and load. The device has a power of 280.1W and the receiver and transmitter are 88mm apart.

[0072] Simulation studies were conducted using simulation software, achieving a simulation efficiency of 95.99%. The magnetic coupling mechanism of the wireless charging device was tested using a digital oscilloscope and voltage / current probes. The efficiency of the nanocrystalline wireless charging device for drones was 95.50%, and the volume of the magnetic conductor was 30.413 cm³. 3 The weight is 60.060g.

[0073] The comparative wireless charging device has lower efficiency, larger weight and volume than Examples 1 and 2, and poorer overall performance.

[0074] Performance Analysis:

[0075] Simulation studies were conducted on Examples 1, 2, Comparative Example 1, and Comparative Example 2, and the results of efficiency, total volume of magnetic conductor, and weight are shown in Table 1.

[0076] Table 1. Wireless charging efficiency, magnet volume, and weight of Examples 1, 2, 1, and 2 (Comparative Example 1 and Comparative Example 2)

[0077]

[0078]

[0079] As shown in Table 1, Comparative Example 2 has the lowest efficiency, and also the largest weight and volume, resulting in the worst overall performance. Compared to Comparative Examples 1 and 2, the wireless charging devices of Examples 1 and 2 show improvements in efficiency, and reductions in the volume and weight of the magnetic conductor. The wireless charging simulation efficiencies of Examples 1 and 2 are both above 96.22%, while the volume of the magnetic conductor is both around 8.3 cm². 3 The weight is below 29.2g. This indicates that the wireless charging device using a 6-layer nanocrystalline magnetic conductor performs well, and the inverted trapezoidal magnetic conductor structure applied to a 6-layer magnetic conductor results in even better overall performance, achieving both high efficiency and lightweight miniaturization.

[0080] Actual performance tests were conducted on Examples 1, 2, Comparative Example 1, and Comparative Example 2. The wireless charging test distance was 85-90mm, and the power was 200-400W. The actual device efficiency, total volume of the magnetic conductor, and weight results obtained from the tests are shown in Table 2.

[0081] Table 2 shows the wireless charging efficiency, magnet volume, and weight of Examples 1, 2, Comparative Examples 1 and 2.

[0082]

[0083] As shown in Table 2, both Example 1 and Example 2 can achieve a wireless charging efficiency of over 96%, while the volume of the magnetic conductor is 8.3 cm². 3 The following designs, with a weight below 29.2g, basically meet the requirements for a high-efficiency, lightweight, and miniaturized wireless charging device for drones. Specifically, Example 1 achieves an efficiency of 96.26%, while its volume is reduced by 35.81% compared to Comparative Example 1, and by 73.61% compared to Comparative Example 2; its weight is reduced by 17.48% compared to Comparative Example 1, and by 51.44% compared to Comparative Example 2. Example 2 achieves an efficiency of 96.38%, while its volume is reduced by 34.26% compared to Comparative Example 1, and by 72.97% compared to Comparative Example 2; its weight is reduced by 17.60% compared to Comparative Example 1, and by 51.51% compared to Comparative Example 2. This demonstrates that the wireless charging device using an inverted trapezoidal structure with six layers of magnetic conductors achieves higher efficiency and a lighter, smaller size.

[0084] like Figure 1 As shown, the simulation error between the surface magnetic flux density of the coupled coil provided in the specific embodiment of the present invention and the actual test is less than 5%, which is within an acceptable error range.

[0085] like Figure 2 As shown, when the inner diameter remains constant at 32mm, the higher the number of turns of the coil, the higher the mutual inductance of the coil. When the inner diameter is 32mm and the number of turns is 20, it constitutes the coil in the specific embodiment of the present invention.

[0086] In summary, the specific embodiments of the present invention provide a low-loss nanocrystalline magnetic conductor and a wireless charging device for drones. When applied in the field of wireless charging, it has the advantages of being lightweight, compact, and highly efficient, enabling higher efficiency and smaller size of wireless charging devices, and broadening the product market and application prospects of power electronic devices.

Claims

1. A nanocrystalline magnetic conductor, characterized in that, It consists of multiple magnetic conductors A and magnetic conductors B arranged on both sides of magnetic conductors A, stacked together to form an inverted trapezoidal stacked structure; The magnetic conductor A is composed of a first nanocrystalline flexible sheet stacked structure and a protective film layer; The first nanocrystalline flexible sheet stacked structure consists of six layers of nanocrystalline flexible sheets; The protective film layer is disposed on the upper and lower surfaces of the first nanocrystalline flexible sheet stack structure; The magnetic conductor B is composed of a stacked structure of second nanocrystalline flexible sheets and a protective film layer; The second nanocrystalline flexible sheet stacked structure consists of three layers of nanocrystalline flexible sheets; The protective film layer is disposed on the upper and lower surfaces of the second nanocrystalline flexible sheet stack structure; The inverted trapezoidal stacked structure includes a wide upper part and a narrow lower part; The upper part of the magnetic conductor A has a length of 42-44 mm and a width of 20 mm. On each side of the upper part of the magnetic conductor A, there is a magnetic conductor B with a length of 2.5 mm and a width of 20 mm. The magnetic conductor A in the narrow lower part is 34-36 mm long and 20 mm wide, and magnetic conductors B with a length of 4 mm and a width of 20 mm are provided on both sides of the magnetic conductor A in the narrow lower part. The material of the first or second nanocrystalline flexible sheet includes FeCuSiBNbP, FeCuSiBNbMn, or FeCuSiBNbMo.

2. The nanocrystalline magnetic conductor according to claim 1, characterized in that, The nanocrystalline flexible sheet is obtained by combining broken nanocrystalline ultrathin strips and double-sided adhesive, and the thickness of the broken nanocrystalline ultrathin strips is 14-18 μm.

3. The nanocrystalline magnetic conductor according to claim 1, characterized in that, The protective film layer is a flexible PET film.

4. The nanocrystalline magnetic conductor according to claim 1, characterized in that, The loss of the nanocrystalline magnetic conductor described herein is less than 3.4% at 0.1 T ~ 0.25 T and 85 kHz within 20 ~ 80 °C, and the loss of the nanocrystalline magnetic conductor described herein is less than 4.1% at 0.1 ~ 0.25 T and 150 kHz within 20 ~ 80 °C.

5. A wireless charging device for unmanned aerial vehicles, characterized in that, It includes a signal generator, a power amplifier, a transmitter supplementary network, a nanocrystalline magnetic coupling structure, a receiver supplementary network, a rectifier and filter module, and a load; The nanocrystalline magnetic coupling structure includes a circular coil and a nanocrystalline magnetic conductor as described in any one of claims 1-4, wherein the nanocrystalline magnetic conductor is distributed in a cross shape on the lower and upper surfaces of the circular coil to respectively construct the transmitter and receiver. The signal generator is electrically connected to the power amplifier, the power amplifier is electrically connected to the transmitter supplementary network, and the transmitter supplementary network is electrically connected to the transmitter of the nanocrystalline magnetic coupling structure. The receiving end of the nanocrystalline magnetic coupling structure is electrically connected to the receiving end supplementary network, the receiving end supplementary network is electrically connected to the rectifier and filter module, and the rectifier and filter module is electrically connected to the load.

6. The wireless charging device for unmanned aerial vehicles according to claim 5, characterized in that, The circular coil is a hollow conductor, with an inner diameter of 32 mm and an outer diameter of 74-76 mm.

7. The wireless charging device for unmanned aerial vehicles according to claim 5, characterized in that, The power range of the wireless charging device is 200-400 W.

8. The wireless charging device for unmanned aerial vehicles according to claim 5, characterized in that, The efficiency of the wireless charging device reaches over 96%.

9. The wireless charging device for unmanned aerial vehicles according to claim 5, characterized in that, The volume of the magnetic conductors distributed in the wireless charging device is 8.3 cm². 3 The following are products weighing less than 29.2 g.

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