A wireless charging magnetic coupling device for an unmanned aerial vehicle

Abstract

The present invention relates to a magnetic coupling device for wireless charging of unmanned aerial vehicles (UAVs), comprising a transmitting unit fixed to a charging station and a receiving unit mounted on a UAV. The transmitting unit comprises a first magnetic core and a second magnetic core, both having identical L-shaped shapes and structures. A first transmitting coil is wound around the short side of the first magnetic core, and a second transmitting coil is wound around the short side of the second magnetic core. The plane in which the first magnetic core and the first transmitting coil lie is perpendicular to the plane in which the second magnetic core and the second transmitting coil lie, and the first transmitting coil and the second transmitting coil are connected in series. The receiving unit comprises a hollow receiving coil, which is mounted on the landing gear of the UAV. The present invention can concentrate the coupling magnetic field generated by the transmitting unit, achieving low leakage magnetic flux and a high coupling coefficient, thereby realizing efficient wireless charging of UAVs. The present invention enables wireless charging of multiple UAVs while avoiding limitations on the power level and size of the UAVs.

Description

Technical Field

[0001] The present invention relates to the field of wireless charging technology, and in particular to a wireless charging magnetic coupling device for unmanned aerial vehicles. Background Art

[0002] In recent years, drones have been widely used in border inspections, power inspections, forest fire prevention, and military reconnaissance. However, due to limitations in battery power density, increasing battery life requires larger and heavier batteries, which is unsuitable for drones. To extend the operating range and flight time of drones, the use of wireless charging technology to achieve highly flexible charging is a current research hotspot.

[0003] Currently, wireless charging technologies are mainly categorized into magnetic field coupling, electric field coupling, microwave, and laser types. Microwave and laser types are primarily used in the far field and are not suitable for wireless charging of drones. Electric field coupling wireless charging, due to its low coupling level and relatively low efficiency, is currently a niche application. Magnetic field coupling wireless charging technology, as a relatively common wireless charging method, has been widely researched. However, due to the unique structure of drones and their ability to carry specialized devices, the design of a magnetic coupling wireless charging system requires consideration of the receiver's compatibility with the drone's unique structure. Furthermore, electromagnetic interference from the coupling mechanism's magnetic field should be minimized, and the coupling coefficient of the coupling mechanism should be enhanced to improve wireless charging efficiency.

[0004] Currently, the most widely used magnetic coupling mechanism for wireless charging of single drones is the omnidirectional parallel coupling mechanism. Its receiving coil is mounted at the base of the two landing gear, on the anti-collision bar, or on the drone's belly. Despite its advantages of simple structure and omnidirectional energy transmission, it also suffers from inherent problems such as a high risk of magnetic flux leakage interference with the drone, a large winding area and weight of the receiving mechanism, weak coupling capability, and a significant increase in the drone's air resistance. To improve the coupling efficiency and reduce magnetic flux leakage interference for wireless charging of drones, low-magnetic flux leakage magnetic coupling mechanisms and auxiliary alignment devices have emerged. These include: a small circular receiving coil placed at the bottom of the drone's landing gear. This solution offers high magnetic flux utilization and high efficiency, but it also has a small coupling surface and limited coil diameter. Another approach is the vertical solenoid coupling mechanism, which ensures extremely low magnetic flux leakage and strong coupling capability, but requires high landing position accuracy and requires modifications to the landing gear. Finally, there is the orthogonal coupling mechanism, which is highly adaptable to drone structures, easy to install, lightweight, and has low electromagnetic interference, but its coupling capability is relatively low and requires extremely strict requirements on landing direction and position. The application of these structures in multi-UAV wireless charging systems will undoubtedly increase the complexity of the system. Summary of the Invention

[0005] The object of the present invention is to provide a magnetic coupling device for wireless charging of drones that can reduce electromagnetic interference, enhance the coupling coefficient of the magnetic coupling mechanism, and improve the wireless charging efficiency.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solutions: a magnetic coupling device for wireless charging of a drone, comprising a transmitting unit fixed on a charging station and a receiving unit installed on a drone, wherein the transmitting unit comprises a first magnetic core and a second magnetic core, both of which have the same shape and structure and are both L-shaped, a first transmitting coil is wound on the short side of the first magnetic core, and a second transmitting coil is wound on the short side of the second magnetic core, the plane where the first magnetic core and the first transmitting coil are located is perpendicular to the plane where the second magnetic core and the second transmitting coil are located, and the first transmitting coil and the second transmitting coil are connected in series; the receiving unit comprises a hollow receiving coil, which is installed on the landing gear of the drone.

[0007] The first magnetic core and the second magnetic core are made of soft ferrite.

[0008] The first transmitting coil is a multi-turn spiral structure extending from the radial inner side to the radial outer side, and the second transmitting coil is a multi-turn spiral structure converging from the radial outer side to the radial inner side. The first transmitting coil and the second transmitting coil are single-layer or multi-layer.

[0009] There are multiple transmitting units, which are closely arranged in a line to form a power supply platform.

[0010] The DC power supply is converted into a controllable rectangular wave with symmetrical positive and negative half-cycles by a high-frequency inverter circuit. The electric energy is then transferred to the first transmitting coil and the second transmitting coil by a compensation circuit. The energy is then transferred to the hollow receiving coil through a coupling relationship. The compensation circuit then compensates for the reactive power of the hollow receiving coil and inputs it into the rectifier circuit. The battery is then charged by the battery management circuit.

[0011] When the transmitting coil is aligned with the hollow receiving coil, the width of the hollow receiving coil is L, which is within the width of the transmitting coil M. The output voltage of the compensation network on the hollow receiving coil side is:

[0012]

[0013] Among them, L f is the inductance of the LCC-S compensation circuit, M ps is the mutual inductance between the transmitting coil and the hollow receiving coil, U in1 is the input voltage of the compensation network on the transmitting coil side.

[0014] When the hollow receiving coil is at the junction of two transmitting units, the width of the hollow receiving coil is L, where L has a width of L1 in one transmitting unit and a width of L2 in the other transmitting unit. L1 + L2 = L, and the output voltage is:

[0015]

[0016] Among them, M ps1 is the mutual inductance between the transmitting coil and the hollow receiving coil of the first transmitting unit, M ps2 is the mutual inductance between the transmitting coil and the hollow receiving coil of the second transmitting unit, U in1 is the input voltage of the compensation network on the transmitting coil side.

[0017] It can be seen from the above technical solution that the beneficial effects of the present invention are: First, the present invention can converge the coupling magnetic field generated by the transmitting unit to achieve the purpose of low leakage magnetic field and high coupling coefficient, thereby realizing efficient wireless charging of drones; Second, the multi-drone wireless charging system of the present invention is based on the drone wireless charging magnetic coupling mechanism to construct a power supply platform, and through technical means such as position detection, auxiliary devices, load identification, power control and load matching, it can realize wireless charging of multiple drones, and at the same time avoid being restricted by the power level and size of the drones. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of a transmitting unit in the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of a hollow receiving coil and a UAV landing gear in the present invention;

[0020] Figure 3 yes Figure 1 Schematic diagram of the distribution of magnetic lines of force and the position of the receiving coil;

[0021] Figure 4 This is a schematic diagram of the drone when it is charging;

[0022] Figure 5 It is a schematic diagram of the circuit principle of a transmitting unit and a receiving unit of the present invention;

[0023] Figure 6 It is a schematic diagram of a power supply platform composed of multiple transmitting units in the present invention;

[0024] Figure 7 It is a schematic diagram of multiple hollow receiving coils on a power supply platform in the present invention;

[0025] Figure 8 It is a schematic diagram of the hollow receiving coil in the present invention being located in the same transmitting unit;

[0026] Figure 9 This is a schematic diagram of the hollow receiving coil of the present invention at the junction of two transmitting units;

[0027] Figure 10 It is a schematic diagram of the circuit principle of the power supply platform in the present invention. DETAILED DESCRIPTION

[0028] like Figure 1 、 2 As shown, a magnetic coupling device for wireless charging of a drone includes a transmitting unit fixed to a charging station and a receiving unit installed on the drone. The transmitting unit includes a first magnetic core 1 and a second magnetic core 2. The two have the same shape and structure and are both L-shaped. A first transmitting coil 3 is wound around the short side of the first magnetic core 1, and a second transmitting coil 4 is wound around the short side of the second magnetic core 2. The plane where the first magnetic core 1 and the first transmitting coil 3 are located is perpendicular to the plane where the second magnetic core 2 and the second transmitting coil 4 are located. The first transmitting coil 3 and the second transmitting coil 4 are connected in series. When current is passed through, a bipolar transmitting magnetic field with a 90° difference is generated, as shown in FIG. Figure 3 As shown; the receiving unit includes a hollow receiving coil 5, and the hollow receiving coil 5 is mounted on the UAV landing gear 6.

[0029] The first and second magnetic cores 1 and 2 are made of soft ferrite. The first transmitting coil 3 is a multi-turn helical structure extending radially inward to radially outward, while the second transmitting coil 4 is a multi-turn helical structure converging radially inward from radially outward. The first and second transmitting coils 3 and 4 can be single-layer or multi-layer. The magnetic flux generated by the transmitting coils forms a loop through the first and second magnetic cores 1 and 2, resulting in minimal magnetic flux leakage.

[0030] The hollow receiving coil 5 is placed in the bipolar transmitting magnetic field generated by the transmitting unit to achieve energy collection, such as Figure 4 As shown in the figure, since the transmitting magnetic field has the effect of converging the magnetic field, the magnetic flux can more easily pass through the hollow receiving coil cross section, achieving the effect of low leakage magnetic flux and high coupling.

[0031] The circuit principle of the wireless power supply system with a transmitting unit and a receiving unit is as follows Figure 5 As shown, the DC power supply is converted into a controllable rectangular wave with symmetrical positive and negative half-cycles by a high-frequency inverter circuit. The electric energy is then transferred to the first transmitting coil 3 and the second transmitting coil 4 by a compensation circuit. The energy is then transferred to the hollow receiving coil 5 through a coupling relationship. The compensation circuit then compensates for the reactive power of the hollow receiving coil 5 and inputs the power into the rectifier circuit. The battery is then charged by the battery management circuit. The number of the transmitting units is multiple, and the multiple transmitting units are closely arranged in a line to form a power supply platform 8. Figure 6 shown.

[0032] like Figure 6 The positional relationship between the power supply platform 8 and the multiple hollow receiving coils 5 of the multi-UAV wireless charging system is shown in FIG. Figure 7 As shown; the circuit principle of the multi-UAV wireless charging system, refer to Figure 10 Each transmitting unit has an independent inverter circuit and compensation circuit, and its principle is the same as Figure 5 Each drone has a hollow receiving coil 5, a rectifier circuit, a battery management circuit and a battery. When the hollow receiving coil 5 is placed on the transmitting platform, the corresponding one or several transmitting units start working to wirelessly charge the drone battery.

[0033] When the drone lands on the charging platform, a simple auxiliary device is used to push the drone into the magnetic circuit of the power supply platform 8. The power supply unit of the power supply platform 8 detects whether there is a load, thereby turning on the relevant transmitting unit to generate a transmitting magnetic field.

[0034] To ensure that the excitation current is constant and unaffected by coupling coefficient and load changes, the primary side adopts an LCC compensation structure. To avoid adding extra volume and weight to the drone, the secondary side adopts a simple S compensation structure. In addition, the voltage-type inverter structure is adopted. The LCC-S has a constant voltage output characteristic, and the output voltage is not affected by load changes. The drone battery can be charged through simple control.

[0035] like Figure 8 As shown, when the transmitting coil is aligned with the hollow receiving coil 5, the width L of the hollow receiving coil 5 is within the width M of the transmitting coil, and the output voltage of the compensation network on the hollow receiving coil 5 side is:

[0036]

[0037] Among them, L f is the inductance of the LCC-S compensation circuit, M ps is the mutual inductance between the transmitting coil and the hollow receiving coil 5, U in1 is the input voltage of the compensation network on the transmitting coil side.

[0038] like Figure 9 As shown, when the hollow receiving coil 5 is at the junction of two transmitting units, the width of the hollow receiving coil 5 is L, where L has a width of L1 in one transmitting unit and a width of L2 in the other transmitting unit, L1+L2=L, and the output voltage is:

[0039]

[0040] Among them, M ps1 is the mutual inductance between the transmitting coil of the first transmitting unit and the hollow receiving coil 5, M ps2is the mutual inductance between the transmitting coil of the second transmitting unit and the hollow receiving coil 5, U in1 is the input voltage of the compensation network on the transmitting coil side.

[0041] In summary, the present invention can converge the coupling magnetic field generated by the transmitting unit to achieve the purpose of low leakage magnetic field and high coupling coefficient, thereby realizing efficient wireless charging of drones; the multi-drone wireless charging system of the present invention is based on the drone wireless charging magnetic coupling mechanism, constructs a power supply platform 8, and realizes wireless charging of multiple drones through technical means such as position detection, auxiliary devices, load identification, power control and load matching, while avoiding the limitations of drone power level and size.

Claims

1. A magnetic coupling device for wireless charging of drones, characterized by: The invention comprises a transmitting unit fixed on a charging station and a receiving unit installed on a drone, wherein the transmitting unit comprises a first magnetic core (1) and a second magnetic core (2), both of which have the same shape and structure and are both L-shaped, a first transmitting coil (3) is wound on the short side of the first magnetic core (1), and a second transmitting coil (4) is wound on the short side of the second magnetic core (2), the plane where the first magnetic core (1) and the first transmitting coil (3) are located is perpendicular to the plane where the second magnetic core (2) and the second transmitting coil (4) are located, and the first transmitting coil (3) and the second transmitting coil (4) are connected in series; the receiving unit comprises a hollow receiving coil (5), and the hollow receiving coil (5) is installed on the landing gear (6) of the drone; The first magnetic core (1) and the second magnetic core (2) are made of soft ferrite; The first transmitting coil (3) is a multi-turn helical structure extending from the radial inner side to the radial outer side, and the second transmitting coil (4) is a multi-turn helical structure converging from the radial outer side to the radial inner side. The first transmitting coil (3) and the second transmitting coil (4) are single-layer or multi-layer; There are multiple transmitting units, and the multiple transmitting units are closely arranged in a line to form a power supply platform (8); The DC power supply is converted into a controllable rectangular wave with positive and negative half-cycle symmetry by a high-frequency inverter circuit, and the electric energy is transmitted to the first transmitting coil (3) and the second transmitting coil (4) by a compensation circuit, and the energy is transmitted to the hollow receiving coil (5) through a coupling relationship. The reactive power of the hollow receiving coil (5) is then compensated by the compensation circuit and input into the rectifier circuit, and the battery is charged by the battery management circuit. To ensure constant excitation current and unaffected by coupling coefficient and load changes, the primary side adopts an LCC compensation structure. To avoid adding extra volume and weight to the drone, the secondary side adopts a simple S-compensation structure. When the transmitting coil is aligned with the hollow receiving coil (5), the width L of the hollow receiving coil (5) is within the width M of the transmitting coil, and the output voltage of the compensation network on the hollow receiving coil side is: （1） in, is the inductance value of the LCC-S compensation circuit, is the mutual inductance between the transmitting coil and the air-core receiving coil, is the input voltage of the compensation network on the transmitting coil side; When the hollow receiving coil (5) is at the junction of two transmitting units, the width of the hollow receiving coil (5) is L, where L has a width of L1 in one transmitting unit and a width of L2 in the other transmitting unit, L1+L2=L, and the output voltage is: （2） in, is the mutual inductance between the transmitting coil and the hollow receiving coil of the first transmitting unit, is the mutual inductance between the transmitting coil and the hollow receiving coil of the second transmitting unit, is the input voltage of the compensation network on the transmitting coil side.

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