An arch-shaped electric field coupling mechanism and a UAV wireless charging system based on a double-sided LC compensation network

Abstract

The application relates to the technical field of unmanned aerial vehicle wireless charging, and discloses an arch-shaped electric field coupling mechanism and an unmanned aerial vehicle wireless charging system based on a double-sided LC compensation network. A transmitting end is arranged on a charging platform, and a receiving end is arranged on the inner side of a foot stand or the inner side of a bottom structure of a machine body. The two adopt relatively arranged arch-shaped electrode plate structures, and the inner contour size of the receiving end is greater than the outer contour size of the transmitting end, so that the guiding cooperation is formed when landing, and the anti-deviation capability in the X-axis direction and the Y-axis direction is improved. The system adopts a double-sided LC compensation network, works at a constant-current output point, and realizes input zero-phase-angle operation, so that the wireless energy transmission efficiency and operation stability are improved.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, specifically to an arch-shaped electric field coupling mechanism and a wireless charging system for unmanned aerial vehicles based on a bilateral LC compensation network. Background Technology

[0002] With the widespread application of drones in fields such as inspection, surveying, security, logistics, agricultural plant protection, and emergency rescue, their insufficient endurance has become a significant factor limiting continuous operation capabilities and automation levels. Existing contact charging methods typically require manual plugging and unplugging or high-precision mechanical docking, resulting in low automation levels and making it difficult to meet the application requirements of drones for autonomous landing and autonomous recharging.

[0003] Existing electric field-coupled wireless charging structures mostly adopt planar, ring, or other conventional fixed structures. These structures have poor adaptability to the spatial shape of the drone's fuselage and landing gear, making installation and integration difficult, and requiring high precision in landing position and attitude. When the drone experiences lateral or rotational deviation during landing, it can easily lead to a reduction in coupling area and a decrease in coupling capability, thereby affecting wireless power transmission efficiency and system stability.

[0004] Furthermore, if the compensation network design is unreasonable, the system may suffer from problems such as insufficient resonance matching capability, large reactive power, significant input phase shift, and insufficient output stability. Therefore, it is necessary to propose a wireless charging system that can be adapted to the inner structure of the drone landing gear, has guiding and correction capabilities, and can work with a bilateral LC compensation network to achieve constant current output and zero input phase angle operation. Summary of the Invention

[0005] The purpose of this invention is to provide an arch-shaped electric field coupling mechanism and a wireless charging system for unmanned aerial vehicles based on a bilateral LC compensation network, so as to solve the problems of poor adaptability of coupling structure, insufficient anti-offset capability, and insufficient wireless power transmission efficiency and operational stability in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An arched electric field coupling mechanism includes a transmitter and a receiver. The transmitter is mounted on a wireless charging platform, and the receiver is mounted inside the landing gear or the bottom structure of a drone. The transmitter includes a first transmitting arched electrode plate and a second transmitting arched electrode plate, and the receiver includes a first receiving arched electrode plate and a second receiving arched electrode plate. The first transmitting arched electrode plate and the first receiving arched electrode plate are arranged opposite to each other, and the second transmitting arched electrode plate and the second receiving arched electrode plate are arranged opposite to each other to form an electric field coupling channel between the opposite electrodes. The inner contour dimension of the receiver is larger than the outer contour dimension of the corresponding transmitter, so that the receiver can form a guiding fit along the outer contour of the transmitter when the drone lands, and achieve adaptive installation.

[0008] Preferably, both the transmitter and receiver adopt an arched curved surface structure, with the receiver conforming to the inner contour of the UAV landing gear to improve structural integration.

[0009] Preferably, the arched curved surface structure has guiding and correction capabilities. When the UAV has a positional deviation in the X-axis direction, Y-axis direction, or rotation direction around the vertical axis, the receiver can self-correct relative to the transmitter under the action of gravity and the guiding effect of the curved surface, thereby improving the system's anti-offset capability in the X-axis direction and rotation angle direction, and maintaining good anti-offset performance in the Y-axis direction.

[0010] Preferably, the transmitting end is composed of an insulating substrate and a first conductive layer disposed on its surface, and the receiving end is composed of a lightweight insulating substrate and a second conductive layer disposed on its surface, with an insulating isolation layer provided on the outer surface of the first conductive layer and the second conductive layer.

[0011] Preferably, both the first conductive layer and the second conductive layer can be made of copper foil or aluminum foil, and the insulating layer can be made of PVC, polyimide or other insulating materials.

[0012] This invention also provides a wireless charging system for unmanned aerial vehicles based on a bilateral LC compensation network, including a transmitting circuit, a receiving circuit, and the aforementioned arch-shaped electric field coupling mechanism; the transmitting circuit includes a DC power supply, an inverter, a transmitting-side compensation inductor, a transmitting-side compensation capacitor, and a transmitting electrode; the receiving circuit includes a receiving electrode, a receiving-side compensation inductor, a receiving-side compensation capacitor, a rectifier, and a load; under the action of the high-frequency AC power output by the inverter, an alternating electric field is formed between the relatively arranged transmitting and receiving electrodes, and under the action of the bilateral LC compensation network, electrical energy is transferred to the load through displacement current.

[0013] Preferably, the bilateral LC compensation network is designed to operate at a constant current output operating point while simultaneously satisfying the zero phase angle condition of the input, so as to reduce the reactive power of the system and improve the resonance matching capability and transmission stability.

[0014] Compared with the prior art, the advantages of this invention are as follows:

[0015] I. The arch-shaped coupling mechanism proposed in this invention can be well fitted and installed on the inside of the UAV landing gear or the bottom structure of the fuselage, significantly improving the adaptability of the coupling structure to the shape of the UAV and solving the problem of difficult installation and integration of existing wireless coupling structures.

[0016] Second, the arch-shaped coupling mechanism has a certain guiding and correction capability. When there is a deviation in the landing of the UAV, it can achieve self-correction through the guiding effect of the curved surface and the structural matching relationship, thereby significantly improving the system's anti-deviation capability in the X-axis direction and maintaining good anti-deviation performance in the Y-axis direction.

[0017] Third, this invention adopts a bilateral LC compensation network, the system is designed to operate at a constant current output point, and can achieve zero phase angle operation, thereby effectively reducing reactive power, improving resonance matching capability, wireless power transmission efficiency and system operation stability.

[0018] Fourth, by coordinating the design of the arch-shaped coupling mechanism with the bilateral LC compensation network, the system can still maintain relatively stable output characteristics under certain offset conditions of the UAV, which has good engineering application value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the receiver and transmitter structures installed inside the drone tripod of the present invention.

[0020] Figure 2 This is a schematic diagram of the transmitter and receiver of the present invention.

[0021] Figure 3 This is a block diagram illustrating the principle of the wireless charging system based on a bilateral LC compensation network according to the present invention.

[0022] Figure 4 This is a schematic diagram of the coupling capacitance change under the X-axis offset condition of the present invention.

[0023] Figure 5 This is a schematic diagram of the coupling capacitance change under Y-axis offset conditions according to the present invention.

[0024] Figure 6 This is a diagram showing the electric field intensity distribution of the arch-shaped coupling mechanism of the present invention.

[0025] Figure 7 This is a diagram showing the electric field vector distribution of the arch-shaped coupling mechanism of the present invention.

[0026] Figure 8 This is a flowchart of the system parameter design for this invention.

[0027] Figure 9 This is a simulation circuit model diagram of the system of the present invention.

[0028] Figure 10 This is a ZPA simulation waveform diagram of the system of this invention.

[0029] Figure 11 These are simulation waveforms of the current, power, and efficiency of the system of this invention. Detailed Implementation

[0030] The present invention will be further illustrated by specific embodiments below, but the scope of protection of the present invention is not limited to the following embodiments.

[0031] Example 1: An arched electric field coupling mechanism includes a transmitter and a receiver. The transmitter is fixed to a wireless charging platform, and the receiver is fixed to the bottom of a drone's fuselage or the inside of its landing gear. The transmitter includes a first transmitting arched electrode plate and a second transmitting arched electrode plate, and the receiver includes a first receiving arched electrode plate and a second receiving arched electrode plate. The area of ​​the corresponding electrode plate on the receiver is slightly larger than that on the transmitter, and the inner contour dimension of the receiver is larger than the outer contour dimension of the transmitter, so as to form a covering or interlocking relationship when the drone lands.

[0032] Preferably, the first and second receiving arched plates have an arch height of 198 mm, an arch width of 200 mm, and a length of 260 mm; the first and second transmitting arched plates have an arch height of 188 mm, an arch width of 200 mm, and a length of 240 mm; and the mating gap between the transmitting end and the receiving end is 10 mm.

[0033] Preferably, the conductive layer material of both the transmitter and receiver is copper foil with a thickness of 0.5 mm; the insulating layer material is PVC with a thickness of 0.1 mm.

[0034] When there is a lateral deviation during the landing of the UAV, the receiver can slide relative to the arched guide surface of the transmitter and gradually move towards the coupling center under the action of gravity, thereby reducing the lateral deviation and improving the coupling stability.

[0035] Example 2: A wireless charging system for unmanned aerial vehicles (UAVs) based on a bilateral LC compensation network, comprising a transmitting circuit, a receiving circuit, and the aforementioned arch-shaped electric field coupling mechanism. The transmitting circuit includes a DC power supply Uin, a full-bridge inverter, a transmitting-side compensation inductor L1, a transmitting-side compensation capacitor Cex1, a first transmitting plate P1, and a second transmitting plate P2; the receiving circuit includes a first receiving plate P3, a second receiving plate P4, a receiving-side compensation capacitor Cex2, a receiving-side compensation inductor L2, a full-bridge rectifier, and an equivalent load RL.

[0036] In this system, the first transmitting plate P1 and the first receiving plate P3 are equivalent to the first coupling capacitor CE1, and the second transmitting plate P2 and the second receiving plate P4 are equivalent to the second coupling capacitor CE2. These two plates, connected in series, are equivalent to the total coupling capacitor CM. After the inverter converts the DC power supply to high-frequency AC power, the transmitting-side LC compensation branch, the total coupling capacitor CM, and the receiving-side LC compensation branch together form a bilateral compensation resonant network, enabling the system to operate in a resonant state at the target operating frequency.

[0037] Example 3: A system parameter design method. First, the rated charging power, load impedance RL, DC input voltage Uin, and target operating frequency f of the target UAV are determined. Second, the external dimensions of the arch-shaped coupling mechanism are determined based on the dimensions of the UAV's fuselage bottom or landing gear, installation space, and structural symmetry requirements. Third, a three-dimensional finite element model is established based on the geometric dimensions of the coupling mechanism, and the six coupling capacitors are obtained through ANSYS Maxwell electrostatic field simulation, thereby obtaining the total coupling capacitance CM. Finally, based on the total coupling capacitance CM, the target operating frequency f, and the load requirements, the transmitting-side compensation inductor L1, the transmitting-side compensation capacitor Cex1, the receiving-side compensation inductor L2, and the receiving-side compensation capacitor Cex2 are calculated, and the output power, efficiency, and current are verified through Simulink system simulation to confirm whether they meet the design requirements.

[0038] Preferably, the electric field simulation software is ANSYS Maxwell, the circuit simulation software is MATLAB / Simulink, the air domain size is 360mm×300mm×297.6mm, the outer boundary condition is a zero potential boundary, and the mesh accuracy is an adaptive refinement method.

[0039] To enable the bilateral LC compensation network to achieve constant current output and zero-phase-angle input operation while meeting the system output requirements, this invention further proposes a parameter design method that matches the arch-shaped coupling mechanism.

[0040] The parameter design method of the system of this invention is as follows: First, the six basic capacitance parameters C13, C24, C14, C23, C12 and C34 of the coupling mechanism are measured or simulated, and then the equivalent primary capacitance CP, equivalent secondary capacitance CS and total coupling mutual capacitance CM are calculated:

[0041] (1)

[0042] Furthermore, the primary-side total compensation capacitor C1 and the secondary-side total compensation capacitor C2 are defined as follows:

[0043] (2)

[0044] Under constant current output and zero phase angle input conditions, the bilateral LC compensation network satisfies:

[0045] (3)

[0046] The coupling coefficient k is obtained from the target output current, input DC voltage, duty cycle, and operating frequency using the following formula:

[0047] (4)

[0048] After determining k, C1 and C2 can be obtained using the following formula.

[0049] (5)

[0050] L1 and L2 can be obtained using formulas (3) and (5).

[0051] (6)

[0052] After completing the initial parameter calculations, the system input phase, output current, and device voltage stress are verified using a circuit simulation model or a field-circuit co-simulation model. Based on the verification results, the compensation parameters are corrected to obtain the final bilateral LC compensation parameters. If necessary, the secondary compensation inductor L2 can be slightly adjusted to make the input impedance slightly inductive, which facilitates soft switching of the switching devices.

[0053] Example 4: To verify the feasibility of the arch-shaped coupling mechanism and bilateral LC compensation network proposed in this invention, a three-dimensional electric field simulation model of the transmitter and receiver was established, and a system circuit simulation model was established to analyze its electric field intensity distribution, electric field vector distribution, system resonance state, and output characteristics under different offset conditions.

[0054] Simulation results show that the electric field strength near the coupled plates is high and gradually weakens with increasing distance from the plates, indicating that the electric field energy is mainly concentrated in the region near the opposite plates. The electric field vector is mainly distributed between the opposite plates, indicating that the arch-shaped structure can form a relatively concentrated coupling channel. Under the action of the bilateral LC compensation network, the system can achieve good resonance matching at the target operating frequency, and the receiver output meets the load requirements. Under the conditions of X-axis offset, Y-axis offset, and rotation angle offset, due to the guiding correction capability of the arch-shaped coupling mechanism, the opposite plates can still maintain a good overlap relationship, and the system output performance decreases only slightly.

[0055] Preferably, the DC input voltage Uin is 20V, the target operating frequency f is 300kHz, the load impedance RL is 20Ω, the target output power Pout is 80W, and the target output current Io is 2A; the transmitting-side compensation inductor L1 is 207.7uH, the transmitting-side compensation capacitor Cex1 is 1.33nF; the receiving-side compensation inductor L2 is 207.7uH, and the receiving-side compensation capacitor Cex2 is 1.33nF.

[0056] Preferably, the input voltage is 20V, the load is 20Ω, the output current is 2A, the output power is 80W, and the system efficiency is 85.62%.

Claims

1. An arch-shaped electric field coupling mechanism, characterized in that: The device includes a transmitter and a receiver. The transmitter is mounted on a wireless charging platform, and the receiver is mounted inside the drone's landing gear or the bottom structure of the drone's fuselage. The transmitter includes a first transmitting arched electrode plate and a second transmitting arched electrode plate, and the receiver includes a first receiving arched electrode plate and a second receiving arched electrode plate. The first transmitting arched electrode plate and the first receiving arched electrode plate are positioned opposite each other, and the second transmitting arched electrode plate and the second receiving arched electrode plate are positioned opposite each other to form an electric field coupling channel between the opposing electrodes. The inner contour dimension of the receiver is larger than the outer contour dimension of the corresponding transmitter, so that the receiver can form a guiding fit along the outer contour of the transmitter when the drone lands.

2. The arch-shaped electric field coupling mechanism according to claim 1, characterized in that: Both the transmitter and receiver adopt an arched curved surface structure, and the receiver is set to fit the inner contour of the drone's footrest.

3. The arch-shaped electric field coupling mechanism according to claim 1, characterized in that: The arched curved surface structure has guiding and correction capabilities. When the UAV has a positional deviation in the X-axis direction, Y-axis direction, or rotation angle direction, the receiver can self-correct relative to the transmitter under the action of gravity and the guiding effect of the curved surface.

4. The arch-shaped electric field coupling mechanism according to claim 1, characterized in that: The transmitting end is composed of an insulating substrate and a first conductive layer disposed on its surface, and the receiving end is composed of a lightweight insulating substrate and a second conductive layer disposed on its surface. An insulating isolation layer is provided on the outer surface of the first conductive layer and the second conductive layer.

5. The arch-shaped electric field coupling mechanism according to claim 4, characterized in that: Both the first conductive layer and the second conductive layer are made of copper foil or aluminum foil, and the insulating layer is made of PVC, polyimide or other insulating materials.

6. A wireless charging system for unmanned aerial vehicles based on a bilateral LC compensation network, characterized in that: The device includes a transmitting circuit, a receiving circuit, and an arch-shaped electric field coupling mechanism as described in any one of claims 1 to 5. The transmitting circuit includes a DC power supply, an inverter, a transmitting-side compensation inductor, a transmitting-side compensation capacitor, a first energy transmitting plate, and a second energy transmitting plate. The receiving circuit includes a first energy receiving plate, a second energy receiving plate, a receiving-side compensation inductor, a receiving-side compensation capacitor, a rectifier, and a load. The first energy transmitting plate and the first energy receiving plate are arranged opposite each other to form a first coupling capacitor, and the second energy transmitting plate and the second energy receiving plate are arranged opposite each other to form a second coupling capacitor. Under the action of the high-frequency AC power output by the inverter, an alternating electric field is formed between the opposite plates, and under the action of the bilateral LC compensation network, electrical energy is transmitted to the load through displacement current.

7. A wireless charging system for unmanned aerial vehicles based on a bilateral LC compensation network according to claim 6, characterized in that: The bilateral LC compensation network is designed to operate at a constant current output operating point while simultaneously satisfying the input zero phase angle condition.

8. A wireless charging system for unmanned aerial vehicles based on a bilateral LC compensation network according to claim 6, characterized in that: The first coupling capacitor is Ce1, the second coupling capacitor is Ce2, and the total coupling capacitor is CM.

9. A wireless charging system for unmanned aerial vehicles based on a bilateral LC compensation network according to claim 6, characterized in that: The inverter is a full-bridge inverter or a half-bridge inverter, and the rectifier is a full-bridge rectifier or a synchronous rectifier.

10. A wireless charging system for unmanned aerial vehicles based on a bilateral LC compensation network according to claim 6, characterized in that: The receiving-side compensation inductor and receiving-side compensation capacitor are located in the mounting area inside the UAV fuselage, inside the landing gear cavity, or near the receiving electrode plate.

11. A wireless charging platform for unmanned aerial vehicles, characterized in that: It includes the transmitting circuit and transmitting end, and the receiving circuit and receiving end in the wireless charging system according to any one of claims 6 to 10.

Images