An unmanned aerial vehicle wireless charging system based on a lightweight anti-bias wireless power coupling mechanism based on electric field coupling and a control method thereof

Abstract

The application discloses a kind of unmanned aerial vehicle wireless charging systems of lightweight anti-deviation wireless power transmission coupling mechanism based on electric field coupling and control method thereof, the system includes lightweight anti-deviation wireless power transmission coupling mechanism, platform side circuit and airborne side circuit;The lightweight anti-deviation wireless power transmission coupling mechanism includes large size platform end and small size airborne end;The platform side circuit includes sequentially connected DC power supply, full-bridge inverter, power regulation and voltage conversion topology unit, and the airborne side circuit includes sequentially connected full-bridge rectifier and unmanned aerial vehicle battery load.The coupling mechanism of the application is simple to make, low in cost, airborne side light in weight, can greatly improve the utilization rate of metal plate coupling, has 360 ° angle anti-deviation and strong lateral anti-deviation ability, and simultaneously within the designable unmanned aerial vehicle landing position deviation range, the system of the application can meet the efficient and stable wireless power supply demand of unmanned aerial vehicle battery load.

Description

Technical Field

[0001] This invention relates to the field of wireless charging technology for unmanned aerial vehicles (UAVs), specifically to a lightweight anti-biased wireless power transmission coupling mechanism for UAVs based on electric field coupling and its control method. Background Technology

[0002] In recent years, my country's civilian drone market has grown rapidly, with drones being widely used in various fields such as traffic monitoring, film and television photography, fire rescue, agricultural plant protection, environmental surveying, infrastructure inspection, and power line inspection. However, the main challenge currently facing drone applications is the limitation of battery capacity, which restricts flight time and operating range. The current charging method for drones is mainly manual plugging and unplugging, which has a low degree of automation, cannot achieve the goal of unattended and automated operation, and poses safety hazards such as aging cables and electrical leakage. The emergence of wireless charging technology provides drones with a new power supply method.

[0003] Currently, wireless charging is mainly achieved through magnetic field coupling and electric field coupling. Magnetic field coupling wireless charging technology suffers from problems such as heavy coupling mechanism, high cost, poor structural adaptability, and significant electromagnetic interference, creating inherent bottlenecks in its application in the field of drone wireless charging. Electric field coupling wireless charging technology has the following advantages: 1) The metal plates of the electric field coupling mechanism are lightweight, low-cost, easy to manufacture, and highly flexible; 2) During system operation, most of the electric field is confined between the two metal plates, resulting in a small leakage electric field and minimal electromagnetic interference to the surrounding environment; 3) When the system operates in an environment with surrounding metal conductors, eddy current losses are not generated in the metal conductors.

[0004] Applying electric field coupling wireless charging technology to drone wireless charging presents the following challenges: 1) The coupling mechanism must be lightweight, compact, easy to install, have high metal plate coupling utilization, and not affect the normal operation of the drone's fuselage equipment; 2) The coupling mechanism must have certain angular and lateral offset resistance capabilities; 3) The drone wireless charging system must have constant voltage output characteristics and controllable output voltage, enabling efficient and stable power transmission to the drone's battery load and maximizing the lightweighting of the airborne side. Summary of the Invention

[0005] To address the challenges of lightweighting the airborne components of drones and constant-voltage charging of drone batteries, this invention provides a lightweight, anti-biased wireless power transmission coupling mechanism for drones based on electric field coupling. This coupling mechanism offers advantages such as lightweight design, ease of manufacture, low cost, strong structural compatibility, high utilization rate of metal plate coupling, 360° anti-offset capability, and strong lateral anti-offset capability, without affecting the carrying of other functional devices on the drone's fuselage. The drone wireless charging system features constant-voltage output characteristics, fewer drone-side components, and controllable output voltage.

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

[0007] A lightweight anti-bias wireless power transmission coupling mechanism for unmanned aerial vehicles (UAVs) based on electric field coupling includes a lightweight anti-bias wireless power transmission coupling mechanism, a platform-side circuit, and an airborne-side circuit. The lightweight anti-bias wireless power transmission coupling mechanism includes a large platform end composed of an inner circular aluminum plate, an outer circular aluminum plate, and a first circular insulating plate, and a small airborne end composed of a uniformly drilled inner circular aluminum foil, a uniformly drilled outer circular aluminum foil, and a second circular insulating plate.

[0008] The inner disc aluminum plate and the outer ring aluminum plate cover the upper surface of the first disc-shaped insulating plate, and the uniformly drilled inner disc aluminum foil and the uniformly drilled outer ring aluminum foil cover the lower surface of the second disc-shaped insulating plate.

[0009] The platform-side circuit includes a DC power supply, a full-bridge inverter, and a power regulation and voltage conversion topology unit connected in sequence; the airborne-side circuit includes a full-bridge rectifier and a UAV battery load connected in sequence.

[0010] The power regulation and voltage conversion topology unit includes inductor L1, inductor L2, capacitor C1, and capacitor C2;

[0011] The inductor L1 and the capacitor C2 are sequentially connected between the first connection terminal of the full-bridge inverter and the inner circular aluminum plate. The capacitor C1 is connected between the common connection terminal of the inductor L1 and the capacitor C2 and the outer circular aluminum plate. The inductor L2 is connected between the common connection terminal of the capacitor C2 and the inner circular aluminum plate and the outer circular aluminum plate. The second connection terminal of the full-bridge inverter is connected to the outer circular aluminum plate.

[0012] The uniformly drilled inner disc aluminum foil and the uniformly drilled outer ring aluminum foil are respectively connected to the first connection end and the second connection end of the full-bridge rectifier.

[0013] Furthermore, the platform end is installed on the ground or on a UAV take-off and landing platform, and the airborne end is installed between the two crossbars at the bottom of the UAV landing gear.

[0014] Furthermore, a thin insulating layer is provided on the outer surfaces of the inner disc aluminum plate, the outer ring aluminum plate, the uniformly drilled inner disc aluminum foil, and the uniformly drilled outer ring aluminum foil.

[0015] Furthermore, the radius of the inner disc aluminum plate is 10-30 mm larger than the radius of the uniformly drilled inner disc aluminum foil.

[0016] Furthermore, the inner radius of the outer ring aluminum plate is 10-30 mm smaller than the inner radius of the uniformly drilled outer ring aluminum foil.

[0017] Furthermore, the outer ring radius of the outer ring aluminum plate is 10-30 mm larger than the outer ring radius of the uniformly drilled outer ring aluminum foil.

[0018] Furthermore, the second disc-shaped insulating plate is made of a thin insulating material.

[0019] Furthermore, the inner circular aluminum plate and the uniformly drilled inner circular aluminum foil are coupled to form a coupling capacitor C. p1 The outer circular aluminum plate and the uniformly drilled outer circular aluminum foil are coupled to form a coupling capacitor C. p2 The equivalent coupling capacitance of the coupling mechanism can be calculated as C. p =C p1 C p2 / (C p1 +C p2 When the system is working, a coupled electric field is established between the inner circular aluminum plate, the uniformly drilled inner circular aluminum foil, the outer circular aluminum plate, and the uniformly drilled outer circular aluminum foil, and wireless power transmission to the UAV battery load is completed under the action of the coupled electric field.

[0020] Furthermore, the value of capacitor C2 is the equivalent coupling capacitance C of the coupling mechanism. p k times, where k>1.

[0021] This invention also provides a control method for a UAV wireless charging system based on a lightweight anti-polarization wireless power transmission coupling mechanism using electric field coupling, comprising the following steps:

[0022] S1: Simplified analysis using the fundamental frequency approximation method, inverter output voltage for:

[0023]

[0024] Among them, E DC ω is the system's DC input voltage, and ω is the system's operating angular frequency;

[0025] S2: Equivalent impedance R before rectification on the airborne side of the system eq for:

[0026]

[0027] S3: Z-axis of the equivalent circuit of a drone wireless charging system in1 The network is equivalent to an inductor L m With a resistor R m By using a series network, the system circuit can be equivalent to a T-LCL network. Neglecting the losses of reactive components in the circuit, the circuit Z of the drone wireless charging system can be calculated using circuit principles. in1 The input impedance of the network is:

[0028] Z in1 =R m +jωL m (1)

[0029] in,

[0030] In the formula, ω is the system's operating angular frequency;

[0031] S4: Write the KVL equations for the equivalent T-LCL network:

[0032]

[0033] S5: When the resonance relationship is satisfied At that time, the current gain G1 and input impedance Z1 of the T-LCL network are:

[0034]

[0035] As can be seen from equation (4), under constant voltage input conditions, the system output current is Only with input voltage The capacitor C1 is related to the resonant angular frequency ω and is independent of the load size. This T-LCL network has constant voltage input and constant current output characteristics, and the system input impedance is purely resistive. The system has a high power factor and can ensure efficient and stable power transmission.

[0036] S6: At this point, the Z-axis of the equivalent circuit of the drone's wireless charging system... in1 The network is equivalent to a T-CLC network with a constant current source input;

[0037] Write the KVL equations for a T-CLC network with constant current source input:

[0038]

[0039] S7: When the resonance relationship is satisfied At that time, the voltage gain G2 of the T-CLC network is:

[0040]

[0041] S8: The output voltage gain G3 of the drone wireless charging system can be calculated from equations (4) and (6):

[0042]

[0043] As can be seen from equation (7), the output voltage of the drone wireless charging system is... Only with input voltage Capacitor C1 and the equivalent coupling capacitance C of the coupling mechanism p Regarding the coupling mechanism, when the airborne end experiences a 360° angular shift and a lateral shift within the range of 10–30 mm, the airborne end can still remain entirely within the effective coupling area, and the equivalent coupling capacitance C... p With almost no change, the system can achieve efficient and stable power transfer to the drone's battery load by adjusting capacitor C1 and the equivalent coupling capacitor C of the coupling mechanism. p The proportional relationship can achieve the target of controlling the output voltage of the control system.

[0044] Compared with the prior art, the present invention has the following technical advantages:

[0045] 1. Compared with other planar electric field coupling mechanisms, the airborne end of the coupling mechanism of this invention uses aluminum foil and uniform drilling to make full use of the edge effect of the charge distribution of the metal plates, which greatly improves the coupling utilization rate of the metal plates and realizes the lightweighting of the airborne end of the coupling mechanism. In addition, the metal plates of the platform end and the airborne end are circular and their sizes are "large to small", which can ensure that the UAV can undergo 360° angular displacement and a certain range of lateral displacement when landing for wireless charging, and has better anti-displacement performance.

[0046] 2. Compared with cylindrical, frustum-shaped, or pyramidal electric field coupling mechanisms, the airborne end of the coupling mechanism of this invention is installed at the bottom of the UAV landing gear. On the one hand, it will not interfere with other functional equipment carried on the belly of the UAV, and it can also ensure that the effective space of the coupling electric field is far away from the UAV fuselage, effectively avoiding interference of the coupling electric field to the fuselage equipment when the system is working. On the other hand, the coupling mechanism of this invention has a larger lateral offset tolerance range, stronger anti-offset capability, and stronger structural compatibility, and can be installed on UAV landing gears of various shapes such as ring type, crossbar type, and horizontal bar type.

[0047] 3. Compared with magnetic field coupling type wireless power transmission coupling mechanism, the metal plate of the coupling mechanism of the present invention is made of aluminum material. The coupling mechanism is lightweight, easy to manufacture and easy to install on the bottom of the drone landing gear. It can ensure uninterrupted power transmission of the drone wireless charging system even when there are metal conductors in the middle or around the coupling mechanism. In addition, no eddy current loss is generated in the surrounding metal conductors when the system is working, and the electromagnetic interference to the surrounding environment is very small.

[0048] 4. Apart from the airborne coupling mechanism, the UAV side of the system of this invention only has a full-bridge rectifier and UAV battery load, without any other resonance compensation components, which can maximize the lightweight level of the UAV side.

[0049] 5. The power regulation and voltage conversion topology unit of the system of the present invention can provide high-frequency high-voltage excitation for the coupling mechanism, which is beneficial to reduce system loss and improve system transmission efficiency.

[0050] 6. Within the designed range of drone landing positions, the system of this invention can meet the constant voltage charging requirements of the drone battery load and ensure efficient and stable power transmission.

[0051] 7. The control method of the system of the present invention can be achieved simply by adjusting capacitor C1 and the equivalent coupling capacitor C of the coupling mechanism. p The proportional relationship is used to achieve the target output voltage of the control system. Attached Figure Description

[0052] Figure 1 A schematic diagram of a drone wireless charging system based on an electric field coupling-based lightweight anti-polarization wireless power transmission coupling mechanism provided in Embodiments 1 and 2 of the present invention;

[0053] Figure 2 This is a schematic diagram of a lightweight anti-polarization wireless power transmission coupling mechanism provided in Embodiment 1 of the present invention;

[0054] Figure 3 Provided for Embodiment 1 of the present invention Figure 2 A schematic diagram of the airborne end structure of the wireless power transmission coupling mechanism;

[0055] Figure 4 Provided for Embodiment 1 of the present invention Figure 2 A schematic diagram of the platform-end structure of the wireless power transmission coupling mechanism;

[0056] Among them, 1-inner circular aluminum plate; 2-outer circular aluminum plate; 3-uniformly drilled inner circular aluminum foil; 4-uniformly drilled outer circular aluminum foil; 5-first crossbar of UAV landing gear; 6-second crossbar of UAV landing gear; 7-first circular insulating plate; 8-second circular insulating plate.

[0057] Figure 5 This is a diagram illustrating the influence of different lateral offset distances on the equivalent coupling capacitance of the coupling mechanism, provided in Embodiment 1 of the present invention.

[0058] Figure 6 This is a diagram illustrating the influence of different angular offsets on the equivalent coupling capacitance of the coupling mechanism, as provided in Embodiment 1 of the present invention.

[0059] Figure 7 This is a circuit diagram of a drone wireless charging system based on an electric field coupling lightweight anti-bias wireless power transmission coupling mechanism provided in Embodiment 2 of the present invention;

[0060] Figure 8 Provided for Embodiment 2 of the present invention Figure 7 The equivalent circuit diagram;

[0061] Figure 9 Provided for Embodiment 2 of the present invention Figure 8 Equivalent circuit diagram of T-type LCL;

[0062] Figure 10 Provided for Embodiment 2 of the present invention Figure 8 China Z in1 The equivalent circuit diagram of the T-type CLC network. Detailed Implementation

[0063] To make the objectives and advantages of the present invention clearer, embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0064] It should be noted that in the description of this invention, the terms "upper," "lower," "inner," "outer," etc., which indicate the direction or positional relationship, are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0065] The advantages of electric field coupling wireless charging technology indicate that it is suitable for application in the field of drone wireless charging technology. However, there is little research on its application in drone wireless charging. This embodiment designs a lightweight anti-bias wireless power transmission coupling mechanism (Embodiment 1) and a drone wireless charging system and its control method based on the lightweight anti-bias wireless power transmission coupling mechanism using electric field coupling (Embodiment 2).

[0066] Example 1

[0067] A lightweight, anti-biased wireless power transmission coupling mechanism is disclosed. This mechanism is lightweight, low-cost, and easy to manufacture, significantly improving the utilization rate of metal plate coupling. It features 360° anti-biasing and strong lateral anti-biasing capabilities, strong structural compatibility, and does not interfere with the carrying of other functional equipment on the belly of the UAV. A schematic diagram of its structure is shown below. Figure 2 As shown. The coupling mechanism includes a large platform end and a small airborne end. A schematic diagram of the platform end structure of the coupling mechanism is shown below. Figure 4 As shown, the schematic diagram of the airborne end structure of the coupling mechanism is as follows. Figure 3 As shown.

[0068] The platform end includes an inner circular aluminum plate 1, an outer circular aluminum plate 2, and a first circular insulating plate 7, wherein the inner circular aluminum plate 1 and the outer circular aluminum plate 2 cover the upper surface of the first circular insulating plate 7; the airborne end includes a uniformly drilled inner circular aluminum foil 3, a uniformly drilled outer circular aluminum foil 4, and a second circular insulating plate 8, wherein the uniformly drilled inner circular aluminum foil 3 and the uniformly drilled outer circular aluminum foil 4 cover the lower surface of the second circular insulating plate 8.

[0069] The platform end of the coupling mechanism is installed on the ground or on a UAV take-off and landing platform, while the airborne end of the coupling mechanism is installed between the first crossbar 5 and the second crossbar 6 at the bottom of the UAV landing gear. It is far away from the fuselage equipment, does not occupy the UAV's belly space, and does not affect the normal operation of the UAV and its belly equipment.

[0070] The outer surfaces of the inner circular aluminum plate 1, the outer circular aluminum plate 2, the uniformly drilled inner circular aluminum foil 3, and the uniformly drilled outer circular aluminum foil 4 are all provided with a thin insulating layer to avoid direct contact between the metal plates, thus preventing potential system collapse and other hazards.

[0071] The radius of the inner circular aluminum plate 1 is 10-30 mm larger than the radius of the uniformly drilled inner circular aluminum foil 3. The inner ring radius of the outer circular aluminum plate 2 is 10-30 mm smaller than the inner ring radius of the uniformly drilled outer circular aluminum foil 4. The outer ring radius of the outer circular aluminum plate 2 is 10-30 mm larger than the outer ring radius of the uniformly drilled outer circular aluminum foil 4. This ensures that when the UAV experiences a 360° angular shift in its landing position and a certain range of lateral shift, the airborne end of the coupling mechanism remains within the effective electric field coupling region, ensuring stable energy transmission of the system.

[0072] The second disc-shaped insulating plate 8 is made of a thin insulating material (in this embodiment, a thin acrylic plate is used). In addition, the second disc-shaped insulating plate 8 can also be made lightweight by drilling holes, which can further reduce the weight of the airborne end of the coupling mechanism and reduce the wind resistance during the take-off and landing of the UAV.

[0073] The inner circular aluminum plate 1 and the uniformly drilled inner circular aluminum foil 3 are coupled together to form a coupling capacitance C. p1 The outer circular aluminum plate 2 and the uniformly drilled outer circular aluminum foil 4 are coupled to form a coupling capacitor C.p2 The equivalent coupling capacitance of the coupling mechanism can be calculated as C. p =C p1 C p2 / (C p1 +C p2 When the system is working, the inner circular aluminum plate 1, the uniformly drilled inner circular aluminum foil 3, the outer circular aluminum plate 2, and the uniformly drilled outer circular aluminum foil 4 are connected to the system circuit and complete the transmission of wireless power under the action of the alternating electric field.

[0074] To facilitate production, calculation, and achieve lightweighting of the airborne end of the coupling mechanism, in this embodiment, the inner disc aluminum plate 1 and the outer ring aluminum plate 2 have the same thickness, and the uniformly drilled inner disc aluminum foil 3 and the uniformly drilled outer ring aluminum foil 4 have the same thickness.

[0075] In other embodiments, the inner circular aluminum plate 1, the outer circular aluminum plate 2, the uniformly drilled inner circular aluminum foil 3, and the uniformly drilled outer circular aluminum foil 4 can adopt other structures and combinations thereof, such as rectangular, rectangular ring, elliptical, elliptical ring, etc. These are all variations on the structural design disclosed in this embodiment, but the lightweight level, angular offset resistance, lateral offset resistance, and coupling utilization rate of the metal electrode plates are reduced compared to this embodiment.

[0076] Simulation verification of the lightweight and anti-displacement properties of the coupling mechanism of this invention:

[0077] Based on the landing gear dimensions of a certain UAV and the principle of equal area division of the airborne metal plate of the coupling mechanism, a set of specific dimensions of the coupling mechanism were designed, as shown in Table 1. Combining practical application experience, the gap between the platform end and the airborne end metal plate was set to 4mm, the thickness of the platform end aluminum plate was set to 1mm, and the thickness of the airborne end aluminum foil was set to 0.1mm. The coupling mechanism is required to achieve 360° anti-offset and lateral anti-offset within a range of ±20mm.

[0078] Table 1 Main structural parameters of the coupling mechanism

[0079]

[0080] Based on the specific dimensions of the coupling mechanism in Table 1, a simulation model of the mechanism was built in COMSOL, and simulation was performed to obtain the coupling capacitance C of the coupling mechanism. p1 Coupling capacitor C p2 and equivalent coupling capacitance C p . Figure 5 The coupling capacitance C of the airborne end of the coupling mechanism under different lateral offset conditions. p1 Coupling capacitor C p2 and equivalent coupling capacitance C p The changes, Figure 6The coupling capacitance C of the airborne end of the coupling mechanism under different angular offset conditions. p1 Coupling capacitor C p2 and equivalent coupling capacitance C p The changes.

[0081] Based on simulation model measurements, the geometric volume of the aluminum foil at the airborne end of the coupling mechanism is 2.95 cm³. 3 The metallic density of aluminum is 2.7 g / cm³. 3 This means that the weight of the airborne aluminum foil is only 8g, which has minimal impact on the drone's payload, thus achieving lightweighting of the airborne coupling mechanism.

[0082] according to Figure 5 and Figure 6 Simulation results show that when the coupling mechanism experiences a 360° angular shift or a lateral shift within ±20mm, its coupling capacitance C... p1 Coupling capacitor C p2 and equivalent coupling capacitance C p The value remains almost unchanged, indicating that the coupling mechanism has strong anti-displacement capability.

[0083] The coupling mechanism designed based on the principle of electric field coupling in this embodiment has the following advantages: 1) The uniform drilling of the aluminum foil at the airborne end of the coupling mechanism fully utilizes the edge effect of the charge distribution of the metal plates, improving the coupling utilization rate of the metal plates and achieving lightweighting of the airborne end of the coupling mechanism. 2) The platform end and airborne end of the coupling mechanism are circular and their dimensions are "large to small," which can ensure that the UAV can tolerate a 360° angular deviation and a certain range of lateral offset when landing for wireless charging. 3) The coupling mechanism is lightweight, low-cost, easy to manufacture, and has strong structural compatibility, and can be installed on UAV landing gear of various shapes such as ring type, crossbar type, and horizontal bar type. 4) The airborne end of the coupling mechanism is fixed to the bottom of the UAV landing gear, away from the belly of the UAV, which will not affect the installation of functional equipment on the belly of the UAV, and can also ensure that the space in which the coupling electric field acts is far away from the UAV fuselage, effectively reducing the impact of alternating electric field on the fuselage equipment. 5) When the UAV is wirelessly charging, if there are metal conductors between the coupling mechanisms or in the surrounding environment, no eddy current loss will be generated in the metal conductors, resulting in minimal electromagnetic interference to the surrounding environment.

[0084] Example 2

[0085] To further achieve lightweight design of the UAV side structure and meet the constant voltage charging requirements of the UAV battery load, this embodiment provides a UAV wireless charging system and its control method based on a lightweight anti-bias wireless power transmission coupling mechanism using electric field coupling, according to Embodiment 1. A schematic diagram of the system is shown below. Figure 1As shown. The system includes the coupling mechanism, platform-side circuitry, and airborne-side circuitry as described in Embodiment 1. The platform-side circuitry includes a DC power supply, a full-bridge inverter, and a power regulation and voltage conversion topology unit connected in sequence. The airborne-side circuitry includes a full-bridge rectifier and a UAV battery load connected in sequence. The full-bridge inverter consists of four MOSFETs (S1 to S4), and the full-bridge rectifier consists of V... D1 ~V D4 It consists of four diodes. The power regulation and voltage conversion topology unit includes inductors L1 and L2, capacitors C1 and C2. Inductors L1 and C2 are sequentially connected between the first connection terminal of the full-bridge inverter and the inner circular aluminum plate 1. Capacitor C1 is connected between the common connection terminal of inductors L1 and C2 and the outer circular aluminum plate 2. Inductor L2 is connected between the common connection terminal of capacitor C2 and the inner circular aluminum plate 1 and the outer circular aluminum plate 2. The outer circular aluminum plate 2 is connected to the second connection terminal of the full-bridge inverter. The uniformly drilled inner circular aluminum foil 3 and the uniformly drilled outer circular aluminum foil 4 are respectively connected to the first connection terminal and the second connection terminal of the full-bridge rectifier. The value of capacitor C2 is set as the equivalent coupling capacitance C of the coupling mechanism. p k times, where k>1.

[0086] The control method of the drone wireless charging system of the present invention:

[0087] S1: Figure 7 The circuit diagram of the wireless charging system for the UAV of this invention is shown below. A simplified analysis is performed using the fundamental frequency approximation method. The simplified equivalent circuit diagram is as follows: Figure 8 As shown, the inverter output voltage It can be represented as:

[0088]

[0089] Among them, E DC ω is the system's DC input voltage, and ω is the system's operating angular frequency.

[0090] S2: Equivalent impedance R before rectification on the airborne side of the system eq for:

[0091]

[0092] S3: Z-axis of the equivalent circuit of a drone wireless charging system in1 The network can be equivalent to an inductor L m With a resistor R m A series network, so the system circuit can be equivalent to a T-LCL network, such as Figure 9 As shown. Ignoring the losses of reactive components in the circuit, the circuit Z of the drone wireless charging system can be calculated using circuit principles. in1 The input impedance of the network is:

[0093] Z in1 =R m +jωL m (1)

[0094] in,

[0095] In the formula, ω is the system's operating angular frequency.

[0096] S4: Write the KVL equations for the equivalent T-LCL network:

[0097]

[0098] S5: When the resonance relationship is satisfied Then, the current gain G1 and input impedance Z1 of the T-LCL network can be obtained:

[0099]

[0100] As can be seen from equation (4), under constant voltage input conditions, the system output current is Only with input voltage The capacitor C1 is related to the resonant angular frequency ω and is independent of the load size. This T-LCL network has constant voltage input and constant current output characteristics, and the system input impedance is purely resistive. The system operates in a zero phase angle input state and has a high power factor.

[0101] S6: At this point, the Z-axis of the equivalent circuit of the drone's wireless charging system... in1 The network can be equivalently represented as a T-CLC network with a constant current source input, such as... Figure 10 As shown.

[0102] Write the KVL equations for a T-CLC network with constant current source input:

[0103]

[0104] S7: When the resonance relationship is satisfied Then, the voltage gain G2 of the T-CLC network can be obtained:

[0105]

[0106] S8: The output voltage gain G3 of the drone wireless charging system can be calculated from equations (4) and (6):

[0107]

[0108] As can be seen from equation (7), the output voltage of the drone wireless charging system is... Only with input voltage Capacitor C1 and the equivalent coupling capacitance C of the coupling mechanismp Regarding input voltage With capacitor C1 being a constant parameter, and the airborne end of the coupling mechanism of this invention experiencing a 360° angular shift and a lateral shift within the range of 10-30mm, the airborne end can still remain entirely within the effective coupling area. The equivalent coupling capacitor C p The voltage remains almost constant, thus the system possesses constant voltage input and constant voltage output characteristics. Furthermore, this can be achieved simply by adjusting capacitor C1 and the equivalent coupling capacitance C of the coupling mechanism. p By establishing the proportional relationship, the target output voltage of the control system can be achieved.

[0109] The UAV wireless charging system and its control method based on a lightweight anti-bias wireless power transmission coupling mechanism using electric field coupling provided in this embodiment have the following advantages: 1) The UAV side of the system, apart from the airborne end of the coupling mechanism, only has a rectifier and the UAV battery load, without other resonant compensation components, which maximizes the lightweight level of the UAV side and is conducive to the promotion and application of UAV wireless charging technology; 2) When the airborne end of the coupling mechanism deviates within the design specifications, the system has constant voltage input and constant voltage output characteristics, which can ensure efficient and stable transmission of system power. This can be achieved by simply adjusting capacitor C1 and the equivalent coupling capacitor C of the coupling mechanism. p The proportional relationship is used to achieve the target output voltage of the control system.

[0110] The technical solution of the present invention has been described in conjunction with the embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions resulting from such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. An unmanned aerial vehicle wireless charging system based on a lightweight bias- resistant wireless power coupling mechanism based on electric field coupling, characterized in that: The application relates to a lightweight anti-deviation wireless power transmission coupling mechanism, a platform-side circuit and an airborne-side circuit. The inner disc aluminum plate and the outer ring aluminum plate are covered on the upper surface of the first disc-shaped insulating plate, and the uniformly-drilled inner disc aluminum foil and the uniformly-drilled outer ring aluminum foil are covered on the lower surface of the second disc-shaped insulating plate. The platform-side circuit comprises a direct-current power supply, a full-bridge inverter, a power regulation and voltage conversion topology unit which are sequentially connected, and the airborne-side circuit comprises a full-bridge rectifier and a UAV battery load which are sequentially connected. The power regulation and voltage conversion topology unit comprises an inductor L1, an inductor L2, a capacitor C1 and a capacitor C2. The inductor L1 and the capacitor C2 are sequentially connected between the first connecting end of the full-bridge inverter and the inner disc aluminum plate, the capacitor C1 is connected between the common connecting end of the inductor L1 and the capacitor C2 and the outer ring aluminum plate, the inductor L2 is connected between the common connecting end of the capacitor C2 and the inner disc aluminum plate and the outer ring aluminum plate, and the second connecting end of the full-bridge inverter is connected with the outer ring aluminum plate. The uniformly-drilled inner disc aluminum foil and the uniformly-drilled outer ring aluminum foil are respectively connected with the first connecting end of the full-bridge rectifier and the second connecting end of the full-bridge rectifier. The inner disc aluminum plate and the uniform-drilling inner disc aluminum foil are coupled to form a coupling capacitor C p1 The outer ring aluminum plate and the uniform-drilling outer ring aluminum foil are coupled to form a coupling capacitor C p2 The equivalent coupling capacitor of the coupling mechanism can be calculated as When the system works, a coupling electric field is established among the inner disc aluminum plate, the uniform-drilling inner disc aluminum foil, the outer ring aluminum plate and the uniform-drilling outer ring aluminum foil, and wireless electric energy transmission to the unmanned aerial vehicle battery load is completed under the action of the coupling electric field. The unmanned aerial vehicle wireless charging system based on the lightweight anti-bias wireless power coupling mechanism of the electric field coupling adopts a fundamental approximation method for simplified analysis, and the inverter output voltage is: ； wherein is the system DC input voltage, is the system operating angular frequency; System on board side equivalent impedance before rectification is: ； Z of the equivalent circuit of the unmanned aerial vehicle wireless charging system in1 The network is equivalent to an inductor L m In series with a resistor R m The system circuit is equivalent to a T-LCL network, ignoring the loss of reactive elements in the circuit, and the circuit Z of the unmanned aerial vehicle wireless charging system can be calculated by using circuit principle in1 The input impedance of the network is: （1） wherein (2) In the formula is the system angular frequency; KVL equations are written for the equivalent T-LCL network: （3） When the resonance relationship is satisfied, the T-LCL network current gain and input impedance are: （4） From equation (4), it can be seen that under the condition of constant voltage input, the system output current is only related to the input voltage , the capacitance and the resonant angular frequency , and is independent of the load size. The T-LCL network has constant voltage input and constant current output characteristics, the system input impedance is purely resistive, the system has a high power factor, and the transmission of electric energy is efficient and stable. At this time, the equivalent circuit of the unmanned aerial vehicle wireless charging system is The network is equivalent to a T-CLC network with a constant current source input; KVL equations are written for the T-CLC network with constant current source input: （5） When the resonance relationship is satisfied, the T-CLC network voltage gain is: （6） The output voltage gain of the unmanned aerial vehicle wireless charging system can be calculated from formula (4) and formula (6) : （7） From formula (7), the output voltage of the unmanned aerial vehicle wireless charging system is related to the input voltage , the capacitance and the equivalent coupling capacitance of the coupling mechanism . When the on-board end of the coupling mechanism has a 360° angular offset and a lateral offset within a range of 10-30 mm, the on-board end can still be entirely within the effective coupling region, and the equivalent coupling capacitance is almost unchanged. The system can achieve efficient and stable power transmission to the battery load of the unmanned aerial vehicle. By adjusting the proportional relationship between the capacitance and the equivalent coupling capacitance of the coupling mechanism , the target output voltage of the system can be achieved. 2.The UAV wireless charging system based on the lightweight anti-offset wireless power coupling mechanism of electric field coupling according to claim 1, wherein, The platform end is installed on the ground or a UAV take-off and landing platform, and the airborne end is installed between the two horizontal rods at the bottom of a UAV landing gear. 3.The UAV wireless charging system based on the lightweight anti-offset wireless power coupling mechanism of electric field coupling of claim 1, wherein, The outer surfaces of the inner disc aluminum plate, the outer ring aluminum plate, the uniformly-drilled inner disc aluminum foil and the uniformly-drilled outer ring aluminum foil are provided with light and thin insulating isolation layers. 4.The UAV wireless charging system based on the lightweight anti-offset wireless power coupling mechanism of electric field coupling according to claim 3, wherein, The radius of the inner disc aluminum plate is 10-30mm larger than that of the uniformly-drilled inner disc aluminum foil. 5.The UAV wireless charging system based on the lightweight anti-offset wireless power coupling mechanism of electric field coupling according to claim 3, wherein, The inner ring radius of the outer ring aluminum plate is 10-30mm smaller than that of the uniformly-drilled outer ring aluminum foil. 6.The UAV wireless charging system based on the lightweight anti-offset wireless power coupling mechanism of electric field coupling of claim 3, wherein, The outer ring radius of the outer ring aluminum plate is 10-30mm larger than that of the uniformly-drilled outer ring aluminum foil.

7. The unmanned aerial vehicle wireless charging system based on the lightweight anti-offset wireless power coupling mechanism of electric field coupling of claim 1, wherein The second disc-shaped insulating plate is made of light and thin insulating material. 8.The UAV wireless charging system based on the lightweight anti-offset wireless power coupling mechanism of electric field coupling of claim 1, wherein: The value of the capacitor C2 is k times the equivalent coupling capacitance C of the coupling mechanism, k > 1. p The value of the capacitor C2 is k times the equivalent coupling capacitance C of the coupling mechanism, k > 1.

Images