Unmanned aerial vehicle anti-offset wireless charging system based on concentric encircling type coupling mechanism

Abstract

The invention provides an unmanned aerial vehicle anti-offset wireless charging system based on a concentric encircling type coupling mechanism. The system is used for solving the problems that an existing EC-WPT system is weak in anti-offset capability and complex in control. Comprising a transmitting end and a receiving end, the transmitting end comprises a first hemispherical polar plate and an annular polar plate which are coaxially arranged, and the bottom end of the first hemispherical polar plate is located in the annular polar plate; the receiving end comprises a second hemispherical pole plate and an arc-shaped pole plate which are coaxially arranged, during wireless charging, the arc-shaped pole plate and the annular pole plate are arranged oppositely, and the first hemispherical pole plate is sleeved with the second hemispherical pole plate. According to the concentric surrounding type coupling mechanism, the problem of horizontal offset sensitivity of an existing electric field coupling mechanism is solved through gravity, the effect of coping with the rotation offset problem is good, the anti-offset capacity is improved, the main coupling capacitance of the coupling mechanism is large, and the transmission performance of a circuit can be effectively improved; and the cross coupling capacitance is extremely small, so that the interference on electric energy transmission is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the field of wireless power transmission, and in particular to an anti-drift wireless charging system for unmanned aerial vehicles based on a concentric embracing coupling mechanism. Background Art

[0002] Unmanned aerial vehicle (UAV) technology has become deeply integrated into many aspects of daily life and production, with its applications in military reconnaissance, commercial logistics, agricultural plant protection, and other fields continuously expanding. However, the energy limitations of onboard batteries, resulting in short flight times, have become a core bottleneck hindering the realization of long-term, highly autonomous operations. Traditional contact-based charging or manual battery replacement solutions are limited by cumbersome operation, easily worn interfaces, and inability to adapt to harsh environments. These solutions are unable to meet the requirements of future swarming, all-weather, and fully autonomous UAV operations.

[0003] To overcome this bottleneck, wireless power transfer (WPT) technology offers an attractive solution. Among mainstream WPT technologies, electric-field coupled wireless power transfer (EC-WPT), whose coupling mechanism consists of lightweight metal plates, offers inherent advantages such as light weight, low cost, no eddy current heating of surrounding metal objects, and excellent electromagnetic compatibility. This makes it highly compatible with the lightweight and highly integrated design requirements of drones. Deploying an EC-WPT system on a takeoff and landing platform enables automatic energy replenishment, significantly improving operational efficiency and autonomy. However, the performance of an EC-WPT system is highly sensitive to the alignment accuracy of its coupling mechanism. During autonomous landing, drones inevitably experience multi-dimensional deviations, including horizontal and angular, due to factors such as airflow disturbances and GPS positioning errors. With traditional parallel-plate structures, even slight deviations can lead to a sharp drop in mutual capacitance, resulting in a drastic drop in transmission power and efficiency.

[0004] To address these issues, existing research focuses on two main aspects. First, at the physical coupling mechanism level, researchers are working to design structures with inherent anti-misalignment capabilities. Parallel plate structures, as the most basic structure, are extremely sensitive to any form of misalignment. Even slight misalignment can lead to a sharp drop in mutual capacitance, resulting in a drastic drop in transmission power and efficiency. Separate circular / ring-shaped structures proposed in existing research can effectively address rotational misalignment, but their resistance to lateral misalignment remains weak. Cylindrical structures are ideal for rotating equipment, enabling stable 360° energy transmission without blind spots. However, their poor tolerance to lateral misalignment and bulky structure make them unsuitable for free-fall drones. To address the "blind spot" issue of rotational misalignment, researchers have proposed reconfigurable enhanced quadrupole plates / square-shaped emitter plates. These plates can be switched between different combinations using electronic switches to accommodate arbitrary rotational angles of the drone. While this solution offers superior performance, it requires a relatively complex switch matrix control system, resulting in complex structure and control, and high cost.

[0005] At the resonant compensation topology and circuit level, researchers have designed a variety of networks to improve system performance. By adding resonant elements such as high-order compensation topologies (such as LCL-L / LCLC), more design freedom is provided, which can achieve high-power transmission and load-independent output characteristics. However, its disadvantage is that the circuit analysis and parameter adjustment process is relatively complicated, and some design schemes still retain components such as resonant inductors at the receiving end (airborne side), which is contrary to the goal of pursuing extreme lightweight for drones. A major advantage of the F-type compensation topology is that it can rely on the network's own characteristics to avoid current shocks and achieve safe transient response when the load (drone) moves in and out. However, its disadvantages are also quite obvious, that is, it does not have voltage gain capability, which limits the power transmission level of the system to a certain extent. Summary of the Invention

[0006] The purpose of the present invention is to provide a UAV anti-drift wireless charging system based on a concentric embracing coupling mechanism, which is used to solve the technical problems of weak anti-drift capability and complex control of existing EC-WPT systems.

[0007] A UAV anti-drift wireless charging system based on a concentric embracing coupling mechanism includes a transmitting end and a receiving end. The transmitting end includes a first hemispherical plate and an annular plate coaxially arranged, and the bottom end of the first hemispherical plate is located inside the annular plate.

[0008] The receiving end includes a second hemispherical plate and an arc-shaped plate that are coaxially arranged, and both the first hemispherical plate and the second hemispherical plate are hollow structures.

[0009] Optionally, the arc-shaped electrode plate includes two fan-shaped electrode plates arranged in parallel;

[0010] The two fan-shaped ring plates are arranged rotated 180 degrees. The fan-shaped ring plate and the second hemispherical plate are arranged coaxially. The bottom end of the second hemispherical plate is located between the two fan-shaped ring plates.

[0011] Optionally, during wireless charging, the arc-shaped electrode plate and the annular electrode plate are arranged opposite each other, and the second hemispherical electrode plate is sleeved on the first hemispherical electrode plate.

[0012] Optionally, the transmitting end includes a DC power supply, a high-frequency inverter and a resonance compensation circuit connected in sequence, and the first hemispherical plate and the annular plate are respectively connected to two output ends of the resonance compensation circuit.

[0013] Optionally, the receiving end includes a high-frequency rectifier, a filter capacitor and a load;

[0014] One end of the second hemispherical plate is connected to an input end of the high-frequency rectifier, one end of the two fan-shaped plates in parallel is connected to the other input end of the high-frequency rectifier, and the two ends of the filter capacitor in parallel with the load are respectively connected to the two output ends of the high-frequency rectifier.

[0015] Optionally, the resonant compensation circuit includes a first resonant inductor, a second resonant inductor, a third resonant inductor, a first resonant capacitor, and a second resonant capacitor;

[0016] One end of the first resonant inductor, the second resonant inductor and the first resonant capacitor are connected to each other, the other ends of the first resonant inductor and the first resonant capacitor are respectively connected to the two output ends of the high-frequency rectifier, the other end of the second resonant inductor is connected to one end of the second resonant capacitor, the other end of the second resonant capacitor is connected to one end of the third resonant inductor and then to the annular plate, and the other end of the third resonant inductor is connected to the other end of the first resonant capacitor and then to the first hemispherical plate.

[0017] Optionally, when the transmitter and receiver are coupled, the total input impedance of the system is Z in2 for:

[0018]

[0019] Where L1, L2 and L3 are the self-inductance values ​​of the first, second and third resonant inductors respectively, C1 is the capacitance value of the first resonant capacitor, R eq is the equivalent resistance of the load, ω is the system angular frequency, C S is the coupling capacitor, where: C S =C2, C2 is the capacitance value of the second resonant capacitor.

[0020] Optionally, when the transmitter and receiver are coupled, the system voltage gain G v for:

[0021]

[0022] Where U out is the effective value of the output voltage on the load, U in is the effective value of the fundamental voltage output by the inverter, L1 and L3 are the self-inductance values ​​of the first and third resonant inductors respectively, ω is the system angular frequency, C S is the coupling capacitor, where: C S =C2, C2 is the capacitance value of the second resonant capacitor.

[0023] Optionally, when the transmitter and receiver are far apart, the total input impedance of the system is Z in2 for:

[0024]

[0025]

[0026] Where L1 and L2 are the self-inductance values ​​of the first and second resonant inductors respectively, C1 is the capacitance value of the first resonant capacitor, and ω is the system angular frequency. According to the resonant condition of the resonant compensation circuit, it can be known that: ω 2 C1L2=1,Z in2 tends to infinity.

[0027] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0028] 1. The main coupling capacitance of the concentric encircling coupling mechanism proposed in this application is large, which can effectively improve the transmission performance of the circuit; its cross-coupling capacitance is extremely small, which significantly reduces the interference with power transmission.

[0029] 2. The concentric embracing coupling mechanism of the present application utilizes gravity to solve the problem of horizontal offset sensitivity of previous electric field coupling mechanisms, and has a better effect on the problem of rotational offset, thereby improving the anti-offset capability.

[0030] 3. The dual-T resonant topology of the present application is well matched with the coupling mechanism, which not only simplifies the secondary circuit but also realizes the low-power standby function.

[0031] 4. In this application, all compensation components such as resonant inductors and capacitors are designed at the transmitting end. The drone's onboard receiving end only needs to be equipped with a lightweight receiving plate and rectifier filter circuit, which greatly reduces the flight load.

[0032] 5. In this application, when the drone flies away, the input impedance of the system will naturally become extremely high, causing the system to automatically enter a safe low-power standby state without the need for any additional detection and control circuits.

[0033] 6. The topology of this application can achieve constant voltage output and is not affected by changes in the back-end battery load state, making it very suitable for charging applications.

[0034] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings of the present invention are described below.

[0036] Figure 1 It is a schematic diagram of the three-dimensional structure of the concentric embracing coupling mechanism of the present invention.

[0037] Figure 2 It is a plan view of the concentric embracing coupling mechanism of the present invention.

[0038] Figure 3 This is a simulated cloud diagram of the electric field strength of the concentric encircling coupling mechanism of the present invention.

[0039] Figure 4 This is a graph showing how the coupling capacitance of the present invention changes with the rotation angle.

[0040] Figure 5 This is a circuit diagram of the anti-drift wireless charging system for drones of the present invention.

[0041] Figure 6 This is the equivalent circuit diagram of the drone of the present invention when it moves in.

[0042] Figure 7 This is the equivalent circuit diagram of the drone of the present invention when it is moved out.

[0043] Figure 8 This is a voltage curve diagram without rectifier load in the simulation of the present invention.

[0044] Figure 9 This is a load voltage curve diagram after rectification in the simulation of the present invention.

[0045] Figure 10 This is a voltage curve diagram when the load changes in the simulation of the present invention.

[0046] Figure 11 This is a macro output curve diagram of voltage and current of the high frequency inverter simulated in the present invention.

[0047] Figure 12 This is a microscopic output curve diagram of voltage and current of a high-frequency inverter in the simulation of the present invention.

[0048] In the figure: P1-annular plate; P2-first hemispherical plate; P3-arc-shaped plate; P4-second hemispherical plate. DETAILED DESCRIPTION

[0049] The present invention will be further described below with reference to the accompanying drawings and examples.

[0050] Example 1:

[0051] like Figure 1 and Figure 2 A concentric embracing coupling mechanism shown includes a transmitting end and a receiving end. The transmitting end includes a first hemispherical plate P2 and an annular plate P1 that are coaxially arranged. The bottom end of the first hemispherical plate P2 is located inside the annular plate P1.

[0052] The receiving end includes a coaxially arranged second hemispherical plate P4 and an arc-shaped plate P3. The first hemispherical plate P2 and the second hemispherical plate P4 are both hollow structures.

[0053] like Figure 1 and Figure 2 As shown, the arc-shaped plate P3 includes two fan-shaped plates arranged in parallel;

[0054] The two fan-shaped ring plates are rotated 180 degrees and are coaxially arranged with the second hemispherical plate P4. The bottom end of the second hemispherical plate P4 is located between the two fan-shaped ring plates.

[0055] like Figure 1 and Figure 2 As shown, during wireless charging, the arc-shaped electrode plate P3 is arranged opposite to the annular electrode plate P1, and the second hemispherical electrode plate P4 is sleeved on the first hemispherical electrode plate P2.

[0056] In this embodiment, the inner wall of the second hemispherical plate P4 is gap-fitted with the outer wall of the first hemispherical plate P2. The concentric embracing coupling mechanism of the present application is simulated and analyzed by the finite element simulation software Maxwell. The specific parameters are shown in Table 1. In Table 1, r1 is the radius of the bottom end of the first hemispherical plate P2, r2 is the radius of the inner circle of the annular plate P1, r3 is the radius of the outer circle of the annular plate P1, r4 is the radius of the bottom end of the second hemispherical plate P4, l1 is the width of the arc plate P3, and l2 is the height of the second hemispherical plate P4. The electric field distribution of the coupling mechanism can be obtained through simulation analysis as shown in Table 1. Figure 3 As shown, and the safety distance is given in the figure. Figure 3 (a), 3(a), 3(a), and 3(a) are the simulated cloud images of the X0Y plane, X0Z plane, Y0Z plane, and the Y0Z plane when the receiver is rotated 45°, respectively. The simulated cloud images show that the field strength on the XYZ planes begins to decay beyond 240 mm, indicating a relatively short safety distance.

[0057] Table 1 Coupling mechanism parameters

[0058]

[0059] In this embodiment, the design of the first hemispherical plate P2 at the transmitter and the second hemispherical plate P4 at the receiver allows the coupling mechanism to have greater capacitance, achieving positive feedback on transmission efficiency. Furthermore, during coupled charging, gravity allows the drone to automatically return to its correct position even if its landing point shifts. The dual-fan ring plate configuration allows the drone to maintain normal charging even during 360-degree rotation. Through appropriate parameter design, the two main coupling capacitors formed by the plates can be made equal, maximizing the overall equivalent capacitance.

[0060] like Figure 4 As shown, Figure 4 (a) is a graph showing the change of the main coupling capacitance with the rotation angle. Figure 4 In (a), C13 is the coupling capacitance between the arc-shaped plate P3 and the annular plate P1, and C24 is the coupling capacitance between the first hemispherical plate P2 and the second hemispherical plate P4. Figure 4 (b) is a graph showing the cross-coupling capacitance changes with the rotation angle. Figure 4 In (b), C12 is the cross-coupling capacitor between the annular plate P1 and the first hemispherical plate P2, C14 is the cross-coupling capacitor between the annular plate P1 and the second hemispherical plate P4, C32 is the cross-coupling capacitor between the arc-shaped plate P3 and the first hemispherical plate P2, and C34 is the cross-coupling capacitor between the arc-shaped plate P3 and the second hemispherical plate P4.

[0061] Depend on Figure 4 (a) shows that at different angles, the main coupling capacitance is around 765pF, which has little impact on the transmission performance of the circuit. Figure 4 (b) It can be seen that at different angles, the cross capacitance of the coupling mechanism is extremely small, with the maximum not exceeding 10pF and the minimum reaching about 1pF, which is much smaller than the main coupling capacitance. It has little impact on the overall transmission performance and can ensure the stability of energy transmission, which is difficult to achieve with traditional planar structures.

[0062] Example 2:

[0063] like Figure 5 The anti-drift wireless charging system for a drone based on a concentric embracing coupling mechanism shown includes the concentric embracing coupling mechanism described in Example 1, wherein the second hemispherical plate P4 and the arc-shaped plate P3 are embedded and installed on the bottom of the drone, and the first hemispherical plate P2 and the annular plate P1 are installed in the drone slot;

[0064] The transmitting end also includes a DC power supply U dc , a high-frequency inverter and a resonant compensation circuit, wherein the first hemispherical plate P2 and the annular plate P1 are respectively connected to the two output ends of the resonant compensation circuit.

[0065] The receiving end also includes a high-frequency rectifier, a filter capacitor C f and load R L One end of the second hemispherical plate P4 is connected to an input end of the high-frequency rectifier, and one end of the two fan-shaped plates is connected in parallel to the other input end of the high-frequency rectifier. The filter capacitor C f The two ends connected in parallel with the load are respectively connected to the two output ends of the high-frequency rectifier.

[0066] In this embodiment, the DC power supply U dc The two ends of are respectively connected to the two input ends of the high-frequency inverter, the high-frequency inverter includes a full-bridge inverter composed of four MOS tubes S1-S4, the high-frequency rectifier includes a rectifier inverter composed of four diodes D1-D4, and the resonant compensation circuit includes a first resonant inductor L1, a second resonant inductor L2, a third resonant inductor L3, a first resonant capacitor C1 and a second resonant capacitor C2;

[0067] One end of the first resonant inductor L1, the second resonant inductor L2, and the first resonant capacitor C1 are connected to each other. The other ends of the first resonant inductor L1 and the first resonant capacitor C1 are respectively connected to the two output ends of the high-frequency rectifier. The other end of the second resonant inductor L2 is connected to one end of the second resonant capacitor C2. The other end of the second resonant capacitor C2 is connected to one end of the third resonant inductor L3 and then to the annular plate P1. The other end of the third resonant inductor L3 is connected to the other end of the first resonant capacitor C1 and then to the first hemispherical plate P2.

[0068] In this embodiment, if Figure 6 As shown, when the drone lands in place, the coupling capacitor C S The access circuit starts working and the system is in the charging state. The equivalent circuit at this time is a complete double T-type resonant network. The first resonant inductor L1, the second resonant inductor L2 and the first resonant capacitor C1 in the resonant compensation circuit form a T-type LCL network. C2, L3 and C S The T-type CLC network consists of: S is the coupling capacitance C of the concentric encircling coupling mechanism S =C 13 +C 23 .

[0069] Analysis of system ZPA operation:

[0070] The equivalent circuit of the secondary network and its load is as follows Figure 6 As shown, Figure 6 Middle R eq is the load R L The equivalent resistance of the input impedance Z in1 The second resonant capacitor C2, the third resonant inductor L3, the coupling capacitor C S and the equivalent resistance R eq The decision expression is:

[0071]

[0072] By taking the common denominator of the fraction part, we can get:

[0073]

[0074] In order to simplify the impedance network characteristics, the first resonance condition is introduced, that is, L3 and C S Series resonance occurs 2 C S L3=1, we can get:

[0075]

[0076] Expand to get:

[0077]

[0078] At this time Z in1 Contains an imaginary part (generated by C2 and L3) and a real part, introducing the second resonance condition: C2 = C S We can get: ω 2 C2L3=1, further:

[0079]

[0080] The input impedance Z can be obtained in1 The final expression is:

[0081]

[0082] The total input impedance of the system is Z in2 The expression is:

[0083]

[0084] Introducing the third resonance condition ω 2 C1L2=1, and L1=L2 is often taken to obtain symmetric characteristics, which can be obtained:

[0085]

[0086] Since L1=L2 and ω 2 C1L2=1, the imaginary parts in the expression cancel each other out again, and we get:

[0087]

[0088] Finally, the total input impedance of the system is Z in2 It is also simplified to a pure resistor

[0089]

[0090] Under this condition, the system can work in ZPA state.

[0091] Load independence analysis:

[0092] The key to maintaining a stable output voltage despite varying load resistance (i.e., load independence) lies in the unique transfer characteristics of the twin-T resonant network. When operating at its designed resonant frequency, the circuit behaves as an ideal "voltage-controlled voltage source," with its voltage gain determined solely by the network's internal inductance and capacitance, independent of the size of the connected load.

[0093] In an ideal lossless resonant network, the input power P in Should be equal to the output power P out ,Right now:

[0094]

[0095] Where U out is the load R L The effective value of the output voltage on U in It is the effective value of the fundamental voltage output by the inverter.

[0096] From the above analysis, we can see that:

[0097]

[0098] Further we can get:

[0099]

[0100] It can be seen that the load resistance R on both sides of the above formula eq can be completely canceled out, we get:

[0101]

[0102] Therefore, the system voltage gain G v for:

[0103]

[0104] From the above formula, we can see that the voltage gain G v The value of is determined only by the fixed parameters of the system - the first resonant inductor L1, the third resonant inductor L3, the coupling capacitor C S and the system operating angular frequency ω. The load term R is not included at all. eq Therefore, the load independence of the twin-T resonant network mainly includes:

[0105] As long as the system works at the designed resonant frequency, no matter the back-end load R eq How does it change (for example, when the battery changes from no load to full load, its equivalent resistance will change), the output voltage U out Relative to input voltage U in The ratio is constant. At the same time, the input voltage U inUnder the premise of stability, the system can achieve constant voltage output.

[0106] Analysis of the drone's standby state after removal:

[0107] In this embodiment, when the drone flies away, the transmitter and the receiver are far away, and the coupling capacitor C S Approximately 0 (open circuit) circuit structure changes fundamentally. S After disconnection, the secondary load R eq Completely decoupled from the entire system. At this time, the inverter drive circuit becomes: the primary T-LCL network (first resonant inductor L1, second resonant inductor L2 and first resonant capacitor C1) is connected in series with the second resonant capacitor C2 and third resonant inductor L3 that originally belonged to the secondary compensation network. Its equivalent circuit is as follows: Figure 7 shown.

[0108] In the system design, the second resonant capacitor C2 and the third resonant inductor L3 meet the resonance condition: ω 2 L3C2=1(C2=C S ). The total impedance of a series LC circuit in a resonant state is:

[0109]

[0110] Therefore, the branch formed by C2 and L3 behaves as a short circuit at the operating frequency ω. Therefore, L2 and C1 form a parallel relationship, and the impedance of the parallel network is:

[0111]

[0112] According to the resonance condition of the primary network, it is known that ω 2 L2C1=1. Substituting this condition into the above formula, we can see that the denominator is 0. Therefore, the impedance of this parallel network theoretically tends to infinity. The total input impedance of the system is Z in2 The first resonant inductor L1 is connected in series with this infinite impedance:

[0113]

[0114] This input impedance tending to infinity is the key to the system's automatic standby mode. When a high-frequency inverter faces an extremely high load impedance, its output current I in =U in / Z in This allows the system to automatically enter a very low power standby mode after the drone leaves without any additional detection or control logic.

[0115] Simulation and verification:

[0116] According to the analysis of Examples 1 and 2, the coupling capacitor is connected to the system circuit. The specific parameters of the system circuit can be obtained as shown in Table 2. The system circuit is simulated and verified in Matlab as shown in Table 2. Figures 8-12 The simulation results are shown.

[0117] Table 2 Circuit Specific Parameters

[0118]

[0119] Figure 8 and Figure 9 The dynamic response of the system output voltage is shown during the simulated drone departure (load disconnection) and return (load reconnection) processes. Figure 8 is the AC load voltage before rectification, Figure 9 is the DC load voltage after rectification and filtering. As can be seen from the figure, during the period of 0-6ms, the system charges stably and the output voltage is constant; at 6ms, the load is disconnected (simulating the drone flying away), and the output voltage quickly drops to zero; at 12ms, the load is reconnected (simulating the drone returning), and the output voltage quickly returns to its previous stable value. It can be seen from the figure that after the drone is removed, the circuit is in normal operation. After the drone is moved back in, the circuit quickly operates normally again. The two figures together verify that the system has a fast, stable and safe transient response capability for the core operation of drone "take-off and landing". The system can seamlessly achieve "stop and charge" and "fly and stop (charge)", proving its robustness in practical applications.

[0120] from Figure 10 It can be seen that when the system is working stably, the back-end load resistance R eq The output voltage changes when a sudden change occurs (the figure shows a change from 6Ω to 12Ω and then back to 6Ω). It can be seen that the output voltage briefly dips at each load change, but then recovers to its pre-change stable voltage within a very short time (microseconds). This demonstrates the circuit's load-independent constant-voltage output characteristics. This proves that this wireless charging system is well-suited for charging devices such as batteries. Because a battery's equivalent internal resistance constantly changes during charging, the system's constant-voltage output ensures a stable charging voltage throughout the entire charging cycle, which is crucial for ensuring battery safety and longevity.

[0121] Figure 11 and Figure 12 The voltage and current output of the inverter are observed from macroscopic and microscopic perspectives respectively. Figure 11The image shows the changes in the high-frequency inverter's output current as the drone moves in and out. During the charging phase (0-6ms and after 12ms), the current exhibits a stable, high-amplitude sine wave envelope. During the drone's exit phase (6-12ms), the current amplitude rapidly and automatically decays to a negligible minimum. Figure 12 This is a magnified view of the inverter output waveform during charging. You can see that the zero crossing points of the current and voltage waveforms almost coincide, meaning the voltage and current are in phase. At this point, the system is operating in the zero phase angle (ZPA) state, with energy output from the inverter at maximum efficiency, minimizing unnecessary losses in the switches and circuitry. The system is operating at its optimal point.

[0122] In summary, this paper addresses the offset problem in wireless charging applications for drones by designing an EC-WPT system based on a concentric ring-shaped coupling mechanism and a dual-T resonant topology. This system achieves excellent offset resistance and lightweight airborne terminals. The proposed concentric ring-shaped coupling mechanism has a large main coupling capacitance, which effectively improves the transmission performance of the circuit; its cross-coupling capacitance is extremely small, significantly reducing interference with power transmission. The concentric ring-shaped design of the coupling mechanism utilizes gravity to resolve the horizontal offset sensitivity issue of previous electric field coupling mechanisms, and it also effectively addresses rotational offset, improving offset resistance. The dual-T resonant topology is well matched to the coupling mechanism, simplifying the secondary circuit and enabling a low-power standby function. The proposed solution provides a feasible path for solving the "last mile" problem of autonomous drone charging, combining robustness, efficiency, and lightweightness. It has important theoretical research value and broad engineering application prospects.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A UAV anti-drift wireless charging system based on a concentric ring-shaped coupling mechanism, comprising a transmitting end and a receiving end, characterized in that: The transmitting end includes a first hemispherical plate and an annular plate coaxially arranged, wherein the bottom end of the first hemispherical plate is located inside the annular plate; The receiving end includes a second hemispherical plate and an arc-shaped plate that are coaxially arranged, and both the first hemispherical plate and the second hemispherical plate are hollow structures.

2. The anti-drift wireless charging system for UAVs based on a concentric embracing coupling mechanism according to claim 1, characterized in that: The arc-shaped electrode plate includes two fan-shaped ring electrodes arranged in parallel; The two fan-shaped ring plates are arranged rotated 180 degrees. The fan-shaped ring plate and the second hemispherical plate are arranged coaxially. The bottom end of the second hemispherical plate is located between the two fan-shaped ring plates.

3. The anti-drift wireless charging system for UAVs based on a concentric embracing coupling mechanism according to claim 1 or 2, characterized in that: During wireless charging, the arc-shaped electrode plate and the annular electrode plate are arranged opposite each other, and the second hemispherical electrode plate is sleeved on the first hemispherical electrode plate.

4. The anti-drift wireless charging system for UAVs based on a concentric embracing coupling mechanism according to claim 3, characterized in that: The transmitting end includes a DC power supply, a high-frequency inverter and a resonance compensation circuit which are connected in sequence. The first hemispherical plate and the annular plate are respectively connected to two output ends of the resonance compensation circuit.

5. The anti-drift wireless charging system for UAV based on concentric embracing coupling mechanism according to claim 1, characterized in that: The receiving end includes a high-frequency rectifier, a filter capacitor and a load; One end of the second hemispherical plate is connected to an input end of the high-frequency rectifier, one end of the two fan-shaped plates in parallel is connected to the other input end of the high-frequency rectifier, and the two ends of the filter capacitor in parallel with the load are respectively connected to the two output ends of the high-frequency rectifier.

6. The anti-drift wireless charging system for UAVs based on a concentric embracing coupling mechanism according to claim 4, characterized in that: The resonant compensation circuit includes a first resonant inductor, a second resonant inductor, a third resonant inductor, a first resonant capacitor and a second resonant capacitor; One end of the first resonant inductor, the second resonant inductor and the first resonant capacitor are connected to each other, the other ends of the first resonant inductor and the first resonant capacitor are respectively connected to the two output ends of the high-frequency rectifier, the other end of the second resonant inductor is connected to one end of the second resonant capacitor, the other end of the second resonant capacitor is connected to one end of the third resonant inductor and then to the annular plate, and the other end of the third resonant inductor is connected to the other end of the first resonant capacitor and then to the first hemispherical plate.

7. The anti-drift wireless charging system for UAVs based on a concentric embracing coupling mechanism according to claim 6, characterized in that: When the transmitter and receiver are coupled, the total input impedance of the system is Z in2 for: Where L1, L2 and L3 are the self-inductance values ​​of the first, second and third resonant inductors respectively, C1 is the capacitance value of the first resonant capacitor, R eq is the equivalent resistance of the load, ω is the system angular frequency, C S is the coupling capacitor, where: C S =C2, C2 is the capacitance value of the second resonant capacitor.

8. The anti-drift wireless charging system for UAVs based on a concentric embracing coupling mechanism according to claim 6, characterized in that: When the transmitter and receiver are coupled, the system voltage gain G v for: Where U out is the effective value of the output voltage on the load, U in is the effective value of the fundamental voltage output by the inverter, L1 and L3 are the self-inductance values ​​of the first and third resonant inductors respectively, ω is the system angular frequency, C S is the coupling capacitor, where: C S =C2, C2 is the capacitance value of the second resonant capacitor.

9. The anti-drift wireless charging system for UAVs based on a concentric embracing coupling mechanism according to claim 6, characterized in that: When the transmitter and receiver are far apart, the total input impedance of the system is Z in2 for: Where L1 and L2 are the self-inductance values ​​of the first and second resonant inductors respectively, C1 is the capacitance value of the first resonant capacitor, and ω is the system angular frequency. According to the resonant condition of the resonant compensation circuit, it can be known that: ω 2 C1L2=1,Z in2 tends to infinity.

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