An autonomous wireless charging device for drones

Abstract

This invention relates to an autonomous wireless charging device for unmanned aerial vehicles (UAVs), comprising: a primary-side circuit mounted on a wireless charging platform and a secondary-side circuit mounted on the UAV; the primary-side circuit includes: a controller, an inverter circuit, a transmitter compensation structure, and a transmitter coil; the secondary-side circuit includes: a receiver coil and a rectifier circuit; the inverter circuit includes multiple power switches to convert DC power from a DC power supply into AC power; after the AC power is compensated by the transmitter compensation structure, the transmitter coil wirelessly transmits electrical energy to the receiver coil via magnetic induction; after the UAV's receiver coil is soft-started, the controller controls the resonant frequency of the transmitter and receiver coils to be the same as the switching frequency of the inverter; by using the controller to track changes in the resonant frequency, the switching frequency is made consistent with the resonant frequency, preventing the coupling coefficient of the primary-side transmitter coil and the secondary-side receiver coil from changing with their relative positions, thus preventing the system from losing resonance and achieving high-efficiency, high-power output in the wireless charging system.

Description

Technical Field

[0001] This invention relates to the field of drone charging, and more particularly to an autonomous wireless charging device for drones. Background Technology

[0002] Drone swarms face significant energy replenishment challenges when performing long-duration or long-distance missions. Traditional wired charging methods are efficient, stable, and compatible, but they require manual plugging and unplugging, and multi-drone charging necessitates complex cable management, making them unsuitable for large-scale drone operations. Solar charging converts solar energy into electricity to charge drone batteries, offering a green and sustainable solution. However, the conversion efficiency of solar power systems is severely affected by natural environmental factors such as sunlight intensity and weather conditions, resulting in the inability to recharge on cloudy days or at night. Furthermore, solar energy density is relatively low, requiring large solar panel areas for charging, and drones have limited payload capacity, making it difficult for solar energy to meet their high power demands.

[0003] While wireless charging is slightly less efficient than wired charging, its high degree of automation reduces a significant number of exposed cables and interfaces, and its good environmental adaptability provides a more reliable and efficient energy replenishment solution for drone swarms, making it key to solving the energy replenishment problem for drone swarms. However, existing wireless charging systems for drones still have some problems, including the inability to achieve full automation, narrow wireless charging range that is incompatible with multiple drone types, and high requirements for drone take-off and landing accuracy. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing an autonomous wireless charging device for unmanned aerial vehicles (UAVs). It adopts the principle of magnetic resonance and uses a controller to track changes in the resonant frequency, ensuring that the switching frequency matches the resonant frequency. This prevents the coupling coefficient between the primary transmitting coil and the secondary receiving coil from losing resonance due to changes in their relative positions, thereby achieving high-efficiency, high-power output in the wireless charging system.

[0005] According to a first aspect of the present invention, an autonomous wireless charging device for unmanned aerial vehicles (UAVs) is provided, comprising: a DC power supply and at least one magnetically coupled resonant energy transfer system; the magnetically coupled resonant energy transfer system is connected to the power supply; the magnetically coupled resonant energy transfer system includes a primary side circuit mounted on a wireless charging platform and a secondary side circuit mounted on the UAV.

[0006] The primary-side circuit includes: a controller, an inverter circuit, a transmitter compensation structure, and a transmitter coil; the secondary-side circuit includes: a receiver coil and a rectifier circuit.

[0007] The inverter circuit includes multiple power switches to convert DC power from a DC power supply into AC power. After the AC power is compensated by the transmitting end compensation structure, the transmitting coil wirelessly transmits electrical energy to the receiving coil via magnetic induction. The rectifier circuit rectifies the high-frequency AC power received by the receiving coil into DC power to supply the UAV. After the receiving coil of the UAV is soft-started, the controller controls the resonant frequency of the transmitting coil and the receiving coil to be the same as the switching frequency of the inverter.

[0008] Based on the above technical solution, the present invention can also be improved as follows.

[0009] Optionally, the inverter circuit consists of an input voltage regulator capacitor C. in A full-bridge inverter circuit consisting of a first power switch S1, a second power switch S2, a third power switch S3, and a fourth power switch S4;

[0010] The drive signals of the first power switch S1 and the second power switch S2 are opposite and they are closed alternately.

[0011] The drive signals of the fourth power switch S4 and the first power switch S1 are synchronized.

[0012] The drive signals of the third power switch S3 and the second power switch S2 are synchronized.

[0013] Optionally, the transmitter compensation structure includes: a primary-side compensation capacitor C. p ;

[0014] The primary-side compensation capacitor C p One end is connected to one output port of the inverter circuit, and the other end is connected to one end of the transmitting coil;

[0015] Optionally, the wireless charging device further includes: an auxiliary sampling circuit;

[0016] The auxiliary sampling circuit includes: an auxiliary resistor R aw Auxiliary transformer T aw Sampling capacitor C smp Sampling resistor R smp And an auxiliary rectifier circuit, which consists of a first auxiliary rectifier diode D5, a second auxiliary rectifier diode D6, a third auxiliary rectifier diode D7, and a fourth auxiliary rectifier diode D8;

[0017] The auxiliary resistor R aw One end is connected to the other output port of the inverter circuit, and the other end is connected to the other end of the transmitting coil;

[0018] The auxiliary transformer T awOne side winding and the auxiliary resistor R aw The two windings are connected in parallel. One end of the winding on the other side is connected to the positive terminal of the third auxiliary rectifier diode D7 and the negative terminal of the fourth auxiliary rectifier diode D8, and the other end of the winding on the other side is connected to the positive terminal of the third auxiliary rectifier diode D5 and the negative terminal of the fourth auxiliary rectifier diode D6.

[0019] The sampling capacitor C smp and sampling resistor R smp After being connected in parallel, one end is connected to the negative terminal of the third auxiliary rectifier diode D7, and the other end is connected to the positive terminal of the fourth auxiliary rectifier diode D6.

[0020] Optionally, after the soft start is completed, when the controller determines that the drive signal of the switching transistor of the inverter circuit triggers a falling edge, it collects the data entering the primary-side compensation capacitor C. p primary side current i p and the sampling resistor R smp auxiliary winding voltage at both ends V smp ;

[0021] if i p / V smp If >0, the controller controls the reduction of the inverter's switching frequency; if i p / V smp <0, the controller controls to increase the switching frequency of the inverter.

[0022] Optionally, the secondary-side circuit further includes: a receiving-end compensation structure; the receiving-end compensation structure includes a secondary-side compensation capacitor C connected in series with one end of the receiving coil. s .

[0023] Optionally, the rectifier circuit includes: a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, a fourth rectifier diode D4, and an output voltage regulating capacitor C. o ;

[0024] One end of the receiving coil is connected to the positive terminal of the first rectifier diode D1 and the negative terminal of the second rectifier diode D2, and the other end of the receiving coil is connected to the positive terminal of the third rectifier diode D3 and the negative terminal of the fourth rectifier diode D4.

[0025] The output voltage regulator capacitor C o One end is connected to the negative terminal of the third rectifier diode D3, and the other end is connected to the positive terminal of the fourth rectifier diode D4.

[0026] Optionally, the transmitting coil includes a primary-side transmitting inductor L. p The receiving coil includes a secondary receiving inductor L. s .

[0027] Optionally, the transmitter compensation structure further includes a primary-side equivalent line impedance R connected in series. p The receiving end compensation structure also includes a secondary-side equivalent line impedance R connected in series. s .

[0028] Optionally, the wireless charging platform includes: two layers of copper busbars and a primary side circuit located between the two layers of copper busbars;

[0029] Both copper busbars are hollow and have copper sheets on all four sides in a grid shape. The two copper busbars serve as the positive and negative input terminals of the primary side circuit, respectively. Each primary side circuit is set in its respective grid.

[0030] This invention provides an autonomous wireless charging device for unmanned aerial vehicles (UAVs). It employs a full-bridge inverter circuit to improve power density and efficiency. Both the transmitter and receiver compensation structures utilize series compensation circuits to reduce leakage inductance. Considering the limited internal size of UAVs, algorithm complexity, and reliability, a bridge uncontrolled rectifier circuit is used. A frequency tracking algorithm is provided, sampling the primary-side current of the primary-side compensation capacitor and the auxiliary winding voltage across the sampling resistor at the falling edge of the switching transistor drive signal, simplifying the control process. Utilizing a magnetic resonance principle, it can meet the demands of long-distance, high-power applications. It enables long-distance, high-capacity power transmission and rapid load adjustment and control. Compared to magnetic induction wireless charging systems, magnetic resonance wireless charging systems maintain better transmission performance over long and variable distances. It can autonomously wirelessly charge multiple UAVs with good anti-offset performance, achieving efficient charging within a certain range. Its simple structure allows for simultaneous wireless charging of multiple UAVs and tracking UAV offset to ensure wireless transmission efficiency. It is compatible with different UAV models, making it of significant practical importance for ensuring the swarm combat capability of UAVs. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of an embodiment of an autonomous wireless charging device for unmanned aerial vehicles provided by the present invention;

[0032] Figure 2 A circuit diagram of an embodiment of a magnetically coupled resonant energy transfer system for an autonomous wireless charging device for unmanned aerial vehicles provided by the present invention;

[0033] Figure 3 A schematic diagram of an embodiment of the present invention where the system switching frequency is greater than the system resonant frequency;

[0034] Figure 4 A schematic diagram of an embodiment of the present invention where the system switching frequency is less than the system resonant frequency;

[0035] Figure 5 This invention provides an overall control flowchart of the controller during the charging process of an autonomous wireless charging device for unmanned aerial vehicles;

[0036] Figure 6 This is a structural diagram of a wireless charging platform provided in an embodiment of the present invention;

[0037] Figure 7 A circuit diagram of another embodiment of the magnetically coupled resonant energy transfer system for an autonomous wireless charging device for unmanned aerial vehicles provided by the present invention;

[0038] Figure 8 The waveform diagram for when the transmitting coil and receiving coil are 0.9m apart, as provided in an embodiment of the present invention;

[0039] Figure 9 The waveform diagram is shown in the embodiment of the present invention when the transmitting coil and the receiving coil are 0.4m apart. Detailed Implementation

[0040] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0041] Figure 1 This is a schematic diagram of the structure of an autonomous wireless charging device for unmanned aerial vehicles provided by the present invention. Figure 2 A circuit schematic diagram of an embodiment of a magnetically coupled resonant energy transfer system for an autonomous wireless charging device for unmanned aerial vehicles provided by the present invention is shown below. Figure 1 and Figure 2 As shown, the wireless charging device includes: a DC power supply and at least one magnetically coupled resonant energy transfer system; the magnetically coupled resonant energy transfer system is connected to the power supply; the magnetically coupled resonant energy transfer system includes a primary side circuit mounted on the wireless charging platform and a secondary side circuit mounted on the drone.

[0042] The primary-side circuit includes: a controller, an inverter circuit, a transmitter compensation structure, and a transmitter coil; the secondary-side circuit includes: a receiver coil and a rectifier circuit.

[0043] The inverter circuit includes multiple power switches that convert DC power from the DC power supply into AC power. After the AC power is compensated by the transmitter compensation structure, the transmitter coil transmits electrical energy wirelessly to the receiver coil through magnetic induction. The rectifier circuit rectifies the high-frequency AC power received by the receiver coil into DC power to supply the drone. After the drone's receiver coil is soft-started, the controller controls the resonant frequency of the transmitter coil and the receiver coil to be the same as the switching frequency of the inverter.

[0044] The present invention provides an autonomous wireless charging device for unmanned aerial vehicles (UAVs) that adopts the principle of magnetic resonance. The controller tracks the change of the resonant frequency to make the switching frequency consistent with the resonant frequency, preventing the coupling coefficient of the primary transmitting coil and the secondary receiving coil from losing resonance due to the change of their relative positions, thereby achieving high-efficiency and high-power output in the wireless charging system.

[0045] Example 1

[0046] Embodiment 1 provided by this invention is an embodiment of an autonomous wireless charging device for unmanned aerial vehicles provided by this invention, combined with... Figure 1 and Figure 2 It is understood that the embodiment of the wireless charging device includes: a DC power supply and at least one magnetically coupled resonant energy transfer system; the magnetically coupled resonant energy transfer system is connected to the power supply; the magnetically coupled resonant energy transfer system includes a primary side circuit installed on the wireless charging platform and a secondary side circuit installed on the drone.

[0047] Based on practical needs, DC power can be supplied by devices such as batteries or generators, and then output as a stable DC voltage. Taking battery power as an example, the battery outputs stable DC power to the wireless charging platform after conversion by a DC-DC converter. The wireless charging platform contains n energy transmitting devices and n transmitting coils, which can charge up to n drones simultaneously. The energy transmitting devices convert the DC power input from the DC power supply into high-frequency AC power, allowing the transmitting coils to emit energy. The drone's receiving coil receives the energy transmitted from the transmitting side through magnetic induction, and uses a high-frequency rectifier circuit to rectify the received high-frequency AC power into DC power, which is then further modulated by the DC-DC converter to charge the drone's battery.

[0048] The primary-side circuit includes: a controller, an inverter circuit, a transmitter compensation structure, and a transmitter coil; the secondary-side circuit includes: a receiver coil and a rectifier circuit.

[0049] The inverter circuit includes multiple power switches that convert DC power from the DC power supply into AC power. After the AC power is compensated by the transmitter compensation structure, the transmitter coil transmits electrical energy wirelessly to the receiver coil through magnetic induction. The rectifier circuit rectifies the high-frequency AC power received by the receiver coil into DC power to supply the drone. After the drone's receiver coil is soft-started, the controller controls the resonant frequency of the transmitter coil and the receiver coil to be the same as the switching frequency of the inverter.

[0050] In one possible embodiment, the inverter circuit is composed of an input voltage regulator capacitor C. in A full-bridge inverter circuit consisting of a first power switch S1, a second power switch S2, a third power switch S3, and a fourth power switch S4.

[0051] Input voltage regulator capacitor C in After connecting both ends to the DC power supply, one end is connected to the drain of the first power switch S1 and the third power switch S3, and the other end is connected to the source of the second power switch S2 and the fourth power switch S4. The connection between the source of the first power switch S1 and the drain of the second power switch S2 serves as one output port of the inverter circuit, and the connection between the source of the third power switch S3 and the drain of the fourth power switch S4 serves as the other output port of the inverter circuit.

[0052] The drive signals of the first power switch S1 and the second power switch S2 are opposite and they are closed alternately.

[0053] The drive signals of the fourth power switch S4 and the first power switch S1 are synchronized.

[0054] The drive signals of the third power switch S3 and the second power switch S2 are synchronized.

[0055] In practice, a diode is connected between the drain and source of each power switch. Compared with the traditional half-bridge inverter circuit, the current withstand capability requirement of the switching transistors in the full-bridge inverter circuit is reduced by 50% for the same power. Therefore, although the full-bridge inverter circuit requires more switching transistors, the converter using the full-bridge inverter circuit still has significant advantages in terms of power density and efficiency, and is therefore often used in high-power applications.

[0056] Because the transmitting and receiving coils are inductive at high switching frequencies with significant leakage inductance, the magnetic field generated by the transmitter cannot be fully picked up by the receiver, resulting in high reactive power content in the wireless charging system. This not only increases device capacity but also reduces system efficiency. Therefore, a resonant compensation system is needed to compensate the transmitter and receiver. The output power of a series-series (SS) compensation network is linearly related to the load, and the primary-side compensation capacitor is only related to the resonant angular frequency and the inductance of the transmitting coil under resonant conditions. Therefore, both the transmitter and receiver compensation structures use series compensation circuits.

[0057] In one possible embodiment, the transmitter compensation structure includes: a primary-side compensation capacitor C. p .

[0058] Primary-side compensation capacitor C p One end is connected to one output port of the inverter circuit, and the other end is connected to one end of the transmitting coil.

[0059] In one possible embodiment, the wireless charging device further includes an auxiliary sampling circuit.

[0060] The auxiliary sampling circuit includes: auxiliary resistor R aw Auxiliary transformer T aw Sampling capacitor C smp Sampling resistor R smp And an auxiliary rectifier circuit, which consists of a first auxiliary rectifier diode D5, a second auxiliary rectifier diode D6, a third auxiliary rectifier diode D7, and a fourth auxiliary rectifier diode D8.

[0061] Auxiliary resistor R aw One end is connected to the other output port of the inverter circuit, and the other end is connected to the other end of the transmitting coil.

[0062] Auxiliary transformer T aw One side winding and auxiliary resistor R aw The two windings are connected in parallel. One end of the winding on the other side is connected to the positive terminal of the third auxiliary rectifier diode D7 and the negative terminal of the fourth auxiliary rectifier diode D8, and the other end of the winding on the other side is connected to the positive terminal of the third auxiliary rectifier diode D5 and the negative terminal of the fourth auxiliary rectifier diode D6.

[0063] Sampling capacitor C smp and sampling resistor R smp After being connected in parallel, one end is connected to the negative terminal of the third auxiliary rectifier diode D7, and the other end is connected to the positive terminal of the fourth auxiliary rectifier diode D6.

[0064] In this magnetically coupled resonant energy transfer system, the primary-side transmitting coil L pand secondary receiving coil L s The coupling coefficient changes with the relative position of the two, causing the system to lose resonance. Therefore, the corresponding resonant frequency in the resonant circuit will change. The controller needs to track the change of resonant frequency to make the switching frequency consistent with the resonant frequency in order to achieve high-efficiency and high-power output. Therefore, a frequency tracking algorithm needs to be developed.

[0065] The frequency tracking algorithm in this invention requires sampling at the falling edge of the switching transistor drive signal. i p and V smp The following example will be based on the drive signal G1 of the first switching transistor S1. Figure 3 The diagram shown is a schematic representation of an embodiment of the present invention where the system switching frequency is greater than the system resonant frequency. Figure 4 The diagram shown is a schematic representation of an embodiment of the present invention where the system switching frequency is lower than the system resonant frequency. Figure 3 and Figure 4 In the diagram, the red line represents the S1 drive signal G1, and the blue line represents the primary current. i p .

[0066] like Figure 3 As shown, when the system switching frequency is greater than the system resonant frequency, the resonant circuit is inductive, and the current lags behind the voltage. At the falling edge of G1, i p Greater than 0; such as Figure 4 As shown, when the system switching frequency is less than the system resonant frequency, the resonant circuit is capacitive, and the current leads the voltage. At the falling edge of G1, i p Less than 0; when the system switching frequency equals the system resonant frequency, the equivalent reactance on the primary side is 0, the voltage phase is consistent with the current phase, and at the falling edge of G1... i p Approximately equal to 0. Therefore, with i p Controlling the system's switching frequency with a control signal can gradually bring it closer to the resonant frequency. However, when the system switching frequency fs is far from the resonant frequency fr, the system's transmitted power is extremely low. i p A small absolute value results in a slow approach to the resonant frequency by the system switching frequency; when the system switching frequency fs approaches the resonant frequency fr, the system transmission power increases sharply. i p Large absolute value fluctuations cause the switching frequency to fluctuate significantly around the resonant frequency, resulting in substantial current surges. Therefore, considering... V smp It can indicate the average value of the primary side current, in order to i p / V smpBy controlling the quantity, the above problems can be effectively improved.

[0067] like Figure 5 The diagram shown is an overall control flowchart of the controller during the charging process of the autonomous wireless charging device for unmanned aerial vehicles provided by the present invention. Figure 5 It can be seen that after the drone establishes communication with the wireless charging device, the wireless charging device instructs the drone to move to the charging coil x (x=1,2…n). Once the drone is in position, charging begins. After charging begins, the wireless charging device first performs a soft start, pushing the frequency up to the maximum switching frequency and maintaining this for a period of time. After the soft start ends, the primary side current is sampled whenever the drive signal G1 of the first switching transistor S1 triggers a falling edge. i p and auxiliary winding voltage V smp ,if i p / V smp If >0, then reduce the switching frequency; if i p / V smp If the value is less than 0, then increase the switching frequency. Finally... i p / V smp The output will be adjusted to fluctuate around 0, and the system will maintain high power output.

[0068] Figure 2 The red "×" indicates the primary current i. p Sampling point, V in V is the input voltage. o V is the output voltage. smp To assist the winding voltage. In one possible embodiment, after the soft start is complete, the controller, upon determining that the drive signal of the inverter circuit's switching transistor has triggered a falling edge, samples the voltage entering the primary-side compensation capacitor C. p primary side current i p and sampling resistor R smp auxiliary winding voltage at both ends V smp .

[0069] if i p / V smp If >0, the controller reduces the inverter's switching frequency; if i p / V smp <0, the controller increases the switching frequency of the inverter.

[0070] In one possible embodiment, the secondary-side circuit further includes: a receiver compensation structure; the receiver compensation structure includes a secondary-side compensation capacitor C connected in series with one end of the receiving coil. s .

[0071] In one possible embodiment, the rectifier circuit includes: a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, a fourth rectifier diode D4, and an output voltage regulator capacitor C. o .

[0072] One end of the receiving coil is connected to the positive terminal of the first rectifier diode D1 and the negative terminal of the second rectifier diode D2, and the other end of the receiving coil is connected to the positive terminal of the third rectifier diode D3 and the negative terminal of the fourth rectifier diode D4.

[0073] Output voltage regulator capacitor C o One end is connected to the negative terminal of the third rectifier diode D3, and the other end is connected to the positive terminal of the fourth rectifier diode D4.

[0074] In practice, to charge the battery, the high-frequency AC power from the receiving end needs to be rectified and filtered into stable DC power. Common rectification methods include controlled rectification and uncontrolled rectification. Considering the limited internal size of the drone, algorithm complexity, and reliability issues, a bridge-type uncontrolled rectifier circuit is used in the rectification circuit.

[0075] In one possible embodiment, the transmitting coil includes a primary-side transmitting inductor L. p The receiving coil includes a secondary receiving inductor L. s .

[0076] In one possible embodiment, the transmitter compensation structure further includes a primary-side equivalent line impedance R connected in series. p The receiver compensation structure also includes the series-connected secondary-side equivalent line impedance R. s .

[0077] The system of this invention consists of a DC power supply and a wireless charging platform. In one possible embodiment, the wireless charging platform includes two layers of copper busbars and a primary-side circuit located between the two layers of copper busbars.

[0078] Both copper busbars are hollow and have copper sheets on all four sides in a grid shape. The two copper busbars serve as the positive and negative input terminals of the primary side circuits, respectively. Each primary side circuit is set in its respective grid.

[0079] like Figure 6 The diagram shown is a structural diagram of a wireless charging platform provided in an embodiment of the present invention. Figure 6As can be seen, the maximum number of devices, n, that can be charged in the wireless charging platform of this invention can be freely set, and the architecture is flexible. The following description uses n=9 as an example. As shown in Figure b, the wireless charging platform has a platform-like appearance and is divided into a 3×3 grid by copper busbars, which can charge 9 drones simultaneously. In the figure, the blue mesh structure is the copper busbar connected to the negative terminal of the DC power supply, the red mesh structure is the copper busbar connected to the positive terminal of the DC power supply, the green structure is 9 energy transmitting devices, including an inverter circuit, a transmitter compensation structure and a controller, the purple structure is 9 square transmitting coils, evenly distributed in the 9 grids, and the gray structure is 7 support columns, which help support the overall structure.

[0080] Example 2

[0081] Embodiment 2 provided by this invention is a specific application embodiment of the autonomous wireless charging device for unmanned aerial vehicles provided by this invention, such as... Figure 7 The diagram shown is a circuit schematic of another embodiment of the magnetically coupled resonant energy transfer system for an autonomous wireless charging device for unmanned aerial vehicles provided by the present invention. The parameters in this embodiment are: input voltage V... in =500V; Input voltage regulator capacitor C in =100µF; Compensation capacitor C p =C s =1nF; Self-inductance of transmitting and receiving coils L p =L s =300µH; Equivalent line impedance of primary and secondary sides R p =R s =2Ω; Output voltage regulator capacitor C o =50µF; Load resistance R o =200Ω; Switches S1, S2, S3, and S4 are all SiC MOSFETs; Rectifier diodes D1, D2, D3, and D4 are all SiC diodes; Auxiliary rectifier diodes D5, D6, D7, and D8 are all fast recovery diodes; Auxiliary sampling resistor R aw =0.3Ω, turns ratio 3:2; auxiliary sampling capacitor C smp =10µF; Auxiliary sampling resistor R smp =60Ω; Maximum switching frequency f max =400kHz; Maximum switching frequency f max =150kHz; soft start time is 0.05s.

[0082] like Figure 8 The figure shown is a waveform diagram of the operation when the transmitting coil and receiving coil are 0.9m apart, according to an embodiment of the present invention. Figure 8In the middle, red represents the output voltage Vo, blue represents the output current of the rectifier circuit, and green represents the switching frequency. During the 0-0.05s period, the system is in a soft-start state, and the switching frequency is maintained at the maximum switching frequency of 400kHz. Subsequently, the controller begins to adjust the switching frequency and eventually stabilizes at around 291.7kHz. At this time, the output voltage is approximately 1090V and the output power is approximately 12kW.

[0083] like Figure 9 The figure shown is a waveform diagram of the operation when the transmitting coil and receiving coil are 0.4m apart, according to an embodiment of the present invention. Figure 9 In the middle, red represents the output voltage Vo, blue represents the output current of the rectifier circuit, and green represents the switching frequency. During the 0-0.05s period, the system is in a soft-start state, and the switching frequency is maintained at the maximum switching frequency of 400kHz. Subsequently, the controller begins to adjust the switching frequency and eventually stabilizes at around 329.1kHz. At this time, the output voltage is approximately 472.4V and the output power is approximately 2.2kW.

[0084] This invention provides an autonomous wireless charging device for unmanned aerial vehicles (UAVs). It employs a full-bridge inverter circuit to improve power density and efficiency. Both the transmitting and receiving compensation structures use series compensation circuits to reduce leakage inductance. Considering the limited internal size of the UAV, algorithm complexity, and reliability issues, a bridge uncontrolled rectifier circuit is used. A frequency tracking algorithm is provided, sampling the primary-side current of the primary-side compensation capacitor and the auxiliary winding voltage across the sampling resistor at the falling edge of the switching transistor drive signal, simplifying the control process. Utilizing the magnetic resonance principle, it can meet the demands of long-distance, high-power applications. It enables long-distance, high-capacity power transmission and rapid load adjustment and control. Compared to magnetic induction wireless charging systems, magnetic resonance wireless charging systems maintain better transmission performance over long and variable distances. It can autonomously wirelessly charge multiple UAVs with good anti-offset performance, achieving efficient charging within a certain range. Its simple structure allows for simultaneous wireless charging of multiple UAVs and tracking UAV offset to ensure wireless transmission efficiency. It is compatible with different UAV models and has significant practical implications for ensuring the swarm combat capability of UAVs.

[0085] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0086] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0087] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0088] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0089] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0090] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0091] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An autonomous wireless charging device for unmanned aerial vehicles (UAVs), characterized in that, The wireless charging device includes: a DC power supply and at least one magnetically coupled resonant energy transmission system; the magnetically coupled resonant energy transmission system is connected to the power supply; the magnetically coupled resonant energy transmission system includes: a primary side circuit installed on the wireless charging platform and a secondary side circuit installed on the drone. The primary-side circuit includes: a controller, an inverter circuit, a transmitter compensation structure, and a transmitter coil; the secondary-side circuit includes: a receiver coil and a rectifier circuit. The inverter circuit includes multiple power switches to convert the DC power supply into AC power. After the transmitting end compensation structure compensates for the AC power, the transmitting coil wirelessly transmits the AC power to the receiving coil through magnetic induction. The rectifier circuit rectifies the high-frequency AC power received by the receiving coil into DC power to supply the UAV. After the receiving coil of the UAV is soft-started, the controller controls the resonant frequency of the transmitting coil and the receiving coil to be the same as the switching frequency of the inverter circuit. The transmitter compensation structure includes: a primary-side compensation capacitor C. p ; The primary-side compensation capacitor C p One end is connected to one output port of the inverter circuit, and the other end is connected to one end of the transmitting coil; The wireless charging device further includes: an auxiliary sampling circuit; The auxiliary sampling circuit includes: an auxiliary resistor R aw Auxiliary transformer T aw Sampling capacitor C smp Sampling resistor R smp And an auxiliary rectifier circuit, which consists of a first auxiliary rectifier diode D5, a second auxiliary rectifier diode D6, a third auxiliary rectifier diode D7, and a fourth auxiliary rectifier diode D8; The auxiliary resistor R aw One end is connected to the other output port of the inverter circuit, and the other end is connected to the other end of the transmitting coil; The auxiliary transformer T aw One side winding and the auxiliary resistor R aw The two windings are connected in parallel. One end of the winding on the other side is connected to the positive terminal of the third auxiliary rectifier diode D7 and the negative terminal of the fourth auxiliary rectifier diode D8, and the other end of the winding on the other side is connected to the positive terminal of the third auxiliary rectifier diode D5 and the negative terminal of the fourth auxiliary rectifier diode D6. The sampling capacitor C smp and sampling resistor R smp After being connected in parallel, one end is connected to the negative terminal of the third auxiliary rectifier diode D7, and the other end is connected to the positive terminal of the fourth auxiliary rectifier diode D6. After the soft start is completed, the controller, upon determining that the drive signal of the inverter circuit's switching transistor has triggered a falling edge, acquires the data entering the primary-side compensation capacitor C. p primary side current i p and the sampling resistor R smp auxiliary winding voltage at both ends V smp ; if i p / V smp If >0, the controller controls the reduction of the switching frequency of the inverter circuit; if i p / V smp <0, the controller controls to increase the switching frequency of the inverter circuit.

2. The wireless charging device according to claim 1, characterized in that, The inverter circuit consists of an input voltage regulator capacitor C. in A full-bridge inverter circuit consisting of a first power switch S1, a second power switch S2, a third power switch S3, and a fourth power switch S4; The drive signals of the first power switch S1 and the second power switch S2 are opposite and they are closed alternately. The drive signals of the fourth power switch S4 and the first power switch S1 are synchronized. The drive signals of the third power switch S3 and the second power switch S2 are synchronized.

3. The wireless charging device according to claim 1, characterized in that, The secondary-side circuit further includes: a receiving-end compensation structure; the receiving-end compensation structure includes a secondary-side compensation capacitor C connected in series with one end of the receiving coil. s .

4. The wireless charging device according to claim 1, characterized in that, The rectifier circuit includes: a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, a fourth rectifier diode D4, and an output voltage regulator capacitor C. o ; One end of the receiving coil is connected to the positive terminal of the first rectifier diode D1 and the negative terminal of the second rectifier diode D2, and the other end of the receiving coil is connected to the positive terminal of the third rectifier diode D3 and the negative terminal of the fourth rectifier diode D4. The output voltage regulator capacitor C o One end is connected to the negative terminal of the third rectifier diode D3, and the other end is connected to the positive terminal of the fourth rectifier diode D4.

5. The wireless charging device according to claim 1, characterized in that, The transmitting coil includes a primary-side transmitting inductor L. p The receiving coil includes a secondary receiving inductor L. s .

6. The wireless charging device according to claim 3, characterized in that, The transmitter compensation structure also includes the primary-side equivalent line impedance R connected in series. p The receiving end compensation structure also includes a secondary-side equivalent line impedance R connected in series. s .

7. The wireless charging device according to claim 1, characterized in that, The wireless charging platform includes: two layers of copper busbars and a primary side circuit located between the two layers of copper busbars. Both copper busbars are hollow and have copper sheets on all four sides in a grid shape. The two copper busbars serve as the positive and negative input terminals of the primary side circuit, respectively. Each primary side circuit is set in its respective grid.

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