An adaptive omnidirectional anti-displacement wireless charging system and charging method for unmanned aerial vehicles

Abstract

This invention discloses an adaptive omnidirectional anti-offset wireless charging system and method for unmanned aerial vehicles (UAVs). The system includes a charging platform and a UAV. The charging platform is mutually coupled to the receiving coil resonant network via its transmitting coil resonant network and its judging coil resonant network, respectively. This enables the wireless charging platform to transmit electrical energy to the UAV. The electrical energy output from the receiving coil resonant network is rectified and then flows into the battery charging circuit to charge the UAV. The UAV determines its required charging state based on monitoring data and transmits this state information to the charging platform. The charging platform then switches the charging state according to the state information, completing the omnidirectional anti-offset wireless charging operation of the UAV wireless charging system. This invention achieves optimization and improvement in multiple aspects of the wireless charging system, including high transmission efficiency, high anti-offset characteristics, and omnidirectional anti-offset capability, demonstrating excellent practicality and application prospects in the field of wireless charging.

Description

Technical Field

[0001] This invention relates to wireless power transmission technology, and more specifically to an adaptive omnidirectional anti-offset wireless charging system and charging method for unmanned aerial vehicles. Background Technology

[0002] In the rapid development of drone technology, flight time has always been a key issue limiting its application. Drones typically rely on lithium batteries for power, which limits their flight time. To extend mission duration, drones must periodically return to charging stations for battery replacement or recharging, which increases mission complexity and cost.

[0003] To address the issue of drone flight endurance, there are generally three solutions: First, from the perspective of energy supply, research high-capacity battery technology, using high-capacity lithium batteries or other advanced battery technologies to increase battery energy density and thus extend flight time; second, from the perspective of energy consumption, optimize the design and construction of drones to reduce power consumption and improve battery efficiency to lower energy consumption; and third, from the perspective of energy replenishment, research automated wireless charging technology to charge the device without physical direct contact, eliminating the need for human intervention and improving the overall flight endurance of drones through fully automated charging.

[0004] Existing wireless charging technology suffers from a misalignment problem: when the transmitting and receiving coils of a wireless power transmission system are misaligned, it can cause severe fluctuations in output power and even prevent the system from transmitting power normally. Existing anti-misalignment features are mostly achieved through relatively complex coil structures and circuit topologies. However, such complex circuit designs increase system losses, and the complex coil structures also increase copper losses, which further reduces the system's transmission efficiency. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide an adaptive omnidirectional anti-offset wireless charging system for drones. By improving the coil structure and adding an adaptive switching control strategy, it is possible to simultaneously improve both high anti-offset capability and high transmission efficiency.

[0006] Technical Solution: This invention provides an adaptive omnidirectional anti-offset wireless charging system for unmanned aerial vehicles (UAVs), comprising a charging platform and a UAV. The charging platform includes a power module, a charging state switching circuit, a transmitting coil resonant network, and a judgment coil resonant network. The charging state switching circuit includes a first MCU control circuit, a first switching circuit, a second switching circuit, and a third switching circuit. The transmitting coil resonant network includes a transmitting coil and a transmitting compensation topology, and the judgment coil resonant network includes a judgment coil and a judgment compensation topology. The UAV includes a receiving coil resonant network, a rectifier circuit, a battery charging circuit, and a charging monitoring circuit. The receiving coil resonant network includes a receiving coil and a receiving compensation topology. The power module provides power to the entire system. Electrical energy is transmitted from the transmitting coil and the judgment coil to the receiving coil via mutual inductive coupling. This enables the wireless charging platform to transmit electrical energy to the drone. The electrical energy output from the receiving coil resonant network flows into the battery charging circuit after being rectified by the rectifier circuit to charge the drone. The charging monitoring circuit monitors the output of the receiving coil resonant network and determines the required charging state of the drone based on the monitoring data. Simultaneously, it transmits the status information to the first MCU control circuit. The first MCU control circuit controls the working state of the first switching circuit, the second switching circuit, and the third switching circuit based on the status information, thereby controlling the coupling state between the transmitting coil and the judgment coil and the receiving coil, realizing the switching of the charging state, and completing the omnidirectional anti-offset wireless charging operation of the drone wireless charging system.

[0007] The charging state switching circuit includes three charging states:

[0008] In state I, the first switching circuit is in operation, while the second and third switching circuits are not in operation. The transmitting coil is forward conducting, the judgment coil is not conducting, and the transmitting coil transmits electrical energy to the receiving coil.

[0009] In state II, the second switching circuit is in operation, the first and third switching circuits are not in operation, the transmitting coil is reverse-conducting, the judgment coil is not conducting, and the transmitting coil transmits electrical energy to the receiving coil.

[0010] In state III, the third switching circuit is in operation, the first and second switching circuits are not in operation, the transmitting coil is not conducting, the judgment coil is forward conducting, and the judgment coil transmits electrical energy to the receiving coil.

[0011] The relationship between monitoring data and charging status is as follows:

[0012] The charging monitoring circuit obtains the charging efficiency η based on the monitoring data;

[0013] η>η A At that time, η A Given the first preset charging efficiency threshold, the required charging state for the drone is: State I;

[0014] η B <η<η A At that time, η B The second preset charging efficiency threshold requires the drone to be charged in State III.

[0015] η C <η<η B At that time, η C The third preset charging efficiency threshold requires the drone to be charged in State II.

[0016] η<η C At that time, the drone needs to be charged in the following state: State I.

[0017] Optionally, the power module includes a DC power supply, a high-frequency full-bridge inverter circuit, and a drive circuit. The drive circuit generates a PWM signal and converts it into a MOSFET drive signal to drive the high-frequency full-bridge inverter circuit to invert the DC power input from the DC power supply into AC power of a specified frequency, thereby providing power to the system.

[0018] Optionally, the transmitting coil includes an upper coil and a lower coil, which are wound in opposite directions and connected in series. The lower coil is centered on a fifth square coil, with the second, eighth, fourth, and sixth square coils connected in series in the four directions of up, down, left, and right respectively. The completed coil is cut along the upper left, lower left, and lower right vertices of the central fifth square coil at a 45° angle and the upper right vertices at a 135° angle, forming a single loop. The upper coil is centered on a tenth square coil that surrounds the central fifth square coil, with the first, seventh, third, and ninth square coils connected in series in the four directions of up, down, left, up, and right respectively. The completed coil is cut along the upper left and lower right vertices of the central tenth square coil at a 45° angle and the lower left and upper right vertices at a 135° angle, forming a single loop. The two coils together form a hollow nine-square grid shape, with the current flowing through adjacent squares in opposite directions.

[0019] Optionally, the first end of the transmitting coil and the first end of the receiving coil are of the same name. The formula for calculating the mutual inductance coefficient of each square coil in the transmitting coil and the receiving coil is as follows:

[0020]

[0021] in, Let μj be the mutual inductance between the j-th side of the i-th square coil in the transmitting coil and the receiving coil, μ0 be the free permeability, and aj be the mutual inductance. i Let be the side length of the i-th square coil in the transmitting coil, r be the radius of the receiving coil, and t be the side length of the square coil in the transmitting coil. i Let the center of the i-th square coil in the transmitting coil be along the y-axis with the center of the receiving coil.i The distance of shaft offset, h i The distance θ along the z-axis between the center of the i-th square coil in the transmitting coil and the center of the receiving coil i The included angle M between the i-th square coil in the transmitting coil and the receiving coil TRi The mutual inductance M between the i-th square coil in the transmitting coil and the receiving coil Σ The mutual inductance value between the entire transmitting coil and the receiving coil

[0022] Optionally, the judgment coil includes an inner coil and an outer coil. The inner coil is composed of the eleventh square coil, the twelfth square coil, the thirteenth square coil, and the fourteenth square coil connected in series to form a "field" shape. Each square coil of the inner coil has the same size as each grid area in the nine-square grid area of the transmitting coil. It is cut along the 45° and 135° directions at the center position of the inner coil to form a single loop, and the current flowing through each grid of the inner coil has the same direction; the outer coil is a fifteenth square coil that surrounds the inner coil, and the current direction of the outer coil is the same as that of the inner coil, and the two sets of inner and outer coils are connected in series.

[0023] Optionally, the first end of the judgment coil and the first end of the receiving coil are of the same name. The calculation formula for the mutual inductance coefficient between each square coil in the judgment coil and the receiving coil is:

[0024] [[ID=Z18]]

[0025] Where is the mutual inductance value between the p-th side of the q-th square coil in the judgment coil and the receiving coil, μ0 is the vacuum permeability, a q is the side length of the q-th square coil in the judgment coil, r is the radius of the receiving coil, t q is the distance h along the y-axis between the center of the q-th square coil in the judgment coil and the center of the receiving coil q The distance of shaft offset, h q The distance θ along the z-axis between the center of the q-th square coil in the judgment coil and the center of the receiving coil q The included angle M between the q-th square coil in the judgment coil and the receiving coil JRq The mutual inductance M between the q-th square coil in the judgment coil and the receiving coil JΣ The mutual inductance value between the entire judgment coil and the receiving coil

[0026] Optionally, the receiving coil, the judgment coil, and the transmitting coil are stacked from top to bottom in sequence to form an overall structure, and a magnetic core is stacked below the transmitting coil; the receiving coil is a circular coil, and the magnetic core covers the entire area of the transmitting coil.

[0027] Optionally, the first switching circuit includes a first field-effect transistor S1 and a fourth field-effect transistor S4, the second switching circuit includes a second field-effect transistor S2 and a third field-effect transistor S3, and the third switching circuit includes a fifth field-effect transistor S5.

[0028] When the first field-effect transistor S1 and the fourth field-effect transistor S4 are turned on, and the second field-effect transistor S2, the third field-effect transistor S3, and the fifth field-effect transistor S5 are turned off, the first field-effect transistor S1 and the fourth field-effect transistor S4 form a circuit with the resonant network of the transmitting coil, the transmitting coil is forward-biased, and the judgment coil is not conductive, thus realizing the transmission of electrical energy from the transmitting coil to the receiving coil; when the second field-effect transistor S2 and the third field-effect transistor S3 are turned on, and the first field-effect transistor S1, the fourth field-effect transistor S4, and the fifth field-effect transistor S5 are turned off, the second field-effect transistor S2 and the third field-effect transistor S3 form a circuit with the resonant network of the transmitting coil, the transmitting coil is reverse-biased, and the judgment coil is not conductive, thus realizing the transmission of electrical energy from the transmitting coil to the receiving coil; when the first field-effect transistor S1, the second field-effect transistor S2, the third field-effect transistor S3, and the fourth field-effect transistor S4 are turned off, and the fifth field-effect transistor S5 is turned on, the fifth field-effect transistor S5 forms a circuit with the judgment coil, the transmitting coil is not conductive, the judgment coil is forward-biased, and the judgment coil transmits electrical energy to the receiving coil.

[0029] The charging state switching circuit also includes a first Bluetooth, which is used to receive status signals emitted by the drone. The first MCU control circuit analyzes and processes the received status signals and controls the conduction state of the first field-effect transistor S1, the second field-effect transistor S2, the third field-effect transistor S3, the fourth field-effect transistor S4, and the fifth field-effect transistor S5, thereby switching the charging platform to the specified charging state.

[0030] Optionally, the charging monitoring circuit includes a voltage monitoring circuit, a current monitoring circuit, a second MCU control circuit, and a second Bluetooth. The voltage monitoring circuit is connected in parallel with the battery charging circuit, and the current monitoring circuit is connected in series between the rectifier circuit and the battery charging circuit. The voltage monitoring circuit and the current monitoring circuit are used to monitor the charging voltage and charging current of the drone, respectively, and transmit them to the second MCU control circuit. The second MCU control circuit analyzes and processes the charging voltage and charging current of the drone to obtain the required charging status of the drone, and sends the status signal to the charging platform section through the second Bluetooth.

[0031] Based on the same inventive concept, the present invention provides an adaptive omnidirectional anti-displacement wireless charging method for unmanned aerial vehicles, comprising the following steps:

[0032] S1. Initialize the system. The drive circuit generates a MOSFET drive signal to drive the high-frequency full-bridge inverter circuit to convert the DC power input into AC power of a specified frequency, turn on the fifth field-effect transistor, and determine that the coil has entered the working state.

[0033] S2. The drone flies into the charging platform, where a detection coil pre-charges it. The second MCU control circuit of the drone determines the required charging state based on the charging efficiency and transmits the status data to the charging state switching circuit of the charging platform. Specifically:

[0034] The voltage monitoring circuit is used to monitor the charging voltage, and the current monitoring circuit is used to monitor the charging current. The charging voltage and charging current are then output to the second MCU control circuit.

[0035] The second MCU control circuit analyzes and processes the charging voltage and charging current, and calculates the output power P of the charger. out Combined with the preset input power P in The charging efficiency η can be calculated by the second MCU control circuit, and the required charging state can be determined. The method for determining the charging state is as follows:

[0036] (1) Judgment η>η A If the condition is true, output the character "State I", indicating that the required charging state is State I, and execute step (4); otherwise, execute step (2).

[0037] (2) Judgment η>η B If the condition is true, output the character "State III", indicating that the required charging state is State III, and execute step (4); otherwise, execute step (3).

[0038] (3) Judgment η>η C If the condition is true, output the character "State II", indicating that the required charging state is State II, and execute step (4); if not, output the character "State I", indicating that the required charging state is State I, and execute step (4).

[0039] (4) The second MCU control circuit transmits the status information corresponding to the output character to the first MCU control circuit of the charging platform section.

[0040] S3. After receiving the status information data, the first MCU control circuit of the charging platform controls the first field-effect transistor S1, the second field-effect transistor S2, the third field-effect transistor S3, the fourth field-effect transistor S4, and the fifth field-effect transistor S5 to perform corresponding actions to switch the charging state, completing the omnidirectional anti-offset operation of the drone wireless charging system; specifically:

[0041] When the status information is "Status I", the first MCU control circuit controls the first field-effect transistor S1 and the fourth field-effect transistor S4 to be turned on, and controls the second field-effect transistor S2, the third field-effect transistor S3 and the fifth field-effect transistor S5 to be turned off. At this time, the charging platform switches to charging status I.

[0042] When the status information is "Status II", the first MCU control circuit controls the second field-effect transistor S2 and the third field-effect transistor S3 to be turned on, and the first field-effect transistor S1, the fourth field-effect transistor S4 and the fifth field-effect transistor S5 to be turned off, and the transmitting coil is turned on in reverse, and the charging platform switches to charging status II.

[0043] When the status information is "Status III", the first MCU control circuit controls the fifth field-effect transistor S5 to be turned on, and the first field-effect transistor S1 to the fourth field-effect transistor S4 are turned off. The charging platform switches to charging status III. At this time, the charging platform charges the drone by judging the coil, and the transmitting coil is not turned on.

[0044] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0045] (1) The receiving coil, judging coil and transmitting coil are made of simple square coils wound and superimposed. The overall coil structure is simple and the copper loss is small. The circuit resonant network adopts a series topology resonant network, which has a small system loss. Furthermore, by selecting the stable section of the mutual inductance of the winding method with a large mutual inductance between the coils, the overall power transmission takes into account both high transmission efficiency and high anti-offset characteristics.

[0046] (2) The present invention adopts adaptive switching control. The control logic is based on the system electrical parameters. It consists of five field-effect transistors, MCU control circuit and Bluetooth to form a charging state switching circuit and establishes a communication connection with the device to be charged. It can monitor the charging state of the device to be charged and make corresponding switching, eliminate human interference, is stable and reliable, and responds quickly. It can effectively improve the anti-offset characteristics of the wireless charging system and maintain the transmission efficiency of the system at a high level.

[0047] (3) The wireless charging system of the present invention transfers energy between the power supply equipment and the power consumption equipment through an electromagnetic field, without the need for direct physical contact. It can effectively cope with the impact of severe weather and humid environment on drone charging, and the power supply reliability is high. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of an adaptive omnidirectional anti-offset wireless charging system for unmanned aerial vehicles provided in an embodiment of the present invention;

[0049] Figure 2 This is a coil structure diagram of an adaptive omnidirectional anti-offset wireless charging system for unmanned aerial vehicles provided in an embodiment of the present invention;

[0050] Figure 3 This is a diagram showing the change in mutual inductance caused by the change in the size of the transmitting coil, provided in an embodiment of the present invention.

[0051] Figure 4This is a circuit diagram of an adaptive omnidirectional anti-offset wireless charging system for unmanned aerial vehicles provided in an embodiment of the present invention;

[0052] Figure 5 This is a logic diagram for determining the state switching region provided in an embodiment of the present invention;

[0053] Figure 6 This is a comparison chart of calculated values, simulated values, and experimental values ​​provided in the embodiments of the present invention;

[0054] Figure 7 This is a diagram showing the system efficiency variation when no state switching logic is added in the case of an offset, as provided in an embodiment of the present invention.

[0055] Figure 8 The diagram shows the system efficiency change after adding state switching logic in the case of offset, as provided in the embodiment of the present invention.

[0056] Figure 9 This is a flowchart of an adaptive omnidirectional anti-offset wireless charging method for unmanned aerial vehicles provided in an embodiment of the present invention. Detailed Implementation

[0057] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent; to better illustrate the embodiments, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product; it is understandable that those skilled in the art may omit certain well-known structures and their descriptions in the drawings.

[0058] Example 1

[0059] like Figure 1 As shown, an adaptive omnidirectional anti-offset wireless charging system for unmanned aerial vehicles (UAVs) according to the present invention includes: a charging platform and a UAV.

[0060] The charging platform includes a DC power supply, a high-frequency full-bridge inverter circuit, a transmitting coil resonant network, a judging coil resonant network, a drive circuit, and a charging state switching circuit. The DC power supply provides DC power to the entire system, and its output is connected to the input of the high-frequency full-bridge inverter circuit. The output of the high-frequency full-bridge inverter circuit is connected to the charging state switching circuit to provide AC power. The charging state switching circuit is connected to the transmitting coil resonant network and the judging coil resonant network to switch the charging state of the charging platform. At the same time, the charging state switching circuit also establishes a wireless communication channel with the UAV to receive the status signals transmitted by the UAV. The transmitting coil resonant network and the judging coil resonant network are coupled to the UAV for power transmission. The drive circuit generates a PWM signal and converts it into a MOSFET drive signal. The MOSFET drive signal drives the high-frequency full-bridge inverter circuit to invert the DC power input from the DC power supply into AC power of a specified frequency.

[0061] The transmitting coil resonant network includes a transmitting coil and a transmitting compensation topology, and the judging coil resonant network includes a judging coil and a judging compensation topology. The transmitting coil and the judging coil are mutually inductively coupled to the receiving coil in the receiving coil resonant network of the UAV section.

[0062] The charging state switching circuit is used to receive the state signal emitted by the UAV and switch the charging platform to a specified charging state. The charging state switching circuit includes a first MCU control circuit, a first Bluetooth module, and field-effect transistors (FETs). The FETs include a first FET S1, a second FET S2, a third FET S3, a fourth FET S4, and a fifth FET S5. When the first FET S1 and the fourth FET S4 are turned on, and the second FET S2, the third FET S3, and the fifth FET S5 are turned off, the first FET S1 and the fourth FET S4 form a circuit with the transmitting coil resonant network, and the transmitting coil is forward-biased. When the coil is determined to be non-conductive, the transmitting coil transmits electrical energy to the receiving coil. When the second FET S2 and the third FET S3 are turned on, and the first FET S1... When the fourth MOSFET S4 and the fifth MOSFET S5 are turned off, the second MOSFET S2 and the third MOSFET S3 form a circuit with the transmitting coil resonant network, the transmitting coil is reverse-biased, and the judgment coil is not conducting, thus realizing the transmission of electrical energy from the transmitting coil to the receiving coil. When the first MOSFET S1, the second MOSFET S2, the third MOSFET S3, and the fourth MOSFET S4 are turned off, and the fifth MOSFET S5 is turned on, the fifth MOSFET S5 forms a circuit with the judgment coil, the transmitting coil is not conducting, and the judgment coil is forward-biased, thus realizing the transmission of electrical energy from the judgment coil to the receiving coil. The first Bluetooth is used to receive the status signals emitted by the drone. The first MCU control circuit analyzes and processes the status signals emitted by the drone and controls the conduction state of each MOSFET, thereby switching the charging platform to the specified charging state.

[0063] The drone component includes a receiving coil resonant network, a rectifier circuit, a battery charging circuit, and a charging monitoring circuit. The receiving coil resonant network is coupled to the transmitting coil resonant network and the judgment coil resonant network, respectively. The receiving coil resonant network is also connected to the rectifier circuit, which is connected to the battery charging circuit and the charging monitoring circuit, respectively. The charging monitoring circuit transmits a status signal to the charging platform by monitoring the charging status, so as to switch the charging platform to a suitable charging status.

[0064] The receiving coil resonant network includes a receiving coil and a receiving compensation topology. The receiving coil is coupled to the transmitting coil and the judgment coil, respectively.

[0065] The charging monitoring circuit includes a voltage monitoring circuit, a current monitoring circuit, a second MCU control circuit, and a second Bluetooth. The voltage monitoring circuit is connected in parallel with the rectifier circuit, and the current monitoring circuit is connected in series between the rectifier circuit and the battery charging circuit. The voltage monitoring circuit is used to monitor the charging voltage of the drone, and the current monitoring circuit is used to monitor the charging current of the drone. The monitored charging voltage and charging current are analyzed and processed by the second MCU control circuit to obtain the required charging state, and the state signal is sent to the Bluetooth of the charging platform via Bluetooth. The first MCU control circuit controls the charging state switching circuit to perform corresponding actions based on the state data received by the Bluetooth on this side, thereby switching the charging platform to a suitable charging state.

[0066] The coil structure of the adaptive omnidirectional anti-offset drone wireless charging system is as follows: Figure 2 As shown, it includes four parts: a transmitting coil, a judging coil, a receiving coil, and a magnetic core. The receiving coil, judging coil, transmitting coil, and magnetic core are stacked from top to bottom to form the overall structure of the charging system coil.

[0067] The transmitting coil L T1It includes two sets of coils, namely the upper-layer coil and the lower-layer coil. The winding directions of the two are opposite, and they are connected in series; the lower-layer coil is centered on a fifth square coil, and the second square coil, the eighth square coil, the fourth square coil, and the sixth square coil are connected in series in its four directions of up, down, left, and right. The completed series-connected coil is cut along the 45° direction of the upper left vertex, the lower left vertex, and the lower right vertex of the central fifth square coil and the 135° direction of the upper right vertex to form a single loop; the upper-layer coil is centered on a tenth square coil that wraps the central fifth square coil of the lower-layer coil, and the first square coil, the seventh square coil, the third square coil, and the ninth square coil are connected in series in its four directions of upper left, lower left, upper right, and lower right. The completed series-connected coil is cut along the 45° direction of the upper left vertex and the lower right vertex of the central tenth square coil and the 135° direction of the lower left vertex and the upper right vertex to form a single loop; the upper and lower two-layer coils form a hollow nine-square grid shape as a whole, and the current flowing through adjacent squares has opposite directions.

[0068] The judgment coil L T2 It includes two sets of coils, namely the internal coil and the external coil; the internal coil is composed of the eleventh square coil, the twelfth square coil, the thirteenth square coil, and the fourteenth square coil connected in series to form a "field" shape. Each square coil of the internal coil has the same size as each square area in the nine-square grid area of the transmitting coil. It is cut along the 45° and 135° directions at the central position of the internal coil to form a single loop, and the current flowing through each square of the internal coil has the same direction; the external coil is a fifteenth square coil that surrounds the internal coil, and the current flow direction of the external coil is the same as that of the internal coil, and the two sets of internal and external coils are connected in series.

[0069] In this embodiment, the planar sizes of the magnetic core and the transmitting coil are both 300×300 mm. The transmitting coil is spliced by two layers of coils with a thickness of 5 mm. The outer diameters of the first square coil, the third square coil, the seventh square coil, and the ninth square coil are 100 mm, and the inner diameters are 60 mm. The outer diameter of the fifth square coil is 140 mm, and the inner diameter is 100 mm; the outer diameter of the tenth square coil at the center of the upper-layer coil is 100 mm, and the inner diameter is 60 mm. The outer-layer planar sizes of the remaining second square coil, the fourth square coil, the sixth square coil, and the eighth square coil are 120×100 mm, and the inner-layer planar sizes are 100×80 mm; the receiving coil is a circular coil with an outer diameter of 60 mm and an inner diameter of 40 mm; the thicknesses of the magnetic core and the receiving coil are both 5 mm.

[0070] The magnetic core is a ferrite magnetic core of NCD LP9 material, covering the entire transmitting coil area.

[0071] The transmitting coil L T1 is composed of ten small square coils, and the judgment coil L T2The transmitting coil L consists of four small square coils and a square coil surrounding these four small square coils. T1 Determine coil L T2 Receiver coil L R All are DD coils; the eleventh, twelfth, thirteenth, and fourteenth square coils are hollow coils of the same size; the circular coil is a hollow coil with the same inner diameter as the small eleventh, twelfth, thirteenth, and fourteenth square coils.

[0072] The transmitting coil L T1 With receiving coil L R Mutual inductance coupling, transmitting coil L T1 The first end is connected to the receiving coil L R The first terminals are terminals with the same name; the judgment coil L T2 With receiving coil L R Mutual inductance coupling, transmitting coil L T2 The first end is connected to the receiving coil L R The first ends are the same name as each other.

[0073] transmitting coil L T1 The square coils and receiving coil L in the middle R Mutual inductance coefficient, judging coil L T2 The square coils and receiving coil L in the middle R The mutual inductance coefficients can all be calculated using the mutual inductance coefficient calculation formula.

[0074] Among them, the transmitting coil L T1 The square coils and receiving coil L in the middle R The mutual inductance coefficient is calculated using the following formula:

[0075]

[0076] in, Let μj be the mutual inductance between the j-th side of the i-th square coil in the transmitting coil and the receiving coil, μ0 be the free permeability, and aj be the mutual inductance. i Let be the side length of the i-th square coil in the transmitting coil, r be the radius of the receiving coil, and t be the side length of the square coil in the transmitting coil. i Let the center of the i-th square coil in the transmitting coil be along the y-axis with the center of the receiving coil. i The distance of axis offset, h i Let θ be the distance along the z-axis offset between the center of the i-th square coil in the transmitting coil and the center of the receiving coil. i M refers to the angle between the i-th square coil in the transmitting coil and the receiving coil. TRi M refers to the mutual inductance between the i-th square coil in the transmitting coil and the receiving coil. Σ This is the mutual inductance between the transmitting coil and the receiving coil.

[0077] The formula for calculating the mutual inductance coefficient between the square coils and the receiving coil in the coil is as follows:

[0078]

[0079] in, To determine the mutual inductance between the p-th side of the q-th square coil and the receiving coil, μ0 is the free permeability, and a q To determine the side length of the q-th square coil in the coil, where r is the radius of the receiving coil, t q To determine whether the center of the q-th square coil in the coil is aligned with the center of the receiving coil along the y-axis... q The distance of axis offset, h q To determine the distance θ is offset along the z-axis between the center of the q-th square coil and the center of the receiving coil, q This refers to determining the angle between the q-th square coil and the receiving coil in the coil, M. JRq This refers to determining the mutual inductance between the q-th square coil and the receiving coil in the coil, M. JΣ To determine the mutual inductance between the overall coil and the receiving coil.

[0080] Using M T1R The formula is obtained by numerical calculation for transmitting coils of different sizes. Figure 3 The diagram shows the changes in mutual inductance. The size of the receiving coil remains constant, the width K of the transmitting coil remains constant, and only the length L changes. w is the preset length value, and S is the distance the receiving coil moves from one end of the transmitting coil to the other. When K = L, that is, when the transmitting coil is a square coil, the mutual inductance value is the largest. The segment "m~n" in the diagram is selected as the effective charging area segment to ensure that the mutual inductance is relatively stable while ensuring that its value is large.

[0081] The formula shows that during the movement of the receiving coil, the mutual inductance caused by square coils farther away is approximately zero. For example, when the receiving coil is above the first square coil, the mutual inductance between it and the ninth square coil is approximately zero. When the receiving coil is directly above a single square coil, the mutual inductance is mainly affected by the square coil directly below it. For example, when the receiving coil is above the fifth square coil, the mutual inductance between it and the transmitting coil is mainly affected by the fifth square coil. When the receiving coil is in the area between two square coils, the mutual inductance is affected by the two square coils directly below it. For example, when the receiving coil is in the area above the intersection of the fourth and fifth square coils, the mutual inductance between it and the transmitting coil comes from the combined influence of the fourth and fifth square coils. Since the current flowing through the two square coils is in opposite directions, when the center distance between the receiving coil and the two adjacent square coils is the same, the superimposed mutual inductance approaches zero. For example, when the receiving coil is in the area above the intersection of the fourth and fifth square coils... When the receiving coil is at the center, the mutual inductance between it and the transmitting coil comes from the combined influence of the positive and negative magnetic fields of the fourth and fifth square coils, and the superimposed value approaches 0. When the receiving coil is located in the intersection area of ​​four adjacent square coils, the mutual inductance value is affected by the four square coils below it. For example, when the receiving coil is located in the intersection area above the first, second, fourth, and fifth square coils, the mutual inductance between it and the transmitting coil comes from the combined influence of the first, second, fourth, and fifth square coils. When the center distance between the receiving coil and the four adjacent square coils is the same, since the current flowing through the two pairs of diagonally opposite square coils is in opposite directions, the superimposed mutual inductance value approaches 0. For example, when the receiving coil is located at the exact center of the intersection area above the first, second, fourth, and fifth square coils, the mutual inductance between it and the transmitting coil comes from the combined influence of the positive and negative magnetic fields of the first, second, fourth, and fifth square coils, and the superimposed value approaches 0. This indicates that using this coil design method will cause the receiving coil to cross zero during its movement, and calculation and analysis using formulas can show that the mutual inductance value will switch between positive and negative.

[0082] To solve the problems of zero crossing and positive / negative switching, improvements need to be made in the following two aspects: (1) When the receiving coil moves above the second square coil, fourth square coil, sixth square coil and eighth square coil which are opposite to the current flow direction of the transmitting coil, the current direction of the transmitting coil as a whole needs to be switched to ensure that the current flow direction of the transmitting coil in the area where the receiving coil is located is always consistent with that of the receiving coil; (2) Add a transition section to raise the mutual inductance curve and keep it in a relatively stable region.

[0083] The circuit structure of the adaptive omnidirectional anti-displacement UAV wireless charging system is as follows: Figure 4 As shown;

[0084] The field-effect transistors include a first field-effect transistor S1, a second field-effect transistor S2, a third field-effect transistor S3, a fourth field-effect transistor S4, and a fifth field-effect transistor S5. All five transistors are N-channel enhancement-type MOSFETs of the same type. The drain of the first field-effect transistor S1 is connected to the source of the first power switch D1, the source of the first field-effect transistor S1 is connected to the drain of the third field-effect transistor S3, and the source of the third field-effect transistor S3 is connected to the gate of the fourth power switch D4. The drain of the second field-effect transistor S2... The first field-effect transistor S1 is connected to the source of the first power switch D1, the second field-effect transistor S2 is connected to the drain of the fourth field-effect transistor S4, and the source of the fourth field-effect transistor S4 is connected to the gate of the fourth power switch D4; the drain of the fifth field-effect transistor S5 is connected to the source of the first power switch D1, and the source of the fifth field-effect transistor S5 is connected to the resonant network of the judgment coil as the other end; the gates of the first field-effect transistor S1, the second field-effect transistor S2, the third field-effect transistor S3, the fourth field-effect transistor S4, and the fifth field-effect transistor S5 are all connected to the first MCU control circuit, and the first MCU control circuit establishes a communication connection with the first Bluetooth.

[0085] The transmitting coil resonant network includes the transmitting coil L T1 and launch compensation topology C T1 transmitting coil L T1 and launch compensation topology C T1 Series connection, transmitting coil L T1 The other end is connected to the source of the first field-effect transistor S1 and the drain of the third field-effect transistor S3, forming the emitter compensation topology C. T1 The other end is connected to the source of the second field-effect transistor S2 and the drain of the fourth field-effect transistor S4.

[0086] The network for determining coil resonance includes determining coil L. T2 and judgment compensation topology C T2 Determine coil L T2 and judgment compensation topology C T2 Series connection, determine coil L T2 The other end is connected to the source of the third field-effect transistor S3 and the fourth field-effect transistor S4, determining the compensation topology C. T2 The other end is connected to the source of the fifth field-effect transistor S5.

[0087] The receiving coil resonant network includes the receiving coil L R and receiving compensation topology C R Receiving coil L R and receiving compensation topology C R Series connection, receiving coil L RThe other end and receiving compensation topology C R The other end is connected to the input of the rectifier circuit, the battery charging circuit is connected in parallel to the output of the rectifier circuit, the current monitoring circuit is connected in series between the rectifier circuit and the battery charging circuit, and the voltage monitoring circuit is connected in parallel with the rectifier circuit. The voltage monitoring circuit is used to monitor the charging voltage of the UAV, and the current monitoring circuit is used to monitor the charging current. The monitored charging voltage and charging current are calculated by the second MCU control circuit to obtain the charging output power P. out Combined with the preset input power P in The charging efficiency η can be calculated by the second MCU control circuit, the required charging state can be determined, and the state data can be sent to the charging platform via Bluetooth. The first MCU control circuit controls the charging state switching circuit to perform corresponding actions based on the received state data, thereby realizing the switching of charging state.

[0088] In practical applications, the load R is much larger than the internal resistance R1 generated by the resonant networks of the transmitting coil and the judging coil, and the internal resistance R2 generated by the resonant network of the receiving coil. Therefore, the system's charging power P and charging efficiency η can be expressed by the following formulas:

[0089]

[0090] Among them, U S ω is the equivalent AC power supply voltage after inversion by the high-frequency full-bridge inverter circuit, and ω is the resonant frequency.

[0091] The charging state switching circuit includes three charging states, such as... Figure 1 and Figure 2 As shown, in charging state 1, S1 and S4 are closed, and S2, S3, and S5 are open. Figure 5 The current flow direction of the transmitting coil in regions ①③⑤⑦⑨ is the same as that of the receiving coil. When the transmitting coil is located in these five regions, the charging state is switched to state 1. In charging state 2, S2 and S3 are closed, and S1, S4, and S5 are open. Figure 5 The current flow direction of the transmitting coil in regions ②④⑥⑧ is the same as that of the receiving coil. When the transmitting coil is located in these four regions, the charging state is switched to state 2. In charging state 3, S1 to S4 are all open and S5 is closed. At this time, the charging platform charges the drone by judging the coil, and the transmitting coil is not conducting. Figure 5 The positions of regions ①②③④ correspond to the first square coil, the second square coil, the third square coil, and the fourth square coil, respectively. The position of region ⑤ corresponds to the fifth square coil and the tenth square coil, respectively. The positions of regions ⑥⑦⑧⑨ correspond to the sixth square coil, the seventh square coil, the eighth square coil, and the ninth square coil, respectively.

[0092] When the charging efficiency η calculated by the second MCU control circuit of the drone is greater than the first preset charging efficiency threshold η A At this time, the horizontal position of the receiving coil is located in region ⑤ of the transmitting coil. Charging the UAV using charging state 1 can achieve the maximum transmission efficiency. Therefore, when the charging efficiency calculated by the monitoring circuit is greater than η... A At this time, the drone's Bluetooth sends a status signal to the charging platform's Bluetooth. Upon receiving the status signal, the charging platform's Bluetooth sends it to the first MCU control circuit. The first MCU control circuit then turns on S1 and S4 and turns off S2, S3, and S5. At this point, the charging platform switches to charging state I. When the charging efficiency η is greater than the second preset charging efficiency threshold η... B And less than the first preset charging efficiency threshold η A At this time, due to the influence of magnetic field strength, the charging efficiency of the transmitting coil in the area where the drone is located is much lower than that of the judgment coil. Therefore, it is necessary to turn on S5 and turn off S1 to S4 to switch to charging state III; when the charging efficiency η is greater than the third preset charging efficiency threshold η C And less than the second preset charging efficiency threshold η B At this time, the receiving coil is located in the areas ②, ④, ⑥, and ⑧ of the transmitting coil. To reduce mutual inductance fluctuations, S2 and S3 should be turned on, and S1, S4, and S5 should be turned off. The transmitting coil should be turned on in the reverse direction so that the current flow in the area is consistent with that of the receiving coil, and the charging state II should be switched. When η is less than the third preset charging efficiency threshold η C When the receiving coil is in areas ①, ③, ⑦, or ⑨ of the transmitting coil or at the edge of the charging platform, if it is still within the effective charging area, switching the platform to charging state Ⅰ can achieve greater charging efficiency. If it is at the edge of the charging platform, the deviation is too large and it is not considered.

[0093] By combining numerical calculations with simulation analysis and experimental verification, we can obtain results such as Figure 6 The transmission efficiency variation graph shown shows that the transmission efficiency remains basically stable when the receiving coil is offset. The simulation and experimental parameters are shown in Table 1.

[0094] Table 1 Performance parameters of the magnetic coupling mechanism

[0095]

[0096] like Figure 7 As shown, without state switching, the transmission efficiency before and after the receiving coil offset differs by 66 times. At this time, the effective charging section has good charging efficiency, but the transition section cannot effectively transmit power, and the anti-offset characteristics are extremely poor.

[0097] like Figure 8As shown, after adding the state switching logic, the transmission efficiency before and after the receiving coil offset differs by a factor of 0.93. Clearly, adding the state switching logic significantly improves the mutual inductance fluctuations between coils when the receiving coil is offset, keeping the transmission efficiency and power changes within a very small range, and significantly improving the overall system efficiency and anti-offset capability.

[0098] like Figure 9 As shown, the adaptive omnidirectional anti-offset wireless charging method for drones includes the following steps:

[0099] S1: Initialize the system. The drive circuit generates a MOSFET drive signal to drive the high-frequency full-bridge inverter circuit to convert the DC power input into AC power of a specified frequency. The fifth field-effect transistor is turned on, and the coil is judged to enter the working state.

[0100] S2: The drone flies into the charging platform, where a detection coil pre-charges it. The drone's second MCU control circuit determines the required charging state based on the charging efficiency and transmits the status data to the charging platform's charging state switching circuit via Bluetooth. Specifically:

[0101] The voltage monitoring circuit is used to monitor the charging voltage, and the current monitoring circuit is used to monitor the charging current. The charging voltage and charging current are then output to the second MCU control circuit.

[0102] The second MCU control circuit analyzes and processes the charging voltage and charging current, and calculates the output power P of the charger. out Combined with the preset input power P in The charging efficiency η can be calculated by the second MCU control circuit, and the required charging state can be determined. The method for determining the charging state is as follows:

[0103] (1) Judgment η>η A If the condition is true, output the character "State I", indicating that the required charging state is State I, and execute step (4); otherwise, execute step (2).

[0104] (2) Judgment η>η B If the condition is true, output the character "State III", indicating that the required charging state is State III, and execute step (4); otherwise, execute step (3).

[0105] (3) Judgment η>η C If the condition is true, output the character "State II", indicating that the required charging state is State II, and execute step (4); if not, output the character "State I", indicating that the required charging state is State I, and execute step (4).

[0106] (4) The second MCU control circuit uploads the status information corresponding to the output character to the second Bluetooth, and transmits the status information to the first MCU control circuit of the charging platform section through the communication channel between the second Bluetooth and the first Bluetooth.

[0107] S3: After receiving the status information data, the first MCU control circuit of the charging platform controls the first field-effect transistor S1, the second field-effect transistor S2, the third field-effect transistor S3, the fourth field-effect transistor S4, and the fifth field-effect transistor S5 to perform corresponding actions to switch the charging state and complete the omnidirectional anti-offset operation of the drone wireless charging system; specifically:

[0108] When the status information is "Status I", the first MCU control circuit controls the first field-effect transistor S1 and the fourth field-effect transistor S4 to be turned on, and controls the second field-effect transistor S2, the third field-effect transistor S3 and the fifth field-effect transistor S5 to be turned off. At this time, the charging platform switches to charging status I.

[0109] When the status information is "Status II", the first MCU control circuit controls the second field-effect transistor S2 and the third field-effect transistor S3 to be turned on, and the first field-effect transistor S1, the fourth field-effect transistor S4 and the fifth field-effect transistor S5 to be turned off, and the transmitting coil is turned on in reverse, and the charging platform switches to charging status II.

[0110] When the status information is "Status III", the first MCU control circuit controls the fifth field-effect transistor S5 to be turned on, and the first field-effect transistor S1 to the fourth field-effect transistor S4 are turned off. The charging platform switches to charging status III. At this time, the charging platform charges the drone by judging the coil, and the transmitting coil is not turned on.

[0111] This method can balance the system's anti-offset characteristics and overall transmission efficiency, and has higher application value.

[0112] The same or similar reference numerals correspond to the same or similar parts; the descriptions of positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0113] Obviously, the above examples of the present invention are merely illustrative of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An adaptive omnidirectional anti-drift unmanned aerial vehicle wireless charging system, characterized in that, The application relates to a wireless charging system for unmanned aerial vehicles, which comprises a charging platform part and an unmanned aerial vehicle part, the charging platform part comprises a power supply module, a charging state switching circuit, a transmitting coil resonant network and a judging coil resonant network, the charging state switching circuit comprises a first MCU control circuit, a first switching circuit, a second switching circuit and a third switching circuit, the transmitting coil resonant network comprises a transmitting coil and a transmitting compensation topology, and the judging coil resonant network comprises a judging coil and a judging compensation topology; the unmanned aerial vehicle part comprises a receiving coil resonant network, a rectifier circuit, a battery charging circuit and a charging monitoring circuit, the receiving coil resonant network comprises a receiving coil and a receiving compensation topology; the power supply module is used for providing electric energy for the whole system, the transmitting coil and the judging coil are inductively coupled with the receiving coil respectively, are used for realizing the transmission of electric energy from the wireless charging platform part to the unmanned aerial vehicle part, the output electric energy of the receiving coil resonant network flows into the battery charging circuit for charging the unmanned aerial vehicle after passing through the rectifier circuit, the charging monitoring circuit is used for monitoring the output of the receiving coil resonant network and judging the required charging state of the unmanned aerial vehicle according to the monitoring data, and simultaneously transmitting the state information to the first MCU control circuit; the first MCU control circuit controls the working states of the first switching circuit, the second switching circuit and the third switching circuit according to the state information, and further controls the coupling states of the transmitting coil, the judging coil and the receiving coil, realizes the switching of the charging state and completes the omnidirectional anti-offset wireless charging operation of the unmanned aerial vehicle wireless charging system. The charging state switching circuit comprises three charging states: When the state I, the first switching circuit is in the working state, the second switching circuit and the third switching circuit are not worked, the transmitting coil is forwardly conducted, the judging coil is not conducted, and the transmitting coil transmits electric energy to the receiving coil; When the state II, the second switching circuit is in the working state, the first switching circuit and the third switching circuit are not worked, the transmitting coil is reversely conducted, the judging coil is not conducted, and the transmitting coil transmits electric energy to the receiving coil; When the state III, the third switching circuit is in the working state, the first switching circuit and the second switching circuit are not worked, the transmitting coil is not conducted, the judging coil is forwardly conducted, and the judging coil transmits electric energy to the receiving coil; The relationship between the monitoring data and the charging state is that the charging monitoring circuit obtains the charging efficiency eta according to the monitoring data; The power supply module comprises a direct current power supply, a high-frequency full-bridge inverter circuit and a driving circuit, the driving circuit is used for generating a PWM signal and converting the PWM signal into a MOSFET driving signal to drive the high-frequency full-bridge inverter circuit to inversely change the direct current input by the direct current power supply into alternating current of a specified frequency, and provide electric energy for the system. η > η A when η A is the first preset charging efficiency threshold value, and the required charging state of the unmanned aerial vehicle is state I. η B <η<η A when, η B is the second preset charging efficiency threshold value, and the required charging state of the unmanned aerial vehicle is state III. η C <η<η B η C is a third preset charging efficiency threshold value, and the required charging state of the unmanned aerial vehicle is state II. η < η C When the battery level is between 20% and 40%, the required charging state of the UAV is: state I.

2. The adaptive omnidirectional anti-offset unmanned aerial vehicle wireless charging system according to claim 1, wherein, ​ 3. The adaptive omnidirectional anti-offset unmanned aerial vehicle wireless charging system according to claim 1, wherein, The transmitting coil includes an upper-layer coil and a lower-layer coil, with their winding directions opposite to each other, and they are connected in series; the lower-layer coil is centered on a fifth square coil, and the second square coil, the eighth square coil, the fourth square coil, and the sixth square coil are respectively connected in series in its four directions of up, down, left, and right. The completed series-connected coil is cut along the 45° directions of the upper left vertex, the lower left vertex, and the lower right vertex of the central fifth square coil and the 135° direction of the upper right vertex to form a single loop; the upper-layer coil is centered on a tenth square coil that encloses the central fifth square coil of the lower-layer coil, and the first square coil, the seventh square coil, the third square coil, and the ninth square coil are respectively connected in series in its four directions of upper left, lower left, upper right, and lower right. The completed series-connected coil is cut along the 45° directions of the upper left vertex and the lower right vertex of the central tenth square coil and the 135° directions of the lower left vertex and the upper right vertex to form a single loop; the upper and lower coils as a whole form a hollow nine-square grid shape, and the current flowing through adjacent squares has opposite directions.

4. The adaptive omnidirectional anti-offset unmanned aerial vehicle wireless charging system according to claim 3, wherein, The first end of the transmitting coil and the first end of the receiving coil are homologous ends, and the calculation formula for the mutual inductance coefficient of each square coil in the transmitting coil and the receiving coil is: wherein, Mijis the mutual inductance value between the jth side of the ith square coil in the transmit coil and the receive coil, μ0is the vacuum permeability, a i ais the side length of the ith square coil in the transmit coil, r is the radius of the receive coil, t i is the distance between the center of the ith square coil in the transmit coil and the center of the receive coil along the y i axis, h i is the distance between the center of the ith square coil in the transmit coil and the center of the receive coil along the z axis, θ i denotes the angle between the ith square coil in the transmit coil and the receive coil, M TRi denotes the mutual inductance between the ith square coil in the transmit coil and the receive coil, M Σ is the mutual inductance value between the entire transmit coil and the receive coil.

5. The adaptive omnidirectional anti-offset unmanned aerial vehicle wireless charging system of claim 1, wherein, The judgment coil includes an internal coil and an external coil. The internal coil is composed of an eleventh square coil, a twelfth square coil, a thirteenth square coil, and a fourteenth square coil connected in series to form a "field" shape. Each square coil of the internal coil has the same size as each square area in the nine-square grid area of the transmitting coil. It is cut along the 45° and 135° directions at the central position of the internal coil to form a single loop, and the current flowing through each square of the internal coil has the same direction; the external coil is a fifteenth square coil that encloses the internal coil, and the current direction of the external coil is the same as that of the internal coil, and the two sets of internal and external coils are connected in series.

6. The adaptive omnidirectional anti-offset unmanned aerial vehicle wireless charging system according to claim 5, wherein, The first end of the judgment coil and the first end of the receiving coil are homologous ends, and the calculation formula for the mutual inductance coefficient of each square coil in the judgment coil and the receiving coil is: wherein, Mpqis the mutual inductance value between the pth side of the qth square coil in the judgment coil and the receiving coil, μ0is the vacuum permeability, a q is the side length of the qth square coil in the judgment coil, r is the radius of the receiving coil, t q is the distance of the center of the qth square coil in the judgment coil and the center of the receiving coil along the y q axis, h q is the distance of the center of the qth square coil in the judgment coil and the center of the receiving coil along the z axis, θ q refers to the angle between the qth square coil in the judgment coil and the receiving coil, M JRq refers to the mutual inductance between the qth square coil in the judgment coil and the receiving coil, M JΣ is the mutual inductance value between the entire judgment coil and the receiving coil.

7. The adaptive omnidirectional anti-offset unmanned aerial vehicle wireless charging system of claim 1, wherein, The receiving coil, the judgment coil, and the transmitting coil are stacked in sequence from top to bottom to form an overall structure, and a magnetic core is stacked below the transmitting coil; the receiving coil is a circular coil, and the magnetic core covers the entire area of the transmitting coil.

8. The adaptive omnidirectional anti-offset unmanned aerial vehicle wireless charging system of claim 1, wherein, The first switching circuit includes a first field-effect transistor S1 and a fourth field-effect transistor S4, the second switching circuit includes a second field-effect transistor S2 and a third field-effect transistor S3, and the third switching circuit includes a fifth field-effect transistor S5; When the first field effect transistor S1 and the fourth field effect transistor S4 are turned on, and the second field effect transistor S2, the third field effect transistor S3 and the fifth field effect transistor S5 are turned off, the first field effect transistor S1 and the fourth field effect transistor S4 form a loop with the transmitting coil resonant network, the transmitting coil is turned on in the forward direction, the judging coil is turned off, and the transmitting coil transmits electric energy to the receiving coil; when the second field effect transistor S2 and the third field effect transistor S3 are turned on, and the first field effect transistor S1, the fourth field effect transistor S4 and the fifth field effect transistor S5 are turned off, the second field effect transistor S2 and the third field effect transistor S3 form a loop with the transmitting coil resonant network, the transmitting coil is turned on in the reverse direction, the judging coil is turned off, and the transmitting coil transmits electric energy to the receiving coil; when the first field effect transistor S1, the second field effect transistor S2, the third field effect transistor S3 and the fourth field effect transistor S4 are turned off, and the fifth field effect transistor S5 is turned on, the fifth field effect transistor S5 forms a loop with the judging coil, the transmitting coil is turned off, the judging coil is turned on in the forward direction, and the judging coil transmits electric energy to the receiving coil; The charging state switching circuit further comprises a first Bluetooth, which is configured to receive a state signal sent by the UAV, and the first MCU control circuit is configured to analyze and process the received state signal, control the conduction states of the first field effect transistor S1, the second field effect transistor S2, the third field effect transistor S3, the fourth field effect transistor S4 and the fifth field effect transistor S5, and further switch the charging platform to a specified charging state.

9. The adaptive omnidirectional anti-offset unmanned aerial vehicle wireless charging system of claim 1, wherein, The charging monitoring circuit comprises a voltage monitoring circuit, a current monitoring circuit, a second MCU control circuit and a second Bluetooth, the voltage monitoring circuit is connected in parallel with the battery charging circuit, and the current monitoring circuit is connected in series between the rectifier circuit and the battery charging circuit; the voltage monitoring circuit and the current monitoring circuit are configured to monitor the charging voltage and the charging current of the UAV respectively, and transmit the charging voltage and the charging current to the second MCU control circuit, the second MCU control circuit is configured to analyze and process the charging voltage and the charging current of the UAV to obtain the required charging state of the UAV, and send a state signal to the charging platform part through the second Bluetooth.

10. An adaptive omnidirectional anti-drone wireless charging method, characterized in that, The method comprises the following steps: S1, initializing the system, the driving circuit generates a MOSFET driving signal to drive the high-frequency full-bridge inverter circuit to convert the direct current input by the direct current power supply into alternating current of a specified frequency, turn on the fifth field effect transistor, and make the judging coil enter a working state; S2, the UAV flies into the charging platform, and the judging coil precharges the UAV, the second MCU control circuit of the UAV part determines the required charging state according to the charging efficiency, and transmits state data to the charging state switching circuit of the charging platform part; Specifically, The voltage monitoring circuit is configured to monitor the charging voltage, and the current monitoring circuit is configured to monitor the charging current, and output the charging voltage and the charging current to the second MCU control circuit; The second MCU control circuit analyzes and processes the charging voltage and the charging current, and calculates the output power P of the charging out , in combination with the preset input power P in , to obtain the charging efficiency η through the second MCU control circuit, and to determine the required charging state; the charging state determination method is: (1) determine if η > η A If yes, output the character "state I", i.e. the required charging state is state I, and perform step (4); if no, perform step (2); (2) determine if η > η B is true, then output the character "state III", i.e. the required charging state is state III, and perform step (4); if not, then perform step (3); (3) determine if η > η C is true, the character "state II" is output, i.e. the required charging state is state II, and step (4) is executed; if not, the character "state I" is output, i.e. the required charging state is state I, and step (4) is executed; (4) the second MCU control circuit transmits the state information corresponding to the output character to the first MCU control circuit of the charging platform part; S3, the first MCU control circuit of the charging platform part receives the state information data, controls the first field effect tube S1, the second field effect tube S2, the third field effect tube S3, the fourth field effect tube S4 and the fifth field effect tube S5 to execute corresponding actions to realize the switching of the charging state, and completes the omnidirectional anti-offset operation of the unmanned aerial vehicle wireless charging system; Specifically: When the state information is "state I", the first MCU control circuit controls the first field effect tube S1 and the fourth field effect tube S4 to be turned on, and controls the second field effect tube S2, the third field effect tube S3 and the fifth field effect tube S5 to be turned off, at this time, the charging platform is switched to the charging state I; When the state information is "state II", the first MCU control circuit controls the second field effect tube S2 and the third field effect tube S3 to be turned on, and controls the first field effect tube S1, the fourth field effect tube S4 and the fifth field effect tube S5 to be turned off, reversely turns on the transmitting coil, and the charging platform is switched to the charging state II; When the state information is "state III", the first MCU control circuit controls the fifth field effect tube S5 to be turned on, and controls the first field effect tube S1 to the fourth field effect tube S4 to be turned off, the charging platform is switched to the charging state III, at this time, the charging platform charges the unmanned aerial vehicle through the judgment coil, and the transmitting coil is not turned on.

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