Anti-offset unmanned aerial vehicle wireless charging system based on PT symmetry and parameter design method

Abstract

The invention provides a parameter design method of an anti-offset unmanned aerial vehicle wireless charging system based on PT symmetry. The method is used for solving the problems of magnetic coupling coefficient change and unstable system transmission performance caused by position offset in a wireless charging process of an existing unmanned aerial vehicle. The system comprises a transmitting end and a receiving end, wherein the receiving end comprises a first receiving coil, a second receiving coil and a third receiving coil which are sequentially connected in series; the first receiving coil, the second receiving coil and the third receiving coil are all planar coils, the included angle between the first receiving coil and the second receiving coil and the included angle between the third receiving coil and the second receiving coil are adjustable, and the included angle between the first receiving coil and the second receiving coil and the included angle between the third receiving coil and the second receiving coil are all larger than 90 degrees and smaller than or equal to 180 degrees. According to the invention, the capturing area of effective magnetic flux is expanded by arranging the three receiving coils which are connected in series, so that the PT symmetrical working area of the system is expanded cooperatively, and the system can maintain constant transmission efficiency and power when offset occurs.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission, and in particular to a parameter design method for an anti-offset wireless charging system for unmanned aerial vehicles based on PT symmetry. Background Technology

[0002] Drones, with their flexibility and maneuverability, are widely used in disaster relief, environmental monitoring, agricultural plant protection, and power line inspection. As application scenarios expand and task complexity increases, higher demands are placed on drones' endurance, operational radius, and continuous working time. However, currently, drones primarily rely on onboard batteries with limited capacity for power, requiring frequent interruptions for recharging during missions. This severely reduces operational efficiency and limits the widespread adoption of drones.

[0003] Against this backdrop, magnetically coupled wireless power transfer (MC-WPT) technology offers an innovative power supply method for drones due to its non-physical connection capability. This technology enables drones to flexibly replenish energy, extend flight time, and reduce maintenance and operational complexity. However, for traditional magnetic resonance-based MC-WPT systems, energy efficiency drops sharply when the transmission distance or direction deviates from the optimal point, requiring additional tuning methods to achieve stable energy transfer within a certain range and direction. Common methods include parameter estimation, impedance matching, and dynamic parameter adjustment. However, these methods face significant limitations in drone wireless charging applications. On one hand, drones, as receivers, are extremely weight-sensitive; complex auxiliary control circuits and switchable components increase system weight, reducing payload and flight performance. On the other hand, some methods rely on wireless communication with the transmitter for coordinated control; in complex electromagnetic environments or harsh weather conditions, the communication link may be unreliable, affecting the stability and robustness of the energy transfer process.

[0004] To address the aforementioned issues, existing research has introduced parity-time (PT) symmetry theory into WPT systems, proposing PT-symmetric WPT systems. This system maintains constant transmission efficiency and power within the PT symmetry region, eliminating the need for bilateral communication and feedback control. Subsequently, existing research has proposed a PT-WPT system that uses a self-excited oscillation-controlled inverter to replace the operational amplifier in the negative resistance circuit, expanding the application scenarios of PT-WPT systems to medium- and high-power applications. However, the PT-WPT system only possesses constant transmission characteristics independent of the coupling coefficient within the PT symmetry region; therefore, it is necessary to further extend the PT symmetry region to increase the transmission distance. Currently, the main methods for extending the transmission distance of WPT systems are as follows: One method is to extend the transmission distance by adding repeater coils. However, this method occupies a significant amount of space along the power transmission path, thus limiting its practical application. Another method is to use magnetic materials, such as ferrite, to enhance the coupling between coils, thereby increasing the effective transmission range. However, most magnetic materials cause magnetic losses and increase the system's size and weight. Summary of the Invention

[0005] The purpose of this invention is to provide a parameter design method for an anti-offset wireless charging system for unmanned aerial vehicles (UAVs) based on PT symmetry. This method addresses the technical problem of unstable system transmission performance caused by changes in magnetic coupling coefficient due to positional offset during wireless charging in existing UAVs.

[0006] First, this application provides a PT-symmetric anti-offset wireless charging system for unmanned aerial vehicles, including a transmitter and a receiver. The receiver includes a receiving coil module, which includes a first receiving coil, a second receiving coil, and a third receiving coil connected in series.

[0007] The first, second and third receiving coils are all planar coils. The angle between the first and third receiving coils and the second receiving coil is adjustable. The angle between the first and third receiving coils and the second receiving coil satisfies the following conditions: greater than 90° and less than or equal to 180°.

[0008] Optionally, the transmitting end includes a DC power supply, a high-frequency inverter, a primary-side compensation circuit and a transmitting coil connected in sequence, as well as a control circuit disposed between the output end and the control end of the high-frequency inverter.

[0009] The control circuit includes a current sampling module, a zero-crossing comparison module, and a drive module. The current sampling module is used to collect the output current of the high-frequency inverter and transmit it to the zero-crossing comparison module. The zero-crossing comparison module is used to determine the zero-crossing signal based on the current signal and feed it back to the drive module. The drive module is used to generate a corresponding drive signal to control the switching transistors of the high-frequency inverter in real time.

[0010] Optionally, the second receiving coil is located at the bottom of the drone fuselage;

[0011] The first and third receiving coils are respectively mounted on two mounting plates, which are rotatably mounted on the landing gears on both sides of the UAV. The landing gears are equipped with drive modules for driving the mounting plates to rotate.

[0012] Optionally, the receiver may further include a secondary-side compensation circuit and a UAV payload connected in sequence, with the input of the secondary-side compensation circuit connected to the receiving coil module.

[0013] Optionally, the high-frequency inverter is a single-phase full-bridge inverter.

[0014] Optionally, the primary-side compensation circuit and the secondary-side compensation circuit are in an SS topology.

[0015] Optionally, the self-inductance of the receiving coil module is: L s = L s1 + L s2 +L s3 +2(M 12 +M 13 + M 23 ), the L s1 L s2 and L s3 The self-inductances of the first, second, and third receiving coils, respectively, M 12 M 13 and M 23 These are the mutual inductances between the three receiving coils.

[0016] Optionally, the system satisfies: the coupling coefficient k is greater than or equal to the critical coupling coefficient k. c The critical coupling coefficient In the formula: R s For the equivalent load of the receiving end, C s This represents the value of the secondary-side compensation capacitor in the secondary-side compensation circuit.

[0017] A parameter design method for an anti-offset wireless charging system for unmanned aerial vehicles (UAVs) based on PT symmetry, characterized in that it is applied to the aforementioned anti-offset wireless charging system for UAVs based on PT symmetry, and the specific steps are as follows:

[0018] S1: Determine the parameters of the transmitting coil and the first, second and third receiving coils, as well as the DC power supply output voltage, based on the UAV's load and power transmission level parameters and installation dimensions;

[0019] S2: Based on the coil parameters and output voltage parameters obtained in step S1, determine the compensation capacitor values ​​in the primary and secondary compensation circuits using simulation tools;

[0020] S3: Collect the load power of the system operating in the PT symmetrical region at multiple angles using the first and third receiving coils;

[0021] S4: After the drone lands, the receiver load power is collected. Based on the load power, it is determined whether the system is operating in the PT symmetry region. If so, the drone load is charged. If not, the angle of the first receiving coil and / or the third receiving coil is adjusted to make the system operate in the PT symmetry region.

[0022] Optionally, the load power P of the system operating in the PT symmetric region L for: In the formula: R p and R s For the transmitter load and receiver load, L p and L S For the self-inductance of the transmitting coil and the self-inductance of the receiving coil module, U AB The output voltage at the transmitting end is changed.

[0023] Because of the adoption of the above technical solution, the present invention has the following advantages:

[0024] 1. This application expands the effective magnetic flux capture area by setting three series-connected receiving coils, thereby synergistically expanding the PT symmetrical operating area of ​​the system. When an offset occurs, the system can maintain constant transmission efficiency and power.

[0025] 2. This application sets the first and third receiving coils to an adjustable structure. When the UAV landing deviates significantly and the initial angles of the first and third receiving coils do not meet the PT symmetrical operation, the system can maintain constant transmission efficiency and power by adjusting the angles of the first and third receiving coils, which can effectively enhance the robustness of the UAV WPT system to position deviation.

[0026] 3. This application increases the system's output power by setting up three series-connected receiving coils, thereby increasing the equivalent inductance of the receiving end.

[0027] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0028] The accompanying drawings of this invention are described below.

[0029] Figure 1 This is a schematic diagram of the anti-offset wireless charging system for unmanned aerial vehicles based on PT symmetry according to the present invention.

[0030] Figure 2 This is a three-dimensional structural diagram of the MC-WPT system for unmanned aerial vehicles (UAVs) of the present invention.

[0031] Figure 3 This is a diagram showing the relationship between the critical coupling coefficient and the inductance of the receiving coil module in this invention.

[0032] Figure 4 This is a diagram showing the relationship between the load power and the inductance of the receiving coil module in this invention.

[0033] Figure 5 This is a diagram showing the magnetic field lines distribution of the coil structure of the present invention.

[0034] Figure 6 This is the equivalent circuit diagram of the distributed receiving coil module of the present invention.

[0035] Figure 7 This is a graph showing how the coupling coefficient of the present invention changes with the transmission distance.

[0036] Figure 8 This is an energy efficiency curve diagram of different receiving coil structures of the present invention. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] Example 1:

[0039] This embodiment provides a PT-symmetric anti-offset wireless charging system for drones, such as... Figure 1 As shown, it includes a transmitter and a receiver. The transmitter includes a DC power supply, a high-frequency inverter, a primary-side compensation circuit, and a transmitting coil L connected in sequence. p And the control circuit set between the output end and the control end of the high-frequency inverter;

[0040] The receiving coil module L connected in sequence at the receiving end s Secondary-side compensation circuit and UAV load R L .

[0041] like Figure 1 As shown, the control circuit includes a current sampling module, a zero-crossing comparison module, and a drive module. The current sampling module collects the output current of the high-frequency inverter and transmits it to the zero-crossing comparison module. The zero-crossing comparison module determines the zero-crossing signal based on the current signal and feeds it back to the drive module. The drive module generates a corresponding drive signal to control the switching of the high-frequency inverter's transistors in real time, forming a negative resistor -R. g Provides gain.

[0042] In this embodiment, as Figure 1As shown, the high-frequency inverter is a single-phase full-bridge inverter, and the primary-side compensation circuit and the secondary-side compensation circuit are in an SS topology. The primary-side compensation circuit and the secondary-side compensation circuit each include a primary-side compensation capacitor C. p and secondary side compensation capacitor C s , Figure 1 Chinese: R p1 and R p2 M represents the equivalent resistance of the transmitting and receiving coil modules, and L represents the transmitting coil resistance. p With receiving coil module L s Mutual intuition between them, R L For the equivalent payload of the drone, I p I is the output current of the inverter. s This represents the current flowing through the receiving coil module.

[0043] In this embodiment, the system equations are established based on Kirchhoff's voltage law:

[0044] (1)

[0045] in: , , , , , Let be the operating angular frequency of the system, then the input impedance of the system is:

[0046] (2)

[0047] At the PT-symmetric operating point, the system exhibits an equilibrium state where gain and loss are equal. For circuits containing negative resistance, this means the imaginary part of the equivalent input impedance is zero, and the real part satisfies a specific relationship:

[0048] (3)

[0049] At that time, the circuit parameters satisfy:

[0050] (4)

[0051] The system operating frequency and corresponding parameter conditions can be obtained, specifically expressed as:

[0052] (5)

[0053] in: The coupling coefficient is... Let be the critical coupling coefficient of the system, when When the operating frequency has a solution, the effective transmission range of the system is: .

[0054] Furthermore, the system current gain can be obtained:

[0055] (6)

[0056] The receiver load power can be expressed as:

[0057] (7)

[0058] Among them: U AB The output voltage at the transmitting end is changed.

[0059] The system efficiency is:

[0060] (8)

[0061] The above analysis shows that when the system operates in the PT-symmetric region, its output power and transmission efficiency remain constant and are independent of changes in the coupling coefficient. It maintains stable energy transmission performance when faced with changes in transmission distance or lateral offset, exhibiting good offset robustness. Therefore, expanding the PT-symmetric region is crucial for improving the system's actual offset resistance.

[0062] Expanding the PT-symmetric region is a collaborative optimization process; on the one hand, it can reduce [the impact of parameter optimization]. The critical value; on the other hand, by optimizing the receiver structure to enhance the flux trapping capability, a high coupling coefficient is maintained when actual offset occurs. Optimize and expand both aspects simultaneously. The range.

[0063] The above analysis shows that, The value of is related to the inductance of the receiving coil module. Closely related, the relationship between the two is as follows Figure 3 As shown, in the MC-WPT system, the quality factor Q of each loop is usually high (i.e., This application mainly considers The typical work area. For example... Figure 3 As shown, the self-inductance of the receiving coil The larger the critical coupling coefficient, the higher the critical coupling coefficient. The smaller the value, the larger the corresponding PT symmetric region (the gray shaded area in the figure), indicating that the system can maintain stable operation under weaker coupling conditions and the effective transmission range can be extended.

[0064] In addition, increase While expanding the strong coupling region, it can also directly improve the output power level of the system. Through the derivation of equation (7), it can be obtained that when... At that time, the load power has a maximum value. Due to the limitations of the UAV's airframe structure, this application mainly considers... In this situation, hour, The larger the value, the greater the power received by the load. Load power and The trend relationship is as follows Figure 4 As shown.

[0065] This application clarifies through theoretical derivation that increasing the equivalent inductance of the receiver is the key to reducing... This provides a direct and effective way to improve the system's output power level within the PT symmetrical operating range, and also enhances the system's output power level. Based on this, this application provides a receiving coil module. .

[0066] like Figure 2 As shown, the receiving coil module Including a first receiving coil connected in series Second receiving coil and the third receiving coil ;

[0067] First receiving coil Second receiving coil and the third receiving coil Both are planar helical coils, and the second receiving coil L s2 Installed on the bottom of the drone fuselage; the first receiving coil and the third receiving coil The components are respectively mounted on two mounting plates, which are rotatably mounted on the landing gears on both sides of the UAV. The landing gears are equipped with drive modules for driving the mounting plates to rotate.

[0068] In this embodiment, the drone's landing gear is a U-shaped bracket. A mounting plate is embedded within the U-shaped bracket. Rotating shafts are located on both sides of the mounting plate, rotatably mounted on two columns of the U-shaped bracket. One rotating shaft extends from one column of the U-shaped bracket and connects to a drive module. In this embodiment, the drive module is a stepper motor. After the drone lands, the first receiving coil can be adjusted by detecting the load power of the receiving end. and the third receiving coil With the second receiving coil The angle between them allows the system to operate in the PT symmetric region.

[0069] In this embodiment, during the adjustment process, the first receiving coil and the third receiving coil With the second receiving coil The included angles between them all satisfy the condition that they are greater than 90° and less than or equal to 180°.

[0070] In this embodiment, the distributed receiving coil module can extend the effective magnetic flux capture area and enhance the coupling between coils, and its magnetic field lines are distributed as follows: Figure 5 As shown in (b). The magnetic field line distribution is compared to that of a conventional single-receiving coil structure. Figure 5 (a) As can be seen from the comparison, the effective magnetic flux capture area formed by this application is larger, and its coupling ability in the spatial dimension is stronger.

[0071] In this embodiment, the equivalent circuit diagram of the receiving coil module is as follows: Figure 6 As shown, Figure 6 middle: , and These are the self-inductances of the series-connected coils. , and These refer to the mutual inductance between the coils. The total self-inductance is due to multiple coils connected in series. The precise expression is:

[0072] (9)

[0073] It expands the effective flux trapping area and its mutual inductance with the transmitting coil. The attenuation is slower when offset occurs, further ensuring performance in practical applications. The conditions are easier to meet.

[0074] Example 2:

[0075] This application also provides a parameter design method for an anti-offset UAV wireless charging system based on PT symmetry, applied to the anti-offset UAV wireless charging system based on PT symmetry described in Example 1. The specific steps are as follows:

[0076] S1: Determine the parameters of the transmitting coil and the first, second and third receiving coils, as well as the DC power supply output voltage, based on the UAV's load and power transmission level parameters and installation dimensions;

[0077] In this embodiment, the parameters of the transmitting coil and the first, second and third receiving coils are simulated in Maxwell simulation software. The coil parameters include the coil side length, the number of coil turns, the inter-turn distance and the wire diameter of the winding.

[0078] S2: Based on the coil parameters and output voltage parameters obtained in step S1, determine the compensation capacitor values ​​in the primary and secondary compensation circuits using simulation tools;

[0079] S3: Collect the load power of the system operating in the PT symmetrical region at multiple angles using the first and third receiving coils;

[0080] In this embodiment, simulation software is used to simulate the load power of the system operating in the PT symmetrical region when the transmitting coil and the second receiving coil are directly opposite each other, and the first receiving coil and the third receiving coil are at multiple angles, and the simulation power is used to create a lookupable load power table.

[0081] S4: After the drone lands, the receiver load power is collected. Based on the load power, it is determined whether the system is operating in the PT symmetry region. If so, the drone load is charged. If not, the angle of the first receiving coil and / or the third receiving coil is adjusted to make the system operate in the PT symmetry region.

[0082] In this embodiment, initially, the first and third receiving coils are tilted at the same angle to the UAV landing gear (the angle between them and the end face of the second receiving coil is greater than 90° and less than 180°). When the UAV needs to charge and land, there will be a certain offset between the receiving end and the transmitting end. Therefore, by collecting the load power of the receiving end, it is determined whether it meets the load power table of the steps. If it does, it means that the current offset system can work in the PT symmetry region. Otherwise, it means that the current position cannot work in the PT symmetry region, and the first and third receiving coils need to be adjusted so that the system works in the PT symmetry region. During the adjustment, a single step-by-step method is used (increasing the angle of one receiving coil by one unit). The load power is collected and judged once after each angle adjustment.

[0083] S5: Simulation Verification:

[0084] S5.1: System parameters and PT symmetric region analysis:

[0085] To verify the performance improvement of the proposed PT-symmetric WPT system based on a distributed multi-coil receiver compared to traditional structures, this application establishes two simulation models for comparative analysis: a traditional single-coil system and the multi-coil system of this application. All simulation parameters are set based on typical application scenarios of UAV wireless charging (such as transmission distance and coil size constraints), and the parameters are kept consistent at both the transmitter and receiver unit levels to fairly reflect the impact of structural differences.

[0086] In the Maxwell simulation software, a magnetic circuit simulation model is built. The Maxwell model parameters are shown in Table 1. The three receiving coils of the multi-coil receiver are designed exactly the same, with equal self-inductance values, and are connected in series.

[0087] Table 1 Maxwell model parameters

[0088]

[0089] Based on the parameters obtained from the simulation model, a circuit simulation model was built in Simulink. The circuit parameters are shown in Table 2.

[0090] Table 2 Circuit Simulation Parameters

[0091]

[0092] Combining equation (6) and the current circuit parameters, the critical coupling coefficient of the single-coil system at this point is... Critical coupling coefficient of multi-coil systems The multi-coil system is 63% lower than the WPT system based on the single-coil PT.

[0093] The coupling coefficients of the two receiver structures vary with transmission distance as shown in the curves. Figure 7 As shown, Figure 7 (a) is a single-coil structure. Figure 7 (b) shows a multi-coil structure. As can be seen from the figure, the coupling coefficient of the multi-coil structure is significantly higher than that of the single-coil structure at the same transmission distance, which is due to its extended flux trapping region. In addition, the comparative results show that the coupling coefficient of the multi-coil system is still higher than its critical value at a greater distance, proving the extension of its PT-symmetric operating region.

[0094] S4.2: Verification of energy efficiency characteristics and anti-deflection performance:

[0095] Based on the circuit parameters shown in Table 2, a simulation model was built in Simulink. The system operating frequency was given according to the coupling coefficient, and the output power and transmission efficiency of the system were obtained.

[0096] Figure 8 a and Figure 8 b shows the output power and transmission efficiency of the two systems in the PT symmetry region. Figure 8 (a) is a single-coil structure. Figure 8 (b) shows a multi-coil structure. Simulation results indicate that within the PT symmetry region, the output power and transmission efficiency of both single-coil and multi-coil systems remain essentially constant, which aligns with the predictions of PT symmetry theory. Furthermore, within the PT symmetry region, the multi-coil system maintains a higher constant power level than the single-coil system. This is attributed to the increased equivalent inductance at the receiver, demonstrating the advantage of distributed receiving coil modules in enhancing transmission power.

[0097] In summary, this application expands the effective magnetic flux capture area by setting three series-connected receiving coils, thereby reducing the PT symmetry threshold and expanding the stable operating region. When offset occurs, the system can maintain constant transmission efficiency and power, while effectively improving the system's output power level, thus achieving comprehensive optimization of system transmission performance and robustness.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A PT-symmetry based anti-drift unmanned aerial vehicle wireless charging system, comprising a transmitting end and a receiving end, characterized in that, The receiving end comprises a receiving coil module, which comprises a first receiving coil, a second receiving coil and a third receiving coil connected in series. The first, second and third receiving coils are all planar coils, and the included angles between the first and third receiving coils and the second receiving coil are adjustable, and the included angles between the first and third receiving coils and the second receiving coil all satisfy: greater than 90° and less than or equal to 180°.

2. The PT-symmetry based anti-shift drone wireless charging system of claim 1, wherein, The transmitting end comprises a direct current power supply, a high-frequency inverter, a primary side compensation circuit and a transmitting coil connected in series, and a control circuit arranged between the output end and the control end of the high-frequency inverter; The control circuit comprises a current sampling module, a zero-crossing comparison module and a driving module, the current sampling module is used for collecting the current of the output end of the high-frequency inverter and transmitting it to the zero-crossing comparison module, the zero-crossing comparison module is used for determining a zero-crossing signal according to the current signal and feeding it back to the driving module, and the driving module is used for generating a corresponding driving signal to control the switching tube of the high-frequency inverter in real time.

3. The PT-symmetry based anti-shift drone wireless charging system of claim 1, wherein, The second receiving coil is arranged at the bottom of the unmanned aerial vehicle body. The first and third receiving coils are arranged on two mounting plates, respectively, and the two mounting plates are rotatably mounted on the landing gears on the two sides of the unmanned aerial vehicle, and the landing gears are provided with driving modules for driving the mounting plates to rotate.

4. The PT-symmetry based anti-shift drone wireless charging system of claim 2, wherein, The receiving end further comprises a secondary side compensation circuit and an unmanned aerial vehicle load connected in series, and the input end of the secondary side compensation circuit is connected with the receiving coil module.

5. The PT-symmetry based anti-shift drone wireless charging system of claim 2, wherein, The high-frequency inverter is a single-phase full-bridge inverter.

6. The PT-symmetry based anti-shift drone wireless charging system of claim 4, wherein, The primary side compensation circuit and the secondary side compensation circuit are SS topology structures.

7. The PT-symmetry based anti-shift drone wireless charging system of claim 6, wherein, The self-inductance of the receiving coil module is: L s = L s1 + L s2 +L s3 +2(M 12 +M 13 + M 23 ), L s1 , L s2 and L s3 are the self-inductances of the first, second and third receiving coils, respectively, and M 12 , M 13 and M 23 are the mutual inductances between the three receiving coils.

8. The PT-symmetry based anti-shift drone wireless charging system of claim 7, wherein, The system satisfies: coupling coefficient k is greater than or equal to critical coupling coefficient k c , the critical coupling coefficient , in the formula: R s is the equivalent load of the receiving end, C s is the secondary side compensation capacitance value in the secondary side compensation circuit.

9. A parameter design method of a PT-symmetry-based anti-offset unmanned aerial vehicle wireless charging system, characterized in that, The method is applied to the PT symmetry-based anti-offset unmanned aerial vehicle wireless charging system according to any one of claims 1-8, and the specific steps are as follows: S1: determining the parameters of the transmitting coil, the first, second and third receiving coils and the output voltage of the direct current power supply according to the unmanned aerial vehicle load and power transmission level parameters and installation size; S2: determining the compensation capacitance values in the primary side and secondary side compensation circuits through a simulation tool according to the coil parameters and output voltage parameters obtained in step S1; S3: collecting the load power when the system works in the PT symmetry region at multiple angles of the first and third receiving coils; S4: after the unmanned aerial vehicle lands, collecting the load power of the receiving end, determining whether the system works in the PT symmetry region according to the load power, if yes, charging the unmanned aerial vehicle load, and if no, adjusting the angle of the first receiving coil or / and the third receiving coil to make the system work in the PT symmetry region.

10. The parameter design method of a PT-symmetry-based anti-shift unmanned aerial vehicle wireless charging system according to claim 9, wherein The system works in PT symmetric region of the load power P L For: , where: R p and R s are the transmitting end load and receiving end load, L p and L S are the transmitting coil self-inductance and receiving coil module self-inductance, U AB is the transmitting end output voltage.

Images