Offshore wind power maintenance unmanned aerial vehicle relay charging structure

Abstract

This invention provides a relay charging structure for offshore wind power maintenance drones, belonging to the field of drone charging technology. Addressing the problems of high positioning accuracy requirements, complex mechanical structures, high maintenance difficulty, susceptibility to corrosion, and poor reliability in existing offshore wind power maintenance drone charging technologies, this invention employs wireless power transmission technology to provide a charging method that eliminates physical contact. The structure includes a wireless power transmitting module and a wireless power receiving module. The wireless power transmitting module includes a transmitting coil, a transmitting-end compensation circuit, an AC / DC rectifier, a Buck converter, and a DC / AC inverter; the wireless power receiving module includes a receiving coil, a receiving-end compensation circuit, an AC / DC rectifier, and a Buck converter. The transmitting coil adopts a bipolar "U"-shaped three-coil structure, and the receiving coil adopts a dual-plane polarization structure, forming an LCL-S type compensation circuit to achieve constant voltage and constant current energy exchange. This invention transmits energy through electromagnetic fields, eliminating the need for plug-and-play interfaces and mechanical contacts, effectively solving the charging stability problem in complex offshore environments, significantly improving the operational efficiency and reliability of drones, while reducing maintenance frequency and failure rate.

Description

Technical Field

[0001] This invention relates to the field of drone charging technology, and in particular to a relay charging structure for offshore wind power maintenance drones. Background Technology

[0002] As the global energy structure shifts towards low-carbon and green development, offshore wind power, as a form of clean and renewable energy, has experienced rapid growth in recent years. However, due to the complex environment and distance from land, offshore wind farms face challenges such as high costs, high risks, and low efficiency in their operation and maintenance. Traditional manual inspection and maintenance methods are limited by weather, sea conditions, and other factors, making it difficult to meet the demands for efficient operation and maintenance. Therefore, utilizing drones for wind turbine blade inspection, fault identification, and auxiliary maintenance has become an industry trend.

[0003] However, limited by battery life, most drones used for wind power operation and maintenance have limited flight time per flight, making it difficult to fully cover the wind farm area, severely impacting operational efficiency and application scope. To address this issue, deploying relay charging platforms or base stations within wind farms is a common industry solution to indirectly expand the coverage area for drone missions. While these solutions extend the drone's operating radius to some extent, they still have many shortcomings, such as stringent positioning accuracy requirements, complex mechanical structures, and high maintenance difficulty. Especially in harsh marine environments, existing charging structures are susceptible to corrosion, vibration, and impact, leading to decreased system reliability and making it difficult to guarantee the drone's long-term, high-frequency autonomous operation needs. For example, Chinese patent document CN222876302U describes a drone relay charging platform and drone, detailing the electrical connection between conductive components and a power distribution mechanism. The problem with this drone recharging solution is that, under marine conditions, the conductive components are prone to short circuits, posing a risk. Therefore, it is necessary to develop a drone relay charging structure that is suitable for complex marine environments, has efficient energy transmission capabilities, and good environmental adaptability, which can significantly improve the operational capabilities and practicality of offshore wind power maintenance drones. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a relay charging structure for offshore wind power maintenance drones, solving the problems of high positioning accuracy requirements, complex mechanical structures, high maintenance difficulty, susceptibility to corrosion, and poor reliability in existing technologies. To achieve the above objectives, the present invention provides the following solution: Includes a wireless power transmission module and a wireless power receiving module. The wireless power transmission module includes a transmitting coil, a transmitting end compensation circuit, an AC / DC rectifier, a Buck converter, and a DC / AC inverter. The wireless power receiving module includes a receiving coil, a receiving end compensation circuit, an AC / DC rectifier, and a Buck converter.

[0005] The input of the wireless power transmitting module is directly connected to an AC power source; the output of the wireless power receiving module is directly connected to the drone battery or charging port for charging, and energy is transferred between the modules through electromagnetic fields.

[0006] The transmitting coil in the wireless power transmitting module adopts a bipolar "U"-shaped three-coil structure; the receiving coil in the wireless power receiving module adopts a dual-plane polarization structure. The coils work together to enhance anti-offset capability, improve magnetic coupling rate, and reduce transmission loss.

[0007] The transmitter compensation circuit in the wireless power transmission module adopts an LCL-type topology design; the receiver compensation circuit in the wireless power receiving module adopts an S-type topology design, forming an LCL-S-type compensation circuit to realize constant voltage and constant current energy exchange between the transmitter and receiver.

[0008] The AC / DC rectifier in the wireless power transmission module uses a diode rectifier bridge to convert the AC input voltage into DC power.

[0009] The DC / AC inverter in the wireless power transmission module consists of a switching transistor array containing four switching transistors. The switching frequency of the switching transistors is controlled by an external chip to achieve dynamic adjustment of the output voltage frequency.

[0010] The AC / DC rectifier in the wireless power receiver module uses a full-bridge switching transistor array for rectification. The driver IC dynamically controls the switching frequency of the transistors based on the input and output voltages to reduce ripple and maintain a stable output voltage.

[0011] Both the wireless power transmitting and receiving modules employ Buck converters with a Buck topology design. A main control chip is introduced to process the converter switching frequency, thereby adjusting the output voltage as needed and implementing overvoltage and overcurrent protection to ensure circuit safety.

[0012] The wireless power transmission module consists of a rectangular flat coil plate and a block-shaped integrated circuit module. The block-shaped integrated circuit module is assembled on the back of the coil plate, with the transmitting surface of the coil plate facing vertically upward. The integrated circuit module is embedded vertically downward on a drone landing platform made of non-magnetic material, or placed directly on the surface of the platform or support.

[0013] The wireless power receiving module consists of a rectangular flat coil plate and a block-shaped integrated circuit module. The block-shaped integrated circuit module is assembled on the back of the coil plate, with the receiving surface of the coil plate facing vertically downwards. The integrated circuit module is suspended or fixedly installed on the bottom of the UAV with its vertical orientation upwards.

[0014] The external structures of the wireless power transmitter module and the wireless power receiver module can be adapted and adjusted by adjusting the size of the coil board according to the required transmission power, positioning range, and drone payload, so as to achieve one-to-N, multiple drones charging simultaneously.

[0015] The present invention provides a relay charging structure for offshore wind power maintenance drones, which has the following beneficial effects: This invention employs a wireless power system, enabling energy transfer without physical contact, eliminating the need for plug-and-play interfaces and mechanical contacts required in traditional charging methods. This ensures stable and safe charging even in complex marine environments, especially under rough seas, effectively reducing mechanical wear caused by long-term use and significantly lowering maintenance frequency and failure rate. Furthermore, the system supports more flexible charging location matching capabilities, achieving efficient energy coupling and stable charging regardless of changes in the drone's landing attitude or model differences. Furthermore, the complex structures such as drone cellular networks and connectors required by traditional charging platforms have been eliminated, enabling the landing platform to be designed with integration in mind, thus reducing manufacturing and deployment costs. The entire charging process is highly automated, from the drone landing and alignment to the start of energy transfer, all of which can be completed autonomously, greatly improving the system's intelligence and operational efficiency and reducing reliance on manual operation. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a circuit schematic diagram of the wireless power transmission module of the present invention.

[0017] Figure 2 This is a circuit schematic diagram of the wireless power receiving module of the present invention.

[0018] Figure 3 This is a schematic diagram of the transmitting coil structure of the present invention.

[0019] Figure 4 This is a schematic diagram of the receiving coil structure of the present invention.

[0020] Figure 5 This is a schematic diagram of the wireless power transmitting and receiving module of the present invention.

[0021] Figure 6 This is a diagram illustrating the charging status of the drone.

[0022] In the diagram: Rectifier bridge D DC Input capacitor C1, switching transistor Q1, freewheeling diode D1, power inductor L1, voltage regulator capacitor C2, switching transistor array (transistors Q2, Q3, Q4, Q5), primary compensation inductor L2, primary compensation capacitor C3, primary coil self-inductance Lp Secondary coil self-inductance L s Secondary compensation capacitor C4, ideal diode controller U1, rectifier switch array switches Q6, Q7, Q8, Q9, secondary input capacitor C6, secondary switch Q 10 Secondary freewheeling diode D3, secondary power inductor L4, output voltage regulator capacitor C5, transmitting first coil 1, transmitting second coil 2, transmitting third coil 3, iron oxide strip group 4, receiving first coil 5, receiving second coil 6, receiving module 100, transmitting module 200, drone 300, charging platform 400. Detailed Implementation

[0023] Preferred embodiments of the present invention will be described below with reference to the accompanying drawings: The circuit diagram of the wireless power transmission module 200 is as follows: Figure 1 As shown, it includes a rectifier bridge Ddc, a Buck converter, a set of switching transistor arrays and an LCL compensation circuit.

[0024] The rectifier bridge uses the KBPC5010 model, with a maximum reverse peak voltage of up to 1000V, a maximum average forward current of up to 50A, a forward voltage drop of only 1.0–1.2V, and an operating temperature range of -55°C to 150°C. It is used to directly rectify 220V 50Hz AC mains power and provide reliable DC power.

[0025] The Buck converter is connected to the rectifier bridge D. dc The output DC bus and ground line include the input capacitor C1, switching transistor Q1, freewheeling diode D1, power inductor L1, and Zener capacitor C2. Input capacitor C1 is connected in parallel to the rectifier bridge Ddc, with its anode connected to the drain of switching transistor Q1 and its cathode connected to the common ground. The source of switching transistor Q1 is connected to the anode of freewheeling diode D1 and one end of power inductor L1, while the other end of power inductor L1 is connected to the anode of Zener capacitor C2. The cathodes of diode D1 and Zener capacitor C2 are both connected to the common ground.

[0026] The array of switches, consisting of four transistors Q2, Q3, Q4, and Q5, is connected in parallel to the Buck converter. The drains of transistors Q2 and Q3 are connected to the anode of the Zener capacitor C2, and their sources are connected to the drains of transistors Q4 and Q5, respectively. The sources of transistors Q4 and Q5 are connected to a common ground.

[0027] The LCL compensation circuit is connected to the source of Q2 and Q3 in the switching transistor array, and includes a primary compensation inductor L2, a primary compensation capacitor C3, and a primary coil self-inductance Lp. The compensation capacitor C3 and the coil self-inductance Lp are connected in parallel and in series with the compensation inductor L2.

[0028] When the wireless power transmission module 200 is working, if a 220V-50Hz mains power supply is connected, it will output a DC power supply after rectification by the rectifier bridge Ddc. The DC voltage will fluctuate around 310V, depending on the load.

[0029] The DC current is stepped down by a Buck converter. The output voltage of the Buck converter is controlled by the switching transistor Q1, and its output voltage equals the input voltage. Duty cycle: When the switch Q1 is closed, the current path is rectifier bridge Ddc - switch Q1 - power inductor L1; when the switch Q1 is open, the current path is power inductor L1 - switch array - freewheeling diode D1.

[0030] The switching array consists of two groups: Q2 and Q5, and Q3 and Q4. Each group is turned on at intervals, meaning they are not turned on simultaneously, in order to generate high-frequency signals for energy transmission.

[0031] Preferred, such as Figure 3 As shown, the transmitting coil in the wireless power transmitting module 200 adopts a bipolar "U"-shaped three-coil structure, which consists of two rectangular bipolar coils that are spatially perpendicular to each other and electrically have a phase difference of 90 degrees. This generates a rotating magnetic field, thereby enabling efficient and stable energy transmission to receiving devices placed in any direction. This is suitable for wireless charging systems that require support for the free placement of receiving devices. In this embodiment, the coils are specifically arranged as follows: Figure 3 As shown: The first transmitting coil 1 and the third transmitting coil 3 are placed side by side horizontally on the iron oxide strip group 4. The radial direction of the iron oxide strip group 4 is consistent with the arrangement direction of the coil group composed of the first transmitting coil 1 and the third transmitting coil 3. The third transmitting coil 3 is stacked on the coil group composed of the first transmitting coil 1 and the third transmitting coil 3, and its central symmetry line coincides vertically with the joint of the coil group. The wire is input from the pin of the first transmitting coil 1, connected to the third transmitting coil 3 in reverse, and output from the pin of the second transmitting coil 2 to generate a uniform rotating magnetic field.

[0032] The LCL-s compensation topology provides a load-independent constant current and constant voltage output. Its equivalent current Ip depends only on the output voltage of the switching array, the compensation inductor L2, and the coil self-inductance Lp, as expressed in the following expression: Where ω0 is the resonant frequency, and its expression is:

[0033] The induced voltage of the wireless power transmitter module 200 during operation should be between 90~96V and 80KHz~120Khz.

[0034] When selecting components for the line power transmitter module 200 and the wireless power receiver module 100, the following should be noted: the reverse withstand voltage of the switching transistor Q1 should be higher than 400V to prevent breakdown, and its on-resistance and parasitic capacitance should be as small as possible to reduce losses; the reverse withstand voltage of the freewheeling diode D1 should be higher than 100V to prevent breakdown, and its on-resistance should be as small as possible to reduce losses; the switching transistors in the switching transistor array should have short switching times, low on-resistance, and withstand voltages higher than the output voltage; the resistors and capacitors should be adjusted according to the output power to ensure continuous operation and make the system controllable.

[0035] The circuit diagram of the wireless power receiving module 100 is as follows: Figure 2 As shown, it includes an S-compensation network, a switching rectifier bridge, and a Buck converter.

[0036] Preferred, such as Figure 4 As shown, the receiving coil in the wireless power receiving module 100 adopts a dual-plane polarization structure, which is a coil structure used to improve the charging efficiency of the receiving end under misalignment and tilt conditions. Unlike the traditional single-layer planar coil, the dual-plane polarization structure receiving coil is composed of two or more coil units wound on different physical planes, which can generate multi-directional magnetic field components, making its magnetic field distribution more "three-dimensional", and has the characteristics of high power conversion efficiency, small size and light weight. In this embodiment, the receiving coils are specifically arranged as follows: Figure 4 As shown: The receiving first coil 5 and the receiving second coil 6 are placed side by side horizontally on the iron oxide strip group 4. The radial direction of the iron oxide strip group 4 is consistent with the arrangement direction of the coil group composed of the receiving first coil 5 and the transmitting receiving second coil 6. The wire is input from the pin of the receiving first coil 5 and output from the pin of the receiving second coil 6 to generate a uniform semi-circular three-dimensional magnetic field.

[0037] The S-compensation network works in conjunction with the LCL compensation topology at the transmitting end to form a constant current and constant voltage output unrelated to the load. The impedance of the series secondary compensation capacitor C4 should be equal to the self-inductance Ls of the secondary coil.

[0038] The switching rectifier bridge includes an ideal diode controller U1 (LT4320) and four rectifier switches Q6, Q7, Q8, and Q9. Switches Q6 and Q8 have their drains as anodes (output) and are connected to the OUTP interface of U1, controlled by TG1 and TG2 respectively. Switches Q7 and Q9 have their sources as cathodes (output) and are connected to the OUTN interface of U1, controlled by BG1 and BG2 respectively. The maximum output voltage is 72V.

[0039] The Buck converter works on the same principle as the transmitter, and is used to adjust the charging voltage of different batteries, so it will not be described again.

[0040] When the wireless power receiving module 100 is working, the coil receives the induced voltage. After compensation by the compensation circuit, the AC induced voltage is rectified into DC voltage by the switching transistor rectifier bridge. The DC voltage is then stepped down by the Buck converter and output to the load.

[0041] The output control method of the Buck converter on both the transmitting and receiving ends is to monitor the output voltage and output current, output the signal to the external control chip UC3843, and perform PID adjustment on the switching frequency to prevent overvoltage and overcurrent.

[0042] Among them, the bipolar "U"-shaped three-coil structure combined with the dual-plane polarization structure has stronger anti-offset capability, and provides a greater degree of coil matching error under the premise of slightly reducing transmission efficiency. The coil is made of multiple strands of Litz wire wound into a double-layer orthogonal coil. The orthogonal arrangement of the transmitting and receiving coils reduces the efficiency drop caused by the offset at the receiving end and maximizes the transmission efficiency. At the same time, a high permeability toroidal manganese-zinc ferrite core is used to reduce leakage flux and improve coupling efficiency. The operating frequency should cover 80KHz~120KHz.

[0043] Preferably, the Buck converter uses the main control chip UC3843 to generate PWM signals, dynamically controls the MOSFET switches according to the load voltage and load, adjusts the duty cycle, and maintains constant voltage and constant current at the output / receive end.

[0044] Preferably, a combination of high-voltage solid aluminum electrolytic capacitors and ceramic capacitors is used to control high-voltage and high-frequency noise at the input and output terminals, thereby reducing ripple.

[0045] Preferably, the wireless power transmission module 200 has a rectangular flat plate structure, the size of which can be adjusted according to the required power. It is connected to an external power source through a common two-prong plug and can be fixedly installed on the surface of any non-magnetic landing platform or embedded inside the landing platform as a charging platform 400, such as a stainless steel landing platform or a cement landing platform.

[0046] Preferably, the wireless power receiving module 100 has a rectangular flat structure, the size of which can be adjusted according to the required power. It is connected to the power supply unit of the UAV 300 through a common two-prong plug, and can be fixed to the bottom of the UAV 300 by straps or screws, replacing the landing bracket.

[0047] Preferably, the housing of the receiver module 100 and the transmitter module 200 is made of magnesium-aluminum alloy to reduce electromagnetic interference, reduce weight, and enhance heat dissipation.

[0048] Preferably, the housing cavities of the receiving module 100 and the transmitting module 200 are filled with highly thermally conductive and corrosion-resistant heat-dissipating silicone to enhance heat dissipation and protect the internal metal circuits from sea salt spray corrosion.

[0049] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The embodiments and features described in these embodiments can be arbitrarily combined without conflict. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A relay charging structure for offshore wind power maintenance drones, characterized in that: Includes a wireless power transmitting module and a wireless power receiving module; The wireless power transmission module includes a transmitting coil, a transmitting end compensation circuit, an AC / DC rectifier, a Buck converter, and a DC / AC inverter. The wireless power receiving module includes a receiving coil, a receiving end compensation circuit, an AC / DC rectifier, and a Buck converter.

2. The relay charging structure for offshore wind power maintenance drones according to claim 1, characterized in that: The input terminal of the wireless power transmission module is directly connected to an AC power supply; The output of the wireless power receiver module can be directly connected to the drone's battery or charging port for charging. Energy is transferred between modules via electromagnetic fields.

3. The relay charging structure for offshore wind power maintenance drones according to claim 1, characterized in that: The transmitting coil in the wireless power transmitting module adopts a bipolar "U"-shaped three-coil structure; the receiving coil in the wireless power receiving module adopts a dual-plane polarization structure. The coils work together to enhance anti-offset capability, improve magnetic coupling rate, and reduce transmission loss.

4. The relay charging structure for offshore wind power maintenance drones according to claim 1, characterized in that: The transmitter compensation circuit in the wireless power transmission module adopts an LCL-type topology design; the receiver compensation circuit in the wireless power receiving module adopts an S-type topology design, forming an LCL-S-type compensation circuit to realize constant voltage and constant current energy exchange between the transmitter and receiver.

5. The relay charging structure for offshore wind power maintenance drone according to claim 1, characterized in that: The AC / DC rectifier in the wireless power transmission module uses a diode rectifier bridge to convert the AC input voltage into DC power.

6. The relay charging structure for offshore wind power maintenance drone according to claim 1, characterized in that: The DC / AC inverter in the wireless power transmission module consists of a switching transistor array containing four switching transistors. The switching frequency of the switching transistors is controlled by an external chip to achieve dynamic adjustment of the output voltage frequency.

7. The relay charging structure for offshore wind power maintenance drone according to claim 1, characterized in that: The AC / DC rectifier in the wireless power receiver module uses a full-bridge switching transistor array for rectification. The driver IC dynamically controls the switching frequency of the transistors based on the input and output voltages to reduce ripple and maintain a stable output voltage.

8. The relay charging structure for offshore wind power maintenance drone according to claim 1, characterized in that: Both the wireless power transmitting and receiving modules employ Buck converters with a Buck topology design. A main control chip is introduced to process the converter switching frequency, thereby adjusting the output voltage as needed and implementing overvoltage and overcurrent protection to ensure circuit safety.

9. The relay charging structure for offshore wind power maintenance drones according to claim 1, characterized in that: The wireless power transmission module consists of a rectangular flat coil plate and a block-shaped integrated circuit module. The block-shaped integrated circuit module is combined on the back of the coil plate. The transmitting surface of the coil plate faces vertically upward, and the integrated circuit module is embedded vertically downward in a UAV landing platform made of non-magnetic material, or placed directly on the surface of the platform or support. The wireless power receiving module consists of a rectangular flat coil plate and a block-shaped integrated circuit module. The block-shaped integrated circuit module is assembled on the back of the coil plate, with the receiving surface of the coil plate facing vertically downwards. The integrated circuit module is suspended or fixedly installed on the bottom of the UAV with its vertical orientation upwards.

10. The relay charging structure for offshore wind power maintenance drone according to claim 1, characterized in that: The external structure of the wireless power transmitting module and the wireless power receiving module can be adjusted by changing the size of the coil plate according to the required transmission power, positioning range and UAV payload.

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