Flow medium-based capacitive wireless power transmission coupling structure and regulation method

Abstract

The application discloses a kind of based on flowing medium's capacitive wireless power transmission coupling structure and regulation and control method.The structure includes: the first plate and the second plate of transmitting side;Third plate and fourth plate of receiving side;Wherein, the first plate and the third plate are all arranged in air medium above water surface, the first plate and the third plate are oppositely arranged, form overwater main coupling area;The second plate and the fourth plate are all arranged in conductive medium below water surface, the second plate and the fourth plate are oppositely arranged, form underwater main coupling area;Flowing medium supply component is used to introduce flowing medium to the opposite gap between the first plate and the third plate, so that the first plate and the third plate form continuous flowing medium area across the opposite gap.The application can increase overwater main coupling capacitance value, improve power transmission capacity.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and in particular to a capacitive wireless power transmission coupling structure and control method based on a flowing medium, applicable to wireless charging scenarios for ships, port equipment, floating platforms, offshore floating devices, and other equipment in water or near-water environments. Background Technology

[0002] Wireless power transfer technology, due to its characteristics of having no mechanical plug-in contacts, facilitating automated docking, and reducing the risk of contact corrosion and leakage, has broad application prospects in electric vehicles, electric ships, underwater equipment, and shore power systems in ports. Based on different energy coupling mechanisms, wireless power transfer technologies mainly include inductive wireless power transfer and capacitive wireless power transfer. Inductive wireless power transfer typically relies on coils, magnetic cores, and magnetic shielding structures to achieve magnetic field coupling, resulting in higher requirements for system weight, cost, and mechanical support. Capacitive wireless power transfer transfers energy through a high-frequency electric field between plates. Its coupler mainly consists of metal plates and an insulating structure, offering advantages such as simple structure, light weight, low cost, easy waterproof sealing, and insensitivity to metallic foreign objects.

[0003] Traditional capacitive wireless power transfer systems typically use air as the transmission medium. However, air has a relatively low permittivity, resulting in a small main coupling capacitance between the plates. When the system needs to achieve higher power transfer, it is often necessary to increase the plate area, increase the plate voltage, or use a complex compensation network. This increases the size of the coupling structure, makes electric field safety design more difficult, and limits its application in high-power scenarios such as wireless charging for ships.

[0004] The relative permittivity of water is 81 times that of air, which is beneficial for increasing the coupling capacitance between the plates and the system power density. However, water exhibits significant conductivity. When all four plates of a capacitive wireless power transfer coupler are submerged in water, the water environment may create conductive paths between plates on the same side or between unpaired plates. This can lead to self-coupling, cross-coupling, or short-circuit-like effects, resulting in significant reactive circulating current and conductive losses, thus reducing the efficiency of energy transfer from the transmitting side to the receiving side. Summary of the Invention

[0005] To address the issues of small main coupling capacitance and low power density in existing cross-medium capacitive wireless power transfer structures, this invention provides a capacitive wireless power transfer coupling structure and method based on the spatial distribution control of the flowing medium.

[0006] To achieve the above objectives, according to one aspect of the present invention, a capacitive wireless power transfer coupling structure based on a flowing medium is provided, comprising: The transmitter-side conductor unit includes a first electrode plate and a second electrode plate; The receiving-side conductor unit includes a third electrode plate and a fourth electrode plate; The first electrode plate and the third electrode plate are both disposed in the air medium above the water surface, and the first electrode plate and the third electrode plate are arranged opposite to each other to form the main coupling region above the water. Both the second electrode plate and the fourth electrode plate are disposed in a conductive medium below the water surface. The second electrode plate and the fourth electrode plate are arranged opposite to each other to form an underwater main coupling region. A flow medium supply assembly is used to introduce a flow medium into the opposing gap between the first electrode plate and the third electrode plate, such that a continuous flow medium region spanning the opposing gap is formed between the first electrode plate and the third electrode plate, wherein the dielectric constant of the flow medium is greater than that of air.

[0007] Furthermore, the surfaces of the first electrode plate, the third electrode plate, the second electrode plate, and the fourth electrode plate are all covered with an insulating layer.

[0008] Furthermore, the distance between the first electrode plate and the third electrode plate is... d a The maximum thickness of the continuous flow medium region along the main electric field direction is: h f ,satisfy .

[0009] Furthermore, the flowing medium supply assembly includes a water pump, a water supply pipe, a water outlet, and an insulating return water tank. The water pump, water supply pipe, and water outlet introduce the flowing medium into the opposing gap between the first electrode plate and the third electrode plate. The insulating return water tank is used to receive the flowing medium flowing out between the first electrode plate and the third electrode plate.

[0010] Furthermore, the insulating return water tank is provided with multiple dispersed return water holes.

[0011] Furthermore, the average drainage rate of the insulating return water tank per unit time is not less than the average supply rate of the flowing medium supply component per unit time.

[0012] Furthermore, the conductive medium is the same material as the flowing medium.

[0013] Furthermore, the transmitting-side conductor unit is mounted on the shore-side robotic arm, and the receiving-side conductor unit is mounted on the ship-side robotic arm.

[0014] According to another aspect of the present invention, the present invention provides a method for controlling a capacitive wireless power transfer coupling structure based on a flowing medium, the capacitive wireless power transfer coupling structure comprising: The transmitter-side conductor unit includes a first electrode plate and a second electrode plate; The receiving-side conductor unit includes a third electrode plate and a fourth electrode plate; The first electrode plate and the third electrode plate are both disposed in the air medium above the water surface, and the first electrode plate and the third electrode plate are arranged opposite to each other to form the main coupling region above the water. Both the second electrode plate and the fourth electrode plate are disposed in a conductive medium below the water surface. The second electrode plate and the fourth electrode plate are arranged opposite to each other to form an underwater main coupling region. A flow medium supply assembly is used to introduce a flow medium into the opposing gap between the first electrode plate and the third electrode plate, such that a continuous flow medium region spanning the opposing gap is formed between the first electrode plate and the third electrode plate, wherein the dielectric constant of the flow medium is greater than that of air. The flowing medium supply assembly includes a water pump, a water supply pipe, a water outlet, and an insulating return water tank. The water pump, water supply pipe, and water outlet introduce the flowing medium into the opposing gap between the first electrode plate and the third electrode plate. The insulating return water tank is used to receive the flowing medium flowing out between the first electrode plate and the third electrode plate. The insulating return water tank is provided with multiple dispersed return water holes. The control method includes the following steps: Obtain the relative distance between the first electrode plate and the third electrode plate. d a ; According to the opposing gap d a The average liquid supply rate Q of the flow medium supply component is determined by considering the widths of the first and third plates, the liquid supply form of the flow medium supply component, the characteristics of the flow medium, and the flow boundary conditions. Based on the water droplet range after the flowing medium is discharged from the opposing gap between the first electrode plate and the third electrode plate, determine the installation position and receiving opening size of the insulating return water tank so that the insulating return water tank covers the water droplet area of ​​the flowing medium. Determine the diameter, number, and arrangement of the return water holes to ensure that the average drainage rate Q per unit time of the insulating return water tank is [value missing]. a satisfy ; The fluid supply assembly is activated, and the fluid is supplied to the gap between the first and third plates according to the average supply volume Q per unit time.

[0015] Compared with the prior art, the capacitive coupler and its flow medium control method provided by the present invention have the following significant advantages: 1. The present invention adopts a cross-medium layout in which the first and third plates are located above the water surface and the second and fourth plates are located below the water surface. It can utilize the difference in medium properties between air and water to suppress the self-coupling problem in the fully underwater quadplate structure. At the same time, the flowing medium is introduced into the opposing gap between the first and third plates, so that the flowing medium forms a continuous flowing medium region across the opposing gap in at least part of the directly opposite area of ​​the first and third plates. This reduces the limitation of the air medium on the coupling capacitance in this region, thereby increasing the main coupling capacitance between P1 and P3.

[0016] 2. This invention adjusts the spatial distribution of the flowing medium within the opposing gap between P1 and P3, allowing the flowing medium to extend along the main electric field direction from the opposing insulating surfaces of P1 to P3 within the corresponding opposing regions. Finite element simulation results show that, under the condition of the same electrode spacing, forming a continuous flowing medium region spanning the opposing gap significantly improves the coupling capacitance between P1 and P3 compared to the state where the flowing medium does not span the opposing gap.

[0017] 3. This invention incorporates an insulating return water tank with return water holes. The return water tank receives the flowing medium exiting between P1 and P3, and the return water holes disperse and return the flowing medium, thereby reducing the likelihood of a stable, continuous conductive fluid forming between the water surface area where P1 and P3 are located and the water area below. The return water holes or return water pipes of the return water tank are designed to match the normal liquid supply state, thereby reducing the continuous accumulation of the flowing medium in the return water tank.

[0018] 4. In this invention, all four electrode plates are covered with an insulating layer, which can prevent the flowing medium from directly conducting with the metal conductive layer, thereby improving the system's corrosion resistance, accidental contact prevention, and operational safety. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall application of the capacitive wireless power transfer coupling structure of the present invention; Figure 2 Maximum flow medium thickness h f A schematic diagram; Figure 3 This is a schematic diagram showing the specific dimensions and relative positions of the coupling structure of the present invention; Figure 4 This is a spatial distribution diagram of the flowing medium across the opposing gaps P1 and P3. Figure 5 This is the equivalent circuit diagram between the four plates of the present invention; Figure 6 This is a schematic diagram of the coupling channel of the capacitive wireless power transmission system of the present invention; Figure 7 This is a circuit topology diagram of the capacitor-type wireless power transfer system of the present invention; Figure 8 This is a flowchart of the flow medium control method of the present invention; Figure 9 The diagram shows the electric field distribution of air across the gap between P1 and P3. Figure 10 The electric field distribution of the water medium across the gap between P1 and P3 is shown. Figure 11 For different spatial distributions of flow media C 13 The curve of change; Figure 12 For different spatial distributions of flow media C 24 The curve of change; Figure 13 For different spatial distributions of flow media C M The curve of change; Explanation of reference numerals in the attached figures: P1: First electrode plate; P2: Second electrode plate; P3: Third electrode plate; P4: Fourth electrode plate; I1: Shore base; I2: Water pump; I3: Water pipe; I4: Return water tank; I5: Ship; I6: Horizontal plane; I7: Water flow; I8: Insulation layer; I9: Aluminum plate; 10 : Water pipe outlet; V in : Transmitter voltage source; V out : Constant voltage load on the receiving side; S 1 、S 2 、S 3 、S 4: Inverter switching transistors for wireless power transmission systems; D 1 、D 2 、D 3 、D 4: Rectifier switching transistors for wireless power transmission systems; L 1 、L 2 、L 3 、L 4: Compensating inductor for wireless power transmission systems; C 1 、C 2: Compensation capacitors for wireless power transmission systems. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] The terms "first," "second," "third," or "fourth," etc., used in the specification, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0023] An embodiment of the present invention provides a capacitive wireless power transfer coupling structure based on a flowing medium, comprising: The transmitter-side conductor unit includes a first electrode plate and a second electrode plate; The receiving-side conductor unit includes a third electrode plate and a fourth electrode plate; The first electrode plate and the third electrode plate are both disposed in the air medium above the water surface, and the first electrode plate and the third electrode plate are arranged opposite to each other to form the main coupling region above the water. Both the second electrode plate and the fourth electrode plate are disposed in a conductive medium below the water surface. The second electrode plate and the fourth electrode plate are arranged opposite to each other to form an underwater main coupling region. A flow medium supply assembly is used to introduce a flow medium into the opposing gap between the first electrode plate and the third electrode plate, such that a continuous flow medium region spanning the opposing gap is formed between the first electrode plate and the third electrode plate, wherein the dielectric constant of the flow medium is greater than that of air.

[0024] In this embodiment of the invention, two electrode plates are placed in the air medium region and two other electrode plates are placed in the water medium region. The difference in medium properties between air and water can be used to suppress the self-coupling problem in the fully underwater quadrupole structure.

[0025] Meanwhile, in this embodiment of the invention, a flowing medium is introduced into the opposing gap between the first electrode plate and the third electrode plate, so that the flowing medium forms a continuous flowing medium region spanning the opposing gap in at least a portion of the directly opposite area of ​​the first electrode plate and the third electrode plate, thereby reducing the restriction of the coupling capacitance by the air medium in this region and thus improving the main coupling capacitance between P1 and P3.

[0026] like Figure 1 As shown, this embodiment provides a capacitive wireless power transfer coupling structure based on the spatial distribution control of a flowing medium, including a first electrode P1, a second electrode P2, a third electrode P3, and a fourth electrode P4. The first electrode P1 and the second electrode P2 are installed on the shore side, while the third electrode P3 and the fourth electrode P4 are installed on the ship side. The first electrode P1 and the third electrode P3 are located above the water surface, and their relative arrangement forms the main coupling region above water. The second electrode P2 and the fourth electrode P4 are located below the water surface, and their relative arrangement forms the main coupling region underwater.

[0027] The first electrode plate P1, the second electrode plate P2, the third electrode plate P3, and the fourth electrode plate P4 are all insulating coated electrodes. Each electrode plate includes a conductive metal layer and an insulating layer covering the outer surface of the conductive metal layer. The conductive metal layer can be made of aluminum, copper, stainless steel, or other conductive metal. The insulating layer can be made of FR4, epoxy resin, polytetrafluoroethylene, plastic, ceramic, or other water-resistant insulating materials. The thickness of the insulating layer can be from 0.1 mm to 5 mm, preferably from 0.5 mm to 3 mm.

[0028] The phrase "the first electrode plate P1 and the third electrode plate P3 are located in the air region above the water surface" in this invention refers to the fact that the first electrode plate P1 and the third electrode plate P3 are installed above the ambient water surface, and does not mean that they are always in contact with the air medium during operation. When the flowing medium supply assembly is working, the flowing medium enters the gap between the first electrode plate P1 and the third electrode plate P3 and comes into contact with the outer surface of the insulating layer on their opposite sides.

[0029] It should be noted that in this embodiment, both the second electrode plate P2 and the fourth electrode plate P4 are isolated from the water medium by insulating layers. The underwater main coupling channel between P2 and P4 is composed of the insulating layer of the P2 electrode plate, the conductive medium (water), and the insulating layer of the P4 electrode plate in sequence. Displacement current is mainly formed within the insulating layer, while conduction current can be formed within the water medium. Together, these three elements constitute a series equivalent channel under high-frequency AC conditions. The insulating layers covering all four electrodes prevent direct conduction between the flowing medium and the metal conductive layer, improving the system's corrosion resistance, accidental contact prevention, and operational safety.

[0030] The coupling structure further includes a flow medium supply assembly. The flow medium supply assembly is used to introduce the flow medium into the opposing gap between the first electrode plate and the third electrode plate, so that the flow medium forms a continuous flow medium region spanning the opposing gap in at least a portion of the directly opposite regions of the first electrode plate P1 and the third electrode plate P3.

[0031] like Figure 2 As shown, the distance between the plates is... d a The maximum thickness of the flowing medium along the direction of the main electric field within the gap between P1 and P3 is: hf Under the preferred operating condition, the flowing medium crosses the opposing gaps P1 and P3 along the direction of the main electric field, forming a continuous flowing medium region spanning the opposing gaps. Therefore: (1); Equation (1) indicates that the flowing medium extends from the opposite insulating surface of P1 to the opposite insulating surface of P3 in the corresponding opposite region. It does not mean that the flowing medium must cover the back surface of P1 or P3, nor does it mean that the flowing medium must surround the entire plate.

[0032] By adjusting the operating state of the water pump or the liquid supply state of the outlet, the supply state of the flowing medium entering the gap between the first electrode plate P1 and the third electrode plate P3 is changed, so that the flowing medium forms a continuous medium region spanning the gap in at least a portion of the directly opposite areas of P1 and P3. That is, it is not necessary for all directly opposite areas of P1 and P3 to form a continuous flowing medium region spanning the gap. The liquid supply state can be set or adjusted according to the electrode spacing, the outlet size, and the actual distribution of the flowing medium. This invention does not use a single flow rate value or average flow velocity value as the sole basis for judging whether the flowing medium has reached the target spatial distribution state.

[0033] like Figure 3 , 4 As shown, the distance between the outer surfaces of the opposing insulating layers of the first electrode P1 and the third electrode P3 is defined as the spacing between the electrodes on the water. d a The distance between the outer surfaces of the opposing insulating layers of the second electrode P2 and the fourth electrode P4 is defined as the underwater electrode spacing. d w .in, d a Used to characterize the relative distance between P1 and P3 within the main coupling region above water. d w Used to characterize the relative distance between P2 and P4 within the underwater main coupling region. d a and d w The values ​​can be equal, or they can be set differently depending on the shore-side installation space, the ship's draft, the robotic arm's adjustment range, and underwater installation conditions. In a preferred embodiment, d a and d w The value is 10 mm. The four electrode plates can be rectangular, square, or rounded rectangular plates. Preferably, all four electrode plates are square plates with the same area. The side length of the square electrode plate... lThe thickness ranges from 100mm to 1000mm. In one specific embodiment, the first electrode plate P1, the second electrode plate P2, the third electrode plate P3, and the fourth electrode plate P4 are all made of square aluminum plates with a side length of 300mm, and the thickness of the metal conductive layer is... t p The insulation layer thickness is 2mm. t i It is 1mm.

[0034] like Figure 2 , 4 As shown, the flowing medium enters the opposing gap between P1 and P3 from above and flows downward along the opposing gap. In the preferred operating state, the flowing medium forms a continuous medium region across the opposing gap in the area directly opposite P1 and P3 along the normal direction of the opposing insulating surfaces of P1 and P3, that is, it satisfies formula (1).

[0035] (1); Formula (1) indicates that the flowing medium extends from the opposite insulating surface of P1 to the opposite insulating surface of P3 in the corresponding opposite region. It does not mean that the flowing medium must cover the back surface of P1 or P3, nor does it mean that the flowing medium must surround the entire plate.

[0036] When the flowing medium occupies only a portion of the opposing gap along the direction of the main electric field and does not form a continuous flowing medium region extending from the opposing insulating surface of P1 to the opposing insulating surface of P3, there is still air medium distributed along the direction of the main electric field in the region, and its effect on improving the coupling capacitance between P1 and P3 is relatively limited.

[0037] like Figure 1 and Figure 4 As shown, the flowing medium supply assembly includes a water pump, a water supply pipe, a return water tank, and a water outlet. The water pump draws the flowing medium from the water area below and delivers it through the water supply pipe to the opposing gap between the first electrode plate P1 and the third electrode plate P3. The water outlet can be an elongated outlet, a perforated array outlet, or other outlet form capable of introducing the flowing medium into the opposing gap. The specific shape of the water outlet does not constitute a limitation on the scope of protection of this invention.

[0038] The return water tank is located below the first electrode plate P1 and the third electrode plate P3, and above the second electrode plate P2 and the fourth electrode plate P4. The return water tank is made of insulating material and has multiple dispersed return water holes at its bottom. After flowing out from between the first electrode plate P1 and the third electrode plate P3, the flowing medium first enters the return water tank and then flows back to the water surface through the multiple return water holes. The diameter, number, and arrangement of the return water holes are predetermined based on the normal liquid supply required to maintain the continuous flow of the medium across the gap between P1 and P3. During normal operation, the average drainage capacity of the return water tank is not less than the average amount of flowing medium entering the return water tank. After flowing out from the main coupling area above the water between the first and third electrode plates, the flowing medium enters the return water tank and then flows back to the water surface below in the form of droplets, intermittent short liquid columns, or dispersed water flows through the return water holes. The above structure avoids the flow medium from connecting the main coupling area above the water and the water surface below in the form of a continuous water column, thereby reducing the possibility of forming a stable continuous conductive water body between the main coupling area above the water and the water body below, and thus reducing the risk of cross coupling, self-coupling and conductive loss caused by the continuous conductive water body.

[0039] Let the average liquid supply required for normal operation in one embodiment be... Q The average drainage capacity of the return water tank within the set liquid level range is Q a Normal operating conditions should meet the following requirements: (2); Equation (2) is the design matching condition between the liquid supply state and the drainage capacity of the return water tank. Q a It can be determined through fluid simulation or experiments.

[0040] The following is combined with Figure 5 , 6 The equivalent circuit and formulas of this invention will be explained. To facilitate the explanation of the main coupling mechanism, Figure 5 , 6 The main considerations are the main surface coupling channel between the first electrode plate P1 and the third electrode plate P3, and the main underwater coupling channel between the second electrode plate P2 and the fourth electrode plate P4.

[0041] The coupling mechanism of capacitive wireless power transfer can be described by the Ampere-Maxwell equations: (3); in, The magnetic field strength, For conduction current density, This represents the electric displacement vector. In this embodiment, the conduction current in the water medium is mainly determined by the conductivity of the water medium, while the displacement current in the insulating layer is mainly determined by the dielectric constant of the insulating layer and the AC voltage.

[0042] For the insulating layer, when the conductivity is negligible, its equivalent capacitance... Can be written as (4); in, The vacuum permittivity, The relative permittivity of the insulating layer, Approximately take the area of ​​the plate. This refers to the thickness of the insulation layer. (Due to the thickness of the insulation layer...) Typically much smaller than the edge length of the electrode plate. l In the approximate calculation of the capacitance of the insulating layer, the edge effect can be ignored.

[0043] Insulating materials exhibit dielectric losses, which are represented by loss resistance. If a series equivalent form is used, then the... k The series equivalent loss resistance of the block electrode insulation layer can be written as: (5); in, For the first k The series equivalent loss resistance of the insulating layer of the block electrode plate. The dielectric loss tangent of the insulating material. For the system operating frequency, For the first k The equivalent capacitance of the insulating layer of the block plate.

[0044] When the flowing medium fills the opposing gap between P1 and P3 along the direction of the main electric field, we have: (6); Since the flowing medium is seawater or water with a certain conductivity, in this embodiment, the intermediate flowing water medium between P1 and P3 is equivalent to a resistor. : (7); in, The conductivity of the flowing medium, Let be the effective conductive cross-sectional area perpendicular to the direction of the main conductive current in the flowing medium. When the flowing medium completely fills the main coupling region directly opposite the first electrode P1 and the third electrode P3, and the effects of edge current propagation and non-uniform flow are ignored, it can be approximated that: (8); The main coupling channel on the water can be equivalently represented as a series branch consisting of the insulating layer of the first plate P1, the resistance of the flowing water dielectric, and the insulating layer of the third plate P3. The equivalent capacitance of the flowing medium crossing the opposing gap between P1 and P3 along the direction of the main electric field is also considered. for: (9); The equivalent series resistance between the first plate P1 and the third plate P3 for: (10); Substituting equations (5) to (7) into equation (10), we get: (11); Since the insulating layer material, thickness, and geometric dimensions of the first electrode P1 and the third electrode P3 are the same, then: (12); (13); At the same time, equation (11) can be simplified to: (14); Therefore, when the flowing medium crosses the opposing gap between P1 and P3 along the direction of the main electric field, the impedance of the main coupling channel above water between the first electrode P1 and the third electrode P3 is... It can be represented as: (15); j represents a complex number. This is the system angular frequency.

[0045] For the underwater water medium region between the second plate P2 and the fourth plate P4, since both plates are completely submerged in the water medium and are both insulated plates, their insulation layer capacitance can also be approximated as coupling through the two main surfaces. Therefore: (16); The underwater medium between the second electrode plate P2 and the fourth electrode plate P4 can be considered as a resistor. : (17); in, This is the equivalent path length between P2 and P4 along the direction of the main conducting current. The conductivity of the underwater water medium, This refers to the effective conductive cross-sectional area perpendicular to the direction of the main conductive current in the underwater conductive path. It is not equal to the electrode area; rather, it should be understood as the equivalent conductive cross-sectional area determined by the geometry of the water body and the current distribution. The accurate value can be obtained through finite element simulation.

[0046] Since the insulating layer material, thickness, and geometric dimensions of the second electrode P2 and the fourth electrode P4 are the same, then: (18); (19); To facilitate subsequent system analysis, the surface main coupling channel and the underwater main coupling channel can be further equivalently represented as the system's main coupling branches. The system's main coupling branches are equivalent to... C 13 , R 13 , C 24 , R 24 The series combination. The system's main coupling equivalent capacitance. C M for: (20); System main coupling equivalent series resistance R M for: (twenty one); Therefore, considering only the equivalent conditions of the surface main coupling channel and the underwater main coupling channel, the main coupling branch of the system at the angular frequency ω Equivalent impedance under It can be represented as: (twenty two); Equation (22) is used to characterize the equivalent impedance of the main coupling branch of the coupled structure at a given operating frequency. The real part of the equivalent impedance is... R M This is used to characterize the equivalent loss formed by the flowing medium, underwater water medium, and insulating layer dielectric loss; the imaginary part of the equivalent impedance is... It is used to characterize the capacitive reactance of the main coupled branch.

[0047] The equivalent impedance It can be used as a lumped parameter model of the coupled structure in the equivalent circuit of a capacitor-type wireless power transmission system, and together with the equivalent parameters of the inverter, compensation network, rectifier, and load, it can be used to establish the system loop equations, thereby providing a basis for the analysis of operating frequency selection, compensation network parameter configuration, transmission loss, etc. The specific parameters of the compensation element should be determined according to the compensation network topology, target transmission power, input voltage, and load conditions. This invention does not limit the specific topology of the compensation network.

[0048] like Figure 7As shown, this embodiment also provides a capacitor-type wireless power transfer system, including a DC power supply, an inverter, a compensation network, the aforementioned coupling structure, a rectifier, and a load. The output terminal of the DC power supply is connected to the inverter, which converts DC power into high-frequency AC power and connects it to the first plate P1 and the second plate P2 through the compensation network. After receiving energy, the third plate P3 and the fourth plate P4 are connected to the rectifier through the compensation network. The rectifier converts the high-frequency AC power into DC power and supplies power to the load.

[0049] like Figure 8 As shown, the flow medium control method of the present invention may include the following steps.

[0050] Step 1: Obtain the distance between the first electrode plate P1 and the third electrode plate P3 above water. d a And P1 and P3 are positioned opposite each other to form the main coupling gap on the water.

[0051] Step 2, based on the opposing gap d a Multiple candidate liquid supply rates are set for the plate widths of the first electrode P1 and the third electrode P3, the outlet type, the characteristics of the flowing medium, and the flow boundary conditions. ,in: (twenty three); In the formula, A The effective flow area of ​​the outlet. For the first i The average flow velocity at the outlet under each candidate liquid supply condition was determined. The spatial distribution of the flowing medium within the opposing regions of P1 and P3 under each candidate liquid supply rate was obtained through fluid simulation or liquid supply experiments. The flow medium was observed to continuously cross the opposing gaps between P1 and P3 along the main electric field direction within a preset observation period, maximizing the thickness of the flowing medium. h f Keep as d a When the corresponding candidate liquid supply quantity satisfies the formation conditions of the continuous flow medium region across the gap, that is, the average liquid supply quantity Q.

[0052] Step 3: After determining the average liquid supply Q of the conditions formed in Step 2, determine the corresponding outlet type and average water flow rate as the liquid supply state under normal working conditions.

[0053] Step 4: Based on the water drop range after the flowing medium is discharged from the gap between P1 and P3, determine the installation position and receiving opening size of the return water tank so that the return water tank covers the main water drop area of ​​the flowing medium.

[0054] Step 5: Based on the flow rate Q entering the return water tank under normal operating conditions, determine the diameter, number, and arrangement of the return water holes to ensure the average drainage capacity Q of the return water tank. a satisfy .

[0055] Step six: Start the flow medium supply assembly to deliver the flow medium to the opposing gap between P1 and P3 in the liquid supply state determined in step three, so that the flow medium forms and maintains the cross-gap continuous flow medium region described in step two.

[0056] Step 7: The flowing medium exiting from the gap between P1 and P3 enters the return water tank determined according to Steps 5 and 6, and is discharged through the pre-set return water hole.

[0057] like Figure 9 and Figure 10 As shown, the electric field distribution under different spatial distributions of flowing media can be compared through finite element simulation. Figure 9 In the process, the medium between the first plate P1 and the third plate P3 is mainly air. The main coupling channel on the water is limited by the low dielectric constant of air, and the main coupling capability between the first plate P1 and the third plate P3 is relatively weak. Figure 10 In this process, the flowing medium enters and fills the main coupling region above water between the first electrode P1 and the third electrode P3. At this time, the air layer between P1 and P3 is replaced by the flowing medium, thereby increasing the main coupling capacitance between the first electrode P1 and the third electrode P3.

[0058] like Figure 11 As shown, the main coupling capacitance C between the first plate P1 and the third plate P3 under different spatial distributions of the flowing medium is compared through finite element simulation. 13 Spacing between upper electrode plates d a The curve illustrates the change in the main coupling capacitance of the water as the flowing medium crosses the opposing gaps between P1 and P3 along the direction of the main electric field. d a The positive effects of the changes.

[0059] Figure 12 The main coupling capacitance C between the second plate P2 and the fourth plate P4 under different spatial distributions of the flowing medium. 24 The curve shows the change in C. This curve illustrates that after the flowing medium crosses the opposing gaps between P1 and P3 along the direction of the main electric field, C... 24 Basically unchanged.

[0060] like Figure 13 As shown, the total coupling capacitance C of the system under different spatial distributions of the flowing medium is compared through finite element simulation. M Spacing between upper electrode plates d aThe curve illustrates the effect of this invention in increasing the total coupling capacitance of the system by adjusting the spatial distribution of the flowing medium to enhance the main coupling capacitance between the first electrode P1 and the third electrode P3.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any equivalent substitutions, modifications, or combinations made within the spirit and principles of the present invention regarding the method of supplying the flowing medium, the shape of the return water tank, the arrangement of the return water holes, the size of the electrode plate, the insulating layer material, the control strategy, or the circuit topology should be included within the scope of protection of the present invention.

Claims

1. A capacitive wireless power transfer coupling structure based on a flowing medium, characterized in that, include: The transmitter-side conductor unit includes a first electrode plate and a second electrode plate; The receiving-side conductor unit includes a third electrode plate and a fourth electrode plate; The first electrode plate and the third electrode plate are both disposed in the air medium above the water surface, and the first electrode plate and the third electrode plate are arranged opposite to each other to form the main coupling region above the water. Both the second electrode plate and the fourth electrode plate are disposed in a conductive medium below the water surface. The second electrode plate and the fourth electrode plate are arranged opposite to each other to form an underwater main coupling region. A flow medium supply assembly is used to introduce a flow medium into the opposing gap between the first electrode plate and the third electrode plate, such that a continuous flow medium region spanning the opposing gap is formed between the first electrode plate and the third electrode plate, wherein the dielectric constant of the flow medium is greater than that of air.

2. The capacitive wireless power transfer coupling structure based on a flowing medium as described in claim 1, characterized in that, The surfaces of the first electrode plate, the third electrode plate, the second electrode plate, and the fourth electrode plate are all covered with an insulating layer.

3. The capacitive wireless power transfer coupling structure based on a flowing medium as described in claim 1, characterized in that, The distance between the first electrode plate and the third electrode plate is... d a The maximum thickness of the continuous flow medium region along the main electric field direction is: h f ,satisfy .

4. The capacitive wireless power transfer coupling structure based on a flowing medium as described in claim 1, characterized in that, The fluid supply assembly includes a water pump, a water pipe, a water outlet, and an insulated return water tank. The water pump, water pipe, and water outlet introduce the fluid into the opposing gap between the first electrode plate and the third electrode plate. The insulated return water tank is used to receive the fluid flowing out between the first electrode plate and the third electrode plate.

5. The capacitive wireless power transfer coupling structure based on a flowing medium as described in claim 4, characterized in that, The insulating return water tank is provided with multiple dispersed return water holes.

6. The capacitive wireless power transfer coupling structure based on a flowing medium as described in claim 4, characterized in that, The average drainage rate of the insulating return water tank per unit time is not less than the average supply rate of the flowing medium supply component per unit time.

7. The capacitive wireless power transfer coupling structure based on a flowing medium as described in claim 1, characterized in that, The conductive medium is the same substance as the flowing medium.

8. The capacitive wireless power transfer coupling structure based on a flowing medium as described in claim 1, characterized in that, The transmitting-side conductor unit is mounted on the shore-side robotic arm, and the receiving-side conductor unit is mounted on the ship-side robotic arm.

9. A method for controlling a capacitive wireless power transfer coupling structure based on a flowing medium, characterized in that, The capacitive wireless power transfer coupling structure includes: The transmitter-side conductor unit includes a first electrode plate and a second electrode plate; The receiving-side conductor unit includes a third electrode plate and a fourth electrode plate; The first electrode plate and the third electrode plate are both disposed in the air medium above the water surface, and the first electrode plate and the third electrode plate are arranged opposite to each other to form the main coupling region above the water. Both the second electrode plate and the fourth electrode plate are disposed in a conductive medium below the water surface. The second electrode plate and the fourth electrode plate are arranged opposite to each other to form an underwater main coupling region. A flow medium supply assembly is used to introduce a flow medium into the opposing gap between the first electrode plate and the third electrode plate, such that a continuous flow medium region spanning the opposing gap is formed between the first electrode plate and the third electrode plate, wherein the dielectric constant of the flow medium is greater than that of air. The flowing medium supply assembly includes a water pump, a water supply pipe, a water outlet, and an insulating return water tank. The water pump, water supply pipe, and water outlet introduce the flowing medium into the opposing gap between the first electrode plate and the third electrode plate. The insulating return water tank is used to receive the flowing medium flowing out between the first electrode plate and the third electrode plate. The insulating return water tank is provided with multiple dispersed return water holes. The control method includes the following steps: Obtain the relative distance between the first electrode plate and the third electrode plate. d a ; According to the opposing gap d a The average liquid supply rate Q of the flow medium supply component is determined by considering the widths of the first and third plates, the liquid supply form of the flow medium supply component, the characteristics of the flow medium, and the flow boundary conditions. Based on the water droplet range after the flowing medium is discharged from the opposing gap between the first electrode plate and the third electrode plate, determine the installation position and receiving opening size of the insulating return water tank so that the insulating return water tank covers the water droplet area of ​​the flowing medium. Determine the diameter, number, and arrangement of the return water holes to ensure that the average drainage rate Q per unit time of the insulating return water tank is [value missing]. a satisfy ; The fluid supply assembly is activated, and the fluid is supplied to the gap between the first and third plates according to the average supply volume Q per unit time.

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