Capacitance-inductance integrated coupling coil

Abstract

The invention provides a capacitance-inductance integrated coupling coil, and belongs to the technical field of wireless electric energy transmission, the capacitance-inductance integrated coupling coil comprises multiple layers of insulating media, multiple layers of positive coils and multiple layers of negative coils, and the multiple layers of insulating media, the multiple layers of positive coils and the multiple layers of negative coils are stacked and alternately arranged according to the sequence of the insulating media, the positive coils, the insulating media and the negative coils; wherein the anode coils of all layers are connected in parallel, and the cathode coils of all layers are connected in parallel. According to the invention, the compensation capacitor is generated in the coupling coil through the alternate stacking structure of the insulation, the positive electrode, the insulation and the negative electrode, so that the problems of complex structure, low reliability, limited power density and the like of a traditional WPT system are solved, and the design universality is improved.

Description

Technical Field

[0001] This application relates to the field of wireless power transmission technology, and in particular to a capacitive-inductive integrated coupling coil. Background Technology

[0002] With people's increasing pursuit of convenient lifestyles, the development of safe, stable, and flexible charging methods for electrical equipment is crucial. Since there is no mechanical contact between the primary and secondary sides of the coupling mechanism, Wireless Power Transfer (WPT) technology can achieve "wireless" power transfer. When applied to charging electrical equipment, it offers the following advantages: There are no exposed interfaces, thus eliminating contact sparks, wear risks, and maintenance issues, making it safer and more reliable; the coupling mechanism can be sealed, allowing charging to be completed even in dusty or rainy environments, unrestricted by the usage environment; it easily achieves automated and intelligent charging without user intervention, enabling instant charging and a better user experience; and when applied to the electric vehicle field, it facilitates vehicle-to-grid (V2G) interaction. The unregulated charging of large-scale electric vehicles will have a significant impact on the power grid. Electric vehicle battery energy storage is the optimal choice for distributed, small-scale, and short-cycle energy storage. As the scale of electric vehicles increases, intelligent and orderly charging and vehicle-to-grid (V2G) will become important supports for carbon neutrality. V2G requires the electric vehicle to remain connected to the grid. Wired charging means maintaining a connection between the vehicle and the charging gun, while with the WPT system, V2G can be achieved simply by the vehicle being parked above the charging coil. When applied to inspection robots, electric vehicles, and rail transit, charging can be achieved while the vehicle is in motion, i.e., dynamic power supply, when the coupling mechanism is laid along the primary side of the line. This helps reduce the number of onboard batteries, thereby reducing vehicle weight and cost, alleviating or even eliminating range anxiety, and eliminating the impact on the urban landscape. In summary, the WPT system achieves electrical and physical isolation between the primary and secondary sides, naturally possessing advantages such as safety, convenience, and flexibility. Once matured, it will bring revolutionary changes to the way electrical equipment is recharged, possessing enormous scientific and commercial value, and therefore has attracted the attention and favor of academia and industry.

[0003] Inductively coupled WPT systems utilize the principle of electromagnetic induction to achieve contactless energy transfer. The core carrier of this energy transfer—the coupling mechanism—can be considered a loosely coupled transformer. For example... Figure 1As shown, compared to traditional transformers, the magnetic cores of the primary and secondary sides of the WPT system coupling mechanism are independent and have no mechanical contact. A typical coupling mechanism consists of two parts: the primary and secondary sides, mainly composed of coils and magnetic cores. The magnetic core serves to enhance coupling and shield leakage flux. To enhance electromagnetic shielding and prevent leakage flux from interfering with other electronic equipment, a shielding plate is usually placed on the other side of the magnetic core in engineering applications. In some applications, the magnetic core is even eliminated, and power transfer is achieved solely through coupling between the coils. Due to the spacing between the primary and secondary coils and the fact that they are not wound on the same magnetic core, the coupling coefficient is generally low, typically between 0.05 and 0.3. Because of the low coupling coefficient and significant leakage flux of the coupling mechanism, a resonant compensation network is usually added between the converter and the coupling coils on the primary and secondary sides to reduce system reactive power and improve transmission efficiency. Figure 2 As shown, based on the connection method of capacitors and inductors, common resonant compensation topologies can be divided into series (S), parallel (P), and series-parallel (LCL, LCC) types. Different compensation topologies can be used on the primary and secondary sides to form the compensation network of the WPT system. Currently, the compensation capacitors widely used in WPT systems are mainly of two forms: single-unit capacitors and on-board capacitor matrices. Single-unit compensation capacitors are usually composed of one or several capacitors connected in series and parallel. Metallized polypropylene film capacitors (MKP) have advantages such as large specific capacitance, low dielectric loss, high insulation resistance, and good stability, and are therefore commonly used as single-unit compensation capacitors. Compared with other capacitors, ceramic capacitors have advantages such as higher operating temperature, large specific capacitance, good moisture resistance, and low dielectric loss, but their single-unit capacitance and withstand voltage and current values ​​are generally smaller. Therefore, in practical applications, hundreds or thousands of capacitors are soldered onto a printed circuit board (PCB) in series and parallel to increase their capacitance and withstand voltage and current values, forming an on-board capacitor matrix. As can be seen from the above analysis, the traditional separate structure of coupling coil and compensation capacitor leads to increased system cost and complex structure, which limits the improvement of system power density and restricts its use in some places with strict requirements on system size.

[0004] Therefore, there is an urgent need for a new, simplified system architecture to improve system integration and increase system power density. Summary of the Invention

[0005] This application provides a capacitive-inductor integrated coupling coil to solve the shortcomings of the traditional separate coupling coil and compensation capacitor structure in the prior art, which leads to increased system cost, complex structure, and limited power density improvement of the system.

[0006] This application provides a capacitive-inductive integrated coupling coil, including multiple layers of insulating medium, multiple layers of positive coil and multiple layers of negative coil, wherein the multiple layers of insulating medium, the multiple layers of positive coil and the multiple layers of negative coil are stacked and alternately arranged in the order of insulating medium, positive coil, insulating medium and negative coil; In this configuration, the positive coils of each layer are connected in parallel, and the negative coils of each layer are connected in parallel.

[0007] According to the present application, a capacitive-inductive integrated coupling coil is provided, wherein each of the positive coils is connected by lamination, vias or welding.

[0008] According to the present application, a capacitive-inductive integrated coupling coil is provided, wherein each of the negative pole coils is connected by lamination, vias or welding.

[0009] According to the present application, a capacitive-inductive integrated coupling coil is provided, wherein the positive coil is connected to the adjacent insulating medium by lamination, spraying or bonding.

[0010] According to the capacitive-inductive integrated coupling coil provided in this application, the insulating medium is made of polyester film, polypropylene film, polyimide or epoxy resin.

[0011] According to the capacitive-inductive integrated coupling coil provided in this application, the more turns the positive coil or the negative coil has, the shorter the turn spacing, the larger the cross-sectional area, and the shorter the layer spacing, the greater the inductance of the positive coil or the negative coil.

[0012] According to the capacitive-inductive integrated coupling coil provided in this application, the lower the resistivity, the larger the cross-sectional area, and the more layers of the positive or negative coil, the higher the current carrying capacity.

[0013] According to the capacitive-inductive integrated coupling coil provided in this application, the higher the dielectric constant and the lower the thickness of the insulating medium, the larger the facing area of ​​the positive coil and the negative coil, and the larger the capacitance of the capacitive-inductive integrated coupling coil.

[0014] According to the capacitive-inductive integrated coupling coil provided in this application, the higher the dielectric constant and the thicker the insulating medium, the higher the withstand voltage rating of the insulating medium.

[0015] This application also provides a wireless power transmission system, including at least one capacitive-inductive integrated coupling coil as described in any of the preceding claims.

[0016] The capacitive-inductive integrated coupling coil provided in this application includes multiple layers of insulating dielectric, multiple layers of positive coils, and multiple layers of negative coils. These layers are arranged in an alternating stacked sequence of insulating dielectric, positive coil, insulating dielectric, and negative coil. Each layer of positive coils is connected in parallel, and each layer of negative coils is connected in parallel. This application provides inductance through the coil layers, and adjacent coils of opposite polarities naturally form capacitance with the intermediate insulating dielectric. Inductance and capacitance are simultaneously achieved within the same space, eliminating the need for additional capacitors and connecting wires, reducing system size, increasing power density, and making it suitable for space-sensitive applications. Furthermore, the equivalent inductance and equivalent capacitance can be precisely controlled by adjusting the parallel connection method of the positive and negative coils (full parallel or grouped parallel), the thickness of the interlayer dielectric, the dielectric constant, the number of turns, the number of layers, and the area of ​​the coils. This means that different power levels and coupling coefficient scenarios can be adapted without replacing external components, naturally achieving parameter matching required for compensation topologies such as SS, SP, and LCL, thus improving the versatility of the design. In summary, this application incorporates the compensation capacitor within the coupling coil through an alternating stacked structure of insulation, positive electrode, insulation, and negative electrode. This not only solves the problems of complex structure, low reliability, and limited power density in traditional WPT systems, but also improves design versatility. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the conventional transformer and WPT system provided in this application; Figure 2 This is a schematic diagram of the structure of a compensation network in the prior art; Figure 3 This is a schematic diagram of the structure of the capacitive-inductor integrated coupling coil provided in this application; Figure 4 This is a schematic diagram of the equivalent circuit of the capacitive-inductive integrated coupling coil provided in this application; Figure 5 This is a bird's-eye view of the capacitive-inductive integrated coupling coil provided in this application; Figure 6 This is a schematic diagram of the planar helical coil provided in this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] It should be noted that in the description of the embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The terms "upper," "lower," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; and they can be internal connections between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, without limiting the number of objects; for example, a first object can be one or more. Furthermore, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects have an "or" relationship.

[0022] The following is combined Figures 3-6 This application describes the capacitive-inductive integrated coupling coil provided in the embodiments of this application.

[0023] Figure 3 This is a schematic diagram of the structure of the capacitive-inductive integrated coupling coil provided in this application, as shown below. Figure 3As shown, the coupling coil includes multiple layers of insulating dielectric, multiple layers of positive coils, and multiple layers of negative coils. The multiple layers of insulating dielectric, the multiple layers of positive coils, and the multiple layers of negative coils are stacked and alternately arranged in the order of insulating dielectric, positive coil, insulating dielectric, and negative coil. Among them, the positive coils of each layer are connected in parallel, and the negative coils of each layer are connected in parallel.

[0024] Here, the positive and negative coils are open patterns formed by conductive metal materials (such as gold, silver, copper, and aluminum) according to a preset pattern, and have the function of inductance.

[0025] In this embodiment, the capacitive-inductive integrated coupling coil mainly includes three types of basic units, which are stacked alternately in a specific order: Multilayer insulating dielectric, as an electrical isolation and dielectric material, not only prevents short circuits between conductors, but also constitutes the dielectric layer of the capacitor; Multilayer positive coils, made of conductive materials (such as copper foil or printed wires), are spiral or other closed-loop forms used to form inductors and serve as one plate of a capacitor; The multi-layer negative coil has a similar structure to the positive coil, but with the opposite potential. It also functions as an inductor and the other plate of a capacitor.

[0026] The above three basic units are stacked using the following repeating units: insulating medium → positive coil → insulating medium → negative coil → insulating medium → positive coil → …

[0027] In practice, all positive coils are electrically connected to the same node (such as the input terminal or the positive terminal of a high-frequency excitation source), which is equivalent to a composite inductor with low inductive reactance and high current capacity, and also serves as the positive terminal of a capacitor. All negative coils are connected to a common reference point (such as ground or the negative terminal), forming the negative terminal of the capacitor and simultaneously creating a parallel inductor structure.

[0028] Figure 4 This is a schematic diagram of the equivalent circuit of the capacitive-inductive integrated coupling coil provided in this application, as shown below. Figure 4 As shown, where L 1 represents the self-inductance of the positive and negative coils. M C1 is the mutual inductance between the positive and negative coils, and C2 is the capacitance between the positive and negative coils. The positive and negative coils have the same shape but opposite winding directions, which conforms to the principle of series connection of like terminals, thus forming an equivalent total inductance L. 总 =2L+M. The parasitic capacitances are connected in parallel, and the total capacitance C = 2C1.

[0029] Figure 5 This is a bird's-eye view of the capacitive-inductive integrated coupling coil provided in this application, as shown below. Figure 5 As shown, the shapes of the positive and negative coils can be set to circles, rectangles, DD type or other shapes as needed, and the specific shapes are not limited here.

[0030] The periodic stacked structure of insulating medium, positive electrode, insulating medium, and negative electrode provided in this application embodiment, with an insulating medium sandwiched between adjacent positive and negative electrode coils, constitutes a parallel plate capacitor structure. Due to the multi-layer stacking, multiple capacitor units are connected in parallel, significantly increasing the total capacitance. Each layer of positive electrode coil itself constitutes an inductor circuit, and the layers are connected in parallel, reducing the equivalent inductance value but enhancing the current carrying capacity. Each layer of negative electrode coil itself constitutes an inductor circuit, and the layers are connected in parallel, reducing the equivalent inductance value but enhancing the current carrying capacity. The positive and negative electrode coils are spatially close to each other and arranged in a coplanar or near-coplanar manner, which can achieve strong magnetic coupling and is suitable for applications such as wireless power transmission and resonant coupling.

[0031] The capacitive-inductive integrated coupling coil provided in this application includes multiple layers of insulating dielectric, multiple layers of positive coils, and multiple layers of negative coils. These layers are arranged in an alternating stacked sequence of insulating dielectric, positive coil, insulating dielectric, and negative coil. Each layer of positive coils is connected in parallel, and each layer of negative coils is connected in parallel. This application provides inductance through coil layers, and adjacent coils of opposite polarities naturally form capacitance with the intermediate insulating dielectric. Inductance and capacitance are simultaneously achieved within the same space, eliminating the need for additional capacitors and connecting wires, reducing system size, increasing power density, and making it suitable for space-sensitive applications. Furthermore, the equivalent inductance and equivalent capacitance can be precisely controlled by adjusting the parallel connection method of the positive and negative coils (full parallel or grouped parallel), the thickness of the interlayer dielectric, the dielectric constant, the number of turns, the number of layers, and the area of ​​the coils. This means that different power levels and coupling coefficient scenarios can be adapted without replacing external components, naturally achieving parameter matching required for compensation topologies such as SS, SP, and LCL, thus improving the versatility of the design. In summary, this application incorporates the compensation capacitor within the coupling coil through an alternating stacked structure of insulation, positive electrode, insulation, and negative electrode. This not only solves the problems of complex structure, low reliability, and limited power density in traditional WPT systems, but also improves design versatility.

[0032] In an optional embodiment, the positive coils are connected by lamination, vias, or welding.

[0033] In the embodiments of this application, one or a combination of three interconnection methods, namely lamination, via, and soldering, are used.

[0034] Laminated bonding involves designing the ends of the positive coils in each layer as alignable contact areas during the manufacturing process of a multilayer structure. Under high temperature and high pressure lamination, adjacent conductors directly physically contact each other and form a metallurgical bond (such as copper-copper diffusion bonding). This bonding method is suitable for flexible circuits, metal foil stacked structures, or LTCC (low-temperature co-fired ceramic) and other integral sintering / lamination processes. It requires no additional interconnecting components, has a compact structure, and minimal parasitic inductance.

[0035] Via connections involve drilling and metallizing (e.g., electroplating copper) holes in the insulating dielectric layer to form vertical conductive channels (i.e., "vias"), connecting the positive coil terminals of different layers in series or parallel to the same network. In the embodiments of this application, the positive coil leads of each layer are aligned at the same position; stacked vias or staggered vias penetrating multiple layers are provided at this position; all positive coils are connected to the common busbar of the top or bottom layer through vias. This connection method is suitable for standard multilayer PCBs, HDI (High-Density Interconnect) boards, integrated passive devices (IPD), etc.

[0036] Soldering connections are made after the layers are stacked, using external processes (such as reflow soldering, laser soldering, or wire bonding) to solder the leads of each positive coil layer to the same conductive pad or busbar. In practice, each coil layer has pre-reserved pads or gold fingers; solder balls, copper wire, or aluminum wire are used for cross-layer connections; and flexible leads or rigid-flexible structures can be used to achieve three-dimensional interconnection. This connection method is suitable for modular assembly, non-coplanar stacked structures, and applications requiring high maintainability.

[0037] The capacitive-inductive integrated coupling coil provided in this application embodiment connects the positive coil through lamination, vias, or soldering to form a parallel structure, thereby increasing the coil's current carrying capacity and meeting the needs of high-power / high-current scenarios. Lamination or vias are embedded interconnects with no exposed solder joints, offering superior vibration resistance and damp heat resistance compared to external soldering. In PCB / LTCC processes, via and lamination connections enable automated, high-precision mass production with high yields. Although soldering is an external connection, high-reliability connections can be achieved by using reflow soldering or gold-tin eutectic soldering. All interconnection methods ensure electrical consistency across layers, preventing "open circuits" on certain layers due to poor contact, which could lead to current redistribution or even thermal runaway.

[0038] In an optional embodiment, the negative coils are connected by lamination, vias, or welding.

[0039] In the embodiments of this application, one or a combination of three interconnection methods, namely lamination, via, and soldering, are used.

[0040] Laminated bonding involves designing the ends of the negative coils in each layer as alignable contact areas during the manufacturing process of a multilayer structure. Under high temperature and high pressure lamination, adjacent conductors directly physically contact each other and form a metallurgical bond (such as copper-copper diffusion bonding). This bonding method is suitable for flexible circuits, metal foil stacked structures, or LTCC (low-temperature co-fired ceramic) and other integral sintering / lamination processes. It requires no additional interconnecting components, has a compact structure, and minimal parasitic inductance.

[0041] Via connections involve drilling and metallizing (e.g., electroplating copper) holes in the insulating dielectric layer to form vertical conductive channels (i.e., "vias"), connecting the negative coil terminals of different layers in series or parallel to the same network. In this embodiment, the negative coil leads of each layer are aligned at the same position; stacked vias or staggered vias penetrating multiple layers are provided at this position; all negative coils are connected to the common busbar of the top or bottom layer through vias. This connection method is suitable for standard multilayer PCBs, HDI (High-Density Interconnect) boards, integrated passive devices (IPD), etc.

[0042] Soldering connections are made after the stack-up is completed, using external processes (such as reflow soldering, laser soldering, or wire bonding) to solder the leads of each negative coil layer to the same conductive pad or busbar. In practice, each coil layer has pre-reserved pads or gold fingers; solder balls, copper wire, or aluminum wire are used for cross-layer connections; and flexible leads or rigid-flexible structures can be used to achieve three-dimensional interconnection. This connection method is suitable for modular assembly, non-coplanar stack-up structures, and applications requiring high maintainability.

[0043] The capacitive-inductive integrated coupling coil provided in this application embodiment connects the negative coil through lamination, vias, or soldering to form a parallel structure, thereby increasing the coil's current carrying capacity and adapting to the needs of high-power / high-current scenarios. Lamination or vias are embedded interconnects with no exposed solder joints, offering superior vibration resistance and damp heat resistance compared to external soldering. In PCB / LTCC processes, via and lamination connections enable automated, high-precision mass production with high yields. Although soldering is an external connection, high-reliability connections can be achieved by using reflow soldering or gold-tin eutectic soldering. All interconnection methods ensure electrical consistency across layers, preventing "open circuits" on certain layers due to poor contact, which could lead to current redistribution or even thermal runaway.

[0044] In an optional embodiment, the positive coil is connected to the adjacent insulating medium by lamination, spraying, or bonding.

[0045] In the multilayer structure of a capacitive-inductive coupled coil, the positive coil (typically a metal conductor, such as copper foil, printed silver paste, or sputtered metal film) needs to be firmly attached to the adjacent insulating dielectric layer (such as polyimide PI, FR-4, ceramic, epoxy resin, LTCC green ceramic tape, etc.). To achieve this goal, embodiments of this application employ one or a combination of three connection processes: lamination, spraying, and bonding.

[0046] Laminated bonding involves stacking a pre-fabricated metal foil (positive electrode coil pattern) with an insulating dielectric film and then hot-pressing them under high temperature, high pressure, and a certain time to achieve a tight bond at the molecular level. This bonding method requires no additional adhesive layer at the interface (or uses a thermosetting adhesive film), resulting in high bonding strength and good thermal expansion matching.

[0047] Spray coating first forms a positive coil pattern on the surface of the insulating medium (e.g., screen-printed conductive silver paste, inkjet-printed nano-silver ink, laser direct writing, etc.); or it first deposits a metal layer (e.g., sputtering, evaporation) and then patterns it using photolithography; the conductor material undergoes physical intercalation or chemical bonding with the surface of the insulating medium during the spraying / deposition process. This connection method can achieve ultra-thin coils, and the interfacial bonding depends on the material's wettability and surface energy.

[0048] The adhesive bonding involves applying a special conductive or non-conductive adhesive (such as epoxy resin, acrylate, or anisotropic conductive adhesive ACF) between the insulating medium and the positive coil, and then achieving bonding through curing (heat, UV, or moisture).

[0049] The capacitive-inductor integrated coupling coil provided in this application embodiment, in a multi-layer stacked structure, if there is a weak interface (such as no bonding) between the coil and the dielectric, delamination or coil peeling is likely to occur under thermal cycling or mechanical impact. By laminating, spraying or bonding, a reliable connection between the positive coil and the insulating dielectric is achieved. This not only solves the mechanical integration problem in multi-layer structures, but also ensures the performance stability and long-term reliability of the capacitive-inductor integrated coupling coil in high-frequency, high-power, and miniaturized application scenarios from three dimensions: electromagnetic, thermal, and environmental reliability.

[0050] The connection method between the negative coil and the insulating medium is the same as that between the positive coil and the insulating medium, and will not be repeated here.

[0051] In optional embodiments, the insulating medium is made of polyester film, polypropylene film, polyimide or epoxy resin.

[0052] Understandably, the insulating medium is made of a non-conductive material with a high dielectric constant. This serves two purposes: firstly, it provides insulation between the positive and negative electrodes, preventing direct electrical connection between the coils; secondly, it acts as the dielectric material for the capacitor, thus creating a capacitor between the coils. The specific material used for the insulating medium is not limited here.

[0053] It is understood that the insulating medium is not limited to polyester film, polypropylene film, polyimide or epoxy resin, and other insulating materials can be selected according to actual usage requirements.

[0054] The capacitive-inductor integrated coupling coil provided in this application embodiment achieves synergistic optimization of materials, performance, process, and reliability by limiting the use of polyester film, polypropylene film, polyimide, or epoxy resin as the insulating medium. While ensuring electrical isolation and capacitive function, materials can be flexibly selected according to specific application requirements (frequency, power, cost, environment), thereby achieving significant advantages in high-frequency efficiency, thermal management, manufacturing yield, and long-term stability. This provides a solid material foundation for the engineering application of capacitive-inductor integrated coupling coils in wireless power transmission, radio frequency identification, and integrated passive devices.

[0055] In an optional embodiment, the more turns the positive coil or the negative coil has, the shorter the turn spacing, the larger the cross-sectional area, and the shorter the layer spacing, the greater the inductance of the positive coil or the negative coil.

[0056] In this embodiment, the inductance is adjusted by adjusting the number of turns, the turn spacing, the cross-sectional area, the layer spacing, and whether or not a magnetic core is added.

[0057] In a capacitive-inductive coupled coil, the positive and negative coils not only serve as the plates of a capacitor but also as the core conductor structure of the inductor. To achieve precise control of the system's resonant frequency, the self-inductance (L) of the coil needs to be flexibly adjusted. This application's embodiments achieve active design and optimization of the inductor through the following five structural parameters: number of turns (the number of turns the coil is wound), turn spacing (the distance between the centers of two adjacent turns), conductor cross-sectional area (the cross-sectional area of ​​a single turn), layer spacing (the vertical distance between multiple layers of coils, determined by the thickness of the insulating medium), and magnetic core (optional), which involves introducing a high-permeability material at or around the center of the coil.

[0058] The capacitive-inductive integrated coupling coil provided in this application embodiment offers the most direct and effective means of increasing inductance: the more turns, the greater the inductance. Shorter turn spacing results in more effective turns and greater inductance; within the constraints of layout, reducing turn spacing can increase inductance density per unit area. While conductor cross-sectional area does not primarily determine inductance, it supports the feasibility and efficiency of high-inductance designs. Larger conductor cross-sectional area increases internal inductance and allows for lower resistance, enabling the coil to operate at higher Q values, effectively bringing the effective inductance closer to the theoretical value. Furthermore, in multilayer structures, larger cross-sections support smaller interlayer spacing without short-circuiting, indirectly improving coupling and total inductance. Shortening interlayer spacing allows the equivalent inductance of parallel multilayer coils to approach that of a single layer, enabling control over the inductance of multilayer coils. Increasing the magnetic core is the most efficient means of enhancing inductance, suitable for miniaturized high-inductance requirements. In summary, this application embodiment achieves high freedom, high precision, and high efficiency in inductance design by systematically controlling the number of turns, turn spacing, cross-sectional area, interlayer spacing, and magnetic core usage.

[0059] In an optional embodiment, the lower the resistivity, the larger the cross-sectional area, and the more layers of the positive or negative coil, the higher the current carrying capacity.

[0060] In this embodiment, the positive and negative coils not only function as inductors and capacitors, but also need to operate safely and stably under high frequency and high current. To improve their current-carrying capacity, i.e., the maximum permissible continuous current, the current-carrying capacity of the coils is adjusted by modifying the material, cross-sectional area, and number of layers of the positive and negative coils.

[0061] The capacitive-inductor integrated coupling coil provided in this application improves the upper limit of current carrying capacity by reducing the total AC resistance and enhancing heat dissipation, while suppressing the performance degradation and failure risk caused by Joule heating.

[0062] In an optional embodiment, the higher the dielectric constant and the lower the thickness of the insulating medium, the larger the facing area of ​​the positive coil and the negative coil, and the larger the capacitance of the capacitive-inductive integrated coupling coil.

[0063] In this embodiment, the capacitance can be adjusted by changing the material and thickness of the insulating medium and the area of ​​the positive and negative coils facing each other. The material of the insulating medium determines the dielectric constant, the thickness of the insulating medium is the vertical distance between the positive and negative coils, and the area of ​​the facing coils is the overlapping area of ​​the positive and negative coils in the vertical projection direction.

[0064] The capacitive-inductive integrated coupling coil provided in this application transforms the capacitance from a fixed parasitic parameter into a designable and tunable active functional parameter, thereby achieving precise control of the entire LC resonant system.

[0065] In an optional embodiment, the higher the dielectric constant and the thicker the insulating medium, the higher the withstand voltage rating of the insulating medium.

[0066] In this embodiment, the positive and negative coils are separated by an insulating dielectric layer, forming a distributed capacitance. This capacitor needs to withstand a certain voltage difference during operation. To ensure long-term safe operation, it is essential to prevent electrical breakdown of the dielectric. The voltage rating of the capacitor can be adjusted by changing the material and thickness of the insulating dielectric. The material of the insulating dielectric determines the intrinsic breakdown field strength of the material, and the choice of material directly determines the voltage withstand capability per unit thickness; the thickness is the physical isolation distance between the positive and negative electrodes, and the voltage withstand is directly proportional to the thickness.

[0067] The capacitive-inductive integrated coupling coil provided in this application transforms the withstand voltage capability from a fixed attribute into a designable parameter, thereby adapting to the application requirements of different power levels and safety standards.

[0068] The following is a specific example illustrating the capacitive-inductor integrated coupling coil provided in this application.

[0069] like Figure 6As shown, the coil shape is a planar helical coil, with an inner diameter of... d in When the outer diameter is 20cm, the coil width ω is 1cm, the turn spacing s is 5mm, and the number of turns N is 10, the outer diameter is... d out It is 49cm long and has an average diameter of 49cm. Fill factor .

[0070] Based on the current plate model, the self-inductance of a single coil can be calculated as follows: .

[0071] The capacitance between the two helical coils is estimated below. The distance d between the positive and negative coils is 1 mm, and the insulating medium is polypropylene.

[0072] No. Center radius of the coil ; Calculate the length of the centerline of the total conductor. .

[0073] The overlapping area between the positive and negative coils is ; The approximate capacitance of the parallel plates can be calculated using the following formula: ,in, It is the vacuum dielectric constant, and the dielectric constant of polypropylene. Take 2.2.

[0074] If arranged according to the capacitive-inductive integrated coupling coil method provided in this application, the positive and negative groups can be regarded as being composed of multiple layers of equipotential conductors, and the equivalent capacitance between the two groups is equal to the sum of the parallel capacitances of all cross-group layers: ; Where d is the spacing between single layers, and |ij| is the layer spacing (unit: number of layers), corresponding to the actual distance |ij|d.

[0075] According to the above formula, if 10 layers are stacked, the equivalent capacitance between the positive electrode (layer 1 / 3 / 5 / 7 / 9) and the negative electrode (layer 2 / 4 / 6 / 8 / 10) is about 27.2nF. Increasing the number of layers can further increase the capacitance, and multi-layer parallel connection can increase the current carrying capacity of the coil, thus making it suitable for low-frequency high-current wireless power transmission scenarios.

[0076] It should be noted that the above calculations neglect conductor thickness, potential difference in the conductor distribution, and complex edge distribution (only a flat plate approximation is used); therefore, this is a commonly used upper bound / estimated value in engineering. The error is typically in the range of ±10–15%, depending on the edge field, dielectric inhomogeneity, etc.

[0077] If the actual dielectric is not completely filled (air gap), or the layers are not completely equipotential (the turns are not shorted, and the lead layout causes potential differences), the actual equivalent capacitance will be smaller.

[0078] The fringing field will change the effective A of each layer; for more accurate (±%) results, an edge correction factor can be added or 2.5D / 3D electromagnetic simulation (Momentum / HFSS / Sonnet) or actual measurement can be performed.

[0079] This application also provides a wireless power transmission system, including at least one capacitive-inductive integrated coupling coil as described in any of the above embodiments.

[0080] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A capacitive-inductive integrated coupling coil, characterized in that, It includes multiple layers of insulating medium, multiple layers of positive coils and multiple layers of negative coils, wherein the multiple layers of insulating medium, the multiple layers of positive coils and the multiple layers of negative coils are stacked and arranged alternately in the order of insulating medium, positive coil, insulating medium and negative coil; In this configuration, the positive coils of each layer are connected in parallel, and the negative coils of each layer are connected in parallel.

2. The capacitive-inductive integrated coupling coil according to claim 1, characterized in that, The positive coils are connected to each other by lamination, vias or welding.

3. The capacitive-inductive integrated coupling coil according to claim 1, characterized in that, The negative coils are connected by lamination, vias or welding.

4. The capacitive-inductive integrated coupling coil according to claim 1, characterized in that, The positive coil is connected to the adjacent insulating medium by lamination, spraying or bonding.

5. The capacitive-inductive integrated coupling coil according to claim 1, characterized in that, The insulating medium is made of polyester film, polypropylene film, polyimide or epoxy resin.

6. The capacitive-inductive integrated coupling coil according to any one of claims 1-5, characterized in that, The more turns, the shorter the turn spacing, the larger the cross-sectional area, and the shorter the layer spacing of the positive or negative coil, the greater the inductance of the positive or negative coil.

7. The capacitive-inductive integrated coupling coil according to any one of claims 1-5, characterized in that, The lower the resistivity, the larger the cross-sectional area, and the more layers of the positive or negative coil, the higher the current carrying capacity.

8. The capacitive-inductive integrated coupling coil according to any one of claims 1-5, characterized in that, The higher the dielectric constant and the lower the thickness of the insulating medium, the larger the facing area of ​​the positive and negative coils, and the larger the capacitance of the capacitive-inductive integrated coupling coil.

9. The capacitive-inductive integrated coupling coil according to any one of claims 1-5, characterized in that, The higher the dielectric constant and the greater the thickness of the insulating medium, the higher its withstand voltage rating.

10. A wireless power transmission system comprising at least one capacitive-inductive integrated coupling coil as described in any one of claims 1 to 9.

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