Hilbert structure-based coupling coil, coupling mechanism and wireless energy transfer system

Abstract

The invention discloses a coupling coil based on a Hilbert structure. The coupling coil comprises a multi-turn coupling coil formed by wires; the outermost circle of the multi-turn coupling coil is wired according to a novel second-order Hilbert curve, a plurality of turns of coupling coils are sequentially arranged from the outermost circle to the inside at a preset turn interval, and a wire input end and a wire output end are led out from the same side of an external square of the novel second-order Hilbert curve to form the multi-turn coupling coil; the novel second-order Hilbert curve is an axisymmetric graph, and two axisymmetric objects are half second-order Hilbert curves in the reverse opening direction; the multi-turn coupling coil is used for a coupling mechanism of a wireless energy transfer system. The wireless power transmission system coupling coil based on the Hilbert structure is designed based on the fractal geometry theory, the problem that the mutual inductance and the coupling coefficient of a traditional coupling mechanism are obviously reduced when the coupling coil deviates is solved, the anti-deviation capability of the wireless power transmission system is enhanced, and the energy transmission efficiency of the wireless power transmission system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of wireless power transmission, and more specifically, to a coupling coil, a coupling mechanism and a wireless power transmission system based on a Hilbert structure. Background Art

[0002] Wireless Power Transmission (WPT) technology has been increasingly widely used in fields such as electric vehicles, smart electronic devices and implantable medical devices, and has good development prospects.

[0003] The coupling mechanism is an extremely important component of the WPT system (wireless power transmission system or wireless energy transmission system), which realizes the wireless transmission and reception of energy. With the rapid development of WPT technology, the design requirements for the coupling mechanism are becoming higher and higher. The research on the coupling mechanism can be divided into three aspects: transmission coil structure, compensation network structure and electromagnetic shielding structure. Among them, the transmission coil has the most significant impact on the transmission performance of the coupling mechanism.

[0004] However, traditional coupling mechanisms often use simple coil designs, which limits the energy transmission distance and efficiency, especially when dealing with increased transmission distance and coil offset. Therefore, it is urgent to optimize the structure of the existing coupling coil to improve the energy transmission distance, energy transmission efficiency and anti-offset capability of the WPT system. Summary of the invention

[0005] In response to at least one defect or improvement need in the prior art, the present application provides a coupling coil, a coupling mechanism and a wireless energy transmission system based on the Hilbert (David Hilbert, a famous German mathematician) structure, which is used to improve the energy transmission distance, energy transmission efficiency and anti-deviation capability of the existing WPT system.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present application provides a coupling coil based on a Hilbert structure, comprising: a single-turn coupling coil composed of a wire;

[0007] The wire is laid out according to the novel second-order Hilbert curve, and the wire input end and the wire output end are led out on the same side of the circumscribed square of the novel second-order Hilbert curve to form the single-turn coupling coil;

[0008] The novel second-order Hilbert curve is an axisymmetric figure, and both axisymmetric objects are semi-second-order Hilbert curves in the opposite opening direction;

[0009] The single-turn coupling coil is used as a coupling mechanism of a wireless energy transmission system.

[0010] Furthermore, it also includes: a carrying mechanism for carrying the single-turn coupling coil;

[0011] A wire embedding groove is pre-set on one surface of the bearing mechanism;

[0012] The groove direction of the wire embedding groove follows the wire direction of the single-turn coupling coil;

[0013] The single-turn coupling coil is fixed to the wire embedding groove by clamping or gluing.

[0014] Furthermore, the conductive wire is a Litz wire.

[0015] Furthermore, the ends of the wire input end and the wire output end are both provided with connectors.

[0016] In a second aspect, the present application provides a coupling coil based on a Hilbert structure, comprising: a multi-turn coupling coil composed of a conductive wire;

[0017] The outermost turn of the multi-turn coupling coil is laid out according to the new second-order Hilbert curve, and then, a plurality of turns of coupling coils are arranged in sequence from the outermost turn to the inside with a preset turn spacing.

[0018] Lead out a wire input end and a wire output end on the same side of the circumscribed square of the novel second-order Hilbert curve to form the multi-turn coupling coil;

[0019] The novel second-order Hilbert curve is an axisymmetric figure, and both axisymmetric objects are semi-second-order Hilbert curves in the opposite opening direction;

[0020] The multi-turn coupling coil is used as a coupling mechanism of a wireless energy transmission system.

[0021] Furthermore, it also includes: a carrying mechanism for carrying the multi-turn coupling coil;

[0022] A wire embedding groove is pre-set on one surface of the bearing mechanism;

[0023] The groove direction of the wire embedding groove follows the direction of the wire of the multi-turn coupling coil;

[0024] The multi-turn coupling coil is fixed to the wire embedding groove by clamping or gluing.

[0025] Furthermore, the conductive wire is a Litz wire.

[0026] Furthermore, the ends of the wire input end and the wire output end are both provided with connectors.

[0027] In a third aspect, the present application provides a coupling mechanism based on the Hilbert structure, wherein the single-turn coupling coil described in any of the above items is arranged at both the transmitting end and the receiving end of the coupling mechanism, or the multi-turn coupling coil described in any of the above items is arranged at both the transmitting end and the receiving end of the coupling mechanism.

[0028] In a fourth aspect, the present application provides a wireless energy transmission system based on the Hilbert structure, wherein the wireless energy transmission system performs wireless energy transmission based on the aforementioned coupling mechanism.

[0029] In general, the above technical solutions conceived by the present application can achieve the following beneficial effects compared with the prior art:

[0030] The present application designs a coupling coil of a wireless power transmission system based on a Hilbert structure based on fractal geometry theory, improves the problem of a significant decrease in mutual inductance and coupling coefficient of a traditional coupling mechanism when the coupling coil is offset, enhances the anti-offset capability of the wireless power transmission system, and is beneficial to improving the energy transmission efficiency of the wireless power transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 An equivalent model of the coupling mechanism provided in the embodiment of the present application;

[0033] Figure 2 A diagram showing the evolution of the Hilbert curve structure provided in the embodiment of the present application;

[0034] Figure 3 The Hilbert curve of each order provided in the embodiment of the present application;

[0035] Figure 4 A construction segmentation diagram of a semi-second-order Hilbert curve in the reverse opening direction provided in an embodiment of the present application;

[0036] Figure 5 A planar structural view of a series-wound Hilbert coil (single-turn coupled coil) provided in an embodiment of the present application;

[0037] Figure 6 A planar structural view of a densely wound Hilbert coil (multi-turn coupled coil) provided in an embodiment of the present application;

[0038] Figure 7A three-dimensional structural view of a coupling mechanism (coupling device) composed of a series-wound Hilbert coil provided in an embodiment of the present application;

[0039] Figure 8 A schematic diagram of the structure of a wireless energy transmission system provided in an embodiment of the present application;

[0040] Fig. 9 A set of simulation curves showing the performance of the series-wound Hilbert coil provided in the embodiment of the present application as the transmission distance and the offset distance increase;

[0041] Fig.10 A simulation diagram of a series-wound Hilbert coil provided in an embodiment of the present application;

[0042] Fig.11 A set of experimental curves showing the performance of the densely wound Hilbert coil provided in the embodiments of the present application as the transmission distance and the offset distance increase. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0044] The terms "including" or "having" and any variations thereof in the specification, claims or drawings of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device including 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 these processes, methods, products or devices.

[0045] As described in the background technology section of the specification, traditional coupling mechanisms often use simple coil designs (e.g., rectangular coils), which limits the energy transmission distance and transmission efficiency, especially when dealing with increased transmission distance and coil offset, the transmission efficiency is often greatly reduced. In view of this, the present application proposes a coupling coil, coupling mechanism, and wireless energy transmission system based on a Hilbert structure, which is used to improve the energy transmission distance, energy transmission efficiency, and anti-offset capability of the existing WPT system.

[0046] This application first conducts a theoretical analysis and research on the basic structural composition and principles of coupling coils and coupling mechanisms based on the Hilbert structure; secondly, the model is constructed in the Comsol multi-physics field finite element tool and verified through experiments; finally, the experimental conclusions are summarized, and the advantages and application scenarios of coupling coils and coupling mechanisms based on the Hilbert structure are analyzed compared with traditional coupling coils and coupling mechanisms.

[0047] like Figure 1 The figure shows the equivalent model diagram of the coupling mechanism of the wireless power transmission system. Figure 1 As can be seen from the figure, the coupling mechanism of the wireless power transmission system consists of two basic parts: the power transmitter ( Figure 1 Left side) and power receiving end ( Figure 1 right side). is the magnetic flux of the primary and secondary coils in the magnetic core; It is the leakage flux generated by the primary and secondary coils; is the equivalent magnetic flux after the primary and secondary coil turns are linked; L1, L2, and M are the primary self-inductance, secondary self-inductance, and the mutual inductance of the two respectively; the number of turns on both sides is recorded as N1 and N2 respectively.

[0048] Establish Figure 1 The mutual inductance model of the wireless power transmission system shown in the figure, where the primary voltage u1 and the secondary voltage u2 can be expressed as:

[0049]

[0050]

[0051] Therefore, the mutual inductance can be expressed as:

[0052]

[0053] In subsequent experimental studies, the embodiment of the present application uses the coupling coefficient k to characterize the magnetic coupling performance of the Hilbert structure coupling coil and the traditional coil:

[0054]

[0055] In the process of coil design, it should be noted that the coil performance will change with the change of coil size, turn spacing and coil wire diameter. When selecting the working frequency for experimental research, it is necessary to pay special attention to these parameters. The coil resistance R can be obtained by calculation:

[0056]

[0057] The self-inductance of the coil can also be approximately calculated by the following formula:

[0058]

[0059] Where ρ represents the resistivity of the wire, r represents the radius of the wire, l represents the length of the coil, A represents the cross-sectional area of ​​the wire, μ0 represents the magnetic permeability of the vacuum, and μ r represents the relative magnetic permeability of the coil material, l represents the average length of the coil, and N represents the number of turns.

[0060] According to the above formula, combined with the actual equipment of the experimental platform, the operating frequency f of the experimental system is determined s =85kHz.

[0061] Figure 2 This is the construction evolution diagram of the Hilbert curve. German mathematician David Hilbert discovered such a fractal curve that can fill the entire unit square. He called it the Hilbert curve. The construction evolution process of this Hilbert curve is as follows. First, divide a square into 4 small squares, then start from the small square in the lower left corner, draw a line through all the small squares, and finally reach the lower right corner. Now, divide this square into 16 small squares, and the goal is also to traverse all the small square grids from the lower left corner and finally reach the lower right corner. Before this, a traversal method for 2x2 squares has been obtained, which can be used at this time. Put the two 2x2 grids intact in the upper two rows, rotate them 90 degrees to the right and put them in the lower left, rotate them 90 degrees to the left and put them in the lower right, and then add three line segments to connect them. Now we have a method to traverse the 4x4 square from the lower left to the lower right, which can be used in larger-scale graphics. By using the method just mentioned to put four 4x4 squares into an 8x8 square, we get a curve that passes through all 64 small squares. By doing this continuously, after infinite iterations, each square becomes infinitely small, and the final continuous graph will obviously pass through all the small square grids. This final continuous graph is the so-called Hilbert curve.

[0062] Figure 3 is a Hilbert curve of each order. The Hilbert curve has a loose self-similar property: the 0th-order Hilbert curve is a "semi-ring" structure with a square outline. Let its side length be b. The 1st-order Hilbert curve uses the structure of the 0th-order Hilbert curve to fill each edge, thus forming a "semi-ring" structure on each edge. Figure 3 It can be seen that the contour area of ​​the 1st, 2nd, 3rd, ..., nth order Hilbert curve is exactly the same as that of the 0th order, that is, no matter how many times it is iterated, the contour area of ​​the Hilbert curve remains unchanged and there are always only two endpoints.

[0063] The Hilbert curve is a typical fractal geometry structure, and its core features are self-similarity and fractal dimension. For a fractal geometry F, its Hausdorff dimension can be calculated by the following formula:

[0064]

[0065] Among them, n s is the number of self-similar copies under similar changes, r s is the similarity transformation shrinkage ratio.

[0066] According to fractal geometry theory, the similarity ratio of Hilbert fractal (Hilbert curve) is r s 1 / 2, and the number of copies generated after each iteration is n s =4, the Hilbert curve with an initial perimeter of s can theoretically approach infinity after n iterations, but its area is convergent and will fill the entire square area.

[0067] Therefore, its Hausdorff dimension is:

[0068]

[0069] Based on the above results, we can conclude that the Hausdorff dimension of the Hilbert curve is 2, which means that it will exhibit two-dimensional characteristics when filling space. The Hilbert curve can fill the entire two-dimensional plane in a continuous and non-differentiable way, and its fractal dimension reflects its filling pattern on the two-dimensional plane and how it exhibits infinite length in a finite space through an infinite iterative process.

[0070] refer to Figure 5 An embodiment of the present application provides a coupling coil based on a Hilbert structure, which includes: a single-turn coupling coil composed of a wire.

[0071] The wires are laid out according to the new second-order Hilbert curve. The wire input and output ends are led out on the same side of the circumscribed square of the new second-order Hilbert curve to form a single-turn coupling coil. Figure 5 The two wire ends lead out from the left side. The single-turn coupling coil is used as the coupling mechanism of the wireless energy transmission system.

[0072] The new second-order Hilbert curve is an axisymmetric graph. Both axisymmetric objects are semi-second-order Hilbert curves in the opposite opening direction. Figure 4 . Figure 4In fact, it is a 2nd order Hilbert curve, which opens downward, and the half in the opposite direction of opening is the so-called half-2nd order Hilbert curve in the opposite direction of opening. The so-called new 2nd order Hilbert curve of the present application is composed of two half-2nd order Hilbert curves in the opposite direction of opening that are axially symmetric.

[0073] Similarly, reference Figure 6 Another embodiment of the present application provides a coupling coil based on the Hilbert structure, including: a multi-turn coupling coil composed of a conductive wire.

[0074] The outermost turn of the multi-turn coupling coil is laid out according to the aforementioned new second-order Hilbert curve. Then, a plurality of turns of coupling coils are arranged inwards from the outermost turn with a preset turn spacing. Similarly, the wire input end and the wire output end are led out on the same side of the circumscribed square of the new second-order Hilbert curve to form a multi-turn coupling coil. Figure 6 The two wire ends leading out from the left side are one in the outermost layer and one in the innermost layer. The multi-turn coupling coil is also used as a coupling mechanism for wireless energy transmission systems. The multi-turn coupling coil is actually a multi-turn mode of the same shape formed by further winding the single-turn coupling coil inwards, and the inventive concept is essentially the same.

[0075] In some embodiments, the conductor is a Litz wire. Litz wire is a conductor made of multiple independently insulated conductors twisted or braided. This structure allows the electromagnetic field to be evenly distributed, thereby reducing the effects of skin effect and proximity effect on current distribution. Litz wire is widely used in high-frequency inductors, transformers, inverters, fuel cells, motors, communications, IT equipment and other occasions due to its good flexibility and high-frequency performance.

[0076] The single-turn coupling coil and multi-turn coupling coil of the present application are both composed of a novel second-order Hilbert curve fractal coil wound with Litz wire of 2 mm in diameter and a rectangular acrylic base plate with a preset wire embedding groove, which can be fixed with glue or hoop wire.

[0077] A slot is made on a 200mm*200mm acrylic plate, the cross section of the slot is the circumscribed square of the cross section of the aforementioned Litz wire (i.e. the circumscribed square of the novel second-order Hilbert curve), and the direction of the slot is the winding direction of the conductor of the aforementioned coupling coil.

[0078] In some embodiments, the specific manufacturing method of the single-turn coupling coil and the multi-turn coupling coil includes: dividing a 200mm*200mm square into 49 small squares, selecting 9 small squares near a corner as a basic unit, and filling the entire basic unit with a wire according to a new second-order Hilbert curve fractal winding method. The four basic units at the four corners are all wound in this way and are symmetrical about the two midlines of the square to form four basic units, and the basic units are connected in series with wires to form a wire output end and a wire input end on the same side of the square. The lead-in end and the lead-out end of the corresponding basic unit on each horizontal line or vertical line are directly connected through Litz wire. The two final ends of the Litz wire (the aforementioned wire output end and wire input end) are placed in a tin furnace for melting and joints are installed to facilitate connection with other equipment.

[0079] An embodiment of the present application further provides a coupling mechanism based on the Hilbert structure, wherein the single-turn coupling coil described in any of the above items is arranged at both the transmitting end and the receiving end of the coupling mechanism, or the multi-turn coupling coil described in any of the above items is arranged at both the transmitting end and the receiving end of the coupling mechanism. Figure 7 A three-dimensional structural view of a coupling mechanism (coupling device) composed of a series-wound Hilbert coil (single-turn coupling coil) provided in an embodiment of the present application, comprising Figure 7 It can be seen that the two series-wound Hilbert coils are placed opposite to each other and are equivalent to Figure 1 The equivalent model of the coupling mechanism is shown in Figure 2. Figure 1 In the figure, the wire input end and the wire output end of the series-wound Hilbert coil on one side correspond to the positive and negative poles on that side, and the series-wound Hilbert coil on the other side corresponds to the positive and negative poles on that side. The three-dimensional structural view of the coupling mechanism (coupling device) composed of the densely wound Hilbert coil (multi-turn coupling coil) is not drawn in the attached figure, but it is the same as the coupling mechanism composed of the series-wound Hilbert coil, and will not be repeated here.

[0080] An embodiment of the present application further provides a wireless energy transmission system based on the Hilbert structure, wherein the wireless energy transmission system performs wireless energy transmission based on the aforementioned coupling mechanism. Figure 8 The aforementioned coupling mechanism consisting of a series-wound Hilbert coil or a coupling mechanism consisting of a closely-wound Hilbert coil is placed here Figure 8 The coupling device, together with other components, constitutes the wireless energy transmission system based on the Hilbert structure.

[0081] Figure 5 and Figure 7 This is a model of a series-wound Hilbert coil and a corresponding coupling mechanism established in the Comsol simulation tool. In this embodiment, specific size parameters of the model are shown in Table 1 below.

[0082] Table 1 Dimensional parameters of series-wound Hilbert coils

[0083]

[0084]

[0085] For the series-wound Hilbert coil, the present embodiment uses a traditional rectangular coil as a reference object. Based on the characteristics of the series-wound Hilbert coil, the present embodiment establishes a traditional inner spiral rectangular coil whose parameters match the Hilbert coil. This method compares the performance difference of the two coils in the same space and with the same consumables (i.e., cost).

[0086] The parameter settings of the traditional rectangular coil are shown in Table 2. The material type, physical field selection, meshing method and research method are all the same as those of the series-wound Hilbert coil. Through this method, this embodiment aims to provide a relatively reasonable comparison method that fits engineering practice, so as to evaluate the performance of the fractal coil.

[0087] Table 2 Two coil parameter settings

[0088]

[0089] The coupling coefficient attenuation rate is defined as the ratio of the difference between the initial coupling coefficient and the current coupling coefficient to the initial coupling coefficient after the coil position changes. The expression is:

[0090]

[0091] First, in this embodiment, the transmission distances of different types of coils are studied to obtain characteristic curves of their mutual inductance and coupling coefficient as the transmission distance and offset distance change. Fig. 9 A set of simulation curves showing the performance of the series-wound Hilbert coil provided in the embodiment of the present application as the transmission distance and the offset distance increase. Fig.10 A set of simulation diagrams of a series-wound Hilbert coil provided in an embodiment of the present application.

[0092] The research results on transmission distance show that the mutual inductance and coupling coefficient of the series-wound Hilbert coil are significantly lower than those of the traditional rectangular coil at different transmission distances, and the degree of coupling coefficient attenuation is also higher. Fig.10 (a) with Fig.10 (b) It can be seen that although the spatial filling rate of the Hilbert curve is high, the edges of its units are arranged orthogonally. This arrangement has a greater disturbance on the magnetic field distribution, thereby reducing the magnetic flux density of the coil, reducing the mutual inductance between the primary and secondary sides, and ultimately resulting in a lower coupling coefficient.

[0093] In summary, the mutual inductance and coupling coefficient of the series-wound Hilbert coil are poor when the transmission distance increases, and the attenuation rate of the coupling coefficient is relatively high. This shows that not every fractal geometry is suitable for the WPT system. When designing the coupling coil, it is necessary to consider both the optimization of the physical parameters and the inherent characteristics of the magnetic field of the coupling coil, reduce the cross-cancellation of the magnetic field, thereby reducing the magnetic field disturbance and making the magnetic field distribution more uniform. Although the optimization effect of the series-wound Hilbert coil on the transmission distance is poor, it still has important guiding significance for optimizing the fractal coil designed with the "Hilbert curve" structure, and it still has application prospects under certain conditions.

[0094] The results of the study on the offset distance show that the mutual inductance and coupling coefficient of the two coils decrease with the increase of the offset distance. Fig. 9 (d) It can be seen that when the offset distance is less than 7 cm, the coupling coefficient attenuation rate of the series-wound Hilbert coil is higher than that of the traditional rectangular coil. It is worth noting that when the offset distance is between 4.5 cm and 6.5 cm, the coupling coefficient attenuation rate of the series-wound Hilbert coil is almost unchanged, which shows that it has a high degree of retention of the coupling coefficient in the case of medium-distance offset. In the offset distance range of 7 cm to 10 cm, the coupling coefficient attenuation rate of the series-wound Hilbert coil begins to gradually decrease than that of the traditional rectangular coil.

[0095] The analysis shows that although the coupling coefficient of the series-wound Hilbert coil is low, it can maintain a stable coupling coefficient when the offset is medium, has a good anti-offset effect, and maintains a better coupling coefficient attenuation rate than the traditional rectangular coil when the offset distance is large. This is due to the special fractal structure of the series-wound Hilbert coil. Its self-similarity ensures the full range coupling of the primary and secondary coils, enhances the uniformity of the magnetic field, and ensures that it can maintain a stable coupling coefficient, which is very meaningful for systems that are sensitive to offsets. Therefore, the series-wound Hilbert coil optimizes the anti-offset performance of the coil. In order to obtain a coupling mechanism with more practical significance and value, the densely wound Hilbert fractal is used for experimental research.

[0096] The series-wound Hilbert coils and traditional rectangular coils with matching parameters were made as shown in Tables 1 and 2, and the mutual inductance and self-inductance were measured using a TH2832 LCR bridge. Figure 8The transmitting end of the wireless power transmission system outputs direct current from a direct current power supply, which is converted into alternating current of a specific frequency by a high-frequency inverter module and sent to the primary coupling coil. The coil converts the current into an alternating electromagnetic field based on the principle of electromagnetic induction, and induces an alternating electromotive force in the secondary coupling coil. The secondary coupling coil at the receiving end captures these electromagnetic fields, and the alternating current is rectified into direct current through a high-frequency rectifier module and supplied to the load.

[0097] In this embodiment, after the measurement is completed, the mutual inductance, coupling coefficient and attenuation rate between the coils are first calculated. Then, the data are grouped and a curve chart is drawn to visually observe the change trend of each parameter. Next, the performance difference between the fractal coil and the traditional coil will be compared.

[0098] For the second set of experiments, that is, the control experiment of the densely wound Hilbert coil (multi-turn coupled coil), Fig.11 (a) It can be seen that after increasing the number of coil turns and optimizing the tight winding, the mutual inductance and coupling coefficient of the tightly wound Hilbert coil are very similar to those of the rectangular coil. When tightly wound, the mutual inductance and coupling coefficient of the coil are both higher, which shows that tight winding plays an important role in improving the coupling performance of the coil.

[0099] Depend on Fig.11 (b) It can be seen that the coupling coefficient attenuation rates of the two coils are also similar. When the transmission distance is in the range of 8cm to 11cm, the coupling coefficient attenuation rate of the densely wound Hilbert coil is slightly higher than that of the rectangular coil. Although the parameters of the two coils are similar, the densely wound Hilbert coil has a shorter wire length and uses less copper, so it still has certain advantages.

[0100] For the second set of experiments, that is, the control experiment of the densely wound Hilbert coil, Fig.11 (c) It can be seen that as the offset distance increases, the mutual inductance of the densely wound Hilbert coil is always higher than that of the rectangular coil, and this advantage is more obvious when the offset distance is greater than 6 cm. When the offset distance is less than 3.5 cm and greater than 7.5 cm, the coupling coefficients of the two coils are similar; when the offset distance is in the range of 3.5 cm to 7.5 cm, the coupling coefficient of the densely wound Hilbert coil is significantly higher than that of the rectangular coil.

[0101] Depend on Fig.11 (d) It can be seen that when the offset distance is in the range of 3.5 cm to 7 cm, the coupling coefficient attenuation rate of the densely wound Hilbert coil is significantly lower than that of the rectangular coil, which indicates that its anti-offset performance is better, which is consistent with the simulation results.

[0102] In summary, after tight winding, the performance is similar to that of the traditional rectangular coil, but the copper content is less, so its transmission performance is optimized to a certain extent. When the mid-distance offset occurs, that is, the offset distance is about half of the coil size, the coupling coefficient attenuation rate is low, and it has good anti-offset performance, which is suitable for WPT systems that are sensitive to offset. This design also shows that tight winding has an important influence on improving the coupling characteristics of the coil.

[0103] Those skilled in the art will appreciate that the features described in the various embodiments and / or claims of the present application may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present application. In particular, without departing from the spirit and teachings of the present application, the technical features described in the various embodiments and / or claims of the present application may be combined and / or combined in a variety of ways, and all of these combinations and / or combinations fall within the scope of the present application.

[0104] Although the present application has been shown and described with reference to specific exemplary embodiments of the present application, it should be understood by those skilled in the art that various changes in form and details may be made to the present application without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents. Therefore, the scope of the present application should not be limited to the above-mentioned embodiments, but should be determined not only by the appended claims, but also by the equivalents of the appended claims.

Claims

1. A coupling coil based on a Hilbert structure, characterized in that: include: A single-turn coupled coil consisting of a conductor; The wire is laid out according to the novel second-order Hilbert curve, and the wire input end and the wire output end are led out on the same side of the circumscribed square of the novel second-order Hilbert curve to form the single-turn coupling coil; The novel second-order Hilbert curve is an axisymmetric figure, and both axisymmetric objects are semi-second-order Hilbert curves in the opposite opening direction; The single-turn coupling coil is used as a coupling mechanism of a wireless energy transmission system.

2. The coupling coil according to claim 1, characterized in that: It also includes: a carrying mechanism for carrying the single-turn coupling coil; A wire embedding groove is pre-set on one surface of the bearing mechanism; The groove direction of the wire embedding groove follows the wire direction of the single-turn coupling coil; The single-turn coupling coil is fixed to the wire embedding groove by clamping or gluing.

3. The coupling coil according to claim 1, characterized in that: The conductor is a Litz wire.

4. The coupling coil according to claim 1, characterized in that: The ends of the wire input end and the wire output end are both provided with connectors.

5. A coupling coil based on a Hilbert structure, characterized in that: include: A multi-turn coupled coil consisting of conductive wires; The outermost turn of the multi-turn coupling coil is wired according to the novel second-order Hilbert curve, and then, a plurality of turns of coupling coils are arranged inward from the outermost turn with a preset turn spacing, and a wire input end and a wire output end are led out on the same side of the circumscribed square of the novel second-order Hilbert curve to form the multi-turn coupling coil; The novel second-order Hilbert curve is an axisymmetric figure, and both axisymmetric objects are semi-second-order Hilbert curves in the opposite opening direction; The multi-turn coupling coil is used as a coupling mechanism of a wireless energy transmission system.

6. The coupling coil according to claim 5, characterized in that: It also includes: a carrying mechanism for carrying the multi-turn coupling coil; A wire embedding groove is pre-set on one surface of the bearing mechanism; The groove direction of the wire embedding groove follows the direction of the wire of the multi-turn coupling coil; The multi-turn coupling coil is fixed to the wire embedding groove by clamping or gluing.

7. The coupling coil according to claim 5, characterized in that: The conductor is a Litz wire.

8. The coupling coil according to claim 5, characterized in that: The ends of the wire input end and the wire output end are both provided with connectors.

9. A coupling mechanism based on a Hilbert structure, characterized in that: The single-turn coupling coil according to any one of claims 1 to 4 is provided at both the transmitting end and the receiving end of the coupling mechanism, or the multi-turn coupling coil according to any one of claims 5 to 8 is provided at both the transmitting end and the receiving end of the coupling mechanism.

10. A wireless energy transmission system based on Hilbert structure, characterized in that: The wireless energy transmission system performs wireless energy transmission based on the coupling mechanism described in claim 9.

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