Coupling coil, coupling mechanism and wireless energy transmission system based on Minkowski structure

Abstract

The invention discloses a coupling coil based on a Minkowski structure. The coupling coil comprises a single-turn coupling coil composed of a wire; the single-turn coupling coil starts from the input end of a wire and is arranged according to the novel first-order Minkowski fractal structure profile, the output end of the wire is led out when the wire is arranged for one circle, and the single-turn coupling coil is formed jointly. The novel first-order Minkowski fractal structure contour line is a novel contour line which is formed by the first-order Minkowski fractal structure contour line in the mode that the concave portions of the four square blocks are sunken by the depth of the preset proportion square block side length. The preset proportion is less than 100%; the single-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 Minkowski structure is designed based on the fractal geometry theory, the situation that the mutual inductance and the coupling coefficient of a traditional coupling mechanism are low when the transmission distance is increased and the coupling coil deviates is improved, and the energy transmission efficiency of the wireless power transmission system is improved.

Description

Technical Field

[0001] The present application relates to the field of wireless power transmission technology, and more specifically, to a coupling coil, a coupling mechanism and a wireless power transmission system based on a Minkowski 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 (e.g., rectangular coils), which limits the energy transmission distance and efficiency. In particular, when the transmission distance increases and the coils are offset, the energy transmission efficiency is often greatly reduced. Therefore, it is urgent to optimize the structure of the existing coupling coils 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 Minkowski (Hermann Minkowski, 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 Minkowski structure, comprising: a single-turn coupling coil composed of a wire;

[0007] The single-turn coupling coil starts from the wire input end and is routed according to the outer contour of the novel first-order Minkowski fractal structure. When the wire is followed in one circle, the wire output end is led out to form the single-turn coupling coil.

[0008] The new first-order Minkowski fractal structure outer contour is a new type of outer contour presented by the first-order Minkowski fractal structure outer contour being sunken at the four concave positions by a depth of a preset proportion of the side length of the square; the preset proportion is less than 100%;

[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 preset ratio is 25% to 75%.

[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 Minkowski structure, comprising: a multi-turn coupling coil composed of a conductive wire;

[0017] The outermost circle of the multi-turn coupling coil starts from the wire input end and is wired according to the outer contour of the new first-order Minkowski fractal structure. After following the line for one circle, the wiring continues from the outermost circle inwards according to the outer contour of the new first-order Minkowski fractal structure scaled at a preset equal ratio, and the wiring is gradually carried out circle by circle inwards until the wire output end is led out after following the line for multiple circles, and together constitute the multi-turn coupling coil;

[0018] The new first-order Minkowski fractal structure outer contour line scaled at a preset equal ratio includes four bottom side segments of the new first-order Minkowski fractal structure outer contour line being gradually lengthened circle by circle at a preset first ratio, and other side segments of the new first-order Minkowski fractal structure outer contour line except the bottom side segments of the four concave parts being gradually shortened circle by circle at a preset second ratio;

[0019] The new first-order Minkowski fractal structure outer contour is a new type of outer contour presented by the first-order Minkowski fractal structure outer contour being sunken at the four concave positions by a depth of a preset proportion of the side length of the square; the preset proportion is less than 100%;

[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 preset ratio is 25% to 75%.

[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 a Minkowski structure, wherein a single-turn coupling coil as described in any of the foregoing items is provided at both the transmitting end and the receiving end of the coupling mechanism, or a multi-turn coupling coil as described in any of the foregoing items is provided 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 a Minkowski 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 Minkowski structure based on fractal geometry theory, improves the situation where the mutual inductance and coupling coefficient of a traditional coupling mechanism are low when the transmission distance increases and the coupling coil is offset, and improves 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 diagram of the coupling mechanism provided in the embodiment of the present application;

[0033] Figure 2 A diagram of the step-by-step evolution of the Minkowski fractal structure provided in an embodiment of the present application;

[0034] Figure 3 A curve evolution diagram from the outer contour of the first-order Minkowski fractal structure to the outer contour of the new first-order Minkowski fractal structure provided in the embodiment of the present application;

[0035] Figure 4 A planar structural view of a multi-turn coupled coil based on a Minkowski structure provided in an embodiment of the present application;

[0036] Figure 5 A three-dimensional structural view of a coupling mechanism (coupling device) composed of a multi-turn coupling coil based on a Minkowski structure provided in an embodiment of the present application;

[0037] Figure 6 A schematic diagram of the structure of a wireless energy transmission system based on a Minkowski structure provided in an embodiment of the present application;

[0038] Figure 7 A set of simulation curves showing how the performance of a multi-turn coupling coil based on a Minkowski structure varies with transmission distance provided in an embodiment of the present application;

[0039] Figure 8 A simulation drawing of a multi-turn coupled coil based on a Minkowski structure in an offset state provided in an embodiment of the present application;

[0040] Fig. 9 A set of simulation curves showing how the performance of a multi-turn coupled coil based on a Minkowski structure varies with offset distance provided in an embodiment of the present application;

[0041] Fig.10 The embodiments of the present application provide Figure 4 A planar structural view of a traditional multi-turn rectangular coil whose parameters match those of the multi-turn coupled coil;

[0042] Fig.11 A set of experimental curves showing how the performance of a multi-turn coupling coil based on a Minkowski structure varies with transmission distance provided in an embodiment of the present application;

[0043] Fig.12 A set of experimental curves showing how the performance of a multi-turn coupled coil based on a Minkowski structure varies with offset distance provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] 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.

[0045] 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.

[0046] 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 efficiency, especially when dealing with increased transmission distance and coil offset, the energy transmission efficiency is often greatly reduced. In view of this, the present application provides a coupling coil, coupling mechanism, and wireless energy transmission system based on a Minkowski structure, which are used to improve the energy transmission distance, energy transmission efficiency, and anti-offset capability of the existing WPT system.

[0047] This application first conducts a theoretical analysis and research on the basic structural composition and principles of the coupling coil and coupling mechanism based on the Minkowski 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 the coupling coil and coupling mechanism based on the Minkowski structure compared with the traditional coupling coil and coupling mechanism are analyzed.

[0048] 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.

[0049] 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:

[0050]

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

[0052]

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

[0054]

[0055] In the process of coil design, it should be noted that the coil performance may change with the change of coil size, turn spacing and coil wire diameter. When selecting the operating 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 can be determined s =85kHz.

[0061] Figure 2 This is the step-by-step evolution diagram of the Minkowski fractal structure. The Minkowski fractal structure is a typical fractal geometry structure. The construction process of the Minkowski fractal is to transform a large square ( Figure 2 The 0-order Minkowski fractal structure on the left is divided into nine identical small squares (the nine-square grid division operation), and the five small squares on the two diagonals are retained ( Figure 2 The 1st-order Minkowski fractal structure in the center is composed of five small black-filled squares on the two diagonals shown). Continue to iterate and intercept according to this rule to form Minkowski fractal structures of various orders. For example, Figure 2 The second-order Minkowski fractal structure on the right is based on the first-order Minkowski fractal structure. The five small black-filled squares of the first-order Minkowski fractal structure are divided into nine squares respectively, and the smaller squares on the two diagonals are retained.

[0062] The core characteristics of the Minkowski fractal structure are self-similarity and fractal dimension. For a fractal geometry F, its Hausdorff dimension can be calculated by the following formula:

[0063]

[0064] Among them, n s is the number of self-similar copies under similar changes, r s is the similarity transformation shrinkage ratio.

[0065] According to fractal geometry theory, the Minkowski fractal structure similarity ratio r s is 1 / 3, and the number of copies generated after each iteration is n s =5.

[0066] Therefore, its Hausdorff dimension is:

[0067]

[0068] Based on the above results, it can be judged that the Hausdorff dimension of the Minkowski fractal structure is 1.465, which means that it has good space filling properties. The Minkowski fractal structure has the same growth rate in orthogonal directions and has the same scale factor, and each part is similar to the whole. Due to its isotropy and self-similarity, the Minkowski fractal structure is used in many fields, especially in the design of radar antennas. The radar antenna designed with the Minkowski fractal structure has a higher transmission efficiency.

[0069] refer to Figure 3 An embodiment of the present application provides a coupling coil based on a Minkowski structure, including: a single-turn coupling coil composed of a wire.

[0070] The single-turn coupling coil starts from the wire input end and is routed along the outer contour of the novel first-order Minkowski fractal structure. The wire output end is led out after following the wire for one circle, and together they constitute the single-turn coupling coil of the coupling mechanism for the wireless energy transmission system.

[0071] The novel first-order Minkowski fractal structure outer contour is a novel outer contour presented by the first-order Minkowski fractal structure outer contour being sunken at four concave positions by a depth of a preset proportion of the side length of the square; the preset proportion is less than 100%.

[0072] Figure 3 The five small black filled squares together constitute a first-order Minkowski fractal structure. The outer contour of the first-order Minkowski fractal structure is the outer contour of the first-order Minkowski fractal structure. Figure 3 The outline of the new 1st-order Minkowski fractal structure is a new type of outline (a closed frame composed of green thick solid lines and black thick solid lines) presented by the bottom edges of the 1st-order Minkowski fractal structure at the four concave squares (i.e., the four small squares directly above, directly below, directly to the left, and directly to the right) moving outward by a preset distance (i.e., the bottom edge of the green dotted line moves outward to the black solid line).

[0073] The outer contour of the 1st-order Minkowski fractal structure is slightly recessed at the concave parts of the four blocks (the depth of the recess does not reach the side length of the small block), which constitutes the so-called new 1st-order Minkowski fractal structure outer contour. In fact, a deeper recess will affect the transmission efficiency, while a shallower recess will affect the anti-drift capability. Therefore, after a large number of experiments, it is preferred that the aforementioned preset ratio is between 25% and 75% (i.e., the depth of the recess is 25% to 75% of the side length of the small block) to achieve the maximum comprehensive performance of transmission efficiency and anti-drift capability.

[0074] Figure 3 The wire input and output ends are not drawn in the figure. The key to this application is that the wire is routed in a circle following the outer contour of the so-called new first-order Minkowski fractal structure. There is no strict limitation on which two points on the outer contour of the new first-order Minkowski fractal structure are used to lead out the wire input and output ends.

[0075] Similarly, reference Figure 4 Another embodiment of the present application provides a coupling coil based on a Minkowski structure, including: a multi-turn coupling coil composed of a conductive wire.

[0076] The outermost circle of the multi-turn coupling coil starts from the wire input end and is wired according to the outer contour of the aforementioned new first-order Minkowski fractal structure. After following the line for one circle, the wiring continues from the outermost circle inwardly following the outer contour of the new first-order Minkowski fractal structure scaled at a preset proportional scale, and the wiring is gradually carried out circle by circle inward until the wire output end is led out after following the line for multiple circles, together forming a multi-turn coupling coil for a coupling mechanism of a wireless energy transmission system.

[0077] The new first-order Minkowski fractal structure contour is a new type of contour presented by the first-order Minkowski fractal structure contour being sunken at the four concave parts of the blocks by a depth of a preset proportion of the block side length. The preset proportion is less than 100%, preferably 25% to 75%. Relevant discussions have been made before and will not be repeated here.

[0078] The new first-order Minkowski fractal structure outer contour line scaled at a preset equal ratio includes the bottom edge segments of the four concave parts of the new first-order Minkowski fractal structure outer contour line being gradually lengthened circle by circle at a preset first ratio (reference Figure 4 At the dotted line, the bottom edge segments of the four concave parts are gradually lengthened inwardly), while the other edge segments of the outer contour of the new first-order Minkowski fractal structure, except for the bottom edge segments of the four concave parts, are gradually shortened in a preset second ratio.

[0079] The reason why the outer contour of the new first-order Minkowski fractal structure of the outermost circle is not gradually reduced according to the preset ratio is because the concave part of the outer contour of the new first-order Minkowski fractal structure of the inner circle cannot cover the concave part of the outer contour of the new first-order Minkowski fractal structure of the outer circle, that is, if they are all reduced in equal proportions, a multi-turn structure cannot be formed in engineering. The multi-turn wiring here is a compromise between theoretical calculation and engineering practice. The multi-turn coupling coil is actually a multi-turn mode of an approximate shape formed by further winding the aforementioned single-turn coupling coil inward, and its inventive concept is essentially similar.

[0080] 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.

[0081] The single-turn coupling coil and multi-turn coupling coil of the present application are both composed of a coil wound with a Litz wire with a wire diameter of 2 mm and a rectangular acrylic base plate with a preset wire embedding groove, and the two can be fixed by glue or hoop wire.

[0082] 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 outer contour of the novel 1st-order Minkowski fractal structure), and the direction of the slot is the winding direction of the wire of the aforementioned coupling coil. Then, a hole is drilled at the end of the wire near the center of the acrylic plate, the hole diameter is slightly larger than the wire diameter, for leading out the wire.

[0083] In some embodiments, the specific method for making the aforementioned multi-turn coupling coil includes: making a new type of first-order Minkowski fractal structure outline slightly smaller than a 200mm*200mm square, winding a fixed-length wire (the length of the wire should meet the length of a rectangular inner spiral coil with the same production cost or the same economic benefit) along the outermost contour of the fractal structure, folding the wire inward by about 90° at an appropriate position on the fourth side of the circumscribed square, and then continuing to wind one circle after another along the outermost contour scaled in proportion to the center of the square, repeating this operation until the fixed-length wire is used up, and then connecting another wire at the point where the wire is used up, and leading it out in a direction perpendicular to the plane. Reference Figure 4 , start winding along the outer contour of the new 1st-order Minkowski fractal structure at the wire input end, and continue winding along the contour of the outermost wire inward after winding almost one circle, until the fixed length of wire is exhausted at the wire output end, and then connect another wire at the end of the wire, and lead it out in a direction perpendicular to the plane of the acrylic plate. Put the two final ends of the Litz wire (the aforementioned wire output end and wire input end) into the tin furnace to melt and install the joints for easy connection with other equipment.

[0084] refer to Figure 5 An embodiment of the present application also provides a coupling mechanism based on the Minkowski structure, wherein the single-turn coupling coil described in any of the above items is arranged at 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 the transmitting end and the receiving end of the coupling mechanism. Figure 5 A three-dimensional structural view of a coupling mechanism (coupling device) composed of a multi-turn coupling coil based on a Minkowski structure provided in an embodiment of the present application, Figure 5 It can be seen that the two multi-turn coupled 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 multi-turn coupling coil on one side correspond to the positive and negative poles of the side, and the multi-turn coupling coil on the other side corresponds similarly. The three-dimensional structural view of the coupling mechanism (coupling device) composed of a single-turn coupling coil is not drawn in the attached figure, but it is the same as the coupling mechanism composed of a multi-turn coupling coil, and will not be repeated here.

[0085] An embodiment of the present application further provides a wireless energy transmission system based on the Minkowski structure, wherein the wireless energy transmission system performs wireless energy transmission based on the aforementioned coupling mechanism. Figure 6 The aforementioned coupling mechanism consisting of a single-turn coupling coil or a coupling mechanism consisting of a multi-turn coupling coil is placed here Figure 6 The coupling device, together with other components, constitutes the wireless energy transmission system based on the Minkowski structure.

[0086] Figure 5 It is also a model of a coupling mechanism based on a series-wound Minkowski coil (i.e., a multi-turn coupling coil based on a Minkowski structure with a low density, i.e., a multi-turn coupling coil with a small number of turns wound three or four times) established in the Comsol simulation tool. In this embodiment, the specific size parameters of the model are shown in Table 1 below.

[0087] Table 1 Dimensional parameters of series-wound Minkowski coils

[0088]

[0089] For the series-wound Minkowski coil, this embodiment uses a traditional rectangular coil as a reference object. Given the inherent differences in the shapes of the two types of coils, it is impossible to construct a rectangular coil with completely identical parameters. Therefore, this embodiment adopts a systematic modeling and analysis method, by fixing the area and turn spacing of the coil, and respectively changing the length and number of turns of the rectangular coil, two variables that have a more significant impact on the coupling performance, to construct two traditional rectangular coil models.

[0090] The parameter settings of the three coils are shown in Table 2. The material type, physical field selection, meshing method and research method of each coil are the same. This method aims to provide a comprehensive and reliable comparison benchmark to comprehensively evaluate the performance of fractal coils.

[0091] Table 2 Three coil parameter settings

[0092]

[0093] 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:

[0094]

[0095] First, in this embodiment, the transmission distances of three different types of coils are studied to obtain characteristic curves of their mutual inductance and coupling coefficient as the transmission distance changes. Figure 7 The simulation results shown in (compared to the curves based on real experimental data, the curves obtained by simulation experimental data are smoother) show that the mutual inductance and coupling coefficient of the three coils show a downward trend with the increase of transmission distance, and the rate of decline gradually slows down. When the number of turns is the same, the series-wound Minkowski coil has certain advantages when the transmission distance increases slightly.

[0096] Depend on Figure 7(d) It can be seen that when the transmission distance is less than 3.5cm, the mutual inductance of the series-wound Minkowski coil is higher than that of the rectangular coil I and lower than that of the rectangular coil II; in the transmission distance range of 3.5cm to 20cm, the mutual inductance of the series-wound Minkowski coil is similar to that of the rectangular coil I, while the mutual inductance of the rectangular coil II is always higher than that of the other two coils. This shows that the number of turns of the coil has a significant effect on the mutual inductance. When the number of turns is the same, the series-wound Minkowski coil can maintain a higher mutual inductance when the transmission distance increases. When the coil length is equal, since the structure of the series-wound Minkowski coil has more inflection points, local magnetic field interference will be generated, resulting in its mutual inductance being lower than that of the rectangular coil II.

[0097] Depend on Figure 7 (e) and Figure 7 (f) It can be seen that the coupling coefficient of the series-wound Minkowski coil is always lower than that of the traditional rectangular coil, and its coupling coefficient attenuation rate is always higher than that of the traditional rectangular coil. Analysis shows that this is also because the fractal structure of the series-wound Minkowski coil has more inflection points, which increases the interaction between coils. Due to the inherent characteristics of its structure, the turn spacing changes in the local position, affecting the uniform distribution of the magnetic field, resulting in large fluctuations in the coupling coefficient when the position changes. This feature can bring advantages in certain specific applications, such as when a specific magnetic field distribution is required, but it also brings challenges to application scenarios that require a stable coupling coefficient.

[0098] In summary, when the number of turns is the same, the so-called series-wound Minkowski coil has certain advantages when the transmission distance increases slightly, but its coupling coefficient is relatively low, and the coupling coefficient attenuation rate is also relatively high. In addition, increasing the number of turns of the coil is an important method to improve the coupling coefficient and mutual inductance. In further optimization, improving the coupling effect of the series-wound Minkowski coil should be taken as a research direction. The coupling effect can be improved through methods such as structural optimization and dynamic adjustment design, thereby expanding the application scenarios.

[0099] Then, if Figure 8 As shown, in this embodiment, the anti-offset performance of three different types of coils is studied, and characteristic curves of their mutual inductance and coupling coefficient changing with the offset distance are obtained.

[0100] Depend on Fig. 9(d) It can be seen that when the offset distance is less than 3 cm, the mutual inductance of the series-wound Minkowski coil is higher than that of the rectangular coil I, but lower than that of the rectangular coil II; in the offset distance range of 3 cm to 10 cm, the mutual inductance of the series-wound Minkowski coil is lower than that of the traditional rectangular coil. During the entire offset process, the mutual inductance of the rectangular coil II is always greater than the mutual inductance of the series-wound Minkowski coil and the rectangular coil I. This shows that when the number of turns is the same, the series-wound Minkowski coil can still maintain characteristics that are superior to those of the traditional rectangular coil when the offset distance is small, and once the offset exceeds this threshold, its mutual inductance is lower than that of the traditional rectangular coil.

[0101] Depend on Fig. 9 (e) Fig. 9 (f) It can be seen that the coupling coefficient of the series-wound Minkowski coil is always lower than that of the traditional rectangular coil, and its coupling coefficient attenuation rate is always higher than that of the traditional rectangular coil. The reason is the same as above. The more inflection points of the series-wound Minkowski coil increase the interaction between the coils, affecting the uniform distribution of the magnetic field, resulting in a large fluctuation in the coupling coefficient when the coil is offset.

[0102] Combined with the experimental results, when the number of turns is the same, the series-wound Minkowski coil has certain advantages at smaller offsets, but its coupling coefficient is relatively low, and the coupling coefficient attenuation rate is also relatively high. In addition, increasing the number of turns of the coil is an important method to enhance the anti-offset performance of the coil.

[0103] In summary, the coupling effect of the series-wound Minkowski coil has certain advantages when the transmission distance increases slightly, but when the transmission distance exceeds the threshold, its coupling coefficient is relatively low and the coupling coefficient attenuation rate is relatively high. The series-wound Minkowski coil maintains characteristics that are superior to traditional rectangular coils at small offsets, but when the offset distance exceeds a certain threshold, its mutual inductance value will be lower than the mutual inductance value of traditional rectangular coils. The improvement plan is to increase the number of turns and improve its coupling effect through structural optimization and dynamic parameter adjustment.

[0104] The actual production of the series-wound Minkowski coil shown in Table 1 and the traditional rectangular coil with matching parameters, such as Figure 4 and Fig.10 In this embodiment, the TH2832LCR bridge is used to measure the mutual inductance and self-inductance. Figure 6As shown, the DC power supply outputs DC power at the transmitting end, which is converted into AC power of a specific frequency through a high-frequency inverter module and sent to the primary coupling coil. Based on the principle of electromagnetic induction, the coil converts the current into an alternating electromagnetic field, inducing an AC electromotive force in the secondary coupling coil. The secondary coupling coil at the receiving end captures these electromagnetic fields, and the AC power is rectified into DC power through a high-frequency rectifier module to supply the load.

[0105] 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 series-wound Minkowski coil and the traditional rectangular coil will be compared. The actual experimental data of the transmission distance obtained is as follows Fig.11 As shown in the figure, the actual experimental data of anti-offset performance is as follows Fig.12 shown.

[0106] In the research experiment of the transmission distance of the series-wound Minkowski coil, Fig.11 (a) It can be seen that when the transmission distance is in the range of 3cm to 9cm, the mutual inductance and coupling coefficient of the series-wound Minkowski coil are lower than those of the traditional rectangular coil; when the transmission distance is greater than 9cm, the mutual inductance of the two coils is similar, and the coupling coefficient of the series-wound Minkowski coil is slightly higher than that of the traditional rectangular coil.

[0107] Depend on Fig.11 (b) It can be seen that when the transmission distance changes, the coupling coefficient attenuation rate of the series-wound Minkowski coil is lower, which indicates that the attenuation of its coupling performance is smaller.

[0108] In the anti-deviation research experiment of the series-wound Minkowski coil, Fig.12 (a) It can be seen that when the offset distance is less than 3 cm and greater than 6.5 cm, the mutual inductance and coupling coefficient of the series-wound Minkowski coil are slightly higher than the corresponding values ​​of the rectangular coil, while in other cases, the parameters of the two coils are similar.

[0109] Depend on Fig.12 (b) It can be seen that when the offset distance is less than 4 cm, the coupling coefficient attenuation rate of the series-wound Minkowski coil is lower than that of the traditional rectangular coil; when the offset distance is greater than 4 cm, the parameters of the two coils are similar, which is consistent with the above simulation results.

[0110] It can be seen that the coupling performance of the series-wound Minkowski coil is slightly better than that of the traditional rectangular coil when transmitting over a long distance, and its coupling coefficient attenuation rate is lower. Its coupling performance is better than that of the traditional rectangular coil at small and large offsets, and its performance is slightly worse than that of the rectangular coil at medium offsets. However, as the offset distance increases, its coupling coefficient attenuation rate is always lower than that of the traditional rectangular coil. Therefore, its anti-offset performance is better under certain circumstances and is suitable for specific WPT systems that are prone to offset. This design also shows that tight winding has an important influence on improving the coupling characteristics of the coil.

[0111] This application uses fractal geometry theory and experiments to verify the potential advantages of the Minkowski structure coupling coil in improving coil performance, designs a wireless power transmission system coupling mechanism based on the Minkowski structure, improves the situation where the mutual inductance and coupling coefficient of the traditional coupling mechanism are low when the transmission distance increases and the coupling coil is offset, and improves the energy transmission efficiency of the wireless power transmission system.

[0112] Those skilled in the art will appreciate that the technical features described in the various embodiments and / or claims of the present application may be combined and / or coupled in a variety of ways, even if such combinations and / or couplings 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 coupled in a variety of ways, and all of these combinations and / or couplings fall within the scope of the present application.

[0113] 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 Minkowski structure, characterized in that: include: A single-turn coupled coil consisting of a conductor; The single-turn coupling coil starts from the wire input end and is routed according to the outer contour of the novel first-order Minkowski fractal structure. When the wire is followed in one circle, the wire output end is led out to form the single-turn coupling coil. The new first-order Minkowski fractal structure outer contour is a new type of outer contour presented by the first-order Minkowski fractal structure outer contour being sunken at the four concave positions by a depth of a preset proportion of the side length of the square; The preset ratio is less than 100%; 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 preset ratio is 25% to 75%.

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 Minkowski structure, characterized in that: include: A multi-turn coupled coil consisting of conductive wires; The outermost circle of the multi-turn coupling coil starts from the wire input end and is wired according to the outer contour of the new first-order Minkowski fractal structure. After following the line for one circle, the wiring continues from the outermost circle inwards according to the outer contour of the new first-order Minkowski fractal structure scaled at a preset equal ratio, and the wiring is gradually carried out circle by circle inwards until the wire output end is led out after following the line for multiple circles, and together constitute the multi-turn coupling coil; The new first-order Minkowski fractal structure outer contour line scaled at a preset equal ratio includes four bottom side segments of the new first-order Minkowski fractal structure outer contour line being gradually lengthened circle by circle at a preset first ratio, and other side segments of the new first-order Minkowski fractal structure outer contour line except the bottom side segments of the four concave parts being gradually shortened circle by circle at a preset second ratio; The new first-order Minkowski fractal structure outer contour is a new type of outer contour presented by the first-order Minkowski fractal structure outer contour being sunken at the four concave positions by a depth of a preset proportion of the side length of the square; The preset ratio is less than 100%; 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 preset ratio is 25% to 75%.

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 Minkowski 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 Minkowski 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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