Coil winding structure, coil winding method and transformer

Abstract

The present invention discloses a coil winding structure, a coil winding method, and a transformer, belonging to the field of wireless charging technology. The coil winding structure includes a large coil with n turns wound by a wire, where n is a natural number. The large coil includes four partitions, and the four partitions include a target partition. The number of turns of the target partition satisfies at least one of the following conditions: when the target partition is the partition with the smallest mutual inductance value among the four partitions, the coil winding structure also includes a small coil connected to the n-turn large coil, the small coil is located within the target partition, the total number of turns of the coil winding structure is #imgabs0# turns, and the number of turns of the target partition is n+1 turns; or when the target partition is the partition with the largest mutual inductance value among the four partitions, the total number of turns of the coil winding structure is #imgabs1# turns, and the number of turns of the target partition is n-1 turns. The present invention solves the problem of offset inconsistency in transformers in the prior art, achieving the effect of reducing the difference in mutual inductance between the various partitions.

Description

Technical Field

[0001] The present invention relates to the field of wireless charging technology, and in particular to a coil winding structure, a coil winding method and a transformer. Background Art

[0002] The coil winding structures commonly used for the primary coil and secondary coil of the loosely coupled transformer in the existing wireless charging system are as follows: Figure 1 As shown, the problem with this coil winding structure is that when the secondary coil is offset by the same distance from the primary coil in different directions, there is a large difference in the mutual inductance value of the transformer. This transformer offset inconsistency is usually manifested in that the mutual inductance value when offset to a certain direction is significantly lower than the mutual inductance value when offset to other directions. This brings difficulties to the design and control of the wireless charging system, and it is impossible to achieve a current-sharing state, which is likely to affect the function and performance of the wireless charging system. Summary of the Invention

[0003] The main purpose of the present invention is to provide a coil winding structure, a coil winding method and a transformer, aiming to solve the technical problem of offset inconsistency in the transformer in the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a coil winding structure, which is applied to a coil, wherein the coil is wound on a magnetic sheet, and the coil winding structure comprises:

[0006] A large coil of n turns wound by a wire, wherein n is a natural number, includes four partitions, the four partitions include a target partition, and the number of turns of the target partition satisfies at least one of the following conditions:

[0007] When the target partition is the partition with the smallest mutual inductance value among the four partitions, the coil winding structure further includes a small coil connected to the n-turn large coil, and the small coil is located in the target partition. The total number of turns of the coil winding structure is turns, the number of turns of the target partition is n+1 turns; or,

[0008] When the target partition is the partition with the largest mutual inductance value among the four partitions, the total number of turns of the coil winding structure is The number of turns of the target partition is n-1 turns.

[0009] Optionally, in the above coil winding structure, the large coil includes:

[0010] A first lead-out terminal located on the inner side;

[0011] A winding portion wound from inside to outside, the winding portion including n turns of winding;

[0012] A second lead-out terminal located on the outside;

[0013] The first lead-out end is arranged at the starting point of the first winding circle, and the second lead-out end is arranged at the ending point of the nth winding circle.

[0014] Optionally, in the above coil winding structure, the small coil includes:

[0015] An outer winding conductor portion and a bent conductor portion connected in sequence;

[0016] The position and length of the bent wire portion are adjustable within the target partition to adjust the winding area of the small coil.

[0017] Optionally, in the above coil winding structure, when the target partition is the first partition, the small coil further includes a third lead-out end;

[0018] The outer winding wire portion is connected to the second lead-out end and is located outside the n-th winding turn of the first partition; the bent wire portion is connected to the third lead-out end, and the third lead-out end and the first lead-out end are led out in the same direction;

[0019] The first partition is a quadrant area where the second lead-out end is located in a coordinate system established with the center of the large coil as the origin.

[0020] Optionally, in the above coil winding structure, when the target partition is the second partition, the small coil further includes a first connecting end and a second connecting end;

[0021] The first connection end is connected to the outer winding wire portion and is disposed on the mth winding wire of the second partition, and the outer winding wire portion is located between the m-1th winding wire and the mth winding wire of the large coil, where m≤n, and m is a natural number;

[0022] One end of the second connection end is connected to the bent wire portion, is disposed on the (m+1)th winding of the second partition and is located outside the first connection end, and the other end is connected to the (m)th winding of the large coil;

[0023] The second lead-out end and the first lead-out end are led out in the same direction;

[0024] The second partition is any quadrant area outside the first partition in a coordinate system established with the center of the large coil as the origin.

[0025] Optionally, in the above coil winding structure, the position of the conductor of the bent conductor portion is adjustable in the x-direction and / or y-direction of a coordinate system established with the center of the large coil as the origin.

[0026] Optionally, in the above coil winding structure, the wire is a multi-strand wire.

[0027] In a second aspect, the present invention further provides a coil winding method of the coil winding structure as described above, the method comprising:

[0028] A large coil with n turns of wire is wound on the magnetic sheet, where n is a natural number;

[0029] Based on the four partitions of the large coil, determining a target partition, wherein the target partition is a partition with the smallest mutual inductance value or a partition with the largest mutual inductance value among the four partitions;

[0030] When the target partition is the partition with the smallest mutual inductance value among the four partitions, a small coil is wound in the target partition so that the number of turns of the target partition is n+1 turns, and the total number of turns of the coil winding structure is turns, wherein the small coil is connected to the n-turn large coil; or,

[0031] When the target partition is the partition with the largest mutual inductance value among the four partitions, within the target partition, subtract The number of turns of the coil is n-1, so that the number of turns of the target partition is n-1. The total number of turns of the coil winding structure is Turn.

[0032] In a third aspect, the present invention further provides a transformer, comprising:

[0033] A magnetic sheet, and a coil wound on the magnetic sheet;

[0034] The coil adopts the coil winding structure as described above.

[0035] Optionally, in the above transformer, the coil includes:

[0036] Primary coil and secondary coil;

[0037] The primary coil adopts the coil winding structure, and / or

[0038] The secondary coil adopts the coil winding structure.

[0039] The above one or more technical solutions provided by the present invention may have the following advantages or at least achieve the following technical effects:

[0040] The present invention proposes a coil winding structure, a coil winding method, and a transformer. A small coil is connected to a large coil of n turns wound with a wire, and the small coil is located in the partition with the smallest mutual inductance among the four partitions of the large coil, so that the number of coil turns in the target partition is one more turn than the number of coil turns in other partitions of the large coil, thereby improving the mutual inductance value of the target partition. The large coil can also be reduced in the partition with the largest mutual inductance among the four partitions of the large coil, so that the number of coil turns in the target partition is one less turn than the number of coil turns in other partitions of the large coil, thereby reducing the mutual inductance value of the target partition. The above two methods are used to reduce the difference between the mutual inductance value of the target partition and the mutual inductance value of other partitions, thereby achieving the effect of reducing the mutual inductance difference between each partition, improving the problem of offset inconsistency of the transformer, and enabling the primary coil of the transformer to achieve a current sharing state when applying this structure, ensuring the stability of parameters such as output current, output voltage, and output power, thereby ensuring that the charging efficiency, temperature rise, ripple and other performance of the wireless charging system are not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0042] Figure 1 It is a structural diagram of a coil winding structure in the prior art;

[0043] Figure 2 This is a schematic structural diagram of a first embodiment of a coil winding structure of the present invention;

[0044] Figure 3 A circuit diagram of a transformer according to the present invention;

[0045] Figure 4 Another structural schematic diagram of the first embodiment of the coil winding structure of the present invention;

[0046] Figure 5 It is a structural schematic diagram of a second embodiment of the coil winding structure of the present invention;

[0047] Figure 6 This is another structural schematic diagram of the second embodiment of the coil winding structure of the present invention;

[0048] Figure 7 This is another structural schematic diagram of the second embodiment of the coil winding structure of the present invention;

[0049] Figure 8This is a schematic flow chart of a first embodiment of a coil winding method according to the present invention;

[0050] Figure 9 Schematic diagram of the flow of the coil winding method according to the second embodiment of the present invention.

[0051] Description of Figure Numbers:

[0052] Label name Label name 10 Large coil 11 The first lead 12 Winding Department 13 The second lead 20 Small coil 21 Outer winding wire 22 Bend wire part 221 First side 222 Second side 23 The third lead 24 First connection end 25 Second connection terminal

[0053] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0054] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0055] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. In the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a device or system including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such a device or system. In the absence of further restrictions, the elements defined by the sentence "include..." do not exclude the presence of other identical elements in the device or system including the element.

[0056] In the present invention, unless otherwise expressly specified or limited, the terms "connection", "fixed", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. In the present invention, if there are descriptions involving "first", "second", etc., the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features.

[0057] Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances. Furthermore, the technical solutions of the various embodiments may be combined with each other, but this must be based on the fact that they can be implemented by those skilled in the art. If the combination of technical solutions is mutually inconsistent or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0058] Wireless charging for electric vehicles uses electromagnetic induction coupling to transfer energy from the grid to the battery in a contactless manner. Typically, a wireless charging system consists of two subsystems: the infrastructure side and the vehicle side, with no electrical or mechanical connection between the two subsystems.

[0059] As the core component of the wireless charging system, the loosely coupled transformer has a primary coil that belongs to the infrastructure-side subsystem and is installed on the ground, and a secondary coil that belongs to the vehicle-side subsystem and is installed on the car chassis. The primary coil and secondary coil are used for energy transmission and energy reception respectively, realizing energy transmission and thus wireless charging.

[0060] An analysis of existing technologies reveals that the vertical distance and horizontal offset between the primary and secondary coils of a loosely coupled transformer vary within a certain range, due to factors such as the uncertainty of the position between the ground and the vehicle chassis depending on the parking state and the distance between the ground and the vehicle chassis varying with the vehicle's load. For example, horizontally, the secondary coil of the vehicle chassis may be located to the left, rear, front, or rear of the primary coil on the ground, resulting in a horizontal offset.

[0061] The coil winding structures commonly used for the primary coil and secondary coil of the loosely coupled transformer in the existing wireless charging system are as follows: Figure 1 As shown, the problem with this coil winding structure is that when the secondary coil is offset by the same distance from the primary coil in different orientations, there is a large difference in the mutual inductance value of the transformer. This transformer offset inconsistency is usually manifested in that the mutual inductance value when offset to a certain orientation is significantly lower than the mutual inductance value when offset to other orientations. This brings difficulties to the design and control of the wireless charging system, and it is impossible to achieve a current-sharing state, which can easily cause the voltage or current of the electronic devices in the system to be too large, reducing the output power and charging efficiency of the wireless charging system, that is, affecting the function and performance of the wireless charging system.

[0062] In view of the technical problem of offset inconsistency in transformers in the prior art, the present invention provides a coil winding structure, a coil winding method, and a transformer. Specific embodiments and implementation methods are as follows:

[0063] Example 1

[0064] Reference Figure 2 , Figure 2 This is a schematic diagram of the structure of the first embodiment of the coil winding structure of the present invention; this embodiment provides a coil winding structure. The coil winding structure is applied to a coil, and the coil is wound on a magnetic sheet. The coil winding structure includes:

[0065] A large coil 10 having n turns wound by a wire, wherein n is a natural number;

[0066] The large coil 10 includes four partitions, including a target partition. The number of turns of the target partition satisfies at least one of the following conditions:

[0067] When the target partition is the partition with the smallest mutual inductance value among the four partitions, the coil winding structure further includes a small coil 20 connected to the n-turn large coil 10, and the small coil 20 is located in the target partition. The total number of turns of the coil winding structure is turns, the number of turns of the target partition is n+1 turns; or,

[0068] When the target partition is the partition with the largest mutual inductance value among the four partitions, the total number of turns of the coil winding structure is The number of turns of the target partition is n-1 turns.

[0069] In the specific implementation process, the corresponding operation process is:

[0070] Wind n turns of a large coil on the magnetic sheet through a wire;

[0071] determining a target partition based on the four partitions of the large coil;

[0072] When the target partition is the partition with the smallest mutual inductance value among the four partitions, a small coil is wound in the target partition so that the number of turns of the target partition is n+1 turns, and the total number of turns of the coil winding structure is turn;

[0073] When the target partition is the partition with the largest mutual inductance value among the four partitions, within the target partition, subtract The number of turns of the coil is n-1, so that the number of turns of the target partition is n-1. The total number of turns of the coil winding structure is Turn.

[0074] Specifically, the four partitions are four quadrants in a coordinate system established with the center of the large coil as the origin. In this embodiment, the target partition is the partition with the smallest mutual inductance value among the four partitions. Figure 1 The large coil 10 shown, assuming Figure 1The second quadrant area of the medium and large coil 10, that is, the partition (2) in the figure, is the partition with the smallest mutual inductance value among the four partitions, that is, the target partition. In this embodiment, a small coil 20 is connected to the large coil in the target partition, such as Figure 2 As shown in the figure, area (2) has one more turn than other areas. When the number of turns of the large coil is n, the number of turns of the target partition is n+1, and the total number of turns of the coil winding structure is When n is an integer, it means that the starting point and the end point of the large coil correspond to each other and each coil is complete. Figure 1 As shown in , when n is a non-integer natural number, it means that the starting point and end point of the large coil do not correspond to each other, and the wound coil may have half a turn or a quarter turn, because in actual implementation, not all coils must have their starting points and end points in the same partition.

[0075] Specifically, the coil winding structure can be applied to the primary coil and secondary coil of the loosely coupled transformer, or only the primary coil or the secondary coil can adopt the coil winding structure. In this embodiment, the loosely coupled transformer can be applied to the wireless charging system of electric vehicles, which includes an infrastructure side subsystem and an on-board side subsystem. The primary coil of the loosely coupled transformer belongs to the infrastructure side subsystem, and the secondary coil belongs to the on-board side subsystem. Figure 3 The figure shows the circuit schematic diagram of the wireless charging system. The left side of the figure is the infrastructure side subsystem, and the right side is the vehicle side subsystem, which respectively transmit and receive energy. Lp represents the primary coil of the loosely coupled transformer, Ls represents the secondary coil of the loosely coupled transformer, Ip represents the current of the primary coil, Is represents the current of the secondary coil, and M represents the mutual inductance of the loosely coupled transformer. The mutual inductance M varies with the physical distance and offset between the primary coil Lp and the secondary coil Ls. This embodiment is based on Figure 3 The circuit diagram shown in Figure 2 The coil winding structure shown is specifically applied to the primary coil Lp.

[0076] During the specific implementation process, the position and size of the small coil can be set according to the size, structure and 10 turns of the transformer in which it is located. In this embodiment, the primary coil of the structure is used as an example, and the optimal position and size of the small coil are obtained through specific experimental comparison or simulation comparison, so that the difference between the mutual inductance values M of the transformers with the secondary coil offset by the same distance to the four partitions is minimized.

[0077] Furthermore, the large coil 10 includes:

[0078] A first lead-out terminal 11 located on the inner side;

[0079] A winding portion 12 wound from inside to outside, wherein the winding portion 12 includes n turns of winding;

[0080] A second lead-out terminal 13 located on the outside;

[0081] The first lead-out end 11 is disposed at the starting point of the first winding, and the second lead-out end 13 is disposed at the ending point of the nth winding.

[0082] Specifically, the first lead-out terminal 11 and the second lead-out terminal 13 can be led out in the same direction, and the specific lead-out positions of the first lead-out terminal 11 and the second lead-out terminal 13 can be in the same partition or in different partitions, for example Figure 1 In the figure, the first lead-out terminal 11 is in the (2) partition in the figure, and the second lead-out terminal 13 is in the (1) partition in the figure. Of course, the first lead-out terminal 11 can also be in the (1) partition in the figure, and the second lead-out terminal 13 can be in the (2) partition in the figure. The specific setting can be made according to actual conditions.

[0083] In this embodiment, the winding portion wound from the inside to the outside includes 6 turns of winding. The first lead-out terminal 11 and the second lead-out terminal 13 can be in the same partition. When they are in the same partition, the transformer mutual inductance M is the smallest when the secondary coil is offset to the partition, that is, the partition is the target partition. Figure 2 As shown, the first lead-out terminal 11 and the second lead-out terminal 13 are both in the second quadrant area of the coordinate system established with the center of the large coil 10 as the origin, that is, the (2) partition in the figure.

[0084] Furthermore, the small coil includes:

[0085] The outer winding wire portion 21 and the bent wire portion 22 are connected in sequence;

[0086] The position and length of the bent wire portion 22 are adjustable within the target partition to adjust the winding area of the small coil.

[0087] In this embodiment, based on Figure 2 The large coil 10 structure shown in FIG. 1 is a structure in which the position and length of the small coil are adjustable. Correspondingly, the winding area of the coil is adjustable. Figure 4 In the coil winding structure diagram shown in FIG. 1 , the first side 221 of the bent wire portion 22 is on the x-axis of the coordinate system, and the second side 222 is on the y-axis of the coordinate system. Under the premise that the lead-out portion of the small coil and the first lead-out end 11 of the large coil 10 are required to be led out in the same direction, only the position of the first side 221 can be moved, for example, Figure 4As in the figure, the first side 221 is moved forward or backward by 2 mm in the y-axis direction, and the length of the second side 222 is adjusted accordingly. In this way, a plurality of small coils with different winding areas can be obtained, so that the coil current of the coil in the partition changes. In the specific implementation process, the final result can be determined based on a specific experiment or simulation test. Among them, the final result is based on the minimum mutual inductance value among the four mutual inductance values of each test when the four partitions are offset. The minimum mutual inductance value is selected as the maximum, and when the difference between the maximum mutual inductance value and the minimum mutual inductance value is the smallest, the position of the first side 221 and the second side 222 of the corresponding bent wire portion 22 is the final result. In accordance with the size, structure and number of turns of the transformer, the position of the first side 221 of the small coil and the length of the second side 222 are different, which can be set according to the actual situation and are not limited here.

[0088] Furthermore, when the target partition is the first partition, the small coil further includes a third lead-out end 23;

[0089] The outer winding wire portion 21 is connected to the second lead-out end 13 and is located outside the n-th winding turn of the first partition. The bent wire portion 22 is connected to the third lead-out end 23, and the third lead-out end 23 is led out in the same direction as the first lead-out end 11.

[0090] The first partition is a quadrant where the second lead-out end 13 is located in a coordinate system established with the center of the large coil 10 as the origin.

[0091] like Figure 2 In the schematic diagram of the structure shown, the target partition is the first partition, that is, the second quadrant area where the second lead-out terminal 13 is located in the coordinate system established with the center of the large coil 10 as the origin, that is, area (2) in the figure. At this time, the first lead-out terminal 11 of the large coil 10 can be in this area or not. Correspondingly, the outer winding wire portion 21 of the small coil can be directly connected to the second lead-out terminal 13 and wound around the outside of the nth winding turn of the large coil 10. For example, the total number of turns of the coil in this embodiment is n, and the outer winding wire portion 21 of the small coil is located outside the sixth winding turn of the wire in the second quadrant. The bent wire portion 22 is connected to the outer winding wire portion 21, and the first side 221 of the bent wire portion 22 is arranged horizontally. Based on the requirement of this embodiment that the lead-out portion of the small coil and the first lead-out terminal 11 of the large coil 10 are led out in the same direction, the second side 222 of the bent wire portion 22 is wound around the first lead-out terminal 11 in the y-axis direction based on the position of the first lead-out terminal 11 based on the x-axis. The second side 222 is connected to the third lead-out terminal 23, and the third lead-out terminal 23 can be led out in the same direction as the first lead-out terminal 11. It should be noted that in this embodiment, the third lead-out terminal 23 is not limited to being located on the left or right side of the first lead-out terminal 11, but this does not rule out the possibility of such a requirement in actual use.

[0092] Furthermore, the position of the wire of the bent wire portion 22 is adjustable in the x-direction and / or the y-direction of a coordinate system established with the center of the large coil 10 as the origin.

[0093] Figure 2 The embodiment shown is arranged based on the premise that the third lead-out end 23 and the first lead-out end 11 are required to be led out in the same direction. In the specific implementation process, when the position of the third lead-out end 23 is not required, in order to adjust the position and size of the small coil, the position of the first side 221 of the bent wire portion 22 can be moved in the y-axis direction, and the position and length of the second side 222 can be adjusted accordingly. The position of the second side 222 of the bent wire portion 22 can also be moved in the x-axis direction, and the position and length of the first side 221 can be adjusted accordingly. The position of the second side 222 of the bent wire portion 22 can also be moved in the x-axis direction and the position of the first side 221 can be moved in the y-axis direction, while adjusting the positions and lengths of the first side 221 and the second side 222. In short, the purpose is to adjust the winding area of the small coil, thereby adjusting the mutual inductance value of the first partition, that is, the mutual inductance value of the transformer when the secondary coil is offset to the first partition compared to the primary coil.

[0094] Furthermore, the wire is a multi-strand wire.

[0095] Because the mutual inductance of a loosely coupled transformer is low, the required primary coil current Ip and secondary coil current Is are large to achieve power transmission. This can easily lead to significant losses in the primary and secondary coils. To address this, the coils are wound using multiple strands of wire to reduce internal resistance and losses.

[0096] Furthermore, the large coil 10 is any one of an elliptical coil, a circular coil, a square coil, a polygonal coil and a DD coil.

[0097] In order to verify the effect of the coil winding structure of this embodiment, Figure 1 The coil winding structure of the prior art shown Figure 2 The coil winding structure of the embodiment shown in the figure was tested. Specifically,

[0098] In such Figure 1 In the prior art shown, the coil winding structure only has a large coil. Assuming that the primary coil and the secondary coil of the loosely coupled transformer in the wireless system are both Figure 1The coil winding structure includes a large coil, which includes a first lead-out terminal 11, a wire portion 12, and a second lead-out terminal 13. The first lead-out terminal 11 and the second lead-out terminal 13 are led out in the same direction. In the primary coil, a coordinate system is established with the center of the large coil as the origin. Based on the coordinate system, the primary coil is subjected to an offset test with the secondary coil, specifically offsetting the same distance to the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant to obtain the transformer mutual inductance value M offset to different areas; at the same time, Figure 2 The coil winding structure shown is used as the primary coil Lp of a loosely coupled transformer. The center point of the secondary coil Ls, which uses the same structure, is offset relative to four partitions of the primary coil Lp. Specifically, the center point is offset by the same distance to the first, second, third, and fourth quadrants to obtain the transformer mutual inductance M offset to different regions. The results are shown in Table 1.

[0099] Table 1

[0100] Mutual inductance value M Zone 1 (uH) Zone 2 (uH) Zone 3 (uH) Zone 4 (uH) Figure 1 5.920 5.433 6.035 6.043 Figure 2 6.018 5.953 6.228 5.960

[0101] As can be seen from the table above, there are indeed inconsistencies in the mutual inductance values of the transformers in different offset directions. However, for the coil winding structure of the prior art, the difference between the mutual inductance value M offset to the fourth quadrant (the maximum value among the four partitions) and the mutual inductance value M offset to the second quadrant (the minimum value among the four partitions) is 6.043-5.433=0.61. However, for the coil winding structure of this embodiment, the difference between the mutual inductance value M offset to the third quadrant (the maximum value among the four partitions) and the mutual inductance value M offset to the second quadrant (the minimum value among the four partitions) is 6.228-5.953=0.275. Thus, compared with the prior art, this embodiment significantly reduces the difference in mutual inductance values between the offsets to different partitions, improves the offset inconsistency problem, stabilizes parameters related to the wireless charging system's functions, such as output power, output current, and output voltage, and reduces the impact on parameters related to the wireless charging system's performance, such as charging efficiency, temperature rise, and ripple, thereby meeting system function and performance requirements and improving system efficiency.

[0102] The coil winding structure of this embodiment adopts a small coil connected to a large coil of n turns wound with a wire, and the small coil is located in the partition with the smallest mutual inductance among the four partitions of the large coil, so that the number of coil turns in the target partition is one more turn than the number of coil turns in other partitions of the large coil, thereby improving the mutual inductance value of the target partition; the large coil can also be reduced in the partition with the largest mutual inductance among the four partitions of the large coil, so that the number of coil turns in the target partition is one less turn than the number of coil turns in other partitions of the large coil, thereby reducing the mutual inductance value of the target partition; the above two methods are used to reduce the difference between the mutual inductance value of the target partition and the mutual inductance value of the other partitions, thereby achieving the effect of reducing the mutual inductance difference between each partition, improving the problem of offset inconsistency of the transformer, so that when the primary coil of the transformer is applied with this structure, it can achieve a current sharing state, ensuring the stability of parameters such as output current, output voltage and output power, thereby ensuring that the charging efficiency, temperature rise, ripple and other performance of the wireless charging system are not affected.

[0103] Example 2

[0104] Reference Figures 5 to 7 Based on the first embodiment, this embodiment further proposes a coil winding structure.

[0105] Furthermore, when the target partition is the second partition, the small coil further includes a first connection end 24 and a second connection end 25;

[0106] The first connection end 24 is connected to the outer winding wire portion 21 and is disposed on the m-th winding wire of the second partition. The outer winding wire portion 21 is located between the m-1-th winding wire and the m-th winding wire of the large coil, where m≤n and m is a natural number.

[0107] One end of the second connection end 25 is connected to the bent wire portion 22, is disposed on the (m+1)th winding of the second partition and is located outside the first connection end 24, and the other end is connected to the (m)th winding of the large coil;

[0108] The second lead-out end 13 and the first lead-out end 11 are led out in the same direction;

[0109] The second partition is any quadrant area outside the first partition in a coordinate system established with the center of the large coil as the origin.

[0110] Specifically, in actual use, there may be a situation where the partition where the first lead-out terminal 11 of the large coil is located is not the target partition. Assuming that the second lead-out terminal is still in the second quadrant area, any other quadrant area may be the second partition. That is, based on the first embodiment, the second quadrant area is not the partition with the smallest mutual inductance value. For example, Figure 5 、 Figure 6 and Figure 7 The coil winding structure diagrams shown are schematic diagrams of the coil winding structure when the target areas are the third quadrant area, the fourth quadrant area, and the first quadrant area, respectively. That is, the third quadrant area, the fourth quadrant area, and the first quadrant area are respectively used as the target areas.

[0111] Specifically, m is a natural number less than or equal to n, indicating that the small coil can be connected to any turn of the large coil. In this embodiment, n is 6, so m can be any value less than or equal to 6. It should be noted that m and n are natural numbers, which means they can be non-integers. When they are not integers, it means that the starting point and end point of the coil do not completely correspond, and the coil is not wound into a complete circle, that is, it can be a half circle or 1 / 4 circle, etc. When m is equal to 6, a small coil is connected to the outermost wire of the large coil. Figures 5 to 7 Take m=6 as an example.

[0112] In this embodiment, if Figure 5 As shown, the first connection end 24 is connected to the sixth turn of the large coil in the partition, and the external conductor portion of the small coil is connected to the first connection end 24. The external conductor portion is wound to replace the original sixth turn of the large coil, that is, the external conductor portion is located between the sixth and fifth turns of the large coil. From the perspective of the partition at this time, the external conductor portion is the sixth turn of the partition, and the original sixth turn of the large coil in the partition becomes the seventh turn of the partition. Without leaving the partition, when the external conductor portion is wound to a certain position, it connects to the first side 221 of the bent conductor portion 22. At this time, the first side 221 is parallel to the y-axis of the coordinate system, and the second side 222 of the bent conductor portion 22 is parallel to the x-axis of the bent conductor portion 22. Accordingly, the position and length of the first side 221 and the second side 222 are adjustable. After the second side 222 is wound to the junction of the small coil and the large coil, that is, the second connection end 25, the bent wire portion 22 of the small coil is connected to the sixth wire loop of the large coil in this area through the second connection end 25. The sixth wire loop is led out through the second lead-out end 13 of the large coil based on the original winding method. Figure 5 In the coil shown, the coil in the third quadrant has one more turn than in the other quadrants. This increases the coil current in this quadrant, thereby increasing the mutual inductance. Increasing the mutual inductance of the quadrant with the smallest mutual inductance can reduce the difference in mutual inductance between the quadrants. Figure 6 and Figure 7 The coil winding structure shown is also wound in a similar manner and will not be described in detail here.

[0113] The coil winding structure of this embodiment expands upon the first embodiment to illustrate the coil winding structure when the target region is not the region where the first or second lead of the large coil resides, that is, when the target region is the first, third, or fourth quadrant of the coordinate system. This coil winding structure can be applied to transformers in a wider range of situations, meeting the requirements of transformers in wireless charging systems.

[0114] Example 3

[0115] Reference Figure 8 , Figure 8 1 is a flow chart of a first embodiment of a coil winding method according to the present invention. This embodiment provides a coil winding method, comprising:

[0116] Step S1: Wind n turns of a large coil on a magnetic sheet using a conductive wire, where n is a natural number.

[0117] Specifically, the wire used is a multi-strand wire, and the large coil can be any one of an elliptical coil, a circular coil, a square coil, a polygonal coil and a DD coil. Figure 2 As shown, the large coil is wound into 6 turns.

[0118] Step S2: determining a target partition based on the four partitions of the large coil, wherein the target partition is the partition with the smallest mutual inductance value or the partition with the largest mutual inductance value among the four partitions.

[0119] Specifically, such as Figure 2 As shown, a coordinate system is established with the center of the large coil as the origin, and four partitions are obtained based on the four quadrants of the coordinate system. In the specific implementation process, when winding the primary coil, the center of the secondary coil can be used to offset the four partitions of the primary coil by the same distance to obtain the transformer mutual inductance value M, and the partition with the smallest mutual inductance value or the partition with the largest mutual inductance value is used as the target partition; when winding the secondary coil, the center of the primary coil can be used to offset the four partitions of the secondary coil by the same distance to obtain the transformer mutual inductance value M, and the partition with the smallest mutual inductance value or the partition with the largest mutual inductance value is used as the target partition. It should be noted that the primary coil and the secondary coil should be consistent, that is, either the partition with the largest mutual inductance value is selected as the target partition, or the partition with the smallest mutual inductance value is selected as the target partition.

[0120] In practical applications, the starting and ending points of the large coil are generally located in the partitions with the smallest mutual inductance value, that is, Figure 2 (2) partition. Of course, it is not ruled out that there are other partitions with the smallest mutual inductance value, that is, Figure 5 (3) Partitions in Figure 6 (4) partition or Figure 7 (1) Partition in.

[0121] Step S3: When the target partition is the partition with the smallest mutual inductance value among the four partitions, a small coil is wound in the target partition so that the number of turns of the target partition is n+1 turns, and the total number of turns of the coil winding structure is turns, wherein the small coil is connected to the n-turn large coil.

[0122] Specifically, such as Figure 2 The structural schematic diagram shown, that is, when the target partition is the first partition, wherein the first partition is the second quadrant area in the coordinate system established with the center of the large coil as the origin, the small coil is directly connected to the end point of the large coil, that is, the second lead-out end, and the outer winding wire portion of the small coil is coiled around the outside of the nth turn of the wire of the large coil. Then, the first side of the bent wire portion of the small coil is parallel to the x-axis of the coordinate system, and the second side is parallel to the y-axis, so that the third lead-out end connected to the bent wire portion is led out in the same direction as the first lead-out end of the large coil.

[0123] like Figure 5 The structural diagram shown, i.e., when the target partition is the second partition, wherein the second partition is the first quadrant, the third quadrant, or the fourth quadrant in a coordinate system established with the center of the large coil as the origin, is shown. This embodiment uses the third quadrant as an example to illustrate the target partition. The first connection end of the small coil is connected to the nth wire turn of the large coil in the target partition. The outer winding portion is wound around the outside of the n-1th wire turn of the large coil and located inside the original nth wire turn. In other words, the outer winding portion replaces the original nth wire turn of the large coil in the target partition, turning the original nth wire turn into the n+1th wire turn. The bent wire portion of the small coil is then wound back to the first connection end, with a first side parallel to the y-axis of the coordinate system and a second side parallel to the x-axis. To prevent the wires from becoming tangled, the second connection end at the connection with the original nth wire turn is positioned outside the first connection end. The second connection end is then connected to the nth wire turn of the large coil. The end point of the nth wire turn, i.e., the second lead-out end, extends in the same direction as the first lead-out end of the large coil.

[0124] It should be noted that the functions that can be achieved in each step of the coil winding method provided in this embodiment and the corresponding technical effects can be referred to the description of the specific implementation methods in each embodiment of the coil winding structure of the present invention. For the sake of brevity of the description, they will not be repeated here.

[0125] Example 4

[0126] Reference Figure 9 , Figure 9 This is a flow chart of the second embodiment of the coil winding method of the present invention. Based on the third embodiment, this embodiment further proposes a coil winding method.

[0127] Furthermore, after step S2, the method may further include:

[0128] Step S4: When the target partition is the partition with the largest mutual inductance value among the four partitions, subtract The number of turns of the coil is n-1, so that the number of turns of the target partition is n-1. The total number of turns of the coil winding structure is Turn.

[0129] After determining the target partition, that is, the partition with the largest mutual inductance value, subtract one turn from the large coil in the partition. For example, assuming Figure 1 The (1) partition is the partition with the largest mutual inductance value. Based on this structure, the second lead-out terminal 13 can be directly moved forward to the 6th turn of the (1) partition close to the x-axis, and then the lead-out terminal can be moved to the left along the x-axis close to the origin, and then led out in the same direction as the first lead-out terminal 11. At this time, the number of turns of this partition is only 5 turns, and correspondingly, its mutual inductance value will be reduced, so that the overall mutual inductance value difference of the coil winding structure will also be reduced. When other partitions are used as target partitions, the target partitions can also be reduced in turns according to actual conditions. At this time, the first lead-out terminal and the second lead-out terminal can no longer be restricted from being led out in the same direction. It can be set according to actual conditions and will not be repeated here.

[0130] It should be noted that for more implementation details of the coil winding method provided in this embodiment, please refer to the description of the implementation method of the corresponding steps in Example 3. The functions that can be achieved in each step and the corresponding technical effects can be referred to the description of the specific implementation methods in each embodiment of the coil winding structure of the present invention. For the sake of brevity of the specification, they will not be repeated here.

[0131] Example 5

[0132] Reference Figure 3 , Figure 3 : is a circuit diagram of a transformer of the present invention; this embodiment provides a transformer, which includes:

[0133] A magnetic sheet, and a coil wound on the magnetic sheet;

[0134] The coil adopts the coil winding structure as described in the first or second embodiment above.

[0135] Furthermore, the coil includes:

[0136] Primary coil and secondary coil;

[0137] The primary coil adopts the coil winding structure, and / or

[0138] The secondary coil adopts the coil winding structure.

[0139] Specifically, in the primary coil and secondary coil of the transformer, the coil winding structure of the present invention may be adopted by both the primary coil and the secondary coil, or only the primary coil or only the secondary coil may adopt the coil winding structure of the present invention.

[0140] Among them, the specific structure of the coil winding structure refers to the above embodiments. Since this embodiment adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0141] It should be noted that the serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0142] The above descriptions are merely optional embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made based on the contents of the present invention's description and drawings, or directly or indirectly applied to other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A coil winding structure, characterized in that: Applied to a coil, the coil is wound on a magnetic sheet, and the coil winding structure includes: A large coil of n turns wound with a conductor, the large coil of n turns being applied to the primary coil and / or secondary coil of a transformer, wherein n is a natural number, the large coil of n turns including four partitions, the four partitions including a target partition, the target partition being determined by measuring the mutual inductance values of the four partitions, the mutual inductance values of the four partitions being the mutual inductance values of the transformer when the secondary coil is offset by the same distance from the four partitions of the primary coil, or the mutual inductance values of the transformer when the primary coil is offset by the same distance from the four partitions of the secondary coil, and the number of turns of the target partition meeting at least one of the following conditions: In the case where the target partition is the partition with the smallest mutual inductance value among the four partitions, the coil winding structure further includes a small coil connected to the n-turn large coil, and the small coil is located in the target partition. The number of turns of the target partition is n+1 turns, and the total number of turns of the corresponding coil winding structure is turns; or, In the case where the target partition is the partition with the largest mutual inductance value among the four partitions, within the target partition, subtract The number of turns of the large coil is n-1, so that the number of turns of the target partition is n-1, and the total number of turns of the corresponding coil winding structure is Turn.

2. The coil winding structure according to claim 1, characterized in that: The large coil comprises: A first lead-out terminal located on the inner side; A winding portion wound from inside to outside, the winding portion including n turns of winding; A second lead-out terminal located on the outside; The first lead-out end is arranged at the starting point of the first winding circle, and the second lead-out end is arranged at the ending point of the nth winding circle.

3. The coil winding structure according to claim 2, characterized in that: The small coil comprises: An outer winding conductor portion and a bent conductor portion connected in sequence; The position and length of the bent wire portion are adjustable within the target partition to adjust the winding area of the small coil.

4. The coil winding structure according to claim 3, characterized in that: When the target partition is the first partition, the small coil further includes a third lead-out end; The outer winding wire portion is connected to the second lead-out end and is located outside the n-th winding turn of the first partition; the bent wire portion is connected to the third lead-out end, and the third lead-out end and the first lead-out end are led out in the same direction; The first partition is a quadrant area where the second lead-out end is located in a coordinate system established with the center of the large coil as the origin.

5. The coil winding structure according to claim 4, characterized in that: When the target partition is the second partition, the small coil further includes a first connection end and a second connection end; The first connection end is connected to the outer winding wire portion and is disposed on the mth winding wire of the second partition, and the outer winding wire portion is located between the m-1th winding wire and the mth winding wire of the large coil, where m≤n, and m is a natural number; One end of the second connection end is connected to the bent wire portion, is disposed on the (m+1)th winding of the second partition and is located outside the first connection end, and the other end is connected to the (m)th winding of the large coil; The second lead-out end and the first lead-out end are led out in the same direction; The second partition is any quadrant area outside the first partition in a coordinate system established with the center of the large coil as the origin.

6. The coil winding structure according to claim 5, characterized in that: The position of the conductor of the bent conductor portion is adjustable in the x-direction and / or the y-direction of a coordinate system established with the center of the large coil as the origin.

7. The coil winding structure according to claim 1, wherein: The wire is a multi-strand wire.

8. A coil winding method for the coil winding structure according to any one of claims 1 to 7, characterized in that: The method comprises: A large coil with n turns of wire is wound on the magnetic sheet, where n is a natural number; Based on the four partitions of the large coil, determining a target partition, wherein the target partition is a partition with the smallest mutual inductance value or a partition with the largest mutual inductance value among the four partitions; When the target partition is the partition with the smallest mutual inductance value among the four partitions, a small coil is wound in the target partition so that the number of turns of the target partition is n+1 turns, and the total number of turns of the coil winding structure is turns, wherein the small coil is connected to the n-turn large coil; or, In the case where the target partition is the partition with the largest mutual inductance value among the four partitions, within the target partition, subtract The number of turns of the coil is n-1, so that the number of turns of the target partition is n-1. The total number of turns of the coil winding structure is Turn.

9. A transformer, characterized in that: The transformer comprises: A magnetic sheet, and a coil wound on the magnetic sheet; The coil adopts the coil winding structure according to any one of claims 1 to 7, and the large coil in the coil winding structure is any one of an elliptical coil, a circular coil, a square coil, a polygonal coil and a DD coil.

10. The transformer according to claim 9, characterized in that The coil comprises: Primary coil and secondary coil; The primary coil adopts the coil winding structure, and / or The secondary coil adopts the coil winding structure.

Images