A flat wire winding structure

Abstract

The invention discloses a flat wire winding structure, belonging to the field of motor technology, comprising a stator core, wherein the upper and lower sides of the stator core are respectively the connection side and the insertion side of the flat wire, and the inner side surface of the stator core is provided with a plurality of evenly distributed axial slots along the circumferential direction, the number of winding poles of the flat wire winding structure is 2p, the number of slots of the axial slots is m, each axial slot is provided with 2n layers of conductors, and a flat wire U-shaped hairpin is inserted in the axial slot, and the flat wire U-shaped hairpin includes three pitch structures of full pitch Y1=m / 2p, long pitch Y2≥Y1+1 and short pitch Y3≤Y1‑1, and Y2‑Y3=m / 2p / 3, and the flat wire U-shaped hairpin adopts a cross-layer structure of two adjacent layers. The invention adopts a single-branch triangle wiring mode or a single-branch star wiring mode or a double-branch star wiring mode, and the potentials of the three modes are balanced, there is no circulating current problem, and the winding structure is simple and has no special-shaped wires.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and more particularly to a flat wire winding structure. Background Art

[0002] Miniaturization and high speed will be the main development trends of new energy vehicle motors, and miniaturization will inevitably require a significant increase in motor power density. To achieve this increase in motor power density, the use of "flat wire motor" technology has become the best choice for the motor industry in recent years.

[0003] After searching, it was found that the publication number "CN115955022A" records "a flat wire motor stator structure. The flat wire motor stator structure includes a stator core, and a plurality of axial slots are evenly spaced along the circumferential direction on the inner side surface of the stator core. The two ends of the stator core are respectively an insertion side and a welding side. A flat wire hairpin is inserted in each axial slot. The flat wire hairpin is electrically connected by welding on the welding side to form a three-phase winding of the flat wire motor: a U-phase winding, a V-phase winding and a W-phase winding. The lead-out wire end and the neutral wire end of each phase winding are both arranged on the insertion side. By arranging the lead-out wire end and the neutral wire end of each phase winding on the insertion side, that is, welding the corresponding lead-out wire bus and the neutral wire bus on the insertion side, a flat wire winding scheme with low winding ends is realized, which can save the cost increase caused by bridge wires, reduce the difficulty of winding coating process, and improve the insulation performance of the motor";

[0004] The above patent can effectively reduce the difficulty of winding welding and insulation treatment, and reduce the axial space size of the motor stator;

[0005] However, the above patent adopts a technical solution including I-type flat wires and U-type hairpin flat wires, wherein: the I-type flat wires have 6c, and the U-type hairpin flat wires include three types with pitches of Y1=n / p-1, Y2=n / p and Y3=n / p+1;

[0006] The above technical solution requires many I-type and U-shaped flat wires. After adopting the above technical solution, it may cause potential imbalance in the motor, and then produce circulating current phenomenon. At the same time, the above solution requires two types of flat wires, I-type and U-shaped. Each type of flat wire has a variety of shapes, which makes its winding structure relatively complicated. At the same time, each type of flat wire needs to develop a corresponding mold, and the manufacturing cost is too high, which is not suitable for mass production. Summary of the invention

[0007] Technical issues to be solved

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide a flat wire winding structure, which adopts a single-branch triangle connection method or a single-branch star connection method or a double-branch star connection method. There is no circulating current problem in the potential balance. There are only U-type flat wires, no special-shaped wires and no I-type flat wires. This winding structure is simple and there are few types of U-shaped hairpin flat wires, so there are few molds and low costs, and the process manufacturing is good, which is suitable for mass production.

[0009] To solve the above problems, the present invention adopts the following technical solutions:

[0010] A flat wire winding structure comprises a stator core, wherein the upper and lower sides of the stator core are respectively a connection side and an insertion side of the flat wire, and a plurality of evenly distributed axial slots are provided on the inner side surface of the stator core along the circumferential direction, wherein:

[0011] The number of winding poles of the flat wire winding structure is 2p, the number of slots of the axial slot is m, each of the axial slots is provided with insulating paper and 2n layers of conductors, and along the direction of the stator core axis from the outside to the inside are the 2nth layer, the 2n-1th layer, the 2n-2th layer, ..., the 1st layer, wherein: p≥4, n≥2, and p, m and n are all natural numbers;

[0012] A flat wire U-shaped hairpin is inserted into the axial slot, and the flat wire U-shaped hairpin includes three pitch structures: full pitch Y1=m / 2p, long pitch Y2≥Y1+1, and short pitch Y3≤Y1-1, and Y2-Y3=m / 2p / 3, wherein: Y1, Y2, and Y3 are all integers, and the pitch unit is "cross-slot";

[0013] The flat wire U-shaped hairpin adopts a cross-layer structure of two adjacent layers;

[0014] The flat wire U-shaped hairpin is inserted through the insertion side and then electrically connected on the connection side by twisting and bending, and finally forms a three-phase winding of the flat wire winding structure: a U-phase winding, a V-phase winding and a W-phase winding, and the lead wire ends of the U-phase winding, the V-phase winding and the W-phase winding are arranged on the connection side;

[0015] The flat wire winding structure adopts a single-branch delta connection mode, a single-branch star connection mode, or a double-branch star connection mode.

[0016] As a preferred solution of the present invention, when the flat wire winding structure adopts a single-branch triangle connection method:

[0017] W- is connected to U+ as the lead-out terminal of the U-phase winding;

[0018] U- is connected to V+ as the lead-out terminal of the V-phase winding;

[0019] V- is connected to W+ as the lead-out terminal of the W-phase winding;

[0020] When the flat wire winding structure adopts a single-branch star connection mode, it is not necessary to adjust the wiring mode and add a flat wire U-shaped hairpin, wherein:

[0021] U+ is used as the lead-out terminal of the U-phase winding;

[0022] V+ is used as the lead-out terminal of the V-phase winding;

[0023] W+ is used as the lead-out terminal of the W-phase winding;

[0024] U-, V- and W- are connected together as the star connection neutral point;

[0025] When the flat wire winding structure adopts a double-branch star connection mode, it does not add a flat wire U-shaped hairpin, but needs to adjust the wiring form, that is, cancel the reverse U-shaped hairpin or use two reverse U-shaped hairpins for each phase, and at the same time, it needs to add a neutral copper bar, where:

[0026] U1+ and U2+ are connected together to serve as the U-phase winding lead-out terminal;

[0027] V1+ and V2+ are connected together to serve as the V-phase winding lead-out terminal;

[0028] W1+ and W2+ are connected together to serve as the W-phase winding lead-out terminal;

[0029] U1-, U2-, V1-, V2-, W1- and W2- are connected to the neutral copper bus and serve together as the neutral line of the double-branch star connection.

[0030] As a preferred solution of the present invention, the cross-layer structure of two adjacent layers includes:

[0031] A reverse cross-layer structure of 2n to 2n-1 layers, 2n-2 to 2n-3 layers, ..., 2 to 1 layer; and

[0032] A forward cross-layer structure of 1 to 2 layers, ..., 2n-3 to 2n-2 layers, and 2n-1 to 2n layers.

[0033] As a preferred solution of the present invention, the flat wire U-shaped hairpin includes a flat wire U-shaped hairpin body, the bottom of the flat wire U-shaped hairpin body is a twisted segment to form a cross-layer structure, and the flat wire U-shaped hairpin body is inserted into the axial slot and bent to obtain two bent segments, and the two bent segments have a first state and a second state, wherein:

[0034] The first state is: the two bending sections have opposite bending directions;

[0035] The second state is that the two bending sections have the same bending direction.

[0036] As a preferred solution of the present invention, the flat wire winding structure includes any one of 8-pole 48 slots, 10-pole 60 slots, 12-pole 72 slots and 16-pole 96 slots, and each of the axial slots is provided with any one of 4 layers, 6 layers, 8 layers, 10 layers and 12 layers of conductors.

[0037] As a preferred solution of the present invention, the flat wire winding structure has 8 poles and 48 slots, the number of winding poles of the flat wire winding structure is 8, the number of slots of the axial slots is 48, and each of the axial slots is provided with 6 layers of conductors. After calculation, it is obtained that: p=4, m=48, n=3.

[0038] As a preferred solution of the present invention, p=4, m=48, n=3 are substituted into Y1=m / 2p, Y2≥Y1+1, Y3≤Y1-1, Y2-Y3=m / 2p / 3, and after calculation, the full pitch Y1 of the flat wire U-shaped hairpin is obtained as 6 cross slots, the long pitch Y2 is 7 cross slots, and the short pitch Y3 is 5 cross slots.

[0039] As a preferred solution of the present invention, the flat wire U-shaped hairpin adopts:

[0040] 6 to 5 layers, 4 to 3 layers, 2 to 1 layer reverse cross-layer structure; and

[0041] The forward cross-layer structure is 1 to 2 layers, 3 to 4 layers, and 5 to 6 layers.

[0042] As a preferred solution of the present invention, in one branch of the U-phase winding:

[0043] When the flat wire U-shaped hairpin adopts a 6-to-5-layer reverse cross-layer structure, the pitches are 6, 7, 5, 7, 6, 5, 7, 5 in sequence;

[0044] When the flat wire U-shaped hairpin adopts a 4-to-3-layer reverse cross-layer structure, the pitches are 6, 7, 5, 7, 6, 5, 7, 5 in sequence;

[0045] When the flat wire U-shaped hairpin adopts a 2-to-1 reverse cross-layer structure, the pitches are 6, 7, 5, 7, 6, 5, 7, 5 in sequence;

[0046] When the flat wire U-shaped hairpin adopts a 1-to-2-layer forward cross-layer structure, the pitches are 5, 7, 5, 6, 7, 5, 7, 6 in sequence;

[0047] When the flat wire U-shaped hairpin adopts a 3-to-4-layer forward cross-layer structure, the pitches are 5, 7, 5, 6, 7, 5, 7, 6 in sequence;

[0048] When the flat wire U-shaped hairpin adopts a 5-turn 6-layer forward cross-layer structure, the pitches thereof are 5, 7, 5, 6, 7, 5, 7, 6 in sequence.

[0049] As a preferred solution of the present invention, "&" represents the connection part between the two flat wire U-shaped hairpins, and "ij" represents the jth layer in the i-th axial slot, then:

[0050] The electrical connection mode of the single branch of the U-phase winding is:

[0051] U+ & 40.6 & 34.5 & 28.6 & 21.5 & 15.6 & 10.5 & 4.6 & 45.5 & 39.6 &33.5 & 27.6 & 22.5 & 16.6 & 9.5 & 3.6 & 46.5 & 40.4 & 34.3 & 28.4 & 21.3 &15.4 & 10.3 & 4.4 & 45.3 & 39.4 & 33.3 & 27.4 & 22.3 & 16.4 & 9.3 & 3.4 &46.3 & 40.2 & 34.1 & 28.2 & 21.1 & 15.2 & 10.1 & 4.2 & 45.1 & 39.2 & 33.1 3.4 & 39.3 & 45.4 & 3.3 & 10.4 & 16.3 & 21.4 &27.3 & 34.4 & 40.3 & 46.4 & 4.5 & 9.6 & 15.5 & 22.6 & 28.5 & 3.1 & 10.2 & 16.1 & 21.2 & 27.1 & 34.2 & 40.1 & 46.2 & 4.3 &9.4 & 15.3 & 22.4 & 28.3 & 33.4 & 39.3 & 45.4 & 3.3 & 10.4 & 16.3 & 21.4 &27.3 & 34.4 & 40.3 & 46.4 & 4.5 & 9.6 & 15.5 & 22.6 & 28.5 33.6 & 39.5 &45.6 & 3.5 & 10.6 & 16.5 & 21.6 & 27.5 & 34.6 & 40.5 & 46.6 & U-;

[0052] The electrical connection mode of the single branch of the V-phase winding is:

[0053] V+ & 44.6 & 38.5 & 32.6 & 25.5 & 19.6 & 14.5 & 8.6 & 1.5 & 43.6 &37.5 & 31.6 & 26.5 & 20.6 & 13.5 & 7.6 & 2.5 & 44.4 & 38.3 & 32.4 & 25.3 &19.4 & 14.3 & 8.4 & 1.3 & 43.4 & 37.3 & 31.4 & 26.3 & 20.4 & 13.3 & 7.4 & 2.3& 44.2 & 38.1 & 32.2 & 25.1 & 19.2 & 14.1 & 8.2 & 1.1 & 43.2 & 37.1 & 31.2 & 26.1 & 20.2 & 13.1 & 7.2 & 2.1 & 8.1 & 13.2 & 19.1 & 26.2 & 32.1 & 37.2 & 43.1 & 1.2 & 7.1 & 14.2 & 20.1 & 25.2 & 31.1 & 38.2 & 44.1 & 2.2 & 8.3 & 13.4& 19.3 & 26.4 & 32.3 & 37.4 & 43.3 & 1.4 & 7.3 & 14.4 & 20.3 & 25.4 & 31.3 & 38.4 & 44.3 & 2.4 & 8.5 & 13.6 & 19.5 & 26.6 & 32.5 37.6 & 43.5 & 1.6 & 7.5& 14.6 & 20.5 & 25.6 & 31.5 & 38.6 & 44.5 & 2.6 & V-;

[0054] The electrical connection mode of the single branch of the W-phase winding is:

[0055] W+ & 48.6 & 42.5 & 36.6 & 29.5 & 23.6 & 18.5 & 12.6 & 5.5 & 47.6 &41.5 & 35.6 & 30.5 & 24.6 & 17.5 & 11.6 & 6.5 & 48.4 & 42.3 & 36.4 & 29.3 &23.4 & 18.3 & 12.4 & 5.3 & 47.4 & 41.3 & 35.4 & 30.3 & 24.4 & 17.3 & 11.4 &6.3 & 48.2 & 42.1 & 36.2 & 29.1 & 23.2 & 18.1 & 12.2 & 5.1 & 47.2 & 41.1 35.2 & 30.1 & 24.2 & 17.1 & 11.2 & 6.1 & 48.1 & 5.2 & 11.1 & 18.2 & 24.1 &29.2 & 35.1 & 41.2 & 47.1 & 6.2 & 12.1 & 17.2 & 23.1 & 30.2 & 36.1 & 42.2 &48.3 & 5.4 & 11.3 & 18.4 & 24.3 & 29.4 & 35.3 & 41.4 & 47.3 & 6.4 & 12.3 &17.4 & 23.3 & 30.4 & 36.3 & 42.4 & 48.5 & 5.6 & 11.5 & 18.6 24.5 & 29.6 &35.5 & 41.6 & 47.5 & 6.6 & 12.5 & 17.6 & 23.5 & 30.6 & 36.5 & 42.6 & W-.

[0056] Compared with the prior art, the advantages of the present invention are:

[0057] (1) The present invention can adopt a single-branch triangle wiring method. At the same time, without adjusting the above wiring method and adding a new type of U-shaped hairpin, it can be changed to a single-branch star wiring method. The triangle wiring method can output greater power and torque, and the star wiring method can reduce the power supply voltage requirement and starting current, reduce energy consumption, reduce insulation level requirements, and improve operating efficiency. In practical applications, a suitable wiring method can be selected based on actual needs. The above two wiring methods can be switched without incurring additional costs. At the same time, the switching is simple and the process is very easy to implement; the winding potentials under the above two wiring methods are balanced, and there is no circulating current problem. At the same time, the structure is simple, the lead wires are concentrated and there are no special-shaped wires, which is convenient for welding. At the same time, the wire package height can be very low. At the same time, this winding structure also has no I-type flat wire, only U-shaped hairpin type flat wire, and the required flat wire types are few, so the required corresponding molds are few, and then it has the advantage of low cost. At the same time, the process of the present invention has good manufacturability and is suitable for mass production.

[0058] (2) The present invention does not need to add a new type of U-shaped hairpin. It only needs to adjust the wiring form, that is, cancel the reverse U-shaped hairpin or use two reverse U-shaped hairpins for each phase, and add a neutral wire copper bar at the same time, so as to change the single-branch star wiring mode into a double-branch star wiring mode. The advantage of the double-branch winding is that it can increase the maximum torque of the motor, reduce the noise and vibration during the operation of the motor, and improve the NVH performance of the motor. In this double-branch star wiring mode, there is no circulating current problem in the potential balance, the lead wires and the neutral wires are concentrated and there are no special-shaped wires, and the process manufacturing is good, which is suitable for mass production.

[0059] (3) The flat wire U-shaped hairpin of the present invention adopts a cross-layer structure of two adjacent layers, and the flat wire U-shaped hairpin includes three pitch structures: full pitch Y1=m / 2p, long pitch Y2≥Y1+1, and short pitch Y3≤Y1-1. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A perspective view of the present invention;

[0061] Figure 2 It is a partially cutaway perspective view of the present invention;

[0062] Figure 3 This is a three-dimensional diagram of the initial state of the flat wire U-shaped hairpin of the present invention;

[0063] Figure 4 A three-dimensional diagram of the flat wire U-shaped hairpin in the first state of the present invention;

[0064] Figure 5 A three-dimensional diagram of the flat wire U-shaped hairpin in the second state of the present invention;

[0065] Figure 6It is a first winding expansion diagram of 8-pole 48-slot 6-layer in single-branch triangle connection mode in Example 2 of the present invention;

[0066] Figure 7 For the present invention Figure 6 Detailed diagram of

[0067] Figure 8 This is a schematic diagram of the structure of 6757 in Example 2 of the present invention;

[0068] Fig. 9 This is a schematic diagram of the structure of 6575 in Example 2 of the present invention;

[0069] Fig.10 It is an expanded diagram of the second winding of the 8-pole 48-slot 6-layer single-branch triangle connection mode in Example 3 of the present invention;

[0070] Fig.11 It is an expanded diagram of the third winding of the 8-pole 48-slot 6-layer single-branch triangle connection mode in Example 4 of the present invention;

[0071] Fig.12 It is an expanded diagram of the first winding of 10 poles, 60 slots and 6 layers in a single-branch triangle connection mode in Example 5 of the present invention;

[0072] Fig.13 It is an expanded diagram of the second winding of the 10-pole, 60-slot, 6-layer single-branch triangle connection mode in Example 6 of the present invention;

[0073] Fig.14 It is an expanded diagram of the third winding of the 10-pole, 60-slot, 6-layer single-branch triangle connection mode in Example 7 of the present invention;

[0074] Fig.15 This is a winding expansion diagram of 8 poles, 48 ​​slots and 6 layers in a single-branch star connection mode in Example 9 of the present invention;

[0075] Fig.16 It is an expanded diagram of the first winding of 8 poles, 48 ​​slots and 6 layers in a double-branch star connection mode in Example 10 of the present invention;

[0076] Fig.17 It is an expanded diagram of the second winding of the 8-pole 48-slot 6-layer double-branch star connection mode in Example 11 of the present invention;

[0077] Description of the numbers in the figure:

[0078] 100. stator core;

[0079] 200, insertion side;

[0080] 300, connection side;

[0081] 400, U-phase lead-out busbar hook;

[0082] 500, V-phase lead-out busbar hook;

[0083] 600, W phase lead-out busbar hook;

[0084] 700, flat wire U-shaped hairpin; 701, flat wire U-shaped hairpin body; 702, twisted section; 703, bent section. DETAILED DESCRIPTION

[0085] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the 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 them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0086] Example 1: Please refer to Figure 1 , a flat wire winding structure, comprising a stator core 100, wherein the upper and lower sides of the stator core 100 are respectively a flat wire connection side 300 and an insertion side 200, and a plurality of evenly distributed axial slots are opened on the inner side surface of the stator core 100 along the circumferential direction, the number of winding poles of the flat wire winding structure is 2p, the number of slots of the axial slots is m, each axial slot is provided with insulating paper and 2n layers of conductor, and along the axis direction of the stator core 100, from the outside to the inside, the 2nth layer, the 2n-1th layer, the 2n-2th layer, ..., the 1st layer are arranged in sequence, wherein: p≥4, n≥2, and p, m and n are all natural numbers;

[0087] See also Figure 1 and Figure 3 A flat wire U-shaped hairpin 700 is inserted into the axial slot, and the flat wire U-shaped hairpin 700 includes three pitch structures of full pitch Y1=m / 2p, long pitch Y2≥Y1+1, and short pitch Y3≤Y1-1, and Y2-Y3=m / 2p / 3, wherein: Y1, Y2, Y3 are all integers, and the pitch unit is "cross-slot";

[0088] See also Figure 3 In the initial state, the flat wire U-shaped hairpin 700 includes a flat wire U-shaped hairpin body 701, the bottom of the flat wire U-shaped hairpin body 701 is a twisted section 702 to form a cross-layer structure, and the two lead-out ends of the flat wire U-shaped hairpin body 701 in the initial state are straight line segments. The flat wire U-shaped hairpin 700 in the initial state is inserted through the insertion side 200 as a whole, and is led out at the connection side 300, and then two bent sections 703 are obtained by twisting and bending, and then electrical connection is achieved with other twisted and bent flat wire U-shaped hairpins 700;

[0089] In this embodiment: the flat wire U-shaped hairpin 700 is inserted through the insertion side 200 and twisted and bent, and then the electrical connection is achieved at the connection side 300, and finally a three-phase winding of the flat wire winding structure is formed: U-phase winding, V-phase winding and W-phase winding, and the lead wire ends of the U-phase winding, V-phase winding and W-phase winding are arranged at the connection side 300;

[0090] See also Figure 6 , the flat wire winding structure can adopt a single-branch triangle connection method, where:

[0091] W- is connected to U+ as the lead-out terminal of the U-phase winding;

[0092] U- is connected to V+ as the lead-out terminal of the V-phase winding;

[0093] V- is connected to W+ as the lead-out terminal of the W phase winding;

[0094] See also Figure 1 The flat wire U-shaped hairpin 700 adopts a cross-layer electrical connection structure between two adjacent layers. Specifically, the cross-layer electrical connection structure between two adjacent layers includes:

[0095] Reverse cross-layer electrical connection structure of 2n to 2n-1 layer, 2n-2 to 2n-3 layer, ..., 2 to 1 layer;

[0096] A forward cross-layer electrical connection structure of 1 to 2 layers, ..., 2n-3 to 2n-2 layers, 2n-1 to 2n layers;

[0097] It should be noted that the above “two adjacent layers” refer to two adjacent layers in different axial slots, and do not refer to two adjacent sides in the same axial slot, such as:

[0098] For a U-shaped hairpin with a pitch of 6 cross slots, the 6th layer in the 40th axial slot spans to the 5th layer in the 34th axial slot. The 6th layer and the 5th layer are constructed as "two adjacent layers", which is a reverse cross-layer electrical connection structure; another example:

[0099] The U-shaped hairpin with a pitch of 6 cross slots spans from the 5th layer in the 36th axial slot to the 6th layer in the 42nd axial slot. The 5th layer and the 6th layer are constructed as "two adjacent layers", which is a forward cross-layer electrical connection structure.

[0100] Please continue reading Figure 1 , this embodiment further includes a U-phase lead bus hook 400, a V-phase lead bus hook 500 and a W-phase lead bus hook 600 provided on the connection side 300, the U-phase lead bus hook 400 is connected to U+ and then led out, the V-phase lead bus hook 500 is connected to U- and V+ and then led out, and the W-phase lead bus hook 600 is connected to V- and W+ and then led out;

[0101] See also Figure 1 , Figure 4 and Figure 5 After the flat wire U-shaped hairpin body 701 is inserted into the axial slot, it is bent and twisted to obtain two bending sections 703. The two bending sections 703 have a first state and a second state, wherein:

[0102] See also Figure 4 , the first state is: the two bending sections 703 are bent in opposite directions;

[0103] See also Figure 5 , the second state is: the two bending sections 703 have the same bending direction;

[0104] It should be noted that: in each phase winding single branch, the flat wire U-shaped hairpin 700 in the second state is used only once, and the hairpin is used only when the connection of the electrical fold is changed from reverse cross-layer to forward cross-layer, and the flat wire U-shaped hairpin 700 in the first state is used in the remaining cases, which is described in detail in Example 2.

[0105] Specifically: the flat wire winding structure includes any one of 8-pole 48 slots, 10-pole 60 slots, 12-pole 72 slots and 16-pole 96 slots, and each axial slot is provided with any one of 4 layers, 6 layers, 8 layers, 10 layers and 12 layers of conductors;

[0106] Example 2: Please refer to Figure 2 This embodiment is based on the first embodiment and takes the flat wire winding with 8 poles and 48 slots as an example to explain in detail:

[0107] The flat wire winding structure is 8 poles and 48 slots. The number of winding poles of the flat wire winding structure is 8, the number of axial slots is 48, and each axial slot is provided with 6 layers of conductors. Therefore, it can be known that 2p=8, m=48, 2n=6. After calculation, it is obtained that: p=4, m=48, n=3;

[0108] Substituting p=4, m=48, n=3 into Y1=m / 2p, Y2≥Y1+1, Y3≤Y1-1, Y2-Y3=m / 2p / 3, it is calculated that the full pitch Y1 of the flat wire U-shaped hairpin 700 is 6 slots, the long pitch Y2 is 7 slots, and the short pitch Y3 is 5 slots;

[0109] Therefore, the flat wire U-shaped hairpin 700 adopts a reverse cross-layer electrical connection structure of 6 to 5 layers, 4 to 3 layers, and 2 to 1 layer, and a forward cross-layer electrical connection structure of 1 to 2 layers, 3 to 4 layers, and 5 to 6 layers;

[0110] See also Figure 6 and Figure 7 , in one branch of the U-phase winding:

[0111] When the flat wire U-shaped hairpin 700 adopts a reverse cross-layer electrical connection structure of 6 turns to 5 layers, the pitches are 6, 7, 5, 7, 6, 5, 7, 5 in sequence, and the method is recorded as "6757 6575 (6 turns to 5 layers)";

[0112] When the flat wire U-shaped hairpin 700 adopts a reverse cross-layer electrical connection structure of 4 turns to 3 layers, the pitches are 6, 7, 5, 7, 6, 5, 7, 5 in sequence, and the method is recorded as "6757 6575 (4 turns to 3 layers)";

[0113] When the flat wire U-shaped hairpin 700 adopts a reverse cross-layer electrical connection structure of 2 turns to 1 layer, the pitches are 6, 7, 5, 7, 6, 5, 7, 5 in sequence, and the method is recorded as "6757 6575 (2 turns to 1 layer)";

[0114] When the flat wire U-shaped hairpin 700 adopts a 1-to-2-layer forward cross-layer electrical connection structure, the pitches are 5, 7, 5, 6, 7, 5, 7, 6 in sequence, and the method is recorded as "5756 7576 (1-to-2 layers)";

[0115] When the flat wire U-shaped hairpin 700 adopts a 3-to-4-layer forward cross-layer electrical connection structure, the pitches are 5, 7, 5, 6, 7, 5, 7, 6 in sequence, and the method is recorded as "5756 7576 (3-to-4 layers)".

[0116] When the flat wire U-shaped hairpin 700 adopts a 5-to-6-layer forward cross-layer electrical connection structure, the pitches are 5, 7, 5, 6, 7, 5, 7, 6 in sequence, and the method is recorded as "5756 7576 (5-to-6 layers)";

[0117] Based on the above records, Figure 7 In the state shown, the present invention adopts the following method:

[0118] A. 6757 6575 (6 to 5 layers); 6757 6575 (4 to 3 layers); 6757 6575 (2 to 1 layer), this is a reverse cross-layer electrical connection structure, among which: 5, 6, and 7 are the three pitches of the flat wire U-shaped hairpin 700;

[0119] B. 5756 7576 (1 to 2 layers); 5756 7576 (3 to 4 layers); 5756 7576 (5 to 6 layers), this is a forward cross-layer electrical connection structure, where 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0120] For the sake of Figure 7 To elaborate:

[0121] This embodiment takes "6757 (6 to 5 layers)" in "6757 6575 (6 to 5 layers)" as an example to explain in detail:

[0122] See also Figure 7 and Figure 8 , 6757 (6 to 5 layers) uses the flat wire U-shaped hairpin 700 with a pitch of 6 slots, the flat wire U-shaped hairpin 700 with a pitch of 7 slots, the flat wire U-shaped hairpin 700 with a pitch of 5 slots, and the flat wire U-shaped hairpin 700 with a pitch of 7 slots. Among them, the flat wire U-shaped hairpin 700 with a pitch of 7 slots and the flat wire U-shaped hairpin 700 with a pitch of 7 slots have the same specifications. Figure 4 as well as Figure 8 It can be seen that the bending section 703 has three span grooves. In this embodiment, the bending section 703 has three span grooves. Figure 8 The flat wire U-shaped hairpin 700 in the shown states are all in the first state;

[0123] This embodiment takes "6575 (2 transfer to 1 floor)" in "6757 6575 (2 transfer to 1 floor)" as an example to explain in detail:

[0124] See also Figure 7 and Fig. 9 , 6575 (2 to 1 layer) uses the flat wire U-shaped hairpin 700 with a pitch of 6 slots, the flat wire U-shaped hairpin 700 with a pitch of 5 slots, the flat wire U-shaped hairpin 700 with a pitch of 7 slots, and the flat wire U-shaped hairpin 700 with a pitch of 5 slots. Among them, the flat wire U-shaped hairpin 700 with a pitch of 5 slots and the flat wire U-shaped hairpin 700 with a pitch of 5 slots have the same specifications. Fig. 9 The No.⑧ flat wire U-shaped hairpin 700 in the shown state is in the second state;

[0125] The above case is based on a branch of the U-phase winding as an example. In one path of the U-phase winding, there is only one flat wire U-shaped hairpin 700 in the second state, which serves as a reverse folded hairpin. Similarly, in one path of the V-phase winding and the W-phase winding, there is only one reverse folded hairpin.

[0126] It should also be noted that: no matter it is 6 turns 5 layers or 5 turns 6 layers, as long as the pitch is the same, the specifications of the flat wire U-shaped hairpin 700 are the same, that is, the flat wire U-shaped hairpin 700 of 6 turns 5 layers and a pitch of 7 cross slots is the same as the flat wire U-shaped hairpin 700 of 5 turns 6 layers and a pitch of 7 cross slots;

[0127] However, even if the pitches of 6-turn 5-layer and 4-turn 3-layer are the same, the flat wire U-shaped hairpin 700 adopts different specifications, that is, although the number of cross slots is the same, the spacing is different, that is, the flat wire U-shaped hairpin 700 of 6-turn 5-layer and the pitch of 7 cross slots is different from the flat wire U-shaped hairpin 700 of 4-turn 3-layer and the pitch of 7 cross slots;

[0128] Similarly, it can be known that no matter it is 4 turns to 3 layers or 3 turns to 4 layers, as long as the pitch is the same, the specifications of the flat wire U-shaped hairpin 700 are the same, that is, the flat wire U-shaped hairpin 700 of 4 turns to 3 layers and the pitch is 7 cross slots is the same as the flat wire U-shaped hairpin 700 of 3 turns to 4 layers and the pitch is 7 cross slots;

[0129] The principles of 2 to 1 layer and 1 to 2 layers are the same as above, so I will not repeat them here;

[0130] “ & ” represents the connection part between two flat wire U-shaped hairpins 700 , and “ij” represents the jth layer in the i-th axial slot;

[0131] The electrical connection method of the U-phase winding branch is:

[0132] U+ & 40.6 & 34.5 & 28.6 & 21.5 & 15.6 & 10.5 & 4.6 & 45.5 & 39.6 &33.5 & 27.6 & 22.5 & 16.6 & 9.5 & 3.6 & 46.5 & 40.4 & 34.3 & 28.4 & 21.3 &15.4 & 10.3 & 4.4 & 45.3 & 39.4 & 33.3 & 27.4 & 22.3 & 16.4 & 9.3 & 3.4 &46.3 & 40.2 & 34.1 & 28.2 & 21.1 & 15.2 & 10.1 & 4.2 & 45.1 & 39.2 & 33.1 3.4 & 39.3 & 45.4 & 3.3 & 10.4 & 16.3 & 21.4 &27.3 & 34.4 & 40.3 & 46.4 & 4.5 & 9.6 & 15.5 & 22.6 & 28.5 & 3.1 & 10.2 & 16.1 & 21.2 & 27.1 & 34.2 & 40.1 & 46.2 & 4.3 &9.4 & 15.3 & 22.4 & 28.3 & 33.4 & 39.3 & 45.4 & 3.3 & 10.4 & 16.3 & 21.4 &27.3 & 34.4 & 40.3 & 46.4 & 4.5 & 9.6 & 15.5 & 22.6 & 28.5 33.6 & 39.5 &45.6 & 3.5 & 10.6 & 16.5 & 21.6 & 27.5 & 34.6 & 40.5 & 46.6 & U-;

[0133] The electrical connection method of the V-phase winding branch is:

[0134] V+ & 44.6 & 38.5 & 32.6 & 25.5 & 19.6 & 14.5 & 8.6 & 1.5 & 43.6 &37.5 & 31.6 & 26.5 & 20.6 & 13.5 & 7.6 & 2.5 & 44.4 & 38.3 & 32.4 & 25.3 &19.4 & 14.3 & 8.4 & 1.3 & 43.4 & 37.3 & 31.4 & 26.3 & 20.4 & 13.3 & 7.4 & 2.3& 44.2 & 38.1 & 32.2 & 25.1 & 19.2 & 14.1 & 8.2 & 1.1 & 43.2 & 37.1 & 31.2 & 26.1 & 20.2 & 13.1 & 7.2 & 2.1 & 8.1 & 13.2 & 19.1 & 26.2 & 32.1 & 37.2 & 43.1 & 1.2 & 7.1 & 14.2 & 20.1 & 25.2 & 31.1 & 38.2 & 44.1 & 2.2 & 8.3 & 13.4& 19.3 & 26.4 & 32.3 & 37.4 & 43.3 & 1.4 & 7.3 & 14.4 & 20.3 & 25.4 & 31.3 & 38.4 & 44.3 & 2.4 & 8.5 & 13.6 & 19.5 & 26.6 & 32.5 37.6 & 43.5 & 1.6 & 7.5& 14.6 & 20.5 & 25.6 & 31.5 & 38.6 & 44.5 & 2.6 & V-;

[0135] The electrical connection method of the W-phase winding branch is:

[0136] W+ & 48.6 & 42.5 & 36.6 & 29.5 & 23.6 & 18.5 & 12.6 & 5.5 & 47.6 &41.5 & 35.6 & 30.5 & 24.6 & 17.5 & 11.6 & 6.5 & 48.4 & 42.3 & 36.4 & 29.3 &23.4 & 18.3 & 12.4 & 5.3 & 47.4 & 41.3 & 35.4 & 30.3 & 24.4 & 17.3 & 11.4 &6.3 & 48.2 & 42.1 & 36.2 & 29.1 & 23.2 & 18.1 & 12.2 & 5.1 & 47.2 & 41.1 35.2 & 30.1 & 24.2 & 17.1 & 11.2 & 6.1 & 48.1 & 5.2 & 11.1 & 18.2 & 24.1 &29.2 & 35.1 & 41.2 & 47.1 & 6.2 & 12.1 & 17.2 & 23.1 & 30.2 & 36.1 & 42.2 &48.3 & 5.4 & 11.3 & 18.4 & 24.3 & 29.4 & 35.3 & 41.4 & 47.3 & 6.4 & 12.3 &17.4 & 23.3 & 30.4 & 36.3 & 42.4 & 48.5 & 5.6 & 11.5 & 18.6 24.5 & 29.6 &35.5 & 41.6 & 47.5 & 6.6 & 12.5 & 17.6 & 23.5 & 30.6 & 36.5 & 42.6 & W-;

[0137] Example 3: Please refer to Fig.10 This embodiment provides a flat wire winding structure with 8 poles, 48 ​​slots and 6 conductor layers. Fig.10 The second winding expansion diagram under the single-branch triangle connection method:

[0138] exist Fig.10 In the state shown, the present invention adopts the following method:

[0139] A. 6575 6757 (6 to 5 layers); 6575 6757 (4 to 3 layers); 6575 6757 (2 to 1 layer), this is a reverse cross-layer electrical connection structure, among which: 5, 6, and 7 are the three pitches of the flat wire U-shaped hairpin 700;

[0140] B. 7576 5756 (1 to 2 layers); 7576 5756 (3 to 4 layers); 7576 5756 (5 to 6 layers), this is a forward cross-layer electrical connection structure, where 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0141] This embodiment is based on Example 2. Figure 7 and Fig.10 It can be seen that:

[0142] When 6 turns to 5 layers and 4 turns to 3 layers, the pitch changes from 6757 6575 to 6575 6757; when 2 turns to 1 layer, the pitch changes from 6757 6575 (5 is folded here) to 6575 6757 (7 is folded here); when 1 turns to 2 layers, 3 turns to 4 layers and 5 turns to 6 layers, the pitch changes from 5756 7576 to 7576 5756; that is, this embodiment is based on the embodiment 2, and a new electrical connection method is formed by changing 5 spans to 7 spans and 7 spans to 5 spans;

[0143] Example 4: Please refer to Fig.11 This embodiment provides a flat wire winding structure with 8 poles, 48 ​​slots and 6 conductor layers. Fig.11 The third winding expansion diagram under the single-branch triangle connection method:

[0144] exist Fig.11 In the state shown, the present invention adopts the following method:

[0145] A. 6667 6665 (6 to 5 layers); 6667 6665 (4 to 3 layers); 6667 6665 (2 to 1 layer), this is a reverse cross-layer electrical connection structure, among which: 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0146] B. 5666 7666 (1 to 2 layers); 5666 7666 (3 to 4 layers); 5666 7666 (5 to 6 layers), this is a forward cross-layer electrical connection structure, where 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0147] contrast Figure 7 and Fig.11 It can be seen that: Example 4 is a new electrical connection method formed by replacing the adjacent 7-span and 5-span flat wire U-shaped hairpins in Example 2 with two 6-span flat wire U-shaped hairpins. Similarly, Example 3 can also replace the flat wire U-shaped hairpins in the same way to form a fourth electrical connection method, so it will not be repeated;

[0148] Example 5: Please refer to Fig.12 This embodiment provides a flat wire winding structure with 10 poles, 60 slots and 6 conductor layers. Fig.12This is the first winding expansion diagram under the single-branch delta connection method:

[0149] exist Fig.12 In the state shown, the present invention adopts the following method:

[0150] A. 66757 66575 (6 to 5 layers); 66757 66575 (4 to 3 layers); 66757 66575 (2 to 1 layer), this is a reverse cross-layer electrical connection structure, among which: 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0151] B. 57566 75766 (1 to 2 layers); 57566 75766 (3 to 4 layers); 57566 75766 (5 to 6 layers), this is a forward cross-layer electrical connection structure, where 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0152] This embodiment is based on Example 2. Figure 7 and Fig.12 It can be seen that:

[0153] When 6 turns to 5 layers, 4 turns to 3 layers, and 2 turns to 1 layer, the pitch changes from 6757 6575 to 66757 66575; when 1 turns to 2 layers, 3 turns to 4 layers, and 5 turns to 6 layers, the pitch changes from 5756 7576 to 57566 75766; that is, the electrical connection method formed by increasing the number of 6-slot U-shaped hairpins on the basis of Example 2 in this embodiment;

[0154] Similarly, both 12 poles and 72 slots and 16 poles and 96 slots can be electrically connected by increasing the number of 6-slot U-shaped hairpins in embodiments 2, 3 and 4, so they will not be described in detail.

[0155] Example 6: Please refer to Fig.13 This embodiment provides a flat wire winding structure with 10 poles, 60 slots and 6 conductor layers. Fig.13 The second winding expansion diagram under the single-branch triangle connection method:

[0156] exist Fig.13 In the state shown, the present invention adopts the following method:

[0157] A. 66575 66757 (6 to 5 layers); 66575 66757 (4 to 3 layers); 66575 66757 (2 to 1 layer), this is a reverse cross-layer electrical connection structure, among which: 5, 6, and 7 are the three pitches of the flat wire U-shaped hairpin 700;

[0158] B. 75766 57566 (1 to 2 layers); 75766 57566 (3 to 4 layers); 75766 57566 (5 to 6 layers), this is a forward cross-layer electrical connection structure, where 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0159] This embodiment is based on Example 5. Fig.12 and Fig.13 It can be seen that:

[0160] When 6 turns to 5 layers and 4 turns to 3 layers, the pitch changes from 66757 66575 to 66575 66757; when 2 turns to 1 layer, the pitch changes from 66757 66575 (5 is folded here) to 66575 66757 (7 is folded here); when 1 turns to 2 layers, 3 turns to 4 layers and 5 turns to 6 layers, the pitch changes from 57566 75766 to 75766 57566;

[0161] Similarly, 12 poles 72 slots and 16 poles 96 slots can also form a new electrical connection method by changing 5 spans to 7 spans and 7 spans to 5 spans, so it will not be repeated here.

[0162] Example 7: Please refer to Fig.14 This embodiment provides a flat wire winding structure with 10 poles, 60 slots and 6 conductor layers. Fig.14 The third winding expansion diagram under the single-branch triangle connection method:

[0163] exist Fig.14 In the state shown, the present invention adopts the following method:

[0164] A. 66667 66665 (6 to 5 layers); 66667 66665 (4 to 3 layers); 66667 66665 (2 to 1 layer), this is a reverse cross-layer electrical connection structure, among which: 5, 6, 7 are three pitches of the flat wire U-shaped hairpin 700;

[0165] B. 56666 76666 (1 to 2 layers); 56666 76666 (3 to 4 layers); 56666 76666 (5 to 6 layers), this is a forward cross-layer electrical connection structure, where 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0166] Embodiment 7 is a new electrical connection method formed by replacing the adjacent 7-slot and 5-slot flat wire U-shaped hairpins in Embodiment 5 with two 6-slot flat wire U-shaped hairpins. Similarly, Embodiment 6 and 12-pole 72-slot and 16-pole 96-slot can also form a new electrical connection method in the same way, so it will not be repeated;

[0167] Embodiment 8: The above embodiments are all from 6 to 5 layers as the initial starting point, that is, the above embodiments are all from the outermost layer to insert the flat wire U-shaped hairpin 700, and the lead wire is on the outermost side, and vice versa, that is, this embodiment can be from 1 to 2 layers as the initial starting point, and the technical solution of this embodiment can be obtained by reversing the above embodiments, that is, this embodiment inserts the flat wire U-shaped hairpin 700 from the innermost layer, and the lead wire is on the innermost side;

[0168] Example 9: Please refer to Fig.15 The above embodiments are all single-branch triangle wiring methods. This embodiment does not change the above wiring form and does not add a new type of U-shaped hairpin. It only needs to change the lead-out method in the above embodiments: W- and U+ are connected as the U-phase winding lead-out terminal; U- and V+ are connected as the V-phase winding lead-out terminal;

[0169] V- is connected with W+ as the lead-out terminal of the W phase winding, and U+ is used as the lead-out terminal of the U phase winding; V+ is used as the lead-out terminal of the V phase winding; W+ is used as the lead-out terminal of the W phase winding;

[0170] At the same time, U-, V- and W- are connected together as the star connection neutral point to form a single-branch star connection mode;

[0171] Example 10: Please refer to Fig.16 This embodiment provides a flat wire winding structure with 8 poles, 48 ​​slots and 6 conductor layers. Fig.16 This is the first winding expansion diagram under the double-branch star connection method:

[0172] exist Fig.16 In the state shown, the present invention adopts the following method:

[0173] A. 6757 6575 (6 turns to 5 layers); 6757 6575 (4 turns to 3 layers); 6757 6575 (2 turns to 1 layer), this is a 1-branch electrical connection structure, among which: 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0174] B. 6575 6757 (5 to 6 layers); 6575 6757 (3 to 4 layers); 6575 6757 (1 to 2 layers). This is a 2-branch electrical connection structure, where 5, 6, and 7 are the three pitches of the flat wire U-shaped hairpin 700; 1 branch and 2 branches exist independently of each other. Fig.15 and Fig.16, based on Example 9, this embodiment only needs to adjust the wiring form, that is, cancel the reverse U-shaped hairpin method without adding a new type of U-shaped hairpin, and at the same time add a neutral copper bar to change the single-branch star wiring method into a double-branch star wiring method, that is, U1+ and U2+ are connected together as the U-phase winding lead-out terminal; V1+ and V2+ are connected together as the V-phase winding lead-out terminal; W1+ and W2+ are connected together as the W-phase winding lead-out terminal; U1-, U2-, V1-, V2-, W1- and W2- are connected to the neutral copper bar and serve as the neutral line of the double-branch star wiring; similarly, 10-level 60 slots, 12-pole 72 slots and 16-pole 96 slots can also form a new electrical connection method in the same way, so it will not be repeated;

[0175] Example 11: Please refer to Fig.17 This embodiment provides a flat wire winding structure with 8 poles, 48 ​​slots and 6 conductor layers. Fig.17 The second winding expansion diagram under the double-branch star connection method:

[0176] exist Fig.17 In the state shown, the present invention adopts the following method:

[0177] A. 6675 (6 to 5 layers); 6675 (4 to 3 layers); 6675 (2 to 1 layer); 5766 (1 to 2 layers); 5766 (3 to 4 layers); 5766 (5 to 6 layers), this is a 1-branch electrical connection structure, where 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700;

[0178] B. 6657 (6 to 5 layers); 6657 (4 to 3 layers); 6657 (2 to 1 layer); 7566 (1 to 2 layers); 7566 (3 to 4 layers); 7566 (5 to 6 layers), this is a 2-branch electrical connection structure, where 5, 6, and 7 are three pitches of the flat wire U-shaped hairpin 700; branch 1 and branch 2 exist independently of each other;

[0179] contrast Fig.15 and Fig.17, based on Example 9, this embodiment only needs to adjust the wiring form without adding a new type of U-shaped hairpin, that is, using two reverse U-shaped hairpins for each phase, and adding a neutral copper bar to change the single-branch star wiring mode into a double-branch star wiring mode, that is, U1+ and U2+ are connected together as the U-phase winding lead-out terminal; V1+ and V2+ are connected together as the V-phase winding lead-out terminal; W1+ and W2+ are connected together as the W-phase winding lead-out terminal; U1-, U2-, V1-, V2-, W1- and W2- are connected to the neutral copper bar and serve as the double-branch star wiring neutral line; similarly, 10-level 60 slots, 12-pole 72 slots and 16-pole 96 slots can also form a new electrical connection mode in the same way, so it will not be repeated;

[0180] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and improved concepts of the present invention within the technical scope disclosed by the present invention, and they should be covered by the protection scope of the present invention.

Claims

1. A flat wire winding structure, comprising a stator core (100), wherein the upper and lower sides of the stator core (100) are respectively a connection side (300) and an insertion side (200) of the flat wire, and a plurality of evenly distributed axial slots are provided on the inner side surface of the stator core (100) along the circumferential direction, wherein: The number of winding poles of the flat wire winding structure is 2p, the number of slots of the axial slots is m, each of the axial slots is provided with insulating paper and 2n layers of conductors, and along the axis direction of the stator core (100), from the outside to the inside, the 2nth layer, the 2n-1st layer, the 2n-2nd layer, ..., the 1st layer, wherein: p≥4, n≥2, and p, m and n are all natural numbers; A flat wire U-shaped hairpin (700) is inserted into the axial slot, and the flat wire U-shaped hairpin (700) comprises three pitch structures: full pitch Y1=m / 2p, long pitch Y2≥Y1+1, and short pitch Y3≤Y1-1, and Y2-Y3=m / 2p / 3, wherein: Y1, Y2, Y3 are all integers, and the pitch unit is "cross-slot"; The flat wire U-shaped hairpin (700) adopts a cross-layer structure of two adjacent layers; The flat wire U-shaped hairpin (700) is inserted through the insertion side (200) and is then electrically connected to the connection side (300) by twisting and bending, thereby finally forming a three-phase winding of the flat wire winding structure: a U-phase winding, a V-phase winding, and a W-phase winding, wherein the lead-out wire ends of the U-phase winding, the V-phase winding, and the W-phase winding are arranged on the connection side (300); The flat wire winding structure adopts a single-branch delta connection mode, a single-branch star connection mode, or a double-branch star connection mode; When the flat wire winding structure adopts a single-branch delta connection method: W- is connected to U+ as the lead-out terminal of the U-phase winding; U- is connected to V+ as the lead-out terminal of the V-phase winding; V- is connected to W+ as the lead-out terminal of the W-phase winding; When the flat wire winding structure adopts a single-branch star connection mode, it is not necessary to adjust the wiring mode and to add a flat wire U-shaped hairpin (700), wherein: U+ is used as the lead-out terminal of the U-phase winding; V+ is used as the lead-out terminal of the V-phase winding; W+ is used as the lead-out terminal of the W-phase winding; U-, V- and W- are connected together as the star connection neutral point; When the flat wire winding structure adopts a double-branch star connection mode, it is not necessary to increase the type of flat wire U-shaped hairpin (700), but the wiring form needs to be adjusted, that is, the reverse U-shaped hairpin is cancelled or two reverse U-shaped hairpins are used for each phase, and a neutral copper bar needs to be added, wherein: U1+ and U2+ are connected together to serve as the U-phase winding lead-out terminal; V1+ and V2+ are connected together to serve as the V-phase winding lead-out terminal; W1+ and W2+ are connected together to serve as the W-phase winding lead-out terminal; U1-, U2-, V1-, V2-, W1- and W2- are connected to the neutral copper busbar and serve as the double-branch star-connected neutral line; The cross-layer structure of two adjacent layers includes: A reverse cross-layer structure of 2n to 2n-1 layers, 2n-2 to 2n-3 layers, ..., 2 to 1 layer; and 1 turns to 2 layers, ..., 2n-3 turns to 2n-2 layers, 2n-1 turns to 2n layers in a forward cross-layer structure; The flat wire U-shaped hairpin (700) comprises a flat wire U-shaped hairpin body (701), the bottom of the flat wire U-shaped hairpin body (701) is a twisted section (702) forming a cross-layer structure, and after the flat wire U-shaped hairpin body (701) is inserted into an axial slot, it is twisted and bent to obtain two bent sections (703), and the two bent sections (703) have a first state and a second state, wherein: The first state is: the two bending sections (703) are bent in opposite directions; The second state is: the two bending sections (703) have the same bending direction; The flat wire winding structure includes any one of 8 poles and 48 slots, 10 poles and 60 slots, 12 poles and 72 slots, and 16 poles and 96 slots, and each of the axial slots is provided with any one of 4 layers, 6 layers, 8 layers, 10 layers, and 12 layers of conductors; The flat wire winding structure is 8 poles and 48 slots. The number of winding poles of the flat wire winding structure is 8, the number of slots of the axial slots is 48, and each of the axial slots is provided with 6 layers of conductors. After calculation, it is obtained that: p=4, m=48, n=3; Substituting p=4, m=48, n=3 into Y1=m / 2p, Y2≥Y1+1, Y3≤Y1-1, Y2-Y3=m / 2p / 3, it is calculated that the full pitch Y1 of the flat wire U-shaped hairpin (700) is 6 slots, the long pitch Y2 is 7 slots, and the short pitch Y3 is 5 slots; The flat wire U-shaped hairpin (700) adopts: 6 to 5 layers, 4 to 3 layers, 2 to 1 layer reverse cross-layer structure; and The forward cross-layer structure of 1 to 2 layers, 3 to 4 layers, 5 to 6 layers; In one branch of the U-phase winding: When the flat wire U-shaped hairpin (700) adopts a 6-to-5-layer reverse cross-layer structure, the pitches are 6, 7, 5, 7, 6, 5, 7, 5 in sequence; When the flat wire U-shaped hairpin (700) adopts a 4-to-3-layer reverse cross-layer structure, the pitches are 6, 7, 5, 7, 6, 5, 7, 5 in sequence; When the flat wire U-shaped hairpin (700) adopts a 2-to-1-layer reverse cross-layer structure, the pitches thereof are 6, 7, 5, 7, 6, 5, 7, 5 in sequence; When the flat wire U-shaped hairpin (700) adopts a 1-to-2-layer forward cross-layer structure, the pitches thereof are 5, 7, 5, 6, 7, 5, 7, 6 in sequence; When the flat wire U-shaped hairpin (700) adopts a 3-to-4-layer forward cross-layer structure, the pitches thereof are 5, 7, 5, 6, 7, 5, 7, 6 in sequence; When the flat wire U-shaped hairpin (700) adopts a 5-turn 6-layer forward cross-layer structure, its pitches are 5, 7, 5, 6, 7, 5, 7, 6 in sequence.

2. A flat wire winding structure according to claim 1, characterized in that: "&" represents the connection part between two flat wire U-shaped hairpins (700), and "ij" represents the jth layer in the i-th axial slot, then: The electrical connection mode of the single branch of the U-phase winding is: U+ & 40.6 & 34.5 & 28.6 & 21.5 & 15.6 & 10.5 & 4.6 & 45.5 & 39.6 & 33.5 &27.6 & 22.5 & 16.6 & 9.5 & 3.6 & 46.5 & 40.4 & 34.3 & 28.4 & 21.3 & 15.4 &10.3 & 4.4 & 45.3 & 39.4 & 33.3 & 27.4 & 22.3 & 16.4 & 9.3 & 3.4 & 46.3 &40.2 & 34.1 & 28.2 & 21.1 & 15.2 & 10.1 & 4.2 & 45.1 & 39.2 & 33.1 & 27.2 &22.1 & 16.2 & 9.1 & 3.2 & 46.1 & 4.1 & 9.2 & 15.1 & 22.2 & 28.1 & 33.2 & 39.1& 45.2 & 3.1 & 10.2 & 16.1 & 21.2 & 27.1 & 34.2 & 40.1 & 46.2 & 4.3 & 9.4 &15.3 & 22.4 & 28.3 & 33.4 & 39.3 & 45.4 & 3.3 & 10.4 & 16.3 & 21.4 & 27.3 &34.4 & 40.3 & 46.4 & 4.5 & 9.6 & 15.5 & 22.6 & 28.5 33.6 & 39.5 & 45.6 &3.5 & 10.6 & 16.5 & 21.6 & 27.5 & 34.6 & 40.5 & 46.6 & U-; The electrical connection mode of the single branch of the V-phase winding is: V+ & 44.6 & 38.5 & 32.6 & 25.5 & 19.6 & 14.5 & 8.6 & 1.5 & 43.6 & 37.5 &31.6 & 26.5 & 20.6 & 13.5 & 7.6 & 2.5 & 44.4 & 38.3 & 32.4 & 25.3 & 19.4 &14.3 & 8.4 & 1.3 & 43.4 & 37.3 & 31.4 & 26.3 & 20.4 & 13.3 & 7.4 & 2.3 & 44.2& 38.1 & 32.2 & 25.1 & 19.2 & 14.1 & 8.2 & 1.1 & 43.2 & 37.1 & 31.2 & 26.1 &20.2 & 13.1 & 7.2 & 2.1 & 8.1 & 13.2 & 19.1 & 26.2 & 32.1 & 37.2 & 43.1 & 1.2 & 7.1 & 14.2 & 20.1 & 25.2 & 31.1 & 38.2 & 44.1 & 2.2 & 8.3 & 13.4 & 19.3 &26.4 & 32.3 & 37.4 & 43.3 & 1.4 & 7.3 & 14.4 & 20.3 & 25.4 & 31.3 & 38.4 &44.3 & 2.4 & 8.5 & 13.6 & 19.5 & 26.6 & 32.5 & 37.6 & 43.5 & 1.6 & 7.5 & 14.6& 20.5 & 25.6 & 31.5 & 38.6 & 44.5 & 2.6 & V-; The electrical connection mode of the single branch of the W-phase winding is: W+ & 48.6 & 42.5 & 36.6 & 29.5 & 23.6 & 18.5 & 12.6 & 5.5 & 47.6 & 41.5 &35.6 & 30.5 & 24.6 & 17.5 & 11.6 & 6.5 & 48.4 & 42.3 & 36.4 & 29.3 & 23.4 &18.3 & 12.4 & 5.3 & 47.4 & 41.3 & 35.4 & 30.3 & 24.4 & 17.3 & 11.4 & 6.3 &48.2 & 42.1 & 36.2 & 29.1 & 23.2 & 18.1 & 12.2 & 5.1 & 47.2 & 41.1 & 35.2 &30.1 & 24.2 & 17.1 & 11.2 & 6.1 & 48.1 & 5.2 & 11.1 & 18.2 & 24.1 & 29.2 &35.1 & 41.2 & 47.1 & 6.2 & 12.1 & 17.2 & 23.1 & 30.2 & 36.1 & 42.2 & 48.3 &5.4 & 11.3 & 18.4 & 24.3 & 29.4 & 35.3 & 41.4 & 47.3 & 6.4 & 12.3 & 17.4 &23.3 & 30.4 & 36.3 & 42.4 & 48.5 & 5.6 & 11.5 & 18.6 & 24.5 & 29.6 & 35.5 &41.6 & 47.5 & 6.6 & 12.5 & 17.6 & 23.5 & 30.6 & 36.5 & 42.6 & W-。

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