Flat wire motor stator winding structure and winding method thereof

Abstract

The application discloses a flat wire motor stator winding structure and a winding method thereof. The structure comprises a stator core, 54 stator slots and a flat wire conductor group inserted into each stator slot. The flat wire conductor group is radially stacked into four conductor layers in each stator slot. The flat wire conductor group is connected by hairpin conductors at the crown end of the stator core to form a three-phase winding. The hairpin conductors arranged at the crown end are distributed into six hairpin groups in the circumferential and radial directions, and the six hairpin groups have different span specifications. The end portions of the flat wire conductors are twisted and welded at the welding end of the stator core. The span of the twisted head is 4.5 stator slot distances. The outgoing lines of the U-phase winding, the V-phase winding and the W-phase winding are concentratedly led out in the circumferential same phase area at the crown end. The flat wire motor stator winding structure and the winding method thereof reduce the hairpin types, simplify the winding process and busbar structure, reduce the manufacturing cost, weaken the harmonic through the short-distance winding and improve the NVH performance of the motor.

Description

Technical Field

[0001] This invention relates to the field of AC motor technology, and in particular to a stator winding structure and winding method for a flat wire motor. Background Technology

[0002] Flat-wire wound motors, due to their advantages such as high slot fill factor, good heat dissipation, and high power density, have been widely used in the field of drive motors for new energy vehicles. Compared with traditional round-wire wound motors, flat-wire wound motors can significantly reduce the DC resistance of the windings, reduce copper losses, and improve the motor's continuous output capability and efficiency. As new energy vehicles continue to demand higher power performance and driving range, higher requirements are being placed on the power density, efficiency, and NVH performance of flat-wire motors.

[0003] For stator windings of flat-wire motors, the winding methods mainly include two types: full-pitch windings and short-pitch windings. Full-pitch windings are simple in structure and easy to manufacture, but their winding coefficients contain high harmonic components, leading to large torque fluctuations during motor operation, which can easily deteriorate the motor's NVH performance and affect the overall vehicle's ride comfort. To improve these problems, existing technologies propose using short-pitch windings to weaken harmonic components, thereby reducing torque ripple and improving the motor's electromagnetic performance. However, existing flat-wire short-pitch winding solutions still have many shortcomings in practical engineering applications.

[0004] First, to achieve end connections in short-pitch windings, various hairpin conductors with different span specifications are typically required at the stator ends. The staggered arrangement of these different span hairpin conductors significantly increases the number of hairpin types. In some flat wire winding schemes, more than ten types of end hairpins are used to achieve specific short-pitch connections. This wide variety of hairpin conductors not only increases mold investment and tooling equipment costs but also enhances the complexity of the insertion process and the difficulty of quality control, hindering large-scale mass production.

[0005] Secondly, in existing flat wire winding schemes, the lead wires of each phase winding are arranged in a relatively dispersed manner. To adapt to the short-pitch winding path under specific pole-slot combinations, the U-phase, V-phase, and W-phase three-phase leads are often distributed at different positions on the stator circumference, resulting in the leads occupying a large circumferential envelope space and affecting the compactness of the motor. At the same time, the dispersed arrangement of the leads also restricts the design space of the subsequent busbars, increasing the complexity of system integration.

[0006] Furthermore, in existing short-pitch winding schemes, due to the dispersed positions of the lead wires of each phase winding and the inconsistent lead wire heights at the ends of each conductor layer, the required busbar structure is typically a multi-layered, three-dimensional bent structure. This type of busbar suffers from problems such as high manufacturing difficulty, high cost, and high resistance loss, further limiting the application of flat wire motors in mass production.

[0007] In addition, at the welding end of the flat wire motor, the ends of each layer of flat wire conductors need to be welded together after being twisted. In the existing solution, the twisting direction of each layer of conductors is relatively uniform, resulting in uneven distribution of weld points at the welding end. This easily leads to weld point stacking and intersection, increasing the difficulty of welding and insulation treatment, and affecting the welding quality and long-term reliability of the motor.

[0008] Therefore, how to further reduce the types of hairpins, simplify the winding process, and optimize the lead wire layout to reduce manufacturing costs and improve the feasibility and reliability of mass production of motors, while achieving short-pitch windings to improve harmonic characteristics, is a technical problem that urgently needs to be solved in the field of flat wire motor winding design. Summary of the Invention

[0009] To address the technical problems existing in the background art, this invention proposes a flat wire motor stator winding structure and its winding method.

[0010] The present invention proposes a flat wire motor stator winding structure, further comprising: flat wire conductor groups stacked radially in each stator slot into four conductor layers, namely layer 1, layer 2, layer 3, and layer 4, with layer 1 located at the innermost radial side of the stator slot and layer 4 located at the outermost radial side of the stator slot; the flat wire conductor groups are connected at the crown end of the stator core via hairpin conductors to form a three-phase winding, the three-phase winding being a U-phase winding, a V-phase winding, and a W-phase winding, the U-phase winding, the V-phase winding, and the W-phase winding being symmetrically distributed 120° electrically in the circumferential direction; the hairpin conductors at the crown end are distributed circumferentially and radially into six hairpin groups, each of the six hairpin groups having different span specifications, wherein the hairpin conductors distributed in layer 1... The span of the hairpin group in the first layer is 9 stator slot pitches. The span of the hairpin group in the second layer is 8 stator slot pitches. The span of the hairpin group in the third layer is 8 stator slot pitches. The hairpin groups in the fourth layer include the first hairpin group with a span of 7 stator slot pitches, the second hairpin group with a span of 8 stator slot pitches, the third hairpin group with a span of 10 stator slot pitches, and the fourth hairpin group with a span of 11 stator slot pitches. On the welding end of the stator core, the ends of each flat wire conductor are welded together after being twisted. The span of the twist is 4.5 stator slot pitches. The leads of the U-phase winding, the leads of the V-phase winding, and the leads of the W-phase winding are concentrated in the same phase area in the circumferential direction at the crown end.

[0011] Preferably, each phase winding occupies a slot area in the circumferential direction, including a first winding slot and a second winding slot. All the flat wire conductors in the first winding slot are used to transmit the AC current of that phase. A portion of the flat wire conductors in the second winding slot are used to transmit the AC current of that phase, and another portion of the flat wire conductors are used to transmit the AC current of another phase. The number of flat wire conductors in the second winding slot that transmit the AC current of that phase is equal to the number of flat wire conductors that transmit the AC current of another phase.

[0012] Preferably, the U-phase winding, V-phase winding, and W-phase winding each contain only one parallel branch.

[0013] Preferably, the 54 stator slots are numbered sequentially from slot 1 to slot 54 along the circumferential direction. The winding path of any one of the U-phase winding, V-phase winding, and W-phase winding is as follows: starting from a preset starting slot and starting layer, the winding alternately passes through the cross-slot connection at the crown end and the cross-layer connection at the welding end, traversing different layers of multiple stator slots along the circumferential direction, and finally forming the lead wire of the phase winding at the welding end. The slot and layer positions of each connection point in the winding path are arranged in a predetermined order to realize the distribution of the phase winding on the circumference.

[0014] Preferably, the winding path of the V-phase winding is offset by 6 stator slot pitches in the circumferential direction in the direction of increasing slot number from the winding path of the U-phase winding.

[0015] Preferably, the winding path of the W-phase winding is offset from the winding path of the U-phase winding by 12 stator slot pitches in the circumferential direction in the direction of increasing slot number.

[0016] Preferably, the leads of the U-phase winding, the leads of the V-phase winding, and the leads of the W-phase winding converge at the crown end and are respectively connected to the three phase input terminals of the same planar busbar, which is located on one side of the axial direction at the crown end.

[0017] Preferably, the hairpin groups distributed in the second layer and the hairpin groups distributed in the third layer have the same structure, and the two are arranged alternately and evenly in the circumferential direction.

[0018] Preferably, at the welding end, the ends of the flat wire conductors of the first layer and the fourth layer are twisted in a first circumferential direction, and the ends of the flat wire conductors of the second layer and the third layer are twisted in a second circumferential direction, with the first direction being opposite to the second direction.

[0019] The present invention proposes a winding method for a flat wire motor stator winding structure, applicable to the flat wire motor stator winding structure described in any of the above claims. The method includes the following steps: S1. Obtain the circumferential position parameters of the 54 stator slots of the stator core and the preset single-phase winding development diagram and three-phase winding development diagram. The single-phase winding development diagram is used to determine the layer distribution of the single-phase winding in each stator slot. The three-phase winding development diagram is used to determine the phase band distribution of the three-phase winding in the circumferential direction. According to the single-phase winding development diagram and the three-phase winding development diagram, insert each flat wire conductor into the corresponding stator slot, so that four conductor layers are formed in each stator slot along the radial direction. S2. Obtain the target value of the twisting span at the welding end. The target value of the twisting span is 4.5 stator slot pitches. Calculate the circumferential twisting angle of the end of each layer of flat wire conductor in each stator slot according to the target value of the twisting span. Perform the twisting operation on the end of each flat wire conductor at the welding end according to the circumferential twisting angle. S3. Obtain the circumferential relative positions of the ends of adjacent flat conductors on the welding end after twisting. Weld the ends of the flat conductors that are circumferentially adjacent after twisting and belong to the same phase winding to form a connection of U-phase winding, V-phase winding and W-phase winding. The connection is a star connection or a delta connection. At the crown end, six hairpin groups are used to connect the flat conductors of each layer. The six hairpin groups have different span specifications. The span of the hairpin group distributed in the first layer is 9 stator slot pitches, and the span of the hairpin group distributed in the second layer is... The span of the group is 8 stator slot pitches. The span of the hairpin group distributed in the 3rd layer is 8 stator slot pitches. The hairpin group distributed in the 4th layer includes the first hairpin group with a span of 7 stator slot pitches, the second hairpin group with a span of 8 stator slot pitches, the third hairpin group with a span of 10 stator slot pitches, and the fourth hairpin group with a span of 11 stator slot pitches. The U-phase lead, V-phase lead, and W-phase lead are concentrated in the same phase area at the crown end and led out to obtain the flat wire motor stator winding structure.

[0020] The proposed flat wire motor stator winding structure and winding method replaces the numerous types of hairpin conductor structures in the prior art by employing six hairpin groups with specific span specifications distributed circumferentially and radially. This reduces the variety of hairpins, lowers mold investment and tooling equipment costs, simplifies the wire insertion process, and improves the feasibility of large-scale mass production. Simultaneously, by concentrating the lead wires of the U-phase, V-phase, and W-phase windings within the same phase region at the crown end, the dispersed arrangement of lead wires in the circumferential direction is avoided, saving circumferential space at the ends, making the motor structure more compact, and facilitating the simplified design of the subsequent busbar. Furthermore, due to the concentrated arrangement of the lead wires, the busbar does not require complex multi-layer three-dimensional bending. The structure can utilize planar busbars for connection, thereby reducing busbar manufacturing costs and connection resistance, and minimizing busbar losses. Furthermore, the welding ends employ a method where the first and fourth layers twist along a first direction, and the second and third layers twist along a second direction in opposite directions, resulting in a uniform distribution of weld points. This avoids weld point stacking and crossing, reducing welding and insulation difficulties, and improving welding quality and long-term motor reliability. Moreover, by setting the twisting span to 4.5 stator slot pitches, combined with the aforementioned hairpin assembly structure, short-pitch windings are achieved to weaken harmonic components, reduce torque pulsation, and improve motor NVH performance, while ensuring the regularity and manufacturability of the winding path. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the three-phase AC power transmission path in one embodiment of the stator winding structure of a flat wire motor proposed in this invention. Figure 2 This is a schematic diagram of the U-phase AC power transmission path in one embodiment of the stator winding structure of a flat wire motor proposed in this invention. Figure 3 This is a single-phase winding development diagram of one embodiment of a flat wire motor stator winding structure proposed in this invention; Figure 4 This is a three-phase winding development diagram of one embodiment of a flat wire motor stator winding structure proposed in this invention; Figure 5 This is a schematic diagram of the first layer of a 9-slot same-layer hairpin in one embodiment of a flat wire motor stator winding structure proposed in this invention; Figure 6 This is a schematic diagram of the second and third layers of the 8-slot hairpin in one embodiment of the flat wire motor stator winding structure proposed in this invention; Figure 7 This is a schematic diagram of the fourth layer of the same-layer hairpin across 7 slots in one embodiment of the flat wire motor stator winding structure proposed in this invention; Figure 8 This is a schematic diagram of the fourth layer of the same-layer hairpin across 8 slots in one embodiment of the flat wire motor stator winding structure proposed in this invention; Figure 9 This is a schematic diagram of the fourth layer of the same-layer hairpin spanning 10 slots, representing one embodiment of the flat wire motor stator winding structure proposed in this invention. Figure 10 This is a schematic diagram of the fourth layer of the same-layer hairpin across 11 slots, representing one embodiment of a flat wire motor stator winding structure proposed in this invention. Figure 11 This is a flowchart illustrating the winding method for a flat wire motor stator winding structure proposed in this invention. Detailed Implementation

[0022] Reference Figures 1-4 The present invention proposes a flat wire motor stator winding structure, including a stator core, 54 stator slots evenly distributed along the circumference of the stator core, and flat wire conductor groups inserted into each stator slot. The structure further includes: the flat wire conductor groups are radially stacked into four conductor layers in each stator slot, namely layer 1, layer 2, layer 3, and layer 4, with layer 1 located at the innermost radial side of the stator slot and layer 4 located at the outermost radial side of the stator slot; the flat wire conductor groups are connected at the crown end of the stator core via hairpin conductors to form a three-phase winding, namely a U-phase winding, a V-phase winding, and a W-phase winding, which are symmetrically distributed 120° electrical angles circumferentially.

[0023] The crown end features six hairpin groups distributed circumferentially and radially, each with a different span specification, such as... Figures 5-10 As shown, the span of the hairpin group distributed in the first layer is 9 stator slot pitches, the span of the hairpin group distributed in the second layer is 8 stator slot pitches, the span of the hairpin group distributed in the third layer is 8 stator slot pitches, and the hairpin group distributed in the fourth layer includes a first hairpin group with a span of 7 stator slot pitches, a second hairpin group with a span of 8 stator slot pitches, a third hairpin group with a span of 10 stator slot pitches, and a fourth hairpin group with a span of 11 stator slot pitches; on the welding end of the stator core, the ends of each flat wire conductor are welded together after being twisted, and the span of the twist is 4.5 stator slot pitches; the leads of the U-phase winding, the leads of the V-phase winding, and the leads of the W-phase winding are concentrated in the same phase area in the circumferential direction at the crown end.

[0024] It should be noted that all the aforementioned hairpin conductors are U-shaped, with their two free ends inserted into two different stator slots. The span between the two free ends is the span specification of the hairpin conductor. The crown end of the hairpin conductor has a rounded bend at the top, located outside the crown end of the stator core. After being inserted into the stator slot, each hairpin conductor has its two free ends extending to the welding end of the stator core.

[0025] In this embodiment, each phase winding occupies a slot area in the circumferential direction, including a first winding slot and a second winding slot. All the flat wire conductors in the first winding slot are used to transmit the AC current of that phase. A portion of the flat wire conductors in the second winding slot are used to transmit the AC current of that phase, and another portion of the flat wire conductors are used to transmit the AC current of another phase. The number of flat wire conductors in the second winding slot that transmit the AC current of that phase is equal to the number of flat wire conductors that transmit the AC current of another phase.

[0026] Specifically, all the flat conductors in the first winding slot are used to transmit the AC current of that phase. That is, the four layers of flat conductors from the first to the fourth layer in the first winding slot belong to the same phase winding, and this slot is not shared with other phase windings. A portion of the flat conductors in the second winding slot are used to transmit the AC current of that phase, and the other portion is used to transmit one of the other two phase AC currents. The number of flat conductors in the second winding slot that transmit the AC current of that phase is equal to the number of flat conductors that transmit the AC current of the other phase. That is, of the four layers of flat conductors in the second winding slot, two layers belong to the current phase winding, and the other two layers belong to the adjacent phase winding. This slot phase distribution rule ensures that the phase windings are symmetrically distributed in the circumferential direction, which helps reduce magnetomotive force harmonics.

[0027] In this embodiment, the U-phase winding, V-phase winding, and W-phase winding each contain only one parallel branch.

[0028] In this embodiment, the winding path of any one of the U-phase winding, V-phase winding, and W-phase winding is as follows: starting from the preset starting slot and starting layer, it alternately passes through the cross-slot connection at the crown end and the cross-layer connection at the welding end, traversing different layers of multiple stator slots in the circumferential direction, and finally forming the lead wire of the phase winding at the welding end; the slot and layer positions of each connection point in the winding path are arranged in a predetermined order to realize the distribution of the phase winding on the circumference.

[0029] Specifically, such as Figures 1-4As shown, the 54 stator slots are numbered sequentially from slot 1 to slot 54 along the circumferential direction. The winding path of any one of the U-phase, V-phase, and W-phase windings is as follows: starting from the 4th layer of slot 31, crossing over to the 4th layer of slot 20 via the crown end, crossing over to the 3rd layer of slot 29 via the welding end, crossing over to the 2nd layer of slot 37 via the crown end, crossing over to the 1st layer of slot 46 via the welding end, crossing over to the 1st layer of slot 37 via the crown end, crossing over to the 2nd layer of slot 28 via the welding end, crossing over to the 3rd layer of slot 20 via the crown end, crossing over to the 4th layer of slot 11 via the welding end, crossing over to the 4th layer of slot 3 via the crown end, crossing over to the 3rd layer of slot 12 via the welding end, crossing over to the 2nd layer of slot 20 via the crown end, crossing over to the 1st layer of slot 29 via the welding ...20 via the crown end, crossing over to the 4th layer of slot 20 via the crown end, crossing over to the 4th layer of slot 29 via the crown end, crossing over to the 4th layer of slot 20 via the crown end, crossing over to the 4th layer of slot 20 via the crown end, crossing over to the 4th layer of slot 20 via the crown end, crossing over to the 4th layer of slot 20 via the crown end, crossing over to the 4th layer The first layer of slot 20, crossing over to the second layer of slot 11 via the welding end, crossing over to the third layer of slot 3 via the crown end, crossing over to the fourth layer of slot 48 via the welding end, crossing over to the fourth layer of slot 38 via the crown end, crossing over to the third layer of slot 47 via the welding end, crossing over to the second layer of slot 1 via the crown end, crossing over to the first layer of slot 10 via the welding end, crossing over to the first layer of slot 1 via the crown end, crossing over to the second layer of slot 46 via the welding end, crossing over to the third layer of slot 38 via the crown end, crossing over to the fourth layer of slot 29 via the welding end, crossing over to the fourth layer of slot 21 via the crown end, crossing over to the third layer of slot 30 via the welding end, crossing over to the second layer of slot 38 via the crown end, crossing over to the first layer of slot 47 via the welding end, crossing over to the first layer of slot 38 via the crown end, crossing over to the first layer of slot 38 via the welding end. Entering the 2nd layer of slot 29, entering the 3rd layer of slot 21 via the crown end, entering the 4th layer of slot 12 via the welding end, entering the 4th layer of slot 4 via the crown end, entering the 3rd layer of slot 13 via the welding end, entering the 2nd layer of slot 21 via the crown end, entering the 1st layer of slot 30 via the welding end, entering the 1st layer of slot 21 via the crown end, entering the 2nd layer of slot 12 via the welding end, entering the 3rd layer of slot 4 via the crown end, entering the 4th layer of slot 49 via the welding end, entering the 4th layer of slot 39 via the crown end, entering the 3rd layer of slot 48 via the welding end, entering the 2nd layer of slot 2 via the crown end, entering the 1st layer of slot 11 via the welding end, entering the 1st layer of slot 2 via the crown end, entering the 2nd layer of slot 47 via the welding end, entering the 2nd layer of slot 47 via the crown end... The end crosses into the 3rd layer of slot 39, then crosses into the 4th layer of slot 30 via the welding end, then crosses into the 4th layer of slot 22 via the crown end, then crosses into the 3rd layer of slot 31 via the welding end, then crosses into the 2nd layer of slot 39 via the crown end, then crosses into the 1st layer of slot 48 via the welding end, then crosses into the 1st layer of slot 39 via the crown end, then crosses into the 2nd layer of slot 30 via the welding end, then crosses into the 3rd layer of slot 22 via the crown end, then crosses into the 4th layer of slot 13 via the welding end, then crosses into the 4th layer of slot 2 via the crown end, then crosses into the 3rd layer of slot 11 via the welding end, then crosses into the 2nd layer of slot 19 via the crown end, then crosses into the 1st layer of slot 28 via the welding end, then crosses into the 1st layer of slot 19 via the crown end, then crosses into the 2nd layer of slot 10 via the welding end, then crosses into the 3rd layer of slot 2 via the crown end.The wire crosses over from the welding end into the 4th layer of slot 47, then through the crown end into the 4th layer of slot 40, then through the welding end into the 3rd layer of slot 49, then through the crown end into the 2nd layer of slot 3, then through the welding end into the 1st layer of slot 12, then through the crown end into the 1st layer of slot 3, then through the welding end into the 2nd layer of slot 48, and finally through the crown end into the 3rd layer of slot 40. The U-phase lead is then drawn out from the welding end.

[0030] In this embodiment, the winding path of the V-phase winding is offset by 6 stator slot pitches in the circumferential direction in the direction of increasing slot number from the winding path of the U-phase winding. That is, the winding path of the V-phase winding is each slot number in the winding path of the U-phase winding plus 6 (if the slot number plus 6 is greater than 54, then 54 is subtracted), and the layer number remains unchanged.

[0031] In this embodiment, the winding path of the W-phase winding is offset by 12 stator slot pitches in the circumferential direction of increasing slot number from the winding path of the U-phase winding. That is, the winding path of the W-phase winding is each slot number in the winding path of the U-phase winding plus 12 (if the slot number plus 12 is greater than 54, then 54 is subtracted), while the layer number remains unchanged.

[0032] The starting point of the U-phase winding is taken as the fourth layer of slot 31. However, those skilled in the art will understand that the stator slot numbering is arbitrarily defined. As long as the relative offset between each phase winding remains unchanged, the winding path of the U-phase winding can be shifted to any starting slot number without departing from the protection scope of this invention. For example, the starting slot of the U-phase winding can be changed from slot 31 to slot 1, and the winding paths of the V-phase and W-phase windings can be shifted accordingly. The technical effect is essentially the same as that of this invention.

[0033] In this embodiment, the hairpin group distributed in the second layer has the same structure as the hairpin group distributed in the third layer, and the two are arranged alternately and evenly in the circumferential direction, so that the connection points of the two middle layers of conductors are evenly distributed in the circumferential direction, which is beneficial to balancing the resistance and inductance of each phase winding.

[0034] In this embodiment, at the welding end, the ends of the flat conductors of the first layer and the fourth layer are twisted in the first circumferential direction, and the ends of the flat conductors of the second layer and the third layer are twisted in the second circumferential direction. The first direction is opposite to the second direction. Through the above-mentioned reverse twisting method, the welding points on the welding end are evenly distributed, avoiding the stacking and crossing of welding points, and reducing the welding difficulty.

[0035] Specifically, the leads of the U-phase winding, V-phase winding, and W-phase winding converge at the crown end and connect to the three phase input terminals of the same planar busbar, which is located on one axial side of the crown end. In other words, the three-phase leads are not dispersed circumferentially but converge within the same circumferential region at the crown end, facilitating connection to external busbars. The planar busbar is a single-layer planar copper busbar structure. Because the three-phase leads are concentrated in the same circumferential region, the planar busbar can complete the electrical connection with the three-phase leads without complex multi-layer three-dimensional bending, reducing the manufacturing cost and connection resistance of the busbar.

[0036] This application reduces the number of hair clip types from 12-15 in the prior art to 6, a reduction of more than 50%. Since each type of hair clip requires a separate molding die, this reduction directly lowers mold investment costs. Simultaneously, the reduction in the number of hair clip types that need to be identified and inserted during the wire insertion process lowers operational complexity, facilitates automated production and quality control, and enhances the feasibility of large-scale mass production.

[0037] Reference Figure 11 The present invention proposes a winding method for a flat wire motor stator winding structure, applicable to any of the flat wire motor stator winding structures described above. The method includes the following steps: S1. Obtain the circumferential position parameters of the 54 stator slots of the stator core and the preset single-phase winding development diagram and three-phase winding development diagram. The single-phase winding development diagram is used to determine the layer distribution of the single-phase winding in each stator slot, and the three-phase winding development diagram is used to determine the phase band distribution of the three-phase winding in the circumferential direction. According to the single-phase winding development diagram and the three-phase winding development diagram, insert each flat wire conductor into the corresponding stator slot, so that four conductor layers are formed in each stator slot along the radial direction.

[0038] In this embodiment, the single-phase winding unfolded diagram defines a first winding slot and a second winding slot. All flat wire conductors inserted in the first winding slot belong to the same phase, and the number of flat wire conductors inserted in the second winding slot is divided into two parts, which belong to two adjacent phases respectively.

[0039] S2. Obtain the target value of the twisting span at the welding end. The target value of the twisting span is 4.5 stator slot pitches. Calculate the circumferential twisting angle of the end of each layer of flat wire conductor in each stator slot according to the target value of the twisting span. Perform the twisting operation on the end of each flat wire conductor at the welding end according to the circumferential twisting angle.

[0040] In this embodiment, the circumferential twisting angle includes a first direction and a second direction. The flat wire conductor ends of the first layer and the fourth layer twist in the first direction, and the flat wire conductor ends of the second layer and the third layer twist in the second direction. The first direction is opposite to the second direction.

[0041] S3. Obtain the circumferential relative positions of the ends of adjacent flat conductors on the welding end after twisting. Weld the ends of the flat conductors that are circumferentially adjacent after twisting and belong to the same phase winding to form the connection of U-phase winding, V-phase winding and W-phase winding. The connection is a star connection or a delta connection. At the crown end, six hairpin groups are used to connect the flat conductors of each layer. The six hairpin groups have different span specifications. The span of the hairpin group distributed in the first layer is 9 stator slot pitches, and the span of the hairpin group distributed in the second layer is... The span is 8 stator slot pitches. The span of the hairpin group distributed in the 3rd layer is 8 stator slot pitches. The hairpin group distributed in the 4th layer includes the first hairpin group with a span of 7 stator slot pitches, the second hairpin group with a span of 8 stator slot pitches, the third hairpin group with a span of 10 stator slot pitches, and the fourth hairpin group with a span of 11 stator slot pitches. The U-phase lead, V-phase lead, and W-phase lead are concentrated in the same phase area at the crown end and led out to obtain the flat wire motor stator winding structure.

[0042] In this embodiment, the U-phase lead, V-phase lead, and W-phase lead are respectively connected to the three phase input terminals of the same planar bus, and the planar bus is fixed to one side of the crown end.

[0043] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A stator winding structure for a flat wire motor, comprising a stator core, 54 stator slots evenly distributed along the circumference of the stator core, and flat wire conductor groups inserted into each stator slot, characterized in that, Also includes: The flat wire conductor group is radially stacked into four conductor layers in each stator slot, namely layer 1, layer 2, layer 3, and layer 4. Layer 1 is located at the innermost radial side of the stator slot, and layer 4 is located at the outermost radial side of the stator slot. The flat wire conductor group is connected at the crown end of the stator core by hairpin conductors to form a three-phase winding. The three-phase windings are U-phase winding, V-phase winding, and W-phase winding. The U-phase winding, V-phase winding, and W-phase winding are symmetrically distributed in the circumferential direction at 120° electrical angles. The hairpin conductors at the crown end are distributed in six hairpin groups along the circumferential and radial directions. The six hairpin groups have different span specifications. Among them, the span of the hairpin group distributed in layer 1 is 9 stator lengths. The stator core has a slot pitch of 8 stator slot pitches in the second layer, 8 stator slot pitches in the third layer, and 7 stator slot pitches, 8 stator slot pitches in the fourth layer, 8 stator slot pitches in the first layer, 8 stator slot pitches in the second layer, 10 stator slot pitches in the third layer, and 11 stator slot pitches in the fourth layer. At the welding end of the stator core, the ends of each flat conductor are twisted and welded together, with the twist spanning 4.5 stator slot pitches. The leads of the U-phase winding, V-phase winding, and W-phase winding are concentrated in the same phase area in the circumferential direction at the crown end.

2. The flat wire motor stator winding structure according to claim 1, characterized in that, Each phase winding occupies a slot area in the circumferential direction, including a first winding slot and a second winding slot. All the flat wire conductors in the first winding slot are used to transmit the AC current of that phase. A portion of the flat wire conductors in the second winding slot are used to transmit the AC current of that phase, and another portion of the flat wire conductors are used to transmit the AC current of another phase. The number of flat wire conductors in the second winding slot that transmit the AC current of that phase is equal to the number of flat wire conductors that transmit the AC current of another phase.

3. The flat wire motor stator winding structure according to claim 1, characterized in that, The U-phase winding, V-phase winding, and W-phase winding each contain only one parallel branch.

4. The flat wire motor stator winding structure according to claim 1, characterized in that, The 54 stator slots are numbered sequentially from slot 1 to slot 54 along the circumference. The winding path of any one of the U-phase winding, V-phase winding, and W-phase winding is as follows: starting from the preset starting slot and starting layer, the winding alternately passes through the cross-slot connection at the crown end and the cross-layer connection at the welding end, traversing different layers of multiple stator slots along the circumference, and finally forming the lead wire of the phase winding at the welding end. The slot and layer positions of each connection point in the winding path are arranged in a predetermined order to realize the distribution of the phase winding on the circumference.

5. The flat wire motor stator winding structure according to claim 4, characterized in that, The winding path of the V-phase winding and the winding path of the U-phase winding are offset by 6 stator slot pitches in the circumferential direction in the direction of increasing slot number.

6. The flat wire motor stator winding structure according to claim 4, characterized in that, The winding path of the W-phase winding is offset by 12 stator slot pitches in the circumferential direction of increasing slot number from the winding path of the U-phase winding.

7. The flat wire motor stator winding structure according to claim 1, characterized in that, The leads of the U-phase winding, the V-phase winding, and the W-phase winding converge at the crown end and are connected to the three phase input terminals of the same planar busbar, which is located on one side of the axial direction at the crown end.

8. The stator winding structure of the flat wire motor according to claim 1, characterized in that, The hairpin groups distributed on the second layer have the same structure as those distributed on the third layer, and they are arranged alternately and evenly in the circumferential direction.

9. The flat wire motor stator winding structure according to claim 1, characterized in that, At the welding end, the ends of the flat conductors of the first layer and the fourth layer are twisted in the first circumferential direction, and the ends of the flat conductors of the second layer and the third layer are twisted in the second circumferential direction, with the first direction being opposite to the second direction.

10. A winding method for a flat wire motor stator winding structure, characterized in that, Applied to the stator winding structure of a flat wire motor as described in any one of claims 1-9, the method includes the following steps: S1. Obtain the circumferential position parameters of the 54 stator slots of the stator core and the preset single-phase winding development diagram and three-phase winding development diagram. The single-phase winding development diagram is used to determine the layer distribution of the single-phase winding in each stator slot. The three-phase winding development diagram is used to determine the phase band distribution of the three-phase winding in the circumferential direction. According to the single-phase winding development diagram and the three-phase winding development diagram, insert each flat wire conductor into the corresponding stator slot, so that four conductor layers are formed in each stator slot along the radial direction. S2. Obtain the target value of the twisting span at the welding end. The target value of the twisting span is 4.5 stator slot pitches. Calculate the circumferential twisting angle of the end of each layer of flat wire conductor in each stator slot according to the target value of the twisting span. Perform the twisting operation on the end of each flat wire conductor at the welding end according to the circumferential twisting angle. S3. Obtain the circumferential relative positions of the ends of adjacent flat conductors on the welding end after twisting. Weld the ends of the flat conductors that are circumferentially adjacent after twisting and belong to the same phase winding to form a connection of U-phase winding, V-phase winding and W-phase winding. The connection is a star connection or a delta connection. At the crown end, six hairpin groups are used to connect the flat conductors of each layer. The six hairpin groups have different span specifications. The span of the hairpin group distributed in the first layer is 9 stator slot pitches, and the span of the hairpin group distributed in the second layer is... The span of the group is 8 stator slot pitches. The span of the hairpin group distributed in the 3rd layer is 8 stator slot pitches. The hairpin group distributed in the 4th layer includes the first hairpin group with a span of 7 stator slot pitches, the second hairpin group with a span of 8 stator slot pitches, the third hairpin group with a span of 10 stator slot pitches, and the fourth hairpin group with a span of 11 stator slot pitches. The U-phase lead, V-phase lead, and W-phase lead are concentrated in the same phase area at the crown end and led out to obtain the flat wire motor stator winding structure.

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