Flat wire short-pitch wave winding structure

Abstract

The application relates to the motor technical field and discloses a flat wire short-pitch wave winding structure, which comprises a three-phase flat wire winding structure embedded in a plurality of stator slots of a permanent magnet motor stator; the three-phase flat wire winding structure comprises U, V and W three-phase winding structures; each stator slot has 2r (r belongs to N*) layers of flat copper conductors; each branch of each phase of the U, V and W three phases comprises r parts; for the flat copper conductor coils of the first part to the rth part, there is 1 slot misplacement between the stator slots where the adjacent flat copper conductor coils are located; the flat wire short-pitch wave winding structure realizes the short-pitch effect.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a flat wire short-pitch wave winding structure. Background Technology

[0002] With the rapid development of new energy vehicle technology, the performance requirements for vehicle drive motors are becoming increasingly higher. The main development trends of new energy vehicle motors are miniaturization and high speed, and miniaturization inevitably requires a significant improvement in motor efficiency.

[0003] Due to the advantages of flat copper wire motors, such as high copper fill factor, good heat dissipation of motor windings, strong voltage resistance of windings, and short winding end length, flat copper wire motors have been widely used in the electric vehicle field in recent years, which can improve the power density and torque density of electric vehicle motors.

[0004] Considering the current processing technology of flat copper wire motors and the influence of motor winding method on torque, most existing motors using flat copper wires are full-pitch windings. However, the winding method of full-pitch windings has a large proportion of odd harmonics, which is one of the reasons for torque pulsation, cogging torque pulsation and harmonic loss. Summary of the Invention

[0005] The present invention provides a flat wire short-pitch wave winding structure, which enables the armature winding to achieve short-pitch distribution and improve the torque pulsation and cogging torque of the motor by weakening odd-order harmonics.

[0006] This invention provides a flat wire short-pitch wave winding structure, comprising:

[0007] The three-phase flat wire winding structure is embedded in multiple stator slots of the permanent magnet motor stator;

[0008] The three-phase flat wire winding structure includes a U, V, and W three-phase winding structure. Each stator slot has 2r layers of flat wire, r∈N*, where N* is a positive integer. Each phase winding structure has two branches connected in parallel. Each branch includes r parts. For the flat wire coils from the first part to the rth part, there is a one-slot misalignment between the stator slots where adjacent flat wire coils are located.

[0009] The aforementioned flat wire coil is composed of multiple unit coils welded together, wherein each unit coil includes:

[0010] The two welding ends, with the lower part sloping outwards, are located at the opening at the tail and are welded to the welding ends of the two adjacent unit coils on the left and right.

[0011] Two effective edges are embedded in the stator slots, which can cut magnetic lines of force to generate induced electromotive force. The two effective edges are integrally connected to two welded ends.

[0012] The U-shaped end is located at the upper closure, and its two ends are integrally connected to the two effective sides one by one.

[0013] The span y1 of the U-shaped end of the nth unit coil, the span x of the two welded ends, and the span y2 of the U-shaped end of the (n+1)th unit coil in the above flat wire winding structure are determined by the following formulas:

[0014] y1+x+y2=kmq, (k=1,2,3...)

[0015] (y1+y2) / 2=y

[0016] Where k is a non-zero integer; m is the number of phases; q is the number of slots per pole per phase; and y is the equivalent pitch, which is the distance between the first part of the phase band and the second part of the phase band of the same phase winding under two adjacent magnetic poles.

[0017] The three spans of each part of the winding are equal, that is, the spans y1 from the first part to the r-th part are all equal, the spans x from the first part to the r-th part are all equal, and the spans y2 from the first part to the r-th part are all equal.

[0018] The manufacturing method of the above-mentioned flat wire winding structure includes the following steps:

[0019] First, it is necessary to perform a twisting operation on the U-shaped end of the individual unit coil and then 3D bending on the whole structure.

[0020] Next, insert the welded end and the effective edge into the corresponding stator slot;

[0021] Finally, the welded ends of two adjacent unit coils are connected by electric welding to form a coil group, and multiple coil groups are connected in parallel to form a flat wire winding structure.

[0022] The above-mentioned flat wire winding structure is a flat copper conductor winding structure.

[0023] The above-mentioned flat wire winding structure is a 60-degree phase band. The total number of flat copper wire windings continuously occupied by the flat wire windings of the same phase under each pole of the 60-degree phase band in the stator slot is: Z*2r / 2p / 3, where Z represents the number of stator slots, Z=mpq, where p is the number of motor poles, m is the number of phases of the flat copper wire windings, q is the number of stator slots per pole per phase, 2r represents the number of winding layers, and P is the number of pole pairs. The phase band is distributed in a sawtooth shape under each pole.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention provides a flat copper conductor motor with a short-pitch stator winding. By weakening odd-order harmonics, the motor's torque ripple and cogging torque are improved, thereby enhancing the motor's torque performance. Furthermore, the winding structure is simple to design, requires less processing technology, and is easy to implement. Attached Figure Description

[0026] Figure 1 This is a diagram of a single component of a flat copper wire winding structure, including two welded ends, a U-shaped end, and two effective sides.

[0027] Figure 2 The present invention provides a structure for an electric motor.

[0028] Figure 3 This is the expanded distribution diagram of the first U-phase winding branch.

[0029] Figure 4 This is the expanded distribution diagram of the second branch of the U-phase winding.

[0030] Figure 5 This is an unfolded diagram of a 6-pole, 36-slot, 6-layer flat copper wire winding structure provided as an example of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-U-shaped end, 2-effective edge, 3-welding end. Detailed Implementation

[0033] The following is in conjunction with the appendix Figure 1-5 The present invention will be described in detail with respect to a specific embodiment, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.

[0034] For ease of understanding, the terms used in this invention will be explained as follows:

[0035] Welding end 3: The part at the tail opening of the flat copper wire winding that connects with the adjacent component is usually connected by electric welding.

[0036] Effective side 2: The part of the flat copper wire winding embedded in the stator slot, which cuts the magnetic lines of force to generate induced electromotive force.

[0037] U-shaped structure end 1: The upper closed part of the flat copper wire winding, connecting the adjacent effective side, located at the end of the motor stator.

[0038] Figure 1 This is a diagram of a single component of a flat copper wire winding structure, including two welded ends, a U-shaped end, and two effective sides.

[0039] Span y1: The distance spanned by the two effective sides of the nth element of the flat copper conductor on the armature surface, that is, the distance spanned by the U-shaped structure end on the armature surface, usually expressed by the number of winding slots opened on the stator core.

[0040] Span x: The distance spanned by the welded end on the armature surface in the flat copper conductor winding structure, that is, the distance between the second effective side of the nth element and the first effective side of the (n+1)th element of the flat copper conductor, usually expressed by the number of winding slots opened on the stator core.

[0041] Span y2: The distance spanned by the two effective sides of the (n+1)th element of the flat copper conductor on the armature surface, i.e., the distance spanned by the U-shaped structure end on the armature surface, usually expressed by the number of winding slots opened on the stator core.

[0042] Pole pitch y0: The range occupied by each magnetic pole along the inner circle of the motor stator core, that is, the span between adjacent N and S poles relative to each other in the slots. Pole pitch can be expressed by the number of slots occupied by each pole: y0 = Z / 2P, where Z is the total number of stator slots on the stator core, and p is the number of pole pairs.

[0043] Equivalent pitch y: For flat copper conductor windings, the equivalent pitch refers to the distance between the first part of the phase band and the second part of the phase band of the same phase winding under adjacent poles.

[0044] Layer number 2r: Each stator slot has 2r layers of effective flat copper conductors.

[0045] This invention provides a flat wire motor stator winding, including a stator and a three-phase flat wire winding structure embedded in the stator slots. This method combines the advantages of flat wire wave winding in terms of processing technology with the characteristics of short-pitch winding in terms of improving motor torque performance.

[0046] The flat copper conductor winding structure includes a three-phase winding structure of U, V, and W, which is embedded in the stator slots of the permanent magnet motor. Due to the special structure of the flat copper conductor, each stator slot is defined as having 2r layers of flat copper conductor (r∈N*). Each branch of each phase consists of r parts. For the coils of the first to the rth parts, the stator slots containing adjacent coils are offset by one slot. That is, the first part of the flat copper conductor is offset by one slot from the second part, the second part is offset by one slot from the third part, ..., and the (r-1)th part is offset by one slot from the rth part. This also means that the equivalent pitch between the phase bands of the windings located under adjacent poles is reduced, achieving a short-pitch effect.

[0047] The flat copper conductor winding structure includes two welded ends, one U-shaped structure end, and two effective sides. The span y1 of the U-shaped structure of the nth element, the span x of the welded end, and the span y2 of the U-shaped structure of the (n+1)th element are determined by the following formulas.

[0048] y1+x+y2=kmq, (k=1,2,3...)

[0049] (y1+y2) / 2=y

[0050] In addition, the span of each part of the winding corresponds one-to-one, which allows each winding coil to be embedded in the stator slot at the same position relative to the stator. This makes the twist degree of the flat copper wire winding structure at the welding end the same, reduces the required precision of the welding process and avoids possible problems in the welding process, and simplifies the processing of the flat copper wire motor winding.

[0051] Currently, the commonly used wire types for motors are round copper wire and flat copper wire. Flat copper wire has a rectangular cross-section, while round copper wire has a circular cross-section. Because round copper wire offers greater flexibility in its placement within the stator slots, short-pitch windings are more widely used in motors using round copper wire. However, flat copper wire has a more complex manufacturing process, requiring specific steps such as… Figure 1 The U-shaped end of a single flat copper wire component is twisted and then bent 3D. Next, its welded end and effective edge are inserted into the corresponding stator slot. Finally, the welded ends of adjacent individual components are connected by electric welding to form a coil group. Multiple coil groups are connected in parallel to form a flat wire winding structure. Therefore, the winding of a flat copper wire motor has high requirements for winding formation, processing difficulty, and installation difficulty. In flat wire motors, the stator winding is mostly a full-pitch winding; short-pitch windings are more difficult to achieve and require higher process requirements. When the motor rotor rotates, the winding in the corresponding stator cuts the rotating magnetic field generated by the rotor, and an induced electromotive force (EMF) is generated in the corresponding stator winding. The direction of this EMF is opposite to the voltage applied across the motor terminals, i.e., it is the back EMF. The coil EMF is the algebraic sum of the back EMF and the voltage across the motor terminals.

[0052] For a full-pitch winding, the effective side span is 180° electrical angle, while for a short-pitch winding, the side span between the two coils is less than 180° electrical angle. Therefore, the back electromotive force of the full-pitch winding is higher, resulting in higher back electromotive force harmonics, which affects the motor performance.

[0053] To address the aforementioned technical problems, this invention provides a flat copper conductor motor with a short-pitch stator winding. By weakening odd-order harmonics, the motor's torque ripple and cogging torque are improved, thereby enhancing the motor's torque performance. Furthermore, the winding structure is simple to design, requires less advanced processing technology, and is easy to implement.

[0054] The motor provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0055] See Figure 2As shown, the number of layers of the flat copper conductor winding structure in each phase within the stator slot is 2r. Each phase winding structure has two parallel branches, each branch consisting of r parts. The first part traverses the first and second winding layers, the second part traverses the third and fourth winding layers, and so on, with the r-th part traversing the (r-1)th and rth winding layers. Furthermore, the stator slots in which each pair of adjacent winding parts are placed are offset by one slot.

[0056] In this embodiment of the invention, the number of stator slots Z of the flat copper wire winding is Z = mpq, where p is the number of motor poles, m is the number of phases of the flat copper wire winding, and q is the number of slots per pole per phase. For example, if the flat copper wire winding is a three-phase winding structure, i.e., m = 3, its number of poles is 3 pairs, the number of poles is 6, i.e., p = 6, and the number of slots per pole per phase is q = 2, then the number of stator slots Z is 36.

[0057] In this embodiment of the invention, the spans y1, y2, and x are determined by the following formulas.

[0058] y1+x+y2=kmq, (k=1,2,3...)

[0059] (y1+y2) / 2=y

[0060] In one possible implementation, Figure 2 The flat copper wire winding motor shown has a 3-phase winding structure, including a U-phase winding structure, a V-phase winding structure, and a W-phase winding structure. The motor has 6 magnetic poles p, 2 slots per pole per phase q, and 6 layers of flat copper wire 2r in each stator slot. Therefore, the number of stator slots Z is 36 slots. That is, the flat copper wire winding motor has a 6-pole, 36-slot, 6-layer stator winding, and the pole pitch y0 is 6.

[0061] The 6-pole, 36-slot, 6-layer flat copper conductor winding structure includes two branch windings, namely branch one and branch two. When the equivalent pitch y is 5, in order to satisfy the constraints of the formula, we take y1 = y2 = 5. When k is 4, the pitch x is 7.

[0062] To improve winding utilization and combined electromotive force, this design selects a 60° phase band. Unlike the traditional uniform distribution of 60° phase bands, in this design, the total number of flat copper conductor windings continuously occupying the same phase winding in the stator slot under each pole of the 60° phase band is Z*2r / 2p / 3, where Z is the number of stator slots, 2r is the number of winding layers, and p is the number of pole pairs. After calculating the spans y1, x, and y2, the phase band is distributed in a sawtooth pattern under each pole.

[0063] Table 1 below shows the phase distribution of branch 1 of the U-phase winding structure in this flat copper conductor winding structure. The shaded area represents the phase band of the U-phase winding structure. The first row of Table 1 shows the stator slot number, and the first column shows the layer number of the flat copper conductor embedded in each stator slot. "+" indicates current flowing into the U1 winding, and "-" indicates current flowing out of the U1 winding.

[0064] Table 1. Distribution of Phase Band in Phase U Winding Branch

[0065]

[0066] Each branch of each phase winding structure has an input terminal and an output terminal, see [link to relevant documentation]. Figure 3 As shown, branch one of the U-phase winding has an input terminal U1+ and an output terminal U1-, that is, as... Figure 3 The branch shown enters from layer a of stator slot 1 and exits from layer f of stator slot 31.

[0067] It should be noted that the U-phase winding branch 1 consists of three parts. The first part traverses layers a and b in the stator slots, the second part traverses layers c and d in the stator slots, and the third part traverses layers e and f in the stator slots. Specifically, the routing of the first part of the U-phase winding branch 1 is as follows: 1a, 6b, 13a, 18b, 25a, 30b; the routing of the second part of the U-phase winding branch 1 is as follows: 2c, 6d, 14c, 19d, 26c, 31d; and the routing of the third part of the U-phase winding branch 1 is as follows: 1e, 6f, 13e, 18f, 25e, 30f.

[0068] Combining Table 1 and Figure 3 The pole pitch y0 can be the span between stator slot 1 and stator slot 7, i.e., y0 = 6. The equivalent pitch of the U-phase winding branch can be the span between stator slot 1 and stator slot 6, or the span between stator slot 2 and stator slot 7, or the span between stator slot 3 and stator slot 8, i.e., its pitch is 5, achieving the effect of short pitch.

[0069] Table 2 below shows the phase band distribution of branch two of the U-phase winding structure in this flat copper conductor winding structure. The shaded area represents the phase band of the U-phase winding structure.

[0070] Table 2 shows the distribution of two-phase bands in the U-phase winding branch.

[0071]

[0072]

[0073] Each branch of each phase winding structure has an input terminal and an output terminal. See [link / reference] Figure 4 As shown, branch two of the U-phase winding has an input terminal U2+ and an output terminal U2-, that is, as Figure 3 Branch line 2 shown in the diagram enters from layer f of stator slot 25 and exits from layer a of stator slot 31.

[0074] It should be noted that the second branch of the U-phase winding also consists of three parts. The first part traverses the f and e layers in the stator slots, the second part traverses the d and c layers in the stator slots, and the third part traverses the b and a layers in the stator slots. Specifically, the routing of the first part of the second branch of the U-phase winding is as follows: 25f, 20e, 13f, 8e, 1f, 32e; the routing of the second part of the second branch of the U-phase winding is as follows: 26d, 21c, 14d, 9c, 2d, 22c; and the routing of the third part of the second branch of the U-phase winding is as follows: 25b, 20a, 13b, 8a, 1b, 32a.

[0075] Combine Table 2 and Figure 4 The pole pitch y0 can be the span between stator slot 1 and stator slot 7, i.e., y0 = 6. The equivalent pitch of the second branch of the U-phase winding can be the span between stator slot 7 and stator slot 12, or the span between stator slot 8 and stator slot 13, or the span between stator slot 9 and stator slot 14, i.e., its pitch is 5, which also achieves the effect of short pitch.

[0076] Table 3 below shows the phase band distribution of this flat copper conductor winding structure.

[0077] Table 3 Phase Zone Distribution of Flat Copper Conductor Winding Structure

[0078]

[0079]

[0080] Combined with Table 3 and Figure 5 The equivalent pitch of the U-phase winding can be the span between stator slots 1 to 6, the equivalent pitch of the V-phase winding can be the span between stator slots 5 and 10, and the equivalent pitch of the W-phase winding can be the span between stator slots 9 and 14. That is, the U, V, and W three-phase flat copper conductor winding structures are symmetrical and have a pitch of 5, achieving the effect of short pitch.

[0081] This invention reduces torque ripple from 25.4% to 1.8%, a reduction of 91.5%, and cogging torque ripple from 3.6 Nm to 0.13 Nm, a reduction of 96.4%.

[0082] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A flat wire short-pitch wave winding structure, characterized in that, include: The three-phase flat wire winding structure is embedded in multiple stator slots of the permanent magnet motor stator; The three-phase flat wire winding structure includes a U, V, and W three-phase winding structure, with 2r layers of flat wire in each stator slot, where r∈N. N It is a positive integer. Each phase winding structure has two branches and the two branches are connected in parallel. Each branch includes r parts. For the flat wire coils from the first part to the rth part, there is a one-slot misalignment between the stator slots where adjacent flat wire coils are located. The flat wire coil is composed of multiple unit coils welded together, and each unit coil includes: The two welding ends (3) are inclined outward at the bottom and located at the opening at the tail, and are welded to the welding ends of the two adjacent unit coils on the left and right. Two effective sides (2) are embedded in the stator slots and can cut magnetic lines of force to generate induced electromotive force. The two effective sides (2) are integrally connected to two welded ends (3). The U-shaped end (1) is located at the upper closed part, and its two ends are integrally connected to the two effective sides (2) in a one-to-one correspondence; The span y1 of the U-shaped end (1) of the nth unit coil of the flat wire winding structure, the span x of the two welded ends (3), and the span y2 of the U-shaped end (1) of the (n+1)th unit coil are determined by the following formulas: y1 + x + y2 = kmq, (k = 1, 2, 3…) (y1+y2) / 2=y Where k is a non-zero integer; m is the number of phases; q is the number of stator slots per pole per phase; and y is the equivalent pitch, which is the distance between the first part of the phase band and the second part of the phase band of the same phase winding under two adjacent magnetic poles. The three spans of each part of the winding are equal, that is, the spans y1 from the first part to the r-th part are all equal, the spans x from the first part to the r-th part are all equal, and the spans y2 from the first part to the r-th part are all equal.

2. The flat wire short-pitch wave winding structure as described in claim 1, characterized in that, The method for manufacturing the flat wire winding structure Includes the following steps: First, it is necessary to perform a torsion operation on the U-shaped end (1) of a single unit coil and then perform a 3D bend on the whole coil. Next, the welding end (3) and the effective edge (2) are inserted into the corresponding stator slots; Finally, the welding ends (3) of two adjacent unit coils are connected by electric welding to form a coil group, and multiple coil groups are connected in parallel to form a flat wire winding structure.

3. The flat wire short-pitch wave winding structure as described in claim 1, characterized in that, The flat wire winding structure is a flat copper conductor winding structure.

4. The flat wire short-pitch wave winding structure as described in claim 3, characterized in that, The flat wire winding structure is a 60-degree phase band. The total number of flat copper wire windings continuously occupied by the flat wire windings of the same phase under each pole of the 60-degree phase band in the stator slot is: Z 2r / 2p / 3, where Z represents the number of stator slots, Z=mpq, where p is the number of motor poles, m is the number of phases of the flat copper wire winding, q is the number of stator slots per pole per phase, 2r represents the number of winding layers, P is the number of pole pairs, and the phase bands are distributed in a sawtooth pattern under each pole.

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