Flat wire motor stator assembly, motor, vehicle

Abstract

The present invention provides a flat wire motor stator assembly, a motor, and a vehicle, wherein the flat wire motor stator assembly includes a stator core, wherein the radial inner side of the yoke ring of the stator core has a plurality of stator teeth arranged at intervals along the circumferential direction thereof, a stator slot is formed between two adjacent stator teeth, a flat wire is wound in the stator slot, and the stator slot includes a plurality of parallel slot segments arranged in sequence from the inside to the outside along the radial direction of the stator core, and the circumferential width of each parallel slot segment gradually increases from the inside to the outside along the radial direction of the stator core. According to the present invention, the problem of excessive AC loss caused by uneven current distribution of the flat wire motor under high-frequency and high-speed working conditions is optimized through the stator slot-type structure with a thin front and a wide back, and at the same time, the width distribution of the front and rear ends of the stator tooth body is more uniform, which alleviates the problem of large local magnetic flux density of the stator tooth body, improves the utilization rate of the core material, reduces the stator iron loss, improves the motor efficiency, and reduces the motor running torque pulsation.

Description

Technical Field

[0001] The invention belongs to the technical field of motor manufacturing, and in particular relates to a flat wire motor stator assembly, a motor, and a vehicle. Background Art

[0002] Electric vehicles are the main type of new energy vehicles. Their core power unit is a permanent magnet synchronous motor. Compared with an electrically excited motor, a permanent magnet synchronous motor rotor uses permanent magnets as the magnetic source, eliminating brushes and other fault-prone structures, and reducing the current loss of the excitation conductor. It has the advantages of small size, high efficiency, high power density and high reliability.

[0003] Most of the motor running losses come from the losses generated by the energized windings. The armature windings are generally made of enameled wires wound in a specific way. Traditional motors generally use round conductors (round wires). Since the outer layer of the conductor insulation has a certain thickness, it will inevitably reduce the net cross-sectional area (copper net slot full rate) of the actual wire (generally copper wire) placed in the slot. Under the same current, the higher the copper net slot full rate, the smaller the winding resistance and the smaller the winding loss. When flat copper wire is embedded, the conductors in the slot are basically in surface contact. Compared with the point contact of round copper wire, the gap between the copper wires during embedding is greatly reduced, and the copper net slot full rate is increased by about 15% to 20%. At the same time, the height of the end winding can be reduced by about 15%, and the surface contact method is more conducive to heat transfer and has better heat dissipation performance. In addition, the flat copper wire conductor has higher stiffness and better motor NVH performance. For new energy vehicles that pursue high torque output, high efficiency and comfort, flat copper wires are naturally endowed with huge potential advantages.

[0004] While reducing DC resistance by increasing the wire diameter and slot fill rate, it also brings some adverse effects. The working principle of a permanent magnet synchronous motor is simply that the stator winding passes three-phase alternating current to generate a rotating magnetic field, which couples with the rotor magnetic field to generate torque to drive the rotor to rotate. However, when the conductor passes alternating current, eddy current effects will be generated, including skin effect and proximity effect. Round copper wires are less affected because of their small wire diameter and dispersed wiring, which offsets most of the effects. Flat copper wires have large wire diameters and are arranged regularly. Under high-frequency (high-speed) conditions, the skin effect is obvious, the current distribution is uneven and concentrated near the stator slot, the conductor resistance increases, and the loss increases. Summary of the invention

[0005] Therefore, the present invention provides a flat wire motor stator assembly, a motor, and a vehicle, which can overcome the shortcomings of the flat wire motor in the prior art, such as the large diameter of the flat wire and the regular arrangement, which lead to obvious skin effect under high-frequency conditions, uneven current distribution and concentration near the stator slot, increased conductor resistance and increased loss.

[0006] In order to solve the above problems, the present invention provides a flat wire motor stator assembly, including a stator core, a yoke ring of the stator core having a plurality of stator teeth arranged at intervals along its circumferential direction on the radial inner side, a stator slot formed between two adjacent stator teeth, a flat wire wound in the stator slot, the stator slot including a plurality of parallel slot segments arranged in sequence from the inside to the outside along the radial direction of the stator core, and a circumferential width of each of the parallel slot segments gradually increasing from the inside to the outside along the radial direction of the stator core.

[0007] In some embodiments, the parallel slot segment includes a first parallel slot segment and a second parallel slot segment, and the first parallel slot segment and the second parallel slot segment are arranged in sequence from the inside to the outside along the radial direction of the stator core. The flat wire includes a first flat wire wound in the first parallel slot segment and a second flat wire wound in the second parallel slot segment. The first flat wire in the first parallel slot segment is provided with n layers, and the circumferential width of each layer of the first flat wire is L1 and the radial length is L2, L1 = (1.2~1.3)*L2, and n is an integer not less than 1.

[0008] In some embodiments, the circumferential width of the first parallel groove segment is L3, and the radial length is L4, L3=L1+(0.8mm-1.0mm), L4=n*(L2+(0.25mm-0.3mm)).

[0009] In some embodiments, the second flat wire in the second parallel slot segment is provided with m layers, and the circumferential width of each layer of the second flat wire is L5 and the radial length is L6, m*L5*L6=Sn*L1*L2, wherein S is the total designed area of ​​the flat wire in a single stator slot, and m is an integer not less than 1.

[0010] In some embodiments, the circumferential width of the second parallel groove segment is L7, and the radial length is L8, L7=L5+(0.8mm-1.0mm), L8=m*(L6+(0.25mm-0.3mm)).

[0011] In some embodiments, n and m are both even numbers.

[0012] In some embodiments, each of the stator teeth includes a tooth segment corresponding to each of the parallel slot segments, a circumferential width of one of the plurality of tooth segments is L9, a circumferential width of another of the plurality of tooth segments is L10, and L9=(0.9-1)L10.

[0013] The present invention also provides a motor, comprising the flat wire motor stator assembly.

[0014] The present invention also provides a vehicle, comprising the above-mentioned motor.

[0015] The present invention provides a flat wire motor stator assembly, motor, and vehicle. The stator slot structure is thin at the front and wide at the rear, which optimizes the problem of excessive AC loss caused by uneven current distribution in high-frequency and high-speed working conditions of the flat wire motor. At the same time, the width distribution of the front and rear ends of the stator teeth is more uniform, which alleviates the problem of large local magnetic density of the stator teeth, improves the utilization rate of the core material, reduces the stator iron loss, improves the motor efficiency, and reduces the torque pulsation of the motor operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the topological structure of a flat wire motor stator assembly according to an embodiment of the present invention (partial, 1 / 8 stator punching sheet);

[0017] Figure 2 A schematic diagram of the topological structure of a flat wire motor stator assembly according to another embodiment of the present invention (partial, 1 / 8 stator punching sheet);

[0018] Figure 3 A schematic diagram of the topological structure of a flat wire motor stator assembly in the prior art (partial, 1 / 8 stator punching sheet);

[0019] Figure 4 The winding AC loss curves of the stator assembly of the present invention and the stator assembly in the prior art at the same rated current and different speeds;

[0020] Figure 5 The winding AC loss curves of the stator assembly of the present invention and the stator assembly in the prior art at the same peak current and different speeds;

[0021] Figure 6 The torque curve of the stator assembly in the prior art at different speeds at rated and peak currents;

[0022] Figure 7 The torque curve of the stator assembly of the present invention at different speeds at rated and peak currents;

[0023] Figure 8 The stator tooth magnetic flux distribution of the stator assembly in the prior art;

[0024] Fig. 9 The stator teeth magnetic flux distribution of the stator assembly of the present invention.

[0025] The reference numerals are:

[0026] 1. stator core; 11. yoke ring; 12. stator teeth; 13. stator slots; 131. first parallel slot segments; 132. second parallel slot segments; 2. flat wires; 21. first flat wires; 22. second flat wires. DETAILED DESCRIPTION

[0027] See also Figures 1 to 9As shown, according to an embodiment of the present invention, a flat wire motor stator assembly is provided, comprising a stator core 1, wherein the radial inner side of a yoke ring 11 of the stator core 1 has a plurality of stator teeth 12 arranged at intervals along the circumferential direction thereof, a stator slot is formed between two adjacent stator teeth 12, a flat wire 2 (specifically, a flat copper wire is used, for example) is wound in the stator slot 13, and the stator slot comprises a plurality of parallel slot segments arranged sequentially from the inside to the outside along the radial direction of the stator core 1, and the circumferential width of each parallel slot segment gradually increases from the inside to the outside along the radial direction of the stator core 1. As described in the background technology, in the prior art, the stator assembly of a flat wire motor is more affected by the eddy current effect as the conductor is closer to the slot opening of the stator slot under high-frequency and high-speed working conditions, resulting in a decrease in the actual utilization rate of the conductor. Therefore, the technical solution of the present invention improves the actual utilization rate of the conductor and reduces the AC loss of the conductor by reducing the area of ​​the flat copper wire near the slot opening. Specifically, in order to make better use of the designable area, the slot width near the slot is reduced. Since the flat wire motor generally adopts a parallel slot design, the tooth width closer to the stator is smaller, and the reduction of the slot width near the slot end can increase the width of the stator tooth at the slot end. Conversely, the part of the conductor material originally reduced near the slot end is supplemented to the stator yoke. The slot width near the yoke increases, while the tooth width decreases. The overall width of the tooth body is more uniform. Compared with the parallel stator slot structure with equal slot width along the stator radial direction in the prior art ( Figure 3 Compared with the above, simulation shows that under the same copper conductor (i.e. flat copper wire) material usage, the armature AC loss is smaller under high-speed conditions (close to 6000rpm or above) (for specific comparison, see Figure 4 and Figure 5 As shown in the figure, and because the width of the stator tooth body near the slot end is relaxed, the problem of excessive saturation of local magnetic flux density on the tooth body is optimized (for specific comparison, see Figure 8 and Fig. 9 As shown), the magnetic potential loss is reduced, and the torque curve (see Figure 6 and Figure 7 As shown in the figure, it can be seen that the optimized stator topology has a larger torque under the same working condition, and because the magnetic flux is more uniform, the torque pulsation is also smaller, especially in the high current working condition (300A), the effect is more obvious (2.8% reduced to 1.8%), which verifies the correctness of the design idea and the superiority of the topology of the present invention (compared with Figure 6 and Figure 7 Corresponding to the current torque and torque pulsation values, it can be seen that Figure 6 (Original structure) has a higher torque at rated current and peak current than the present invention ( Figure 7 ) The torque is low and the torque pulsation is higher than that of the present invention, which reflects the improvement effect of the present invention on the torque performance).

[0028] The parallel slot segments include a first parallel slot segment 131 and a second parallel slot segment 132, the first parallel slot segment 131 and the second parallel slot segment 132 are sequentially arranged from inside to outside along the radial direction of the stator core 1, the flat wire 2 includes a first flat wire 21 wound in the first parallel slot segment 131 and a second flat wire 22 wound in the second parallel slot segment 132, the first flat wire 21 in the first parallel slot segment 131 is provided with n layers, each layer of the first flat wire 21 has a circumferential width of L1 and a radial length of L2, L1=(1.2-1.3)*L2, n is an integer not less than 1, see Figure 1 As shown, at this time n=4, the inventors found that the width-to-narrow ratio has a greater impact on the AC loss and local magnetic density of the flat wire motor. When the width-to-narrow ratio is 1.2-1.3, the AC loss is low and the local magnetic density is more uniform.

[0029] In some embodiments, the circumferential width of the first parallel slot segment 131 is L3, and the radial length is L4, L3=L1+(0.8mm~1.0mm), L4=n*(L2+(0.25mm~0.3mm)), thus, the paint thickness of the flat copper wire, the thickness of the insulating paper used, and the assembly process are fully considered, which is beneficial to the assembly of the corresponding first flat wire 21 in the first parallel slot segment 131, and ensures the smooth contact between the first flat wire 21 and the first parallel slot segment 131.

[0030] In some embodiments, the second flat wire 22 in the second parallel slot segment 132 is provided with m layers, each layer of the second flat wire 22 has a circumferential width of L5 and a radial length of L6, m*L5*L6=Sn*L1*L2, where S is the total designed area of ​​the flat wire in a single stator slot, and m is an integer not less than 1, which can improve the slot fill rate of the stator slot. Figure 1 As shown, m=2. In some embodiments, the circumferential width of the second parallel slot segment 132 is L7, and the radial length is L8, L7=L5+(0.8mm~1.0mm), L8=m*(L6+(0.25mm~0.3mm)), which fully considers the thickness of the flat copper wire paint, the thickness of the insulating paper used, and the assembly process, etc., which is conducive to the assembly of the corresponding first flat wire 21 in the first parallel slot segment 131, and ensures the smooth contact between the first flat wire 21 and the first parallel slot segment 131.

[0031] In some embodiments, n and m are both even numbers, so that the two flat wires at the ends of the stator can be welded together as many times as possible to form two copper wires with equal cross-sectional areas.

[0032] In some embodiments, each of the stator teeth 12 includes a tooth segment corresponding to each of the parallel slot segments, the circumferential width of one of the multiple tooth segments is L9, and the circumferential width of another of the multiple tooth segments is L10, L9=(0.9~1)L10, and the width and height of each slot segment are designed to make the minimum values ​​of the tooth widths of each segment approximately equal, and the width distribution of the front and rear ends is more uniform, which alleviates the problem of locally large magnetic density of the stator tooth body, improves the utilization rate of the core material, and reduces the stator iron loss.

[0033] According to an embodiment of the present invention, there is further provided a motor, comprising the flat wire motor stator assembly described above.

[0034] According to an embodiment of the present invention, a vehicle is also provided, comprising the above-mentioned motor.

[0035] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0036] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A flat wire motor stator assembly, comprising a stator core (1), wherein the radial inner side of a yoke ring (11) of the stator core (1) has a plurality of stator teeth (12) arranged at intervals along the circumferential direction thereof, a stator slot is formed between two adjacent stator teeth (12), and a flat wire (2) is wound in the stator slot (13), wherein: The stator slots comprise a plurality of parallel slot segments arranged in sequence from the inside to the outside along the radial direction of the stator core (1), and the circumferential width of each parallel slot segment gradually increases from the inside to the outside along the radial direction of the stator core (1); the parallel slot segments comprise a first parallel slot segment (131) and a second parallel slot segment (132), and the first parallel slot segment (131) and the second parallel slot segment (132) are arranged in sequence from the inside to the outside along the radial direction of the stator core (1); the flat wire (2) comprises a first flat wire (21) wound in the first parallel slot segment (131) and a second flat wire (21) wound in the second parallel slot segment The second flat wire (22) in the first parallel slot segment (132) is provided with n layers of the first flat wire (21) in the first parallel slot segment (131), and the circumferential width of each layer of the first flat wire (21) is L1, and the radial length is L2, L1 = (1.2-1.3) * L2, n = 4; the second flat wire (22) in the second parallel slot segment (132) is provided with m layers, and the circumferential width of each layer of the second flat wire (22) is L5, and the radial length is L6, m*L5*L6 = Sn*L1*L2, wherein S is the total designed area of ​​the flat wire in a single stator slot, and m = 2.

2. The flat wire motor stator assembly according to claim 1, characterized in that: The circumferential width of the first parallel groove segment (131) is L3, and the radial length is L4, where L3=L1+(0.8mm-1.0mm), and L4=n*(L2+(0.25mm-0.3mm)).

3. The flat wire motor stator assembly according to claim 1, characterized in that: The circumferential width of the second parallel groove segment (132) is L7, and the radial length is L8, L7=L5+(0.8mm-1.0mm), L8=m*(L6+(0.25mm-0.3mm)).

4. The flat wire motor stator assembly according to claim 1, characterized in that: Each of the stator teeth (12) comprises a tooth segment corresponding to each of the parallel slot segments, the circumferential width of one of the plurality of tooth segments is L9, the circumferential width of another of the plurality of tooth segments is L10, and L9=(0.9-1)L10.

5. A motor, characterized in that: A flat wire motor stator assembly comprising any one of claims 1 to 4.

6. A vehicle, characterized in that: Includes the motor described in claim 5.

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