A stator slotting flat wire winding capable of reducing alternating current loss, a stator assembly and a motor

Abstract

This invention relates to a stator slotted flat wire winding, a stator assembly, and a motor that can reduce AC power loss. The flat wire winding includes multiple layers of flat copper wire arranged in the same stator slot, with at least one layer of flat copper wire having through slots on its sidewalls. A stator assembly for reducing AC power loss includes a stator core and the flat wire winding described above. A motor for reducing AC power loss includes a rotor assembly, a motor front end cover, a stator assembly, and a motor housing. The stator assembly is disposed within the motor housing, and the rotor assembly is disposed within the stator assembly. Both ends of the rotor assembly are rotatably connected to the motor housing and the motor front end cover, respectively. The motor front end cover is fixed to the motor housing. The stator assembly is the stator assembly described above. The flat wire winding of this invention, based on the characteristics of AC power loss distribution, rationally slots the flat copper wire conductors to reduce temperature rise within the flat wire slots.

Description

Technical Field

[0001] This invention relates to the field of flat wire motor technology, and more specifically, to a stator slotted flat wire winding, stator assembly, and motor that can reduce AC power loss. Background Technology

[0002] Due to the requirements for overall vehicle weight and space, new energy vehicles place extremely high demands on the power and torque density of their drive motors. Furthermore, the range requirements of new energy passenger vehicles necessitate continuous improvements in the efficiency of drive motors. Compared to traditional round-wire motors, flat-wire motors significantly increase slot fill factor by using flat wires in the stator slots, thereby reducing wire resistance, increasing power and torque, and providing better heat dissipation. Therefore, the application of flat-wire motors in high-performance drive motors for new energy vehicles is an inevitable trend.

[0003] However, the application of flat-wire motors still faces many challenges. For example, permanent magnet synchronous motors have a large number of harmonic magnetic fields in their air gap. When the motor is running, these harmonic magnetic fields act on the copper wires of the stator windings, inducing eddy currents and resulting in eddy current losses. At high speeds, especially in the slot conductors near the air gap, a significant skin effect occurs, leading to increased AC resistance and more pronounced AC losses in the copper wires. Traditional round-wire motors often reduce AC losses by using multiple parallel stranded wires. However, in existing flat-wire motors, there are typically 4, 6, or 8 flat wires in the slots, each with a large cross-sectional area. At high motor speeds, AC losses on the flat copper wires become severe, particularly near the air gap where the temperature of the flat wire layer rises sharply, significantly limiting the motor's power output.

[0004] Existing oil-cooled flat wire motors mainly have two designs: One involves direct oil spraying to cool the end windings, with the cooling oil often in direct contact with the outer surface of the end windings. However, due to the compact arrangement of the end windings in flat wire motors, it is difficult for the cooling oil to penetrate from the outer surface into the interior of the end windings, resulting in uneven temperature distribution inside and outside the windings. The other method involves creating oil slots in the casing and stator core to allow the cooling oil to carry away heat. However, since the main heat-generating part of the motor is the winding within the slots, the above cooling methods are often indirect cooling with limited efficiency. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the first objective of the present invention is to provide a flat wire winding that can reduce AC losses, the second objective of the present invention is to provide a stator assembly that can reduce AC losses and has a good cooling uniformity, and the third objective of the present invention is to provide a motor that can reduce AC losses.

[0006] To achieve the first objective mentioned above, the present invention adopts the following technical solution:

[0007] A flat wire winding that can reduce AC losses includes multiple layers of flat copper wires arranged in the same stator slot, at least one layer of flat copper wires having a through slot on its sidewall, the through slot being located on the side of the flat copper wire close to the rotor assembly and extending axially.

[0008] As a preferred option, the number of through slots on the multilayer flat copper wire decreases sequentially as it moves radially away from the rotor assembly.

[0009] As a preferred embodiment, the thickness of the flat copper wire decreases as the number of through slots decreases.

[0010] To achieve the second objective mentioned above, the present invention adopts the following technical solution:

[0011] A stator assembly that can reduce AC losses includes a stator core and a flat wire winding as described in any of the above. The stator core has a ring of flat wire slots spaced around its circumference, and the flat wire winding is inserted into the flat wire slots. A stator tooth is formed between two adjacent flat wire slots.

[0012] As a preferred embodiment, cooling oil channels are also provided on the two side walls of the flat wire groove away from the rotor assembly.

[0013] As a preferred option, the spacing between the cooling oil passages at corresponding positions of two adjacent flat wire grooves is greater than or equal to the spacing at the opening of the two adjacent flat wire grooves.

[0014] As a preferred embodiment, the width of the cooling oil channel is less than the thickness of the flat copper wire, and the centerline of the cooling oil channel coincides with the centerline of the flat copper wire.

[0015] As a preferred embodiment, the stator core consists of at least two segments, including a first stator core segment and a second stator core segment; the first stator core segment and the second stator core segment are fixedly connected by an oil baffle ring.

[0016] As a preferred embodiment: the oil baffle ring includes an oil baffle ring body and a slot; the oil baffle ring body is provided with a plurality of notches at intervals, the slot is disposed in the notches, and the two ends of the slot protrude from the upper and lower end faces of the oil baffle ring body, and are respectively inserted into the gap between the flat copper wire and the flat wire groove of the first stator core and the second stator core through the two ends of the slot.

[0017] To achieve the third objective mentioned above, the present invention adopts the following technical solution:

[0018] An electric motor capable of reducing AC losses includes a rotor assembly, a front end cover, a stator assembly, and a housing. The stator assembly is disposed within the housing, and the rotor assembly is disposed within the stator assembly. Both ends of the rotor assembly are rotatably connected to the housing and the front end cover, respectively. The front end cover is fixed to the housing. The stator assembly is any of the stator assemblies described above.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] Based on the AC loss distribution characteristics, the flat wire winding of this invention rationally slots the flat copper wire conductor to reduce the temperature rise within the slots. The stator assembly of this invention utilizes slots on both sides of the stator trapezoidal teeth, allowing the cooling oil to directly contact the flat copper wire, thus improving the cooling efficiency of the conductor within the slots. The motor of this invention solves the problem of uneven temperature rise in the end windings by spraying oil from the inside of the windings outwards, first contacting the interior of the end windings. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation thereof.

[0022] Figure 1 This is a schematic diagram of the exploded structure of the motor of the present invention;

[0023] Figure 2 This is a schematic diagram of the stator assembly of the present invention;

[0024] Figure 3 This is a schematic diagram of the stator core cross-sectional structure of the present invention;

[0025] Figure 4 for Figure 3 A partially enlarged structural diagram of part A in the diagram;

[0026] Figure 5 This is a preferred embodiment of the axial cross-section diagram of a single-slot winding in this invention;

[0027] Figure 6 This is a preferred embodiment of the axial cross-section diagram of a single-slot winding in this invention;

[0028] Figure 7 This is a detailed structural schematic diagram of the axial cross-section of a flat copper wire according to the present invention;

[0029] Figure 8 This is a schematic diagram of the oil baffle ring of the present invention;

[0030] Figure 9 for Figure 8 A partially enlarged structural diagram of part B in the diagram;

[0031] Figure 10 This is a schematic diagram of the main oil circuit structure of the present invention.

[0032] The labels in the attached diagram are as follows: 1. Rotor assembly; 2. Motor front end cover; 3. Stator assembly; 4. Motor housing; 3-1. First stator core section; 3-2. Second stator core section; 3-3. Flat wire winding; 3-4. Oil baffle ring; 3-1-1. Stator teeth; 3-1-2. Flat wire slot; 3-1-3. Cooling oil passage; 3-3-1. First layer of flat wire; 3-3-2. Second layer of flat wire; 3-3-3. Third layer of flat wire; 3-3-4. Fourth layer of flat wire; 3-3-5. Fifth layer of flat wire; 3-3-6. Sixth layer of flat wire; 3-3-1-1. Flat copper wire; 3-3-1-2. Flat wire slot; 3-4-1. Oil baffle ring body; 3-4-2. Slot. Detailed Implementation

[0033] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0034] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0035] Furthermore, in the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, unless explicitly defined otherwise.

[0037] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0040] like Figure 1 As shown, a motor that can reduce AC losses includes a rotor assembly 1, a motor front cover 2, a stator assembly 3, and a motor housing 4. The stator assembly 3 is disposed inside the motor housing 4, and the rotor assembly 1 is disposed inside the stator assembly 3. Both ends of the rotor assembly 1 are rotatably connected to the motor housing 4 and the motor front cover 2, respectively. The motor front cover 2 is fixed to the motor housing 4.

[0041] like Figure 2 As shown, the stator assembly 3 includes a stator core and a flat wire winding. A ring of flat wire grooves 3-1-2 is provided on the upper edge of the stator core at intervals along the circumference. The flat wire winding 3-3 is inserted into the flat wire grooves 3-1-2. A stator tooth 3-1-1 is formed between two adjacent flat wire grooves 3-1-2.

[0042] like Figure 3 and Figure 4As shown, cooling oil channels 3-1-3 are also provided on the two side walls of the flat wire groove 3-1-2 away from the rotor assembly 1. Multiple cooling oil channels 3-1-3 are provided and spaced apart. This invention utilizes the characteristic of space wastage due to the unequal radial cross-sectional area of ​​the trapezoidal teeth of the flat wire motor, based on electromagnetic theory. While ensuring unsaturated magnetic flux density in the teeth, toothed oil grooves are provided on both sides of the trapezoidal teeth near the flat wire winding. These toothed oil grooves are composed of the aforementioned multiple spaced cooling oil channels. The cooling oil directly contacts the flat wire winding, carrying heat, thereby improving the motor's heat dissipation efficiency. To facilitate the embedding and fixing of the flat copper wire, it is preferably designed such that the width of the cooling oil channel 3-1-3 is less than the thickness of the flat copper wire 3-3-1-1, and the centerline of the cooling oil channel 3-1-3 coincides with the centerline of the flat copper wire 3-3-1-1. The teeth between adjacent cooling oil channels 3-1-3 are used for positioning and fixing the flat copper wire.

[0043] The spacing between the corresponding cooling oil passages 3-1-3 of two adjacent flat wire grooves 3-1-2 is greater than or equal to the spacing at the openings of the two adjacent flat wire grooves 3-1-2. Utilizing the principle that "there is wasted space in the magnetic flux area at the root of the trapezoidal tooth, and oil cooling water passages are created at the tooth root while ensuring unsaturated magnetic flux density (i.e., the minimum width after slotting at the root is not less than the width at the tooth tip)," as... Figure 4 The two W's are indicated by the logo.

[0044] like Figure 1 and Figure 2 As shown, the stator core consists of at least two segments, including a first stator core segment 3-1 and a second stator core segment 3-2; the first stator core segment 3-1 and the second stator core segment 3-2 are fixedly connected by an oil baffle ring 3-4.

[0045] like Figure 8 and Figure 9 As shown, the oil baffle ring 3-4 includes an oil baffle ring body 3-4-1 and a slot portion 3-4-2. The oil baffle ring body 3-4-1 has multiple notches spaced apart, and the slot portion 3-4-2 is disposed within these notches. Both ends of the slot portion 3-4-2 protrude from the upper and lower end faces of the oil baffle ring body 3-4-1. The slot portion 3-4-2 is inserted into the gap between the flat copper wire 3-3-1-1 and the flat wire groove 3-1-2 of the first stator core 3-1 and the second stator core 3-2, respectively. The oil baffle ring 3-4 is composed of multiple arc segments and is made of carbon fiber.

[0046] This invention divides the stator axially into two sections, with oil entering through the gap between the two iron cores to form an intermediate oil cavity. An oil baffle ring is also provided. The preferred embodiment is that the oil baffle ring consists of four 1 / 4 rings, and the material can be carbon fiber. The first layer of flat wire 3-3-1 is inserted into the gap between the slot portion 3-4-2 near the slot opening of the flat wire slot 3-1-2. This not only serves a fixing function, but also, through the design of a reasonable width, compresses each layer of flat copper wire tightly, so that the flat copper wire is as far away from the slot opening as possible, reducing the AC loss of the flat copper wire and increasing the equivalent heat conduction efficiency in the flat wire slot.

[0047] From a magnetic circuit principle perspective, the extra radial width of the trapezoidal teeth in the stator of existing flat wire motors compared to the parallel teeth of traditional round wire motors is not necessary. Combining this structure, this invention improves the cooling efficiency of the conductor within the slots by creating grooves on both sides of the trapezoidal teeth, allowing cooling oil to directly contact the flat wire; and by spraying oil from the inside of the winding outwards, it addresses the problem of uneven temperature rise in the end windings by first contacting the interior of the end windings. Figure 10 As shown.

[0048] The flat wire winding includes multiple layers of flat copper wires 3-3-1-1 arranged in the same stator slot, with at least one layer of flat copper wires 3-3-1-1 having a through slot 3-3-1-2 on its sidewall. The through slot 3-3-1-2 is located on the side of the flat copper wire 3-3-1-1 closest to the rotor assembly 1 and extends axially. The number of through slots 3-3-1-2 on the multiple layers of flat copper wires 3-3-1-1 decreases sequentially as they move radially away from the rotor assembly 1. The thickness of the flat copper wire 3-3-1-1 decreases as the number of through slots 3-3-1-2 decreases.

[0049] This invention addresses the problem of high AC losses in flat-wire motors caused by the harmonic magnetic field in the air gap. It reduces winding AC losses by slotting the flat wire to interrupt eddy current paths. To minimize the reduction in copper wire cross-sectional area caused by slotting and to reduce processing difficulty, the preferred design is based on the general characteristic that "stator AC losses gradually decrease as the flat copper wire moves radially away from the air gap." The flat wire closest to the air gap has the highest number of slots along the axial direction and facing the air gap surface, with the number of slots decreasing sequentially as the flat wire moves radially away from the air gap. The slotting depth is rationally set according to the AC loss distribution characteristics. Regardless of the method used to slot the flat copper wire, this invention is within the scope of protection of this patent.

[0050] Preferred Option 1: The number and depth of axial slots in the flat copper wire gradually increase from the outer layer to the inner layer. Based on the AC loss characteristics, the number and depth of slots vary in each layer. The specific structure is as follows: Figure 5As shown (taking a six-layer flat wire winding as an example); from the inside out, it includes the first layer flat wire 3-3-1, the second layer flat wire 3-3-2, the third layer flat wire 3-3-3, the fourth layer flat wire 3-3-4, the fifth layer flat wire 3-3-5, and the sixth layer flat wire 3-3-6. All six layers of flat wire have the same thickness. The first layer flat wire 3-3-1 has 5 through slots, and the depth of the through slots decreases from the middle to both sides. The second layer flat wire 3-3-2 has... There are 4 through grooves, and the depth of the through grooves decreases from the middle to both sides. The two through grooves in the middle have the same depth. The third layer flat line 3-3-3 has 3 through grooves, and the depth of the through grooves decreases from the middle to both sides. The fourth layer flat line 3-3-4 has 2 through grooves, and the two through grooves have the same depth. The fifth layer flat line 3-3-5 has 1 through groove. The sixth layer flat line 3-3-6 has no through grooves. The through grooves on the first to fifth layers of flat lines are symmetrically arranged on the left and right sides.

[0051] Preferred Option 2: To reduce processing difficulty, flat wires of the same turn but placed in different layers are given the same number and depth of slots, and axial slots are set for different turns of flat wire from the outer layer to the inner layer according to the AC loss law; to ensure that the cross-sectional area of ​​each coil is equal, the width of each turn of winding is set differently to compensate for the loss of copper wire cross-sectional area caused by slotting. The specific structure is as follows: Figure 6 As shown (taking a six-layer flat wire winding as an example), from the inside out, it includes the first layer of flat wire 3-3-1, the second layer of flat wire 3-3-2, the third layer of flat wire 3-3-3, the fourth layer of flat wire 3-3-4, the fifth layer of flat wire 3-3-5, and the sixth layer of flat wire 3-3-6. The first layer of flat wire 3-3-1 and the second layer of flat wire 3-3-2 each have four through slots of different depths. The third layer of flat wire 3-3-3 and the fourth layer of flat wire 3-3-4 each have three through slots. The grooves have three different depths. The fifth layer flat wire 3-3-5 and the sixth layer flat wire 3-3-6 each have two grooves with different depths. The first layer flat wire 3-3-1 and the second layer flat wire 3-3-2 have the same thickness, which is W1. The third layer flat wire 3-3-3 and the fourth layer flat wire 3-3-4 have the same thickness, which is W2. The fifth layer flat wire 3-3-5 and the sixth layer flat wire 3-3-6 have the same thickness, which is W3. And W1 > W2 > W3.

[0052] The main design concept of this invention is to reduce induced eddy currents by increasing the resistance of the eddy current path and reducing the AC loss induced in the flat wire winding by the air gap harmonic magnetic field through slotting. This solves the problem of the sharp increase in AC loss at high speed in flat wire motors. This invention can effectively reduce the AC loss of flat wire windings, improve motor efficiency, and ultimately improve the output performance of the motor.

[0053] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A flat wire winding that reduces AC losses, comprising multiple layers of flat copper wire (3-3-1-1) arranged in the same stator slot, characterized in that: At least one layer of flat copper wire (3-3-1-1) has a through groove (3-3-1-2) on its side wall. The through slot (3-3-1-2) is provided on the side of the flat copper wire (3-3-1-1) near the rotor assembly (1) and extends axially; The number of through slots (3-3-1-2) on the multilayer flat copper wire (3-3-1-1) decreases sequentially as it moves radially away from the rotor assembly (1); The thickness of the flat copper wire (3-3-1-1) decreases as the number of through slots (3-3-1-2) decreases.

2. A stator assembly capable of reducing AC losses, characterized in that: It includes a stator core and a flat wire winding as described in claim 1. The stator core is provided with a ring of flat wire grooves (3-1-2) spaced around its circumference. The flat wire winding (3-3) is inserted into the flat wire grooves (3-1-2), and a stator tooth (3-1-1) is formed between two adjacent flat wire grooves (3-1-2).

3. A stator assembly for reducing AC losses according to claim 2, characterized in that: Cooling oil passages (3-1-3) are also provided on the two side walls of the flat wire groove (3-1-2) away from the rotor assembly (1).

4. A stator assembly with reduced AC losses according to claim 3, characterized in that: The distance between the cooling oil passages (3-1-3) at the corresponding positions of two adjacent flat wire grooves (3-1-2) is greater than or equal to the distance at the opening of the two adjacent flat wire grooves (3-1-2).

5. A stator assembly with reduced AC losses according to claim 3, characterized in that: The width of the cooling oil channel (3-1-3) is less than the thickness of the flat copper wire (3-3-1-1), and the center line of the cooling oil channel (3-1-3) coincides with the center line of the flat copper wire (3-3-1-1).

6. A stator assembly with reduced AC losses according to claim 2, characterized in that: The stator core is at least two segments, including a first stator core segment (3-1) and a second stator core segment (3-2); the first stator core segment (3-1) and the second stator core segment (3-2) are fixedly connected by an oil baffle ring (3-4).

7. A stator assembly with reduced AC losses according to claim 6, characterized in that: The oil baffle ring (3-4) includes an oil baffle ring body (3-4-1) and a slot (3-4-2); the oil baffle ring body (3-4-1) is provided with multiple notches at intervals, the slot (3-4-2) is disposed in the notches, and the two ends of the slot (3-4-2) protrude from the upper and lower end faces of the oil baffle ring body (3-4-1), and the two ends of the slot (3-4-2) are respectively inserted into the gap between the flat copper wire (3-3-1-1) and the flat wire groove (3-1-2) of the first stator core (3-1) and the second stator core (3-2).

8. A motor capable of reducing AC losses, comprising a rotor assembly (1), a motor front end cover (2), a stator assembly (3), and a motor housing (4), wherein the stator assembly (3) is disposed within the motor housing (4), the rotor assembly (1) is disposed within the stator assembly (3), and both ends of the rotor assembly (1) are rotatably connected to the motor housing (4) and the motor front end cover (2), respectively, and the motor front end cover (2) is fixed to the motor housing (4), characterized in that: The stator assembly (3) is the stator assembly according to any one of claims 2 to 7.

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