Stator assembly and motor

Abstract

The present invention belongs to the technical field of electric motors, and particularly relates to a stator assembly and an electric motor. The stator assembly includes a stator core and a winding; the stator core is provided with a plurality of stator slots, and the stator slots are arranged in sequence along the circumferential direction of the stator core in a ring array; the winding is embedded in the stator slot, and the winding is wound with a rectangular conductor; a plurality of layers of rectangular conductors can be installed in each of the stator slots, and each layer of rectangular conductors is arranged in sequence along the radial direction of the stator core; wherein the cross-sectional area of ​​the rectangular conductor closest to the center of the stator core is greater than the average cross-sectional area of ​​all rectangular conductors in the stator slot. By increasing the area of ​​the conductor in the slot close to the center of the stator core, reducing its loss density, and balancing the heat generation and heat dissipation of different conductors in the stator slot, the purpose of improving the heat dissipation performance of the motor by reducing the maximum temperature of the motor is achieved.

Description

Technical Field

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

[0002] As the new energy vehicle industry develops more maturely, the demand for product cost reduction becomes more urgent. As a key component of the new energy vehicle drive system, the drive motor accounts for a large amount of cost, and motor miniaturization is an important direction for reducing costs. However, one of the main factors restricting the miniaturization of motors is the heating and heat dissipation of motors. If the heating of motors can be effectively reduced or the heat dissipation of motors can be improved, it will help to miniaturize motors and achieve cost reduction effects.

[0003] In terms of reducing the heat generation of the motor, it is common to use low-loss materials to reduce the heat generation, or to use flat wire technology to increase the amount of copper to reduce the heat generation of the motor. The current flat wire technology has not fully utilized its advantage of increasing the amount of copper, which limits the further improvement of motor performance.

[0004] In terms of improving the heat dissipation of the motor, it is common to change the cooling method, such as air cooling, water cooling and oil cooling. At present, no effective improvement measures have been proposed for the uneven distribution of heat in the conductor in the slot, and no effective improvement measures have been proposed for the difference in heat dissipation between the inner and outer layers of the conductor in the slot, which limits the further improvement of the motor performance. Few people consider the effect of balanced heat dissipation of the motor. Summary of the invention

[0005] In view of the above problems, the present invention proposes a stator assembly, which includes a stator core and a winding; the stator core is provided with a plurality of stator slots, and the stator slots are arranged in sequence along the circumferential direction of the stator core in a ring array shape; the winding is embedded in the stator slots, and the winding is wound with a rectangular conductor;

[0006] Several layers of rectangular conductors can be installed in each stator slot, and the layers of rectangular conductors are arranged in sequence along the radial direction of the stator core; wherein the cross-sectional area of ​​the rectangular conductor closest to the center of the stator core is larger than the average cross-sectional area of ​​all rectangular conductors in the stator slot.

[0007] Furthermore, in the same stator slot, the cross-sectional area of ​​a layer of rectangular conductors closest to the center of the stator core is the largest, and the cross-sectional area of ​​a layer of rectangular conductors closest to the outside of the stator core is the smallest.

[0008] Furthermore, in the same stator slot, along the direction from the center of the stator core to the outside of the stator core, the cross-sectional area of ​​the single-layer rectangular conductor in different rectangular slots gradually decreases.

[0009] Furthermore, in the same stator slot, for the cross-sectional area of ​​each layer of rectangular conductors, the cross-sectional area of ​​a layer of rectangular conductors closest to the center of the stator core shall not exceed 1.29 times the average cross-sectional area.

[0010] Furthermore, in the same stator slot, for the cross-sectional area of ​​each layer of rectangular conductors, the minimum cross-sectional area is not less than 0.79 times the average cross-sectional area.

[0011] Furthermore, all the rectangular conductors in the same stator slot can be divided into a plurality of conductor groups along the radial direction of the stator core; each of the conductor groups includes one or more layers of rectangular conductors;

[0012] The stator slots are composed of a plurality of mutually connected rectangular slots; a conductor group is arranged in each rectangular slot, and the size of each rectangular slot is the same as the size of the conductor group in the rectangular slot.

[0013] Furthermore, in the same stator slot, the width of each conductor group increases successively from the center of the stator core to the outside of the stator core.

[0014] Furthermore, in the same stator slot, the height of each conductor group decreases successively from the center of the stator core to the outside of the stator core.

[0015] Furthermore, when the number of conductor groups in the same stator slot is greater than 1, there are at least two conductor groups, wherein the height of the conductor group close to the outside of the core is greater than the height of the conductor group close to the center of the core.

[0016] The present invention also provides a motor, comprising a rotor assembly and the above-mentioned stator assembly, wherein the rotor assembly is located inside the stator assembly.

[0017] The beneficial effect of the embodiment of the present invention is: by increasing the area of ​​the conductor in the slot close to the center of the stator core, reducing its loss density, balancing the heating and heat dissipation of different conductors in the stator slot, so as to achieve the purpose of improving the heat dissipation performance of the motor by reducing the maximum temperature of the motor.

[0018] Other features and advantages of the embodiments of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures indicated in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the existing technical solutions, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic cross-sectional view of a stator slot of Comparative Example 1 of the present invention is shown;

[0021] Figure 2 A schematic diagram showing the temperature field distribution of the conductor in the slot of Comparative Example 1 of the present invention is shown;

[0022] Figure 3 A schematic cross-sectional view of a stator slot according to a first embodiment of the present invention is shown;

[0023] Figure 4 A schematic diagram showing the temperature field distribution of the conductor in the slot according to the first embodiment of the present invention is shown;

[0024] Figure 5 A schematic cross-sectional view of a stator slot according to a second embodiment of the present invention is shown;

[0025] Figure 6 A schematic diagram showing the temperature field distribution of the conductor in the slot according to the second embodiment of the present invention is shown;

[0026] Figure 7 A schematic cross-sectional view of a stator slot according to a third embodiment of the present invention is shown;

[0027] Figure 8 A schematic diagram showing the temperature field distribution of the conductor in the slot according to the third embodiment of the present invention is shown;

[0028] Fig. 9 A schematic cross-sectional view of a stator slot according to a fourth embodiment of the present invention is shown;

[0029] Fig.10 A schematic diagram showing the temperature field distribution of the conductor in the slot according to the fourth embodiment of the present invention is shown;

[0030] Fig.11 A schematic cross-sectional view of a stator slot according to a fifth embodiment of the present invention is shown;

[0031] Fig.12 A schematic diagram of the temperature field distribution of the conductor in the slot of the fifth embodiment of the present invention is shown. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention provides a motor, comprising a rotor assembly and a stator assembly, wherein the rotor assembly is located inside the stator assembly.

[0034] Specifically, the stator assembly includes a stator core and a winding; the stator core is provided with a plurality of stator slots, and the stator slots are arranged in sequence along the circumferential direction of the stator core in a circular array; the winding is embedded in the stator slots, and the winding is wound with a rectangular conductor.

[0035] A plurality of groups of rectangular conductors are arranged in each stator slot, and the layers of rectangular conductors in the same stator slot are arranged in sequence along the radial direction of the stator core; wherein the cross-sectional area of ​​a layer of rectangular conductors closest to the center of the stator core is greater than the average cross-sectional area of ​​all rectangular conductors in the same stator slot.

[0036] The closer the rectangular conductor is to the center of the stator core, the more serious the loss generated, including DC loss and AC loss, and the closer the rectangular conductor is to the center of the stator core, the worse the heat dissipation effect is.

[0037] It should be noted that conductor losses include AC losses and DC losses. AC losses are losses related to the current frequency caused by skin effect, proximity effect, eddy current, etc.; DC losses are the product of the conductor's DC resistance and the square of the current, and have nothing to do with the frequency of the current.

[0038] The embodiment of the present invention increases the cross-sectional area of ​​the rectangular conductor closest to the center of the stator core to reduce its loss density, thereby reducing the maximum temperature of the stator assembly and optimizing the motor performance.

[0039] Furthermore, all rectangular conductors in the same stator slot can be divided into several conductor groups along the radial direction of the stator core. Each conductor group includes one or more layers of rectangular conductors. The cross section of each conductor group is rectangular as a whole, and the size of each conductor group along the radial direction of the stator core is called the height of the conductor group, and the size perpendicular to the radial direction of the stator core is called the width of the conductor group.

[0040] It should be noted that the specific shape of the stator slot is determined by the shape and number of all rectangular conductors in the slot. The stator slot can be considered to be composed of a number of interconnected rectangular slots; a conductor group is arranged in each rectangular slot, and the size of each rectangular slot is the same as the size of the conductor group in it.

[0041] Furthermore, in the same stator slot, the width of each conductor group increases in sequence from the center of the stator core to the outside of the stator core, in a step-like shape. The stator slot is arranged in a step-like shape, that is, the rectangular conductor in the stator slot is in a step-like shape as a whole, which increases the copper usage and reduces the motor loss.

[0042] Preferably, for two adjacent groups of stator slots, the distance between the ends closest to the center of the stator core is equal to or similar to the distance between the ends closest to the outer side of the stator core. The purpose of this setting is to maximize the amount of copper used in the stator assembly as much as possible, ensure that the magnetic circuit of the stator core teeth is unobstructed, and optimize the heat dissipation performance of the motor.

[0043] Preferably, in the same stator slot, the cross-sectional area of ​​a layer of rectangular conductors closest to the center of the stator core is the largest, and the cross-sectional area of ​​a layer of rectangular conductors closest to the outside of the stator core is the smallest.

[0044] The cross-sectional area of ​​the rectangular conductor closest to the center of the stator core is increased to reduce its loss density; the cross-sectional area of ​​the rectangular conductor closest to the outside of the stator core is reduced to increase its loss density. The motor performance is further optimized, and ultimately the heat generation and heat dissipation of the inner and outer rectangular conductors are balanced.

[0045] Further preferably, in the same stator slot, along the direction from the center of the stator core to the outside of the stator core, the cross-sectional area of ​​the single-layer rectangular conductor in different rectangular slots gradually decreases.

[0046] The closer the rectangular conductor is to the center of the stator core, the more serious the loss is, and the worse the heat dissipation effect is; from the inner layer to the outer layer, the loss decreases layer by layer, and the heat dissipation effect also gets better layer by layer. Therefore, from the inner layer to the outer layer, the cross-sectional area of ​​the rectangular conductor in different rectangular slots is gradually reduced, which can achieve the optimal balance between the heating and heat dissipation of the motor.

[0047] Preferably, in the same stator slot, for the cross-sectional area of ​​each layer of rectangular conductors, the cross-sectional area of ​​a layer of rectangular conductors closest to the center of the stator core does not exceed 1.29 times the average cross-sectional area.

[0048] While reducing the loss density of the innermost rectangular conductor, it is also necessary to avoid the innermost rectangular conductor area being too large to affect the forming of the winding.

[0049] Preferably, in the same stator slot, for the cross-sectional area of ​​each layer of rectangular conductors, the minimum cross-sectional area is not less than 0.79 times the average cross-sectional area.

[0050] While reducing the maximum loss density of the winding and ensuring the overall loss density is balanced, avoid the minimum cross-sectional area being too small, which will affect the overall shaping of the winding.

[0051] Comparative Example 1

[0052] like Figure 1As shown, it is an existing technical solution, which adopts stepped slots. Each stator slot is composed of 4 connected rectangular slots, and 8 layers of rectangular conductors are arranged in each stator slot. The rectangular slots of each stator slot are named C1, C2, C3, and C4 in sequence, among which the C1 rectangular slot is located at the slot mouth and is the rectangular slot closest to the center of the core in the slot; the C4 rectangular slot is located at the bottom of the slot and is the rectangular slot closest to the outside of the core in the slot. The rectangular conductors in the same stator slot are named L1, L2, L3, L4, L5, L6, L7, and L8 in sequence, among which the L1 conductor is located at the slot mouth and is the innermost conductor in the slot close to the center of the core; the L8 conductor is located at the bottom of the slot and is the outermost conductor in the slot close to the outside of the core. The height and width of the L1 conductor and the L2 conductor are equal and are accommodated in the C1 rectangular groove, the height and width of the L3 conductor and the L4 conductor are equal and are accommodated in the C2 rectangular groove, the height and width of the L5 conductor and the L6 conductor are equal and are accommodated in the C3 rectangular groove, and the height and width of the L7 conductor and the L8 conductor are equal and are accommodated in the C4 rectangular groove.

[0053] Table 1 Simulation data of conductor in slot in comparative example 1

[0054]

[0055] As shown in Table 1, in Comparative Example 1, the areas of the L1 conductor, L2 conductor, L3 conductor, L4 conductor, L5 conductor, L6 conductor, L7 conductor and L8 conductor in the stator slot are all equal. The cross-sectional area of ​​each layer of rectangular conductors is equal. For the width dimension, the L2 conductor, L4 conductor, L6 conductor, and L8 conductor increase in turn; for the height dimension, the L2 conductor, L4 conductor, L6 conductor, and L8 conductor decrease in turn. For the loss and loss density of a single conductor, the L1 conductor, L2 conductor, L3 conductor, L4 conductor, L5 conductor, L6 conductor, L7 conductor, and L8 conductor all decrease in turn. Among them, the loss density of the innermost rectangular conductor is the largest, which is 0.93W / mm 2 The outermost rectangular conductor has the smallest loss density, which is 0.55W / mm 2 .

[0056] like Figure 2 As shown in Figure 1, it is a simulation schematic diagram of the temperature field distribution of the winding in the slot of the stator assembly when the motor is running in comparative example 1. The specific simulation data can be seen in Table 1. Among them, the temperature gradually decreases from the center of the stator core to the outer wall of the stator core. In the same stator slot, the temperature of the innermost rectangular conductor is the highest, reaching 207.3℃; the temperature of the outermost rectangular conductor is the lowest, reaching 173.1℃; the maximum temperature difference of the winding in the slot is 34.2℃.

[0057] In comparative example 1, the loss density of the innermost rectangular conductor is the largest, and the difference between the maximum loss density and the minimum loss density of the rectangular conductor in the stator slot is large. As a result, the temperature of the innermost rectangular conductor of the winding in the slot is too high, and the temperature difference with the outermost rectangular conductor is large. Therefore, the stator assembly in comparative example 1 has serious losses, and the loss density of the innermost rectangular conductor is large, while the loss density of the outermost rectangular conductor is small, which is not conducive to balanced heat generation and heat dissipation.

[0058] Embodiment 1

[0059] like Figure 3 As shown, in the technical solution provided by this embodiment, the stator slot is also a stepped slot, each stator slot is composed of 4 connected rectangular slots, and 8 layers of rectangular conductors are arranged in each stator slot. The rectangular slots of each stator slot are named C1, C2, C3, and C4 in sequence, where the C1 rectangular slot is located at the slot mouth and is the rectangular slot closest to the center of the core; the C4 rectangular slot is located at the bottom of the slot and is the rectangular slot closest to the outer circle of the core. The rectangular conductors in each stator slot are named L1, L2, L3, L4, L5, L6, L7, and L8 in sequence, where the L1 conductor is located at the slot mouth and is the innermost conductor in the slot close to the center of the core; the L8 conductor is located at the bottom of the slot and is the outermost conductor in the slot close to the outside of the core. The L1 conductor and the L2 conductor belong to the same conductor group, and are both accommodated in the C1 rectangular groove, and the height and width of the two are equal; the L3 conductor and the L4 conductor belong to the same conductor group, and are both accommodated in the C2 rectangular groove, and the height and width of the two are equal; the L5 conductor and the L6 conductor belong to the same conductor group, and are both accommodated in the C3 rectangular groove, and the height and width of the two are equal; the L7 conductor and the L8 conductor belong to the same conductor group, and are both accommodated in the C4 rectangular groove, and the height and width of the two are equal.

[0060] As shown in Table 2, in Embodiment 1, for each rectangular conductor in the stator slot, the width dimension of the L2 conductor, the L4 conductor, the L6 conductor, and the L8 conductor increases in sequence; for the height dimension, the L2 conductor, the L4 conductor, the L6 conductor, and the L8 conductor decrease in sequence; for the conductor cross-sectional area, the L1 conductor and the L2 conductor have the same area, the L3 conductor and the L4 conductor have the same area, the L5 conductor and the L6 conductor have the same area, and the L7 conductor and the L8 conductor have the same area; and the L2 conductor, the L4 conductor, the L6 conductor, and the L8 conductor decrease in sequence, wherein the average cross-sectional area is 8.39 mm 2 , the cross-sectional area of ​​the L1 conductor is 1.29 times the average cross-sectional area, and the cross-sectional area of ​​the L8 conductor is 0.81 times the average cross-sectional area. As for the loss density, the L7 conductor has the largest loss density, which is 0.85W / mm 2 The L2 layer has the lowest loss density, which is 0.48W / mm 2 .

[0061] Table 2 Simulation data of the conductor in the slot in Example 1

[0062]

[0063] like Figure 4 The figure shows a simulation diagram of the temperature field distribution of the winding in the slot of the stator assembly when the motor is running in the first embodiment. The specific simulation data can be seen in Table 2. Among them, the temperature gradually decreases from the center of the stator core to the outer wall of the stator core. In the same stator slot, the temperature of the innermost rectangular conductor is the highest, reaching 183.6°C; the temperature of the outermost rectangular conductor is the lowest, reaching 165.4°C; the maximum temperature difference of the winding in the slot is 18.2°C.

[0064] Compared with comparative example 1, in the stator assembly provided by embodiment 1, the conductor with the largest loss density is the L7 conductor, and the maximum loss density is relatively reduced; and the difference between the maximum loss density and the minimum loss density of the rectangular conductor in the stator slot is reduced, and the loss density of the innermost rectangular conductor is also reduced. As a result, the temperature of the innermost rectangular conductor of the winding in the slot is reduced, that is, the maximum temperature of the winding in the slot is reduced, and the temperature difference with the outermost rectangular conductor is reduced. Therefore, in the stator assembly of embodiment 1, although the loss density of the outer rectangular conductor is increased, the outer rectangular conductor is easy to dissipate heat; the loss density of the innermost rectangular conductor is reduced, which is conducive to balanced heating and heat dissipation.

[0065] Embodiment 2

[0066] like Figure 5 As shown, in the technical solution provided by this embodiment, the stator slot is also a stepped slot, each stator slot is composed of 4 connected rectangular slots, and 8 layers of rectangular conductors are arranged in each stator slot. The rectangular slots of each stator slot are named C1, C2, C3, and C4 in sequence, where the C1 rectangular slot is located at the slot mouth and is the rectangular slot closest to the center of the core; the C4 rectangular slot is located at the bottom of the slot and is the rectangular slot closest to the outer circle of the core. The rectangular conductors in the same stator slot are named L1, L2, L3, L4, L5, L6, L7, and L8 in sequence, where the L1 conductor is located at the slot mouth and is the innermost conductor in the slot close to the center of the core; the L8 conductor is located at the bottom of the slot and is the outermost conductor in the slot close to the outer circle of the core. The L1 conductor and the L2 conductor belong to the same conductor group, and are both accommodated in the C1 rectangular groove, and the height and width of the two are equal; the L3 conductor and the L4 conductor belong to the same conductor group, and are both accommodated in the C2 rectangular groove, and the height and width of the two are equal; the L5 conductor and the L6 conductor belong to the same conductor group, and are both accommodated in the C3 rectangular groove, and the height and width of the two are equal; the L7 conductor and the L8 conductor belong to the same conductor group, and are both accommodated in the C4 rectangular groove, and the height and width of the two are equal.

[0067] As shown in Table 3, in Example 2, for the width dimension, the L2 conductor, L4 conductor, L6 conductor, and L8 conductor increase in sequence. For the height dimension, the L2 conductor, L4 conductor, L6 conductor, and L8 conductor decrease in sequence. For the conductor cross-sectional area, the L1 conductor and the L2 conductor have the same area, the L3 conductor and the L4 conductor have the same area, the L5 conductor and the L6 conductor have the same area, and the L7 conductor and the L8 conductor have the same area; the L2 conductor, the L4 conductor, the L6 conductor, and the L8 conductor decrease in sequence; wherein, the average cross-sectional area is 8.41 mm 2 The cross-sectional area of ​​the L1 conductor is 1.28 times the average cross-sectional area, and the cross-sectional area of ​​the L8 conductor is the smallest, which is 0.80 times the average cross-sectional area. As for the loss density, the L8 conductor has the largest loss density, which is 0.84W / mm 2 The L2 layer has the lowest loss density, which is 0.48W / mm 2 .

[0068] Table 3 Simulation data of the conductor in the slot in Example 2

[0069]

[0070]

[0071] like Figure 6 The figure shows a simulation diagram of the temperature field distribution of the winding in the slot of the stator assembly when the motor is running in Example 2. The specific simulation data can be found in Table 3. Among them, the temperature gradually decreases from the center of the stator core to the outer wall of the stator core. In the same stator slot, the temperature of the innermost rectangular conductor is the highest, reaching 185.1°C; the temperature of the outermost rectangular conductor is the lowest, reaching 164.9°C. The maximum temperature difference of the winding in the slot is 20.2°C.

[0072] Compared with the comparative example 1, in the stator assembly provided by the second embodiment, the outermost rectangular conductor has the largest loss density, the maximum loss density is reduced, and the loss density of the innermost rectangular conductor is reduced. This reduces the temperature of the innermost rectangular conductor of the winding in the slot, that is, the maximum temperature of the winding in the slot is reduced, and the temperature difference with the outermost rectangular conductor is reduced. Therefore, in the stator assembly of the second embodiment, although the loss density of the outer rectangular conductor is increased, the outer rectangular conductor is easy to dissipate heat; the loss density of the innermost rectangular conductor is reduced, which is conducive to balanced heating and heat dissipation.

[0073] Embodiment 3

[0074] like Figure 7As shown, in the technical solution provided by this embodiment, the stator slot is also a stepped slot, each stator slot is composed of 4 connected rectangular slots, and 8 layers of rectangular conductors are arranged in each stator slot. The rectangular slots of each stator slot are named C1, C2, C3, and C4 in sequence, where the C1 rectangular slot is located at the slot mouth and is the rectangular slot closest to the center of the core; the C4 rectangular slot is located at the bottom of the slot and is the rectangular slot closest to the outer circle of the core. The rectangular conductors in the stator slot are named L1, L2, L3, L4, L5, L6, L7, and L8 in sequence, where the L1 conductor is located at the slot mouth and is the innermost conductor in the slot close to the center of the core; the L8 conductor is located at the bottom of the slot and is the outermost conductor in the slot close to the outer circle of the core. The L1 conductor and the L2 conductor belong to the same conductor group, and are both accommodated in the C1 rectangular groove, and the height and width of the two are equal; the L3 conductor and the L4 conductor belong to the same conductor group, and are both accommodated in the C2 rectangular groove, and the height and width of the two are equal; the L5 conductor and the L6 conductor belong to the same conductor group, and are both accommodated in the C3 rectangular groove, and the height and width of the two are equal; the L7 conductor and the L8 conductor belong to the same conductor group, and are both accommodated in the C4 rectangular groove, and the height and width of the two are equal.

[0075] As shown in Table 4, in Example 3, for the width dimension, the L2 conductor, L4 conductor, L6 conductor, and L8 conductor increase in sequence; for the height dimension, the L2 conductor, L4 conductor, L6 conductor, and L8 conductor decrease in sequence. For the conductor cross-sectional area, the L1 conductor and the L2 conductor have the same cross-sectional area, the L3 conductor and the L4 conductor have the same cross-sectional area, the L5 conductor and the L6 conductor have the same cross-sectional area, and the L7 conductor and the L8 conductor have the same cross-sectional area; the L4 conductor, the L2 conductor, the L6 conductor, and the L8 conductor decrease in sequence, wherein the average cross-sectional area is 8.42mm 2 , the cross-sectional area of ​​the L1 conductor is 1.12 times the average cross-sectional area, and the cross-sectional area of ​​the L8 conductor is the smallest, which is 0.79 times the average cross-sectional area. As for the loss density, the L1 conductor has the largest loss density, which is 0.85W / mm 2 The L4 layer has the lowest loss density, which is 0.43W / mm 2 .

[0076] Table 4 Simulation data of the conductor in the slot in Example 3

[0077]

[0078]

[0079] like Figure 8The figure shows a simulation diagram of the temperature field distribution of the winding in the slot of the stator assembly when the motor is running in the third embodiment. The specific simulation data can be seen in Table 4. Among them, the temperature gradually decreases from the center of the stator core to the outer wall of the stator core. In the same stator slot, the temperature of the innermost rectangular conductor is the highest, reaching 184.6°C; the temperature of the outermost rectangular conductor is the lowest, reaching 164.3°C; the maximum temperature difference of the winding in the slot is 20.3°C.

[0080] Compared with the comparative example 1, in the stator assembly provided by the embodiment 3, although the innermost rectangular conductor still has the largest loss density, the maximum loss density is significantly reduced. This reduces the temperature of the innermost rectangular conductor of the winding in the slot, that is, the maximum temperature of the winding in the slot is reduced, and the temperature difference with the minimum temperature of the winding in the slot is reduced. Therefore, in the stator assembly of the embodiment 3, although the loss density of the outer rectangular conductor increases, the outer rectangular conductor is easy to dissipate heat; the loss density of the innermost rectangular conductor is reduced, which is conducive to balanced heating and heat dissipation.

[0081] Embodiment 4

[0082] like Fig. 9 As shown, in the technical solution provided by this embodiment, the stator slot is also a stepped slot, each stator slot is composed of 3 connected rectangular slots, and 8 layers of rectangular conductors are arranged in each stator slot. The rectangular slots of each stator slot are named C1, C2, and C3 in sequence, where the C1 rectangular slot is located at the slot mouth and is the rectangular slot closest to the center of the core; the C3 rectangular slot is located at the bottom of the slot and is the rectangular slot closest to the outer circle of the core. The rectangular conductors in each stator slot are named L1, L2, L3, L4, L5, L6, L7, and L8 in sequence, where the L1 conductor is located at the slot mouth and is the innermost conductor in the slot close to the center of the core; the L8 conductor is located at the bottom of the slot and is the outermost conductor in the slot close to the outer circle of the core. The L1 conductor and the L2 conductor belong to the same conductor group, are both accommodated in the C1 rectangular groove, and have the same height and width; the L3 conductor and the L4 conductor belong to the same conductor group, are both accommodated in the C2 rectangular groove, and have the same height and width; the L5 conductor, the L6 conductor, the L7 conductor and the L8 conductor belong to the same conductor group, are all accommodated in the C3 rectangular groove, and the widths of the four conductors are equal, the heights of the L5 conductor and the L6 conductor are equal, and the heights of the L7 conductor and the L8 conductor are equal.

[0083] Table 5 Simulation data of the conductor in the slot in the fourth embodiment

[0084]

[0085] As shown in Table 5, in Example 4, for the width dimension, the L2 conductor, L4 conductor, and L8 conductor increase in sequence; for the height dimension, the L2 conductor, L4 conductor, L6 conductor, and L8 conductor decrease in sequence. For the conductor cross-sectional area, the L1 conductor and the L2 conductor have the same area, the L3 conductor and the L4 conductor have the same area, the L5 conductor and the L6 conductor have the same area, the L7 conductor and the L8 conductor have the same area, and the L2 conductor, the L4 conductor, the L6 conductor, and the L8 conductor decrease in sequence; wherein, the average cross-sectional area is 8.41 mm 2 , the cross-sectional area of ​​the L1 conductor is 1.28 times the average cross-sectional area, and the cross-sectional area of ​​the L8 conductor is the smallest, which is 0.80 times the average cross-sectional area. For the loss density, the L7 conductor, L8 conductor, L1 conductor, L5 conductor, L6 conductor, L3 conductor, L4 conductor, and L2 conductor decrease in turn. The L7 conductor has the largest loss density, which is 0.81W / mm 2 The L2 layer has the lowest loss density, which is 0.48W / mm 2 .

[0086] like Fig.10 As shown in the figure, it is a simulation schematic diagram of the temperature field distribution of the winding in the slot of the stator assembly when the motor is running in the fourth embodiment. The specific simulation data can be seen in Table 5. Among them, the temperature gradually decreases from the center of the stator core to the outer wall of the stator core. In the same stator slot, the temperature of the innermost rectangular conductor is the highest, reaching 184.3℃; the temperature of the outermost rectangular conductor is the lowest, reaching 165.6℃. The maximum temperature difference of the winding in the slot is 18.7℃.

[0087] Compared with comparative example 1, in the stator assembly provided by embodiment 4, the conductor with the largest loss density is the L7 conductor, and the maximum loss density is reduced; and the difference between the maximum loss density and the minimum loss density of the rectangular conductor in the stator slot is reduced, and the loss density of the innermost rectangular conductor is also reduced. As a result, the temperature of the innermost rectangular conductor of the winding in the slot is reduced, that is, the maximum temperature of the winding in the slot is reduced, and the temperature difference with the outermost rectangular conductor is reduced. Therefore, in the stator assembly in embodiment 4, although the loss density of the outer rectangular conductor is increased, the outer rectangular conductor is easy to dissipate heat; the loss density of the innermost rectangular conductor is reduced, which is conducive to balanced heating and heat dissipation.

[0088] Embodiment 5

[0089] like Fig.11As shown, in the technical solution provided by this embodiment, the stator slot is also a stepped slot, each stator slot is composed of 5 connected rectangular slots, and 8 layers of rectangular conductors are arranged in each stator slot. The rectangular slots of each stator slot are named C1, C2, C3, C4, and C5 in sequence, where the C1 rectangular slot is located at the slot mouth and is the rectangular slot closest to the center of the core; the C5 rectangular slot is located at the bottom of the slot and is the rectangular slot closest to the outer circle of the core. The rectangular conductors in each stator slot are named L1, L2, L3, L4, L5, L6, L7, and L8 in sequence, where the L1 conductor is located at the slot mouth and is the innermost conductor in the slot close to the center of the core; the L8 conductor is located at the bottom of the slot and is the outermost conductor in the slot close to the outer circle of the core. The L1 conductor is contained in the C1 rectangular groove; the L2 conductor and the L3 conductor belong to the same conductor group, are contained in the C2 rectangular groove, and the height and width of the two conductors are equal; the L4 conductor and the L5 conductor belong to the same conductor group, are contained in the C3 rectangular groove, and the height and width of the two conductors are equal; the L6 conductor and the L7 conductor belong to the same conductor group, are contained in the C4 rectangular groove, and the height and width of the two conductors are equal; the L8 conductor is contained in the C5 rectangular groove.

[0090] Table 6 Simulation data of the conductor in the slot in Example 5

[0091]

[0092]

[0093] As shown in Table 6, in Example 5, for the width dimension, the L1 conductor, L3 conductor, L5 conductor, L7 conductor, and L8 conductor increase in sequence. For the height dimension, the L1 conductor, L3 conductor, L5 conductor, L7, and L8 conductor decrease in sequence. For the conductor cross-sectional area, the areas of the L2 conductor and the L3 conductor are equal, the areas of the L4 conductor and the L5 conductor are equal, and the areas of the L6 conductor and the L7 conductor are equal; the L1 conductor, L3 conductor, L5 conductor, L7, and L8 conductor decrease in sequence; wherein, the average cross-sectional area is 8.43 mm 2 , the cross-sectional area of ​​the L1 conductor is 1.28 times the average cross-sectional area, and the cross-sectional area of ​​the L8 conductor is the smallest, which is 0.80 times the average cross-sectional area. As for the loss density, the L8 conductor has the largest loss density, which is 0.83W / mm 2 The L3 layer has the lowest loss density, which is 0.47W / mm 2 .

[0094] like Fig.12As shown in the figure, it is a simulation schematic diagram of the temperature field distribution of the winding in the slot of the stator assembly when the motor is running in Example 5. The specific simulation data can be seen in Table 6. Among them, the temperature gradually decreases from the center of the stator core to the outer wall of the stator core. In the same stator slot, the temperature of the innermost rectangular conductor is the highest, reaching 184.3°C; the temperature of the outermost rectangular conductor is the lowest, reaching 164.2°C. The maximum temperature difference of the winding in the slot is 20.1°C.

[0095] Compared with comparative example 1, in the stator assembly provided by embodiment 5, the outermost rectangular conductor has the largest loss density, and the maximum loss density is reduced; and the difference between the maximum loss density and the minimum loss density of the rectangular conductor in the stator slot is reduced, and the loss density of the innermost rectangular conductor is also reduced. As a result, the temperature of the innermost rectangular conductor of the winding in the slot is reduced, that is, the maximum temperature of the winding in the slot is reduced, and the temperature difference with the outermost rectangular conductor is reduced. Therefore, in the stator assembly in embodiment 5, although the loss density of the outer rectangular conductor is increased, the outer rectangular conductor is easy to dissipate heat; the loss density of the innermost rectangular conductor is reduced, which is conducive to balanced heating and heat dissipation.

[0096] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stator assembly, characterized in that: The stator assembly includes a stator core and a winding; the stator core is provided with a plurality of stator slots, the stator slots are arranged in sequence along the circumferential direction of the stator core in a circular array; the winding is embedded in the stator slots, and the winding is wound with a rectangular conductor; Several layers of rectangular conductors can be installed in each of the stator slots, and the layers of rectangular conductors are arranged in sequence along the radial direction of the stator core; wherein the cross-sectional area of ​​the rectangular conductor closest to the center of the stator core is larger than the average cross-sectional area of ​​all the rectangular conductors in the stator slot; and the cross-sectional area of ​​the layer of rectangular conductors closest to the outside of the stator core is the smallest; All rectangular conductors in the same stator slot can be divided into a plurality of conductor groups along the radial direction of the stator core; each conductor group includes one or more layers of rectangular conductors; The stator slots are composed of a plurality of mutually connected rectangular slots; a conductor group is arranged in each rectangular slot, and the size of each rectangular slot is the same as the size of the conductor group in the rectangular slot; In the same stator slot, the width of each conductor group increases in sequence from the center of the stator core to the outside of the stator core; For two adjacent stator slots, the distance between the ends closest to the center of the stator core is equal to the distance between the ends closest to the outer side of the stator core.

2. A stator assembly according to claim 1, characterized in that: In the same stator slot, the cross-sectional area of ​​a layer of rectangular conductors closest to the center of the stator core is the largest.

3. A stator assembly according to claim 2, characterized in that: In the same stator slot, along the direction from the center of the stator core to the outside of the stator core, the cross-sectional area of ​​the single-layer rectangular conductor in different rectangular slots gradually decreases.

4. A stator assembly according to claim 1 or 3, characterized in that: In the same stator slot, for the cross-sectional area of ​​each layer of rectangular conductors, the cross-sectional area of ​​a layer of rectangular conductors closest to the center of the stator core shall not exceed 1.29 times the average cross-sectional area.

5. A stator assembly according to claim 4, characterized in that: In the same stator slot, for the cross-sectional area of ​​each layer of rectangular conductors, the minimum cross-sectional area is not less than 0.79 times the average cross-sectional area.

6. A stator assembly according to claim 1, characterized in that: In the same stator slot, the height of each conductor group decreases in sequence from the center of the stator core to the outside of the stator core.

7. A stator assembly according to claim 6, characterized in that: When the number of conductor groups in the same stator slot is greater than 1, there are at least two conductor groups, wherein the height of the conductor group close to the outside of the core is greater than the height of the conductor group close to the center of the core.

8. An electric motor, comprising a rotor assembly, characterized in that: It also comprises the stator assembly according to any one of claims 1 to 7, wherein the rotor assembly is located inside the stator assembly.

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