Stator assembly and motor system thereof

Abstract

This invention provides a stator assembly and a motor system having the same. The stator assembly includes: a stator core having multiple axially extending stator slots evenly arranged along the circumference of the stator core; a winding assembly including at least slot-in-slot Litz wires and end flat wires, the slot-in-slot Litz wires passing through the stator slots, and two end flat wires, each end of the slot-in-slot Litz wire connected to one of the end flat wires; and a busbar connected to one of the end flat wires. By applying the technical solution of this invention, due to the inherent structural characteristics of Litz wires, using slot-in-slot Litz wires can effectively reduce the skin effect of the winding assembly, thereby reducing the AC copper loss of the stator assembly, improving the power density and efficiency of the motor. The connection of the two ends of the slot-in-slot Litz wires to the end flat wires results in better end forming of the winding assembly, improving the manufacturing difficulty and height of the winding ends.

Description

Technical Field

[0001] This invention relates to the field of motor design technology, and more specifically, to a stator assembly and a motor system having the same. Background Technology

[0002] Currently, electric vehicle drive motors are primarily flat-wire motors. To continuously improve motor efficiency and power, the number of flat-wire winding layers in these motors has evolved to six, eight, or even ten layers. This results in extremely complex winding and cross-wire configurations, significantly increasing the manufacturing difficulty and cost of the end windings. Furthermore, the uneven current distribution within the conductor causes current to concentrate on the conductor surface, resulting in the skin effect. This is equivalent to a reduced conductor cross-section and increased resistance. As motors evolve towards higher speeds and frequencies, the skin effect becomes increasingly pronounced, leading to increased winding losses and reduced motor efficiency.

[0003] There is currently no effective solution to the technical problem of reduced efficiency of flat wire motors caused by the skin effect of the aforementioned flat wire windings. Summary of the Invention

[0004] The main objective of this invention is to provide a stator assembly and a motor system having the same, so as to solve the problem of reduced efficiency of flat wire motors caused by the skin effect of flat wire windings in the prior art.

[0005] To achieve the above objectives, according to one aspect of the present invention, a stator assembly is provided, comprising: a stator core having a plurality of axially extending stator slots, the plurality of stator slots being uniformly arranged along the circumference of the stator core; a winding assembly comprising at least slot-in-slot Litz wires and end flat wires, the slot-in-slot Litz wires passing through the stator slots, and two end flat wires, the two ends of the slot-in-slot Litz wires being respectively connected to one end flat wire; and a busbar connected to one of the end flat wires.

[0006] Furthermore, two layers of slot-in-slot Litz wire are provided in each stator slot, and the two layers of slot-in-slot Litz wire are arranged with gaps along the radial direction of the stator core.

[0007] Furthermore, the cross-section of the stator slot is trapezoidal, and / or the cross-section of the Litz line within the slot is trapezoidal.

[0008] Furthermore, the Litz wire inside the groove is welded to the end flat wire.

[0009] Furthermore, the length direction of the Litz wire inside the groove is set perpendicular to the length direction of the end flat wire.

[0010] Furthermore, the two end flat lines located at both ends of the Litz line within the same groove are arranged symmetrically about the geometric center of the Litz line within the groove.

[0011] Furthermore, the Litz wire in the groove is made of multiple strands of round wire intertwined, with an insulating varnish film between the strands of round wire, and / or, an insulating varnish film is provided between multiple Litz wires in the groove.

[0012] Furthermore, the winding assembly is a three-phase continuous wave winding.

[0013] Furthermore, the stator core has 72 stator slots, the pole pitch of the winding assembly is 9, at least a portion of the winding assembly has a pitch smaller than the pole pitch, at least a portion of the winding assembly has a pitch equal to the pole pitch, and at least a portion of the winding assembly has a pitch greater than the pole pitch.

[0014] According to another aspect of the present invention, an electric motor system is provided, the electric motor system having a stator assembly and a rotor assembly, the stator assembly being the stator assembly described above.

[0015] By applying the technical solution of this invention, due to the inherent structural characteristics of Litz wire, the use of slot-in Litz wire can effectively reduce the skin effect of the winding assembly, thereby reducing the AC copper loss of the stator assembly and improving the power density and efficiency of the motor. The two ends of the slot-in Litz wire are connected to the end flat wire, which makes the end forming effect of the winding assembly better and improves the process difficulty and height of the winding end. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 A schematic diagram of the structure of a first embodiment of the stator assembly according to the present invention is shown;

[0018] Figure 2 A schematic diagram of a second embodiment of the stator assembly according to the present invention is shown;

[0019] Figure 3 A schematic diagram of a third embodiment of the stator assembly according to the present invention is shown;

[0020] Figure 4 A schematic diagram of a fourth embodiment of the stator assembly according to the present invention is shown;

[0021] Figure 5 It shows Figure 4 An enlarged schematic diagram of part A in the middle;

[0022] Figure 6 A schematic diagram of the winding of a three-phase wire according to an embodiment of the winding assembly of the present invention is shown;

[0023] Figure 7A schematic diagram of the winding of an embodiment of the A-phase wire of the winding assembly according to the present invention is shown.

[0024] The above figures include the following reference numerals:

[0025] 1. Winding assembly; 11. Slotted Litz wire; 12. End flat wire;

[0026] 2. Stator core; 21. Stator slot;

[0027] 3. Busbar. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] 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.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0032] Combination Figures 1 to 7 As shown, according to a specific embodiment of this application, a stator assembly is provided.

[0033] The stator assembly includes a stator core 2, a winding assembly 1, and a busbar 3. The stator core 2 has an axially penetrating stator slot 21, and there are multiple stator slots 21, which are evenly arranged along the circumference of the stator core 2. The winding assembly 1 includes at least a slot-in-slot Litz wire 11 and an end flat wire 12. The slot-in-slot Litz wire 11 passes through the stator slot 21, and there are two end flat wires 12. The two ends of the slot-in-slot Litz wire 11 are respectively connected to one end flat wire 12. The busbar 3 is connected to one of the end flat wires 12.

[0034] By applying the technical solution of this embodiment, due to the structural characteristics of the Litz wire itself, the use of slot-in Litz wire 11 can effectively reduce the skin effect of the winding assembly, thereby reducing the AC copper loss of the stator assembly and improving the power density and efficiency of the motor. The two ends of the slot-in Litz wire 11 are connected to the end flat wire 12, which makes the end forming effect of the winding assembly better and improves the process difficulty and height of the winding end.

[0035] It should be noted that Litz wire, due to its structural characteristics, is relatively soft and cannot be shaped after bending, easily resulting in springback and poor forming effect at the winding ends. Compared with the existing technology that directly uses Litz wire to realize the stator winding, this embodiment sets end flat wires 12 at both ends of the Litz wire 11 in the slot. The end flat wires 12 are copper wires with rectangular cross sections, so that the winding between multiple layers of Litz wires can be realized through the end flat wires 12. The structure of the end flat wires 12 is more conducive to processing and connection than Litz wire, and the forming effect is better, which reduces the difficulty and height of the stator winding process.

[0036] Furthermore, two layers of slot-in-slot Litz wire 11 are provided in each stator slot 21, and the two layers of slot-in-slot Litz wire 11 are provided with gaps along the radial direction of the stator core 2. The provision of two layers of slot-in-slot Litz wire 11 can effectively reduce the difficulty of the insertion process. When the slot-in-slot Litz wire 11 is inserted into the stator slot 21 along the length direction, the process complexity caused by setting multiple layers of slot-in-slot wire can be avoided.

[0037] Specifically, in an exemplary embodiment of this application, the two layers of Litz wires 11 in the slots are arranged with gaps along the radial direction of the stator core 2, so that the two Litz wires 11 in the slots are respectively close to the two opposite slot walls of the stator slot 21.

[0038] Preferably, the stator slot 21 has a trapezoidal cross-section, and / or the Litz wire 11 inside the slot has a trapezoidal cross-section. Setting the cross-section of the stator slot 21 to be trapezoidal increases the copper content inside the stator slot 21 compared to the rectangular cross-section in the prior art. Setting the cross-section of the Litz wire 11 inside the slot to be trapezoidal can improve the slot fill factor and improve the motor efficiency.

[0039] In an exemplary embodiment of this application, the cross-section of the stator slot 21 and the cross-section of the Litz line 11 within the slot are both trapezoidal. The shorter side of the trapezoidal cross-section of the stator slot 21 is positioned close to the geometric center of the stator core 2, while the longer side is positioned close to the edge of the stator core 2. That is, the trapezoidal cross-section of the stator slot 21 is an inverted trapezoid from the outside to the inside in the radial direction. Optionally, the trapezoidal cross-section of the stator slot 21 is an isosceles trapezoid, and the shorter side of the trapezoidal cross-section of the stator slot 21 is positioned at a distance from the inner circular line of the stator core 2. The shorter side of the trapezoidal cross-section of the stator slot 21 is connected to the inner circular line of the stator core 2 through a rectangular channel. The width of the rectangular channel along the circumferential direction of the stator core 2 is smaller than the width of the shorter side of the trapezoidal cross-section of the stator slot 21. The rectangular channel prevents the Litz line 11 within the stator slot 21 from detaching radially.

[0040] Optionally, the trapezoidal cross-section of the Litz wire 11 in the slot is proportionally set to the trapezoidal cross-section of the stator slot 21, or the gap between the two sides of the trapezoidal cross-section of the Litz wire 11 in the slot and the two sides of the trapezoidal cross-section of the corresponding stator slot 21 is set to be the same.

[0041] In conjunction with the aforementioned embodiments, when two layers of slot-in-slot Litz wires 11 are provided in each stator slot 21, and the two layers of slot-in-slot Litz wires 11 are provided with gaps along the radial direction of the stator core 2, and when the cross-section of the stator slot 21 and the cross-section of the slot-in-slot Litz wires 11 are both trapezoidal, the cross-sections of the two slot-in-slot Litz wires 11 are both inverted trapezoidal, and one slot-in-slot Litz wire 11 is close to the long side of the trapezoid of the stator slot 21, and the other slot-in-slot Litz wire 11 is close to the short side of the trapezoid of the stator slot 21.

[0042] Specifically, the Litz wire 11 in the slot is welded to the end flat wire 12. This welding method ensures a stronger connection between the Litz wire 11 in the slot and the end flat wire 12, preventing them from detaching during operation and affecting the normal operation of the stator assembly and motor system. Figure 1 As shown in the figure, point P is the welding point between the Litz wire 11 in the groove and the end flat wire 12.

[0043] Preferably, the two end flat wires 12 located at both ends of the Litz wire 11 in the groove are set to be exactly the same size.

[0044] Furthermore, the length direction of the Litz wire 11 in the groove is perpendicular to the length direction of the end flat wire 12. This arrangement reduces the axial length of the stator assembly and decreases its volume.

[0045] Specifically, in the embodiments of this application, the length direction of the end flat wire 12 is horizontal, and the length direction of the Litz wire 11 in the groove is vertical.

[0046] Furthermore, the two end flat wires 12 located at both ends of the Litz wire 11 within the same groove are symmetrically arranged about the geometric center of the Litz wire 11 within the groove. This arrangement ensures better balance at both ends of the Litz wire 11 within the groove, even force distribution on the Litz wire 11 within the groove, and prevents the Litz wire 11 within the groove from shifting left or right.

[0047] Specifically, such as Figure 6 and Figure 7 As shown in the embodiments of this application, the two end flat wires 12 located at both ends of the Litz wire 11 in the same slot face opposite directions and are connected to the next coil. For example, one end flat wire 12 faces the left side of the Litz wire 11 in the slot, and the other end flat wire 12 faces the right side of the Litz wire 11 in the slot.

[0048] Specifically, the slotted Litz wire 11 is composed of multiple strands of round wire twisted together, with an insulating varnish film between the strands, and / or, an insulating varnish film is provided between multiple slotted Litz wires 11. The slotted Litz wire 11 is composed of multiple strands of round wire twisted together, with the strands twisted and transposed to reduce the skin effect during operation. The insulating varnish film prevents the current from interfering with each other between the multiple strands of round wire and between multiple slotted Litz wires 11, thus avoiding interference with motor operation.

[0049] Furthermore, winding assembly 1 is a three-phase continuous wave winding. The wave winding method makes the winding of winding assembly 1 simpler and avoids the problem of messy wiring arrangement. The wave winding method is more suitable for stator assemblies with a large number of pole pairs.

[0050] like Figure 6 and Figure 7 As shown in the embodiments of this application, the winding assembly 1 is a three-phase continuous wave winding, including phase A, phase B and phase C, with one branch for each phase. Each coil of the winding assembly 1 is welded together by the slotted Litz wire 11 and the end flat wire 12, and each phase winding is wound six turns along the winding direction.

[0051] Specifically, the stator core 2 has 72 stator slots 21, and the pole pitch of the winding assembly 1 is 9. At least a portion of the winding assembly 1 has a pitch smaller than the pole pitch, at least a portion has a pitch equal to the pole pitch, and at least a portion has a pitch greater than the pole pitch. This arrangement allows the winding assembly 1 to simultaneously support short-pitch, long-pitch, and full-pitch cross-wire configurations. The multiple pitch settings of the winding assembly 1 can save copper usage while ensuring motor efficiency.

[0052] In conjunction with the foregoing embodiments, the winding assembly 1 is a three-phase continuous wave winding, and the number of stator slots 21 is 72, having 4 pairs of poles. For example... Figure 6As shown, along the winding direction of the winding assembly 1, the pitches of each group of coils are 7 slots, 8 slots, 9 slots, 10 slots, and 11 slots, respectively, and they are symmetrically distributed. The end flat wires 12 of each group of coils are concentrically arranged. In the winding assembly 1, there are cross-layer wires only between the output ends. The cross-layer wire crossing method is that the second layer crosses over to the first layer after slot 9. The rest are cross-layer wires within the same layer. The cross-layer wire crossing methods are as follows: the first layer crosses over the first layer and the second layer crosses over the second layer when there is a 7-slot gap; the first layer crosses over the first layer and the second layer crosses over the second layer when there is an 8-slot gap; the first layer crosses over the first layer and the second layer crosses over the second layer when there is a 9-slot gap; the first layer crosses over the first layer and the second layer crosses over the second layer when there is a 10-slot gap; and the first layer crosses over the first layer and the second layer crosses over the second layer when there is an 11-slot gap.

[0053] like Figure 7 As shown, taking the A-phase winding connection as an example, the A-phase winding passes through the following slots in sequence: Slot 19, Layer 1; Slot 12, Layer 1; Slot 1, Layer 1; Slot 66, Layer 1; Slot 55, Layer 1; Slot 48, Layer 1; Slot 37, Layer 1; Slot 30, Layer 1; Slot 20, Layer 1; Slot 11, Layer 1; Slot 2, Layer 1; Slot 65, Layer 1; Slot 56, Layer 1; Slot 47, Layer 1; Slot 38, Layer 1; Slot 29, Layer 1; Slot 21, Layer 1; Slot 10, Layer 1; Slot 3, Layer 1; Slot 64, Layer 1; Slot 57, Layer 1; Slot 46, Layer 1; Slot 39, Layer 1; Layer 2, Layer 1; Layer 2, Layer 1; Slot 34, Layer 1; Slot 57, Layer 1; Slot 46, Layer 1; Slot 39, Layer 1; Layer 2 ... Layer 1, Slot 28 (1st layer), Slot 19 (2nd layer), Slot 12 (2nd layer), Slot 1 (2nd layer), Slot 66 (2nd layer), Slot 55 (2nd layer), Slot 48 (2nd layer), Slot 37 (2nd layer), Slot 30 (2nd layer), Slot 20 (2nd layer), Slot 11 (2nd layer), Slot 2 (2nd layer), Slot 65 (2nd layer), Slot 56 (2nd layer), Slot 47 (2nd layer), Slot 38 (2nd layer), Slot 29 (2nd layer), Slot 21 (2nd layer), Slot 10 (2nd layer), Slot 3 (2nd layer), Slot 64 (2nd layer), Slot 57 (2nd layer), Slot 46 (2nd layer), Slot 39 (2nd layer), Slot 28 (2nd layer), outgoing line.

[0054] The stator assembly in the above embodiments has the following beneficial effects:

[0055] 1) By using Litz wire 11 in the stator slot 21, the skin effect of the winding assembly 1 can be effectively reduced, thereby reducing the AC copper loss of the winding and improving the power density and efficiency of the motor.

[0056] 2) The end is connected to the Litz wire 11 in the slot in the form of end flat wire 12, which improves the process difficulty and height of the winding end.

[0057] This embodiment effectively solves the problem of high copper loss caused by the strong skin effect of flat wire windings, while improving the power density and efficiency of motors and improving the end process difficulty of current 6-layer and 8-layer hairpin windings.

[0058] According to another specific embodiment of this application, an electric motor system is provided, the electric motor system having a stator assembly and a rotor assembly, the stator assembly being the stator assembly in the above embodiment.

[0059] According to another specific embodiment of this application, a vehicle is provided, the vehicle having a motor system, the motor system having a stator assembly and a rotor assembly, the stator assembly being the stator assembly in the above embodiment. The vehicle can be of various types, such as electric vehicles, hybrid vehicles, and new energy vehicles.

[0060] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0061] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0062] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A stator assembly, characterized in that, include: Stator core (2), the stator core (2) has an axially penetrating stator slot (21), the stator slot (21) is multiple, and the multiple stator slots (21) are evenly arranged along the circumference of the stator core (2); The winding assembly (1) includes at least an in-slot Litz wire (11) and an end flat wire (12). The in-slot Litz wire (11) passes through the stator slot (21), and there are two end flat wires (12). The two ends of the in-slot Litz wire (11) are respectively connected to one of the end flat wires (12). Busbar (3), the busbar (3) being connected to one of the end flat wires (12); Two layers of slot Litz wire (11) are provided in each stator slot (21), and the two layers of slot Litz wire (11) are provided with a gap along the radial direction of the stator core (2); The cross-section of the stator slot (21) is trapezoidal, and / or the cross-section of the Litz line (11) in the slot is trapezoidal; The stator core (2) has 72 stator slots (21), the pole pitch of the winding assembly (1) is 9, at least a portion of the winding assembly (1) has a pitch smaller than the pole pitch, at least a portion of the winding assembly (1) has a pitch equal to the pole pitch, and at least a portion of the winding assembly (1) has a pitch greater than the pole pitch. Along the winding direction of the winding assembly (1), the pitch of each group of coils is 7 slots, 8 slots, 9 slots, 10 slots and 11 slots respectively, and they are symmetrically distributed. The end flat wires (12) of each group of coils are concentrically arranged. In the winding assembly (1), there are cross-layer wires only between the output ends. The cross-layer wires are crossed from the second layer to the first layer after the 9th slot. The rest are cross-layer wires.

2. The stator assembly according to claim 1, characterized in that, The Litz wire (11) inside the groove is welded to the end flat wire (12).

3. The stator assembly according to claim 1, characterized in that, The length direction of the Litz wire (11) in the groove is perpendicular to the length direction of the end flat wire (12).

4. The stator assembly according to claim 1 or 3, characterized in that, The two end flats (12) located at both ends of the same in-groove Litz line (11) are arranged symmetrically about the geometric center of the in-groove Litz line (11).

5. The stator assembly according to claim 1, characterized in that, The grooved Litz wire (11) is formed by multiple strands of round wires intertwined, with an insulating varnish film between the multiple strands of round wires, and / or, an insulating varnish film between multiple grooved Litz wires (11).

6. The stator assembly according to claim 1, characterized in that, The winding assembly (1) is a three-phase continuous wave winding.

7. An electric motor system having a stator assembly and a rotor assembly, characterized in that, The stator assembly is the stator assembly according to any one of claims 1-6.

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