A motor stator structure compatible with parallel teeth and parallel slots

Abstract

The application relates to a motor stator structure compatible with parallel teeth and parallel slots, comprising a stator core and a flat wire winding, the stator core is provided with stator slots; the flat wire winding comprises a plurality of first flat wires and a plurality of second flat wires, the width of the first flat wires is smaller than that of the second flat wires, cooling flow channels are formed between the plurality of first flat wires and the plurality of second flat wires; when applied to a parallel tooth structure, the cooling flow channels formed between the plurality of first flat wires and the plurality of flat wires are double-cone-shaped, so that the through-flow area of the cooling medium on the slot opening side and the local heat exchange capacity are improved; when applied to a parallel slot structure, the cooling flow channels formed between the plurality of first flat wires and the plurality of flat wires are rectangular, the cross-section thickness or width of the first flat wires is relatively small, the equivalent eddy current loop size in the alternating magnetic field is reduced, and the alternating current additional loss on the slot opening side can be reduced; the second flat wires are arranged on the slot bottom side and are relatively weakly affected by high-frequency magnetic flux leakage, so that a relatively large conductor cross-section area can be adopted to reduce the direct current resistance and direct current copper loss.

Description

Technical Field

[0001] This invention relates to the field of motor stator structure technology, and in particular to a motor stator structure that is compatible with parallel teeth and parallel slots. Background Technology

[0002] With the increasing demands for motor power density and efficiency from new energy vehicles, electric aviation, and high-speed drive systems, rectangular cross-section flat wire windings are widely used due to their advantages such as high slot fill factor, short end length, regular winding arrangement, and clear heat conduction path. Compared with traditional round wire windings, flat wire windings can arrange a higher proportion of copper conductors within a limited sub-slot space, thereby reducing the DC resistance of the windings and improving the motor's torque output capability.

[0003] Under high-speed and high-frequency operating conditions, flat wires near the air gap and slot opening are more susceptible to cogging leakage magnetic field, spatial harmonic magnetic field, end leakage magnetic field, skin effect, and proximity effect. Due to the larger width and thickness of rectangular cross-section flat wires, large equivalent eddy current loops are easily formed inside them, resulting in significantly higher AC additional losses, eddy current losses, and localized heating of slot opening side flat wires compared to slot bottom side flat wires.

[0004] Existing direct cooling solutions in the slot can shorten the heat transfer path through cooling oil circuits between flat wires, between flat wires and slot walls, or between windings and iron cores. However, the flow path shape is often passively determined by the stator slot type and conductor arrangement, and may not match the distribution of the winding heat source.

[0005] like Figure 1 As shown, in the parallel tooth structure, the stator teeth are approximately equal in width radially, which is beneficial for increasing the slot area and the space for copper conductors within the slot. When a cooling channel is set between the left and right windings, the flat wires of the same specification easily make the channel form an inverted trapezoidal or approximately inverted trapezoidal cross-section, which is narrower at the slot opening and wider at the slot bottom. However, this structure results in insufficient flow area, local wetted perimeter, and effective heat transfer boundary in the strong heat source region at the slot opening, while the heat source at the slot bottom is relatively weak but obtains a larger flow area, creating a mismatch between cooling capacity and heat source distribution.

[0006] like Figure 2 As shown, in a parallel slot structure, the cooling channels are more likely to form rectangular or near-rectangular cross-sections, which is beneficial for obtaining a more uniform flow velocity distribution and heat transfer boundary. However, a simple parallel slot structure may lead to an unreasonable distribution of adjacent stator tooth widths, insufficient utilization of tooth area, or excessively high local magnetic flux density, thereby limiting further improvements in high torque density motors.

[0007] Therefore, a new motor stator structure is urgently needed. In the parallel tooth structure, the original inverted trapezoidal cooling channel is optimized into a rectangular or approximately rectangular channel. In the parallel slot structure, the tooth area utilization rate is improved by trapezoidal slots or local trapezoidal slots. Under the same cooling flow rate and similar maximum temperature rise conditions, the thermally limited output torque of the motor is improved. Summary of the Invention

[0008] In view of this, it is necessary to provide a motor stator structure that is compatible with parallel teeth and parallel slots, in order to solve the problems of severe heat generation in the slot opening area of ​​the parallel tooth structure but insufficient coolant flow capacity in the inverted trapezoidal middle channel slot opening side, and the problems of relatively uniform flow channels in the parallel slot structure but insufficient utilization of slot effective area and tooth area.

[0009] On one hand, embodiments of the present invention provide a motor stator structure compatible with parallel teeth and parallel slots, including a stator core and a flat wire winding. The stator core has stator slots. The flat wire winding includes a plurality of first flat wires and a plurality of second flat wires. The plurality of first flat wires and the plurality of second flat wires are symmetrically arranged radially in the stator slots. The first flat wires are disposed near the slot opening of the stator slot, and the second flat wires are disposed away from the slot opening of the stator slot. The width of the first flat wires is smaller than the width of the second flat wires. Double cone or rectangular cooling channels are formed between the plurality of first flat wires and between the plurality of second flat wires.

[0010] Furthermore, the stator core includes a stator yoke and a plurality of stator teeth, one end of the plurality of stator teeth is connected to the stator yoke, and a stator slot is formed between any two adjacent stator teeth.

[0011] Furthermore, the two side walls of the stator teeth are arranged in parallel, and the cooling channel is a double cone.

[0012] Furthermore, the stator slot has a center line extending in the radial direction of the stator core, the distances from the plurality of first flat lines to the center line increase sequentially in the radial direction of the stator core, and the distances from the plurality of second flat lines to the center line increase sequentially in the radial direction of the stator core.

[0013] Furthermore, the two side walls of the stator slot are arranged in parallel, and the cooling channel is rectangular.

[0014] Furthermore, the stator slot has a centerline extending in the radial direction of the stator core, and the distances from the plurality of first flat wires and the plurality of second flat wires to the centerline are all equal.

[0015] Furthermore, it also includes a protective layer disposed within the stator slot.

[0016] Furthermore, the protective layer includes a winding insulation layer that wraps around the exterior of the plurality of first flat wires and the plurality of second flat wires.

[0017] Furthermore, the protective layer includes an in-groove paint layer disposed between two adjacent first flat wires, between two adjacent second flat wires, and between the first flat wire and the second flat wire.

[0018] Furthermore, the protective layer includes a slot wall insulation layer disposed on the inner wall of the stator slot.

[0019] Compared with existing technologies: 1. From a thermal management perspective, the flat line on the slot side is close to the air gap and is a typical strong heat source area. This invention releases the flow channel space through the narrow and thin first flat line on the slot side, so that the cooling flow channel in the middle forms a rectangular or near-rectangular cross-section, thereby improving the flow area of ​​the cooling medium on the slot side and the local heat exchange capacity.

[0020] 2. From the perspective of electromagnetic loss, after the cross-sectional thickness or width of the first flat wire is reduced, the size of its equivalent eddy current loop in the alternating magnetic field is reduced, which can reduce the AC additional loss on the slot side; the second flat wire is arranged on the bottom side of the slot and is relatively less affected by high-frequency leakage magnetic field, so a larger conductor cross-sectional area can be used to reduce DC resistance and DC copper loss.

[0021] 3. From the perspective of structural torque enhancement, traditional flat wire structures of the same specification are often limited by hot spots at the slot opening, making it difficult to further increase the overall current rating. This invention reduces hot spots at the slot opening, increases the cross-sectional area of ​​the conductor on the bottom side of the slot, and improves the heat transfer uniformity of the flow channel, enabling the motor to achieve a higher thermal margin without increasing the cooling flow rate. This thermal margin can be used to increase the allowable phase current, increase the thermally limited continuous torque, or reduce the maximum temperature rise and improve reliability at the same torque. Attached Figure Description

[0022] Figure 1 The existing parallel tooth structure of the motor stator; Figure 2 The existing parallel slot structure of the motor stator; Figure 3 Parallel tooth structure in a motor stator structure compatible with parallel teeth and parallel slots provided in the embodiments of the present invention; Figure 4 The parallel slot structure in the motor stator structure compatible with parallel teeth and parallel slots provided in the embodiments of the present invention; Figure 5 Temperature distribution cloud diagrams of flat wire windings in different simulation comparison groups of parallel tooth structures provided in embodiments of the present invention; Figure 6 Temperature distribution cloud maps of flat wire windings in different simulation comparison groups of the parallel slot structure provided in the embodiments of the present invention.

[0023] Figure label: Stator core 100, stator yoke 110, stator teeth 120, stator slots 101, cooling channels 102; Existing flat wire winding 200 The flat wire winding 300, the first flat wire 310, and the second flat wire 320 of this application; Protective layer 400, winding insulation layer 410, slot varnish layer 420, slot wall insulation layer 430. Detailed Implementation

[0024] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0025] To facilitate understanding of the intent of this invention, it is first necessary to describe and explain the stator structure of a conventional motor. Conventional motor stators include a parallel tooth structure and a parallel slot structure. In the parallel tooth structure, the two side walls of the stator teeth remain parallel radially and have essentially the same width. In the parallel slot structure, the two side walls of the slot formed between two adjacent stator teeth remain parallel radially.

[0026] like Figure 1 As shown, it schematically illustrates the parallel tooth structure of an existing motor stator, including a stator core 100 and multiple existing flat wire windings 200. The stator core 100 includes a stator yoke 110 and multiple stator teeth 120. One end of the multiple stator teeth 120 is connected to the stator yoke 110. The two side walls of each stator tooth 120 are kept parallel in the radial direction. An existing stator slot 101 is formed between two adjacent stator teeth 120. An existing flat wire winding 200 is provided in each stator slot 101.

[0027] The existing flat wire windings 200 have the same cross-sectional structure, consisting of multiple flat wire units arranged radially. These units are sequentially arranged radially on the same side and attached to the inner wall of the corresponding side of the stator teeth 120. In this case, the uniformly sized flat wire units result in cooling channels 102 with a narrower slot opening and a wider slot bottom, forming an inverted trapezoidal or approximately inverted trapezoidal cross-section. This leads to insufficient flow area, localized wetted perimeter, and effective heat transfer boundary in the strong heat source region on the slot opening side, while the relatively weaker heat source on the slot bottom side achieves a larger flow area, creating a mismatch between cooling capacity and heat source distribution.

[0028] like Figure 2 As shown, it schematically illustrates the parallel slot structure of an existing motor stator, including a stator core 100 and multiple existing flat wire windings 200. The stator core 100 includes a stator yoke 110 and multiple stator teeth 120. One end of the multiple stator teeth 120 is connected to the stator yoke 110. An existing stator slot 101 is formed between two adjacent stator teeth 120. The two side walls of the stator slot 101 are kept parallel in the radial direction. An existing flat wire winding 200 is provided in each stator slot 101.

[0029] The existing flat wire winding 200 has the same cross-sectional structure, consisting of multiple flat wire units arranged radially. These units are sequentially arranged radially on the same side and attached to the inner wall of the corresponding side of the stator tooth 120. In this configuration, the cooling channel 102 can easily form a rectangular or approximately rectangular cross-section, which is beneficial for obtaining a more uniform flow velocity distribution and heat transfer boundary. However, simply parallel slots may lead to unreasonable tooth width distribution between adjacent stator teeth 120, insufficient tooth area utilization, or excessively high local magnetic flux density, thus limiting further improvements in high torque density motors.

[0030] like Figure 3 and Figure 4 As shown, an embodiment of the present invention provides a motor stator structure compatible with parallel teeth and parallel slots, including a stator core 100 and a flat wire winding 300. The stator core 100 has stator slots 101; the flat wire winding 300 includes a plurality of first flat wires 310 and a plurality of second flat wires 320. The plurality of first flat wires 310 and the plurality of second flat wires 320 are symmetrically arranged radially in the stator slots 101. The first flat wires 310 are located close to the slot opening of the stator slot 101, and the second flat wires are located away from the slot opening of the stator slot 101. The width of the first flat wires 310 is smaller than the width of the second flat wires 320. Double cone or rectangular cooling channels 102 are formed between the plurality of first flat wires 310 and between the plurality of second flat wires 320.

[0031] The stator core 100 in this embodiment has stator slots 101.

[0032] In one embodiment, the stator core 100 includes a stator yoke 110 and a plurality of stator teeth 120, one end of the plurality of stator teeth 120 being connected to the stator yoke 110, and stator slots 101 being formed between any adjacent stator teeth 120.

[0033] It is understood that the stator yoke 110 in the stator core 100 can be either annular or arc-shaped. When the stator yoke 110 adopts an annular structure, it is connected to multiple stator teeth 120, which are evenly arranged around the circumference of the stator yoke 110. When the stator yoke 110 adopts an arc-shaped structure, multiple stator yokes 110 are connected sequentially to form an annular structure, and each stator yoke 110 is connected to two stator teeth 120.

[0034] Figure 3 and Figure 4 The stator yoke 110 shown is an arc-shaped strip. Of course, in other preferred embodiments, the stator yoke 110 may also adopt a ring structure, which is not limited.

[0035] The flat wire winding 300 in this embodiment includes a plurality of first flat wires 310 and a plurality of second flat wires 320. The plurality of first flat wires 310 and the plurality of second flat wires 320 are symmetrically arranged in the stator slots 101 along the radial direction of the stator core 100. The first flat wires 310 are located close to the slot opening of the stator slot 101, and the second flat wires are located away from the slot opening of the stator slot 101. The width of the first flat wires 310 is smaller than the width of the second flat wires 320. A double-cone or rectangular cooling channel 102 is formed between the plurality of first flat wires 310 and between the plurality of second flat wires 320.

[0036] In this embodiment, the first flat wire 310 is located near the slot opening of the stator slot 101 or near the air gap side. The first flat wire 310 preferably adopts a rectangular cross-section conductor with a smaller width, smaller thickness or smaller cross-sectional area to reduce the equivalent eddy current loop size of the slot opening area under the action of tooth leakage magnetic flux, spatial harmonic leakage magnetic flux, skin effect and proximity effect, and to release the space of the cooling channel 102 on the slot opening side.

[0037] In this embodiment, the second flat wire 320 is disposed near the bottom side of the stator slot 101 or away from the air gap side. The second flat wire 320 is preferably a rectangular cross-section conductor with a larger width, a larger thickness or a larger cross-sectional area, so as to reduce the DC resistance of the winding away from the air gap side and improve the current carrying capacity of the bottom side region of the slot.

[0038] It should be noted that the width, thickness and cross-sectional area ratio of the first flat wire 310 and the second flat wire 320 can be adjusted according to different motor slot types, speeds, frequencies, cooling medium properties and winding connection methods.

[0039] It is understood that the first flat wire 310 and the second flat wire 320 can be connected in conventional series, parallel or other winding connection methods suitable for flat wire motors. This invention does not require that the two types of flat wires be controlled independently.

[0040] When applied to a parallel tooth structure, the two side walls of the stator teeth 120 are arranged in parallel, and the cooling channel 102 is a double cone. In this embodiment, the stator slot 101 has a centerline extending in the radial direction of the stator core 100, the distances of the plurality of first flat lines 310 to the centerline increase sequentially in the radial direction of the stator core 100, and the distances of the plurality of second flat lines 320 to the centerline increase sequentially in the radial direction of the stator core 100.

[0041] When applied to a parallel slot structure, the two side walls of the stator slot 101 are arranged in parallel, and the cooling channel 102 is rectangular. In this embodiment, the stator slot 101 has a centerline extending in the radial direction of the stator core 100, and the distances from the centerline to the plurality of first flat lines 310 and the plurality of second flat lines 320 are all equal.

[0042] The cooling channel 102 is rectangular or biconical (approximately rectangular). Of course, the cooling channel 102 can also be a partially stepped rectangular channel, a combined rectangular channel, or a rectangular channel with chamfers, rounded corners, or small transition sections.

[0043] In this embodiment, the cooling channel 102 is used to supply cooling oil, insulating coolant, water-glycol coolant, or other cooling media suitable for direct cooling within the motor slot.

[0044] This embodiment also includes a protective layer 400 disposed in the stator slot 101.

[0045] In one embodiment, the protective layer 400 includes a winding insulation layer 410 that wraps around the exterior of a plurality of first flat wires 310 and a plurality of second flat wires 320.

[0046] In one embodiment, the protective layer 400 includes an in-groove paint layer 420 disposed between two adjacent first flat wires 310, between two adjacent second flat wires 320, and between the first flat wires 310 and the second flat wires 320.

[0047] In one embodiment, the protective layer 400 includes a slot wall insulation layer 430 disposed on the inner wall of the stator slot 101.

[0048] In this configuration, multiple first flat wires 310 and second flat wires 320 are made of copper conductors. The winding insulation layer 410 covers the outer periphery of the copper conductors. The slot varnish layer 420 fills the gaps in the slot and contacts the winding insulation layer 410. The slot wall insulation layer 430 is located between the flat wire winding 300 and the inner wall of the stator slot 101.

[0049] To verify the technical effect of the motor stator structure in this invention application, a simulation comparison was conducted between the structure of this invention application and the traditional equal-size flat wire reference structure under the conditions of the same motor speed, the same inlet temperature of the cooling medium, the same total volume flow rate of the cooling medium, the same external heat dissipation boundary conditions, and the same maximum winding temperature limit.

[0050] Under unified simulation conditions, four simulation comparison groups were set up. Each simulation comparison group is used to illustrate the thermally limited output capability, loss level of flat wire winding 300, maximum temperature or hot spot temperature of flat wire winding 300, and temperature distribution between the first flat wire 310 and the second flat wire 320 of the stator structure of this invention under the same total volumetric flow rate of cooling medium, the same inlet temperature of cooling medium, the same motor operating state, and the same maximum winding temperature constraint. Each simulation comparison group is only used to verify the technical effect of the stator structure of this invention and does not constitute a limitation on the operation mode, power supply mode, or control mode of this invention.

[0051] In each simulation comparison group, the conductor dimensions of the first flat wire 310, the conductor dimensions of the second flat wire 320, the conductor current of the first flat wire 310, the conductor current of the second flat wire 320, the output torque, the loss of the flat wire winding 300, the maximum temperature of the flat wire winding 300, and the temperature difference between the first flat wire 310 and the second flat wire 320 were recorded. For the traditional flat wire reference structure with equal dimensions, the conductor dimensions, conductor current, and temperature results of the corresponding flat wires on the slot opening side and the corresponding flat wires on the slot bottom side were recorded. The conductor currents listed in the table are all recorded values ​​at the simulation running points under the corresponding simulation comparison group, used to characterize the current carrying state of different stator structures under the same temperature constraint.

[0052] Table 1 - Simulation Comparison Table

[0053] Among them, Comparative Group 1, Comparative Group 2, and Comparative Group 3 all adopt the dual-specification flat-wire rectangular cooling channel 102 structure of this invention; Comparative Group 4 adopts the conventional equal-size flat-wire reference structure. Through the results of Comparative Groups 1 to 4, the performance of the structure of this invention can be evaluated in terms of thermally limited output capability, conventional equal current carrying capacity, and thermally limited first turn heat load on the slot side.

[0054] Example 1: Optimization scheme for dual-specification flat-line rectangular cooling channel 102 in parallel tooth structure.

[0055] In existing parallel tooth structures, the combined effect of uniformly sized flat lines and groove boundaries easily causes the cooling channel 102 to form an inverted trapezoidal cross-section that is narrow at the groove opening and wide at the groove bottom. Figure 1 As shown. Because the slot opening side is close to the air gap, it is more affected by tooth leakage magnetic flux, spatial harmonic leakage magnetic flux, skin effect and proximity effect. The flat line on the slot opening side is often the area with the highest temperature in the slot, while the inverted trapezoidal flow channel has insufficient cooling capacity in this area.

[0056] In this embodiment, a first flat line 310 with a narrower and thinner groove opening and a second flat line 320 with a wider and deeper groove bottom are used in the parallel tooth structure. By changing the position of the two types of flat lines in the groove width and groove depth directions, the groove opening width of the cooling channel 102 is increased and the groove bottom width is relatively reduced, thereby optimizing the original inverted trapezoidal channel into a rectangular or approximately rectangular channel.

[0057] In this embodiment, the first flat wire 310 is positioned near the slot opening or near the air gap, and the second flat wire 320 is positioned near the slot bottom or away from the air gap. The conductor cross-sectional dimensions of the first flat wire 310 are 3.61mm × 1.08mm, and the conductor cross-sectional dimensions of the second flat wire 320 are 4.127mm × 1.296mm. In a conventional flat wire reference structure with equal dimensions, the conductor cross-sectional dimensions of the corresponding flat wires on both the slot opening and slot bottom sides are 3.8mm × 1.2mm. All dimensions are effective cross-sectional dimensions of the copper conductor and do not include the thickness of the protective layer 400.

[0058] Under the same cooling medium volumetric flow rate conditions, for example, maintaining a total cooling medium supply flow rate of 15 L / min in the tank, the structure of this embodiment was simulated and compared. Comparison groups 1 to 3 all adopted the dual-specification flat-wire rectangular cooling channel 102 structure of this invention, while comparison group 4 adopted a traditional equal-size flat-wire reference structure. The conductor currents in each comparison group are the recorded values ​​at the corresponding simulation operating points, used only to characterize the current carrying state under different structures and comparison conditions, and do not limit this invention to using specific current relationships, power supply methods, or control methods. The comparison results are as follows: Figure 5 As shown, Figure (a) is the temperature simulation distribution diagram of comparison group 1, Figure (b) is the temperature simulation distribution diagram of comparison group 2, Figure (c) is the temperature simulation distribution diagram of comparison group 3, and Figure (d) is the temperature simulation distribution diagram of comparison group 4.

[0059] Table 2 - Experimental data of each comparative group in Example 1

[0060] As shown in Table 2, under the condition that the maximum winding temperature is basically the same, the output torque of Comparison Group 1 is 7.16% higher than that of Comparison Group 4 with the traditional equal-sized flat wire reference structure. Meanwhile, the temperature difference between the first flat wire 310 and the second flat wire 320 in Comparison Group 1 is only 0.13℃, significantly smaller than the temperature difference between the slot opening side and the slot bottom side in Comparison Group 4. This result indicates that this embodiment, through structural matching between the first flat wire 310, the second flat wire 320, and the rectangular cooling channel 102, can improve the output torque under the same temperature evaluation benchmark and significantly improve the temperature distribution between the slot opening side and the slot bottom side.

[0061] In Comparison Group 2, the first flat wire 310 and the second flat wire 320 carry the same conductor current. Table 2 shows that the output torque of this comparison group is lower than that of Comparison Group 4, and the temperature difference between the first flat wire 310 and the second flat wire 320 is higher than that of Comparison Group 4. This result indicates that when using an equal current carrying method, the heat load distribution of the dual-specification flat wire structure is not sufficiently balanced, and its heat-limited output advantage is not obvious. Comparison Group 2 serves as a reference under equal current conditions, further illustrating that the structural effect of this embodiment needs to be evaluated in conjunction with the dimensional differences between the first flat wire 310 and the second flat wire 320, the distribution of heat sources within the slot, and the spatial matching relationship of the cooling channel 102.

[0062] In comparison group 3, the loss density of the critical first turn on the slot side is not higher than or close to the loss density of the corresponding critical first turn on the slot side in the conventional equal-size flat wire reference structure. As shown in Table 2, under this constraint, the output torque of the structure of the present invention is 6.52% higher than that of comparison group 4, and the highest winding temperature is not higher than that of comparison group 4. This result indicates that the torque increase in this embodiment is not achieved by significantly increasing the thermal load of the critical first turn on the slot side, but rather by maintaining the safe boundary of the thermal load on the slot side while improving conductor utilization through the second flat wire 320 on the slot bottom side and improving the temperature distribution within the slot through the rectangular cooling channel 102.

[0063] Furthermore, while the losses of the flat wire windings 300 in Comparative Groups 1 and 3 are higher than those in Comparative Group 4, their maximum winding temperatures are still not higher. This indicates that, under higher output torque and higher current carrying capacity, this embodiment can still maintain winding temperature constraints through the matching of the cooling channel 102 and the arrangement of dual-specification flat wires. Therefore, this embodiment does not simply increase losses to gain torque, but rather improves the torque output capability under the same temperature evaluation benchmark.

[0064] Therefore, in the parallel tooth structure, this embodiment can transform the cooling channel 102 from an inverted trapezoid or approximately inverted trapezoid to a rectangle or approximately rectangle by the size difference between the first flat wire 310 and the second flat wire 320; at the same time, it improves the temperature distribution between the first flat wire 310 and the second flat wire 320, and increases the motor output torque under the same cooling medium volume flow rate and the same temperature evaluation benchmark.

[0065] Example 2: Optimization scheme for trapezoidal grooves and double-specification flat-line rectangular cooling channels 102 in parallel groove structure In existing parallel slot structures, the cooling channel 102 is relatively easy to form a rectangular or near-rectangular cross-section. However, simple parallel slots may result in an unreasonable tooth width distribution between adjacent stator teeth 120, leading to insufficient tooth area utilization, excessively high local magnetic flux density, or limited effective slot area. Figure 2 As shown.

[0066] In this embodiment, the stator slot 101 is optimized into a trapezoidal slot or a partially trapezoidal slot based on the parallel slot structure, and is matched and arranged with two specifications of flat wires, namely the first flat wire 310 and the second flat wire 320. The trapezoidal slot is used to improve the utilization rate of the tooth area and the magnetic circuit distribution. The dual-specification flat wire is used to adapt to the changes in the width of the slot, reduce the loss on the slot opening side, and improve the utilization rate of the conductor on the bottom side of the slot. The rectangular cooling channel 102 is used to maintain the uniformity of the cooling medium flow and heat exchange conditions in the slot.

[0067] In this embodiment, the first flat wire 310 is positioned near the slot opening or near the air gap, and the second flat wire 320 is positioned near the slot bottom or away from the air gap. The conductor cross-sectional dimensions of the first flat wire 310 are 3.8mm × 1.2mm, and the conductor cross-sectional dimensions of the second flat wire 320 are 4.56mm × 1.296mm. In a conventional flat wire reference structure with equal dimensions, the conductor cross-sectional dimensions of the corresponding flat wires on both the slot opening and slot bottom sides are 3.8mm × 1.2mm. All dimensions are effective cross-sectional dimensions of the copper conductor and do not include the thickness of the protective layer 400.

[0068] Under the same cooling medium volumetric flow rate, this embodiment can adjust the slope of the trapezoidal slot wall, the size ratio of the two types of flat wires, and the cross-sectional shape of the cooling channel 102 to make the highest winding temperature the same as or similar to that of the standard parallel slot flat wire scheme, while simultaneously increasing the motor output torque. The comparison results are as follows: Figure 6 As shown, Figure (a) is the temperature simulation distribution diagram of comparison group 1, Figure (b) is the temperature simulation distribution diagram of comparison group 2, Figure (c) is the temperature simulation distribution diagram of comparison group 3, and Figure (d) is the temperature simulation distribution diagram of comparison group 4. Table 3 - Experimental data of each comparative group in Example 2

[0069] As shown in Table 3, under the condition that the maximum winding temperature is basically the same, the output torque of Comparison Group 1 is 7.83% higher than that of Comparison Group 4 with the traditional equal-sized flat wire reference structure, and the maximum winding temperature is not higher than that of Comparison Group 4. Meanwhile, the temperature difference between the first flat wire 310 and the second flat wire 320 in Comparison Group 1 is only 1.22 ℃, significantly smaller than the temperature difference between the slot opening side and the slot bottom side in Comparison Group 4. This result indicates that this embodiment, through structural matching between the first flat wire 310, the second flat wire 320, and the rectangular cooling channel 102, can improve the output torque under the same temperature constraints and improve the temperature distribution between the slot opening side and the slot bottom side.

[0070] In Comparison Group 2, the first flat wire 310 and the second flat wire 320 carry the same conductor current. Table 3 shows that the output torque of this comparison group is not significantly different from that of Comparison Group 4, while the losses of the flat wire winding 3004 and the temperature difference between the two types of flat wires are higher than in Comparison Group 4. This result indicates that when using only the equal current carrying method, the heat load distribution of the dual-specification flat wire structure is not sufficiently balanced, and its torque enhancement advantage is not significant. Comparison Group 2, as a reference under equal current conditions, further illustrates that the structural effect of this embodiment needs to be evaluated in conjunction with the size differences of the first flat wire 310 and the second flat wire 320, the distribution of heat sources within the slot, and the spatial matching relationship of the cooling channel 102.

[0071] In comparison group 3, the loss density of the critical first turn on the slot side is not higher than or close to the loss density of the corresponding critical first turn on the slot side in the conventional equal-size flat wire reference structure. As shown in Table 3, under this constraint, the output torque of the structure of the present invention is 6.19% higher than that of comparison group 4, and the highest winding temperature is not higher than that of comparison group 4. This result indicates that the torque increase in this embodiment is not achieved by significantly increasing the thermal load of the critical first turn on the slot side, but rather by maintaining the safe boundary of the thermal load on the slot side while improving conductor utilization through the second flat wire 320 on the slot bottom side and improving the temperature distribution within the slot through the rectangular cooling channel 102.

[0072] Furthermore, while the losses of the flat wire winding 3004 in Comparative Groups 1 and 3 are higher than those in Comparative Group 4, their maximum winding temperature is still not higher. This indicates that, under higher output torque and higher current carrying capacity, this embodiment can still maintain winding temperature constraints through the matching of the cooling channel 102 and the arrangement of dual-specification flat wires. Therefore, this embodiment does not simply increase losses to gain torque, but rather improves the thermally limited output capability under the same temperature evaluation benchmark.

[0073] Therefore, in the parallel slot structure, this embodiment can improve the utilization rate of the bottom conductor while maintaining the rectangularity of the cooling channel 102, improve the temperature distribution between the first flat wire 310 and the second flat wire 320, and improve the motor output torque under the same cooling medium volume flow rate and the same temperature evaluation standard.

[0074] Compared with existing technologies: 1. From a thermal management perspective, the flat line on the slot side is close to the air gap and is a typical strong heat source area. This invention releases the flow channel space through the narrow and thin first flat line 310 on the slot side, so that the cooling flow channel 102 in the middle forms a rectangular or approximately rectangular cross section, thereby improving the flow area of ​​the cooling medium on the slot side and the local heat exchange capacity.

[0075] 2. From the perspective of electromagnetic loss, after the cross-sectional thickness or width of the first flat wire 310 is reduced, the size of its equivalent eddy current loop in the alternating magnetic field is reduced, which can reduce the AC additional loss on the slot side; the second flat wire 320 is arranged on the bottom side of the slot and is relatively less affected by high-frequency leakage magnetic field, so a larger conductor cross-sectional area can be used to reduce DC resistance and DC copper loss.

[0076] 3. From the perspective of structural torque enhancement, traditional flat wire structures of the same specification are often limited by hot spots at the slot opening, making it difficult to further increase the overall current rating. This invention reduces hot spots at the slot opening, increases the cross-sectional area of ​​the conductor on the bottom side of the slot, and improves the heat transfer uniformity of the flow channel, enabling the motor to achieve a higher thermal margin without increasing the cooling flow rate. This thermal margin can be used to increase the allowable phase current, increase the thermally limited continuous torque, or reduce the maximum temperature rise and improve reliability at the same torque.

[0077] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A motor stator structure compatible with parallel teeth and parallel slots, characterized in that, include: A stator core having stator slots; The flat wire winding includes a plurality of first flat wires and a plurality of second flat wires. The plurality of first flat wires and the plurality of second flat wires are symmetrically arranged radially in the stator slots of the stator core. The first flat wires are positioned close to the slot opening of the stator slot, and the second flat wires are positioned away from the slot opening of the stator slot. The width of the first flat wires is smaller than the width of the second flat wires. Double cone or rectangular cooling channels are formed between the plurality of first flat wires and between the plurality of second flat wires.

2. The motor stator structure compatible with parallel teeth and parallel slots according to claim 1, characterized in that, The stator core includes a stator yoke and multiple stator teeth, one end of each stator tooth is connected to the stator yoke, and a stator slot is formed between any two adjacent stator teeth.

3. The motor stator structure compatible with parallel teeth and parallel slots according to claim 2, characterized in that, The two side walls of the stator teeth are arranged in parallel, and the cooling channel is a double cone.

4. The motor stator structure compatible with parallel teeth and parallel slots according to claim 3, characterized in that, The stator slot has a center line extending in the radial direction of the stator core, the distances from the plurality of first flat wires to the center line increase sequentially in the radial direction of the stator core, and the distances from the plurality of second flat wires to the center line increase sequentially in the radial direction of the stator core.

5. The motor stator structure compatible with parallel teeth and parallel slots according to claim 2, characterized in that, The two side walls of the stator slot are arranged in parallel, and the cooling channel is rectangular.

6. The motor stator structure compatible with parallel teeth and parallel slots according to claim 5, characterized in that, The stator slot has a centerline extending in the radial direction of the stator core, and the distances from the centerline to the plurality of first flat wires and the plurality of second flat wires are all equal.

7. The motor stator structure compatible with parallel teeth and parallel slots according to claim 1, characterized in that, It also includes a protective layer disposed within the stator slot.

8. The motor stator structure compatible with parallel teeth and parallel slots according to claim 7, characterized in that, The protective layer includes a winding insulation layer that wraps around the exterior of the plurality of first flat wires and the plurality of second flat wires.

9. The motor stator structure compatible with parallel teeth and parallel slots according to claim 7, characterized in that, The protective layer includes an in-groove paint layer disposed between two adjacent first flat wires, between two adjacent second flat wires, and between the first flat wire and the second flat wire.

10. The motor stator structure compatible with parallel teeth and parallel slots according to claim 7, characterized in that, The protective layer includes a slot wall insulation layer disposed on the inner wall of the stator slot.

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