Litz wire, stator winding and motor

Abstract

The utility model discloses a Litz wire, a stator winding and a motor, and relates to the technical field of motors, the Litz wire comprises a plurality of strands of basic wires, the plurality of strands of basic wires are twisted into a whole, and each basic wire comprises a metal inner core, a graphene layer wrapping the metal inner core and an insulating layer wrapping the graphene layer; according to the technical scheme provided by the utility model, the technical effects of improving conductivity, reducing direct current loss, reducing heating, reducing skin effect and proximity effect under a high-frequency working condition, improving uniformity of current distribution, reducing alternating current loss and improving efficiency of the motor can be achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a litz wire, a stator winding and a motor. Background Art

[0002] New energy vehicle motors are trending towards higher speed, higher efficiency, and higher power density, placing higher demands on the electrical conductivity, thermal conductivity, and strength of electromagnetic wire. Existing flat motor wires have relatively low conductivity, resulting in significant heat generation and high current loss. Furthermore, under high-frequency operating conditions, they suffer from skin and proximity effects, which reduce motor efficiency. Utility Model Content

[0003] The main purpose of the utility model is to propose a Litz wire, a stator winding and a motor, aiming to improve the problems of relatively low conductivity of the existing motor flat wire, severe heat generation, large current loss, and the existence of skin effect and proximity effect under high-frequency working conditions, which will reduce the efficiency of the motor.

[0004] To achieve the above-mentioned purpose, the Litz wire proposed in the present invention includes multiple basic conductors, which are twisted into a whole. Each basic conductor includes a metal core, a graphene layer covering the metal core, and an insulating layer covering the graphene layer.

[0005] In one embodiment, the metal inner core is a round wire.

[0006] In one embodiment, the diameter of the metal inner core is 0.05 mm to 1 mm.

[0007] In one embodiment, the metal inner core is made of copper alloy or aluminum alloy.

[0008] In one embodiment, the thickness of the graphene layer is 1 nm to 20 nm; and / or,

[0009] The insulating layer is polyimide paint or polyesterimide paint; and / or,

[0010] The cross section of the basic wire is circular.

[0011] In one embodiment, the cross section of the litz wire is rectangular.

[0012] In one embodiment, the Litz wire is formed by twisting a plurality of basic conductors into a single turn.

[0013] In one embodiment, the tightness of the litz wire is greater than or equal to 90%.

[0014] The utility model also provides a stator winding, comprising the above-mentioned Litz wire.

[0015] The utility model also provides a motor, comprising the above-mentioned stator winding.

[0016] In the technical solution of the present invention, the graphene layer is coated on the metal battery core to form the basic wire of the metal-graphene composite material, and then multiple strands of the basic wire of the metal-graphene composite material are used to form a Litz wire. This can improve electrical conductivity, reduce DC loss, reduce heat generation, reduce skin effect and proximity effect under high-frequency working conditions, improve the uniformity of current distribution, reduce AC loss, and thus improve the efficiency of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0018] Figure 1 A structural diagram of an embodiment of a Litz wire provided by the present invention;

[0019] Figure 2 for Figure 1 Schematic diagram of the structure of the basic conductor.

[0020] Description of Figure Numbers:

[0021] 10. Litz wire; 1. Base conductor; 11. Metal inner core; 12. Graphene layer; 13. Insulation layer.

[0022] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only 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 making creative efforts shall fall within the scope of protection of the present invention.

[0024] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0025] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] New energy vehicle motors are trending towards higher speed, higher efficiency, and higher power density, placing higher demands on the electrical conductivity, thermal conductivity, and strength of electromagnetic wire. Existing flat motor wires have relatively low conductivity, resulting in significant heat generation and high current loss. Furthermore, under high-frequency operating conditions, they suffer from skin and proximity effects, which reduce motor efficiency.

[0027] In view of this, the present invention proposes a litz wire, a stator winding and a motor, which can improve the electrical conductivity, reduce DC loss, reduce heat generation, and reduce the skin effect and proximity effect under high-frequency working conditions, improve the uniformity of current distribution, reduce AC loss, and thus improve the efficiency of the motor. Figure 1 A structural diagram of an embodiment of a Litz wire provided by the present invention; Figure 2 for Figure 1 Schematic diagram of the structure of the basic conductor.

[0028] See also Figures 1 to 2 In one embodiment of the present invention, the Litz wire 10 includes a plurality of basic conductors 1, which are twisted into a whole. Each of the basic conductors 1 includes a metal core 11, a graphene layer 12 covering the metal core 11, and an insulating layer 13 covering the graphene layer 12.

[0029] In the technical solution of the present invention, the graphene layer 12 is coated on the metal battery core to form the basic conductor 1 of the metal-graphene composite material, and then multiple strands of the basic conductor 1 of the metal-graphene composite material are used to form the Litz wire 10. This can improve the electrical conductivity, reduce DC loss, reduce heat generation, reduce the skin effect and proximity effect under high-frequency working conditions, improve the uniformity of current distribution, reduce AC loss, and thus improve the efficiency of the motor.

[0030] It is understood that the cross-section of the metal core 11 can be rectangular, circular, elliptical, or irregular, etc. In the embodiment of the present invention, the metal core 11 is a round wire. The use of a round wire for the metal core 11 is beneficial for improving the tightness of the litz wire 10 and facilitating the coating of the graphene layer 12.

[0031] In an embodiment of the present invention, the diameter of the metal inner core 11 is 0.05 mm to 1 mm. The diameter of the metal inner core 11 within the above range is beneficial for improving the conductivity of the litz wire 10, reducing DC loss and heat generation, and also for reducing the skin effect and proximity effect under high-frequency conditions, improving the uniformity of current distribution, and reducing AC loss. The diameter of the metal inner core 11 can be 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, or 1 mm, etc.

[0032] In an embodiment of the present invention, the metal inner core 11 is made of a copper alloy or an aluminum alloy. This facilitates the molding of the Litz wire 10 and improves the electrical conductivity of the Litz wire 10. Furthermore, the copper alloy of the metal inner core 11 improves both the electrical conductivity and the mechanical strength of the Litz wire 10.

[0033] In an embodiment of the present invention, the thickness of the graphene layer 12 is 1 nm to 20 nm. The thickness of the graphene layer 12 is within the above range, which is beneficial to improving the conductivity of the Litz wire 10, reducing DC loss, reducing heat generation, and also beneficial to reducing the skin effect and proximity effect under high-frequency working conditions, improving the uniformity of current distribution, and reducing AC loss; the thickness of the graphene layer 12 can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm, etc. It can be understood that the graphene layer 12 can be prepared on the metal core 11 by chemical vapor deposition (CVD), so that graphene grows uniformly and continuously on the surface of the metal core 11 to form the graphene layer 12, which can ensure the quality of the graphene layer 12.

[0034] In an embodiment of the present invention, the diameter of the metal inner core 11 is 0.05 mm to 1 mm, and the thickness of the graphene layer 12 is 1 nm to 20 nm. The diameter of the metal inner core 11 and the thickness of the graphene layer 12 within the above ranges further improve the electrical conductivity of the litz wire 10, reduce DC losses, and reduce heat generation. They also further reduce the skin effect and proximity effect under high-frequency operating conditions, improve the uniformity of current distribution, and reduce AC losses.

[0035] In the embodiment of the present invention, the insulating layer 13 is polyimide paint or polyesterimide paint. The insulating layer 13 is made of polyimide paint or polyesterimide paint, which is beneficial to improving the insulation performance, heat resistance, mechanical performance and stability of the litz wire 10.

[0036] It is understood that the cross-section of the base conductor 1 can be rectangular, circular, elliptical, or irregular, etc. In the embodiment of the present invention, the cross-section of the base conductor 1 is circular. The circular cross-section of the base conductor 1 is conducive to improving the compactness of the Litz wire 10.

[0037] It is understood that the cross-section of the Litz wire 10 can be rectangular, circular, elliptical, or irregular, etc.; in the embodiment of the present invention, the cross-section of the Litz wire 10 is rectangular. The rectangular cross-section of the Litz wire 10 can reduce the gaps between the Litz wires 10 when used in stator windings, increase the stator slot fill rate, and thus increase the power density of the motor.

[0038] In an embodiment of the present invention, the Litz wire 10 is formed by twisting the multiple strands of base conductors 1 in a single-turn manner. This single-turn twisting method improves the reliability, strength, and anti-interference capabilities of the Litz wire 10. It should be noted that single-turn twisting refers to twisting multiple strands of the same or different diameters together in a specific direction and according to a specific rule to form a single core.

[0039] In an embodiment of the present invention, the compactness of the litz wire 10 is greater than or equal to 90%. The compactness of the litz wire 10 being within the above range is beneficial for reducing the skin effect and proximity effect under high-frequency conditions, improving the uniformity of current distribution, reducing AC losses, and also beneficial for improving the mechanical strength of the litz wire 10.

[0040] It should be noted that, in an embodiment of the present invention, the preparation method of the Litz wire 10 can be: the multi-strand basic conductor 1 is twisted in a single-winding manner to form a Litz wire 10 with a circular cross-section, and the twisted wire filling coefficient is greater than or equal to 85%, and then the Litz wire 10 with a circular cross-section is squared by a mold to form a Litz wire 10 with a rectangular cross-section, and the compactness of the Litz wire 10 after square pressing is greater than or equal to 90%.

[0041] The present invention also proposes a stator winding, which includes a Litz wire 10. The specific structure of the Litz wire 10 refers to the above embodiment. Since the stator winding adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0042] The stator winding using the litz wire 10 of the present invention can achieve a stator slot fill rate of 45% to 65%, and an AC conductivity of 106% to 108% IACS, 104% to 106% IACS, 97% to 99% IACS, and 89% to 91% IACS at 1 kHz, 10 kHz, 50 kHz, and 100 kHz, respectively.

[0043] The stator winding of the round litz wire 10 made of round metal conductor can have a stator slot fill rate of 35% to 45%, and the AC conductivity at 1 kHz, 10 kHz, 50 kHz, and 100 kHz can reach 98% IACS to 100% IACS, 95% IACS to 97% IACS, 88% IACS to 90% IACS, and 76% IACS to 78% IACS, respectively.

[0044] With flat wire stator winding, the stator slot fill rate can be 55% to 75%, and the AC conductivity at 1kHz, 10kHz, 50kHz, and 100kHz can reach 100% IACS to 102% IACS, 93% IACS to 95% IACS, 81% IACS to 83% IACS, and 54% IACS to 56% IACS, respectively.

[0045] The stator winding adopts high-conductivity flat wire, and the stator slot fill rate can be 55% to 75%. The AC conductivity at 1kHz, 10kHz, 50kHz and 100kHz can reach 103%IACS to 105%IACS, 99%IACS to 101%IACS, 89%IACS to 91%IACS and 72%IACS to 74%IACS respectively.

[0046] When the litz wire 10 of the present invention is used in a stator winding, the stator slot fill rate and the AC conductivity under high-frequency working conditions can be improved.

[0047] The present invention also proposes a motor, which includes a stator winding. The specific structure of the stator winding refers to the above-mentioned embodiment. Since this motor adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0048] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A litz wire, characterized in that The invention comprises a plurality of basic conductors which are twisted to form a whole. Each basic conductor comprises a metal inner core, a graphene layer covering the metal inner core and an insulating layer covering the graphene layer.

2. The litz wire according to claim 1, wherein The metal inner core is a round wire.

3. The litz wire according to claim 2, wherein The diameter of the metal inner core is 0.05 mm to 1 mm.

4. The litz wire according to claim 1, wherein The material of the metal inner core is copper alloy or aluminum alloy.

5. The litz wire according to any one of claims 1 to 4, characterized in that The thickness of the graphene layer is 1 nm to 20 nm; and / or, The insulating layer is polyimide paint or polyesterimide paint; and / or, The cross section of the basic wire is circular.

6. The litz wire according to claim 1, wherein The cross section of the litz wire is rectangular.

7. The litz wire according to claim 1, wherein The Litz wire is formed by twisting a plurality of basic conductors in a single turn.

8. The litz wire according to claim 1, wherein The compactness of the litz wire is greater than or equal to 90%.

9. A stator winding, characterized in that: Comprising the litz wire according to any one of claims 1 to 8.

10. A motor, characterized in that: Comprising the stator winding according to claim 9.

Images