A cooling structure of a high-speed permanent magnet motor with a back-wound winding and the motor

Abstract

The application relates to the technical field of high-speed permanent magnet motors, in particular to a cooling structure of a back-wound winding high-speed permanent magnet motor and the motor. The cooling structure uses a heat pipe to replace part of the outer teeth of a stator core, reduces the thermal resistance of heat transfer from the inside of the back-wound winding high-speed permanent magnet motor to the liquid cooling machine shell, strengthens the cooling effect of the stator core and the back-wound winding of the back-wound winding high-speed permanent magnet motor without affecting the electromagnetic performance of the back-wound winding high-speed permanent magnet motor and without increasing the volume, greatly reduces the overall temperature of the motor, and promotes the application of the back-wound winding high-speed permanent magnet motor to the high-power high-speed field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-speed permanent magnet motor, in particular to a cooling structure of a back-wound winding high-speed permanent magnet motor and the motor. BACKGROUND

[0002] With the development of emerging fields such as new energy vehicles, more electric / all-electric aircraft, more electric / all-electric ships, there is a large demand for high-speed permanent magnet motors. High-speed permanent magnet motors have been widely concerned due to their advantages of high power density, high efficiency, small size and light weight. However, the existing high-speed permanent magnet motor generally adopts a lap winding. Due to the long end of the lap winding, the axial length of the motor is increased, which gradually highlights the rotor dynamics problem and limits the increase of the rotational speed. In comparison, the back-wound winding has a special structure of winding around the inner and outer sides of the stator core, which makes the axial length of the winding end very short and the stator axial size very compact. Therefore, the back-wound winding has great application potential in the field of high-speed permanent magnet motors.

[0003] However, the small size and high power density of the back-wound winding high-speed permanent magnet motor also brings the problems of limited heat dissipation area and serious heating. In addition, due to the use of the back-wound winding, the height of the outer teeth of the stator core and the outer back-wound winding in the radial direction is additionally increased, so that when the back-wound winding high-speed permanent magnet motor uses the traditional heat conduction from the stator core to the liquid cooling shell and uses the cooling liquid in the liquid cooling shell to dissipate heat, the heat transfer path of the heat transfer of the heat in the motor to the liquid cooling shell in the radial direction is lengthened, that is, the thermal resistance is increased, which further aggravates the heating of the back-wound winding high-speed permanent magnet motor. SUMMARY

[0004] In a first aspect, the purpose of the present application is to provide a cooling structure of a back-wound winding high-speed permanent magnet motor. By using heat pipes to replace part of the outer teeth of the stator core, the thermal resistance of the heat transfer of the heat in the back-wound winding high-speed permanent magnet motor to the liquid cooling shell is reduced. Without affecting the electromagnetic performance of the back-wound winding high-speed permanent magnet motor and without increasing the volume, the cooling effect of the stator core and the back-wound winding of the back-wound winding high-speed permanent magnet motor is strengthened.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] A cooling structure of a back-wound winding high-speed permanent magnet motor, comprising: heat pipes, the heat pipes imitate the shape of the outer teeth of the stator core of the back-wound winding high-speed permanent magnet motor, and when at least one heat pipe replaces the outer teeth of the stator core and is installed on the outer circumferential side wall of the stator core:

[0007] If the heat pipe is one, the heat pipe and the adjacent outer teeth of the stator core form an outer slot;

[0008] If the heat pipe is multiple, when the heat pipe is adjacent to another heat pipe, the heat pipe and the adjacent another heat pipe form an outer groove; and at least one heat pipe is adjacent to the outer tooth of the stator core, and the heat pipe and the adjacent outer tooth of the stator core form an outer groove.

[0009] The condensation section of the heat pipe exchanges heat with the liquid cooling machine shell of the back-wound winding high-speed permanent magnet motor.

[0010] In some disclosures, the heat pipe is detachably fixedly connected between the outer circumferential side wall of the stator core.

[0011] In some disclosures, the heat pipe has a clamping part or a clamping groove at the lower end, and the outer circumferential side wall of the corresponding stator core has a matching clamping groove or clamping part; the heat pipe and the outer circumferential side wall of the stator core are connected through the matching of the clamping groove and the clamping part.

[0012] In some disclosures, the gap between the clamping part and the clamping groove is filled with heat-conducting silica gel.

[0013] In some disclosures, the length of the heat pipe is equal to the length of the stator core, and the axial end faces of the two sides of the stator core are flush with the end faces of the heat pipe.

[0014] In some disclosures, the length of the heat pipe is greater than the length of the stator core, and the heat pipe beyond the axial end faces of the two sides of the stator core forms a half-enclosing structure to the end part of the back-wound winding.

[0015] In some disclosures, the outer side wall of the condensation section of the heat pipe is formed with a circular arc surface matching the inner wall of the liquid cooling machine shell, and the circular arc surface is attached to the inner wall of the liquid cooling machine shell.

[0016] The second aspect is to provide a back-wound winding high-speed permanent magnet motor, which uses a heat pipe to replace part of the outer teeth of the stator core, reduces the thermal resistance of heat transfer from the inside of the back-wound winding high-speed permanent magnet motor to the liquid cooling machine shell, and strengthens the efficient cooling of the stator core and the back-wound winding of the back-wound winding high-speed permanent magnet motor without affecting the electromagnetic performance and increasing the volume.

[0017] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0018] A back-wound winding high-speed permanent magnet motor, comprising the cooling structure of the first aspect, when at least one heat pipe replaces the outer tooth of the stator core and is installed on the outer circumferential side wall of the stator core, the top end of the cooling structure is attached to the inner wall of the liquid cooling machine shell;

[0019] The liquid cooling machine shell has a liquid cooling liquid channel, and the liquid cooling channel is filled with cooling liquid.

[0020] The cooling structure conducts heat on the stator core to the cooling liquid in the liquid cooling machine shell, and the cooling liquid is cooled.

[0021] In some disclosures, the heat pipes are arranged in a structure alternating with the circumferential spaces formed by the outer teeth of the stator core.

[0022] In some disclosures, the number of heat pipes is equal to the number of the outer teeth of the adjacent stator core.

[0023] The present application has at least the following advantages:

[0024] 1. The heat pipes replace part of the outer teeth of the conventional back-wound winding high-speed permanent magnet motor. Due to the excellent heat conduction ability of the heat pipes, the thermal resistance of the heat transfer of the internal heat of the back-wound winding high-speed permanent magnet motor to the liquid cooling shell is effectively reduced, so that the heat concentrated in the stator core and the winding can be quickly transferred to the liquid cooling shell and the heat can be quickly removed by the cooling liquid. The heat pipes can also quickly transfer the heat of the outer winding in the outer slot of the stator to the liquid cooling shell, and the combined effect of the two aspects can greatly reduce the temperature rise of the back-wound winding high-speed permanent magnet motor.

[0025] 2. When the axial length of the heat pipe is greater than the stator core, the part exceeding the axial end surface of the stator core can also quickly transfer the heat of the end part of the back-wound winding to the cooling liquid in the liquid cooling shell, avoiding the high temperature of the end part of the back-wound winding due to heat accumulation.

[0026] 3. Since the outer teeth of the back-wound winding high-speed permanent magnet motor and the outer back-wound winding do not contribute to the electromagnetic performance of the motor, they only play a role in supporting the structure and connecting the effective winding of the air gap side. Therefore, when using heat pipes to replace part of the outer teeth, they can play a role in assisting the support of the stator in structure, and have little effect on electromagnetic performance.

[0027] Of course, any product implementing the present application does not necessarily need to achieve all the advantages above. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a three-dimensional view of the cooling structure of the back-wound winding high-speed permanent magnet motor of the present application;

[0029] Figure 2 is an end view of the overall structure of the back-wound winding high-speed permanent magnet motor of the present application;

[0030] Figure 3 is a three-dimensional view of the stator of the back-wound winding high-speed permanent magnet motor of the present application;

[0031] Figure 4 is an assembly view of the heat pipe with a length greater than the stator core installed on the stator core;

[0032] Figure 5 is an assembly view of the continuous heat pipe group installed on the stator core;

[0033] Figure 6 A diagram showing an assembly of heat pipes of the same length as the stator core installed on the stator core.

[0034] Figure 7 A three-dimensional view of a stator core with slots;

[0035] Figure 8 A three-dimensional view of a heat pipe with a locking mechanism;

[0036] Figure 9 A cross-sectional view of a heat pipe with a locking mechanism;

[0037] Figure 10 This is a schematic diagram illustrating the working principle of a heat pipe.

[0038] Figure 11 To adopt Figure 3 The magnetic field distribution diagram of the high-speed permanent magnet motor with the heat pipe structure shown;

[0039] Figure 12 This is a diagram showing the magnetic field distribution of a conventional back-wound high-speed permanent magnet motor.

[0040] Figure 13 To adopt Figure 3 The magnetic flux density distribution cloud map of the high-speed permanent magnet motor with the heat pipe structure shown.

[0041] Figure 14 This is a magnetic flux density distribution cloud map of a conventional back-wound high-speed permanent magnet motor.

[0042] Figure 15 To adopt Figure 3 The no-load back EMF waveform of the high-speed permanent magnet motor with the heat pipe structure shown.

[0043] Figure 16 This is the no-load back EMF waveform of a conventional back-wound high-speed permanent magnet motor.

[0044] Figure 17 To adopt Figure 3 The torque curve of the high-speed permanent magnet motor with the heat pipe structure shown.

[0045] Figure 18 The torque curve is for a conventional back-wound high-speed permanent magnet motor.

[0046] Figure 19 This is a diagram showing the winding temperature distribution of a conventional back-wound high-speed permanent magnet motor.

[0047] Figure 20 This is a temperature distribution diagram of the stator core of a conventional back-wound high-speed permanent magnet motor.

[0048] Figure 21Whole temperature distribution of high-speed permanent magnet motor with conventional back-wound winding

[0049] Figure 22 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 1 Figure 6

[0050] Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 2 Figure 23 Figure 6 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 3

[0051] Figure 24 Figure 6 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 4

[0052] Figure 25 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 5 Figure 4

[0053] Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 6 Figure 26 Figure 4 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 7

[0054] Figure 27 Figure 4 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 8

[0055] Figure 28 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 9 Figure 5

[0056] Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 10 Figure 29 Figure 5 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 11

[0057] Figure 30 Figure 5 Whole temperature distribution of high-speed permanent magnet motor with heat pipe structure shown in Fig. 12

[0058] 1, liquid cooling shell; 2, liquid cooling liquid; 3, stator core; 31, clamping groove; 4, outer tooth; 5, stator inner tooth; 6, outer slot; 7, inner slot; 8, back-wound winding; 9, back-wound winding end; 10, heat pipe; 101, condensation section of heat pipe 10; 102, evaporation section of heat pipe 10; 103, pipe wall of heat pipe 10; 104, cavity of heat pipe 10; 105, capillary wick of heat pipe 10; 106, clamping part of heat pipe 10; 11, rotating shaft; 12, permanent magnet; 13, sheath DETAILED DESCRIPTION

[0059] ​​​​​​The technical solutions in the embodiments of the present disclosure will be clearly and completely described in combination with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present disclosure.

[0060] The high-speed permanent magnet motor with back-wound windings generally comprises a stator core 3, the stator inner teeth 5 and the outer teeth 4 of the stator core 3 are respectively provided with axially distributed inner slots 7 and outer slots 6, and the windings are back-wound in the inner slots 7 and the outer slots 6. Specifically, one side of each back-wound coil constituting the back-wound windings 8 is in the inner slot 7, and the other side is in the opposite outer slot 6 of the inner slot 7. In the prior art, the positions of the inner slots 7 between the outer slots 6 and the stator inner teeth 5 of the stator core 3 correspond to each other. The inner slots 7 and the outer slots 6 on the inner side and the outer side of the stator core 3 can be designed to have different tooth slot numbers, but the number of the inner slots 7 should be an integer multiple of the number of the outer slots 6. Of course, in some cases, the number of the inner slots 7 can be equal to the number of the outer slots 6. The outer teeth 4 and the outer back-wound windings 8 of the high-speed permanent magnet motor with back-wound windings do not contribute to the electromagnetic performance of the high-speed permanent magnet motor with back-wound windings. They only play a role in supporting the structure and connecting the effective windings on the air gap side. Of course, in some cases, insulation paper is laid in the outer slots 6 and the inner slots 7, or the outer surfaces of the inner slots 7 and the outer slots 6 are entirely sprayed with insulating materials, and then the back-wound windings 8 with high slot fill factors are wound in the outer slots 6 and the inner slots 7.

[0061] The heat pipe 10 generally has a cavity 104 wrapped by a shell. The inner wall of the cavity 104 is attached with a capillary wick 105, and the capillary wick 105 is filled with a liquid working medium. One end of the heat pipe 10 in contact with a component that needs to be cooled is the evaporation section 102, and the other end in contact with the refrigerant is the condensation section 101. When one end (the evaporation section 102) of the heat pipe 10 is heated, the liquid working medium in the capillary wick vaporizes and vaporizes. The steam flows to the other end (the condensation section 101) under a small pressure difference and releases heat to condense into liquid. The liquid flows back to the evaporation section 102 along the porous material under the action of capillary force. The cycle continues, and heat is transferred from one end (the evaporation section 102) to the other end (the condensation section 101) of the heat pipe 10, achieving heat transfer. The liquid working medium is generally selected as acetone, methanol or water.

[0062] Embodiment one:

[0063] In the present application, a cooling structure of a high-speed permanent magnet motor with back-wound windings is disclosed, comprising: a heat pipe 10, the heat pipe 10 is shaped like the outer teeth 4 of the stator core 3 of the high-speed permanent magnet motor with back-wound windings, and when at least one heat pipe 10 replaces the outer teeth 4 of the stator core 3 and is installed on the outer side circumferential side wall of the stator core 3:

[0064] If the heat pipe 10 is one, the heat pipe 10 and the adjacent outer tooth 4 of the stator core 3 form an outer slot 6;

[0065] If the heat pipe 10 is multiple, when the heat pipe 10 is adjacent to another heat pipe 10, the heat pipe 10 and the adjacent another heat pipe 10 form an outer slot 6; and at least one heat pipe 10 is adjacent to the outer tooth 4 of the stator core 3, the heat pipe 10 and the adjacent outer tooth 4 of the stator core 3 form an outer slot 6;

[0066] Wherein, the condensation section of the heat pipe 10 exchanges heat with the inner side of the liquid cooling shell 1 of the back-wound winding high-speed permanent magnet motor.

[0067] That is, in this application, the heat pipe 10 is shaped like the outer tooth 4 of the stator core 3, and part of the outer tooth 4 of the stator core 3 of the back-wound winding high-speed permanent magnet motor is replaced by the heat pipe 10, so that the heat pipe 10 and the adjacent outer tooth 4 of the core form an outer slot 6; The outer slot 6 formed at this time can realize the original function, such as fixing and accommodating the back-wound winding 8; After replacing part of the outer tooth 4 of the stator core 3, the evaporation section 102 of the heat pipe 10 is in contact with the stator core 3, and the condensation section 101 of the heat pipe 10 is in contact with the liquid cooling shell 1. Due to the excellent heat conduction ability of the heat pipe 10, the thermal resistance of the heat transfer from the inside of the back-wound winding high-speed permanent magnet motor to the liquid cooling shell 1 can be effectively reduced, so that the heat concentrated in the stator core 3 and the winding can be quickly transferred to the liquid cooling shell 1, and the heat can be quickly removed by the cooling liquid; And the heat pipe 10 can also quickly transfer the heat of the outer winding in the outer slot 6 in contact with it to the liquid cooling shell 1, and the comprehensive effect of the two aspects makes the temperature rise of the back-wound winding high-speed permanent magnet motor greatly reduced; In this stage, when the heat pipe 10 is used to replace part of the outer tooth 4, it can play a supporting role in assisting the stator core 3 in structure, and has little effect on the electromagnetic performance of the back-wound winding high-speed permanent magnet motor.

[0068] In the prior art, insulation paper will also be laid in the outer slot 6 or the inner slot 7, or the outer surface of the inner slot 7 and the outer slot 6 will be sprayed with an insulating material, and then the back-wound winding 8 with high slot fill factor will be wound in the outer slot 6 and the inner slot 7; Because the thickness of the insulation paper and the insulation layer is relatively thin, the heat transfer of the winding to the stator core 3 and the heat pipe 10 is less affected, that is, it can be considered that the outer winding in the outer slot 6 is in close contact with the heat pipe 10.

[0069] As Figures 8-10As shown in the application, the heat pipe 10 imitates the shape of the outer tooth 4 of the stator core 3 of the back-wound winding high-speed permanent magnet motor, specifically, the end face parallel surface of the back-wound winding high-speed permanent magnet motor is taken as a cross section, and the heat pipe 10 has a similar cross section shape with the outer tooth 4 of the stator core 3, both of which have a similar "T" shaped cross section. The purpose is that the heat pipe 10 imitates the shape of the outer tooth 4 of the stator core 3, so that when the outer tooth 4 of the stator core 3 is replaced, the heat pipe 10 is installed on the stator core 3 and will not damage the outer slot 6 structure formed between the adjacent outer teeth 4 of the stator core 3, thereby satisfying the original function of the back-wound winding high-speed permanent magnet motor, such as the winding being back-wound in the inner slot 7 and the outer slot 6.

[0070] As shown in the application, Figures 8-10 The heat pipe 10 includes an evaporation section 102 and a condensation section 101 fixedly connected with the evaporation section 102. The heat pipe 10 has a cavity 104 wrapped by a shell, the inner wall of the cavity 104 is attached with a capillary wick 105, and the capillary wick 105 is filled with a liquid working medium. The evaporation section 102 is in contact with the stator core 3. When the evaporation section 102 of the heat pipe 10 is heated, the liquid working medium in the capillary wick vaporizes and evaporates, the steam flows to the condensation section 101 under a small pressure difference and releases heat to condense into liquid, and the liquid flows back to the evaporation section 102 along the porous material under the action of capillary force, so as to circulate continuously. Heat is transferred from the evaporation section 102 to the condensation section 101 of the heat pipe 10, and heat transfer is realized. The liquid working medium is generally selected as acetone, methanol or water. Figure 10 In the capillary wick, the arrow represents the flow direction of the liquid working medium; and the arrow of the cavity 104 represents the moving direction of the evaporated gas.

[0071] For the preparation of the heat pipe 10, the material of the pipe wall 104 of the heat pipe 10 is preferably copper, and the manufacturing process is preferably 3D printing technology, which is convenient for meeting the size requirements of different parts of the heat pipe 10 according to the needs.

[0072] 3D printing technology refers to a high-tech technology that converts a digital model into a physical entity through layer-by-layer stacking. It uses computer-aided design (CAD) software to generate a three-dimensional model, and then sends the model to a 3D printer for "printing". In the 3D printing process, the user first selects appropriate printing materials such as plastic, metal or ceramic, and then uses software to layer the design model and calculate the fine structure of each layer. Then, the 3D printer will stack the solid materials layer by layer according to the predetermined path and specifications to finally build a complete object. 3D printing technology is prior art and will not be described here.

[0073] As shown in some cases, Figure 3As shown, the length of the heat pipe 10 is greater than the length of the stator core 3, and the heat pipe 10 beyond the axial end surfaces of the stator core 3 on both sides forms a half-enclosed structure to the back-wound winding end 9; the part beyond the axial end surfaces of the stator core 3 on both sides can also quickly transfer the heat of the back-wound winding end 9 to the liquid cooling shell 1, avoiding the high temperature of the back-wound winding end 9 due to heat accumulation. At this stage, by replacing part of the stator outer tooth 4 of the conventional back-wound winding high-speed permanent magnet motor with the heat pipe 10, the heat transfer thermal resistance of the heat pipe 10 to the liquid cooling shell 1 inside the back-wound winding high-speed permanent magnet motor can be effectively reduced, so that the heat concentrated in the stator core 3 and the back-wound winding 8 can be quickly transferred to the evaporation section 102 of the heat pipe 10, and the working medium in the heat pipe 10 can be phase changed, and the heat can be transferred to the liquid cooling shell 1; at the same time, the heat pipe 10 can also transfer the heat of the outer winding in the outer slot 6 to the liquid cooling shell 1, and the comprehensive effect of the two aspects can greatly reduce the temperature difference of the back-wound winding high-speed permanent magnet motor, avoid local overheating, and reduce the temperature rise of the back-wound winding high-speed permanent magnet motor.

[0074] Of course, the contact mode of the heat pipe 10 and the liquid cooling shell 1 is that the outer side wall of the condensation section of the heat pipe 10 is formed with a circular arc surface matched with the inner wall of the liquid cooling shell 1, and the circular arc surface is attached to the inner wall of the liquid cooling shell 1.

[0075] In the present application, the heat pipe 10 replaces the outer tooth 4 of the stator core 3 and is installed on the outer circumferential side wall of the stator core 3, and in some cases, the heat pipe 10 can be directly fixed and connected between the heat pipe 10 and the stator core 3 by adhesive or welding, such as Figure 2 As shown in the overall structure diagram of the motor, the heat pipe is fixed and connected in this way.

[0076] As shown in the overall structure diagram of the motor, the heat pipe is fixed and connected in this way. Figures 6-7 As shown, the lower end of the heat pipe 10 has a clamping part 106, and the outer circumferential side wall of the corresponding stator core 3 has a matching clamping groove 31; as shown in some cases, a single heat pipe 10, the lower end of the heat pipe 10 has a clamping groove, and the outer circumferential side wall of the corresponding stator core 3 has a matching clamping part.

[0077] Of course, the cross section of the card slot 31, in some cases, the cross section of the card slot 31 can be a constricted shape, such as a dovetail slot. At this time, the purpose of such design is that the engagement part of the evaporation section 102 of the heat pipe 10 is matched with the shape of the card slot 31 outside the stator core 3. Through the matching of the dovetail slot, the heat pipe 10 can be fixed on the stator core 3 well, and the contact gap between the evaporation section 102 of the heat pipe 10 and the card slot 31 is filled with heat-conducting silica gel, which can reduce the contact thermal resistance between the stator core 3 and the heat pipe 10. For the engagement part 106 of the evaporation section 102 of the heat pipe 10, in this application, the shape of the evaporation section 102 of the heat pipe 10 can be changed, such as being transformed into a dovetail slot matched engagement part.

[0078] It should be noted that the heat pipe 10 is connected to the stator core 3 by the matching of the card slot and the engagement part. Considering that the heat pipe 10 is embedded outside the stator core 3, and the stator core 3 is part of the magnetic circuit of the back-wound winding high-speed permanent magnet motor, in order to reduce the influence on the electromagnetic performance of the back-wound winding high-speed permanent magnet motor, the depth of the card slot 31 should not be too large. At this time, the depth of the card slot 31 should be determined according to the size of the back-wound winding high-speed permanent magnet motor. For example, when the radial length of the stator yoke is 15 mm, the depth of the card slot 31 is preferably between 1 mm and 2 mm. In this embodiment, the depth of the card slot 31 is not strictly limited, and should be reasonably designed on the basis of fixing the heat pipe 10.

[0079] Embodiment two:

[0080] A back-wound winding high-speed permanent magnet motor, comprising the cooling structure of embodiment one, wherein at least one heat pipe 10 is installed on the outer circumferential side wall of the stator core 3 instead of the outer tooth 4 of the stator core 3, and the top end of the cooling structure is attached to the inner wall of the liquid cooling shell 1.

[0081] The liquid cooling shell 1 has a liquid cooling channel inside, and the liquid cooling channel is filled with cooling liquid 2.

[0082] The cooling structure conducts heat on the stator core 3 to the liquid cooling shell 1, and the cooling liquid 2 in the liquid cooling shell 1 dissipates heat.

[0083] At this time, the evaporation section 102 of the heat pipe 10 is in contact with the stator core 3, and the condensation section 101 of the heat pipe 10 is in contact with the liquid cooling shell 1. Due to the extremely strong heat conduction capacity of the heat pipe 10, the heat resistance of the heat transfer from the inside of the back-wound winding high-speed permanent magnet motor to the liquid cooling shell 1 can be effectively reduced, so that the heat concentrated in the stator core 3 and the winding can be quickly transferred to the liquid cooling shell 1 and the heat can be quickly removed by the cooling liquid; and the heat pipe 10 can also quickly transfer the heat of the outer winding in the outer slot 6 in contact with the heat pipe 10 to the liquid cooling shell 1. The combined effect of the two aspects greatly reduces the temperature rise of the back-wound winding high-speed permanent magnet motor; in this stage, when the heat pipe 10 is used to replace part of the outer teeth 4 of the stator core 3, it can play a role in assisting the support of the stator core 3 in structure, and has little effect on the electromagnetic performance.

[0084] Regarding the number of outer teeth 4 of the stator core 3 replaced by the heat pipe 10, in the present application, the maximum number of outer teeth 4 of the stator core 3 replaced by the heat pipe 10 is less than the total number of outer teeth 4 of the stator core 3, that is, at least one outer tooth 4 of the stator core 3 needs to be reserved, because the outer teeth 4 play a role in supporting the stator in structure. When the number of outer teeth 4 of the stator core 3 is reduced, especially when the number of outer teeth is too small, it may cause uneven stress on the stator of the back-wound winding high-speed permanent magnet motor, and further cause the motor to vibrate and other adverse consequences;

[0085] Regarding the layout of the heat pipe 10 replacing the outer teeth 4 of the stator core 3, in the present application, it can randomly replace the outer teeth 4 of the stator core 3 at any position, for example, in some cases, it is assumed that the number of inner slots 7 of the stator core 3 is equal to the number of outer slots 6, as shown in Figure 3 and Figure 4 The number of outer teeth 4 of the stator core 3 is 12, the number of heat pipes 10 is 12, the number of outer teeth 4 of the stator core 3 is the same as the number of inner teeth of the stator core 3, and the number of inner teeth of the stator core 3 is 24; in this diagram, the heat pipes 10 replace the outer teeth 4 of the stator core 3 alternately, the heat pipes 10 and the outer teeth 4 of the stator core 3 form a circumferential space alternately arranged structure, and the heat pipes 10 and the adjacent outer teeth 4 of the stator core 3 form an outer slot 6. By uniformly and widely arranging the heat pipes 10 on the stator core 3, the heat pipe 10 arrangement structure is beneficial to ensure that the heat generated by the stator core 3 of the back-wound winding high-speed permanent magnet motor can be quickly transferred to the heat pipe 10 and then to the liquid cooling shell 1.

[0086] For example, in some cases, it is assumed that the number of inner slots 7 of the stator core 3 is equal to the number of outer slots 6, as shown in Figure 5As shown, the number of outer teeth 4 of the stator core 3 is 6, the number of heat pipes 10 is 18, and the number of inner teeth of the stator core 3 is 24; in this illustration, the heat pipes 10 are distributed in a scattered and concentrated manner, that is, a continuous heat pipe group, every three heat pipes 10 form a group, one heat pipe 10 group replaces three or more adjacent outer teeth 4 of the stator core 3, and the remaining heat pipe 10 groups are uniformly distributed along the circumferential direction of the stator core 3 and replace the adjacent outer teeth 4. At this time, the arrangement structure of the heat pipes 10 is beneficial to further reduce the thermal resistance in the heat transfer process of the stator core and enhance the heat dissipation capacity of the motor.

[0087] Of course, for some cases, the length of the heat pipe 10 along the axial direction of the stator core 3 is set, such as in some cases, such as Figure 6 As shown, the length of the heat pipe 10 is equal to the length of the stator core 3, and the axial end faces of the two sides of the stator core 3 are flush with the end faces of the heat pipe 10. At this time, the processing difficulty of the heat pipe 10 can be reduced, and the installation of the heat pipe 10 is facilitated.

[0088] The liquid cooling shell 1 has a liquid cooling channel, and the liquid cooling channel is filled with cooling liquid 2. According to different use conditions, the cooling liquid is preferably No. 65 cooling liquid, pure water, oil, ethylene glycol, etc., and the liquid cooling channel is preferably "Z" shaped or spiral shaped.

[0089] In order to verify the conclusion that the heat pipe 10 has no effect on the electromagnetic performance of the motor, the inventors compare the electromagnetic performance of the high-speed permanent magnet motor with and without the heat pipe 10. Figure 3 As shown, the heat pipe structure and the electromagnetic performance of the high-speed permanent magnet motor with back-wound windings without using the heat pipe are compared. The electromagnetic performance under no load and load is compared as follows.

[0090] Figures 11-16 The simulation results of the magnetic field lines, magnetic flux density distribution and no-load back electromotive force of the two motors under no load are given. From Figure 11 , 12 It can be seen that the magnetic field lines of the motor after installing the heat pipe 10 are uniformly distributed and have a reasonable trend, which is basically consistent with the magnetic field line distribution trend of the conventional motor without installing the heat pipe 10; from Figure 13 , 14 It can be seen that the magnetic flux density distribution and the magnetic flux density of the motor with and without the heat pipe 10 are highly consistent. From Figure 15 , 16 It can be seen that the effective values of the no-load back electromotive force of the two motors are 151V and 149.8V, respectively, which are basically consistent. Therefore, the installation of the heat pipe 10 has no effect on the no-load electromagnetic performance of the high-speed permanent magnet motor with back-wound windings.

[0091] Figure 17 , 18The electromagnetic torque curves of two motors under load are respectively given, and the drive currents of the motors are all set to 120 A. It can be seen that the average electromagnetic torques of the motors with and without the heat pipes 10 are 17.2539 Nm and 17.1264 Nm respectively, that is, the electromagnetic torques are basically consistent, and the torque fluctuations are also basically consistent. Therefore, replacing part of the stator outer teeth 4 with the heat pipes 10 basically has no effect on the load torque of the motor.

[0092] In summary, the cooling structure of the application basically has no effect on the electromagnetic performance of the back-wound winding high-speed permanent magnet motor.

[0093] In addition, in order to verify the cooling effect of the cooling structure, the temperature field of the motor with the cooling structure as shown in Figures 4-6 is simulated and analyzed based on the thermal analysis software Ansys Fluent, and the temperature field simulation results of the conventional back-wound winding motor without the cooling structure of the application are also given for comparison.

[0094] Figures 19-21 The winding, core and overall temperature field distributions of the conventional back-wound winding motor without the cooling structure of the application are given, Figures 22-24 The winding, core and overall temperature field distributions of the motor with 12 heat pipes and the length of the heat pipes being equal to the length of the core (corresponding to the application Figure 6 ) are given, Figures 25-27 The winding, core and overall temperature field distributions of the motor with 12 heat pipes and the length of the heat pipes being greater than the length of the core (corresponding to the application Figure 4 ) are given, Figures 28-30 The winding, core and overall temperature field distributions of the motor with 18 heat pipes and the length of the heat pipes being greater than the length of the core (corresponding to the application Figure 5 ) are given.

[0095] By comparing the winding 8 temperature distribution diagrams shown in Figure 19 , 22 , 25, 28, it can be seen that the highest temperature of the winding 8 without the heat pipes 10 is 90.9℃; when 12 heat pipes 10 with the same length as the stator core 3 are installed, the highest temperature of the winding obviously decreases to 76.2℃, which is 14.7℃ lower than that without the heat pipes 10; when 12 heat pipes 10 with the length greater than the stator core 3 are installed, the highest temperature of the winding decreases to 72.4℃, which is 3.8℃ lower than that of the cooling structure shown in Figure 6 , which shows that increasing the length of the heat pipes 10 and the contact area with the winding is effective for reducing the temperature of the winding 8; when 18 heat pipes 10 are installed, the highest temperature of the winding 8 decreases to 68.9℃, which is 22℃ lower than that without the heat pipes 10.

[0096] By comparing the winding 8 temperature distribution diagrams shown in Figure 20 ,23 As shown in Figures 26 and 29, the temperature distribution diagrams of the stator core 3 show that the change in the highest temperature of the stator core 3 is basically consistent with the change in the highest temperature of the winding 8. The highest temperature of the stator core 3 without heat pipe 10 is 92.0℃, while the temperature using the corresponding... Figure 6 , 4 The highest temperatures of the stator cores with the cooling structures shown in Figures 1 and 5 are 76.1℃, 74.0℃, and 68.8℃, respectively. The highest temperatures of the stator cores with all three cooling structures decrease by more than 15℃. Figure 5 The cooling structure shown exhibits the largest temperature drop, with the stator core temperature dropping by as much as 21.2℃.

[0097] contrast Figure 21 , 24 The overall temperature distribution diagrams of the motor shown in Figures 27 and 30 show that the highest temperature of the motor occurs on the rotor sheath 13. The highest temperature of the motor without heat pipes is 133.5℃, while the highest temperature of the motor with corresponding heat pipes is 133.5℃. Figure 6 , 4 The highest temperatures of the motors with the cooling structures shown in Figures 1 and 5 are 122.2℃, 121.2℃, and 116.2℃, respectively. The highest temperature of the motors with all three cooling structures decreases by more than 11℃. Figure 5 The maximum temperature drop of the motor in the cooling structure shown is significantly higher than that of the motor. Figure 4 , 6 The two cooling structures shown have a temperature of 17.3℃, indicating that increasing the number of heat pipes 10 can further enhance the heat dissipation capacity of the motor.

[0098] In summary, using heat pipes instead of stator external teeth 4 can significantly reduce the temperature of winding 8, stator core 3 and rotor. Furthermore, by extending the length of heat pipe 10 and increasing the number of heat pipes 10, the temperature rise can be further reduced, verifying that the cooling structure of the present invention can significantly reduce the heating of back-wound motors.

[0099] In summary, for the conventional back-wound high-speed permanent magnet motor with liquid-cooled casing, the heat of the stator core 3 and the winding is firstly transferred to the outer teeth 4 of the stator core 3, and then transferred to the liquid-cooled casing 1 from the stator outer teeth 4. Since the material of the stator outer teeth 4 is silicon steel sheet or other core material, the heat conduction capacity is poor, and the thermal resistance of the heat transfer from the stator to the outside is large, so the back-wound high-speed permanent magnet motor has a serious heating problem. In the structure of the present application, the heat pipe 10 is used to replace part of the stator outer teeth 4 of the back-wound high-speed permanent magnet motor. Since the heat pipe 10 uses the vapor-liquid phase change process of the liquid to conduct heat, the heat conduction capacity is extremely strong, much higher than that of silicon steel sheet or other core material, so it can effectively reduce the thermal resistance of the heat transfer of the internal heat of the back-wound high-speed permanent magnet motor to the liquid-cooled casing 1, and the heat concentrated in the stator core 3 and the winding can be quickly transferred to the liquid-cooled casing 1. The heat pipe 10 can also quickly transfer the heat of the outer winding in the stator outer slot 6 in close contact with it to the liquid-cooled casing 1. The combined effect of the two can quickly transfer the heat in the stator core 3 and the winding to the liquid-cooled casing 1, which is quickly taken away by the cooling liquid, thereby greatly reducing the temperature rise of the back-wound high-speed permanent magnet motor. The heat pipe 10 of the present embodiment plays a role in supporting the stator in structure, and has little effect on electromagnetic performance.

[0100] It is to be understood that the terms "including", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0101] For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. When an element is referred to as "assembled", "mounted", "fixed" or "disposed" on another element, it can be directly on the other element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0102] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

[0103] In the description of the disclosure, the description of the terms "one embodiment", "an example", "a specific example" and the like is intended to mean that the specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the disclosure. In the description of the disclosure, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or several embodiments or examples in a suitable manner.

Claims

1. A cooling structure of a back-wound winding high-speed permanent magnet motor, characterized in that, comprising: a heat pipe (10) which is shaped in imitation of the outer tooth (4) of the stator core (3) of the back-wound winding high-speed permanent magnet motor, when at least one heat pipe (10) replaces the outer tooth (4) of the stator core (3) and is installed on the outer circumferential side wall of the stator core (3): if the heat pipe (10) is one, the heat pipe (10) and the adjacent outer tooth (4) of the stator core (3) form an outer slot (6); if the heat pipe (10) is more than one, when the heat pipe (10) is adjacent to another heat pipe (10), the heat pipe (10) and the adjacent another heat pipe (10) form an outer slot (6); and, at least one heat pipe (10) is adjacent to the outer tooth (4) of the stator core (3), the heat pipe (10) and the adjacent outer tooth (4) of the stator core (3) form an outer slot (6); wherein the condensation section of the heat pipe (10) exchanges heat with the liquid cooling shell (1) of the back-wound winding high-speed permanent magnet motor.

2. The cooling structure of a high-speed permanent-magnet motor with a back-wound winding according to claim 1, characterized in that, The heat pipe (10) and the outer circumferential side wall of the stator core (3) are detachably fixedly connected.

3. The cooling structure of a high-speed permanent-magnet motor with a back-wound winding according to claim 2, characterized in that, The lower end of the heat pipe (10) has a clamping part or a clamping groove, and the corresponding outer circumferential side wall of the stator core (3) has a matching clamping groove or clamping part; the heat pipe (10) and the outer circumferential side wall of the stator core (3) are connected by the matching of the clamping groove and the clamping part.

4. The cooling structure of a high-speed permanent-magnet motor with a back-wound winding according to claim 3, characterized in that, The gap between the clamping part and the clamping groove is filled with heat-conducting silicone.

5. The cooling structure of a high-speed permanent-magnet motor with a back-wound winding according to claim 1, characterized in that, The length of the heat pipe (10) is equal to the length of the stator core (3), and the axial end faces of the two sides of the stator core (3) are flush with the end faces of the heat pipe (10).

6. The cooling structure of a high-speed permanent-magnet motor with a back-wound winding according to claim 1, characterized in that, The length of the heat pipe (10) is greater than the length of the stator core (3), and the heat pipe (10) exceeding the axial end faces of the two sides of the stator core (3) forms a half-enclosing structure to the end (9) of the back-wound winding (8).

7. The cooling structure of a high-speed permanent-magnet motor with a back-wound winding according to claim 1, characterized in that: The outer side wall of the condensation section of the heat pipe (10) forms a circular arc surface which is matched with the inner wall of the liquid cooling shell (1).

8. A high speed permanent magnet machine with a back-wound winding, characterized in that, comprising the cooling structure of any one of claims 1-7, when at least one heat pipe (10) replaces the outer tooth (4) of the stator core (3) and is installed on the outer circumferential side wall of the stator core (3), the top end of the cooling structure is matched with the inner wall of the liquid cooling shell (1); the liquid cooling shell (1) has a liquid cooling channel inside, and the liquid cooling channel is filled with cooling liquid (2); the cooling structure conducts heat from the stator core (3) and the back-wound winding (8) to the cooling liquid in the liquid cooling shell (1), and the cooling liquid dissipates heat.

9. The back-wound high-speed permanent-magnet electric machine of claim 8, wherein, The heat pipe (10) and the outer tooth (4) of the stator core (3) form a circumferential space alternating arrangement structure.

10. The back-wound high-speed permanent-magnet electric machine of claim 9, wherein, A plurality of heat pipes (10) form a group to replace a corresponding number of outer teeth (4) of a plurality of adjacent stator cores (3).

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