A micro heat pipe array-casing water cooling combined cooling structure of a permanent magnet motor

Abstract

The application discloses a kind of permanent magnet motor micro heat pipe array-casing water cooling composite cooling structure, and permanent magnet motor includes casing and stator winding, and spiral water channel is opened in casing wall, and micro heat pipe array is equipped in casing, and micro heat pipe array and stator winding end portion are contacted;The permanent magnet motor micro heat pipe array-casing water cooling composite cooling structure of the application, by directly arranging micro heat pipe array in winding end portion surface, increase the contact area of heat source and micro heat pipe, can more effectively take away the heat generated by winding, to significantly improve winding cooling efficiency;Condensing section of micro heat pipe array is inserted into casing, and circulating water in casing spiral water channel is accelerated to cool the cooling medium in micro heat pipe, realize the gas-liquid rapid circulation of cooling medium (deionized water) in micro heat pipe, and casing spiral water channel is cooled to motor stator, to further improve the heat dissipation effect of permanent magnet motor.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet motor cooling technology, and in particular to a permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure. Background Technology

[0002] In recent years, permanent magnet motors have been widely used in fields with strict weight and space requirements, such as electric vehicles, ship propulsion, and aerospace, due to their high efficiency and excellent electromagnetic performance. With increasing demands for motor winding current density and overall power density, motor structures have become more compact, leading to a rapid increase in temperature rise at the motor winding ends and increased difficulty in heat dissipation. Excessive temperature rise will seriously affect the reliability of motor operation; therefore, designing an efficient cooling system is crucial for the long-term stable operation of the motor.

[0003] In existing motor cooling structures, liquid cooling media such as water and oil have a higher specific heat capacity than air, resulting in better cooling performance than air cooling. However, water cooling cannot directly cool the ends of the motor windings, failing to effectively suppress temperature rise during motor operation. Heat pipe cooling technology, compared to other cooling methods, offers advantages such as high thermal conductivity, compact structure, and the ability to withstand complex environments, and is increasingly being applied to motor cooling systems.

[0004] Existing motor cooling structures often suffer from uneven cooling and difficulty in localized heat dissipation. Therefore, designing a motor cooling system with high cooling efficiency is crucial to ensuring the long-term stable operation of the motor. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a micro heat pipe array-casing water-cooled composite cooling structure for permanent magnet motors, which aims to solve the problem that existing motors using water cooling methods cannot directly cool the ends of the motor windings, and cannot effectively suppress the temperature rise of the windings during motor operation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure is disclosed. The permanent magnet motor includes a casing, an end cover and a rotating shaft. The rotating shaft is arranged radially with a rotor core, a permanent magnet, a stator winding and a stator core. The end of the casing is connected to the rotating shaft through a bearing. A spiral water channel is opened in the casing wall. A micro heat pipe array is arranged in the casing and is in contact with the end of the stator winding.

[0007] Furthermore, the inner wall of the housing is provided with multiple insertion holes spaced apart circumferentially, and the positions of the insertion holes correspond to the stator windings.

[0008] Furthermore, the micro heat pipe array consists of multiple micro heat pipes, each including a condensation section and an evaporation section.

[0009] Furthermore, the condensing section and the evaporating section are connected in an L-shape, and the included angle between the condensing section and the evaporating section is 60° to 90°.

[0010] Furthermore, the micro heat pipe uses an aluminum heat pipe with an internal groove structure without a liquid wick. It relies on the sharp corners and narrow slits of the inner wall of the groove to generate capillary force, forming a capillary barrier. The cross-section of the cooling medium microchannel of the single-channel coreless micro heat pipe is approximately trapezoidal, and multiple microchannels are arranged in parallel.

[0011] Furthermore, the evaporation section is flat and is connected to the stator winding end by adhesive bonding.

[0012] Furthermore, the micro heat pipe condensation section is inserted into the inner wall of the casing through a socket.

[0013] Furthermore, the gap between the evaporation section and the end of the stator winding is filled with a silicone thermal pad.

[0014] Furthermore, the spiral waterway has an inlet and an outlet at each end, both of which extend outside the casing.

[0015] The technical solution adopted in this invention has the following beneficial effects: Compared with existing technologies, the permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure of the present invention increases the contact area between the heat source and the micro heat pipes by directly arranging the micro heat pipe array on the end surface of the winding, which can more effectively remove the heat generated by the winding and thus significantly improve the winding cooling efficiency. The condensation section of the micro heat pipe array is inserted into the casing, and the circulating water in the spiral water channel of the casing accelerates the cooling of the cooling medium in the micro heat pipe, realizing the rapid gas-liquid circulation of the cooling medium (deionized water) in the heat pipe. At the same time, the spiral water channel of the casing cools the motor stator, further improving the heat dissipation effect of the permanent magnet motor. Attached Figure Description

[0016] Figure 1 A schematic diagram of the axial cross-sectional structure of the motor cooling system; Figure 2 A schematic diagram of the radial cross-sectional structure of the motor cooling system; Figure 3 This is a schematic diagram of a micro heat pipe. Figure 4 This is a diagram of the overall structure of a micro heat pipe. Figure 5 This is a diagram of the internal structure of a micro heat pipe. Figure 6 A schematic diagram of the axial cross-sectional structure of the housing opening; Figure 7 A comparison diagram of the winding temperature rise of the water-cooled casing (left) and the composite cooling structure (right).

[0017] 1. Housing, 2. Spiral water channel, 3. End cover, 4. Stator core, 5. Stator winding, 6. Rotor core, 7. Permanent magnet, 8. Shaft, 9. Bearing, 10. Condensation section, 11. Evaporation section, 12. Insertion hole, 13. Water inlet, 14. Water outlet, 15. Microchannel, 16. Capillary barrier. Detailed Implementation

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] A permanent magnet motor micro heat pipe array-housing housing 1 water-cooled composite cooling structure is disclosed. The permanent magnet motor includes a housing 1, an end cover 3 and a rotating shaft 8. The rotating shaft 8 is provided radially with a rotor core 6, a permanent magnet 7, a stator winding 5 and a stator core 4. The end of the housing 1 is connected to the rotating shaft 8 through a bearing 9. A spiral water channel 2 is opened in the wall of the housing 1. A micro heat pipe array is provided inside the housing 1, and the micro heat pipe array is in contact with the end of the stator winding 5.

[0020] In this embodiment, as Figure 1 , Figure 2 , Figure 4 and Figure 6 As shown, multiple insertion holes 12 are spaced apart circumferentially on the inner wall of the housing 1. The positions of the insertion holes 12 correspond to the stator windings 5. The micro heat pipe array is inserted into the inner wall of the housing 1 through the multiple insertion holes 12. The micro heat pipe array is composed of multiple micro heat pipes, each including a condensing section 10 and an evaporating section 11. The condensing section 10 is inserted into the insertion hole 12. The evaporating section 11 is flat and is connected to the end of the stator windings 5 ​​by adhesive bonding. The condensing section 10 and the evaporating section 11 are connected in an L-shape, and the included angle between the condensing section 10 and the evaporating section 11 is 60° to 90°. The gap between the evaporating section 11 and the end of the stator windings 5 ​​is filled with a silicone thermal pad.

[0021] Combination Figure 3 The evaporation section 11 of the micro heat pipe absorbs the heat emitted by the stator winding 5, and the internal coolant phase turns into vapor, which flows to the condensation section 10 and condenses into liquid. At the same time, the condensation section 10 comes into contact with the spiral water channel 2 inside the casing 1, which accelerates the condensation effect.

[0022] The number of micro heat pipe arrays matches the number of slots in the motor, and their dimensions should be close to the width of the motor slots. After bonding the micro heat pipe array to the surface of the winding's extended end, the winding and the evaporation section 11 of the micro heat pipe array are bundled together to ensure the stability of the heat pipe array's arrangement in the motor. The angle between the evaporation section 11 and the condensation section 10 of the micro heat pipe array should be between 60° and 90° to ensure stable and efficient backflow of coolant between the evaporation section 11 and the condensation section 10, enabling coolant backflow within the heat pipes under gravity or against gravity. A silicone thermal pad is filled in the gap between the evaporation section 11 and the winding end to improve the heat pipe's ability to absorb heat from the heat source.

[0023] like Figure 6 As shown, a rectangular insertion hole 12 with a cross-sectional size close to that of the micro heat pipe condensing section 10 is provided circumferentially on the inner surface of the housing 1. The heat pipe condensing section 10 is inserted into the insertion hole 12 of the housing 1, so that the spiral water channel 2 can also cool the micro heat pipe array, accelerate the phase change inside the micro heat pipe array, and realize the rapid gas-liquid circulation of the deionized water cooling medium inside the heat pipe.

[0024] In this embodiment, the micro heat pipe is an aluminum heat pipe, such as... Figure 5 As shown, the interior is a groove structure without a liquid wick. The capillary force is generated by the sharp corners and narrow slits of the inner wall of the groove, forming a capillary barrier 16. The cross-section of the cooling medium microchannel 15 of the single-channel coreless micro heat pipe is approximately trapezoidal, and multiple microchannels 15 are arranged in parallel.

[0025] In this embodiment, as Figure 1 As shown, the spiral water channel 2 is provided with an inlet 13 and an outlet 14 at both ends. Both the inlet 13 and the outlet 14 extend to the outside of the casing 1. The cooling medium in the water channel is water. The inlet 13 is connected to a water pump to realize the circulation of cooling water in the spiral water channel 2 and discharge it through the outlet 14.

[0026] In this invention, the cooling medium within the micro heat pipe array is cooled by cooling water in the water jacket, eliminating the need for an additional cooling system around the heat pipe condensation section 10. This improves the overall cooling effect of the motor while reducing the maintenance and cost issues associated with complex cooling systems. By arranging the micro heat pipe array at the winding end to directly remove the heat generated at the winding end, the temperature at the winding end is reduced more effectively compared to other non-direct contact cooling methods, thus improving the motor's heat dissipation efficiency.

[0027] The working principle of the micro heat pipe is as follows: when the evaporation section 11 is heated, the liquid medium in the channel will evaporate, absorb the heat generated by the heat source, and diffuse to the condensation section 10 under pressure. When the gaseous medium reaches the condensation section 10, it releases heat and becomes liquid under the action of the external cooling environment. Under the action of gravity, the liquid medium returns to the evaporation section 11 through the adiabatic section to complete the heat transfer inside the motor.

[0028] According to the law of thermal conduction, the amount of heat transferred through thermal conduction is: ; ; In the formula, Thermal conductivity; , The temperatures of the two sides of the solid; Thermal conductivity; The thermal conductivity distance for heat transfer; A The thermally conductive area for heat transfer; Q This refers to the heat transferred through the thermally conductive area.

[0029] According to Newton's law of heat dissipation, the heat carried away by convection is: ; In the formula, Q Heat dissipated through convection; h The convective heat dissipation coefficient; A The contact area between the solid and the fluid; The temperature of the solid; The temperature of the fluid.

[0030] To verify the cooling effect of the micro heat pipe-casing 1 water-cooling hybrid cooling structure proposed in this patent on the windings, a comparative analysis was conducted on the winding temperature rise of a permanent magnet motor using only casing 1 water cooling and a permanent magnet motor using the micro heat pipe-casing 1 water-cooling hybrid cooling structure. Under the premise of ensuring consistent operating conditions, ambient temperature, and other conditions, the finite element method was used to simulate and calculate the temperature rise of the windings of the two motors. The simulation results are as follows: Figure 7 As shown in the simulation results, the highest temperature rise of the motor winding using only the water-cooled housing 1 is 64.1K, while the highest temperature rise of the motor winding using the micro heat pipe-housing housing 1 water-cooled hybrid cooling structure is 58.4K. Compared with the single cooling method, the highest temperature rise of the winding is reduced by 5.7K.

Claims

1. A micro heat pipe array-casing water-cooled composite cooling structure for a permanent magnet motor, the permanent magnet motor comprising a casing (1), an end cover (3), and a rotating shaft (8), wherein a rotor core (6), a permanent magnet (7), a stator winding (5), and a stator core (4) are arranged radially on the rotating shaft (8), and the end of the casing (1) is connected to the rotating shaft (8) via a bearing (9), characterized in that, A spiral water channel (2) is provided inside the casing (1), and a micro heat pipe array is provided inside the casing (1), and the micro heat pipe array is in contact with the end of the stator winding (5).

2. The permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure according to claim 1, characterized in that, The inner wall of the housing (1) is provided with multiple insertion holes (12) spaced apart in the circumferential direction, and the position of the insertion holes (12) corresponds to the stator winding (5).

3. The permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure according to claim 2, characterized in that, The micro heat pipe array consists of multiple micro heat pipes, including a condensation section (10) and an evaporation section (11).

4. The permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure according to claim 3, characterized in that, The condensing section (10) and the evaporating section (11) are connected in an L-shape, and the angle between the condensing section (10) and the evaporating section (11) is 60° to 90°.

5. The permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure according to claim 3, characterized in that, The micro heat pipe uses an aluminum heat pipe with an internal groove structure without a liquid wick. It relies on the sharp corners and narrow slits of the inner wall of the groove to generate capillary force and form a capillary barrier (16). The cross-section of the cooling medium microchannel (15) of the single-channel coreless micro heat pipe is approximately trapezoidal, and multiple microchannels (15) are arranged in parallel.

6. The permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure according to claim 3, characterized in that, The evaporation section (11) is flat and is connected to the end of the stator winding (5) by adhesive binding.

7. The permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure according to claim 3, characterized in that, The micro heat pipe condenser section (10) is inserted into the inner wall of the housing (1) through the insertion hole (12).

8. The permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure according to claim 3, characterized in that, The gap between the evaporation section (11) and the end of the stator winding (5) is filled with a silicone thermal pad.

9. The permanent magnet motor micro heat pipe array-casing water-cooled composite cooling structure according to claim 1, characterized in that, The spiral waterway (2) has an inlet (13) and an outlet (14) at both ends, and both the inlet (13) and the outlet (14) extend to the outside of the casing (1).

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