CN201656595U - Stator cooling system of high-speed permanent magnet motor - Google Patents

Abstract

The utility model relates to a stator cooling system of a high-speed permanent magnet motor, belonging to the technical field of a motor and solving the problem that the working stability of a permanent magnet in the motor and the whole motor is reduced as the rotor temperature of the existing high-speed permanent magnet motor is over high. The stator cooling system of the high-speed permanent magnet motor comprises a machine shell and a stator core, wherein the stator core is covered in the machine shell. The inner periphery of the stator core is uniformly distributed with a plurality of stator slots along a periphery direction in a radial mode, and windings are wound in the stator slots of the stator core. The slot port of each stator slot is provided with a stator slot wedge which is closely matched with the inner wall of the slot port of the stator slot, and an inner cooling pipeline is arranged in an axial channel formed by each stator slot wedge, two side walls of the stator slot and the inner surface and the outer surface of the slot of the winding. Two end parts of a plurality of inner cooling pipelines are respectively collected together to form an inlet and an outlet. The stator cooling system of the high-speed permanent magnet motor is used for cooling the high-speed permanent magnet motor.

Description

High speed permanent magnet motor stator cooling system

technical field

The utility model relates to a high-speed permanent magnet motor stator cooling system, which belongs to the technical field of motors.

Background technique

High-speed permanent magnet motor not only has the characteristics of high speed, high power density, high material utilization rate, fast dynamic response and high efficiency of transmission system of ordinary high-speed motors, but also has the advantages of high efficiency and high power factor, so it is used in air conditioners or Centrifugal compressors for refrigerators, energy storage flywheels, textiles, high-speed grinders, hybrid vehicles, aviation, ships and other fields have good application prospects. Especially in the distributed power generation system, due to the small size and high mobility of the high-speed permanent magnet motor driven by the gas turbine, it can be used as a backup power source for hospitals, hotels and other important facilities, and can also be used as an independent power source or small power station , to make up for the lack of centralized power supply, which has important practical value.

When the high-speed permanent magnet motor is running, the current frequency of the stator winding is as high as 1000Hz, and the rotation speed of the rotor is as high as tens of thousands of revolutions per minute. The motor core has a high power density. It consumes a lot. In this type of motor, the heat dissipation is generally carried out by passing the cooling medium in the closed cavity on the stator side or by opening the ventilation. Considering the structure and safety of the cooling system, the generally used insulating cooling medium has poor thermal conductivity and cooling The effect is not strong, especially the heat dissipation effect on the rotor is small, so that the inner rotor of the motor will still have a high temperature rise, and the temperature of the rotor is too high, which will affect the permanent magnet in the motor and the working stability of the entire motor. At the same time shorten its service life.

Contents of the invention

The utility model provides a high-speed permanent magnet motor stator cooling system in order to solve the problem that the rotor temperature of the existing high-speed permanent magnet motor is too high, which reduces the working stability of the permanent magnet in the motor and the entire motor.

The utility model comprises a casing and a stator core, the stator core is covered in the casing, a plurality of stator slots are uniformly distributed radially along the circumferential direction on the inner circumference of the stator core, windings are wound in the stator slots of the stator core, each A stator wedge is arranged at the notch of the stator slot, and the stator wedge closely matches the inner wall of the notch of the stator slot. Each stator wedge is formed by the two side walls of the stator slot where it is located and the inner and outer surfaces of the winding. Inner cooling pipes are arranged in the axial channel of the inner cooling pipes, and the two ends of the plurality of inner cooling pipes are collected together to form an inlet and an outlet.

The utility model has the advantages that: the utility model is applied to a high-speed motor. When the motor is working, the cooling medium is passed into the inner cooling pipe, and the heat on the stator core will be taken away in time as the cooling medium flows along the axial direction. This in turn cools the stator core. It cancels the airtight plate in the existing motor, increases the length of the air gap in the motor, increases the space for air flow, and enhances the heat conduction effect. The utility model can increase the air gap length of the existing motor from 1 mm to 3 mm, and when the motor speed is 60,000 rpm, the effective thermal conductivity of the air can be increased from 0.28 W/(m*℃) in the existing motor To 0.39 W/(m*℃), which greatly improves the heat conduction capacity of the moving air, so that more heat from the rotor side is transferred to the stator side.

The inner cooling pipeline added in the utility model can avoid the direct contact between the cooling medium and the stator winding iron core and other motor components, so that the motor can be cooled by water and other medium with good cooling performance. Calculation analysis shows that at the same fluid flow rate, when oil cooling is used, the technical solution of the utility model can reduce the maximum temperature rise of the motor by 10°C; when water cooling is used, the temperature change of the motor is more significant. The heat dissipation coefficient of the contact surface is as high as 953W/(m*℃), which can reduce the temperature of the rotor side by about 40℃, effectively avoiding the demagnetization of the permanent magnet inside the motor caused by the excessive temperature rise of the rotor, and greatly improving the stability of the overall working performance of the motor improve.

Description of drawings

Fig. 1 is a structural schematic diagram of the present utility model, and the arrow indicates the flow direction of the cooling medium in the cooling passage; Fig. 2 is a sectional view of AA of Fig. 1; Fig. 3 is a structural schematic diagram of the third embodiment of the present utility model, and the arrow indicates cooling The flow direction of the cooling medium in the channel; Fig. 4 is a BB sectional view of Fig. 3; Fig. 5 is a schematic diagram of the inner diameter of the cooling pipeline described in Embodiment 1, 2, 3 or 4; Fig. 6 is a schematic diagram of the cooling pipeline described in Embodiment 5 Fig. 7 is a schematic diagram of the change of the inner diameter of the cooling pipeline described in Embodiment 6; Fig. 8 is a schematic diagram of the variation of the inner diameter of the cooling pipeline described in Embodiment 8, and h represents the cooling pipeline in Fig. 5 to Fig. 8 The inner diameter of the tube, L represents the length of the cooling pipe; Fig. 9 is a graph showing the change in the heat dissipation coefficient of the cooling medium in Embodiment 1; Fig. 10 is a graph showing the change in the heat dissipation coefficient of the cooling medium in Embodiment 5; Fig. 11 is a graph showing the change in the heat dissipation coefficient of the cooling medium in Embodiment 6 Fig. 12 is a graph showing the change of cooling medium heat dissipation coefficient; Fig. 12 is a graph showing the change of cooling medium heat dissipation coefficient in Embodiment 8; Fig. 13 is a graph showing the temperature change curve of the motor axial stator winding when the inner diameter of the cooling pipe adopts different technical solutions. Curve A is the temperature change curve of the stator winding in Embodiment 1, curve B is the temperature change curve of the stator winding in Embodiment 5, curve C is the temperature change curve of the stator winding in Embodiment 6, and curve D is the temperature change of the stator winding in Embodiment 8 Curve; Fig. 14 is the temperature change curve of the axial rotor of the motor when the pipe inner diameter of the cooling pipe adopts different technical solutions, and the curve E in the figure is the rotor temperature change curve in the first embodiment, F is the rotor temperature change curve in the eighth embodiment, G is the temperature change curve of the rotor in Embodiment 6, and H is the temperature change curve of the rotor in Embodiment 5.

Detailed ways

Embodiment 1: The present embodiment will be described below in conjunction with FIGS. 1 to 5. This embodiment includes a casing 1 and a stator core 2. The stator core 2 is housed in the casing 1. The inner circumference of the stator core 2 is along the circumference. A plurality of stator slots 2-1 are uniformly distributed radially in the direction, windings 2-2 are wound in the stator slots 2-1 of the stator core 2, and a stator slot wedge 2-3 is arranged at the notch of each stator slot 2-1, The stator wedge 2-3 is closely matched with the inner wall of the notch of the stator slot 2-1, and each stator wedge 2-3 is connected with the two side walls of the stator slot 2-1 and the inside and outside of the winding 2-2. Internal cooling pipes 2-4 are arranged in the axial channel formed on the surface, and the two ends of the plurality of internal cooling pipes 2-4 are collected together to form an inlet 2-5 and an outlet 2-6.

In this embodiment, the winding 2-2 is wound in the stator slot 2-1 of the stator core 2. In order to pass the cooling medium, the winding 2-2 only occupies a part of the space of the stator slot 2-1, and the remaining part is used for internal cooling. Pipeline 2-4. The inner cooling pipeline 2-4 is made of non-conductive, high thermal conductivity material.

In the stator cooling system of the existing motor, an oil separator is usually designed to isolate the cooling medium from the stator and rotor, and the cooling medium is in direct contact with the stator winding core and other motor components, so an insulating cooling medium, such as transformer oil, is required. The oil separator is made of polyimide film, and its thermal conductivity is <1 W/(m*℃), generally 0.3 W/(m*℃). Considering the high-speed rotation of the air, the fluid in the air gap is in a state of high turbulence. After analysis, the thermal conductivity of the air only reaches 0.28 W/(m*℃) (generally, the thermal conductivity of still air is 0.02 W/(m*℃)). The oil separator ring also causes the air gap length of the motor to be too small, which is not conducive to utilizing the thermal conductivity of the air to transfer the heat on the rotor side. In this embodiment, the inner cooling pipe 2-4 is added after the oil separator is removed, which increases the airtightness of the cooling medium inside the motor, and the medium is not in contact with the windings, etc. Therefore, water, freon and other cooling mediums with good cooling performance can be used. The cooling effect of water and freon is much higher than that of transformer oil, and its high thermal conductivity can cool the motor more effectively. Taking water as an example, due to the high thermal conductivity and low kinematic viscosity of water, when its flow rate is 1m/s, the heat dissipation coefficient of the contact surface with the stator of the motor reaches 953W/(m*℃), while in the prior art When the oil is cooled, the heat dissipation coefficient is only 230 W/(m*°C), so the technical solution of the present invention will greatly improve the cooling effect of the motor, reduce the temperature rise of the rotor side by about 40°C, and reduce the temperature rise of the stator armature winding by about 30°C. ℃.

Specific Embodiment 2: The present embodiment will be described below in conjunction with FIG. 3 and FIG. 4 . The difference between this embodiment and Embodiment 1 is that it also includes an outer cooling pipeline row 3 , and the outer cooling pipeline row 3 is arranged on the casing 1 and the outer surface of the stator core 2. Other components and connections are the same as those in Embodiment 1.

The outer cooling pipeline row 3 can directly cool the motor yoke, which can further reduce the temperature of the motor.

Embodiment 3: The difference between this embodiment and Embodiment 2 is that the input port of the cooling pipe row 3 communicates with the inlet 2-5 of the inner cooling pipe 2-4, and the output port of the cooling pipe row 3 It communicates with the outlet 2-6 of the internal cooling pipeline 2-4. Other components and connections are the same as those in Embodiment 2.

The outer cooling pipe row 3 and the ends of the inner cooling pipes 2-4 are collected together with a busbar to form an overall circulating cooling system. On the one hand, the auxiliary power equipment of the cooling system and the connection equipment of the cooling pipes inside the motor are reduced. The airtight reliability of the cooling system is improved; on the other hand, the length of the outer cooling pipe row 3 and the inner cooling pipe 2-4 inside the motor is partially increased, which can play a more effective role in cooling, especially for the end of the stator winding. The effect is more significant.

Specific Embodiment 4: This embodiment will be described below in conjunction with Fig. 3 and Fig. 4. The difference between this embodiment and Embodiment 2 or 3 is that each pipe in the outer cooling pipe row 3 is connected between the casing 1 and the stator core. The outer circular surfaces of 2 are adjacently arranged along the axial direction. Other compositions and connections are the same as those in the second or third embodiment.

In this embodiment, the temperature of the stator core 2 of the motor can be reduced by 30° C. under the joint action of the outer cooling pipe row 3 and the inner cooling pipes 2-4. At the same time, due to the reduction of the stator temperature, more heat from the rotor can be transferred to the stator. Analysis shows that, compared with the technical solution of Embodiment 1, this embodiment can further reduce the temperature of the rotor side by 10°C. The reduction of the working temperature on the rotor side can make the working performance of the permanent magnets more stable and prolong the life of the motor.

Embodiment 5: The difference between this embodiment and Embodiment 4 is that each pipe in the inner cooling pipe 2-4 and the outer cooling pipe row 3 is divided into two sections along the axial direction, that is, the inlet section and the The outlet section, the inner diameter of the outlet section is half of the inner diameter of the inlet section. Other components and connections are the same as those in Embodiment 4.

Embodiment 6: The difference between this embodiment and Embodiment 4 is that each pipe in the inner cooling pipe 2-4 and the outer cooling pipe row 3 is divided into three sections along the axial direction, that is, the inlet section, For the middle section and the outlet section, the inner diameter of the middle section is three-quarters of the inner diameter of the inlet section, and the inner diameter of the outlet section is one-half of the inner diameter of the inlet section. Other components and connections are the same as those in Embodiment 4.

Embodiment 7: This embodiment differs from Embodiment 4 in that the inner diameter of each pipe in the inner cooling pipe 2 - 4 and the outer cooling pipe row 3 decreases linearly along the axial direction. Other components and connections are the same as those in Embodiment 4.

Embodiment 8: The difference between this embodiment and Embodiment 7 is that the inner diameter of the outlet of the inner cooling pipeline 2-4 and the outer cooling pipeline row 3 is half of the inner diameter of the inlet. Other components and connections are the same as those in Embodiment 7.

Combining the above embodiments with FIGS. 5 to 14 , it can be seen that at the position where the cross-sectional area of the cooling pipe changes, the heat dissipation coefficient of the fluid changes abruptly, and the distribution curve of the heat dissipation coefficient appears an inflection point. In the case of keeping the flow rate of the cooling medium constant, as the cross-sectional area where the fluid passes decreases, the heat dissipation coefficient of the cooling medium increases accordingly.

When cooling pipes with variable diameters are used, the temperature at different positions in the motor decreases to varying degrees, as shown in Table 1, where the average temperature drops of the stator core and rotor body reach 15°C and 12°C, respectively. At the same time, the axial temperature difference of different positions of the motor is reduced, the axial temperature difference of the stator winding is reduced by 43%, the axial temperature difference of the rotor is reduced by 44%, the axial temperature difference of the stator core position is reduced by 29%, and the temperature distribution in the motor tends to be uniform.

It can be seen that through reasonable design, reducing the diameter of the cooling pipe at different positions in the axial direction of the cooling pipe can effectively increase the heat dissipation capacity of the cooling medium and make the temperature distribution in the motor tend to in uniform.

Embodiment 9: The difference between this embodiment and Embodiment 2 or 3 is that the outer cooling pipe row 3 is circular, and each pipe in the outer cooling pipe row 3 is between the casing 1 and the stator core 2 The outer circular surfaces are adjacently arranged along the circumferential direction. Other compositions and connections are the same as those in the second or third embodiment.

This embodiment can effectively increase the length of the outer cooling pipe row 3 inside the motor, thereby enhancing the heat dissipation effect of the cooling medium; at the same time, the outer cooling pipe row 3 and the inner cooling pipes 2-4 distributed in the circumferential direction form a grid cross cooling layout , can make the motor stator temperature distribution more uniform.

Claims (9)

1. A high-speed permanent magnet motor stator cooling system, which includes a casing (1) and a stator core (2), the stator core (2) is covered in the casing (1), and the inner circumference of the stator core (2) A plurality of stator slots (2-1) are evenly distributed radially along the circumferential direction, and the windings (2-2) are wound in the stator slots (2-1) of the stator core (2), which is characterized in that: each stator slot ( A stator wedge (2-3) is set at the notch of 2-1), and the stator wedge (2-3) is closely matched with the inner wall of the notch of the stator slot (2-1), and each stator wedge (2-3) The internal cooling pipeline (2-4) is set in the axial channel formed by the two side walls of the stator slot (2-1) where it is located and the inner and outer surfaces of the slot of the winding (2-2). The two ends of the internal cooling pipes (2-4) are brought together to form an inlet (2-5) and an outlet (2-6). 2. The high-speed permanent magnet motor stator cooling system according to claim 1, characterized in that it also includes an outer cooling pipeline row (3), and the outer cooling pipeline row (3) is arranged between the casing (1) and the stator Between the outer circular surfaces of the iron core (2). 3. The high-speed permanent magnet motor stator cooling system according to claim 2, characterized in that: the input port of the cooling pipeline row (3) communicates with the inlet (2-5) of the inner cooling pipeline (2-4) , the outlet of the cooling pipeline row (3) communicates with the outlet (2-6) of the inner cooling pipeline (2-4). 4. The high-speed permanent magnet motor stator cooling system according to claim 2 or 3, characterized in that: each pipe in the outer cooling pipe row (3) is between the casing (1) and the stator core (2) The outer circular surfaces are adjacently arranged along the axial direction. 5. The high-speed permanent magnet motor stator cooling system according to claim 4, characterized in that: each of the inner cooling pipes (2-4) and the outer cooling pipe row (3) is equally divided along the axial direction It is two sections, that is, an inlet section and an outlet section, and the inner diameter of the outlet section is 1/2 of the inner diameter of the inlet section. 6. The high-speed permanent magnet motor stator cooling system according to claim 4, characterized in that: each pipe in the inner cooling pipe (2-4) and the outer cooling pipe row (3) is equally divided along the axial direction It is three sections, namely the inlet section, the middle section and the outlet section. The inner diameter of the middle section is three-quarters of the inner diameter of the inlet section, and the inner diameter of the outlet section is one-half of the inner diameter of the inlet section. 7. The high-speed permanent magnet motor stator cooling system according to claim 4, characterized in that: each pipe in the inner cooling pipe (2-4) and the outer cooling pipe row (3) is in the pipe along the axial direction The diameter shrinks linearly. 8. The high-speed permanent magnet motor stator cooling system according to claim 7, characterized in that: the inner diameter of the inner cooling pipe (2-4) and the outlet of the outer cooling pipe row (3) is equal to the inner diameter of the inlet pipe Half. 9. The high-speed permanent magnet motor stator cooling system according to claim 2 or 3, characterized in that: the outer cooling pipe row (3) is circular, and each pipe in the outer cooling pipe row (3) is The casing (1) and the outer circular surface of the stator core (2) are adjacently arranged along the circumferential direction.

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