A method for improving the cooling effect of the stator of a high-altitude long-core permanent magnet direct-drive wind turbine

Abstract

The present invention discloses a method for improving the cooling effect of the stator of a long-core permanent magnet direct-drive wind turbine at high altitude, which relates to the technical field of ventilation and cooling of permanent magnet direct-drive wind turbines. The cooling air cools the non-driving end of the stator coil in the annular space; the cooling air is divided into two paths, one path of cooling air flows from a first air inlet cavity to a radial ventilation channel on the corresponding stator core, enters the air gap, and then flows from the air gap to a first air outlet cavity corresponding to the radial ventilation channel on the stator core, enters the first air outlet cavity, and then flows to the second space; the other path of cooling air flows from the first space to the fourth space to cool the driving end of the stator coil, flows from the second air inlet cavity to the radial ventilation channel on the corresponding stator core, enters the air gap, and then flows from the air gap to the second air outlet cavity corresponding to the radial ventilation channel on the stator core, enters the second air outlet cavity, and flows to the third space to the second space. The cooling air flow path of the present invention enables each section of the stator core to obtain more sufficient cooling air, and the cooling effect is significant.

Description

Technical Field

[0001] The present invention relates to the technical field of ventilation and cooling of permanent magnet direct-drive wind turbines, and in particular to a method for improving the cooling effect of the stator of a long-core permanent magnet direct-drive wind turbine at high altitudes, which is suitable for large-capacity permanent magnet low-speed wind turbines at high altitudes. Background Art

[0002] Low-speed permanent magnet wind turbine motors have a low speed of only around 10 r / min, and the pressure generated by the rotating components is only a few Pa, which is insufficient to drive air flow within the motor to remove losses during operation. A dedicated fan is generally used as the primary pressure source for air flow. Larger capacity permanent magnet low-speed wind turbine motors, however, have longer cores and utilize radial core ventilation. Cooling air passes through the stator, enters the air gap, diffuses toward both ends of the core, and finally passes through the stator winding ends and ventilation ducts. Because the core is longer, the ventilation path for direct stator cooling is long. Furthermore, due to structural limitations, fans cannot generally be evenly arranged around the circumference of the motor base. Consequently, the circumferential temperature distribution of the stator coils and core is uneven, with circumferential temperature differences reaching 30K-40K. This makes it difficult to further increase the electromagnetic load, impacting the motor's economic efficiency.

[0003] For example, in the Chinese patent, the authorization announcement number is CN110429747B, the authorization announcement date is November 20, 2020, and the name is a method for reducing the circumferential temperature difference between the motor coil and the core. In this method, the cooling air enters the large cavity from the air inlet duct below. The cooling air enters the air gap from the large cavity and cools the end of the stator core at the same time. The cooling air enters the air gap for turbulence and enters the stator ventilation groove for heat exchange. However, the stator core is relatively long. During the journey of the cooling air flowing from the air gap at one end of the stator to the other end of the stator, the temperature of the cooling air is affected by the heat dissipated by the stator core, stator coil, and rotor magnet. The cooling air temperature gradually decreases. The temperature of the cooling air gradually increases, and the cooling effect on the stator end is not significant. The longer the stroke, the higher the temperature of the cooling air flowing to the stator ventilation groove, resulting in uneven cooling of each section of the stator core and low cooling efficiency. The cooling air enters the air inlet cavity from the large cavity. Due to the small radial size of the air inlet cavity, the wind resistance is large, and the amount of cooling air entering is small. On the one hand, the direct contact time with the stator core is short, the time for heat exchange is short, and the heat exchange efficiency is low. On the other hand, when the cooling air flows from one end of the air inlet cavity to the other end, it is affected by the heat dissipated by the stator core and the stator coil. The cooling air temperature gradually increases, resulting in uneven cooling of each section of the stator core and low cooling efficiency.

[0004] Especially for high-altitude, large-capacity, permanent magnet, low-speed wind turbines, cooling is more difficult due to the low air density, which further limits the improvement of the electromagnetic and thermal load parameters of the wind turbines. Summary of the Invention

[0005] To address the deficiencies of the above-mentioned prior art, the present invention provides a method for reducing the temperature difference of the stator of a long-core permanent magnet wind turbine at high altitudes. The cooling air path in the present invention cools the stator core and the stator coil, and each section of the stator core and the stator coil at each section of the stator core receive more sufficient cooling air, thereby improving the cooling effect, reducing the stator temperature difference, and improving the cooling air utilization efficiency, thereby adapting to the unfavorable conditions of lower air density in high altitude areas.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator, characterized by:

[0008] The cooling air enters the annular space from the air inlet duct to cool the non-driving end of the stator coil;

[0009] The cooling air is divided into two paths in the annular space. One path of cooling air enters the first air inlet cavity from the annular space, flows from the first air inlet cavity to the radial ventilation channels distributed on the circumference of the stator core, and enters the air gap. The cooling air flows from the air gap to the first air outlet cavity, which is distributed on the circumference of the stator core, and then enters the first air outlet cavity, and then flows to the second space.

[0010] Another cooling air flows from the annular space to the first space, and enters the fourth space from the ventilation duct. After entering the fourth space, the cooling air cools the driving end of the stator coil. At the same time, the cooling air enters the second air inlet cavity, and flows from the second air inlet cavity to the radial ventilation channels distributed on the circumference of the stator core, and enters the air gap. The cooling air flows from the air gap to the second air outlet cavity, and then flows to the third space and then to the second space. At this point, the two cooling air flows converge and are discharged from the air outlet duct.

[0011] The annular space is the space at the non-driving end of the stator coil, and the air inlet duct is used to allow cooling air to flow into the annular space to cool the non-driving end of the stator coil;

[0012] The first air inlet chamber, the first air outlet chamber, the second air inlet chamber and the second air outlet chamber are cavities between the stator core and the stator base, the first air inlet chamber and the first air outlet chamber are evenly distributed along the stator core, the first air inlet chamber is located between two adjacent first air outlet chambers, the second air inlet chamber and the second air outlet chamber are evenly distributed along the stator core, the second air inlet chamber is located between two adjacent second air outlet chambers, the first air inlet chamber and the second air inlet chamber are on the same axis, the first air outlet chamber and the second air outlet chamber are on the same axis, wherein the first air inlet chamber and the first air outlet chamber cooperate to cool the stator core for half of the length of the air cooling axis, and the second air inlet chamber and the second air outlet chamber cooperate to cool the stator core for the other half of the length of the air cooling axis;

[0013] The second space and the third space are located below the cavity between the stator core and the stator base, the first air outlet cavity is connected to the second space, the second air outlet cavity is connected to the third space, the second space is connected to the third space, the first air outlet cavity is connected to the second space, and the cooling air after heat exchange with the stator core flows from the first air outlet cavity to the second space, and the cooling air after heat exchange with the stator core in the second air outlet cavity flows to the third space to the second space; the first space is located below the annular space and next to the second space, and the annular space is connected to the first space, and the fourth space is located below the third space, the air outlet duct is located in the first space, the air inlet of the air outlet duct is connected to the second space, the ventilation duct is located in the second space, the air inlet of the ventilation duct is connected to the first space, and the air outlet of the ventilation duct is connected to the fourth space, so that cooling air enters the first space from the annular space and flows through the ventilation duct to the fourth space to cool the driving end of the stator coil.

[0014] Furthermore, the first air inlet cavity, the first air outlet cavity, the second air inlet cavity and the second air outlet cavity are surrounded by a first ring plate, a second ring plate, a third ring plate, a fourth ring plate, a fifth ring plate and a plurality of axial rib plates connected between the stator core and the stator base; a fourth ring plate is arranged between the first ring plate and the second ring plate, one end of the fourth ring plate is connected to the first ring plate, and the other end is connected to the second ring plate; a fifth ring plate is arranged between the second ring plate and the third ring plate, one end of the fifth ring plate is connected to the second ring plate, and the other end is connected to the third ring plate, a cavity is surrounded by the first ring plate, the third ring plate, the fourth ring plate and the fifth ring plate, and the cavity is divided into two left and right chambers by the second ring plate, one of the chambers is surrounded by the first ring plate, the second ring plate and the fourth ring plate, and a plurality of axial ribs are arranged in the chamber. The ribs divide the chamber into multiple axial chambers, and the adjacent axial chambers are respectively the second air inlet chamber and the second air outlet chamber; another chamber is surrounded by the second ring plate, the fifth ring plate and the third ring plate, and multiple axial ribs are arranged at intervals in the chamber to divide the chamber into multiple axial chambers, and the adjacent axial chambers are respectively the first air inlet chamber and the first air outlet chamber; a ninth ring plate is arranged between the third ring plate and the second ring plate, and the ninth ring plate is located below the fifth ring plate, one end of the ninth ring plate is connected to the second ring plate, and the other end of the ninth ring plate is connected to the third ring plate, and the second ring plate, the third ring plate, the fifth ring plate and the ninth ring plate form a second space; one end of the oblique conical ring plate is connected to the bottom of the fourth ring plate, and the other end of the conical ring plate is connected to the second ring plate, and the second ring plate, the fourth ring plate and the conical ring plate form a third space.

[0015] Furthermore, the first ring plate is provided with first ventilation holes at intervals along the circumference, and the third ring plate is provided with second ventilation holes at intervals along the circumference, and the projection positions of the first ventilation holes and the second ventilation holes on the circumference are the same, the first ventilation holes are used to connect the second air inlet cavity with the fourth space, and the second ventilation holes are used to connect the first air inlet cavity with the annular space; the fourth ring plate is provided with third ventilation holes at intervals along the circumference, for connecting the second air outlet cavity with the third space; the fifth ring plate is provided with fourth ventilation holes at intervals along the circumference, for connecting the first air outlet cavity with the second space.

[0016] Furthermore, the third ventilation holes are only distributed on the fourth ring plate corresponding to the second air outlet cavity, and the fourth ventilation holes are only distributed on the fifth ring plate corresponding to the first air outlet cavity. The third ventilation holes and the fourth ventilation holes are in the same position on the circumference, but they are alternately spaced with the projection positions of the first ventilation holes and the second ventilation holes on the circumference.

[0017] Furthermore, the second space and the third space are connected through a sixth ventilation hole opened on the second ring plate.

[0018] Furthermore, the stator core is arranged in the rotor cylinder, the rotor magnet is arranged between the rotor cylinder and the stator core, and the ventilation channel steel is arranged between two adjacent stator core sections. The two stator core sections and the ventilation channel steel form a radially separated radial ventilation channel. The tensioning screw passes through multiple sections of the stator core, and both ends of the tensioning screw are fixed with stator end pressure plates; an air gap is set between the rotor magnet and the stator core.

[0019] Furthermore, the rotor cylinder is connected to the rotor non-drive end ring plate, the rotor non-drive end ring plate is connected to the sealing structure M, a copper ring is provided on the third ring plate, a sixth ring plate is provided below the copper ring, the sixth ring plate is located between the third ring plate and the rotor non-drive end ring plate, the sixth ring plate is respectively connected to the third ring plate and the rotor non-drive end ring plate, the sixth ring plate, the third ring plate, the stator end pressure plate, the rotor non-drive end ring plate, and the rotor cylinder form an annular space through which cooling air passes, an air inlet duct is provided on the rotor non-drive end ring plate, the air inlet duct is connected to the annular space, and the annular space is connected to the first air inlet cavity interval; the rotor non-drive end ring plate is connected to one end of the seventh ring plate, an eighth ring plate is provided below the sixth ring plate, the eighth ring plate is located between the third ring plate and the seventh ring plate, one end of the eighth ring plate is connected to the third ring plate, and the other end of the eighth ring plate is connected to the other end of the seventh ring plate, the third ring plate, the sixth ring plate, the seventh ring plate and the eighth ring plate enclose a first space, and fifth ventilation holes are evenly provided along the circumference of the sixth ring plate for connecting the first space with the annular space.

[0020] Furthermore, ventilation channels corresponding to multiple positions are evenly provided on the third ring plate and the seventh ring plate for the air outlet duct to pass through, one end of the air outlet duct is connected to the second space, and the other end passes through the first space; the first ring plate is connected to the annular cone plate, and the first ring plate, the second ring plate, the annular cone plate, the conical ring plate and the rotor cylinder form the fourth space; ventilation channels corresponding to multiple positions are evenly provided on the second ring plate and the third ring plate for the ventilation duct to pass through, one end of the ventilation duct is connected to the fourth space, and the other end is connected to the first space.

[0021] Furthermore, the air gap value is 4-5 mm.

[0022] Furthermore, the axial height of the radial ventilation channel is 3-4 mm.

[0023] Furthermore, the radial dimensions of the first air inlet cavity, the first air outlet cavity, the second air inlet cavity and the second air outlet cavity are not less than 100 mm.

[0024] Furthermore, the total axial length of the multi-segment stator core is more than 1500 mm, the axial length of the stator core is 20-30 mm, and is evenly distributed in the axial direction.

[0025] Furthermore, the air inlet ducts and air outlet ducts are evenly distributed along the circumference, and the number is 6-8, and a blower is installed at the air inlet duct.

[0026] Furthermore, the number of the ventilation ducts is twice or three times the number of the air inlet ducts or the air outlet ducts.

[0027] Furthermore, the number of the sixth ventilation holes is consistent with the number of the third ventilation holes or the fourth ventilation holes, and the positions of the sixth ventilation holes on the circumference are the same as those of the third ventilation holes and the fourth ventilation holes.

[0028] Furthermore, the gap between the annular cone plate and the driving end of the stator coil is set to 30-100 mm.

[0029] Furthermore, the sealing structure M includes a rotor non-driving end ring plate, a sealing mounting ring plate, a pressure block, a C-type seal, and a sealing ring plate; the sealing mounting ring plate, the pressure block, the C-type seal, and the sealing ring plate are installed on the rotor non-driving end ring plate, and grooves for installing the C-type seal are processed on both end faces on the inner diameter side of the rotor non-driving end ring plate, and the C-type seal is fixed with the help of the pressure block, and the C-type seal lips are all facing the inner diameter side, and are squeezed together with the sealing ring plate installed on the sealing mounting ring plate to complete the sealing at the dynamic and static separation of the wind turbine motor.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. The present invention cools the stator core and the stator coil through two air paths. In the first aspect, the radial dimensions of the first air inlet chamber, the first air outlet chamber, the second air inlet chamber, and the second air outlet chamber in the present invention are large, which can reduce wind resistance and ensure that there is sufficient cooling air in the first air inlet chamber and the second air inlet chamber to cool the stator core and the stator coil. After the cooling air exchanges heat with the stator core and the stator coil, it flows smoothly into the first air outlet chamber and the second air outlet chamber.

[0032] 2. In the second aspect of the present invention, the radial dimensions of the first air inlet cavity and the second air inlet cavity are large, the wind resistance is reduced, and sufficient cooling air enters. The cooling air flows from the corresponding air inlet cavity to the radial ventilation channel and the air gap, so that the contact area between the cooling air and the stator core is large enough to enable sufficient heat exchange, high heat exchange efficiency, and significant cooling effect.

[0033] 3. In the third aspect of the present invention, the stator core is divided into two halves for cooling, and the first air inlet chamber and the first air outlet chamber are responsible for cooling half of the stator core, and the second air inlet chamber and the second air outlet chamber are responsible for cooling the other half of the stator core. In addition, the radial size of the air inlet chamber is large, the wind resistance is small, and the cooling air entering is sufficient, so that the air volume and temperature difference of the cooling air between the radial ventilation channels are reduced, so that each section of the stator core and the stator coil at each section of the stator core can obtain more sufficient cooling air, and the motor is evenly cooled in the axial direction, thereby improving the cooling effect and having a significant temperature reduction effect.

[0034] 4. Compared with the prior art, the present invention cools the non-driving end and the lead end copper ring of the stator coil, reducing the distance of the cooling air flowing to the non-driving end of the stator coil and improving the utilization rate of the cooling air.

[0035] 5. In the present invention, each section of the stator core is 20% shorter than the stator core of a conventional large-capacity permanent magnet low-speed wind turbine. Since the stator core and the coil are radially ventilated and cooled, the shorter the radial ventilation channel spacing, the greater the number of radial ventilation channels, which can increase the heat dissipation area of the stator core and the stator coil to a greater extent and improve the cooling effect.

[0036] 6. In the present invention, the axial height of the radial ventilation channel is 3-4 mm, which is more than 10% smaller than that of the prior art. The reduction in the height of the radial ventilation channel can increase the number of radial ventilation channels without significantly increasing the total length of the core, thereby increasing the heat dissipation surface area and improving the cooling effect.

[0037] 7. In the present invention, the air inlet ducts and the air outlet ducts are evenly distributed on the circumference, and the number is 6-8. A blower is installed at the air inlet duct, which is conducive to more uniform flow of cooling air on the circumference.

[0038] In summary, the present invention can improve the cooling effect and reduce the stator temperature difference. Compared with the existing technology, the wind resistance is reduced by more than 30%, the axial temperature difference is reduced by more than 15%, and the circumferential temperature difference is reduced by 15% to 25%, thereby improving the utilization rate of cooling air, thereby enabling wind turbines to adapt to the unfavorable conditions of lower air density in high-altitude areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Longitudinal section of wind turbine generator;

[0040] Figure 2 Non-drive end view of wind turbine generator;

[0041] Figure 3 AA cross-section of wind turbine generator;

[0042] Figure 4 Cross-section of wind turbine motor BB;

[0043] Figure 5 Cross-section of wind turbine CC;

[0044] Figure 6 Expanded view of the cavity;

[0045] Figure 7 Partial view of sealing structure M;

[0046] Figure numerals: 1-rotor cylinder, 2-rotor magnet, 3-rotor non-drive end ring plate, 4-copper ring, 5-sixth ring plate, 6-sealing mounting ring plate, 7-stator coil, 8-stator core, 9-first ring plate, 10-second ring plate, 11-third ring plate, 12-rib plate, 13-fourth ring plate, 14-fifth ring plate, 15-conical ring plate, 16-annular cone plate, 17-fourth space, 18-annular space, 19-first space, 20-ventilation duct, 21-third ventilation hole, 22-fourth ventilation hole, 23-first ventilation hole, 24-second ventilation Hole, 25-sixth ventilation hole, 26-second air outlet cavity, 27-first air outlet cavity, 28-third space, 29-second space, 30-ninth ring plate, 31-seventh ring plate, 32-eighth ring plate, 33-fifth ventilation hole, 34-radial ventilation channel, 35-ventilation channel steel, 36-pressure block, 37-C-type seal, 38-sealing ring plate, 39-air inlet duct, 40-air outlet duct, 41-air gap, 42-stator end pressure plate, 43-tensioning screw, 44-blower, 45-sealing structure M, 46-first air inlet cavity, 47-second air inlet cavity. DETAILED DESCRIPTION

[0047] The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Solid and dashed arrows are used to distinguish between cold air and hot air flow in the drawings, and ⊕ and ⊙ are used in the cross-sectional diagrams to indicate the vertical inflow and outflow directions of the airflow. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] Example 1

[0049] like Figures 1-6 As shown, a method for improving the cooling effect of the stator of a high-altitude long-core permanent magnet direct-drive wind turbine is provided, wherein cooling air enters the annular space 18 from the air inlet duct 39 to cool the non-driving end of the stator coil 7;

[0050] The cooling air is divided into two paths in the annular space 18. One path of the cooling air enters the first air inlet cavity 46 from the annular space 18, flows from the first air inlet cavity 46 to the radial ventilation channels 34 distributed circumferentially on the stator core 8, and enters the air gap 41. The cooling air flows from the air gap 41 to the first air outlet cavity 27, which corresponds to the radial ventilation channels 34 distributed circumferentially on the stator core 8, and then enters the first air outlet cavity 27, and then flows to the second space 29.

[0051] Another cooling air stream flows from the annular space 18 to the first space 19 and enters the fourth space 17 through the ventilation duct 20. After entering the fourth space 17, the cooling air cools the driving end of the stator coil 7. At the same time, the cooling air enters the second air inlet cavity 47 and flows from the second air inlet cavity 47 to the radial ventilation channels 34 distributed circumferentially on the stator core 8 and enters the air gap 41. The cooling air flows from the air gap 41 to the second air outlet cavity 26 and enters the second air outlet cavity 26 through the radial ventilation channels 34 distributed circumferentially on the stator core 8. The cooling air then flows to the third space 28 and then to the second space 29. At this point, the two cooling air streams merge and are discharged from the air outlet duct 40.

[0052] The annular space 18 is the space at the non-driving end of the stator coil 7, and the air inlet duct 39 is used to allow cooling air to flow into the annular space 18 to cool the non-driving end of the stator coil 7;

[0053] The first air inlet chamber 46, the first air outlet chamber 27, the second air inlet chamber 47 and the second air outlet chamber 26 are cavities between the stator core 8 and the stator base. The first air inlet chamber 46 and the first air outlet chamber 27 are evenly distributed along the stator core 8. The first air inlet chamber 46 is located between two adjacent first air outlet chambers 27. The second air inlet chamber 47 and the second air outlet chamber 26 are evenly distributed along the stator core 8. The second air inlet chamber 47 is located between two adjacent second air outlet chambers 26. The first air inlet chamber 46 and the second air inlet chamber 47 are on the same axis, and the first air outlet chamber 27 and the second air outlet chamber 26 are on the same axis. The first air inlet chamber 46 and the first air outlet chamber 27 cooperate to cool the stator core 8 of half the length in the axial direction with air, and the second air inlet chamber 47 and the second air outlet chamber 26 cooperate to cool the stator core 8 of the other half of the length in the axial direction with air.

[0054] The second space 29 and the third space 28 are located below the cavity between the stator core 8 and the stator frame. The first air outlet cavity 27 is connected to the second space 29, the second air outlet cavity 26 is connected to the third space 28, the second space 29 is connected to the third space 28, and the first air outlet cavity 27 is connected to the second space 29. The cooling air after heat exchange with the stator core 8 flows from the first air outlet cavity 27 to the second space 29, and the cooling air after heat exchange with the stator core 8 in the second air outlet cavity 26 flows to the third space 28 and then to the second space 29. The first space 19 is located below the annular space 18 and the second space 29, and the annular space 18 is connected to the first space 19, the fourth space 17 is located below the third space 28, the outlet duct 40 is located in the first space 19, and the air inlet of the outlet duct 40 is connected to the second space 29, the ventilation duct 20 is located in the second space 29, the air inlet of the ventilation duct 20 is connected to the first space 19, and the air outlet of the ventilation duct 20 is connected to the fourth space 17, so that cooling air enters the first space 19 from the annular space 18, flows through the ventilation duct 20 to the fourth space 17, and cools the driving end of the stator coil 7.

[0055] In the prior art, during the process of cooling air flowing from the air gap 41 at one end of the stator to the other end of the stator, the temperature of the cooling air gradually increases due to the heat dissipated by the stator core 8, the stator coil 7, and the rotor magnet 2, and the cooling effect on the stator end is not significant; in practice, if Figure 1As shown, the cooling air enters the annular space 18 from the air inlet duct 39 to cool the non-driving end of the stator coil 7. Compared with the prior art, the non-driving end of the stator coil 7 is cooled, which reduces the distance of the cooling air flowing to the non-driving end of the stator coil 7. On the one hand, the cooling air can contact the non-driving end of the stator coil 7 more quickly. On the other hand, the cooling air passes through the annular space 18, and the heat exchange generated with the annular space 18 is relatively small, so that the temperature difference when the cooling air flows from one end to the other end of the annular space 18 is small, and the cooling effect on the stator core 8 away from the air inlet cavity is good.

[0056] At the same time, the cooling air is divided into two paths. One path of cooling air enters the first air inlet cavity 46 from the annular space 18, flows from the first air inlet cavity 46 to the radial ventilation channels 34 distributed on the circumference of the stator core 8, and enters the air gap 41. The cooling air flows from the air gap 41 to the first air outlet cavity 27, which corresponds to the radial ventilation channels 34 distributed on the circumference of the stator core 8, and then enters the first air outlet cavity 27, and then flows to the second space 29. The other path of cooling air flows from the annular space 18 to the first space 19, and enters the fourth space from the ventilation duct 20. 17. After the cooling air enters the fourth space 17, it cools the driving end of the stator coil 7. At the same time, the cooling air enters the second air inlet cavity 47, and flows from the second air inlet cavity 47 to the radial ventilation channels 34 distributed circumferentially on the stator core 8, and enters the air gap 41. The cooling air flows from the air gap 41 to the second air outlet cavity 26, and then flows to the third space 28 to the second space 29. At this point, the two cooling air flows converge and are discharged from the air outlet duct 40.

[0057] The present invention cools the stator core 8 and the stator coil 7 through two air paths. On the first aspect, the radial dimensions of the first air inlet chamber 46, the first air outlet chamber 27, the second air inlet chamber 47 and the second air outlet chamber 26 in the new air path designed by the present invention are large, which can reduce wind resistance and ensure that there is sufficient cooling air in the first air inlet chamber 46 and the second air inlet chamber 47 to cool the stator core 8 and the stator coil 7. After the cooling air exchanges heat with the stator core 8 and the stator coil 7, it can ensure that the hot air flows smoothly into the first air outlet chamber 27 and the second air outlet chamber 26.

[0058] Secondly, the radial dimensions of the first air inlet cavity 46 and the second air inlet cavity 47 are large, the wind resistance is reduced, and sufficient cooling air enters. The cooling air flows from the corresponding air inlet cavity to the radial ventilation channel 34 and the air gap 41, so that the contact area between the cooling air and the stator core 8 is large enough, the contact time is long, the heat exchange time is long, the heat exchange efficiency is high, and the cooling effect is significant.

[0059] Thirdly, as Figure 1As shown, the stator core 8 is divided into two halves for cooling, and the first air inlet chamber 46 and the first air outlet chamber 27 are responsible for cooling one half of the stator core 8, and the second air inlet chamber 47 and the second air outlet chamber 26 are responsible for cooling the other half of the stator core 8. In addition, the radial size of the air inlet chamber is large, the wind resistance is small, and enough cooling air enters, so that the air volume and temperature difference of the cooling air between the radial ventilation channels 34 are reduced, so that each section of the stator core 8 and the stator coil 7 at each section of the stator core 8 can obtain more sufficient cooling air, and the motor is evenly cooled in the axial direction, thereby improving the cooling effect and having a significant temperature reduction effect.

[0060] Even if the air outlet pipe in the prior art with the authorization announcement number CN110429747B and the authorization announcement date of November 20, 2020, and the name of a method for reducing the circumferential temperature difference between the motor coil and the iron core, is used as the air inlet, the air enters from the air outlet pipe, the cooling air enters the air outlet cavity, flows to the stator ventilation groove corresponding to the air outlet cavity, and is released from the stator after being discharged from the air gap 41. In this process, due to the small radial size of the air outlet cavity and the large wind resistance, the cooling air entering the air outlet cavity is small, which will result in a short contact time of the stator core 8 and the ability to perform heat exchange. The time is short and the heat exchange efficiency is low. When the cooling air flows from one end of the air outlet cavity to the other end, the cooling air temperature gradually rises due to the heat dissipated by the stator core 8 and the stator coil 7. The higher temperature cooling air flows to the stator ventilation groove, resulting in uneven cooling of each section of the stator core 8 and low cooling efficiency. The cooling air flows from the stator ventilation groove to the air gap 41, flows from the air gap 41 to the two ends of the stator, and is released from the stator. Since the cooling air has already exchanged heat with the stator core 8 before flowing from the air gap 41 to the two ends of the stator for cooling, the cooling effect is low. Compared with the present invention, it is also difficult to achieve the cooling effect of the present invention by using the air outlet duct as the air inlet.

[0061] Example 2

[0062] This embodiment further elaborates and supplements the implementation of the present invention on the basis of Embodiment 1.

[0063] like Figures 1-6As shown, the first air inlet cavity 46, the first air outlet cavity 27, the second air inlet cavity 47 and the second air outlet cavity 26 are surrounded by the first ring plate 9, the second ring plate 10, the third ring plate 11, the fourth ring plate 13, the fifth ring plate 14 and a plurality of axial ribs 12 connected between the stator core 8 and the stator base; a fourth ring plate 13 is arranged between the first ring plate 9 and the second ring plate 10, one end of the fourth ring plate 13 is connected to the first ring plate 9, and the other end is connected to the second ring plate 10; a fifth ring plate 14 is arranged between the second ring plate 10 and the third ring plate 11, one end of the fifth ring plate 14 is connected to the second ring plate 10, and the other end is connected to the third ring plate 11, and a cavity is surrounded by the first ring plate 9, the third ring plate 11, the fourth ring plate 13 and the fifth ring plate 14, and the cavity is divided into two left and right chambers by the second ring plate 10, one of which is surrounded by the first ring plate 9, the second ring plate 10 and the fourth ring plate 13, and a plurality of axial ribs 12 are arranged in the cavity. The chamber is divided into multiple axial chambers, and the adjacent axial chambers are respectively the second air inlet chamber 47 and the second air outlet chamber 26; another chamber is surrounded by the second ring plate 10, the fifth ring plate 14 and the third ring plate 11, and multiple axial ribs 12 are arranged at intervals in the chamber to divide the chamber into multiple axial chambers, and the adjacent axial chambers are respectively the first air inlet chamber 46 and the first air outlet chamber 27; a ninth ring plate 30 is arranged between the third ring plate 11 and the second ring plate 10, and the ninth ring plate 30 is located below the fifth ring plate 14. One end of the ninth ring plate 30 is connected to the second ring plate 10, and the other end of the ninth ring plate 30 is connected to the third ring plate 11. The second ring plate 10, the third ring plate 11, the fifth ring plate 14 and the ninth ring plate 30 form a second space 29; one end of the oblique conical ring plate 15 is connected to the bottom of the fourth ring plate 13, and the other end of the conical ring plate 15 is connected to the second ring plate 10, and the second ring plate 10, the fourth ring plate 13 and the conical ring plate 15 form a third space 28.

[0064] The first ring plate 9 is provided with first ventilation holes 23 at intervals along the circumference, and the third ring plate 11 is provided with second ventilation holes 24 at intervals along the circumference, and the projection positions of the first ventilation holes 23 and the second ventilation holes 24 on the circumference are the same, the first ventilation holes 23 are used to connect the second air inlet cavity 47 with the fourth space 17, and the second ventilation holes 24 are used to connect the first air inlet cavity 46 with the annular space 18; the fourth ring plate 13 is provided with third ventilation holes 21 at intervals along the circumference, which are used to connect the second air outlet cavity 26 with the third space 28; the fifth ring plate 14 is provided with fourth ventilation holes 22 at intervals along the circumference, which are used to connect the first air outlet cavity 27 with the second space 29.

[0065] The third ventilation holes 21 are only distributed on the fourth ring plate 13 corresponding to the second air outlet cavity 26, and the fourth ventilation holes 22 are only distributed on the fifth ring plate 14 corresponding to the first air outlet cavity 27. The third ventilation holes 21 and the fourth ventilation holes 22 are at the same position on the circumference, but their projected positions on the circumference are alternately spaced with those of the first ventilation holes 23 and the second ventilation holes 24.

[0066] The second space 29 and the third space 28 are connected through a sixth ventilation hole 25 formed on the second ring plate 10 .

[0067] The stator core 8 is arranged in the rotor cylinder 1, and the rotor magnet 2 is arranged between the rotor cylinder 1 and the stator core 8. A ventilation channel steel 35 is arranged between two adjacent sections of the stator core 8. The two sections of the stator core 8 and the ventilation channel steel 35 form a radially separated radial ventilation channel 34. The tensioning screw 43 passes through the multiple sections of the stator core 8, and both ends of the tensioning screw 43 are fixed with stator end pressure plates 42; an air gap 41 is set between the rotor magnet 2 and the stator core 8.

[0068] During cooling, the heat in the middle of the stator coil 7 , the heat generated by the middle stator core 8 , and the heat generated by the middle rotor magnetic steel 2 are taken away by the cooling air flowing through the radial ventilation channel 34 and the air gap 41 .

[0069] The rotor cylinder 1 is connected to the rotor non-drive end ring plate 3, the rotor non-drive end ring plate 3 is connected to the sealing structure M45, the copper ring 4 is provided on the third ring plate 11, the sixth ring plate 5 is provided below the copper ring 4, the sixth ring plate 5 is located between the third ring plate 11 and the rotor non-drive end ring plate 3, the sixth ring plate 5 is respectively connected to the third ring plate 11 and the rotor non-drive end ring plate 3, the sixth ring plate 5, the third ring plate 11, the stator end pressure plate 42, the rotor non-drive end ring plate 3, and the rotor cylinder 1, forming an annular space 18 through which cooling air passes, an air inlet duct 39 is provided on the rotor non-drive end ring plate 3, and the air inlet duct 39 is connected to the annular The space 18 is connected, and the annular space 18 is connected to the first air inlet cavity 46; the rotor non-driving end ring plate 3 is connected to one end of the seventh ring plate 31, and the eighth ring plate 32 is arranged below the sixth ring plate 5. The eighth ring plate 32 is located between the third ring plate 11 and the seventh ring plate 31. One end of the eighth ring plate 32 is connected to the third ring plate 11, and the other end of the eighth ring plate 32 is connected to the other end of the seventh ring plate 31. The third ring plate 11, the sixth ring plate 5, the seventh ring plate 31 and the eighth ring plate 32 enclose a first space 19, and fifth ventilation holes 33 are evenly arranged along the circumference of the sixth ring plate 5 for connecting the first space 19 with the annular space 18.

[0070] In this embodiment, the non-driving end and the lead end copper ring of the stator coil are cooled, which reduces the distance of the cooling air flowing to the non-driving end of the stator coil and improves the utilization rate of the cooling air.

[0071] The third ring plate 11 and the seventh ring plate 31 are evenly provided with a plurality of corresponding ventilation channels for the passage of the air outlet duct 40. One end of the air outlet duct 40 is connected to the second space 29, and the other end passes through the first space 19. The first ring plate 9 is connected to the annular conical plate 16. The first ring plate 9, the second ring plate 10, the annular conical plate 16, the conical ring plate 15 and the rotor cylinder 1 form a fourth space 17. The second ring plate 10 and the third ring plate 11 are evenly provided with a plurality of corresponding ventilation channels for the passage of the ventilation duct 20. One end of the ventilation duct 20 is connected to the fourth space 17, and the other end is connected to the first space 19.

[0072] The cooling air enters the annular space 18 from the air inlet duct 39 to cool the non-driving end of the stator coil 7;

[0073] The cooling air is divided into two paths in the annular space 18. One path of cooling air flows from the annular space 18 through the second ventilation holes 24 into the first air inlet cavity 46, flows from the first air inlet cavity 46 to the radial ventilation channels 34 distributed circumferentially on the stator core 8, and enters the air gap 41. The cooling air flows from the air gap 41 to the first air outlet cavity 27, which corresponds to the radial ventilation channels 34 distributed circumferentially on the stator core 8, and then enters the first air outlet cavity 27, and flows through the fourth ventilation holes 22 to the second space 29.

[0074] Another cooling air flows from the annular space 18 through the fifth ventilation hole 33 to the first space 19, and enters the fourth space 17 from the ventilation duct 20. After entering the fourth space 17, the cooling air bypasses the annular cone plate 16 to cool the driving end of the stator coil 7. At the same time, the cooling air enters the second air inlet cavity 47 through the first ventilation hole 23, and flows from the second air inlet cavity 47 to the radial ventilation channel 34 distributed circumferentially on the stator core 8, and enters the air gap 41. The cooling air flows from the air gap 41 to the second air outlet cavity 26, and enters the second air outlet cavity 26 through the radial ventilation channel 34 distributed circumferentially on the stator core 8, flows to the third space 28 through the third ventilation hole 21, and flows from the third space 28 to the second space 29 through the sixth ventilation hole 25. At this point, the two cooling air flows converge and are discharged from the air outlet duct 40.

[0075] Example 3

[0076] This embodiment further elaborates and supplements the implementation manner of the present invention on the basis of Embodiment 1 or 2.

[0077] The air gap 41 is 4-5 mm to ensure that the cooling air has sufficient flow space.

[0078] The axial height of the radial ventilation channels 34 is 3-4 mm. This is more than 10% smaller than that of the prior art. This reduction in height allows the number of radial ventilation channels 34 to be increased without significantly increasing the overall length of the core, thereby increasing the heat dissipation surface area and improving the cooling effect.

[0079] The radial dimensions of the first air inlet cavity 46, the first air outlet cavity 27, the second air inlet cavity 47 and the second air outlet cavity 26 are not less than 100 mm. The radial dimensions of the first air inlet cavity 46, the first air outlet cavity 27, the second air inlet cavity 47 and the second air outlet cavity 26 are not less than 100 mm, which can reduce wind resistance and ensure that there is sufficient cooling air in the first air inlet cavity 46 and the second air inlet cavity 47 to cool the stator core 8 and the stator coil 7. After the cooling air exchanges heat with the stator core 8 and the stator coil 7, it can ensure that the hot air flows smoothly into the first air outlet cavity 27 and the second air outlet cavity 26; on the other hand, the wind resistance is reduced, and the cooling air entering is sufficient. The cooling air flows from the corresponding air inlet cavity to the radial ventilation channel 34 and the air gap 41, so that the contact area between the cooling air and the stator core 8 is large, the contact time is long, and it can enter The heat exchange time is long, the heat exchange efficiency is high, and the cooling effect is significant; thirdly, the stator core 8 is divided into two halves for cooling, and the first air inlet chamber 46 and the first air outlet chamber 27 are responsible for cooling half of the stator core 8, and the second air inlet chamber 47 and the second air outlet chamber 26 are responsible for cooling the other half of the stator core 8, and the radial size of the air inlet chamber is large, the wind resistance is small, and the cooling air entering is sufficient, so that the air volume and temperature difference of the cooling air between the radial ventilation channels 34 are reduced, so that each section of the stator core 8 and the stator coil 7 at each section of the stator core 8 can obtain more sufficient cooling air, and the motor is evenly cooled in the axial direction, thereby improving the cooling effect and achieving significant cooling effect.

[0080] The total axial length of the multi-segment stator core 8 is over 1500 mm, with the stator core 8 having an axial length of 20-30 mm and being evenly distributed in the axial direction. Compared with the prior art, each stator core 8 in the present invention is 20% shorter than the stator core 8 of conventional, larger-capacity permanent magnet low-speed wind turbines. Because the stator core 8 and stator coil 7 are cooled by radial ventilation, the shorter the spacing between the radial ventilation channels 34, the greater the heat dissipation area of the stator core 8 and stator coil 7, improving the cooling effect.

[0081] Example 4

[0082] This embodiment further elaborates and supplements the implementation manner of the present invention on the basis of Embodiment 1, Embodiment 2 or Embodiment 3.

[0083] The air inlet ducts 39 and the air outlet ducts 40 are evenly distributed along the circumference, and the number is 6-8. A blower 44 is installed at the air inlet duct 39, which is conducive to more uniform flow of cooling air on the circumference and ensures ventilation and cooling effects.

[0084] The number of ventilation ducts 20 is twice or three times the number of air inlet ducts 39 or air outlet ducts 40. This helps the cooling air to flow more evenly on the circumference, thereby ensuring ventilation and cooling effects.

[0085] The number of the sixth ventilation holes 25 is the same as that of the third ventilation holes 21 or the fourth ventilation holes 22 , and the sixth ventilation holes 25 are located at the same circumferential positions as the third ventilation holes 21 and the fourth ventilation holes 22 .

[0086] The gap between the annular cone plate 16 and the driving end of the stator coil 7 is set to 30-100 mm. The gap between the annular cone plate 16 and the driving end of the stator coil 7 is set to 30-100 mm. Figure 1 As shown, through the cooperation of the annular cone plate 16 and the rotor cylinder 1, the cooling air cools the driving end of the stator coil 7, and at the same time, a part of the cooling air flows to the gap between the annular cone plate 16 and the driving end of the stator coil 7, and flows from the gap to the second air inlet cavity 47; this cooling air is divided into two winds, one cooling air cools the driving end of the stator coil 7, and the other cooling air flows from the gap to the second air inlet cavity 47 to cool the stator core corresponding to the second air inlet cavity 47. The cooling air that cools the driving end of the stator coil 7 cools the driving end of the stator coil 7 and then flows to the second air inlet cavity 47. On the one hand, the utilization rate of the cooling air is improved, and on the other hand, the cooling effect on the driving end of the stator coil 7 is improved and there is sufficient cooling air to cool the stator core.

[0087] The sealing structure M45 includes a rotor non-driving end ring plate 3, a sealing mounting ring plate 6, a pressure block 36, a C-type seal 37, and a sealing ring plate 38; the sealing mounting ring plate 6, the pressure block 36, the C-type seal 37, and the sealing ring plate 38 are installed on the rotor non-driving end ring plate 3; grooves for installing the C-type seal 37 are processed on both end faces on the inner diameter side of the rotor non-driving end ring plate 3, and the C-type seal 37 is fixed with the help of the pressure block 36. The lips of the C-type seal 37 are all facing the inner diameter side, and are squeezed together with the sealing ring plate 38 installed on the sealing mounting ring plate 6 to complete the sealing of the dynamic and static separation of the wind turbine.

Claims

1. A method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator, characterized by: Cooling air enters the annular space (18) from the air inlet duct (39) to cool the non-driving end of the stator coil (7); The cooling air is divided into two paths in the annular space (18). One path of the cooling air enters the first air inlet cavity (46) from the annular space (18), flows from the first air inlet cavity (46) to the radial ventilation channels (34) distributed circumferentially on the stator core (8), and enters the air gap (41). The cooling air flows from the air gap (41) to the radial ventilation channels (34) distributed circumferentially on the first air outlet cavity (27) corresponding to the stator core (8), and then enters the first air outlet cavity (27), and then flows to the second space (29). Another cooling air flows from the annular space (18) to the first space (19), and enters the fourth space (17) from the ventilation duct (20). After entering the fourth space (17), the cooling air cools the driving end of the stator coil (7). At the same time, the cooling air enters the second air inlet cavity (47), and flows from the second air inlet cavity (47) to the radial ventilation channel (34) distributed circumferentially on the stator core (8) and enters the air gap (41). The cooling air flows from the air gap (41) to the second air outlet cavity (26), the radial ventilation channel (34) distributed circumferentially on the stator core (8), and enters the second air outlet cavity (26). Then, the cooling air flows to the third space (28) and then to the second space (29). At this point, the two cooling air flows converge and are discharged from the air outlet duct (40). The annular space (18) is a space at the non-driving end of the stator coil (7), and the air inlet duct (39) is used to allow cooling air to flow into the annular space (18) to cool the non-driving end of the stator coil (7); The first air inlet cavity (46), the first air outlet cavity (27), the second air inlet cavity (47) and the second air outlet cavity (26) are cavities between the stator core (8) and the stator frame. The first air inlet cavity (46) and the first air outlet cavity (27) are evenly distributed along the stator core (8). The first air inlet cavity (46) is located between two adjacent first air outlet cavities (27). The second air inlet cavity (47) and the second air outlet cavity (26) are evenly distributed along the stator core (8). The second air inlet cavity (47) is located between the two adjacent first air outlet cavities (27). Between two adjacent second air outlet cavities (26), the first air inlet cavity (46) and the second air inlet cavity (47) are located on the same axis, and the first air outlet cavity (27) and the second air outlet cavity (26) are located on the same axis, wherein the first air inlet cavity (46) and the first air outlet cavity (27) cooperate to cool the stator core (8) of half the length in the axial direction of the air cooling, and the second air inlet cavity (47) and the second air outlet cavity (26) cooperate to cool the stator core (8) of the other half the length in the axial direction of the air cooling; The second space (29) and the third space (28) are located below the cavity between the stator core (8) and the stator frame. The first air outlet cavity (27) is connected to the second space (29), the second air outlet cavity (26) is connected to the third space (28), the second space (29) is connected to the third space (28), and the first air outlet cavity (27) is connected to the second space (29). The cooling air after heat exchange with the stator core (8) flows from the first air outlet cavity (27) to the second space (29), and the cooling air in the second air outlet cavity (26) after heat exchange with the stator core (8) flows to the third space (28) to the second space (29); the first space (19) is located below the annular space (18). The fourth space (17) is located below the third space (28), the air outlet duct (40) is located in the first space (19), the air inlet of the air outlet duct (40) is connected to the second space (29), the ventilation duct (20) is located in the second space (29), the air inlet of the ventilation duct (20) is connected to the first space (19), and the air outlet of the ventilation duct (20) is connected to the fourth space (17), so that cooling air enters the first space (19) from the annular space (18), flows through the ventilation duct (20) to the fourth space (17), and cools the driving end of the stator coil (7).

2. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 1, characterized in that: The first air inlet cavity (46), the first air outlet cavity (27), the second air inlet cavity (47) and the second air outlet cavity (26) are surrounded by a first ring plate (9), a second ring plate (10), a third ring plate (11), a fourth ring plate (13), a fifth ring plate (14) and a plurality of axial ribs (12) connected between the stator core (8) and the stator frame; a fourth ring plate (13) is provided between the first ring plate (9) and the second ring plate (10); one end of the fourth ring plate (13) is connected to the first ring plate (9), and the other end is connected to the second ring plate (10). A fifth ring plate (14) is provided between the second ring plate (10) and the third ring plate (11), one end of the fifth ring plate (14) is connected to the second ring plate (10), and the other end is connected to the third ring plate (11). A cavity is formed by the first ring plate (9), the third ring plate (11), the fourth ring plate (13) and the fifth ring plate (14). The cavity is divided into two left and right chambers by the second ring plate (10), one of which is formed by the first ring plate (9), the second ring plate (10) and the fourth ring plate (13). A plurality of axial ribs (12) are provided at intervals in the cavity. ) divides the chamber into a plurality of axial chambers, and the adjacent axial chambers are respectively the second air inlet chamber (47) and the second air outlet chamber (26); another chamber is surrounded by the second ring plate (10), the fifth ring plate (14) and the third ring plate (11), and a plurality of axial ribs (12) are arranged at intervals in the chamber to divide the chamber into a plurality of axial chambers, and the adjacent axial chambers are respectively the first air inlet chamber (46) and the first air outlet chamber (27); a ninth ring plate (30) is arranged between the third ring plate (11) and the second ring plate (10), and the ninth ring plate (30) is located between the fifth ring plate (11) and the second ring plate (10). 4) below, one end of the ninth ring plate (30) is connected to the second ring plate (10), and the other end of the ninth ring plate (30) is connected to the third ring plate (11), and the second ring plate (10), the third ring plate (11), the fifth ring plate (14) and the ninth ring plate (30) enclose a second space (29); the fourth ring plate (13) is connected to one end of the oblique conical ring plate (15) below, and the other end of the conical ring plate (15) is connected to the second ring plate (10), and the second ring plate (10), the fourth ring plate (13) and the conical ring plate (15) enclose a third space (28).

3. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 2, characterized in that: The first ring plate (9) is provided with first ventilation holes (23) at intervals along the circumference, and the third ring plate (11) is provided with second ventilation holes (24) at intervals along the circumference, and the projection positions of the first ventilation holes (23) and the second ventilation holes (24) on the circumference are the same, the first ventilation holes (23) are used to connect the second air inlet cavity (47) with the fourth space (17), and the second ventilation holes (24) are used to connect the first air inlet cavity (46) with the annular space (18); the fourth ring plate (13) is provided with third ventilation holes (21) at intervals along the circumference, and is used to connect the second air outlet cavity (26) with the third space (28); and the fifth ring plate (14) is provided with fourth ventilation holes (22) at intervals along the circumference, and is used to connect the first air outlet cavity (27) with the second space (29).

4. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 3, characterized in that: The third ventilation holes (21) are only distributed on the fourth ring plate (13) corresponding to the second air outlet cavity (26), and the fourth ventilation holes (22) are only distributed on the fifth ring plate (14) corresponding to the first air outlet cavity (27). The third ventilation holes (21) and the fourth ventilation holes (22) are at the same position on the circumference, but are alternately spaced from the projected positions of the first ventilation holes (23) and the second ventilation holes (24) on the circumference.

5. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 3, characterized in that: The second space (29) and the third space (28) are connected via a sixth ventilation hole (25) provided on the second ring plate (10).

6. A method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to any one of claims 1 to 5, characterized in that: The stator core (8) is arranged in the rotor cylinder (1), the rotor magnetic steel (2) is arranged between the rotor cylinder (1) and the stator core (8), the ventilation slot steel (35) is arranged between two adjacent sections of the stator core (8), the two sections of the stator core (8) and the ventilation slot steel (35) form a radially separated radial ventilation channel (34), the tensioning screw (43) passes through the multiple sections of the stator core (8), and both ends of the tensioning screw (43) are fixed by the stator end pressure plate (42); an air gap (41) is arranged between the rotor magnetic steel (2) and the stator core (8).

7. A method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to any one of claims 1 to 5, characterized in that: The rotor cylinder (1) is connected to the rotor non-drive end ring plate (3), the rotor non-drive end ring plate (3) is connected to the sealing structure M (45), a copper ring (4) is provided on the third ring plate (11), a sixth ring plate (5) is provided below the copper ring (4), the sixth ring plate (5) is located between the third ring plate (11) and the rotor non-drive end ring plate (3), the sixth ring plate (5) is respectively connected to the third ring plate (11) and the rotor non-drive end ring plate (3), the sixth ring plate (5), the third ring plate (11), the stator end pressure plate (42), the rotor non-drive end ring plate (3), and the rotor cylinder (1), forming an annular space (18) through which cooling air passes, an air inlet duct (39) is provided on the rotor non-drive end ring plate (3), and the air inlet duct (39) is connected to the annular The first air inlet cavity (46) is connected to the third air inlet cavity (18), and the annular space (18) is connected to the first air inlet cavity (46); the rotor non-driving end ring plate (3) is connected to one end of the seventh ring plate (31), an eighth ring plate (32) is provided below the sixth ring plate (5), the eighth ring plate (32) is located between the third ring plate (11) and the seventh ring plate (31), one end of the eighth ring plate (32) is connected to the third ring plate (11), and the other end of the eighth ring plate (32) is connected to the other end of the seventh ring plate (31), the third ring plate (11), the sixth ring plate (5), the seventh ring plate (31) and the eighth ring plate (32) enclose a first air inlet cavity (19), and fifth ventilation holes (33) are evenly provided along the circumference of the sixth ring plate (5) for connecting the first air inlet cavity (19) with the annular space (18).

8. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 7, characterized in that: The third ring plate (11) and the seventh ring plate (31) are evenly provided with a plurality of corresponding ventilation holes for the air outlet duct (40) to pass through, and one end of the air outlet duct (40) is connected to the second space (29), and the other end passes through the first space (19); the first ring plate (9) is connected to the annular cone plate (16), and the first ring plate (9), the second ring plate (10), the annular cone plate (16), the conical ring plate (15) and the rotor cylinder (1) enclose a fourth space (17); the second ring plate (10) and the third ring plate (11) are evenly provided with a plurality of corresponding ventilation holes for the air outlet duct (20) to pass through, and one end of the air outlet duct (20) is connected to the fourth space (17), and the other end is connected to the first space (19).

9. A method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to any one of claims 1 to 5, characterized in that: The air gap (41) has a value of 4-5 mm.

10. A method for improving the cooling effect of a stator of a high-altitude long-core permanent magnet direct-drive wind turbine according to any one of claims 1 to 5, characterized in that: The radial ventilation channel (34) has an axial height of 3-4 mm.

11. A method for improving the cooling effect of a stator of a high-altitude long-core permanent magnet direct-drive wind turbine according to any one of claims 1 to 4, characterized in that: The radial dimensions of the first air inlet cavity (46), the first air outlet cavity (27), the second air inlet cavity (47) and the second air outlet cavity (26) are not less than 100 mm.

12. A method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to any one of claims 1 to 5, characterized in that: The total axial length of the multi-segment stator core (8) is more than 1500 mm, and the axial length of the stator core (8) is 20-30 mm and is evenly distributed in the axial direction.

13. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 8, characterized in that: The air inlet duct (39) and the air outlet duct (40) are evenly distributed along the circumference and are 6 to 8 in number. A blower (44) is installed at the air inlet duct (39).

14. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 13, characterized in that: The number of the ventilation ducts (20) is twice or three times the number of the air inlet ducts (39) or the air outlet ducts (40).

15. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 5, characterized in that: The number of the sixth ventilation holes (25) is the same as the number of the third ventilation holes (21) or the fourth ventilation holes (22), and the sixth ventilation holes (25) are located at the same circumferential position as the third ventilation holes (21) and the fourth ventilation holes (22).

16. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 8, characterized in that: The gap between the annular cone plate (16) and the driving end of the stator coil (7) is set to 30-100 mm.

17. The method for improving the cooling effect of a high-altitude long-core permanent magnet direct-drive wind turbine stator according to claim 7, characterized in that: The sealing structure M (45) comprises a rotor non-driving end ring plate (3), a sealing mounting ring plate (6), a pressure block (36), a C-type seal (37), and a sealing ring plate (38); the sealing mounting ring plate (6), the pressure block (36), the C-type seal (37), and the sealing ring plate (38) are installed on the rotor non-driving end ring plate (3); grooves for installing the C-type seal (37) are processed on both end surfaces on the inner diameter side of the rotor non-driving end ring plate (3), and the C-type seal (37) is fixed with the help of the pressure block (36), and the lips of the C-type seal (37) are all facing the inner diameter side, and are squeezed together with the sealing ring plate (38) installed on the sealing mounting ring plate (6) to complete the sealing of the dynamic and static separation of the wind turbine.

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