A method for welding and assembling a pumped storage air internal cooling magnetic pole coil

Abstract

The application discloses a kind of pumped storage air internal cooling magnetic pole coil welding assembly methods, it is related to pumped storage generator technical field, comprising:S1, welding positioning mould is placed in welding platform, it contains two U-shaped welding positioning pieces and a pair of wedge, middle part is equipped with support platform;S2, adjust wedge to make the long side distance of two U-shaped pieces consistent with the distance of the long side copper bar outside of the coil to be welded;S3, the first four copper bars are placed in support platform, and silver soldering piece is placed in contact position;S4, three corners of three edges of coil are welded in turn using medium-frequency induction heating head, if necessary, welding seam is filled with welding wire;S5, after welding one turn, copper bar sinks, adjust the distance between mould, according to spiral direction first edge copper bar of next turn is placed and welded with last edge of upper turn;S6, the welding of next turn copper bar, repeat S3-S5 steps, in turn weld all copper bars of magnetic pole coil.The application can improve welding precision, ensure the vertical positioning precision of long side and short side after coil welding, reduce subsequent straightening frequency.

Description

Technical Field

[0001] This invention relates to the field of pumped storage generator technology, specifically to a method for welding and assembling an internal cold magnetic pole coil in a pumped storage generator. Background Technology

[0002] Pumped-storage generator motors operate at high speeds and experience significant centrifugal force. To achieve lightweight design, a dual-zone cooling system—internal and external cooling for the rotor poles—is employed to enhance rotor cooling capacity. This reduces the amount of copper busbars used in the poles and decreases the rotor diameter, fundamentally reducing centrifugal force. Large pumped-storage generator motor rotor pole coils typically utilize a multi-turn copper busbar spiral stacked structure, with high-strength insulating paper containing insulating adhesive placed between the turns to ensure inter-turn insulation.

[0003] Chinese invention patent document CN103715803B, published on November 25, 2015, discloses a method for partitioned cooling of rotor magnetic poles, specifically employing the method of creating ventilation channels for internal cooling of the magnetic pole coils by opening holes in the copper busbars of the magnetic poles. However, for the centripetal magnetic poles used in large pumped-storage generator motors, the magnetic pole coils can only use thin copper busbars that are easy to bend into an arc shape, with a thickness of only 4-8 mm. If holes are to be made in the copper busbars, the height of the holes needs to reach a certain value to ensure smooth ventilation. According to engineering experience and calculation analysis, the height needs to be at least close to 3 mm. This would result in a very small remaining structural thickness of the copper busbar at the opening, greatly weakening its load-bearing capacity (for example, with a 6 mm thick magnetic pole copper busbar, after machining a 3 mm hole, the remaining structure of the copper busbar at this point consists of two thin sheets with a thickness of only 1.5 mm), which may lead to the copper busbar breaking. In addition, opening ventilation holes that are too small in the middle of the copper busbar is also very difficult to manufacture and difficult to implement. Therefore, for the above-mentioned magnetic pole coil, it is proposed to process notches at the same position on adjacent copper busbars, then weld them into a spiral stack, insert insulation, and shape them. The two notches at the same position interlock to form an internal cooling ventilation hole.

[0004] However, the precision of the ventilation hole alignment has a decisive impact on the ventilation effect and the appearance quality of the magnetic pole product. Since the long-side copper busbars of the rotor magnetic pole coils of large pumped-storage generator motors, which have internal cooling ventilation channels, are generally over 3 meters long, multiple notches, sometimes even dozens, are usually required to significantly improve the cooling effect. During the processing, using existing methods, due to the excessive length of the copper busbars, it is necessary to ensure both precise notch machining and welding precision. Welding precision includes two aspects: firstly, the axial positioning precision of the long-side copper busbars. If the axial deviation is large after welding, it directly leads to the inability to achieve axial positioning of the ventilation holes; secondly, the angular positioning error between the long and short-side copper busbars. If the angular positioning error is large, the positioning precision of all ventilation holes will gradually become very poor as it extends to the far end. Assuming the perpendicularity of the short side relative to the long side is 0.1mm, then for a magnetic pole coil with a long side of 3m, the deviation of the far end of the long side from the precise position will reach as much as 3mm, such a large deviation is unacceptable. Furthermore, the subsequent pressing and hot pressing processes require a large amount of straightening work to correct the perpendicularity. This not only makes it difficult to ensure the positioning accuracy of the holes, but also causes the internal stress generated by the straightening to remain, resulting in the inter-turn insulation bearing a large tangential force from the beginning. Moreover, the further away from the end, the greater the tangential force will be, which will be very detrimental to ensuring insulation safety. Existing welding processing methods cannot solve the problems of low welding accuracy and excessive straightening frequency when processing long copper busbars.

[0005] Chinese utility model patent document CN203304734U, published on November 27, 2013, discloses a welding fixture for motor magnetic pole coils. The fixture includes a support frame with symmetrical positioning plates on both sides of the upper part of the support frame. The copper busbar of the magnetic pole coil to be welded is placed on the positioning plates. The inner width between the positioning plates matches the inner width of the copper busbar, and the height of the positioning plates matches the height of the welding head of the intermediate frequency induction coil. By placing the copper busbar on the positioning plates on the upper part of the support frame, the copper busbar is accurately positioned, eliminating the need for manual positioning by the operator and preventing movement of the copper busbar during welding. In particular, the heating head of the intermediate frequency induction coil is equipped with a heat insulation plate, which heats only the weld joint of the copper busbar, allowing the weld to melt quickly and completely, greatly improving the welding quality.

[0006] However, the above technical solutions have several drawbacks. First, the use of positioning plates and manual adjustment of support plates for copper busbar welding makes continuous welding of multi-turn coils impossible, and it cannot guarantee the consistency of the reference when stacking multi-turn coils. This affects the accuracy of subsequent multi-turn magnetic pole coil forming and hot pressing, requiring multiple straightening operations during these processes. Furthermore, manually adjusting the support plate to adjust the length of the short-side copper busbar is cumbersome and prone to human error. Second, the lack of a length-direction positioning device makes it impossible to position and fix the long-side copper busbars on both sides of the same turn, and it cannot guarantee the consistency of the copper busbars in the length direction of each turn. Without a positioning device for the short-side copper busbar, it is prone to displacement or deformation during welding, and the perpendicularity between the short-side and long-side copper busbars cannot be guaranteed. The absence of a copper busbar clamping and fixing device also makes it prone to displacement during welding, affecting the welding positioning accuracy and welding quality of the coil. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a welding and assembly method for pumped-storage air-cooled magnetic pole coils. This method improves welding precision, ensures the vertical positioning accuracy of the long and short sides of the magnetic pole coil after welding, reduces the correction frequency during subsequent pressing and hot pressing processes when using copper busbars with an internally cooled magnetic pole coil structure, reduces internal stress retention caused by multiple corrections, and significantly improves manufacturing efficiency and safety.

[0008] This invention is achieved using the following technical solution: A method for welding and assembling pumped-storage air-cooled magnetic pole coils includes welding copper busbars into spirally stacked magnetic pole coils using silver solder brazing, specifically including: S1. Place the welding positioning fixture on the welding platform to form a new welding platform. The welding positioning fixture includes two U-shaped welding positioning parts and a pair of wedges for adjusting the distance between their long sides. A support platform with an end face lower than the end face of the U-shaped welding positioning parts is provided in the middle of the welding positioning fixture. S2. Push the wedge block through the hydraulic device under the welding positioning jig so that the inclined surface of the wedge block contacts the inclined surface on the short side of the U-shaped welding positioning piece, and adjust the height of the wedge block so that the distance between the long sides of the two U-shaped welding positioning pieces is consistent with the distance between the outer sides of the long copper busbar of the first turn of the outermost magnetic pole coil. S3. Place the four copper busbars that make up one turn of magnetic pole coil on the support platform. The four copper busbars include two long copper busbars that are in close contact with the long side of the U-shaped welding positioning component and two short copper busbars that are in close contact with the short side of the U-shaped welding positioning component. The short copper busbars are arranged between the long copper busbars and silver solder sheets are placed at the contact positions. S4. Place the intermediate frequency induction heating head in sequence at the contact positions of the above four copper busbars and clamp them. Turn on the intermediate frequency induction heating head and heat and weld the silver solder pieces at the three corners of the first three copper busbars in sequence according to the spiral direction. After the clamped silver solder pieces melt, observe the welding situation. If the weld is shrinking or not full, fill the weld with welding wire to complete the welding of one turn of magnetic pole coil. S5. After each turn of the coil copper busbar is welded, lower the previously welded copper busbar under the U-shaped welding positioning piece. Repeat step S2 so that the distance between the long sides of the two U-shaped welding positioning pieces is consistent with the distance between the outer sides of the long side copper busbar of the next turn of the magnetic pole coil. Place the first side copper busbar of the next turn in the corresponding position in the spiral direction. Then, make the unwelded end face of the fourth side copper busbar of the previous turn contact with the end face of the first side copper busbar of the next turn, and place a silver solder sheet at the contact position. Perform medium frequency induction heating welding to complete the welding of the connection between adjacent turns of copper busbar. S6. Welding of the next copper busbar: Repeat steps S3-S5 to weld all the copper busbars of the magnetic pole coil in sequence.

[0009] Both U-shaped welding positioning components have locking blocks on their side walls. The locking blocks on the same side are connected by a spring in a stretched state, so that the inclined surface of the short side of the U-shaped welding positioning component and the inclined surface of the wedge block remain in contact under the action of spring tension. The inclined angle of the inclined surface of the short side of the U-shaped welding positioning component and the inclined surface of the wedge block are the same.

[0010] The wedge is raised and lowered by a cylinder, which is controlled by a pre-programmed program in the host computer of the welding equipment.

[0011] The support platform is used to support the welded magnetic pole coil. After each turn of the magnetic pole coil is welded, the support platform is lowered by 20-50mm by a hydraulic device to ensure that the welded magnetic pole coil is supported, so that space can be made for the welding of the next turn of the magnetic pole coil, without affecting the welding of the next turn of the magnetic pole coil.

[0012] The U-shaped welding positioning component has a symmetrical structure and is manufactured using high-precision wire cutting. The perpendicularity between its long side and short side is 0.1-0.2mm.

[0013] In step S4, when filling the weld seam with welding wire, ensure that the welding wire filling material is not higher than the plane of the currently welded copper busbar.

[0014] One of the U-shaped welding positioning components has a notch 1 on the lower surface of one corner for placing the lead end of the first turn magnetic pole coil, and the other U-shaped welding positioning component has a notch 2 on the upper surface of the same side as the notch for placing the lead end of the last turn magnetic pole coil.

[0015] The long copper busbar of the first turn magnetic pole coil at the gap one and the long copper busbar of the last turn magnetic pole coil at the gap two have one more lead than the other long copper busbars.

[0016] The thickness of the silver solder sheet is 0.5 mm.

[0017] The material of the welding wire is the same as that of the silver solder sheet.

[0018] The thickness of the U-shaped welding positioning component is 30-50mm.

[0019] The depth of notch one and notch two is 20mm.

[0020] This also includes inspecting the welds after all the turns of the magnetic pole coils have been welded to ensure that none of the welds are higher than the plane of the copper busbar. If any welds are higher than the plane of the copper busbar, they are ground down to be flush with the plane of the copper busbar and all the debris generated during the grinding is cleaned up.

[0021] Compared with the prior art, the advantages of the present invention are as follows: 1. This invention, through the cooperation of a U-shaped welding positioning component and a wedge, ensures that the inner frame size formed by these components closely matches the long and short sides of each turn of the copper busbar, and achieves precise adjustment of the spacing between the long sides. This ensures perfect matching with copper busbars of different sizes. After welding the copper busbar joints, the perpendicularity of the long and short sides of each turn of the welded copper busbar is basically consistent with the perpendicularity of the long and short sides of the U-shaped welding positioning component. This ensures the vertical positioning accuracy of the long and short sides after the complete welding of the magnetic pole coil, thereby ensuring the welding forming accuracy of the entire coil. This lays a good foundation for the manufacturing accuracy of the subsequent magnetic pole coil and also improves the positioning accuracy of the notches used to form the ventilation holes after the adjacent long side copper busbars are processed.

[0022] 2. In this invention, through the cooperation of the spring system and wedge between the two U-shaped welded positioning parts, the spring is in a stretched state to provide constant tension, which forces the short side inclined surface of the U-shaped part to always fit tightly with the wedge inclined surface without gap, thus ensuring the size and vertical positioning accuracy of the inner frame formed, thereby ensuring the positioning accuracy of the long and short sides of the magnetic pole coil.

[0023] 3. This invention features a cylinder-driven wedge block lifting mechanism with fast response, accurate positioning, and programmability. Through upper computer program control, it achieves automation, standardization, and repeatability of wedge block height adjustment, reducing manual intervention, improving production cycle time and consistency, and ensuring efficient control of the positioning accuracy of each turn.

[0024] 4. In this invention, the support platform is hydraulically controlled, allowing for stable and controllable sinking. The sinking amount of 20-50mm is designed to precisely balance the two requirements of supporting the welded coil to prevent deformation and leaving sufficient operating space for the upper layer welding. This ensures stable support for the lower layer coils without interfering with the upper layer welding operation, and guarantees that the reference of all stacked coils is consistent.

[0025] 5. In this invention, the U-shaped welding positioning component is processed by high-precision wire cutting to ensure its own extremely high geometric accuracy, thereby making the magnetic pole coil welded by it highly accurate.

[0026] 6. The present invention uses induction heating brazing to minimize the heat input at the welding position, thereby controlling welding deformation as much as possible.

[0027] 7. The present invention, by inserting silver solder pads between the long and short copper busbars of the magnetic pole coil during welding, can better ensure the strength and quality of the weld.

[0028] 8. This invention, by appropriately filling the weld seam with silver solder wire, can ensure that the bevel angle of the weld seam after positioning by a high-precision welding positioning jig due to the processing error of the long and short copper busbars is well filled, so as to compensate for the contact surface of the long and short copper busbars, so that the molten silver solder fills the gap, and ensures that the shrinkage caused by the fusion of silver solder in the large gap is prevented, thereby ensuring the weld seam connection quality.

[0029] 9. In this invention, after welding is completed, all welds are inspected to ensure that there are no welds higher than the plane. Welds that exceed the standard are finely ground to be flush and debris is thoroughly cleaned. In the end, the overall outer surface of the coil is guaranteed to be absolutely smooth and flat, ensuring the accuracy and safety performance of the air-cooled coil. Attached Figure Description

[0030] Figure 1 This is a flowchart of the method steps of the present invention; Figure 2 This is a schematic diagram illustrating the positioning during the welding process of this invention; Figure 3 This is a schematic diagram of the welding positioning fixture of the present invention; Figure 4 This is a schematic diagram of the spiral stacked structure welded according to the present invention; Figure 5 This is a schematic diagram of the copper busbar notch-type internal cooling duct magnetic pole coil after molding.

[0031] Marked in the image: 1. U-shaped welding positioning component; 2. Wedge block; 3. Support platform; 4. Long side copper busbar; 5. Short side copper busbar; 6. Medium frequency induction heating head; 7. Locking block; 8. Spring; 9. Notch 1; 10. Notch 2; 11. Lead wire end; 12. Interlocking cold air duct. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1 As the most basic embodiment of the present invention, refer to Figure 1-5 A method for welding and assembling pumped-storage air-cooled magnetic pole coils includes welding copper busbars into spirally stacked magnetic pole coils using silver solder brazing, specifically including: S1. Place the welding positioning fixture on the welding platform to form a new welding platform. The welding positioning fixture includes two U-shaped welding positioning parts 1 and a pair of wedges 2 for adjusting the distance between their long sides. A support platform 3 with its end face lower than the end face of the U-shaped welding positioning parts 1 is provided in the middle of the welding positioning fixture. S2. The wedge 2 is pushed by the hydraulic device under the welding positioning jig so that the inclined surface of the wedge 2 contacts the inclined surface on the short side of the U-shaped welding positioning piece 1, and the height position of the wedge 2 is adjusted so that the distance between the long sides of the two U-shaped welding positioning pieces 1 is the same as the distance between the outer sides of the long side copper busbar 4 of the outermost first turn of the magnetic pole coil. S3. Place the four copper busbars that make up the first turn of the magnetic pole coil on the support platform 3. The four copper busbars include two long copper busbars 4 that are in close contact with the long side of the U-shaped welding positioning part 1 and two short copper busbars 5 that are in close contact with the short side of the U-shaped welding positioning part 1. The short copper busbars 5 are arranged between the long copper busbars 4 and silver solder sheets are placed at the contact position. S4. Place the intermediate frequency induction heating head 6 in sequence at the contact positions of the above four copper busbars and clamp them. Turn on the intermediate frequency induction heating head 6 and heat and weld the silver solder pieces at the three corners of the first three copper busbars in the spiral direction. After the clamped silver solder pieces melt, observe the welding situation. If the weld is shrinking or not full, fill the weld with welding wire to complete the welding of one turn of magnetic pole coil. S5. After each turn of the coil copper busbar is welded, lower the previously welded copper busbar below the U-shaped welding positioning piece 1 and repeat step S2 so that the distance between the long sides of the two U-shaped welding positioning pieces 1 is consistent with the distance between the outer sides of the long side copper busbar 4 of the next turn of the magnetic pole coil. Place the first side copper busbar of the next turn in the corresponding position in the spiral direction, and then contact the unwelded end face of the fourth side copper busbar of the previous turn with the end face of the first side copper busbar of the next turn. Place a silver solder sheet at the contact position and perform medium frequency induction heating welding to complete the welding of the connection between adjacent turns of copper busbar. S6. Welding of the next copper busbar: Repeat steps S3-S5 to weld all the copper busbars of the magnetic pole coil in sequence.

[0034] In this embodiment, high-precision control of the position and perpendicularity of the copper busbar of the magnetic pole coil is achieved through welding positioning jigs and precise welding processes. This solves the problem of cumulative positioning errors of ventilation holes over long distances, ensuring high-precision alignment of the ventilation holes. Simultaneously, high-precision welding significantly reduces the need for subsequent straightening, effectively eliminates residual stress from straightening, protects the safety and reliability of inter-turn insulation, improves the long-term operational stability of the product, and enhances welding quality, production efficiency, and ease of operation.

[0035] Example 2 As a preferred embodiment of the present invention, refer to Figure 1-5 A method for welding and assembling pumped-storage air-cooled magnetic pole coils includes welding copper busbars into spirally stacked magnetic pole coils using silver solder brazing, specifically including: S1. Place the welding positioning fixture on the welding platform to form a new welding platform. The welding positioning fixture includes two U-shaped welding positioning parts 1 and a pair of wedges 2 for adjusting the distance between their long sides. A support platform 3 with its end face lower than the end face of the U-shaped welding positioning parts 1 is provided in the middle of the welding positioning fixture. Each of the two U-shaped welding positioning parts 1 has a locking block 7 on its side wall. The locking blocks 7 on the same side are connected by a spring 8 in a stretched state, so that the inclined surface of the short side of the U-shaped welding positioning part 1 and the inclined surface of the wedge 2 are kept in contact under the tension of the spring 8. The angle between the inclined surface of the short side of the U-shaped welding positioning part 1 and the inclined surface of the wedge 2 is the same. The wedge 2 is raised and lowered by a cylinder, and the cylinder is controlled by a preset program in the host computer of the welding equipment. S2. The wedge 2 is pushed by the hydraulic device under the welding positioning jig so that the inclined surface of the wedge 2 contacts the inclined surface on the short side of the U-shaped welding positioning piece 1, and the height position of the wedge 2 is adjusted so that the distance between the long sides of the two U-shaped welding positioning pieces 1 is the same as the distance between the outer sides of the long side copper busbar 4 of the outermost first turn of the magnetic pole coil. S3. Place the four copper busbars that make up the first turn of the magnetic pole coil on the support platform 3. The four copper busbars include two long copper busbars 4 that are in close contact with the long side of the U-shaped welding positioning part 1 and two short copper busbars 5 that are in close contact with the short side of the U-shaped welding positioning part 1. The short copper busbars 5 are arranged between the long copper busbars 4 and silver solder sheets are placed at the contact position. S4. Place the intermediate frequency induction heating head 6 in sequence at the contact positions of the above four copper busbars and clamp them. Turn on the intermediate frequency induction heating head 6 and heat and weld the silver solder pieces at the three corners of the first three copper busbars in the spiral direction. After the clamped silver solder pieces melt, observe the welding situation. If the weld is shrinking or not full, fill the weld with welding wire to complete the welding of one turn of magnetic pole coil. S5. After each turn of the coil copper busbar is welded, lower the previously welded copper busbar below the U-shaped welding positioning piece 1 and repeat step S2 so that the distance between the long sides of the two U-shaped welding positioning pieces 1 is consistent with the distance between the outer sides of the long side copper busbar 4 of the next turn of the magnetic pole coil. Place the first side copper busbar of the next turn in the corresponding position in the spiral direction, and then contact the unwelded end face of the fourth side copper busbar of the previous turn with the end face of the first side copper busbar of the next turn. Place a silver solder sheet at the contact position and perform medium frequency induction heating welding to complete the welding of the connection between adjacent turns of copper busbar. S6. Welding of the next copper busbar: Repeat steps S3-S5 to weld all the copper busbars of the magnetic pole coil in sequence.

[0036] In this embodiment, the two U-shaped welding positioning parts 1 are pulled towards the center by two pairs of locking blocks 7 connected with springs 8, ensuring that the inclined surface of its short side is always in close contact with the inclined surface of the wedge block 2. The preload of the springs 8 provides continuous clamping force to maintain contact rigidity, and the tension of the springs 8 can adaptively compensate for minor machining errors of the inclined surface to ensure effective contact throughout the entire contact area. By using cylinders and programmed control to raise and lower the wedge block 2, high-precision, repeatable, and automated welding settings are achieved, providing technical assurance for the consistency of multi-turn continuous welding.

[0037] Example 3 As another preferred embodiment of the present invention, refer to Figure 1-5 A method for welding and assembling pumped-storage air-cooled magnetic pole coils includes welding copper busbars into spirally stacked magnetic pole coils using silver solder brazing, specifically including: S1. Place the welding positioning fixture on the welding platform to form a new welding platform. The welding positioning fixture includes two U-shaped welding positioning parts 1 manufactured by high-precision wire cutting and a pair of wedges 2 for adjusting the distance between their long sides. A support platform 3 is provided in the middle of the welding positioning fixture, with its end face lower than the end face of the U-shaped welding positioning part 1. The support platform 3 is used to support the welded magnetic pole coil. Each of the two U-shaped welding positioning parts 1 has a locking block 7 on its side wall. The locking blocks 7 on the same side are connected by a spring 8 in a stretched state, so that the inclined surface of the short side of the U-shaped welding positioning part 1 and the inclined surface of the wedge 2 are kept in contact under the tension of the spring 8. The angle between the inclined surface of the short side of the U-shaped welding positioning part 1 and the inclined surface of the wedge 2 is the same. The wedge 2 is raised and lowered by a cylinder, and the cylinder is controlled by a preset program in the host computer of the welding equipment. The U-shaped welding positioning part 1 has a symmetrical structure, and the perpendicularity between its long side and short side is 0.1-0.2mm. S2. The wedge 2 is pushed by the hydraulic device under the welding positioning jig so that the inclined surface of the wedge 2 contacts the inclined surface on the short side of the U-shaped welding positioning piece 1, and the height position of the wedge 2 is adjusted so that the distance between the long sides of the two U-shaped welding positioning pieces 1 is the same as the distance between the outer sides of the long side copper busbar 4 of the outermost first turn of the magnetic pole coil. S3. Place the four copper busbars that make up the first turn of the magnetic pole coil on the support platform 3. The four copper busbars include two long copper busbars 4 that are in close contact with the long side of the U-shaped welding positioning part 1 and two short copper busbars 5 that are in close contact with the short side of the U-shaped welding positioning part 1. The short copper busbars 5 are arranged between the long copper busbars 4 and silver solder sheets are placed at the contact position. S4. Place the intermediate frequency induction heating head 6 in sequence at the contact positions of the above four copper busbars and clamp them. Turn on the intermediate frequency induction heating head 6 and heat and weld the silver solder pieces at the three corners of the first three copper busbars in the spiral direction. After the clamped silver solder pieces melt, observe the welding situation. If the weld is shrinking or not full, fill the weld with welding wire to complete the welding of one turn of magnetic pole coil. S5. After each turn of the coil copper busbar is welded, the copper busbar of the previous turn is lowered by 20-50mm using the hydraulic device to lower the support platform 3 so that the copper busbar of the previous turn is lowered under the U-shaped welding positioning piece 1, ensuring that the welded magnetic pole coil is supported so that it can make room for the welding of the next turn without affecting the welding of the next turn of the magnetic pole coil. Repeat step S2 so that the distance between the long sides of the two U-shaped welding positioning pieces 1 is consistent with the distance between the outer sides of the long side copper busbar 4 of the next turn of the magnetic pole coil. Place the first side copper busbar of the next turn in the corresponding position in the spiral direction, and then contact the unwelded end face of the fourth side copper busbar of the previous turn with the end face of the first side copper busbar of the next turn. Place a silver solder sheet at the contact position and perform medium frequency induction heating welding to complete the welding of the connection between adjacent turns of copper busbar. S6. Welding of the next copper busbar: Repeat steps S3-S5 to weld all the copper busbars of the magnetic pole coil in sequence.

[0038] In this embodiment, the support platform 3 is hydraulically controlled, allowing for a smooth and controllable descent. The 20-50mm descent is designed to precisely balance the two requirements of supporting the welded coil to prevent deformation and leaving sufficient operating space for the upper layer welding, ensuring stable support for the lower layer coil without interfering with the upper layer welding operation. Furthermore, the U-shaped welding positioning component 1 is processed with high-precision wire cutting to ensure its own extremely high geometric accuracy, thereby making the magnetic pole coil welded using it highly accurate.

[0039] Example 4 As a preferred embodiment of the present invention, refer to Figure 1-5 A method for welding and assembling pumped-storage air-cooled magnetic pole coils includes welding copper busbars into spirally stacked magnetic pole coils using silver solder brazing, specifically including: S1. Place the welding positioning fixture on the welding platform to form a new welding platform. The welding positioning fixture includes two U-shaped welding positioning parts 1 manufactured by high-precision wire cutting and a pair of wedges 2 for adjusting the distance between their long sides. A support platform 3 is provided in the middle of the welding positioning fixture, with its end face lower than the end face of the U-shaped welding positioning part 1. The support platform 3 is used to support the welded magnetic pole coil. Each of the two U-shaped welding positioning parts 1 has a locking block 7 on its side wall. The locking blocks 7 on the same side are connected by a spring 8 in a stretched state, so that the inclined surface of the short side of the U-shaped welding positioning part 1 and the inclined surface of the wedge 2 are kept in contact under the tension of the spring 8. The angle between the inclined surface of the short side of the U-shaped welding positioning part 1 and the inclined surface of the wedge 2 is the same. The wedge 2 is raised and lowered by a cylinder, and the cylinder is controlled by a preset program in the host computer of the welding equipment. The U-shaped welding positioning part 1 has a symmetrical structure, and the perpendicularity between its long side and short side is 0.1-0.2mm. S2. The wedge 2 is pushed by the hydraulic device under the welding positioning jig so that the inclined surface of the wedge 2 contacts the inclined surface on the short side of the U-shaped welding positioning piece 1, and the height position of the wedge 2 is adjusted so that the distance between the long sides of the two U-shaped welding positioning pieces 1 is the same as the distance between the outer sides of the long side copper busbar 4 of the outermost first turn of the magnetic pole coil. S3. Place the four copper busbars that make up the first turn of the magnetic pole coil on the support platform 3. The four copper busbars include two long copper busbars 4 that are in close contact with the long side of the U-shaped welding positioning part 1 and two short copper busbars 5 that are in close contact with the short side of the U-shaped welding positioning part 1. The short copper busbars 5 are arranged between the long copper busbars 4, and a silver solder sheet with a thickness of 0.5mm is placed at the contact position. S4. Place the intermediate frequency induction heating head 6 in sequence at the contact positions of the above four copper busbars and clamp them. Turn on the intermediate frequency induction heating head 6 and heat and weld the silver solder pieces at the three corners of the first three copper busbars in the spiral direction. After the clamped silver solder pieces melt, observe the welding situation. If the weld is shrinking or not full, fill the weld with welding wire to complete the welding of one turn of magnetic pole coil. S5. After each turn of the coil copper busbar is welded, the copper busbar of the previous turn is lowered by 20-50mm using the hydraulic device to lower the support platform 3 so that the copper busbar of the previous turn is lowered under the U-shaped welding positioning piece 1, ensuring that the welded magnetic pole coil is supported so that it can make room for the welding of the next turn without affecting the welding of the next turn of the magnetic pole coil. Repeat step S2 so that the distance between the long sides of the two U-shaped welding positioning pieces 1 is consistent with the distance between the outer sides of the long side copper busbar 4 of the next turn of the magnetic pole coil. Place the first side copper busbar of the next turn in the corresponding position in the spiral direction, and then contact the unwelded end face of the fourth side copper busbar of the previous turn with the end face of the first side copper busbar of the next turn. Place a silver solder sheet at the contact position and perform medium frequency induction heating welding to complete the welding of the connection between adjacent turns of copper busbar. S6. Welding of the next copper busbar: Repeat steps S3-S5 to weld all the copper busbars of the magnetic pole coil in sequence.

[0040] In this embodiment, the thickness of the U-shaped welding positioning component 1 is 30-50mm. One corner of the lower surface of one U-shaped welding positioning component 1 is provided with a notch 9 for placing the lead end of the first turn magnetic pole coil. The upper surface of the other U-shaped welding positioning component 1 is provided with a notch 10 for placing the lead end of the last turn magnetic pole coil at a diagonal position on the same side as the notch 9. The depth of the notch 9 and the notch 10 is 20mm. The long side copper busbar 4 of the first turn magnetic pole coil at the notch 9 and the long side copper busbar 4 of the last turn magnetic pole coil at the notch 10 have one more lead end 11 than the other long side copper busbars 4.

[0041] This embodiment also includes inspecting the welds after all the turns of the magnetic pole coils are welded to ensure that none of the welds are higher than the plane of the copper busbar. If there are welds higher than the plane of the copper busbar, they are ground down to be flush with the plane of the copper busbar and all the debris generated during grinding is cleaned up.

[0042] This embodiment can ensure the vertical positioning accuracy of the long and short sides of the magnetic pole coil after welding, reduce the correction frequency in the subsequent pressing and hot pressing process when the copper busbar of the magnetic pole coil with internal cooling structure is used, reduce the internal stress retention caused by multiple corrections, and greatly improve manufacturing efficiency and safety.

Claims

1. A method for welding and assembling internal cold magnetic pole coils in a pumped-storage hydroelectric system, characterized in that, This includes using silver solder to braze copper busbars into spirally stacked magnetic pole coils, specifically including: S1. Place the welding positioning fixture on the welding platform to form a new welding platform. The welding positioning fixture includes two U-shaped welding positioning parts (1) and a pair of wedges (2) for adjusting the distance between their long sides. A support platform (3) with an end face lower than the end face of the U-shaped welding positioning parts (1) is provided in the middle of the welding positioning fixture. S2. Push the wedge (2) through the hydraulic device under the welding positioning jig so that the inclined surface of the wedge (2) contacts the inclined surface on the short side of the U-shaped welding positioning piece (1), and adjust the height position of the wedge (2) so that the distance between the long sides of the two U-shaped welding positioning pieces (1) is consistent with the length of the distance between the outer sides of the long side copper busbar (4) of the outermost first turn of the magnetic pole coil. S3. Place the four copper busbars that make up a coil of magnetic poles on the support platform (3). The four copper busbars include two long copper busbars (4) that are in close contact with the long side of the U-shaped welding positioning piece (1) and two short copper busbars (5) that are in close contact with the short side of the U-shaped welding positioning piece (1). The short copper busbars (5) are arranged between the long copper busbars (4) and silver solder sheets are placed at the contact position. S4. Place the intermediate frequency induction heating head (6) in sequence at the contact position of the above four copper busbars and clamp it. Open the intermediate frequency induction heating head (6) and heat and weld the silver solder pieces at the three corners of the first three copper busbars in sequence according to the spiral direction. After the clamped silver solder pieces melt, observe the welding situation. If the weld is shrinking or not full, fill the weld with welding wire to complete the welding of one turn of magnetic pole coil. S5. After each turn of the coil copper busbar is welded, the welded copper busbar is lowered under the U-shaped welding positioning piece (1). Repeat step S2 so that the distance between the long sides of the two U-shaped welding positioning pieces (1) is consistent with the distance between the outer sides of the long side copper busbar (4) of the next turn of the magnetic pole coil. Place the first side copper busbar of the next turn in the corresponding position in the spiral direction. Then, make the unwelded end face of the fourth side copper busbar of the previous turn contact with the end face of the first side copper busbar of the next turn. Place a silver solder sheet at the contact position and perform medium frequency induction heating welding to complete the welding of the connection between adjacent turns of copper busbar. S6. Welding of the next copper busbar: Repeat steps S3-S5 to weld all the copper busbars of the magnetic pole coil in sequence.

2. The method for welding and assembling a pumped-storage air-cooled magnetic pole coil according to claim 1, characterized in that: Both U-shaped welding positioning parts (1) are provided with locking blocks (7) on their side walls. The locking blocks (7) on the same side are connected by springs (8) in a stretched state, so that the inclined surface of the short side of the U-shaped welding positioning part (1) and the inclined surface of the wedge (2) are kept in contact under the tension of the spring (8). The inclined angle of the inclined surface of the short side of the U-shaped welding positioning part (1) and the inclined surface of the wedge (2) are the same.

3. The method for welding and assembling a pumped-storage air-cooled magnetic pole coil according to claim 2, characterized in that: The wedge (2) is raised and lowered by a cylinder, and the cylinder is controlled by a preset program in the host computer of the welding equipment.

4. The welding and assembly method for an internal cold magnetic pole coil in a pumped-storage hydroelectric system according to claim 3, characterized in that: The support platform (3) is used to receive the welded magnetic pole coil. After each turn of the magnetic pole coil is welded, the support platform (3) is lowered by 20-50mm by the hydraulic device to ensure that the welded magnetic pole coil is supported so that it can make room for the next turn of welding without affecting the welding of the next turn of the magnetic pole coil.

5. The method for welding and assembling a pumped-storage air-cooled magnetic pole coil according to claim 4, characterized in that: The U-shaped welding positioning part (1) has a symmetrical structure and is made by high-precision wire cutting. The perpendicularity between its long side and short side is 0.1-0.2mm.

6. The method for welding and assembling a pumped-storage air-cooled magnetic pole coil according to claim 5, characterized in that: In step S4, when filling the weld seam with welding wire, ensure that the welding wire filling material is not higher than the plane of the currently welded copper busbar.

7. A welding and assembly method for an internal cold magnetic pole coil in a pumped-storage hydroelectric system according to any one of claims 1-6, characterized in that: One of the U-shaped welding positioning parts (1) has a notch 1 (9) on the lower surface of one corner for placing the lead end of the first turn magnetic pole coil, and another U-shaped welding positioning part (1) has a notch 2 (10) on the upper surface of the other part at the diagonal on the same side as the notch 1 (9) for placing the lead end of the last turn magnetic pole coil.

8. The method for welding and assembling a cold magnetic pole coil inside a pumped-storage hydroelectric power plant according to claim 7, characterized in that: The long copper busbar (4) of the first turn magnetic pole coil at the first gap (9) and the long copper busbar (4) of the last turn magnetic pole coil at the second gap (10) have one more lead (11) than the other long copper busbars (4).

9. The method for welding and assembling a cold magnetic pole coil inside a pumped-storage hydroelectric power system according to claim 7, characterized in that: The thickness of the silver solder sheet is 0.5 mm.

10. A method for welding and assembling a pumped-storage air-cooled magnetic pole coil according to claim 9, characterized in that: The material of the welding wire is the same as that of the silver solder sheet.

11. The method for welding and assembling a pumped-storage air-cooled magnetic pole coil according to claim 10, characterized in that: The thickness of the U-shaped welding positioning part (1) is 30-50mm.

12. The method for welding and assembling a pumped-storage air-cooled magnetic pole coil according to claim 11, characterized in that: The depth of the first (9) and the second (10) gaps is 20 mm.

13. The method for welding and assembling a pumped-storage air-cooled magnetic pole coil according to claim 12, characterized in that: This also includes inspecting the welds after all the turns of the magnetic pole coils have been welded to ensure that none of the welds are higher than the plane of the copper busbar. If any welds are higher than the plane of the copper busbar, they are ground down to be flush with the plane of the copper busbar and all the debris generated during the grinding is cleaned up.

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