Double-fed wind power generator rotor connection line structure, wound rotor and generator thereof

Abstract

The application belongs to the technical field of wind driven generators, and relates to a double-fed wind driven generator rotor connecting wire structure, a winding type rotor and a generator thereof. The winding type rotor is formed by improving a rotor connecting wire fixing frame, a rotor zero ring, a reinforcing support frame and a rotor connecting wire circular arc bending structure, and has an integrated winding type rotor connecting wire structure. After installation, the winding type rotor has higher reliability and better mechanical performance in the life test under severe working conditions. Meanwhile, the compact structure of the improved rotor fan shortens the axial distance from the rotor fan to the rotor core and the rotor winding, thereby improving the space utilization rate of the generator and improving the temperature rise performance of the generator rotor.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine technology, and relates to wound-rotor generator rotors, specifically to a doubly fed wind turbine generator rotor connection wire structure, a wound-rotor, and its generator. Background Technology

[0002] With the increasing power ratings of wind turbines and the growing cost pressures in the wind power industry, space within the wind turbine nacelle is extremely limited. Improving the overall reliability of the generator, maximizing the utilization of internal space, and reducing the cost of wind power generation are crucial technical challenges that must be addressed. Therefore, how to make the most of the limited space within the nacelle and generator, while simultaneously improving the reliability of the generator and its components, has become a key aspect of wind turbine design.

[0003] Currently, the fixing structures of the connecting wires and zero rings of mainstream wound rotors both domestically and internationally are as follows: Figure 3 As shown. The rotor core 10, rotor winding support 2, and rotor connecting wire fixing bracket 3 are fixed to the rotating shaft 11 by an interference fit through their respective inner circles; the rotor winding 1 is connected to the rotor connecting wire 5 (its structure is shown in the diagram). Figure 1 The rotor connecting wire 5 is connected to the rotor lead wire 9 or the rotor zero ring 13. The rotor connecting wire 5 is tied and fixed to the rotor connecting wire fixing frame 3 (which has a groove in its cross section for binding and positioning, but is not a closed structure) by the insulating binding tape 6. The rotor zero ring 13 is fixed to the surface of the rotating shaft 11 by the outer ring insulating binding tape 6. The rotor connecting wire 5 and the rotor lead wire 9 are important components for bidirectional energy flow between the converter and the rotor winding 4. Their reliability design is directly related to the operating stability of the wind turbine generator set.

[0004] However, existing wound rotors still have the following shortcomings: First, the rotor connecting wire fixing bracket has a single function and the reliability of this fixing structure is at risk under harsh working conditions; Second, the R angle at the 90° bend of the rotor connecting wire is usually implemented according to national standards, which poses a risk of stress concentration under harsh working conditions; Third, the reliability of the rotor zero ring fixing structure is at risk under harsh working conditions; Fourth, the structural integration of the rotor connecting wire, rotor zero ring, and rotor winding support is poor; Fifth, the axial space between the rotor connecting wire and the fan (or between the fan and the end cover if there is no fan) is not fully utilized. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a doubly-fed wind turbine rotor connection wire structure, a wound rotor, and its generator. This wound rotor provides a more reliable rotor connection wire and rotor zero-ring fixing structure, while reducing the overall axial space occupancy of the rotor (including the fan), thus improving the reliability of the doubly-fed wind turbine rotor structure under harsh operating conditions.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a rotor connection wire structure for a doubly fed wind turbine, comprising an integrally formed rotor connection wire body. The rotor connection wire body includes a first connection portion connected to the rotor winding. Below the first connection portion, a torsion connection portion, a second connection portion connected to the end face of the rotor winding support, and an arc-shaped connection portion for reducing stress at the bending point of the rotor connection wire body are sequentially distributed. The arc-shaped connection portion is connected to a horizontal third connection portion. The connection between the second connection portion and the arc-shaped connection portion forms a first transition arc, and the connection between the arc-shaped connection portion and the horizontal third connection portion forms a second transition arc. A third transition arc is formed between the first transition arc and the second transition arc.

[0008] Furthermore, the degree measure of the central angle corresponding to the first transition arc and the second transition arc is between 135° and 180°.

[0009] Furthermore, the radii of the first transition arc, the second transition arc, and the third transition arc are all between X and 2X, where X is the thickness of the rotor connecting line body.

[0010] Furthermore, the central angle of the third transition arc is 90°.

[0011] Secondly, the present invention provides a wound rotor, including a shaft, a rotor core, a rotor winding, a rotor winding support, a rotor connecting wire, a rotor zero ring, a rotor lead wire, and a rotor connecting wire fixing frame; wherein the rotor connecting wire adopts the rotor connecting wire structure described above in part or in whole.

[0012] The rotor winding is embedded in the rotor core and extends out of the rotor core end face along the axial direction of the shaft. The extended part is supported by the rotor winding support and is connected to the rotor zero ring and rotor lead wire through the rotor connecting line.

[0013] The rotor connecting wire fixing bracket has a "D" shaped cross section. Its vertical side is connected to the rotor winding bracket, and its arc-shaped side is fixed to the rotor connecting wire by insulating binding tape.

[0014] A rotor zero ring limiting ring is sleeved on the rotating shaft. The rotor zero ring is axially embedded in the gap between the rotor zero ring limiting ring and the rotating shaft. The gap is filled with an insulating block.

[0015] A rotor fan is also installed on the shaft, and the rotor fan is located to the right of the rotor lead wire; the inner circle of the rotor fan has a notch to avoid the rotor connection wire and the fixing structure on the surface of the shaft.

[0016] Furthermore, three of the rotor connecting lines are connected to the rotor zero ring, and the other three are connected to the rotor lead-out lines, with the axial lead-out directions of the two being opposite.

[0017] Furthermore, the rotor zero-ring limiting ring is a solid circular ring or a solid circular groove, or a circular ring or groove formed by segmented circular arcs. Specifically, the rotor zero-ring limiting ring can be a circular ring additionally mounted on the rotor winding support, or it can be a groove machined from the rotor winding support.

[0018] Furthermore, the rotor connecting wire fixing bracket is welded and fixed to the end face of the rotor winding bracket, and the rotor connecting wire fixing bracket is made of round steel or flat steel.

[0019] Furthermore, the rotor connection wire fixing frame is also provided with a special-shaped reinforcing support frame to enhance the rigidity of the rotor connection wire fixing frame, so that when the rotor connection wire is subjected to the same centrifugal force during the operation of the generator, it will produce less deformation or displacement.

[0020] Furthermore, in order to achieve a lightweight design for the rotor winding support as a whole, finite element simulation software was used to analyze and reduce the weight of the traditional "quasi-right triangle" reinforcing support frame. The part with less stress was removed, and finally a special-shaped reinforcing support structure with a similar oblique "I" shape was formed. The weight of this special-shaped reinforcing support structure was reduced by 50% compared to before the lightweighting, but the support strength was fully able to meet the support strength requirements.

[0021] Thirdly, the present invention also provides a wind turbine generator, including a wound rotor as described in part or all of the above. Because the axial distance from the rotor fan to the rotor core and rotor windings is shortened, this wind turbine generator improves the utilization rate of the internal space of the generator while also improving the temperature rise performance of the generator rotor.

[0022] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: by improving the rotor connecting wire fixing frame, rotor zero ring, reinforcing support frame, and rotor connecting wire arc bending structure, a wound rotor with an integrated rotor connecting wire structure is formed. After installation, a life test under harsh working conditions is conducted, and the wound rotor has higher reliability and better mechanical performance.

[0023] Regarding this wind turbine, the improved compact structure of the rotor fan shortens the axial distance from the rotor fan to the rotor core and rotor windings, thereby improving the space utilization inside the generator and also improving the temperature rise performance of the generator rotor. Attached Figure Description

[0024] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the existing rotor connection line structure;

[0027] Figure 2 A schematic diagram of the rotor connection line structure provided by the present invention;

[0028] Figure 3 Here is a structural diagram of an existing wound rotor;

[0029] Figure 4 The structural diagram of the wound rotor provided by the present invention;

[0030] Figure 5 The structural diagram of the rotor winding support provided by the present invention;

[0031] Figure 6 The diagram shows the structure of the irregular-shaped reinforcing support frame before and after lightweighting provided by the present invention.

[0032] Figure 7 The structural diagram of the rotor fan provided by the present invention.

[0033] The components are: 1. Rotor winding; 2. Rotor winding support; 3. Rotor connecting wire fixing frame; 4. Irregular reinforcement support frame; 5. Rotor connecting wire; 6. Insulating binding tape; 7. Bend of rotor connecting wire; 8. Rotor fan; 9. Rotor lead wire; 10. Rotor core; 11. Shaft; 12. Rotor zero ring limiting ring; 13. Rotor zero ring; 14. First connecting part; 15. Torsional connecting part; 16. Second connecting part; 17. Arc-shaped connecting part; 18. Third connecting part; 19. Notch. Detailed Implementation

[0034] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of structures consistent with some aspects of the invention as detailed in the appended claims.

[0035] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0036] Example 1

[0037] See Figure 2 As shown, this embodiment provides a doubly fed wind turbine rotor connection wire structure, including an integrally formed rotor connection wire body. The rotor connection wire body includes a first connection portion 14 connected to the rotor winding 1. Below the first connection portion 14, a torsion connection portion 15, a second connection portion 16 connected to the end face of the rotor winding support 2, and an arc-shaped connection portion 17 for reducing stress at the bending point of the rotor connection wire body are distributed in sequence. The arc-shaped connection portion 17 is connected to a horizontal third connection portion 18. The connection between the second connection portion 16 and the arc-shaped connection portion 17 forms a first transition arc, and the connection between the arc-shaped connection portion 17 and the horizontal third connection portion 18 forms a second transition arc. A third transition arc is formed between the first transition arc and the second transition arc.

[0038] Furthermore, the twisted connection 15 is twisted to better facilitate the connection between the rotor connecting wire body and the rotor winding 1 and rotor lead wire 9. Specifically, if the rotor connecting wire body is bent directly downwards in the direction of its connection to the end of the rotor winding 1 without the "twisted" twist, the thickness at the bend will inevitably be much greater than its width. On the one hand, this will occupy more space in the radial and axial directions. On the other hand, if it is bent with the aforementioned cross-section (the cross-section without twisting), the welding area between the rotor connecting wire body and the rotor lead wire 9 will be reduced, and insulation will be more difficult to perform. If the cross-section of the rotor lead wire 9 is also made vertical to ensure the welding area and insulation process, it will occupy more space inside the shaft hole and will also reduce the reliability of insulation.

[0039] Furthermore, the central angle α corresponding to the first transition arc and the central angle β corresponding to the second transition arc are both between 135° and 180°. Specifically, the degree of central angle α depends on the distance from the left side of the rotor connecting line body to the rotor support on the core side, and the degree of central angle β depends on the distance from the bottom of the rotor connecting line body to the rotating shaft 11.

[0040] Furthermore, the radii of the first transition arc, the second transition arc, and the third transition arc are all between X and 2X, where X is the thickness of the rotor connecting line body.

[0041] Preferably, the radius of each of the first transition arc, the second transition arc, and the third transition arc is 1.5X, where X is the thickness of the rotor connecting wire body.

[0042] Furthermore, the central angle of the third transition arc is 90°.

[0043] Specifically, the rotor connecting line body has optimized the large arc structure at the bend, changing the original single bend to a three-bend structure of "reverse bend - large arc bend - forward bend". Without taking up extra space, the stress concentration at the 5th bend of the rotor connecting line is minimized, improving its stress performance in the generator rotor and enhancing its overall reliability.

[0044] This rotor connecting line structure, through a three-bending design of "reverse bending - large arc bending - forward bending," can increase the length of the bending point 7 of the rotor connecting line while maintaining the same bending radius. The longer the bending point 7, the smaller the strain under the same stress. This is achieved by modifying the existing structure (…). Figure 1 The length of the arc of the bend in the structure of the present invention () Figure 2 By comparing the arc lengths of the bends in the two structures, the ratio of the arc lengths is 23.5 / 38. It can be seen that the strain at the bend of the rotor connecting line 7 in this invention is reduced compared to the strain at the bend in the existing structure.

[0045] Example 2

[0046] Based on Example 1, this example provides a wound rotor, see [link to example]. Figure 4 It includes a rotating shaft 11, a rotor core 10, a rotor winding 1, a rotor winding support 2, a rotor connecting wire 5, a rotor zero ring 13, a rotor lead wire 9, and a rotor connecting wire fixing frame 3; the rotor connecting wire 5 adopts the rotor connecting wire structure as described above;

[0047] The rotor winding 1 is embedded in the rotor core 10 and extends out of the end face of the rotor core 10 along the axial direction of the shaft 11. The extended part is supported by the rotor winding bracket 2. The extended part is connected to the rotor zero ring 13 and the rotor lead wire 9 through the rotor connecting wire 5. The rotor winding bracket 2 is connected to the shaft 11 by an interference fit through its inner circle. The rotor connecting wire fixing frame 3 and its special-shaped reinforcing support frame 4 are both part of the rotor winding bracket 2.

[0048] The rotor connecting wire fixing bracket 3 has a "D" shaped cross section. Its vertical side is connected to the rotor winding bracket 2, and its arc-shaped side (closer to the rotor connecting wire side) is fixed to the vertical part of the rotor connecting wire 5 by insulating binding tape 6. The arc part is conducive to the binding and fixing of the insulating binding tape 6. Due to the closed cross section of the "D" shaped structure, the risk of the insulating binding tape 6 detaching from the rotor connecting wire fixing bracket 3 when the rotor connecting wire 5 is subjected to strong centrifugal force is avoided.

[0049] A rotor zero ring limiting ring 12 is sleeved on the rotating shaft 11, and the rotor zero ring 13 is axially embedded in the gap between the rotor zero ring limiting ring 12 and the rotating shaft 11, and the gap is filled with an insulating block.

[0050] A rotor fan 8 is also mounted on the rotating shaft 11, and the rotor fan 8 is located to the right of the rotor lead-out line 9; the inner circle of the rotor fan 8 has a notch 19 for avoiding the rotor connecting line 5 and the surface fixing structure of the rotating shaft 11 (see Figure 7 ).

[0051] Furthermore, three of the rotor connecting lines 5 are connected to the rotor zero ring 13, and the other three are connected to the rotor lead-out line 9, with their axial lead-out directions being opposite.

[0052] Furthermore, the rotor zero ring limiting ring 12 is a complete circular ring or a complete circular groove, or a circular ring or a circular groove formed by segmented circular arcs.

[0053] Specifically, in the existing rotor structure, the rotor zero ring 13 and the rotor lead wire 9 have the same lead-out direction relative to the rotor connecting wire 5. Specifically, three rotor connecting wires 5 are connected to the rotor zero ring 13, with the rotor zero ring 13 axially close to the rotor connecting wire 5. The other three rotor connecting wires 5 are connected to the rotor lead wire 9, with their connection positions axially located outside the rotor zero ring 13. However, in the rotor structure provided by the invention, the lead-out directions of the rotor zero ring 13 and the rotor lead wire 9 relative to the rotor connecting wire 5 are opposite. Specifically, the rotor zero ring 13 is axially embedded in the gap between the rotor zero ring limiting ring 12 (or rotor zero ring limiting groove) and the rotating shaft 11. The gap between the rotor zero ring 13 and the rotor zero ring limiting ring 12 (or rotor zero ring limiting groove) and the rotor connecting wire 5 is filled with an insulating block. The rotor zero ring 13 fixing structure, after vacuum pressure impregnation and drying, can achieve higher reliability and operational stability compared to the existing wound rotor zero ring fixing structure. Even if the rotor zero ring 13 deforms under extreme working conditions due to centrifugal force, the deformation of the rotor zero ring 13 will be very limited under the restriction of the rotor zero ring limiting ring 12 (or rotor zero ring limiting groove), so that it will not cause cracks or even breakage.

[0054] Furthermore, the rotor connection wire fixing frame 3 is also provided with an irregularly shaped reinforcing support frame 4.

[0055] Specifically, to improve the mechanical performance (including rigidity) of the rotor winding 1 (coil) and rotor connecting wire 5 under strong centrifugal force during high-speed rotor rotation and rapid speed changes after the rotor connecting wire fixing bracket 3 is tightly bound to the rotor connecting wire 5 and impregnated with varnish and cured, so as to prevent the rotor connecting wire 5 from being repeatedly stretched and deformed, and to better fix the rotor connecting wire 5, ensuring that the rotor connecting wire 5 will not deform or break due to changes in centrifugal force, a special-shaped reinforcing support bracket 4 is provided on the outer or inner side of the rotor connecting wire fixing bracket 3 to avoid deformation or even breakage failure under strong centrifugal force and circumferential force.

[0056] Optionally, combined Figure 5-6 As shown, the basic shape of the irregular reinforcing support frame 4 is approximately a right triangle, which can be set inside or outside the closed section (with a certain depth) of the rotor connecting wire fixing frame 3. Its structural feature is that the two right-angled sides are connected to the rotor winding support 2 and the rotor connecting wire fixing frame 3 respectively, and its thickness is approximately the same as that of the rotor connecting wire fixing frame 3. Due to the stability of a triangle, this structural design can effectively reinforce the rotor connecting wire fixing frame 3, better coping with centrifugal and circumferential forces.

[0057] Preferably, in order to achieve the design requirement of lightweight rotor winding support 2, the relevant researchers of the present invention used finite element simulation software to analyze the stress situation of the irregular reinforcement support frame 4 and reduce its weight, removing the part with less stress, and finally obtaining a structure similar to an inclined "I"-shaped irregular reinforcement support frame 4. The weight of the irregular reinforcement support frame 4 is reduced by 50% compared with the original weight reduction, but the support strength can fully meet the support strength requirements.

[0058] Furthermore, the rotor connection wire fixing bracket 3 is made of materials including but not limited to metal materials, and its manufacturing methods include but are not limited to welding, machining, casting, and 3D printing. Preferably, the rotor connection wire fixing bracket 3 is made of round steel or flat steel, which is bent and welded to the end face of the rotor winding bracket 2, which has the advantages of simple manufacturing, low cost, and good processability.

[0059] Furthermore, combined with Figure 7 As shown, to allow the right-angled portion of the inner circle of the rotor fan 8 near the rotor connecting line 5 and the rotor lead-out line 9 to avoid the space extending from the shaft hole where the rotor lead-out line 9 is located, a notch 19 is provided in the inner circle of the rotor fan 8 to avoid the rotor connecting line 5 and the surface fixing structure of the shaft 11. This design makes full use of the generator's internal space without reducing the reliability of the rotor fan 8. The avoidance portion of the rotor fan 8 can be a full circle, or it can be only avoided in the areas affected by the three rotor lead-out lines 9.

[0060] In addition, this embodiment also provides a wind turbine, particularly a doubly fed wind turbine, including a wound rotor as described in part or all of the above.

[0061] After installation, a life test was conducted on a doubly fed wind turbine (equipped with the above-mentioned wound rotor structure) under harsh operating conditions. The wound rotor showed higher reliability and better mechanical performance. At the same time, by improving the compact structure of the rear rotor fan 8, the axial distance from the rotor fan 8 to the rotor core 10 and the rotor winding 1 was shortened, thereby improving the space utilization rate inside the generator and also improving the temperature rise performance of the generator rotor.

[0062] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0063] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A wound rotor, comprising a shaft (11), a rotor core (10), a rotor winding (1), a rotor winding support (2), a rotor connecting wire (5), a rotor zero ring (13), a rotor lead wire (9), and a rotor connecting wire fixing frame (3); characterized in that, The rotor connecting wire (5) includes an integrally formed rotor connecting wire body. The rotor connecting wire body includes a first connecting part (14) connected to the rotor winding (1). Below the first connecting part (14), there are sequentially distributed a torsion connecting part (15), a second connecting part (16) connected to the end face of the rotor winding support (2), and an arc-shaped connecting part (17) for reducing the stress at the bending point of the rotor connecting wire body. The arc-shaped connecting part (17) is connected to a horizontal third connecting part (18). The connection between the second connecting part (16) and the arc-shaped connecting part (17) forms a first transition arc. The connection between the arc-shaped connecting part (17) and the horizontal third connecting part (18) forms a second transition arc. The third transition arc is between the first transition arc and the second transition arc. The rotor winding (1) is embedded in the rotor core (10) and extends out of the end face of the rotor core (10) along the axial direction of the shaft (11). The extended part is supported by the rotor winding bracket (2). The extended part is connected to the rotor zero ring (13) and the rotor lead wire (9) through the rotor connecting line (5). The rotor connecting wire fixing bracket (3) has a "D" shaped cross section. Its vertical side is connected to the rotor winding bracket (2), and its arc side is fixed to the rotor connecting wire (5) by insulating binding tape (6). A rotor zero ring limiting ring (12) is sleeved on the rotating shaft (11), and the rotor zero ring (13) is embedded axially in the gap between the rotor zero ring limiting ring (12) and the rotating shaft (11), and the gap is filled with an insulating block; A rotor fan (8) is also installed on the shaft (11), and the rotor fan (8) is located to the right of the rotor lead line (9); the inner circle of the rotor fan (8) has a notch (19) for avoiding the rotor connecting line (5) and the surface fixing structure of the shaft (11).

2. The wound rotor according to claim 1, characterized in that, Three of the rotor connecting lines (5) are connected to the rotor zero ring (13), and the other three are connected to the rotor lead line (9), with their axial lead-out directions being opposite.

3. The wound rotor according to claim 1, characterized in that, The rotor zero ring limiting ring (12) is a whole circular ring or a whole circular groove, or a circular ring or a circular groove formed by segmented circular arcs.

4. The wound rotor according to claim 1, characterized in that, The rotor connecting wire fixing bracket (3) is welded and fixed to the end face of the rotor winding bracket (2).

5. The wound rotor according to claim 1, characterized in that, The rotor connection wire fixing frame (3) is also equipped with a special-shaped reinforcing support frame (4).

6. The wound rotor according to claim 1, characterized in that, The degree measure of the central angle corresponding to the first transition arc and the second transition arc is between 135° and 180°.

7. The wound rotor according to claim 1, characterized in that, The radii of the first transition arc, the second transition arc, and the third transition arc are all between X and 2X, where X is the thickness of the rotor connecting line body.

8. The wound rotor according to claim 1, characterized in that, The central angle of the third transition arc is 90°.

9. A wind turbine generator, characterized in that, Including the wound rotor as described in any one of claims 1-8 above.

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