Rotor lead structure of a high-power doubly-fed electric machine

Abstract

The application discloses a rotor lead structure of a high-power double-fed motor and relates to the technical field of motor rotor leads. In view of the existing problems, the following scheme is provided. The rotor lead structure comprises a rotating shaft installed on the high-power double-fed motor, a rotor coil and a slip ring are installed on the rotating shaft, a current collector ring is installed on the wiring end of the rotor coil, a wiring copper column is installed on the slip ring, each phase of the rotor coil comprises a coil connecting copper bar, a rotor lead cable, a slip ring connecting straight copper bar and a slip ring connecting copper sheet, the upper end of the coil connecting copper bar is a U-shaped groove, the coil is inserted into the U-shaped groove and welded, the lower end of the coil connecting copper bar is a hole plane, and the coil connecting copper bar and the rotor lead cable are connected in a copper rivet riveting mode. The application solves the technical problems that the rotor current of the high-power double-fed motor is large, the rotor cable has a large cross section but a small shaft hole diameter, the rotor cable generates serious heat in the shaft hole, and the connection between the rotor cable and the slip ring from the shaft hole is unreliable.

Description

Technical Field

[0001] This invention relates to the field of motor rotor lead technology, and more particularly to a rotor lead structure for a high-power doubly-fed motor. Background Technology

[0002] A doubly fed motor is a type of motor in which both the stator and rotor can output power to the power grid and absorb power from the power grid. Its characteristic is that the rotor's three-phase current is connected to the three-phase carbon brushes of the slip rings to realize the transmission of rotor power.

[0003] The traditional structure of rotor leads involves connecting one end of a cable to the rotor winding, passing vertically downwards through an oblique hole on the shaft to enter the shaft, laying it horizontally along the inner hole of the shaft, exiting from the end face of the shaft, bending upwards to connect to the terminal of the slip ring.

[0004] As generator power increases and rotor current increases, the cross-sectional area of ​​a single rotor cable will inevitably increase or multiple cables will be connected in parallel. However, due to the limitation of the overall shaft diameter of the transmission chain, it cannot be too large, which restricts the synchronous arrangement of thicker or more cables in the inner hole of the shaft. The smaller cable cross-sectional area will cause severe heat generation in the sealed shaft hole due to insufficient safe current carrying capacity, which will reduce the cable insulation life.

[0005] In addition, due to the limitations of the shaft diameter and its own structure, the slip ring connecting copper column of a high-power doubly-fed motor has been changed from one to two. The cable passes through the inner hole of the shaft and is connected to the terminal block at a right angle. As the shaft rotates with the cable and terminal block, the terminal block deforms under the action of centrifugal force, which puts a tension on the cable in the radial direction. When the motor runs for a long time, the reliability of the cable is greatly reduced under alternating stress and severe heat generation. The rotor lead structure is also one of the components with the highest failure rate of the doubly-fed motor. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a rotor lead structure for a high-power doubly-fed motor, which solves the technical problems of high rotor current, large rotor cable cross-sectional area but small shaft hole diameter causing severe heat generation in the rotor cable within the shaft hole, and unreliable connection between the rotor cable led out from the shaft hole and the slip ring.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A rotor lead structure for a high-power doubly-fed motor includes a rotating shaft mounted on the high-power doubly-fed motor, on which a rotor coil and a slip ring are mounted. A slip ring is mounted on the terminal of the rotor coil, and a copper terminal is mounted on the slip ring.

[0009] Each phase of the rotor coil includes a coil connecting copper busbar, a rotor lead cable, a slip ring connecting straight copper busbar, and a slip ring connecting copper sheet.

[0010] As a preferred embodiment of the present invention, the upper end of the coil connecting copper busbar is a U-shaped groove, the coil is inserted into the U-shaped groove and welded, and the lower end of the coil connecting copper busbar is a perforated plane, which is connected to the rotor lead cable by means of copper rivets.

[0011] As a preferred technical solution of the present invention, the rotating shaft is provided with a shaft hole, and after the rotor lead cable is vertically inserted into the shaft hole, it is changed to be horizontally connected to one end of the straight copper busbar of the slip ring.

[0012] As a preferred embodiment of the present invention, the other end of the slip ring connecting straight copper busbar is outside the shaft hole and connected to one end of the slip ring connecting copper plate, and the other end of the slip ring connecting copper plate is connected upward to the connecting copper post of the slip ring.

[0013] As a preferred embodiment of the present invention, the slip ring connecting copper sheet has an irregular arc structure.

[0014] As a preferred embodiment of the present invention, one end of the rotor lead cable is connected to the rotor coil, and the other end of the rotor lead cable is connected to the slip ring.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. The section from the rotor winding to the point where it enters the shaft hole still uses a cable, while the section from the inner shaft hole to the point where it extends out of the shaft hole is replaced by a single straight copper busbar instead of the original two parallel cables. Previously, high-power doubly-fed motor rotor lead cables were laid in parallel with two cables because the cross-sectional area of ​​a single cable was too large, the bending radius was long, and the assembly process was difficult. The copper post connecting the outer shaft hole to the slip ring is replaced by two sets of multi-layer irregularly shaped arc copper sheets. The single straight copper busbar in the inner shaft hole saves space and increases its cross-sectional area, thus reducing its resistance and heat loss, and greatly improving the overheating situation in the shaft hole.

[0017] 2. Compared with cables, the irregular arc copper strip can offset the tensile force caused by the deformation of the connecting copper column due to the arc structure deformation. Moreover, the irregular arc copper busbar is not affected by the size of the straight copper busbar at the front end, which can increase its cross-sectional area. While ensuring a low electrical density, it greatly improves the tensile strength at this point, and further improves the reliability of the motor. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the rotor lead structure of a high-power doubly-fed motor proposed in this invention.

[0019] Figure 2This is a schematic diagram of the rotor lead components in the rotor lead structure of a high-power doubly fed motor proposed in this invention.

[0020] Figure 3 This is a cross-sectional view of the rotor lead inside the shaft hole in the rotor lead structure of a high-power doubly fed motor proposed in this invention.

[0021] Figure 4 This is a schematic diagram of the rotor lead structure of a high-power doubly fed motor proposed in this invention, showing the connection between the slip ring and the straight copper busbar, the slip ring and the arc-shaped copper busbar, and the copper terminal of the slip ring.

[0022] In the diagram: 1. Rotor coil; 2. Coil connecting copper busbar; 3. Rotor lead cable; 4. Shaft; 5. Slip ring; 6. Collector ring; 7. Connecting copper post; 8. Slip ring connecting copper sheet; 9. Slip ring connecting straight copper busbar. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, unless otherwise stated, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," etc., indicate the orientation or state relationship based on the orientation or state relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the mechanism or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0025] Example 1, referring to Figure 1-4 A rotor lead structure for a high-power doubly-fed motor includes a rotating shaft 4 mounted on the high-power doubly-fed motor, a rotor coil 1 and a slip ring 5 mounted on the rotating shaft 4, a slip ring 6 mounted on the terminal of the rotor coil 1, and a copper terminal 7 mounted on the slip ring 5. Each phase of the rotor coil 1 includes a coil connecting copper busbar 2, a rotor lead cable 3, a slip ring connecting straight copper busbar 9 and a slip ring connecting copper sheet 8.

[0026] As a further part of the present invention, the upper end of the coil connecting copper busbar 2 is a U-shaped groove, the coil is inserted into the U-shaped groove and welded, and the lower end of the coil connecting copper busbar 2 is a perforated plane, which is connected to the rotor lead cable 3 by means of copper rivet riveting.

[0027] As a further part of the present invention, a shaft hole is provided on the rotating shaft 4. After the rotor lead cable 3 extends vertically downward into the shaft hole, it is changed to be horizontally connected to one end of the straight copper busbar 9 connected to the slip ring.

[0028] As a further part of the present invention, the other end of the slip ring connecting straight copper busbar 9 is outside the shaft hole and connected to one end of the slip ring connecting copper plate 8, and the other end of the slip ring connecting copper plate 8 is connected upward to the wiring copper post 7 of the slip ring 5.

[0029] As a further embodiment of the present invention, one end of the rotor lead cable 3 is connected to the rotor coil 1, and the other end of the rotor lead cable 3 is connected to the slip ring 5.

[0030] Example 2, refer to Figure 1-4 A rotor lead structure for a high-power doubly-fed motor includes a rotating shaft 4 mounted on the high-power doubly-fed motor, a rotor coil 1 and a slip ring 5 mounted on the rotating shaft 4, a slip ring 6 mounted on the terminal of the rotor coil 1, and a copper terminal 7 mounted on the slip ring 5. Each phase of the rotor coil 1 includes a coil connecting copper busbar 2, a rotor lead cable 3, a slip ring connecting straight copper busbar 9 and a slip ring connecting copper sheet 8.

[0031] As a further part of the present invention, the upper end of the coil connecting copper busbar 2 is a U-shaped groove, the coil is inserted into the U-shaped groove and welded, and the lower end of the coil connecting copper busbar 2 is a perforated plane, which is connected to the rotor lead cable 3 by means of copper rivet riveting.

[0032] As a further part of the present invention, a shaft hole is provided on the rotating shaft 4. After the rotor lead cable 3 extends vertically downward into the shaft hole, it is changed to be horizontally connected to one end of the straight copper busbar 9 connected to the slip ring.

[0033] As a further part of the present invention, the other end of the slip ring connecting straight copper busbar 9 is outside the shaft hole and connected to one end of the slip ring connecting copper plate 8, and the other end of the slip ring connecting copper plate 8 is connected upward to the wiring copper post 7 of the slip ring 5.

[0034] As a further embodiment of the present invention, one end of the rotor lead cable 3 is connected to the rotor coil 1, and the other end of the rotor lead cable 3 is connected to the slip ring 5.

[0035] As a further improvement of the present invention, the slip ring connecting copper sheet 8 has an irregular arc structure.

[0036] In summary: This invention still uses cables from the rotor winding lead-out to the part just entering the shaft hole, but the part from the inner shaft hole to the part extending out of the shaft hole is replaced by a single straight copper busbar instead of the original two parallel cables. Previously, high-power doubly-fed motor rotor lead cables were laid in parallel with two cables because the cross-sectional area of ​​a single cable was too large, the bending radius was long, and the assembly process was difficult. However, the copper post 7 connecting from the outside of the shaft hole to the slip ring 5 is replaced by two sets of multi-layer irregular arc copper sheets. The single straight copper busbar in the inner shaft hole saves space and increases its cross-sectional area, thus reducing its resistance and heat loss, and greatly improving the overheating situation in the shaft hole.

[0037] Compared with cables, the irregular arc copper sheet can offset the tensile force caused by the deformation of the connecting copper post 7 due to the deformation of its own arc structure. Moreover, the irregular arc copper busbar is not affected by the size of the straight copper busbar at the front end, which can increase its cross-sectional area. While ensuring a low electrical density, it greatly improves the tensile strength at this point, and the reliability of the motor is further improved.

[0038] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A rotor lead structure for a high-power doubly-fed induction generator, comprising a rotating shaft (4) mounted on the high-power doubly-fed induction generator, characterized in that, The rotor coil (1) and slip ring (5) are installed on the rotating shaft (4). A collector ring (6) is installed at the terminal of the rotor coil (1), and a copper terminal (7) is installed on the slip ring (5). Each phase of the rotor coil (1) includes a coil connecting copper busbar (2), a rotor lead cable (3), a slip ring connecting straight copper busbar (9), and a slip ring connecting copper sheet (8). The upper end of the coil connecting copper busbar (2) is a U-shaped groove. The coil is inserted into the U-shaped groove and welded. The lower end of the coil connecting copper busbar (2) is a perforated plane, which is connected to the rotor lead cable (3) by means of copper rivets. The rotating shaft (4) has a shaft hole. After the rotor lead cable (3) is vertically inserted into the shaft hole, it is changed to be horizontally connected to one end of the straight copper busbar (9) of the slip ring. The other end of the slip ring connecting straight copper bus (9) is outside the shaft hole and is connected to one end of the slip ring connecting copper plate (8). The other end of the slip ring connecting copper plate (8) is connected upward to the wiring copper post (7) of the slip ring (5). The slip ring connecting copper plate (8) is an irregular arc structure. One end of the rotor lead cable (3) is connected to the rotor coil (1), and the other end of the rotor lead cable (3) is connected to the slip ring (5).

Images