Stator coil, stator having the stator coil, rotating electric machine, and method for manufacturing stator coil

Abstract

The purpose of the present application is to provide a stator coil having a corner portion with less loss and fewer starting points of partial discharge. A stator coil (6) having a conductor bar (22), the stator coil comprising at its corner portion (13): a first insulating layer (23) covering the outer periphery of the conductor bar; a conductor (24) having one end electrically connected to the conductor bar at the front end side of the corner portion and the other end disposed on the outer surface of the first insulating layer; a first conductive layer (25) covering the outer periphery of the first insulating layer and the conductor located on the outer surface of the first insulating layer; a second insulating layer (26) covering the outer periphery of the first conductive layer; and a second conductive layer (27) covering the outer periphery of the second insulating layer.

Description

Technical Field

[0001] The present application relates to a stator coil, a stator including the stator coil, a rotating electrical machine, and a method for manufacturing the stator coil. Background Art

[0002] A rotating electric machine such as a turbine generator is composed of a rotor that generates a rotating magnetic field and a ring-shaped stator arranged on the outer peripheral side of the rotor. The stator is composed of a stator core having slots arranged in a circumferential shape and a stator coil inserted into the slots. In this rotating electric machine, an induced current is generated in the stator coil due to the rotating magnetic field of the rotor. The stator coil is composed of a straight portion inserted into the slot of the stator core and a portion that is axially exposed to the outside from the stator core and bent radially outward, and is reversed at the end. Hereinafter, the portion of the straight portion of the stator coil that is inserted into the slot is referred to as the slot portion, the portion that is axially exposed to the outside from the stator core and extends radially outward is referred to as the coil end, and the bent portion connecting the slot portion and the coil end is referred to as the corner portion.

[0003] The stator coil is composed of a conductor bar formed by binding copper or other wires and an insulating layer covering the outside of the conductor bar. The insulating layer is often wound with a cirrus tape, but if there are gaps in the insulating layer, the gaps may become electrical weaknesses and cause partial discharge. In particular, the corners of the stator coil are curved, so there is a problem that gaps are easily generated between the insulating layer and the conductor bar, which is easy to cause partial discharge.

[0004] As a conventional fixed coil to address this problem, a stator coil has been disclosed, which includes a laminated tape having a double-layer structure consisting of an insulating layer and a conductive layer, which is wound around a conductor bar with the insulating layer placed inside. The portion of the conductor bar exposed at a corner and the conductive layer of the laminated tape are electrically connected via a conductor, and a main insulating layer is provided on the periphery of the laminated tape and the conductor.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Publication No. 2013-505699 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] In the conventional stator coil, the conductor bar and the conductive layer of the laminated tape are electrically connected through the conductor, so the occurrence of partial discharge at the corner can be suppressed. However, since a laminated tape with a double-layer structure consisting of an insulating layer and a conductive layer is used, the conductive layer spirally covers the periphery of the conductor bar, and the charging current flows through the spiral current path, resulting in greater loss. In addition, gaps are easily formed at the edge of the conductor, which may become the starting point of partial discharge.

[0010] The present application is made to solve the above-mentioned problems, and its object is to provide a stator coil having corner portions with small losses and few partial discharge starting points.

[0011] Technical means for solving technical problems

[0012] The stator coil of the present application is a stator coil having a conductor bar, and having a first insulating layer covering the outer circumference of the conductor bar at a corner portion; a front end portion electrically connected to the conductor bar at the front end side of the corner portion, and another front end portion of a conductor arranged on the outer surface of the first insulating layer; a first conductive layer covering the outer circumference of the first insulating layer and the conductor located on the outer surface of the first insulating layer; a second insulating layer covering the outer circumference of the first conductive layer; and a second conductive layer covering the outer circumference of the second insulating layer.

[0013] Effects of the Invention

[0014] The stator coil of the present application includes a conductor having a front end portion electrically connected to a conductor rod at the front end side of a corner portion and another front end portion arranged on the outer surface of a first insulating layer, and a first conductive layer covering the outer periphery of the first insulating layer and the conductor located on the outer surface of the first insulating layer, thereby having a corner portion with low loss and few local discharge starting points. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic cross-sectional view of the rotating electrical machine according to the first embodiment.

[0016] Figure 2 This is a schematic diagram of the stator coil according to the first embodiment.

[0017] Figure 3 This is a perspective view of the stator coil according to the first embodiment.

[0018] Figure 4 This is a schematic diagram for explaining the manufacturing process of the stator coil according to the first embodiment.

[0019] Figure 5 This is a schematic diagram for explaining the manufacturing process of the stator coil according to the first embodiment.

[0020] Figure 6 This is a schematic diagram for explaining the manufacturing process of the stator coil according to the first embodiment.

[0021] Figure 7 This is a schematic diagram for explaining the manufacturing process of the stator coil according to the first embodiment.

[0022] Figure 8 This is a schematic diagram for explaining the manufacturing process of the stator coil according to the first embodiment. DETAILED DESCRIPTION

[0023] Hereinafter, an electronic coil, a stator, and a rotating electrical machine according to an embodiment of the present application will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals in the drawings indicate the same or corresponding parts.

[0024] Implementation method 1.

[0025] Figure 1 2 is a schematic cross-sectional view of a rotating electrical machine according to Embodiment 1. The rotating electrical machine of this embodiment is, for example, a turbine generator. Figure 1 As shown in FIG. 1 , the rotary electric machine 1 is composed of a rotor 2 that generates a rotating magnetic field and a ring-shaped stator 3 provided on the outer peripheral side of the rotor 2. The stator 3 is composed of a stator core 5 having slots 4 arranged in a circumferential shape and a stator coil 6 inserted into the slots 4. The rotor 2 is provided on the inner peripheral side of the stator 3 in a manner that is freely rotatable relative to the stator 3. In the rotary electric machine 1, an induced current is generated in the stator coil 6 due to the rotating magnetic field of the rotor 2.

[0026] Figure 2 is a schematic diagram of the stator coil 6. Figure 2 As shown. The stator coil 6 is composed of a slot portion 11 and a coil end portion 12. The slot portion 11 is a part of the straight straight portion 10 and is inserted into the slot 4 of the stator core 5. The coil end portion 12 is exposed to the outside from the stator core 5 in the axial direction and is bent radially outward. The stator coil 6 is reversed at the end of the coil end portion 12. The bent portion from the slot portion 11 to the coil end portion 12 is called a corner portion 13. The position where the insulating layer, conductive layer, etc. described later are formed is the position of the corner portion 13.

[0027] Figure 3 It is a perspective view of a corner portion of the stator coil 6 . Figure 3 In the figure, the left side is the coil end side of the corner portion, that is, the front end side of the corner portion. Figure 3 In the figure, the corner portion is actually curved, but in order to explain the structure of the corner portion, it is illustrated in a non-curved state.

[0028] The stator coil 6 includes a conductor bar 22 formed by bundling conductor wires 21 of copper or the like. The conductor wire 21 is a copper wire having a rectangular cross section and is coated with an insulating coating such as varnish. The conductor bar 22 is formed, for example, by bundling the conductor wires 21 into 8 rows in the longitudinal direction and 2 rows in the transverse direction. At the corner, the outer periphery of the conductor bar 22 is covered with a first insulating layer 23 except for the coil end side of the corner. The first insulating layer 23 is formed, for example, by spirally winding a mica tape around the conductor bar 22. There is a portion not covered by the first insulating layer 23 on the coil end side of the corner of the conductor bar 22, and one end of the conductor 24 is electrically connected to the uppermost conductor wire 21 of the conductor bar 22 in the longitudinal direction at this portion. The insulating coating of the conductor 21 is removed at the portion where the conductor 21 contacts the conductor 24. The conductor 24 is formed, for example, of a metal tape or a metal tape having an adhesive layer. In addition, the other end of the conductor 24 is provided on the outer surface of the first insulating layer 23. In addition, the conductor 24 is preferably connected to only one conductor wire 21 of the conductor bar 22. This is because it is undesirable that the wires 21 are electrically connected to each other via the conductor 24. Therefore, the width of the conductor 24 is preferably equal to or smaller than the width of the wire 21.

[0029] The outer periphery of the first insulating layer 23 and the conductor 24 located on the outer surface of the first insulating layer 23 are covered by the first conductive layer 25. In addition, the outer periphery of the first conductive layer 25 is covered by the second insulating layer 26. In addition, the outer periphery of the second insulating layer 26 is covered by the second conductive layer 27. The first conductive layer 25 and the second conductive layer 27 are formed by winding a conductive tape, for example. The conductive tape is obtained by dispersing conductive carbon particles in a base material such as polyester or glass. In addition, the second insulating layer 26 is formed by spirally winding a mica tape, for example. In addition, Figure 3 , the second insulating layer 26 and the second conductive layer 27 are only partially shown in order to more easily illustrate the structure, but in fact, the second insulating layer 26 covers the entire coil end, and the second conductive layer 27 covers the range including the groove portion 11 and the corner portion 13.

[0030] The first insulating layer 23 and the second insulating layer 26 are both formed by winding a mica tape. In addition, the first conductive layer 25 and the second conductive layer 27 are both formed by winding a conductive tape, for example. The surface resistivity of these conductive layers is preferably 10 2 Ω / □ to 10 5 The range is Ω / □.

[0031] Next, a method for manufacturing the stator coil according to the present embodiment will be described.

[0032] Figures 4 to 8 Schematic diagram for explaining the manufacturing process of the stator coil. Figure 4As shown in the figure, a conductor bar 22 is prepared in which a conductor wire 21 having a rectangular cross section is bundled in 8 rows in the longitudinal direction and 2 rows in the transverse direction. The conductor wire 21 is covered with a lacquer insulation coating. A first insulating layer 23 is formed on the outer periphery of the conductor bar 22. The first insulating layer 23 is formed by spirally winding a mica tape around the conductor bar 22. The first insulating layer 23 is not formed on the coil end side of the corner portion of the conductor bar 22, and a portion of the conductor wire 21 is left exposed.

[0033] Then, if Figure 5 As shown in FIG. 1 , the conductor 24 is electrically connected to the uppermost wire 21 in the longitudinal direction of the conductor bar 22. At this time, the insulating coating of the wire 21 at the portion where the uppermost wire 21 contacts the conductor 24 is removed in advance so that the conductor 24 and the conductor bar 22 can be reliably electrically connected. The conductor 24 is, for example, a metal tape having an adhesive layer, and is bonded to the conductor bar 22 and the first insulating layer 23. In addition, the end of the conductor 24 on the side opposite to the side connected to the conductor bar 22 is arranged on the outer surface of the first insulating layer 23.

[0034] Then, if Figure 6 As shown, the first conductive layer 25 covers the outer periphery of the first insulating layer 23 and the conductor 24. At this time, the first conductive layer 25 is formed to cover only the outer periphery of the first insulating layer 23 and the conductor 24 located on the outer surface of the first insulating layer 23, and does not cover the portion of the conductor 24 bonded to the conductor bar 22. The first conductive layer 25 is formed by spirally winding a conductive tape.

[0035] Then, if Figure 7 As shown in FIG. 1 , the outer periphery of the first conductive layer 25 is covered by the second insulating layer 26. The second insulating layer 26 is formed by spirally winding a mica tape. Figure 7 , the first insulating layer 23, the conductor 24, the first conductive layer 25, etc. formed under the second insulating layer 26 are shown to be exposed, but in fact, the second insulating layer 26 covers the entire coil end.

[0036] Finally, if Figure 8 As shown in FIG. 1 , the outer periphery of the second insulating layer 26 is covered by the second conductive layer 27. The second conductive layer 27 is formed by spirally winding a conductive tape. Figure 8 , the first insulating layer 23, the conductor 24, the first conductive layer 25, the second insulating layer 26, etc. formed under the second conductive layer 27 are shown to be exposed, but in fact, the second conductive layer 27 covers the range including the corner portion.

[0037] In the stator coil thus constructed, since the conductor bar and the first conductive layer are electrically connected at the corner portion through the conductor, it is possible to suppress the occurrence of partial discharge in the portion surrounded by the conductor bar and the first conductive layer. In addition, since the first conductive layer does not constitute a spiral current path, the charging current does not flow in a spiral shape. In addition, since the first conductive layer is formed on the periphery of the conductor, even if a gap is formed in the edge portion of the conductor, it will not become the starting point of partial discharge because it is surrounded by the conductor bar and the first conductive layer of the same potential.

[0038] This application describes various embodiments, but various features, forms, and functions described in one or more embodiments are not limited to application in specific embodiments and can be applied to the embodiments alone or in various combinations.

[0039] Therefore, numerous modifications not shown in the examples are conceivable within the technical scope disclosed in the present application, including, for example, modification, addition or omission of at least one component, and extraction of at least one component and combination with components of other embodiments.

[0040] Description of symbols

[0041] 1 Rotating motor

[0042] 2 Rotors

[0043] 3. Stator

[0044] 4 slots

[0045] 5. Stator core

[0046] 6 Stator coil

[0047] 10 Straight line

[0048] 11 slots

[0049] 12 Coil end

[0050] 13 Corner

[0051] 21 wires

[0052] 22 conductor rods

[0053] 23 first insulation layer

[0054] 24 Conductors

[0055] 25 first conductive layer

[0056] 26 Second insulation layer

[0057] 27 second conductive layer.

Claims

1. A stator coil having a conductor bar, characterized in that: The stator coil comprises at its corner portion: a first insulating layer covering the outer circumference of the conductor bar only on the groove portion side; a conductor having one end electrically connected to the conductor bar on the coil end side of the corner portion and the other end disposed on the outer surface of the first insulating layer on the groove side of the corner portion; a first conductive layer, the first conductive layer covering the outer periphery of the first insulating layer and the conductor located on the outer surface of the first insulating layer, and not covering a portion of the conductor electrically connected to the conductor bar; a second insulating layer covering an outer periphery of the first conductive layer; and a second conductive layer, the second conductive layer covering the outer periphery of the second insulating layer, The first conductive layer does not form a spiral current path.

2. The stator coil according to claim 1, characterized in that: The surface resistivity of the first conductive layer and the surface resistivity of the second conductive layer are within 10 2 Ω / □ to 10 5 The range is Ω / □.

3. The stator coil according to claim 1 or 2, characterized in that: The conductor is a metal tape having an adhesive layer.

4. The stator coil according to any one of claims 1 to 3, characterized in that: The conductor bar is formed by bundling wires with rectangular cross-sections. The electrical conductor is connected to only one of the wires.

5. The stator coil according to claim 4, characterized in that: The width of the electrical conductor is smaller than the width of the conductive line.

6. A stator, characterized in that: include: An annular stator core having slots arranged in a circumferential shape; as well as The stator coil according to any one of claims 1 to 5 inserted into the slot.

7. A rotating electrical machine, characterized in that: include: The stator according to claim 6; as well as A rotor is provided on the inner circumference side of the stator so as to be rotatable relative to the stator.

8. A method for manufacturing a stator coil, characterized in that: include: A step of covering the outer circumference of the conductor bar only on the groove side with a first insulating layer; The step of electrically connecting one end of a conductor to the conductor bar at the coil end side of the corner portion of the conductor bar, and arranging the other end of the conductor on the outer surface of the first insulating layer at the groove side of the corner portion; A step of covering the outer periphery of the first insulating layer and the conductor located on the outer surface of the first insulating layer with a first conductive layer, but not covering a portion of the conductor electrically connected to the conductor bar; A step of covering the outer periphery of the first conductive layer with a second insulating layer; as well as a step of covering the outer periphery of the second insulating layer with a second conductive layer, The first conductive layer does not form a spiral current path.

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