JP2001525652A - Rotating electric machine with magnetic core - Google Patents

Abstract

(57) [Summary] The present invention relates to a rotating electric machine having a magnetic core (1). The core (1) is provided with a groove (2) for winding. According to the invention, the winding comprises a high voltage conductor. During at least one complete winding turn, the winding is provided with means for essentially confining its electric field. According to the invention, the winding part in one groove (2) is circumferentially offset.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a rotating electric machine of the kind set forth in the preamble of claim 1.

[0002] The rotating electric machine referred to in this context includes a synchronous machine which is substantially used as a generator for connection to a distribution and transmission network, commonly called a power network. The synchronous machine is also used as a motor for phase compensation and voltage control, and in that case as a mechanically idling machine. This technical field also covers ordinary asynchronous machines, double fed machines.
chines), AC machine, asynchronous converter casca
des), external pole machines and synchronous flux machines
lux machines). Although these machines are intended to be used at high voltages, high voltage here means primarily voltages above 10 KV. One typical operating range of such a rotating machine is 36-800 kV, preferably 72 kV.
. 5 to 800 kV.

[0003] Rotating electric machines are conventionally designed for voltages in the range of 6-30 kilovolts,
0 kV was generally considered the upper limit. In the case of a generator, this means that the generator must be connected to the power network via a transformer that steps up the voltage to the voltage level of the power network, which is generally in the range of 130-400 kV. Means that

[0004] Over the years, various attempts have been made to develop special synchronous machines, preferably generators, for high voltages. Examples of such attempts are, inter alia, "Electr
ical World ", Oct. 15, 1932, pp. 524-525; Elekt
Rotechnika (No. 1), 1970, page 6-8, "Water and Oil Cooled Turbine Generator TVM-300", and patent publication US 4,424.
, 244 and SU 95369.

[0005] However, none of these attempts have been successful and have not resulted in commercially available products. However, it has been found that high voltage insulated conductors of the same design as the power transmission wires (eg so-called cross-linked polyethylene wires) can be used as stator windings in rotating electrical machines. Such wires have, among other things, an outer semiconductive layer by which the outer potential of the wire is defined. In this way, the wire traps the electric field inside the winding. In this way, the voltage of the machine can be raised to a level that can be directly connected to the power network without an intermediate transformer. Thus, a very important effect is achieved, for example, that the conventional transformer can be eliminated.

[0006] The insulated conductors or high-voltage wires used in the present invention are, as mentioned above, flexible and PCT application SE97 / 00874 (WO97 / WO97 / 98).
45919) and SE 97/00875 (WO 97/45847). Further description of insulated conductors or wires can be found in PCT application SE 97/00901 (WO 97/45918), SE 97/00
902 (WO 97/45930) and SE 97/00903 (WO 97/45)
931).

The magnetic core in a machine usually consists of a stator surrounding the rotor of the machine. In such a machine, the windings passing through the core extend through axial grooves in the stator. These grooves are generally radial, meaning that the distance between the grooves increases with the distance from the inner lateral region of the stator. This means that the magnetic flux density decreases outside the stator. Therefore, in the outer part of the groove, there is an excess of core material, generally consisting of laminated steel sheets. This makes the machine unnecessarily large and heavy.

[0008] The latter is not a major problem in small machines, but this problem is accentuated as machine dimensions increase.

According to the invention, the windings are in the form of high voltage conductors, which means that the larger the number of winding parts in each groove, the larger the machine. are doing. Since the conductor of the present invention is provided with a means for confining an electric field as described in the characterizing part of claim 1, it has become possible to design a machine for high voltage.

[0010] The problem that a significant portion of the core material is redundant, resulting in an unnecessary increase in the volume and weight of the machine, is therefore very particularly important for such machines designed for high voltages. is there.

In light of the above facts, it is an object of the present invention to achieve a machine which can or can be supplied with a high voltage directly, and thus to try to minimize the volume and weight of the machine It is in.

According to the invention, this is achieved by designing a machine of the kind described in the preamble of claim 1 to include the special features described in the characterizing part of claim 1. You.

[0013] The means for confining the electric field, and the arrangement described in the characterizing part of the claims, achieve a machine operating in the high-voltage range and thus connected to the high-voltage network without connecting to an intermediate transformer. Is done.

As described as an additional important feature, the winding sections also exhibit a circumferential deviation in relation to each other, so that between such a pair of winding sections of the winding Are reduced compared to when they only deviate radially only. Both winding sections are round and have the same diameter 2r and, for example, the distance r
Provided that they are only circumferentially offset from one another, there is room for reducing the radial distance between them by about 14%.

In the context of the present application, the expression “winding part” means the area between the axial ends of the wires of the stator core in the half-turn part of the winding.

Another advantage is that the lateral deflection provides greater flexibility in the placement of the winding sections within the core, so the windings can be based on mechanical, magnetic, thermal and other aspects. This means that the possibility of optimization increases.

The winding parts in the same groove can thus be arranged more compactly with respect to one another in the radial direction. This allows the core to be made smaller,
The result is the possibility of reducing the radial extent of the groove, so that the weight is reduced. This results in material savings and advantages during manufacture and transport as well as during operation and maintenance.

The possibility of radially packing the windings is provided by the lateral displacement of the winding sections, but the larger the space available due to the lateral displacement, the greater the radial displacement. Used for compression. According to a preferred embodiment of the present invention, therefore, a set of adjacently disposed winding portions is such that the radially innermost portion of the outer winding portion is the outermost of the inner winding portion. It is arranged to be located radially inward of the part.

In a preferred embodiment, the excursion increases as the winding portion is positioned more outward. This takes advantage of the fact that more and more space is available on the outside, when tightly packed, the core material is not required and can be used to increase circumferential deviation, This means that the volume can be reduced to a corresponding extent.

In a preferred embodiment of the invention, the geometry of the groove is such that the groove has a lateral component, which is suitable for the groove shape for a laterally offset winding part. A suitable fit.

In a preferred embodiment, the directional component is increased because the groove is curved laterally. This contributes to the effective utilization of the outwardly increasing space utilized between the core materials.

The optimal condition in this regard is that each groove bends over its entire length,
All grooves are curved in the same direction, which constitutes an additional preferred embodiment of the present invention. From a space utilization point of view, all grooves are parallel in an ideal design.

The present invention can be realized by designing a groove to have a groove whose width increases radially outward or a groove having a constant width. In both cases,
These grooves can advantageously be of the "bicycle chain" type, i.e. of a type having alternating wide and narrow sections.

According to a preferred embodiment, the conductor with the electric field confinement means is flexible between at least one complete winding turn, enabling an advantageous winding process from a manufacturing technology point of view. I do.

According to a preferred embodiment, the electric field confinement means includes an inner semiconductive layer surrounding the conductor, an insulating layer surrounding the inner semiconductive layer, and an outer semiconductive layer surrounding the insulating layer. Having.

In a particularly preferred embodiment, the layers are bonded together and have substantially the same coefficient of thermal expansion, thereby exposing them to mechanical and thermal stresses that occur during operation. It is properly assured that these layers maintain their function when they are used.

[0027] The above and other advantageous embodiments of the machine according to the invention are described in the dependent claims which refer to claim 1.

The present invention will be described in more detail by the detailed description of preferred embodiments thereof with reference to the accompanying drawings.

FIG. 1 is a principle diagram showing how a stator of a conventional electric rotating machine is generally designed. The core 101 made of laminated steel plates is provided with a groove 102 for stator winding. A trapezoidal section 104 having a trapezoidal cross section, hereinafter referred to as a stator tooth, is formed between each set of grooves. The distance d0 in the stator inner lateral region 103 between the pair of grooves 102 is determined by the amount of core material required for the resulting magnetic flux density. In a completely radially extending groove having a constant groove width, as shown in the figure, the width of the intermediate stator teeth increases outward to provide excess core material. This shaded portion of the tooth thus represents the "unnecessary" core material, while the required core material is located between a pair of dashed lines. Where the discussion in this context should be considered a basic representation, in different practical applications, modifications to the basic representation may appear depending on different embodiments of the machine stator, The fundamental aspect of the "usability" of a material is more or less important. The basic concept of the present invention is to remove "unwanted" core material by various methods so that the weight and volume of the core are reduced.

FIG. 2 shows a first preferred embodiment of the basic design of the stator according to the concept of the invention, wherein the core 1 is a stator 1 surrounding a rotor (not shown). It is. The core 1 is provided with a groove 2 for winding. The groove 2 is continuously curved,
All grooves 2 are curved in the same direction and are parallel. Between each pair of grooves 2, curved teeth 4 are formed in the same main shape as the grooves 2. The curved teeth each have a width d. That is, the distance between the walls of adjacent grooves is substantially constant and equal to the width d0 in the inner lateral region 3 of the stator.

The groove is of a so-called bicycle chain type, in which a wide portion and a web portion are alternately formed, and each of the wide portions accommodates an electric wire portion. When indicating that the tooth width d is substantially constant, insignificant differences arising from alternating wide portions and web portions are thus ignored.

The helical shape of the grooves 2 makes their radial extent smaller when the number of wire sections in the grooves is equal than when these grooves extend completely radially. Shaded area 102 indicates the length of the corresponding radially arranged groove, and ΔR indicates the radial reduction of the stator achieved in this way. This makes the stator smaller and lighter.

FIG. 2 shows a stator according to the invention in which the principle is optimally used, but numerous variants are possible to realize the principle. Other considerations during the manufacture, design and operation of the machine extend to several embodiments, in which the concepts of the present invention may vary in varying forms and to varying degrees between conflicting requirements. Achieved with compromise.

FIGS. 2 a and 2 b show some variations of the groove arrangement. Circles represent winding portions. In FIG. 2a, the diameter of the wire increases outward. This is also the case in FIG. 2b, but here the grooves extend in a bent pattern.

In other embodiments, each groove can be curved only in a portion of its area, bend with a varying radius, or bend in different directions with a bent shape. The grooves may also be fully or partially inclined with respect to the radial direction and not curved. The distance between the two grooves does not need to be constant.

Further, FIGS. 3 to 6 show some examples of the basic shapes of the grooves, but the present invention can be applied to all of them. These grooves are shown in their basic shape and are not curved as in the present invention. The groove 2a in FIG. 3 has a constant groove width for wire sections having the same diameter. The groove 2b in FIG. 4 has a groove width wider toward the outside for a winding having a winding part that is thicker at the end of the groove. The grooves 2c and 2d in FIGS. 5 and 6 respectively show a "bicycle chain" type, i.e. a groove with alternating wide portions and web portions, the latter function of which fixes the winding portion radially. That is. The grooves can also be designed to have an outward taper.

FIG. 7 schematically shows a state in which a pair of adjacently disposed winding portions is deviated according to the present invention, but the intention is to show the principle of the present invention.

In FIG. 7, a pair of winding portions 5 and 6 are arranged inside the groove 2 of the stator according to the present invention. Arrow A indicates the radial direction of the stator and reference numeral 106
Is how the outside of the winding section 6 is arranged when the winding section 6 is completely radially outward with respect to the inner winding section 5 inside the groove 102, i.e. conventionally. Is shown. For clarity, the winding sections are shown as touching each other, but of course, this is not always the case. However, this expression is generally correct even if it is not.

The outer winding part 6 is offset from the conventionally arranged winding 106 by a distance a across the radial direction. This excursion is caused by the conventionally arranged winding 106
In contrast, a space is provided for displacing the winding portion 6 in the radial direction by the distance b.

Assuming that the radii of the pair of winding portions are r _{1 and} r ₂ , the distance b is b = r ₁ + r ₂ − ((r ₁ + r ₂ ) ² −a ² ) ^1/2 , where r ₁ = If r ₂ = r, b can be simplified to b = 2r− (4r ² −a ² ) ^1/2 . If the lateral deviation a is a = r, the radial deviation b is b = r (2−31 ^{/ 2} ) = 0.27r, which means that in this case the outer deviation This means that about 14% of the radial space required by the winding is reduced.

Finally, FIG. 8 shows a cross section of a wire particularly suitable for use in windings in the stator of the present invention. The electric wire 6 includes at least a conductor 31 made of, for example, copper, through which a current flows, which is surrounded by the first semiconductive layer 32. Around the first semiconductive layer, for example, an insulating layer 33 made of cross-linked polyethylene is arranged,
A second semiconductive layer 34 is arranged around the insulating layer. The conductor can consist of many parts 31. These three layers are designed to adhere to each other even when the wire is bent. The wire shown is flexible and this property is maintained during its lifetime. The illustrated wires differ from conventional high-voltage wires in that the outer mechanical protective casing and the generally surrounding metal screen have been removed.

[Brief description of the drawings]

FIG. 1 is a schematic view of a stator of an electric machine according to the related art.

FIG. 2 schematically illustrates a radial portion of a stator according to a preferred embodiment of the present invention.

FIG. 2A is a diagram showing an example of a groove shape to which the present invention can be applied.

FIG. 2B is a diagram showing an example of a groove shape to which the present invention can be applied.

FIG. 3 is a diagram showing an example of a groove shape to which the present invention can be applied.

FIG. 4 is a diagram showing an example of a groove shape to which the present invention can be applied.

FIG. 5 is a diagram showing an example of a groove shape to which the present invention can be applied.

FIG. 6 is a diagram showing an example of a groove shape to which the present invention can be applied.

FIG. 7 is a principle view illustrating the concept of the present invention.

FIG. 8 is a radial cross-sectional view of a conductor of a winding according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic core (stator) 2 Groove 3 Inner lateral area 5 Winding part 6 Winding part 31 Conductor 32 Semiconductive layer 33 Insulating layer 34 Semiconductive layer 101 Core 102 Groove 103 Inner lateral area 104 Trapezoidal part 106 winding line

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IS, JP, KE, KG , KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZWF terms (reference) 5H002 AA06 AA09 AB00 AE06 5H604 AA01 BB04 BB09 BB10 BB14 CC01 CC05 CC14 DA17 PB01 PD07 5H619 AA04 BB02 PP01 PP05 PP14

Claims (17)

[Claims] A magnetic core having a central axis defining an axial direction, a radial direction and a circumferential direction.
The core (1) has a plurality of grooves (2), each of the grooves (2) defining a longitudinal direction including an axial direction component and a lateral direction including a radial direction component; The direction of the groove (2) is defined by a central plane between the walls of the groove (2), and the groove (2) has a width defined as the distance between the walls, and a plurality of windings extending in the longitudinal direction. An electric winding having wire portions (5, 6)
) Wherein at least some of the winding parts (5, 6) are arranged radially offset from one another in at least some of the grooves, the windings being adapted for high voltage A conductor (31), wherein said conductor (31) has at least one complete winding turn,
Means (32, 33, 34) for essentially confining the electric field are provided, and at least one set of adjacently disposed winding portions (5, 5) inside one groove (2). 6), wherein the rotating electric machines are circumferentially offset from each other. 2. In a set of adjacently disposed winding portions (5, 6), said outer winding portions (5, 6).
The rotating electric machine according to claim 1, characterized in that the radially innermost part of (6) is arranged radially inward of the outermost part of the inner winding part (5). 3. At least two sets of winding portions (5, 6) in said groove are circumferentially offset from one another, said offset being in a radial direction in which the winding portions (5, 6) are arranged. 3. The rotating electric machine according to claim 1, wherein: 4. The rotating electric machine according to claim 1, wherein at least some of the grooves have a circumferential directional component along at least a lateral part thereof. 5. The dynamoelectric machine according to claim 4, wherein at least some of the grooves (2) are at least partially laterally curved. 6. A dynamoelectric machine according to claim 5, wherein each groove (2) is curved along its entire lateral direction and all grooves (2) have the same radius of curvature. . 7. A dynamoelectric machine according to claim 1, wherein all the grooves are parallel in both a longitudinal direction and a transverse direction. 8. A dynamoelectric machine according to claim 1, wherein at least some of the grooves have a lateral width that increases outwardly. 9. The rotating electric machine according to claim 1, wherein at least some of the grooves have a constant width in the lateral direction. 10. The rotation according to claim 1, wherein at least some of the grooves have a portion in which a large width and a small width are alternately arranged in the lateral direction. Electric machine. 11. The method of claim 1, wherein the portion having a large width has a variable width.
The rotating electric machine according to 0. 12. The rotating electric machine according to claim 10, wherein the portions having a large width have the same width as each other. 13. The rotating electric machine according to claim 1, wherein the conductor is flexible during at least one complete winding turn. 14. The semiconductor device according to claim 1, wherein said means includes an inner semiconductive layer surrounding said conductor,
2) and an outer semiconductive layer (34) surrounding the insulating layer (33).
The rotating electric machine according to any one of claims 1 to 13, comprising: 15. The rotating electric machine according to claim 14, wherein each semiconductive layer (32, 34) essentially constitutes an equipotential surface. 16. The layer (32, 33, 34) is secured to one another throughout the winding and the semiconductive layer (32, 34) is substantially identical in thermal conductivity to the intermediate insulating layer (33). The rotating electric machine according to claim 15, wherein the rotating electric machine has a ratio. 17. The device according to claim 1, wherein the means are dimensioned to allow a voltage in the electrical conductor to be higher than 72 KV. Rotating electric machine.