EP0540958A1 - Toroidal inductance - Google Patents

Abstract

In order to be able to limit, for example, short-circuit currents of 100 kA or more in high-power converters, a toroidal inductor (1) having a plurality of turns is used, which has a plurality of segmented partial windings (2). Each partial winding (2) is in electrically conductive contact with at least one connecting element (3) in order to be able to connect adjacent partial windings (2) in series or a plurality of partial windings (2) in parallel. The partial windings (2) have an approximately identical current cross-section over their length; their width (a) is less in the inner region (4) than their width (b) at the peripheral outer edge (5). In consequence, a large number of turns and a modular inductor construction are possible, with a high mechanical strength. <IMAGE>

Description

TECHNICAL AREA

The invention is based on a toroidal throttle according to the preamble of claims 1 and 6.

STATE OF THE ART

With the preamble, the invention relates to a prior art, as is known from DE-PS 970 447. There, the winding of a toroidal choke is alternately composed of two parts, one part of which forms half a turn and the second part one and a half times. The two winding parts made of bare copper tape are connected to each other by brazing or welding. Ring-shaped ceramic upper and lower parts are used for the border.

This throttle structure requires a relatively large volume. In the event of a short circuit, the stability and mutual support of the winding parts are unsatisfactory.

From DE-OS 2 658 774 a commutation choke for converter systems made of twisted stranded wires is known, in which the non-segmented turns of the coil consist of many conductor strands which are interwoven in a tubular manner. The tubular conductor is pressed together in the shape of a rectangle in cross section. Several tubular or rectangular conductors can be arranged concentrically to one another. From the Swiss company magazine: Brown Boveri Mitt. 12 (1978), pp. 777-785, a toroidal air choke coil is known which has a medium inductance and can be loaded with a current which is highly harmonic. Such chokes are used as swinging and quenching chokes in power converters of mass transit vehicles.

Such a choke is not suitable for short-circuit currents of the order of 100 kA - 140 kA, as can occur in high-performance converters due to ignition. Such short-circuit currents can, for. B. occur when in a bridge circuit 2 belonging to the same phase unintentionally or incorrectly ignite simultaneously and thus short-circuit the intermediate circuit capacitor of a converter with DC intermediate circuit.

PRESENTATION OF THE INVENTION

The invention, as defined in claims 1 and 6, solves the problem of further developing a toroidal choke of the type mentioned at the outset in such a way that it can be used for currents of und 100 kA and has a minimal volume and small losses.

An advantage of the invention is that the segment choke can be connected in series or in parallel from a plurality of segments of a toroid or annular bead after the windings have been assembled. Relatively dimensionally stable segments of high current carrying capacity can be used, which do not have to be able to be wound. A high mechanical strength of the toroidal choke can thus be achieved. The toroidal choke is easy to assemble, while ensuring a high short-circuit strength.

A given installation volume can be better used, whereby the geometry of the toroidal choke can be reproduced very precisely. The number of turns and thus the inductance of the toroidal choke can be easily changed or set.

When using a pressure bandage or a peripheral steel ring and side pressure plates around the toroidal throttle, the copper used for the segments can be stressed up to several times its yield point.

For the segmented toroidal choke, a high fill factor with a large passage area for the magnetic field can be achieved with minimal leakage flux.

A modular choke structure is possible by choosing more or fewer turns or radially offset turns.

The chokes can be rectangular on the outside. Natural or liquid cooling with forced circulation, e.g. B. oil cooling are possible.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

einen Ausschnitt einer perspektivisch dargestellten Toroiddrossel aus vorgefertigten Teilwicklungen,

Fig. 2

einen modularen Drosselaufbau im Ausschnitt mit radial versetzt angeordneten Teilwicklungen,

Fig. 3

eine am Aussenumfang rechteckig begrenzte Toroiddrossel im Ausschnitt,

Fig. 4

eine Teilwicklung einer Toroiddrossel mit gewinkelten Verbindungselementen,

Fig. 5

ein Wicklungselement mit Mehrfachwindung,

Fig. 6

eine Winkelprofilwindung,

Fig. 7a und 7b

ein Wicklungselement aus Litze,

Fig. 8

eine Segmentdrossel in Draufsicht,

Fig. 9

einen senkrechten Schnitt durch die Segmentdrossel gemäss Fig. 8 mit Druckbandage und Spannplatten,

Fig. 10

ein Segment der Segmentdrossel gemäss Fig. 8 in perspektivischer Darstellung,

Fig. 11

eine Isolierfolie der Segmentdrossel gemäss Fig. 8 und

Fig. 12

einen Ausschnitt einer Teilwicklung in flächenhafter Ausbildung.

The invention is explained below using exemplary embodiments. Show it:

Fig. 1

a section of a toroidal choke made of prefabricated partial windings, shown in perspective,

Fig. 2

a modular choke structure in the cutout with radially staggered partial windings,

Fig. 3

a toroidal throttle with a rectangular border on the outer circumference,

Fig. 4

a partial winding of a toroidal choke with angled connecting elements,

Fig. 5

a winding element with multiple turns,

Fig. 6

an angle profile turn,

7a and 7b

a winding element made of stranded wire,

Fig. 8

a segment choke in plan view,

Fig. 9

8 a vertical section through the segment throttle according to FIG. 8 with pressure bandage and clamping plates,

Fig. 10

8 is a perspective illustration of a segment of the segment throttle according to FIG. 8,

Fig. 11

an insulating film of the segment choke according to FIGS. 8 and

Fig. 12

a section of a partial winding in extensive training.

WAYS OF CARRYING OUT THE INVENTION

In Fig. 1, (1) denotes a partial toroidal choke, which is constructed from a plurality of U-shaped winding elements or segmented partial windings (2). The partial windings (2) are arranged in a ring around a central, cylindrical recess (6) and each have a lower leg (2a) and an upper leg (2b). At the inner edge (4), the partial windings (2) have a width a that is smaller than a width b on their outer edge (5). The two legs (2a, 2b) have a height c near the inner edge (4) which is greater than their height d on the outer edge (5). The widths a and b are dimensioned so that the available volume for the toroidal choke (1) is used well. The associated heights c and d are dimensioned such that a current cross-sectional area through each partial winding (2) is the same or does not deviate from an average or desired current cross-sectional area by more than 30%, preferably not more than 10%. On the outer edge (5) of the upper leg (2a) of a partial winding (2) each with the outer edge (5) of the lower leg (2a) of an adjacent partial winding (2) by means of an electrical connecting element (3) made of copper z. B. electrically connected by soldering. By Such electrical connecting elements (3) connect the individual partial windings (2) to form a single toroidal turn or connect them in series. The toroidal choke (1) has 360 / β partial windings, where β denotes a segment pitch angle measured in degrees.

Fig. 2 shows a section around a central recess (6) of several circularly arranged, separate segmented partial windings, with adjacent partial windings (7-9) having a different length (1) in the radial direction. Such a staggering enables a high element density or number of turns of the toroidal choke (1) to be achieved. In this way, a high fill factor can be obtained with a large conductor cross section.

Fig. 3 shows a detail of a toroidal choke (1) with a plurality of partial windings (10) which have different lengths in the radial direction and rectangular boundaries along the perpendicular surfaces (11, 12) on the outer edge. In this way, the toroidal throttle (1) can be adapted to a predetermined volume. It goes without saying that the external boundary also z. B. 5-sided, 6-sided, etc. could be selected.

Fig. 4 shows a U-shaped partial winding (13) with 2 symmetrical, angled connecting elements (13a, 13b), which have an inside angle (α) in the range of 90 ° - 150 °, preferably in the range of 100 ° - 130 ° lock in. Such partial windings (13) can, for. B. made of aluminum or copper, made as flat sheet metal cuts and used in multiple layers if necessary.

Fig. 5 shows a partial winding or a winding element (14) with several serpentine windings arranged one above the other, which are mutually insulated by means of electrically insulating spacers or insulators (15). The reference number (16) denotes one Connection area and the reference number (17) an externally folded and insulated connection end.

Fig. 6 shows a partial winding (18) in an angle profile with chamfered inner corners (18a) and enlarged outer surfaces, which are obtained by bending from a sheet metal cut. (19) denotes connection areas for a screw connection, not shown. With similar geometry, massive partial windings (18) z. B. cast, pressed or deep drawn.

Fig. 7a shows a partial winding (20) made of stranded wire, which is cast with a thermal resin to form a compact, dimensionally stable element. With (21) a connection profile is designated. Fig. 7b shows a sectional view along a line A-A in Fig. 7a. Instead of stranded wire, such a partial winding (20) can also be produced from individual sheet metal strips by gluing, the sheet metal strips crumpling, i.e. H. are twisted so that the outer sheet metal strips come cyclically inwards and the inner ones outwards. A small current displacement is thus achieved.

8 shows a toroidal choke (1) with a plurality of winding segments or partial windings (22), each separated by insulating foils or insulating layers (23), which are arranged in a circle around the central recess (6) and whose geometry can be better seen in FIG. 10 are. The segment pitch angle is again designated with β. At the beginning and end of the overall winding composed of 360 ° / β ° partial windings, 2 separately designed power connection elements (30) and (31) are attached, which can be seen better in FIG. 9.

The hatched power connection element (31), which is led out upwards, forms a segment together with the power connection element (30), which is shown in dotted lines and is carried out horizontally, but which, unlike the other segments (22), does not Has outer web (40). Due to the interlacing of the segment (22), the two power connection elements (30, 31) are arranged one above the other and, like the other segments (22), are electrically insulated from one another by an insulating film (23) that can be seen better in FIG. 11. The insulating film (23) is slotted in the outer area as seen in the radial direction, so that there it has an upper and lower insulating film section (23a, 23b), which sections in FIG. 8 are only in the area of the power connection elements (30, 31 for reasons of clarity ) are shown in solid lines or dotted lines. The power connector (30) forms z. B. the beginning of the overall winding and the power connector (31), the z. B. could also be led out horizontally, the end.

FIG. 9 shows the toroidal choke (1) according to FIG. 8 in a vertical cross section through its center and additionally a central clamping bolt (28) in the recess (6), upper and lower insulating plates (25), an upper disk-shaped clamping plate (26) , a lower disc-shaped clamping plate (27) and an electrically insulated pressure bandage (29) around the middle part of the torus, d. H. around an outer edge (41) of the partial windings (22). The high-strength tensioning structure, made of steel or a glass fiber material, is designed in such a way that it can absorb the majority of the expansion forces of the winding that arise during a surge current load. (In the case of partial windings from a simple sheet metal cut, the insulating plates (25) would be provided with radial grooves.)

According to a preferred embodiment of the invention, the central clamping bolt (28) is connected to steel disc-shaped clamping plates (26, 27) by thread. The clamping bolt (28) has a central cavity or coolant channel (28a) in its interior. It is electrically insulated from the partial windings (22) by insulating rings (24).

For cooling by a coolant, preferably oil, a coolant inflow channel (34) and a coolant outflow channel (35) can be provided in a partial winding (2). The arrows show the direction of flow of the coolant. As an alternative, coolant can be drawn into the interior of the toroidal throttle (1) through slot-shaped openings or coolant inflow channels (32), and from there through coolant outflow channels (33) and the coolant channel (28a) inside the clamping bolt (28) get outside. It goes without saying that the current heat to be dissipated can alternatively or additionally also be dissipated to the surroundings by means of cooling fins (not shown). With (39) transition points to an adjacent, partial winding (22) lying behind are identified.

FIG. 10 shows a segment or a partial winding (22) of the toroidal choke (1) according to FIG. 8 from a solid winding in a perspective view in detail. The partial winding (22) has a 1st or initial connection piece (36) and a 2nd or end connection piece (37) with a lateral, vertical pressure contact surface (37 ') and a horizontal contact surface (37'') through a recess (38) are spaced apart. The upper insulating film section (23a) is pushed into this recess (38) during assembly of the toroidal choke (1). The remaining part of the insulating film (23) serves for the electrical insulation of a partial winding (22) from the neighboring one, cf. 8 and 11. When the toroidal choke (1) is assembled, the rear pressure contact surface of the initial connecting piece (36) of a partial winding (22), which cannot be seen in FIG. 8, comes to rest against the pressure contact surface (37 ') of the adjacent partial winding. An electrical connection is guaranteed by the contact pressure. Preferably, however, from the upper end face by a high-energy welding z. B. by means of an electron or laser beam, not shown Weld seam created, which ensures an even better electrical connection.

It is important that the start and end connecting pieces (36, 37) match one another or are designed to be complementary to one another, so that area contact is ensured when adjacent partial windings (22) are applied. Relatively thick partial windings (22) can be produced in the desired, spread shape by casting. Flat partial windings (22) can be made from an annular disk by cutting along a cutting line leading from the inside outwards, for. B. by means of a laser beam and subsequent bending or spreading. Adjacent partial windings (22) are then soldered or preferably welded along these cutting lines in order to obtain an overall winding.

Fig. 12 shows a section of a partial winding (39) with a flat design and enlarged outer surfaces to reduce high-frequency losses. An arrow (B) points in the direction of the connection point, not shown.

In sheet metal cuts, the connecting elements can be soft-soldered, hard-soldered or welded. Press and screw connections are suitable for solid partial windings. The partial windings (2) are inserted one after the other radially into a winding body, not shown, and the contact points z. B. fixed with screws.

(Only intended for the examination center; not part of the registration)

LIST OF DESIGNATIONS

1

Toroidal choke

2, 7-10, 13, 18, 22, 39

Partial windings, segments

2a

lower leg of 2

2 B

upper leg of 2

3rd

electrical connector

4th

Inner edge of 2

5

Outer edge of 2

6

Recess

11, 12

rectangular outer boundary, surfaces perpendicular to each other

13a, 13b

Fasteners from 13

14

Winding element

15

Isolation, insulating spacers

16

Connection area

17th

insulated connector end

18a

bevelled corners of 18

19th

Connection area

20th

Partial winding from stranded wire

21

Connection profile

23

Insulating layer, foil

23a

upper insulating film section

23b

lower insulating film section

24th

Insulating ring

25th

Insulating plate

26

upper clamping plate

27

lower clamping plate

28

Clamping bolt

28a

Cavity in 28, coolant channel

29

Pressure bandage

30, 31

Power connection elements

32, 34

Coolant inflow channels

33, 35

Coolant outflow channels

36

1. or initial connector

37

2. or end connector

37 '

Print area of 37

37 ''

Investment area of 37

38

Recess for 23

39

Transition point to the neighboring partial winding

40

Outside footbridge

41

Outside edge of 40 or 22

A-A

cut

a, b

Width of 2

B

arrow

c, d

Height of 2a

l

Length of 2

α

angle

β

Segmentation angle

Claims (10)

Toroidal choke (1) a) from a plurality of winding parts or partial windings (2, 7-10, 13, 18, 22, 39) arranged side by side to form a torus, b) wherein each partial winding has at least one turn and c) with at least one connecting element (3; 36, 37) for series and / or parallel connection of the partial windings in an electrically conductive connection, characterized, d) that the width (a) of legs (2a, 2b) of the partial windings (2) in a central, inner region (4) of the torus is smaller than the width (b) at the peripheral outer edge (5). Toroidal choke according to claim 1, characterized in a) that the height (c) of legs (2a, 2b) in the central, inner region (4) is greater than the height (d) at the peripheral outer edge (5) of the torus, such that a current cross-sectional area through each partial winding is no longer than 30%, b) in particular does not deviate by more than 10% from an average or nominal cross-sectional area (FIG. 1). Toroidal choke according to claim 1 or 2, characterized in that adjacent legs of partial windings (7-10) have different lengths, measured from the central, inner region (4) to the peripheral outer edge (5; 11, 12) of the torus (Fig. 2) . Toroidal choke according to one of claims 1 to 3, characterized in that a) that the peripheral torus is angular, b) in particular rectangular (11, 12) is limited (Fig. 3). Toroidal choke according to one of Claims 1 to 4, characterized in that a) that the partial winding (18) has a box profile with rounded or bevelled inner corners (18a), b) in particular that the outer surfaces of the partial windings (18) are enlarged relative to their inner surfaces (FIG. 6). Toroidal choke with the features a) to c) of claim 1, in particular according to one of claims 1 to 4, characterized in that a) that the partial windings (13) have 2 connecting elements (13a, 13b) which mutually have an inner angle (α) in the range from 90 ° to 150 °, b) Include in particular in the range of 100 ° - 130 ° (Fig. 4). Toroidal choke according to one of Claims 1 to 6, characterized in that a) that the partial windings (20) are formed from stranded wire, b) in particular that the partial windings are made from bolted or twisted sheet metal sections (FIG. 7). Toroidal choke according to one of claims 1 to 7, characterized in a) that the partial windings (22) have inner and / or outer cooling elements or cooling devices (32-35), b) in particular that a clamping bolt (28) with an inner coolant channel (28a) is provided in the center of the toroidal throttle (1) (FIG. 9). Toroidal choke according to one of Claims 1 to 8, characterized in that the partial windings (14) have a plurality of windings lying one above the other (Fig. 5). Toroidal choke according to one of claims 1 to 8, characterized in a) that at least one partial winding (22) is a winding part with one turn b) and has a first or initial connecting piece (36) with at least one first contact point and a spaced-apart second or end connecting piece (37) with at least one second contact point (37 ', 37''), c) which connecting pieces are mutually intertwined, d) in particular that the initial connection piece (36) has a fit in the form of a recess or a projection which is complementary to a fit (37 ') of the end connection piece (37), and e) that start and end connecting pieces (36, 37) of adjacent partial windings (22) are connected by means of a weld seam.

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