CH679532A5 - - Google Patents

Description

1

CH 679 532 A5

2nd

description

Technical field

The invention is based on a capacitor parallel circuit according to the preamble of claim 1. The invention also relates to the use of the capacitor parallel circuit.

State of the art

With the preamble, the invention relates to a prior art as known from EP-A1 0 185 181. In the case of the low-inductance anode-cathode circuitry of a tablet-shaped, switchable GTO power thyristor specified there, by avoiding the leakage inductances of circuit diodes, capacitors and line connections of the switch-off relief circuit, its switch-off current can be increased and the pulse wave voltage at the power thyristor can be reduced when it is switched off. Diodes, capacitors and thyristors have the same component axis direction; they are connected by means of essentially parallel, electrically conductive plates and symmetrical, bell-shaped caps or wire connections between the plates and the connection terminals of the components. Diodes and capacitors connected directly in series can be connected to the power thyristor via a coaxial cable. In this version, it is not possible to connect capacitors in parallel.

For large outputs, such as those required in traction, parallel connections of e.g. 24 capacitors, especially in the intermediate circuit of the converter, are required. If all capacitors are arranged in parallel next to each other, a lot of space is needed in width, which is scarce in vehicles.

Presentation of the invention

The invention, as defined in claim 1, solves the problem of further developing a capacitor parallel connection of the type mentioned at the outset in such a way that a plurality of capacitors connected in parallel can be accommodated in a width-saving manner with less space requirement.

An advantage of the invention lies in the fact that several capacitors can be better accommodated in a confined space, it being possible to use a space which is available in height for accommodating the capacitors. The arrangement according to the invention is particularly suitable for electric vehicle drives with a small space for accommodating drive components.

Brief description of the drawings

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

1 shows a typical application example for a parallel capacitor connection in the DC link of a converter for a vehicle drive,

FIG. 2 shows an arrangement of two parallel-connected capacitors in the DC intermediate circuit according to FIGS. 1 and

Fig. 3 shows a capacitor parallel connection of 8 capacitors. v,

Ways of Carrying Out the Invention

In Fig. 1, (1) denotes an AC power line of a rail network with an AC voltage of 15 kV and a network frequency of 16 2/3 Hz.

A converter transformer (2) grounded via wheels of a traction vehicle is connected on the primary side via a switch to a surge arrester, an earthing switch and the AC line (1) and on the secondary side, starting from 2 secondary windings, via a resistor and 3 switches with 4 rectifiers (3 ) of an inverter (3-7). The converter, which consists of 4 rectifiers (3), a DC link (4) and 3 inverters (7), is connected on the output side to 4 three-phase machines (8) connected in parallel to drive the locomotive.

The DC voltage intermediate circuit (4) has earthing switches connected in series for a positive (+) and negative (-) voltage rail, an harmonic suction circuit, consisting of a suction circuit choke (5) in series with a suction circuit capacitor (6), 2 parallel intermediate circuit capacitors ( C1, C2) and an overvoltage protection circuit, consisting of a GTO thyristor in series with a resistor, between the positive and negative voltage rails. The DC link voltage is 3 kV.

FIG. 2 shows the arrangement of the DC link capacitors (C1, C2) of FIG.

1, which are metal-paper capacitors with capacitance in the range of 1mF-25mF each. Each of the DC link capacitors (C1, C2) has 2 power connections or capacitor connection elements (9) and (10) of approx. 10 cm in length / which protrude vertically from an end cover (12) of the DC link capacitors (C1, C2) and the screw connections for connecting plates (13, 14).

The two intermediate circuit capacitors (C1, C2)

face each other with their capacitor connection elements (9, 10). The two capacitor connection elements (9) are electrically connected via the connecting plate (13) screwed to them with an inner conductor (16) with a 14 mm diameter of a coaxial cable (16-18) or connected to it by means of a

ner screw nut (15) attached. The two capacitor connection elements (10) are electrically connected to a v * outer conductor (18) of the coaxial cable (16-18) via the connecting plate (14) screwed to them, which between the inner and outer conductors (16, 18) has a cable insulation (17) having.

The connecting plates (13, 14) have a thickness of 1.5 mm; they are made of copper or preferred5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

2nd

3rd

CH 679 532 A5

4th

made of stainless steel, especially chrome steel. In the area between the capacitor connection elements (9, 10) they are bent in a U-shape and in the middle they are sandwiched or layered to the coaxial cable (16-18), spaced apart by a T-shaped insulator (11) made of a thermosetting plastic. In the U-shaped area, the connecting plates (13, 14) have a minimum distance (d) of 5 mm from the adjacent capacitor connection elements (9, 10). There is a distance (A) of 20 cm between the ends of the U-shaped sections of a connecting plate (13, 14). These ends are electrically insulated from the T-shaped insulator (11a) of the T-shaped insulator (11), which extends parallel to the end cover (12). In the area of the connection to the coaxial cable (16-18), the insulator (11) has an insulating pipe socket (11b), which separates the inner conductor (16) of the coaxial cable from a pipe socket (14b) of the connecting plate (14), which holds the inner conductor in Surrounds the connection area, electrically isolated at a distance.

FIG. 3 shows 8 DC link capacitors (C11-C14, C21-C24) connected in parallel, of which 2 each face each other with their capacitor connection elements (9), in a view perpendicular to FIG. looking from the left. Here you can see in the connection area of the capacitor connection elements (9) the connecting plate (13) and the T-shaped insulator (11) projecting above it, both of which extend over the entire length of the 4 intermediate circuit capacitors (C11-C14, C21-C24) arranged next to each other . With (19) holes for the connection of two coaxial cables are designated.

It goes without saying that instead of 2 or 8 intermediate circuit capacitors (C1, C2; C11-C14, C21-C24), other multiples of 2 can also be connected in the same way. The intermediate circuit capacitors can also be star-shaped (not shown) around a central axis, e.g. the connection point of the coaxial cable can be arranged, with 2 each with their capacitor connection elements lying opposite one another.

Instead of the T-shaped thermoset insulator (11), an insulating film can also be used. The connecting plates (13, 14) could also be covered with an insulating layer.

Instead of being U-shaped between the capacitor connection elements (9, 10), the connecting plates (13, 14) could also, as indicated by dashed lines with (13a) or (14a), run directly from these capacitor connection elements to the center between them or directly bent to the coaxial cable (16-18).

Furthermore, it goes without saying that the coaxial cables (16-18) can also be coated on the outside with an insulating sleeve or layer. It is important that the connection from the DC link capacitors to the coaxial cable or to the coaxial cables is low-induction in order to ensure that GTO thyristors in the rectifiers (3) and / or inverters (7) are safely switched off. These GTO thyristors (not shown) are connected to the intermediate circuit capacitors (C1, C2; CUCI 4, C21-24) via the coaxial cable (16-18).

Claims (8)

Claims 1. capacitor parallel connection a) with at least 2 capacitors (C1, C2; C11-C14, C21-24), each having at least 2 electrical capacitor connection elements (9, 10), via which the capacitors are electrically connected in parallel, b) wherein the capacitor connection elements of 2 capacitors are arranged opposite one another, characterized in that c) that the capacitor connecting elements (9, 10) are electrically connected to at least one coaxial cable (16-18) via connecting plates (13, 14) and c) that the connecting plates run parallel to one another in sections. 2. parallel capacitor circuit according to claim 1, characterized in that the connecting plates (13, 14) between the capacitor connection elements (9, 10) of a capacitor (C1, C2) are U-shaped. 3. capacitor parallel circuit according to claim 1 or 2, characterized in that n ■ 2 capacitors are arranged in a star shape to each other, n> 2. 4. capacitor parallel circuit according to one of claims 1 to 3, characterized in that the connecting plates (13, 14) have stainless steel. 5. parallel capacitor connection according to one of claims 1 to 4, characterized in that the connecting plates (13, 14) are formed in sections in layers with an intermediate insulator (11). 6. capacitor parallel circuit according to claim 5, characterized in that the insulator (11,11a) between the capacitor connection elements (9,10) of a capacitor (C1, C2) is T-shaped for insulation of the connecting plates (13,14) from each other and against earth potential. 7. capacitor parallel circuit according to one of claims 1 to 6, characterized in that the coaxial cable (16-18) at least in the region of its connection to the connecting plates (13, 14) perpendicular to the arrangement of the opposing capacitors (C1, C2; C11 -C14, C21-C24). 8. Use of the capacitor parallel circuit according to one of claims 1 to 7 for intermediate circuit capacitors of a direct voltage intermediate circuit (4) of a converter (3-9). 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65