EP3501063B1 - Electrical contact arrangement and method for establishing electrical contact - Google Patents

Description

The invention relates to an electrical contact arrangement for high-voltage applications with a first and a second contact piece.

The two contact pieces are brought into connection with one another in a suitable manner in known contact arrangements for establishing electrical contact, so that an electrical current can flow through the contact pieces.

According to a known method for connecting the contact pieces, they are screwed together. In particular in high-voltage applications, such a screw connection must be made relatively massive, because high currents in the higher kA range can flow through the contact arrangement. Such a solidly designed contact arrangement is, however, associated with a great deal of effort in the production and separation of the electrical contact. Such a separation is necessary, for example, when servicing two components of a high-voltage system that are connected to one another via the two contact pieces. In particular, solving the massive screw connection is complex in this case. In addition, there is a need to securely stow loose fastening elements such as screws, nuts and washers, which further increases the effort.

US 2010/011571 discloses a contact arrangement for high voltage applications.

From the DE 10 2014 014 536 A1 an arrangement for establishing an electrical contact is known in which a clamping connection is established between elements to be contacted by rotating a partially eccentric control surface element.

Further arrangements of this type are also from the DE 28 27 241 A1 , of the U.S. 3,671,924 A as well as the U.S. 5,810,628 A known. The object of the invention is to propose a type-appropriate contact arrangement which is as reliable as possible in operation and which enables the electrical contact to be produced and separated as simply as possible.

The object is achieved in accordance with the invention with a type-appropriate contact arrangement in that, in order to produce an electrical contact, the second contact piece is rotated by means of a connected to the first contact piece and rotatably mounted, at least section-wide eccentric clamping rod between the first contact piece and the clamping rod can be clamped.

The term eccentric clamping rod is to be understood in connection with the invention such that the clamping rod has a cross section along its longitudinal direction at one or more points or sections or also along the entire length, such that a rotational movement of the clamping rod is converted into a translational movement in the manner of a Crankshaft can be converted.

In this sense, an eccentric clamping rod is, for example, a clamping rod with an elliptical cross-section, a single-edged or polygonal clamping rod, with a longitudinal edge of the clamping rod extending at least in sections along the longitudinal direction of the clamping rod, or a clamping rod with one or more eccentrics.

The contact arrangement according to the invention is thus designed in such a way that the two contact pieces can form a clamping connection with one another to produce the electrical contact. The clamping connection is achieved by rotating the clamping rod and can thus be released. The jamming of the contact pieces can be reversed by turning the clamping rod in the opposite direction.

A significant advantage of the contact arrangement according to the invention is the reduced effort involved in separating the electrical contact. There is no need to solve massive screw connections, which reduces the time required. No loose fasteners are used. The contact pieces are clamped by simply and quickly rotating the clamping rod. In this way, the time required for making and separating the electrical contact can be reduced. At the same time, the clamp connection is the Contact pieces ensure reliable electrical contact even with high currents through the contact arrangement.

A clamping force achieved when the contact pieces are jammed is expediently selected in such a way that it corresponds, for example, to the force of a corresponding screw connection. This results in a functional dependence on the area, since a clamp connection normally has larger effective areas than a comparable screw connection.

According to one embodiment of the invention, the contact pieces are at least partially flat and, in a jammed state of the contact arrangement, bear against one another at least in sections, the clamping rod being arranged in such a way that a longitudinal edge of the clamping rod exerts a pressing force on the contact pieces that are in contact with one another at least in sections, so that the second contact piece is releasably clamped between the first contact piece and the clamping rod. Accordingly, the clamping rod is an angular clamping rod with a longitudinal edge along the longitudinal direction of the clamping rod. The second contact piece can accordingly be inserted between the first contact piece and the clamping rod in order to establish the electrical contact, so that the two contact pieces are at least partially one above the other and lie flat against one another. The clamp rod can then be rotated through a predetermined angle. After the rotation, the longitudinal edge of the clamping rod suitably points in the direction of the contact pieces and exerts the pressing force on them. The clamping rod can be connected to the first contact piece, for example by means of suitable screw elements. The contact pieces can be separated in a simple manner by turning the clamping rod in the opposite direction and pushing out the second contact piece.

The contact pressure can preferably be transmitted to the contact pieces via a spring element. Accordingly, at least one spring element is provided, which is arranged such that the Contact pressure in the clamped state from the clamping rod via which at least one spring element is transmitted to the contact pieces. The use of the spring element means that the contact pressure is transmitted particularly homogeneously. Our own studies have shown that the electrical contact is particularly reliable in this way. Even with very high currents through the contact arrangement, there are essentially no prominent current marks or weak points on the contact pieces.

It is considered to be particularly advantageous if the spring element comprises at least one disc spring. The at least one plate spring can be arranged on a side of the clamping rod facing the first contact piece. In the jammed state, the longitudinal edge of the clamping rod presses on the plate spring, which transfers the contact pressure to the contact pieces. According to a variant, several disc springs are provided, which are arranged along the clamping rod. Disc springs have the advantage of a particularly homogeneous power transmission.

According to one embodiment of the invention, a return spring is provided, which is arranged such that a spring force of the return spring acts against the contact pressure. The return spring can be arranged, for example, in an interior of the plate spring. The function of the return spring is to create a distance between the clamping rod or the plate spring and the first contact piece when the contact arrangement is not in the clamped state. The distance between the clamping rod or plate spring and the first contact piece is expediently dimensioned such that the second contact piece can be pushed in between the first contact piece and the clamping rod or plate spring without any problems. In this way, a further simplification of the production and separation of the electrical contact is achieved. The return spring can for example be a spiral spring.

In high-voltage applications with nominal voltages of several kV, high nominal currents of several hundred kA can occur. In addition, peak currents of over 1 MA can occur. The contact arrangement is therefore to be designed for at least briefly conducting currents above 1 MA, particularly preferably above 1.5 MA.

The longitudinal edge of the clamping rod preferably has a bevel. In other words, the longitudinal edge is flattened. In particular, this prevents the clamping rod from slipping laterally or twisting when the contact arrangement is jammed, so that the clamping rod can no longer exert sufficient contact pressure.

According to one embodiment of the invention, the clamping rod has a polygonal cross section. For example, the clamping rod can be a square. A polygonal design of the clamping rod has the advantageous effect that the reliable rotation of the clamping rod is facilitated. The clamping rod can be rotated, for example, by means of a suitable tool which has a recess corresponding to the cross section of the clamping rod.

The invention further relates to an electrical device with a switching module which comprises at least one power semiconductor switch, and with a memory module.

Such an electrical device is used, for example, in systems for high-voltage direct current transmission (HVDC). So-called power modules are used there, which are connected to one another in a series connection, for example. Each power module is also connected to an energy store, suitably a capacitor. In the event of a power module failure and maintenance work on the power modules, the connection between the power module and the capacitor must be disconnected.

The object of the invention is to provide a type of electrical device that is as reliable and easy to maintain as possible.

The object is achieved in the case of an electrical device of this type in that an electrical contact can be established between the switching module and the storage module by means of a contact arrangement according to the invention.

The advantages of the electrical device according to the invention result in particular from the advantages of the contact arrangement according to the invention described above. Due to the simple production and separation of the contact, the maintenance time can in particular also be shortened.

All of the exemplary embodiments and variants of the contact arrangement according to the invention described above can also be implemented in connection with the device according to the invention.

If the switching module and the storage module are to be connected to one another via more than one electrical contact, it is of course possible to produce one or more of the contacts by means of the contact arrangement according to the invention.

The switching module can comprise a plurality of power semiconductor switches which are connected to one another in a half-bridge circuit. According to other variants, the switching module is implemented as a full bridge circuit, double-clamp circuit or other suitable circuit known to those skilled in the art. A series connection of the switching modules can form a phase branch of a modular multistage converter known to the person skilled in the art, the phase branch extending between a DC voltage pole and an AC voltage connection of the multistage converter.

The invention also relates to a method for producing an electrical contact between two at least partially flat contact pieces.

The invention is based on the object of specifying such a method that enables an electrical connection of the contact pieces that is as reliable as possible and at the same time simple to produce and disconnect.

The object is achieved with such a method according to the invention in that the contact pieces are placed against one another at least in sections and an angular clamping rod connected to the first contact piece and rotatably mounted along a longitudinal axis is rotated by a predetermined angle of rotation so that a longitudinal edge of the clamping rod exerts a pressing force exerts on the at least partially abutting contact pieces, wherein the second contact piece is clamped between the first contact piece and the clamping rod.

The advantages of the method according to the invention result in particular from the use of the contact arrangement according to the invention. In particular, when servicing the components that are electrically contacted by means of the method according to the invention, the advantages already described with regard to reduced servicing time and expenditure arise.

The method according to the invention is suitable for use with all of the previously described embodiments and variants of the contact arrangement according to the invention.

• Figur 1 zeigt ein Ausführungsbeispiel einer erfindungsgemäßen Kontaktanordnung in einer schematischen Darstellung;
• Figur 2 zeigt das Ausführungsbeispiel der Figur 1 in einer schematischen Seitendarstellung;
• Figur 3 zeigt einen Ausschnitt eines weiteren Ausführungsbeispiels der Kontaktanordnung in einer schematischen Darstellung;
• Figur 4 den Ausschnitt der Figur 3 in einem verklemmten Zustand der Kontaktanordnung;
• Figur 5 zeigt ein Ausführungsbeispiel einer erfindungsgemäßen elektrischen Einrichtung in einer schematischen Darstellung.

The invention is intended in the following with reference to Figures 1 to 5 further explained.

• Figure 1 shows an embodiment of a contact arrangement according to the invention in a schematic representation;
• Figure 2 shows the embodiment of Figure 1 in a schematic side view;
• Figure 3 shows a section of a further embodiment of the contact arrangement in a schematic representation;
• Figure 4 the section of the Figure 3 in a jammed state of the contact arrangement;
• Figure 5 shows an embodiment of an electrical device according to the invention in a schematic representation.

In particular, in Figure 1 an embodiment of a contact arrangement 1 according to the invention is shown. The contact arrangement 1 comprises a first contact piece 2 and a second contact piece 3. In the present exemplary embodiment, the first contact piece 2 forms a pole of an in Figure 1 memory module not shown figuratively. The second contact piece 3 forms a busbar for connection to a switching module, also not shown in the figures. Both contact pieces 2, 3 are at least partially flat and in the illustration of Figure 1 lying on top of each other in sections.

A square clamping rod 4 is connected to the first contact piece 2 via connecting means 51, 52. Two disc springs 61 and 62 are arranged between the clamping rod 4 and the first contact piece 2.

The second contact piece 3 has two recesses 71 and 72. An opening width of the recesses 71, 72 is each slightly larger than a diameter of the cylindrical connecting means 51 and 52, but smaller than a diameter of the disc springs 61 and 62. In this way, the second contact piece 3 between the disc springs 61, 62 and the first contact piece 2 are pushed so that the two contact pieces abut one another in sections.

In Figure 2 Figure 3 is a side view of the assembly of Figure 1 Figure 1 shown. For the sake of clarity, the Figures 1 and 2 Identical parts are provided with the same reference numerals.

It can be seen that the connecting means 51 have a fastening foot 8 which ensures a firm lock with the first contact piece 2 (for example by screwing).

In the representation of the Figures 1 and 2 the contact arrangement 1 is in a jammed state. The two contact pieces 2 and 3 are clamped to one another, so that a reliable electrical contact is established between the contact pieces 2, 3 for conducting high currents of several kA. For this purpose, the clamping rod 4 is in a position in which a longitudinal edge 9 of the clamping rod 4 (in the present example one of four longitudinal edges) points in the direction of the second contact piece 3. In this position, the clamping rod 4 exerts a pressing force on the plate spring 61. The plate spring 61 transmits this pressing force to the two contact pieces 2 and 3 and ensures that they are jammed. The plate spring 61 also enables a homogeneous force distribution over the area to the contact pieces 2, 3.

The basic functional principle of making electrical contact is in the Figures 3 and 4 shown in more detail using the example of a contact arrangement 10 according to the invention. For the sake of clarity, the Figures 3 and 4 only a square clamping rod 11 and a plate spring 12 are shown. The rest of the design of the contact arrangement 10 corresponds to that according to the exemplary embodiment of FIG Figures 1 and 2 .

In the representation of the Figure 3 the clamping rod 11 is in a position in which the plate spring 12 is relaxed. A side length L of the clamping rod is indicated by a double arrow. The clamp rod 11 is with respect to a Rotatable longitudinal axis. The longitudinal axis runs perpendicular to the plane of the drawing.

To produce an electrical contact between the contact pieces, the clamping rod 11 is rotated through a predetermined angle. Specifically, the clamping rod 11 is rotated until a longitudinal edge 13 points in the direction of the contact pieces or the plate spring 12. The rotation of the clamp rod 11 is in Figure 4 indicated by an arrow W and takes place in the example shown at an angle of 45 °. A diagonal diameter of the clamping rod 11 is marked with a double arrow D.

The distance between a center point of the clamping rod 11 and the first contact piece is constant, so that the clamping rod 11 in the in Figure 4 position shown exerts a pressing force on the plate spring 12. The plate spring 12 deforms due to the contact pressure and transfers this over a large area to the contact pieces, so that the second contact piece is clamped between the clamping rod 11 and the first contact piece. A return spring 14 is arranged in an interior space of the plate spring 12. The return spring 14 is a coil spring. If the contact arrangement 10 is not in the jammed state, the return spring 14 is relaxed. It ensures a distance between the first contact piece and the clamping rod 11 and thus facilitates the insertion of the second contact piece between them. In the jammed state of the contact arrangement 10, which is shown in FIG Figure 4 is shown, the return spring is compressed. Here, the spring force of the return spring acts against the contact pressure.

The longitudinal edge 13 of the clamping rod 11 has a bevel 131. The longitudinal edge 13 is therefore not pointed, but has a flattening. In the jammed state of the clamping arrangement 10, the bevel 131 ensures that the clamping rod 11 is out of its position (as in FIG Figure 4 ) does not slip out and thus increases the reliability of the electrical contact between the contact pieces.

In the Figure 5 an embodiment of an electrical device 15 according to the invention is shown. The electrical device 15 comprises a switching module 16 which has two external connections 17 and 18. The switching module 16 can be connected by means of the connections 17 and 18 to other structurally identical switching modules, for example forming a series circuit. The switching module 16 comprises two power semiconductor switching units 19, 20, each of which comprises an IGBT switch (191, 192) and an anti-parallel diode. The power semiconductor switching units 19, 20 are connected to one another in a manner known to those skilled in the art as a half-bridge circuit. The switching module 16 also includes two terminals 21 and 22 for connection to a memory module 23.

The storage module 23 comprises a capacitor. The memory module 23 further comprises two terminals 24 and 25 for connection to the switching module 16.

The connection of the terminal 21 of the switching module 16 to the terminal 24 of the memory module 23 takes place by means of the contact arrangement 1, which has the structure according to the embodiment of Figures 1 and 2 having. Correspondingly, the connection of the terminal 22 of the switching module 16 to the terminal 25 of the memory module 23 takes place by means of a further, structurally identical contact arrangement 1.

Claims (8)

1. Electrical contact arrangement (1) for high-voltage applications, having a first contact piece (2) and a second contact piece (3), characterized in that, in order to establish electrical contact, the second contact piece (3) can be clamped, by rotating a clamping rod (4) which is connected to the first contact piece (2), is rotatably mounted and is eccentric at least in sections, between the first contact piece (2) and the clamping rod (4), wherein the contact arrangement (1, 10) is designed to conduct currents above 1 MA.
2. Contact arrangement (1) according to Claim 1, wherein the contact pieces (2, 3) are at least partially flat and rest against one another at least in sections in a clamped state of the contact arrangement (1), wherein the clamping rod (4) is arranged in such a manner that a longitudinal edge (9) of the clamping rod (4) exerts a pressing force on the contact pieces (2, 3) which rest against one another at least in sections, with the result that the second contact piece (3) is releasably clamped between the first contact piece (2) and the clamping rod (4).
3. Contact arrangement (1) according to Claim 2, wherein the pressing force can be transferred to the contact pieces via a spring element (61, 62).
4. Contact arrangement (1) according to Claim 3, wherein the spring element (61, 62) comprises at least one plate spring.
5. Contact arrangement (10) according to Claim 4, wherein a restoring spring (14) is provided and is arranged in such a manner that a spring force of the restoring spring (14) acts counter to the pressing force.
6. Contact arrangement (10) according to one of the preceding claims, wherein the clamping rod (11) has a polygonal cross section.
7. Contact arrangement (10) according to Claim 6, wherein the longitudinal edge (13) of the clamping rod (11) has a bevel (131).
8. Electrical device (15) having a switching module (16), which comprises at least one power semiconductor switch (191, 192), and having a storage module (23), wherein electrical contact can be established between the switching module (16) and the storage module (23) by means of a contact arrangement (1) according to one of Claims 1 to 7.

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