Current lead and current transformer arrangement with such current lead

Abstract

The invention relates to a current lead (11) having at least one pipe section (12) embodied as a pipe, which pipe (12) is used here for conducting coolant and is composed here of a material having an electrical resistance of at least 0.075 μΩm. At least two coolant ports (15, 17, 18) and at least two current terminals (04, 16) spaced apart from one another are required, which current terminals (04, 16) are arranged adjacent to the coolant ports (15, 18), respectively.

Description

TECHNICAL FIELD

[0001] The invention relates to a current conduit for use in a converter arrangement, wherein the current conduit is provided for electrical connection between a DC voltage network and a plurality of converters. BACKGROUND

[0002] Generally used converter arrangements generally comprise a plurality of converters which are jointly connected to a DC voltage network on the DC voltage side. Here, the converters are arranged side by side, so that they can all be connected to one another via short conduit sections. Here, a main busbar consisting of a very good electrically conductive material, i.e. copper, is used in principle, which is guided along the converters on one side. From the main busbar, short connection tracks are then connected to the converters.

[0003] The apparent advantages of the arrangement are simple construction, low resistance and thus small losses through the connection arrangement.

[0004] However, in the current converters, problems in this parallel arrangement sometimes manifest themselves as a disadvantage, i.e. excitation can occur in the connection arrangement by the converters due to system-generated pulses. This in turn loads the entire converter arrangement in an undesirable manner.

[0005] In order to avoid harmful pulses, intermediate circuit capacitors are generally used for damping or decoupling chokes are used for filtering out undesirable frequencies.

[0006] However, this solution in turn leads to undesirable power losses in the converter arrangement. SUMMARY

[0007] It is therefore the object of the invention to provide an alternative to the usual measures for reducing pulses, which has smaller power losses.

[0008] The proposed object is achieved by an embodiment of the current conduit according to the teaching of claim 1 according to the invention. A converter arrangement according to the invention is specified in claim 7. Advantageous embodiments are the subject of the dependent claims.

[0009] Unlike this form with a main busbar consisting of a very good electrically conductive material, a current conduit consisting of a material with higher electrical resistance is used according to the invention. Here, the current conduit comprises a pipe section, at least two coolant ports and at least two current terminals.

[0010] The current terminals are conductively connected to the line section and are arranged spaced apart from one another such that a current loop via the line section can be established via the current terminals. The current terminals can here be not only mounted at the line section but also fixedly connected to the line section, for example via a solder connection. Here, the current terminals can be arranged not only at one end or both ends of the line section but also in the extension of the line section.

[0011] The line section here is constituted in the form of a tube, it being unimportant whether the tube has a circular or angular or other cross section, and serves for the guidance of a coolant. It is unimportant here at first which type of coolant it is and in this respect can be not only a liquid but also a gas. For this purpose, coolant ports are arranged spaced apart from one another, wherein the coolant ports can be arranged not only at the ends of the line section but also in the extension of the line section. The coolant ports serve at least for the input or output of a cooling medium into or from the line section.

[0012] By guiding the coolant via the line section which simultaneously serves as a current conductor, on the one hand, the delivery of the coolant to another location is achieved and, in particular, the cooling of the line section itself is carried out at the same time. For this purpose, it is also proposed that one coolant port is arranged adjacent to each of the at least two current terminals. It is unimportant here that the current terminals are arranged directly side by side at the line section. Rather, it should be achieved that the input or output of the coolant is effected spatially close to the connection of the current terminals.

[0013] Here, the main feature of the invention is that the material constituting the line section has an electrical resistance of at least 0.075 μΩm.

[0014] It has proved to be advantageous that the material used for the manufacture of the line section has a specific resistance of at least 0.25 μΩm. Here, it is particularly advantageous that the specific resistance is at least 0.5 μΩm.

[0015] It is apparent that the line losses increase with the specific resistance of the material used (under the assumption that the cross section remains constant). Correspondingly, the electrical resistance should be not larger than 2 μΩm, particularly advantageously not larger than 1 μΩm.

[0016] Since the current to be transmitted has to be guided via the current terminals and the current terminals can be cooled worse by the coolant flowing through the line section, it is advantageous in contrast thereto that the current terminals are manufactured from a different material and that the material has a specific resistance of at most 0.05 Ωμm. It is particularly advantageous to use a material having an electrical resistance of at most 0.025 μΩm. Thus, an excessive heat generation in the current terminals can be avoided.

[0017] In the presence of a main terminal, in particular for the connection to the power grid, and at least two or more branch lines, for example in the case of a connection to a converter each, the main terminal is clearly subjected to a stronger electrical load. In this regard, it is particularly advantageous if at least the main terminal is made of a material having a particularly small electrical resistance, for example copper.

[0018] It is particularly advantageous to use the current conduit when the current conduit is used for conducting a direct voltage.

[0019] The embodiment and arrangement of the current terminals spaced apart from one another is initially unimportant. It is, however, particularly advantageous if a main terminal is provided as a current terminal at the end of the line section. This not only enables advantageous use of the length of the line section but also enables a simpler implementation of the main terminal.

[0020] Since the line section is provided by specification for conducting a coolant, it is furthermore advantageous if a supply port is present as a coolant port at at least one end of the line section. This enables cooling of the line section up to the end on the one hand and likewise simple arrangement of the supply port at the closure element.

[0021] It can be proposed here that an advantageous main terminal is provided at the opposite end of an advantageous supply port. Conversely, it can also be proposed that the main terminal and the supply port are provided at the same end. In order to optimally flush the line section, it is particularly advantageous if a supply port is provided at both ends.

[0022] It is furthermore particularly advantageous if the current conduit is connected to a converter. It can be proposed here that the connection takes place via a main terminal provided at the end. However, it is advantageous if the connection of the converter can take place at a current terminal provided spaced apart from the end.

[0023] The use of the current conduit is particularly advantageously designed when two converters can be connected at the same time. To this end, it is preferred if two current terminals are provided spaced apart from the ends at the line section.

[0024] It is furthermore advantageous if, for example, a converter can be supplied with cooling liquid via the current conduit. To this end, it is advantageous if a coolant port is provided adjacent to a current terminal. By providing one current terminal, particularly advantageously two current terminals, in the extension of the line section, it is correspondingly advantageous if at least one coolant port, particularly advantageously two coolant ports, is provided at the line section spaced apart from the ends of the line section.

[0025] Depending on the length of the current conduit, its fastening and the installation of the coolant line and / or the current line, it can be advantageous to implement an expansion compensation mechanism. To this end, the current conduit comprises a first line section and at least one second line section, wherein the line sections are connected to one another via an expansion compensation mechanism.

[0026] In this, in the first embodiment it can be proposed that the expansion compensation mechanism at the same time with the component implements the guiding of the coolant from one line section into the other and implements the current guidance to some extent. For this, the expansion compensation mechanism can be implemented for example in the form of an electrically conductive and coolant-guiding bellows. Alternatively, it is possible to propose a tube stretch which connects the two ends of the line section to each other in a U-shaped or meandering manner.

[0027] In the particularly advantageous second embodiment, the expansion compensation mechanism between the two opposite ends of the line section comprises a coolant-guiding bellows or compensator. Here, an electrical conductivity of the bellows or compensator is not required. For this, it is proposed that the two ends of the line section are connected to each other via an electrically conductive bridge which surrounds the bellows or compensator. Thus, the bellows or compensator can for example comprise a plastic material or a rubber-like material, whereas the bridge, in contrast, is made of a material which is preferably very well electrically conductive.

[0028] It is proposed according to a provision that the coolant guidance takes place via coolant ports, whereas the current guidance takes place via current terminals. In order to prevent a current guidance via the coolant ports, it can be proposed that the coolant ports are at least partially, in particular in the contact face, composed of an electrically non-conductive material.

[0029] If no supply port is provided at one end of the line section on the end side, the current conduit advantageously has at said end one closing element for closing the line section. In particular when the main terminal is provided at said end, it is furthermore advantageous if the closing element simultaneously forms the main terminal.

[0030] As described above, the current conduit according to the application implements an implementation variant of a converter device according to the application. Here, the converter device comprises a first current conduit and a second current conduit which is separate from the first current conduit and which is implemented in correspondence with the preceding description. Furthermore, the converter device comprises at least one converter. It is proposed here that the converters are each connected via at least one electrically conductive busbar to the respective current terminal of the first current conduit or of the second current conduit. It is furthermore proposed that the converters are each connected at the same time via an electrically non-conductive coolant tube to the respective coolant port of the first current conduit or of the second current conduit. Thus, the converters can be combined into the electrical network via the current conduit and at the same time be supplied with coolant.

[0031] The use of a current conduit according to the application is advantageous if the converter device has at least two converters, particularly advantageously at least three converters, which are connected jointly on both current conduits. It is apparent that, therefore, a corresponding number of current terminals and coolant ports at the respective current conduit is required.

[0032] Here, the connection of the converter is carried out in a preferred manner, such that the converter is connected with the current ducts with the direct voltage side and, in this regard, uses the current ducts for guiding the direct voltage.

[0033] In a further advantageous embodiment, a coolant supply device is provided for forming the converter device, which is connected via an electrically non-conducting first port tube to a first supply port of the first current duct and via an electrically non-conducting second port tube to a second supply port of the second current duct. Thereby, the supply of coolant as well as the circulation of coolant is achieved.

[0034] For this purpose, the coolant supply device has in an advantageous manner at least one coolant pump as well as at least one cooling device. Thereby, the circulation of coolant is supported as well as a corresponding desired low temperature of the coolant is provided.

[0035] In order to avoid dead volumes in the current ducts, as soon as the current ducts are not directly connected at their end opposite to the port to the coolant supply device, for example, on the converter, it is advantageous that the current ducts have at their end opposite to the port to the coolant supply device a supply port each, which are connected to each other via electrically non-conducting, for example, with small cross section, connection tubes in order to achieve a cooling circulation loop through the connection tubes.

[0036] Furthermore, it can be proposed that, in order to improve the damping or suppression of vibrations, a capacitor can be connected via a further current terminal on both current ducts. However, here no adjacent coolant ports are required.

[0037] A particularly advantageous converter device is obtained when the converter device is connected to a direct voltage network. For this purpose, the respective main terminals of the two current ducts are connected with the direct voltage network. It is proposed here that a consumer (arbitrary type of consumer, for example, a motor, a battery, etc.) is connected on the direct voltage network. BRIEF DESCRIPTION OF DRAWINGS

[0038] In the following figures, a converter device according to the application with current ducts according to the application is depicted. The figures show:

[0039] Figure 1 An embodiment of an exemplary converter device with three converters is shown;

[0040] Figure 2 An exemplary current duct with respect to Figure 1 is shown;

[0041] Figure 3 A pipe section used in the current duct in Figure 2 is shown;

[0042] Figure 4 A current duct inFigure 2 bends used in the current conduit in

[0043] Figure 5 bridges used in the current conduit in Figure 2 DETAILED DESCRIPTION

[0044] An exemplary embodiment of a current transformer device 01 according to the application is schematically depicted in Figure 1 The current transformer device comprises as basic elements two current conduits 11 (+), 11 (-). Three current transformers 02 are connected on the current conduits 11 (+), 11 (-). Here, the current conduits 11 (+), 11 (-) have two functions.

[0045] The main purpose lies in the current conduction, here from / to the main terminals 04 (+), 04 (-) via the line sections 12 to the respective current terminals 16, which are arranged at the respective end of the current conduit 11. The current transformers 02 are connected with the current terminals 16 via the busbars 06 (+), 06 (-).

[0046] At the same time, the respective current conduit 11 fulfils the function of conducting coolant. For this purpose, the current conduit 11 is implemented hollow. Here, the current conduit 11 has at one end (here opposite the main terminal) a supply port 17 (+), 17 (-), which is connected via the electrically non-conductive port tube 07 (+), 07 (-) with the coolant supply device 03. Coolant ports 15 are arranged in the stretch of the line section 12. Thus, a coolant flow from / to the coolant supply device 03 to / from the coolant ports 15 is achieved. Here, the coolant supply device 03 has a coolant pump for conveying the coolant and a cooling device for cooling the coolant.

[0047] It is important that the following possibility is available, that the current transformers 02 can be connected on two current conduits 11, more precisely to one current terminal and at the same time to one coolant port.

[0048] In order to avoid dead volumes in the current conduit 11, it is furthermore proposed that, opposite the supply port 17 connected with the coolant supply device 03, a further supply port 18 (+), 18 (-) is present. Here, the two further supply ports 18 are connected with one another via the electrically non-conductive connection tube 08. Since coolant is required, inter alia, for cooling the current transformers 02, a comparatively small cross section for the connection tube can be chosen.

[0049] An exemplary embodiment of a current conduit 11 is depicted in Figure 2 Figure 1 ​​as in the double use of the electrically conductive body arrangement 01. In the embodiment described, the current duct 11 comprises three sections, which each have a line section 12, which is embodied in the type of a tube.

[0050] At each of the three line sections 12, which are again depicted in Figure 3 , a coolant port 15 is arranged and adjacent thereto a current terminal 16.

[0051] The connection of the two line sections 12 takes place via an expansion compensation mechanism, via which it must be ensured not only the current conduction but also the coolant guidance. For this purpose, the expansion compensation mechanism has the function of realizing small length changes, which are caused for example by the thermal expansion of the line sections 12.

[0052] In the embodiment described, the expansion compensation mechanism comprises a bellows 13 - see Figure 4 , which realizes the guidance of the coolant from one line section 12 into the adjacent line section 12.

[0053] Since the bellows 13 is not required to be electrically conductive here, the two opposite ends of the line section 12 are connected to one another via a bridge 14 - see Figure 5 . The bridge 14 serves here for the current guidance and should have here a particularly small electrical resistance. The bridge 14 has here a U-shape and thus also a certain elasticity.

Claims

1. A current lead (11) having at least one tube section (12) which is configured as a tube for conducting coolant and which is composed of a material having a specific resistance of at least 0.075 μΩm, not more than 2 μΩm, and at least two coolant ports (15, 17, 18) to which coolant tubes (05, 07, 08) can be connected respectively, and at least two current terminals (16) which are spaced apart from one another, are electrically conductively connected to the tube section (12) respectively and are arranged adjacent to coolant ports (15, 18), and to which busbars (06) can be connected respectively.

2. The current lead (11) according to claim 1, wherein the specific resistance of the material of the tube section (12) is at least 0.25 μΩm; or wherein the specific resistance of the material of the tube section (12) is at least 0.5 μΩm.

3. The current lead (11) according to claim 1 or 2, The current conduit comprises a main terminal (04) as a current terminal at at least one end portion; and / or the current lead comprises supply ports (17, 18) as coolant ports at at least one end; and / or the current lead comprises at least two current terminals (16) which are spaced apart from one another and from the ends and at least two coolant ports (15) which are spaced apart from the ends.

4. The current lead (11) according to claim 1 or 2, the current lead comprises a first tube section (12) and at least one second tube section (12) and an expansion compensation mechanism arranged between the tube sections (12).

5. The current lead according to claim 4, wherein the expansion compensation mechanism is formed by an electrically conductive and coolant-conducting bellows or U-shaped or meandering tube stretch.

6. The current lead (11) according to claim 4, wherein the expansion compensation mechanism comprises a coolant-conducting bellows (13) or compensator and an electrically conductive bridge (14) which connects the adjoining ends of the tube sections (12) to one another.

7. The current lead (11) according to claim 1 or 2, wherein the specific resistance of the material of the current terminals (16) is at most 0.05 μΩm; or wherein the specific resistance of the material of the current terminals (16) is at most 0.025 μΩm.

8. A current transformer device (01) comprising a first current lead (11+) and a second current lead (11-) respectively embodied according to any one of the preceding claims and at least one current transformer (02) which is connected to the current terminals (16) of the two current leads (11+, 11-) respectively via electrically conductive busbars (06) and to the coolant ports (15) of the two current leads respectively via non-electrically conductive coolant tubes (05).

9. The current transformer device (01) according to claim 8, The converter device comprises at least two converters (02) which are connected on the current conductors (11+, 11-).

10. Converter device (01) according to claim 8 or 9, The converter device comprises a coolant supply device (03) which is connected on a first supply port (17+) by means of a first, electrically non-conducting port tube (07+) and on a second supply port (17-) by means of a second, electrically non-conducting port tube (07-).

11. Converter device (01) according to claim 10, wherein the coolant supply device (03) has a coolant pump and a cooling device.

12. Converter device (01) according to claim 10, The converter device comprises electrically non-conducting connection tubes (08) which are connected on supply ports (18+, 18-) in a coolant-conducting manner, which supply ports are opposite to the ports to the coolant supply device (03).

13. Converter device (01) according to claim 8 or 9, The converter device comprises at least one capacitor which is connected on further current terminals (16+, 16-) of the two current conductors (11+, 11-).

14. Converter device (01) according to claim 8 or 9, The converter device comprises a DC voltage network which is connected on main terminals of the two current conductors as current terminals, and on which a consumer is connected in turn.

15. Converter device (01) according to claim 8, The converter device comprises at least three converters (02) which are connected on the current conductors (11+, 11-).

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