LU500997B1 - Short-circuit protection for a converter - Google Patents

Abstract

The invention relates, among other things, to a converter (100) for connecting an electrical load (1) to an energy supply network (2), having a line-side converter (10) and a load-side converter (20), the line-side converter (10) and the load-side Power converters (20) are electrically conductively connected to one another via a DC link (30). The invention is characterized in that the DC voltage intermediate circuit (30) has at least one short-circuiting device (40, 50), the at least one short-circuiting device (40, 50) being designed by a short-circuit current in the DC voltage intermediate 10 schenkreis (30) automatically form at least one electrically conductive connection for diverting the short-circuit current. The invention also relates to the use of such a converter (100) for connecting an electrical load (1) to an energy supply network (2).

Description

Short-circuit protection for a drive LU500997

The invention relates to a converter for connecting an electrical load to a power supply network, the converter comprising a short-circuiting device. Furthermore, the invention relates to the use of such a converter for connecting an electrical load to a

power grid.

For reasons of electrical safety, protection against short circuits is usually required for mains applications. Usually this current-limiting switching elements such. B.

fuses and/or circuit breakers used. Critical parameters for these switching elements are often the forward current (peak value of the current that flows before switching off) and/or the tripping energy required (e.g. melting integral of a fuse, i.e. the

energy necessary to bring about the shutdown). The requirements for the corresponding sizes depend on the connection values of the supply network, the

switching element, the connected impedance, which is effective despite a short circuit (network impedance,

line impedance, etc.) and the other elements that must carry the short-circuit current.

A frequent problem when using the aforementioned current-limiting switching elements is that for a downstream switching element (z. B. contactor, motor switching device o. à.) The permissible

parameters could be exceeded and therefore smaller fuses must be selected. In the case of circuits with high peak currents (e.g. starting currents of motors), this leads to a design conflict. Furthermore, many current-limiting switching elements can only increase too slowly

Switch off short-circuit currents so that excessive currents may flow through the downstream elements, which can cause damage there.

Last but not least, this problem is relevant for frequency converters, especially since the requirements for short-circuit strength have increased there. This is the case with frequency converters in the

Usually no internal protection against short circuits in the intermediate circuit, e.g. B. due to insulation damage and / or a defect in the intermediate circuit capacitor provided. Corresponding short-circuit tests show that such faults in the intermediate circuit with a relatively slow short-circuit protection (e.g. a circuit breaker) have massive effects and the resulting

Pressure wave can even lead to the opening of a control cabinet door. Consequently, there is a need for a solution by means of which the operational reliability of a converter, preferably a frequency converter, can be increased.

The object of the invention is therefore to provide such a solution, with preference also being given to LU500997

Disadvantages of previous approaches should be avoided. In particular, it is a task of

Invention to provide a fast and reliable short-circuit protection in the converter, by means of which the release of energy to the outside can be avoided as much as possible in the event of a fault.

These objects can be solved with the features of the independent claims. Advantageous embodiments and applications of the invention are the subject matter of the dependent claims and are explained in more detail in the following description with partial reference to the figures.

According to a first independent aspect, a converter, preferably a frequency converter, is provided. The converter preferably serves to connect an electrical load (eg an electric motor) to a (eg single-phase or multi-phase) power supply network. The converter, preferably capable of regenerative feedback, has a first converter which, for better differentiation, can also be referred to below as a line-side converter. The grid-side power converter can be used for connection to the power supply grid and/or can include one or more inputs for connection to the power supply grid.

Furthermore, the line-side power converter can be designed as a rectifier (for example as a diode rectifier) which converts a line-side AC voltage into a DC voltage. Alternatively, the grid-side power converter can also be designed as a direct-current converter.

Furthermore, the converter includes a further converter, which can be referred to below as a second or load-side converter for better differentiation. The load-side converter can serve to connect to the load and / or one or more inputs to

include connection to the load. The power converter on the load side should preferably be in the form of a preferably self-commutated inverter (eg an IGBT inverter), which converts a DC voltage into an AC voltage on the load side. However, the load-side power converter can alternatively be in the form of a direct-current chopper.

Furthermore, the converter includes a direct voltage intermediate circuit. The mains-side converter and the load-side converter are electrically conductively connected to one another via the DC link. For example, the DC link can include a first circuit branch (DC+) and a second circuit branch (DC-). The first

Circuit branch (DC+) can have a positive DC voltage-side connection of the line-side

LU500997 connect the power converter to a positive DC-side connection of the load-side converter, while the second circuit branch (DC-) connects a negative DC-side connection of the line-side converter to a negative DC-side connection of the load-side converter. The DC voltage intermediate circuit preferably also has one or more intermediate circuit capacitors for smoothing the voltage im

intermediate circuit on. For example, the DC voltage intermediate circuit can include a plurality of intermediate circuit capacitors connected in parallel and/or in series.

The converter is characterized in that the DC link has at least one short-circuiting device. This at least one short-circuiting device is designed to automatically form at least one electrically conductive connection as a result of a short-circuit current in the DC voltage intermediate circuit (e.g. as a result of a defect in an intermediate circuit capacitor), with the at least one electrically conductive connection preferably being used for rerouting and / or re-channelling of the short-circuit current is used. Preferably, the at least short-circuit

The device can therefore be designed to provide an additional current path for the short-circuit current if there is a short-circuit current in the DC voltage intermediate circuit (e.g. to derive it from the converter into the power supply network), without external intervention being necessary for this. In other words, the (additional) electrically conductive connection (mediated by the short-circuit current) can be formed automatically. As will be explained in more detail below, this can e.g. B. by means of a predefined (initially isolating)

planned breakdown point, d. H. a predefined weakening of the circuit, which becomes conductive as a result of the short-circuit current (bypass). Advantageously, this can automatically shift the current via the newly formed conductive connection or the newly created current path in such a way that, to protect the components of the converter, the fault current is taken over from the intermediate circuit and fed to a suitable point ( z. B. back to the power supply network) is derived.

According to a first aspect, the at least one short-circuiting device can have a first short-circuiting device, which can also be referred to below as the first auxiliary short-circuit.

In this case, the first short-circuiting device can comprise a first conductor and a second conductor, it being possible for the second conductor to be electrically insulated from the first conductor (eg by an insulating circuit board material). Furthermore, the first conductor can have a line constriction (eg in the form of a section-wise narrowing of the first conductor), which can be referred to below as the first line constriction or first ignition electrode. The first line constriction can be designed in such a way and the second conductor can also be routed past the first line constriction of the first conductor in such a way that a line constriction between the first line constriction and the second LU500997

Conductor existing insulation layer (z. B. a plastic such as polyurethane and / or a glass fiber reinforced plastic such as FR4) is destroyed in a short-circuit current through the first conductor, preferably thermally, so that the aforementioned at least one electrically conductive connection between between the first conductor and the second conductor. The first short-circuiting device is preferably designed such that in the event of a short-circuit current via the first conductor, a targeted thermal load is induced at the first line constriction (ignition electrode). The first conductor or the adjoining insulation layer can be destructible as a result of this local (high) excess temperature in the area of the first line constriction, with the formation of a plasma channel, so that crosstalk to the adjoining second conductor is made possible. With others

Words should preferably be a deliberate (local) damage to the circuit to form an additional current path, which is why the first short-circuiting device as the first target

Breakthrough point can be designated. Advantageously, this can (in the event of a short circuit) automatically allow a current shift via the newly formed or specifically created electrically conductive connection, such that the second conductor removes the fault current from the

Intermediate circuit takes over and derives it at a suitable point (e.g. back into the power supply network), so that components downstream of the first short-circuiting device are preferably not loaded by the short-circuit current. It is particularly advantageous that the formation of the additional current path requires only a few milliseconds (cf. FIG. 6) and thus switches significantly faster than a power circuit breaker that is preferably additionally present (typically 10-20 ms).

According to a further aspect, the first conductor and/or the second conductor can be arranged at least in sections in a wavy and/or zigzag shape and/or in a meandering shape, preferably in a sharp-edged meandering shape. Preferably, the first line constriction of the first conductor and/or an end area of the second conductor can be arranged at least in sections in a wavy and/or zigzag shape and/or (sharp-edged) meander shape. The aforementioned embodiments make it possible in an advantageous manner to accommodate the longest possible short-circuiting device in a small space. Furthermore, the tips of the aforementioned structures advantageously allow a high field concentration and thus a deliberate weakening of the insulation or insulation layer there.

In addition or as an alternative, the first conductor and the second conductor can also be arranged parallel to one another, at least in sections. i.e. the first and second conductors can thus preferably run next to one another at the same distance in the case of the first short-circuiting device or in the case of the first line constriction. An end region of the second conductor is preferably arranged at least in sections parallel to the first line constriction of the first conductor. In a merely exemplary embodiment, e.g. B. the first and second conductors each have the same zigzag

Zack progression, the corresponding progressions being shifted (e.g. plane-parallel) or offset from one another in such a way that the first and second conductors always run at a fixed distance from one another in this area. In an alternative embodiment, the second conductor can also be T-shaped in its end region, with the crossbar of the T

Shape can be arranged running parallel to the first conductor or the first line constriction.

In this way, an extended desired breakdown point can be provided in an advantageous manner.

In addition or as an alternative, the first conductor and the second conductor can also have at least one, preferably several, changes in direction. i.e. the first and second conductors can thus preferably change their course or direction once or several times in the case of the first short-circuiting device or in the case of the first line constriction. In this case, the first line constriction of the first conductor and/or an end region of the second conductor can preferably have at least one, preferably several, changes in direction. Merely by way of example, the first and second

conductor e.g. B. be arranged in a zigzag shape, with other direction-changing geometries are possible. This variant also makes it possible in an advantageous manner to accommodate the longest possible short-circuiting device in a small space.

According to a further aspect, the insulation layer present between the first line constriction and the second conductor can be heatable by a current flow through the first line constriction. i.e. the insulation layer can thus be thermally coupled to the first conductor or the first line constriction in order to absorb heat from the first line constriction, particularly in the event of a short circuit. In addition or as an alternative, the insulation layer (eg a plastic) can also be designed to melt and/or evaporate when a predetermined temperature is reached. A time interval can preferably be set via the material of the insulation layer and/or via the extent, in particular thickness, of the insulation layer until the insulation layer reaches the predetermined temperature or is destroyed and thus also a time interval until the short-circuiting device ( A combination of material and geometry of the insulation layer or geometry of the short-circuiting device that is suitable for the specific application can be determined by a person skilled in the art, e.g. B. by appropriate preliminary tests (short-circuit tests). Overall, the breakdown properties of the short-circuiting device can be set or specified in an advantageous manner.

According to a further aspect, the second conductor can have a line constriction, which can be referred to below as the second line constriction for better differentiation. In other words, both the first conductor can have a (first) line constriction and the second conductor can have a (second) line constriction. The second line constriction is preferably arranged in an end region (eg at a distal end) of the second conductor. The expression “line constriction” can preferably mean a narrowing or narrowing of the respective

be understood conductor cross-section, d. H. a conscious (local) reduction of the geometric

Dimensions of the respective conductor. Furthermore, the second line constriction of the second conductor can be arranged adjacent to the first line constriction of the first conductor. The first and second line constriction can thus, preferably close together and / or in the immediate

be arranged near. The first and second line bottlenecks are thus preferably only separated from one another by the aforementioned insulation layer. By appropriately providing two adjacent line constrictions, crosstalk or the formation of a conductive connection between the first and second conductors can be set in an advantageous manner.

According to a further aspect, the DC voltage intermediate circuit can have a circuit branch which connects the line-side converter and the load-side converter to one another (electrically conductive), the corresponding circuit branch being referred to below as the first circuit branch for better differentiation. The first circuit branch (e.g. in the form of a strip conductor or conductor rail) can connect a positive DC voltage-side connection of the grid-side converter to a positive DC voltage-side connection of the load-side converter (DC+) purely by way of example. Alternatively, the first

Circuit branch also connect a negative DC voltage-side connection of the mains-side converter to a negative DC voltage-side connection of the load-side converter (DC-). Furthermore, the first conductor of the first short-circuiting device can be arranged in the first circuit branch or in front of the first circuit branch. i.e. the first conductor or the first line constriction can preferably be a (partial) section of the first circuit branch. For example, a first end of the first conductor or the first line constriction (e.g. via a

Conductor section of the first circuit branch) be electrically conductively connected to the line-side converter and/or a second end of the first conductor or the first line constriction (e.g. via another conductor section of the first circuit branch) be electrically conductively connected to the load-side converter . Advantageously, if the LU500997

DC voltage intermediate circuit by a response of the first short-circuiting device

Current shift from the intermediate circuit can be made possible.

According to a further aspect, the DC voltage intermediate circuit can have a further circuit branch, which can be referred to below as the second circuit branch. The DC voltage intermediate circuit thus preferably comprises two circuit branches. Like the aforementioned first circuit branch, the second circuit branch can also connect the line-side converter and the load-side converter to one another (electrically conductive). Merely as an example, z. For example, the first circuit branch has a positive DC voltage-side connection of the line-side converter with a positive DC voltage-side connection of the load side

Connect the converter while z. B. the second circuit branch (e.g. in the form of a strip conductor or conductor rail) can connect a negative DC voltage-side connection of the line-side converter to a negative DC voltage-side connection of the load-side converter. Furthermore, the second conductor of the first short-circuiting device can be arranged in the second circuit branch or in front of the second circuit branch. i.e. the second conductor can preferably be a (partial) section of the second circuit branch. For example, a first

End of the second conductor or the second line constriction (e.g. via a conductor section of the second

Circuit branch) to be electrically conductively connected to the line-side converter and / or a second end of the second conductor or the second line constriction (z. B. via another

Conductor section of the second circuit branch) to be electrically conductively connected to the load-side converter. The first conductor and the second conductor are therefore preferably located in different circuit branches of the DC link, i. H. e.g. B. the first conductor in the first circuit branch and the second conductor in the second circuit branch. On advantageous

In this way, in the event of a fault, a targeted connection between the circuit branches of the

DC link circuit are made possible in order to separate subsequent components from the current flow.

According to a further aspect, the grid-side converter can have a first grid connection

Have connection to the power supply network, the first network connection, which can also be referred to as the first network-side input of the network-side power converter, z. B. for connecting to a (first) phase (z. B. L1) of a three-phase power supply network. For this purpose, the first mains connection can e.g. B. one or more contact elements (e.g.

Screw, spring force and/or insulation displacement contacts) for connecting a conductor of the energy supply network. Furthermore, the second conductor of the first short-circuiting device can be connected (electrically conductive) to the aforementioned first network connection of the network-side converter. For example, the second conductor can be connected to the first mains connection via a corresponding connecting line (e.g. in the form of a conductor track). On advantageous

As a result, the current can be shifted or the short-circuit current diverted to the input of the line-side converter, as a result of which the energy can be routed past the line-side converter, in particular any diodes that may be present there.

In order to advantageously further increase the short-circuit protection of the converter, the

According to a further aspect, the DC voltage intermediate circuit has a further short-circuiting device. For better differentiation from the aforementioned "first" short-circuiting device, this (additional) short-circuiting device can be referred to below as the "second" short-circuiting device. The second short-circuiting device can preferably be identical to the first

Be constructed short-circuiting device, the corresponding components for better distinguishability are referenced differently below. Thus, the second short-circuiting device can in particular comprise a third conductor and a fourth conductor, the fourth

Conductor from the third conductor (z. B. by an insulating circuit board material) may be electrically isolated. Furthermore, the third conductor can have a line constriction (e.g. in the form of a section-wise narrowing of the first conductor), which, in order to distinguish it from the aforementioned “first” or “second” line constrictions of the first short-circuiting device, is designated as a “third” line constriction. can be drawn. Furthermore, the third line constriction can be designed in such a way and the fourth conductor can be routed past the third line constriction of the third conductor in such a way that an additional insulating layer (e.g. a plastic such as polyurethane) between the third line constriction and the fourth conductor can Short-circuit current through the third conductor, preferably thermally, is destroyed, so that the aforementioned at least one electrically conductive

Connection between the third conductor and the fourth conductor is present. Analogously to the first short-circuiting device, the second short-circuiting device can also be preferably designed such that in

In the event of a short-circuit current via the third conductor, a targeted thermal load is induced at the third cable constriction (ignition electrode). The third conductor or the adjacent further insulation layer can as a result of this local (high) excess temperature in the area

Line constriction can be destroyed with the formation of a plasma channel, so that crosstalk to the adjoining fourth conductor is made possible.

Current shift via the newly formed or specifically created current path of the second

Short-circuiting device are made possible.

According to a development of this aspect, the third conductor of the second short-circuiting device LU500997—in addition to or as an alternative to the second conductor of the first short-circuiting device—can be arranged in the aforementioned second circuit branch of the DC voltage intermediate circuit. As has already been explained above, the second circuit branch can connect the mains-side converter and the load-side converter to one another (electrically conductive). For example, the second branch of the circuit (e.g. in the form of a strip conductor or conductor rail) can connect a negative DC voltage-side connection of the line-side converter to a negative DC voltage-side connection of the load-side converter, while z. B. the first

Circuit branch can connect a positive DC voltage-side connection of the line-side converter with a positive DC voltage-side connection of the load-side converter. The third conductor of the second short-circuiting device can preferably also be a (partial) section of the second circuit branch. For example, a first end of the third conductor or the third line constriction can be electrically conductively connected to the line-side power converter (e.g. via a conductor piece of the second circuit branch) and/or a second end of the third

Head or the third line constriction (z. B. via another conductor piece of the second circuit branch) to be electrically conductively connected to the load-side power converter.

According to a further aspect, the grid-side converter can have a second grid connection

Have connect to the power supply network. The second mains connection, which can also be referred to as the second mains-side input of the mains-side converter, can, for. B. for connection to a (second) phase (z. B. L3) be formed of a three-phase power supply network. For this purpose, the second mains connection can e.g. B. include one or more contact elements (z. B. screw, spring and / or insulation displacement contacts) for connecting a conductor of the energy supply network. Furthermore, the fourth conductor of the second short-circuiting device can be connected (electrically conductive) to the aforementioned second network connection of the network-side power converter. For example, the fourth conductor can be connected to the second mains connection via a corresponding connecting line (eg in the form of a conductor track). Advantageously, a (further) current transfer or derivation of the short-circuit current to the input of the grid-side converter can take place, whereby the energy can be routed past the grid-side converter, in particular any diodes that may be present there.

According to a further aspect, the fourth conductor of the second short-circuiting device can be connected (electrically conductive) to the second conductor of the first short-circuiting device via a preferably potential-free connecting line. i.e. the converter can include a preferably potential-free connecting line (e.g. in the form of a conductor track) via which the first and second

Short-circuiting device are connected to each other. For example, a first (distal) end of the connecting line can be connected to the second conductor of the first short-circuiting device and/or a second (distal) end of the connecting line can be connected to the fourth conductor of the second short-circuiting device. Advantageously, this allows the two short-circuiting devices to be brought together in order to separate subsequent components from the current flow in the event of a fault.

According to a further aspect - analogous to the embodiment variants of the first short-

Device - the third and fourth conductors of the second short-circuiting device can be arranged at least in sections in a wavy, zigzag and/or meandering pattern, preferably in a sharp-edged meandering pattern. The third line constriction of the third conductor and/or an end region of the fourth conductor can preferably be arranged in a wavy and/or zigzag shape and/or (sharp-edged) meander shape, at least in sections. This kind of

Execution in turn makes it possible in an advantageous manner to accommodate the longest possible short-circuiting device in a small space. Furthermore, the tips of the aforementioned allow

Structures advantageously have a high field concentration and thus a deliberate weakening of the local insulation or insulation layer.

In addition or as an alternative, the third conductor and the fourth conductor of the second short-circuiting device can be arranged parallel to one another, at least in sections. i.e. the third and fourth

Conductors can thus preferably run side by side at the same distance at the second short-circuiting device or at the third line constriction. An end region of the fourth conductor is preferably arranged at least in sections parallel to the third line constriction of the third conductor. The fourth conductor can be designed in a T-shape in its end region, purely by way of example, with the crossbar of the T-shape being able to be arranged running parallel to the third conductor or the third line constriction. Advantageously, this allows an extensive

Target breakthrough point are provided.

In addition or as an alternative, the third conductor and the fourth conductor of the second short-circuiting device can also have at least one, preferably several, changes in direction. i.e. the third and fourth conductors can thus in the second short-circuiting device or in the third

Line bottlenecks preferably change their course or direction one or more times. In this case, the third line constriction of the third conductor and/or an end region of the fourth conductor can preferably have at least one, preferably several, changes in direction. For example, the third and fourth conductors can be e.g. B. be arranged in a meandering shape, with other direction-changing geometries are possible. This variant also allows for advantageous LU500997

Way to accommodate the longest possible short-circuiting device in a small space.

In addition or as an alternative, the further (between the third line constriction and the fourth

Conductor existing) insulation layer can be heated by a current flow through the third line constriction. i.e. the further insulating layer can thus be connected to the third conductor or the third

Line constriction be thermally coupled to absorb heat from the third line constriction, especially in the event of a short circuit. In addition or as an alternative, the further insulating layer (e.g. a plastic) can also be designed to melt and/or evaporate when a predetermined temperature is reached. Preferably, the material of the further insulation layer and/or the extent, in particular the thickness, of the further insulation layer can be used

Time interval can be set until the further insulation layer reaches the predetermined temperature or is destroyed and thus also a time interval until the second short-circuiting device (e.g. by

Flashover, or arc) becomes electrically conductive. With regard to the time interval or the breakdown properties, the second short-circuiting device can be designed identically to the first short-circuiting device. Alternatively, however, the two short-circuiting devices can also be designed differently.

In addition or as an alternative, the fourth conductor can also have a line constriction, which can be referred to below as the fourth line constriction for better differentiation. In other words, in the case of the second short-circuiting device, both the third conductor can have a (third) line constriction and the fourth conductor can have a (fourth) line constriction. The fourth line constriction is preferably in an end region (eg at a distal end) of the fourth

conductor arranged. Furthermore, the fourth line constriction of the fourth conductor can be arranged adjacent to the third line constriction of the third conductor. The third and fourth line constriction can thus be arranged, preferably close together and/or in the immediate vicinity. The third and fourth line bottlenecks are thus preferably only separated from one another by the aforementioned further insulation layer. By appropriately providing two adjacent line constrictions, crosstalk or the formation of a conductive connection between the third and fourth conductors can be set in an advantageous manner.

According to a further aspect, the first and/or the second short-circuiting device can be arranged within a printed circuit board. Additionally or alternatively, the first and/or the second short

locking device can also be arranged between two printed circuit boards fastened to one another. It is preferably provided that all the cables of the converter are routed in an inner layer of a printed circuit board. Arranging the conductors accordingly, and in particular the first and/or second

The short-circuiting device within the printed circuit board has the advantage that the energy released in the event of a short circuit is released as far as possible within the printed circuit board and thus not on another surface. A plasma cloud on the surface of the circuit board, which z. B. with regard to contact protection and components flying around as a result of a pressure surge would represent a safety risk can thus be effectively avoided.

According to a further aspect, the grid-side converter can be a three-phase converter. The grid-side power converter can thus have at least three grid connections on the grid side,

The mains connections can be used and/or designed to connect one phase of a three-phase power supply network. In addition or as an alternative, the load-side converter can also be a three-phase converter. Correspondingly, the load-side power converter can have at least three load terminals on the load side. The load terminals can be used and/or designed to connect one phase of a three-phase load (e.g. one phase of a three-phase asynchronous motor).

According to a further aspect, the DC voltage intermediate circuit can have an intermediate circuit capacitor. The intermediate circuit capacitor is preferably used to compensate for line inductances or to smooth the voltage in the DC voltage intermediate circuit. Furthermore, the first and second circuit branches can be electrically coupled via the aforementioned intermediate circuit capacitor. For example, one electrode of the intermediate circuit capacitor can be connected to the first circuit branch (electrically conductive), while a second electrode of the intermediate circuit capacitor can be connected to the second circuit branch (electrically conductive).

According to a further independent aspect, use of a converter, as described in this document, is provided for connecting an electrical load (eg an electric motor) to an energy supply network. The features described in connection with the converter should also be used in connection shall be deemed disclosed and claimable with its use. The same should also apply vice versa. The use of the converter includes a preferably automatic formation of at least one electrically conductive connection by means of the at least one short-circuiting device of the converter by a short-circuit

short-circuit current in the DC link. i.e. preferably, as a result of the short-circuit LU500997 current or mediated by the short-circuit current, a preferably automatic formation of a new or additional current path can take place, this preferably being used to divert the

Short-circuit current is used.

If the at least one short-circuiting device includes the aforementioned first short-circuiting device, the use can also include destroying, preferably thermally, the insulation layer present between the first line constriction and the second conductor in the event of a short-circuit current via the first conductor, so that a there is an electrically conductive connection between the first and second conductors. Preferably, the insulation layer between the first line constriction and the second conductor can be heated by a current flow through the first line constriction, wherein the insulation layer (eg a plastic) can be designed to melt when a predetermined temperature is reached and/or to evaporate. In other words, in the case of a short-circuit current, the use can include a targeted induction of a thermal load at the first line constriction in order to thereby melt and/or vaporize the insulating layer, so that the first and second

Conductor (z. B. by sparking or arcing) are electrically connected. In the

If the converter also includes an aforementioned second short-circuit device, the use can also or alternatively also involve, preferably thermal, destruction of the further insulation layer present between the third line constriction and the fourth conductor in the event of a short-circuit current via the third conductor, so that a there is an electrically conductive connection between the third and fourth conductors.

The aspects and features of the invention described above can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings. Show it:

FIG. 1: a schematic representation of a converter according to a first embodiment;

FIG. 2: a schematic representation of a converter according to a second embodiment;

FIG. 3: a schematic representation of a converter according to a third embodiment;

FIG. 4: a schematic detailed representation of a short-circuiting device according to one embodiment;

FIG. 5: a schematic sectional view of one embedded in a printed circuit board

Short-circuiting device according to one embodiment;

FIG. 6: example of a short-circuit current over time within a converter with a short-circuiting device according to one embodiment.

Identical or functionally equivalent elements are described with the same reference symbols in all figures and some of them are not described separately.

FIG. 1 shows a schematic representation of a converter 100 according to a first embodiment. H. a device for converting a fed-in AC voltage into another AC voltage (e.g. with a different frequency and/or amplitude). The converter 100, which e.g. B. can be encased by a housing 101, can preferably be used to connect an electrical load 1, for example in the form of an electric motor, to a power supply network 2, wherein the power supply network 2 is present - just as an example - a three-phase power supply network can act. The preferably regenerative

In this case, converter 100 has a line-side converter 10 . The line-side power converter 10 can be used for connection to the power supply system 2 and can accordingly include one or more connections, in the present example three connections 11 , 12 and 13 , for connection to the power supply system 2 . By way of example only, the line-side converter 10 z. B. be designed as a diode rectifier, which is set up to convert a mains-side AC voltage into a DC voltage.

Furthermore, the converter 100 includes a further load-side power converter 20. The load-side

Power converter 20 can be used for connection to the load 1 and accordingly one or more

Connections, in this case three connections 21, 22 and 23, for connection to the load 2 include. For example, the load-side power converter 20 can be used as a preferably self-commutated

Inverter (e.g. an IGBT inverter) that is designed to convert a DC voltage into an AC voltage on the load side,

Furthermore, the converter 100 has a direct voltage intermediate circuit 30 . The mains-side converter 10 and the load-side converter 20 are electrically conductively connected to one another via the DC link 30 . For this purpose, the DC voltage intermediate circuit 30 can comprise a first circuit branch 31 and a second circuit branch 32 purely by way of example. The first circuit branch 31 can connect a positive DC voltage-side connection of the grid-side converter 10 to a positive DC voltage-side connection of the load-side converter 20, while the second circuit branch 32 can connect a negative DC voltage-side connection of the grid-side converter 10 to a negative DC voltage-side connection of the load-side converter 20 can connect. Preferably, the

DC voltage intermediate circuit 30 also has an intermediate circuit capacitor 33 for smoothing the

Voltage in the DC link 30 on. Here, the intermediate circuit capacitor 33 shown can be understood as an equivalent circuit diagram for any intermediate circuit capacitance, so that the DC voltage intermediate circuit 30 z. B. also several, z. B. parallel! and/or intermediate circuit capacitors 33 connected in series. The intermediate circuit capacitor 33 can z. B. the first and second circuit branch 31, 32 electrically couple to each other.

In order to advantageously provide rapid and safe short-circuit protection in the converter 100 or in the DC link 30, the DC link 30 also has at least one short-circuiting device, with the present exemplary embodiment only having a (first) short-circuiting device 40 includes. The at least one short-circuiting device 40 preferably serves to form an additional current path in the event of a fault.

This can be z. B. be one of the following exemplary error cases: an internal

Short circuit (z. B. a diode) in the line-side power converter 10, a defective component in the load side

Converter 20 (e.g. a defect in an IGBT circuit), a short circuit in the intermediate circuit capacitor - capacitor 33, a general insulation fault in the DC intermediate circuit 30 and/or a

Insulation fault in the DC link 30 due to external influences (e.g. due to moisture, dust or metal shavings). The at least one short-circuiting device is designed to be triggered by a short-circuit current in the DC voltage intermediate circuit 30 (e.g. as a result of one of the aforementioned

Cases) automatically form at least one (additional) electrically conductive connection, the at least one electrically conductive connection preferably serving to redirect and/or re-channel the short-circuit current.

As shown here, the at least one short-circuiting device can have a first

Include short-circuiting device 40, the exemplary structure of which will be described in more detail in connection with FIG. The first short-circuiting device 40 can include a first conductor 41 and a second conductor 42 . The second conductor can be electrically insulated from the first conductor 41 (e.g. by an insulating circuit board material). Furthermore, the first conductor 41 can have a first line constriction 43 (eg in the form of a sectional narrowing of the first conductor 41). In the present case, the first line constriction 43 is merely embodied in a zigzag shape, ie. H. the first conductor 41 runs there in a zigzag line with several changes of direction. The corresponding peaks advantageously allow a high field concentration and thus a deliberate weakening of the insulation there. The first line constriction (43) can also be designed in such a way and the second conductor 42 can also be routed past the first line constriction 43 of the first conductor 41 (cf. e.g. Figure 4) such that a line constriction 43 and the second Conductor 42 existing insulation layer 44 (z. B. a plastic such as polyurethane) is destroyed in a short-circuit current through the first conductor 41, preferably thermally, so that the aforementioned at least one electrically conductive connection between the first conductor 41 and the second

Head 42 is present.

In the event of a short circuit, deliberate (local) damage to the first short-circuiting device 40 should preferably take place in order to form an additional current path, which is why the first short-circuiting

Beinrichtung 40 can also be referred to as a target breakdown point. For this purpose, the second conductor 42 preferably also has a line constriction 45 (e.g. also designed in a zigzag shape), which should be referred to as the “second” line constriction 45 for better differentiation. As shown here by way of example, the second line constriction 45 can be arranged in an end area of the second conductor 42 and/or can be arranged adjacent to the first line constriction 43 of the first conductor 41 . The first and second line bottlenecks 43, 45 can thus be arranged, preferably close together, and/or in the immediate vicinity and only be separated from one another by the preferably thin insulating layer 44. This can, as already described above, automatically in an advantageous manner in the event of a short circuit

Current displacement via the second conductor 42, which is then connected to the first conductor 41, is made possible in such a way that this second conductor 42 absorbs the fault current from the DC voltage

Intermediate circuit 30 takes over and diverts it to a suitable point, which will be described in more detail below. Since the formation of the additional current path requires only a few milliseconds (see FIG. 6) and is therefore significantly faster than a circuit breaker that is preferably additionally present (typically 10-20 ms), a faster and reliable short-circuit protection for the converter 100 can be provided.

After the basic functioning of the first short-circuiting device 40 has been described above, the specific arrangement of the first short-circuiting device 40 in the DC voltage intermediate circuit 30 will be discussed below. According to the exemplary embodiment shown, the first conductor 41 of the first short-circuiting device 40 can be arranged in the first circuit branch 31 of the DC link 30 . i.e. the first conductor 41 can thus preferably be designed as a (partial) section of the first circuit branch 31 . For example, a first end of the first conductor 41 or the first line constriction 43 can be connected via a (first) conductor section 31a of the first circuit branch 31 to the mains-side

Converter 10 be electrically conductively connected and a second end of the first conductor 41 or the first line constriction 43 via a (second) conductor piece 31b of the first circuit branch 31 with the load-side converter 20 be electrically conductively connected. Furthermore, according to the present exemplary embodiment, the second conductor 42 of the first short-circuiting device 40 can be arranged in the second circuit branch 32 of the DC voltage intermediate circuit 30 . i.e. the second conductor 42 can thus preferably be embodied as a (partial) section of the second circuit branch 32-. For example, to a first end of the second conductor 42 or the second

Line constriction 45 via a (first) conductor piece 32a of the second circuit branch 32 to be electrically conductively connected to the line-side power converter 10 and a second end of the second

Conductor 42 and the second line constriction 45 via a (second) conductor section 32b of the second

Circuit branch 32 can be electrically connected to the load-side converter 20 . Advantageously, in the event of a fault, a targeted connection between the circuit branches 31 and 32 of the DC voltage intermediate circuit 30 can be made possible in order to separate subsequent components from the current flow.

FIG. 2 shows a schematic representation of a converter 100 according to a second specific embodiment. The basic structure of the converter 100, consisting of a line-side converter 10 and a load-side converter 20, which are electrically conductively connected via a DC voltage intermediate circuit 30, is identical to the embodiment described above.

However, the connection/arrangement of the first short-circuiting device 40 differs in the present exemplary embodiment. According to this variant, the first conductor 41 of the first short-circuiting device 40 can in turn be in the first circuit branch 31 of the

DC link circuit 30 may be arranged. That is, the first conductor 41 or the first line constriction 43 can, for. B. by means of a first conductor piece 31a of the first circuit branch 31 with the line-side power converter 10 and by means of a second

Conductor piece 31b of the first circuit branch 31 can be electrically conductively connected to the load-side converter 20 . The second conductor 42 or the second line constriction 45 of the first short-circuiting device 40 is LU500997 in the present example, however (via a conductor section 46) with the first

Mains connection 11 of the mains-side power converter 10 is electrically connected. On advantageous

In the event of a fault, this can result in a current shift or derivation of the short-circuit current to the input of the line-side converter 10, so that the energy can be routed past the line-side converter 10, in particular to any diodes that may be present there.

In addition to the first short-circuiting device 40 described above, the DC voltage intermediate circuit 30 in the exemplary embodiment shown has a further (second)

Short-circuiting device 50 on. This second short-circuiting device 50 can (as shown by way of example) be designed in principle identical to the first short-circuiting device 40 in terms of its basic structure, with the corresponding components being referenced differently, however, for better differentiation.

Thus, the second short-circuiting device 50 can comprise a third conductor 51 and a fourth conductor 52, it being possible for the fourth conductor 52 to be electrically insulated from the third conductor 51 (eg by an insulating printed circuit board material). Furthermore, the third conductor 51 can have a “third” line constriction 53 (eg in the form of a sectional narrowing of the first conductor). In the present case, the third line constriction 53 is again designed—just by way of example—in a zigzag shape.

The third line constriction 53 can be designed in such a way, and the fourth conductor 52 can be routed past the third line constriction 53 of the third conductor 51, in such a way that an additional insulation layer 54 (e.g.

B. a plastic such as polyurethane) in a short-circuit current through the third conductor 51, preferably thermally, is destroyed, so that an electrically conductive connection between the third

Conductor 51 and the fourth conductor 52 is present.

As shown by way of example, the fourth conductor 52 can also in turn have a fourth line constriction 55 (e.g. likewise embodied in a zigzag shape). As shown here, this can be arranged in an end region of the fourth conductor 52 and/or arranged adjacent to the third line constriction 53 of the third conductor 51 . The third and fourth line bottlenecks 53, 55 can thus be arranged, preferably close together, and/or in the immediate vicinity and only be separated from one another by the preferably thin further insulating layer 54. As has already been described above for the first short-circuiting device 40, the second short-circuiting device 50 can also be advantageous

In the event of a short circuit, a further current path for dissipating the short circuit current LU500997 is automatically formed.

In the present case, it is provided, for example, that a short-circuit current can also be discharged to the input of the line-side converter 10 by means of the second short-circuiting device 50 . For this purpose, the third conductor 51 of the second short-circuiting device 50 can be arranged in the second circuit branch 32 of the DC voltage intermediate circuit 30 . i.e. the third conductor 51 can thus preferably be embodied as a (partial) section of the second circuit branch 32 . For example, a first end of the third conductor 51 or the third line constriction 53 can be electrically conductively connected to the line-side converter 10 via a (first) conductor piece 32a of the second circuit branch 32 and a second end of the third conductor 51 or the third Line constriction 53 can be connected in an electrically conductive manner to the load-side converter 20 via a (second) conductor piece 32b of the second circuit branch 32 .

In order to establish the connection to the input of the line-side converter 10, the fourth

Conductor 52 or the fourth line constriction 55 of the second short-circuiting device 50 (e.g. via a

Conductor piece 56) with the second mains connection 12 of the mains-side converter 10 be electrically conductively connected tend. Advantageously, in the event of a fault, the current can be shifted or the short-circuit current diverted to the second mains connection 12 of the mains-side converter 10 . By the exemplary provision of two short-circuiting devices 40 and 50 in the DC voltage link 30, depending on the error, reliable protection of the

Inverter 100 can be achieved. For example, in the event of an overload in the DC voltage

Intermediate circuit 30 (indicated by arrow 81), both short-circuiting devices 40 and 50 respond, whereas in the event of a fault to ground (indicated by arrows 82 and 83), only one of the two short-circuiting devices, i. H. e.g. B. only the first short-circuiting device 40 or only the second short-circuiting device 50 can respond.

FIG. 3 shows a schematic representation of a converter 100 according to a third embodiment. This embodiment also has two short-circuiting devices 40 and 50 in an example

DC link 30 on. As already mentioned above in connection with FIG

has been described in detail, according to this exemplary variant, the first conductor 41 of the first short-circuiting device 40 can in turn be in the first circuit branch 31 of the DC voltage

Intermediate circuit 30 may be arranged and the third conductor 51 of the second short-circuiting device 50 may in turn be arranged in the second circuit branch 51 of the DC voltage intermediate circuit 30 . In comparison to the variant according to FIG. 2, however, the second conductor 52 of the first short-circuiting device 40 and the fourth conductor 52 of the second short-circuiting device 50 LU500997 are not connected to the input of the line-side converter 10 in the present case.

According to the present exemplary variant, the second conductor 42 of the first short-circuiting device is electrically conductively connected to the fourth conductor of the second short-circuiting device 50 via a preferably potential-free connecting line 60 . For example, a first (distal) end of the connecting line 60 can be connected to the second conductor 42 or the second line constriction 43 of the first short-circuiting device 40 and/or a second (distal)

The end of the connecting line 60 can be connected to the fourth conductor 52 or the fourth line constriction 43 of the second short-circuiting device 50 . Advantageously, this allows a

Merging of the two short-circuiting devices 40 and 50 are made possible in order to separate subsequent components from the current flow in the event of a fault.

Figure 4 shows a schematic detailed representation of a short-circuiting device according to a

embodiment. The corresponding components are described with reference to the nomenclature of the first short-circuiting device 40 merely as an example. However, it is immediately obvious to a person skilled in the art that the second short-circuiting device 50 can also be designed accordingly. The first short-circuiting device 40 shown as an example has a first conductor 41 (eg in the form of a conductor track) and a second conductor 42 (eg in the form of a conductor track). The second conductor 42 is in this case from the first conductor 41, z. B. electrically isolated by an insulating circuit board material not shown in detail. Furthermore, the first conductor 41 has a line constriction, which should be referred to as the first line constriction 43 for better differentiation. The first line constriction 43 is preferably a (local) narrowing of the conductor cross section. i.e. the first conductor 41 can in the first line constriction 43 z. B. thinner than before and / or after the first line constriction 43 may be formed. For example only, the first constriction 43 z. B. be zigzag-shaped, i. H. the first conductor 41 can there run in a zigzag line with corresponding conductor tips.

The second conductor 42 can also, as shown by way of example, have a line constriction, which should be referred to as the second line constriction 45 for better differentiation. For example, the second line constriction 45, as shown, can be in an end area of the second conductor 42 be arranged. The second line constriction 45 of the second conductor 42 is preferably also designed in a zigzag shape. Furthermore, the second line constriction 45 of the second

Conductor 42 may be arranged adjacent to the first line constriction 43 of the first conductor 41. At-

For example, the first and second line bottlenecks 43, 45 can be arranged offset plane-parallel, preferably at a small distance from one another. The first and second line constriction 43, 45 can thus only be separated from one another by a preferably thin insulating layer 44 (not expressly shown). This geometry of the first short-circuiting device 40 can advantageously provide a (defined) target breakdown point which, in the event of a fault, enables a corresponding formation of a conductive connection between the first and second conductors 41, 42 by destroying the insulation layer 44 induced by a short-circuit current.

FIG. 5 shows a schematic sectional illustration of a short-circuiting device embedded in a printed circuit board 70 according to an embodiment. For the highest possible operating safety in the claimed converter 100, all lines of the converter 100 are preferably provided

Lead mains input to the load output in an inner layer of a printed circuit board 70. FIG. 5 shows a corresponding sectional view in the area of the first short-circuiting device 40 in this regard

DC link 30. In the middle of the circuit board, which z. B. can consist of ceramic materials, plastics such as polyamide or polytetrafluoroethylene, and/or other materials, the first short-circuiting device 40 is arranged here by way of example. A section through the first and second line bottlenecks 43, 45, which are separated from one another by an insulating layer 44, is shown. The distance between the first line constriction 43 and the second line constriction 45 or the thickness of the separating insulation layer 44 can, as shown here, be less than the lateral extension of the respective first or second conductor 41, 42 in the region of the respective line constriction 43, 45 be. Furthermore, the printed circuit board 70 can include further line layers, with the line layers 71, 72, 73 and 74 being shown here merely as examples. By appropriately arranging the one or more

Short-circuiting devices within the printed circuit board 70 has the advantage that the energy released in the event of a short circuit is as far as possible within the printed circuit board and therefore not on others

surface is released.

FIG. 6 shows an exemplary current curve over time in the event of a short circuit in a claimed converter 100 with a first short-circuiting device 40 according to one embodiment. First of all, the short-circuit current in the DC voltage intermediate circuit 30 of the converter 100 (curve 5a) rises more or less linearly. After an interval Δt then the first short-circuiting device 40 of the converter responds, i. H. the insulating layer 44 of the first short-circuiting device 40 is destroyed and the first short-circuiting device 40 becomes electrically conductive (e.g. by sparking or arcing) or there is then an electrically conductive connection between the first and second conductors 41, 42 . Accordingly, the short-circuit current in the DC voltage intermediate circuit 30 collapses and a current shift via the first short-circuiting device 40 takes place. The current then flowing via the first short-circuiting device 40 is shown in curve 5b. This continues to increase until finally the current flow preferably stops as a result of a switching of a current-limiting switching element 3 (e.g. a

circuit breaker and/or a fuse) is terminated. The time interval At until the first short-circuiting device 40 is triggered can be achieved by appropriately designing the first line constriction 43 or via the material of the insulating layer 44 and/or via the

The expansion, in particular the thickness, of the insulation layer 44 can be adjusted, which can be determined, for example, by means of appropriate preliminary tests.

Although the invention has been described with reference to specific exemplary embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents substituted without departing from the scope of the invention. Accordingly, the invention should not be limited to the disclosed embodiments, but should include all embodiments falling within the scope of the appended claims. In particular, the invention also claims protection for the subject matter and the features of the subclaims independently of the claims referred to.

LIST OF REFERENCE NUMBERS LU500997 1 load 2 power supply network 3 circuit breaker

4 PE conductor 5a current curve before ignition of the short-circuiting device 5b current curve after ignition of the short-circuiting device line-side power converter

10 11 first grid connection 12 second grid connection 13 third grid connection 20 load-side power converter 21, 22, 23 connections

30 DC voltage intermediate circuit 31 first circuit branch 31a first conductor section 31b second conductor section 32 second circuit branch

32a first conductor section 32b second conductor section 33 intermediate circuit capacitor 40 first short-circuiting device 41 first conductor

42 second conductor 43 first line constriction 44 insulating layer 45 second line constriction 46 conductor section

50 second short-circuiting device 51 third conductor 52 fourth conductor 53 third line constriction 54 further insulation layer fourth insulation layer

56 conductor piece LU500997 70 printed circuit board 71,72, 73, 74 cable layers 81 overload in the DC link circuit 82, 83 fault to earth 100 converter 101 housing ca

Claims (17)

EXPECTATIONS 1. Converter (100) for connecting an electrical load (1), preferably an electric motor, to an energy supply network (2), having a line-side converter (10) and a load-side converter (20), the line-side converter (10) and the load-side power converter (20) are electrically conductively connected to one another via a DC link (30); characterized in that the DC voltage intermediate circuit (30) has at least one short-circuiting device (40, 50), the at least one short-circuiting device (40, 50) being designed to automatically produce at least one electrically conductive connection as a result of a short-circuit current in the DC voltage intermediate circuit (30). to divert the short-circuit current. 2. The converter (100) according to claim 1, characterized in that the at least one short-circuiting device (40, 50) comprises a first short-circuiting device (40), the first short-circuiting device (40) having a first conductor (41) and a, from first conductor (41) comprises electrically insulated second conductor (42); the first conductor (41) having a first constriction (43); and wherein the first line constriction (43) is designed in such a way and the second conductor (42) is guided past the first line constriction (43) of the first conductor (41) in such a way that between the first line constriction (43) and the second conductor (42 ) Existing insulating layer (44) is destroyed in the event of a short-circuit current via the first conductor (41), so that the at least one electrically conductive connection between the first conductor (41) and the second conductor (42) is present. 3. The converter (100) as claimed in claim 2, characterized in that the first and second conductors (41, 42) a) are arranged at least in sections in a wavy, zigzag shape and/or, preferably with sharp edges, in a meandering shape; and/or b) are arranged parallel to one another at least in sections; and/or c) have at least one, preferably several, changes in direction. 4. Converter (100) according to claim 2 or 3, characterized in that the insulating layer (44) can be heated by a current flow through the first line constriction (43), and that the Insulation layer (44) is designed to melt and/or evaporate when a predetermined temperature is reached. 5. Converter (100) according to one of Claims 2 to 4, characterized in that the second conductor (42), preferably an end region of the second conductor (42), has a second line constriction (45), the second line constriction (45) of the second conductor (42) is arranged adjacent to the first line constriction (43) of the first conductor (41). 6. Converter (100) according to one of Claims 2 to 5, characterized in that the DC link (30) has a first circuit branch (31) which connects the line-side converter (10) and the load-side converter (20 ) connects to each other, and that the first conductor (41) of the first short-circuiting device (40) is arranged in the first circuit branch (31) or in front of the first circuit branch (31), 7. Converter (100) according to one of Claims 2 to 6, characterized in that the DC link (30) has a second circuit branch (32) which connects the line-side converter (10) and the load-side converter (20 ) connects to each other, and that the second conductor (42) of the first short-circuiting device (40) is arranged in the second circuit branch (32) or in front of the second circuit branch (32), 8. Converter (100) according to any one of claims 2 to 7, characterized in that the mains-side power converter (10) has a first mains connection (11) for connecting to the energy supply network (2), and that the second conductor ( 42) of the first short-circuiting device (40) is connected to the first mains connection (11) of the mains-side converter (10). 9. Converter (100) according to one of the preceding claims, characterized in that the DC link (30) comprises a second short-circuiting device (50), the second short-circuiting device (50) having a third conductor (51) and one, electrically connected to the third conductor (51) comprises an insulated second conductor (52); the third conductor (51) having a third constriction (53); and wherein the third line constriction (53) is designed in such a way and the fourth conductor (52) is guided past the third line constriction (53) of the third conductor (51) in such a way that between the third line constriction (53) and the fourth conductor (52 ) existing further insulation layer (54) is destroyed in a short-circuit current via the third conductor (51), so that the at least one electrically conductive connection between the third conductor (51) and the fourth conductor (52) is present. 10. Converter (100) according to Claim 9, characterized in that the DC voltage intermediate circuit (30) has a second circuit branch (32) which connects the line-side converter (10) and the load-side converter (20) to one another, and that the third conductor (51) of the second short-circuiting device (50) is arranged in the second circuit branch (52). 11. Converter (100) according to claim 9 or 10, characterized in that the line-side converter (10) has a second line connection (12) for connecting to the energy supply network (2), and that the fourth conductor (52) of the second Short-circuiting device (50) is connected to the second mains connection (12) of the mains-side converter (10). 12. Converter (100) according to any one of claims 9 to 11, characterized in that the fourth conductor (52) of the second short-circuiting device (50) via a, preferably potential-free, connecting line (60) to the second conductor (42). first short-circuiting device (40) is connected. 13. The converter (100) according to any one of claims 9 to 12, characterized in that a) the third and fourth conductors (51, 52) are arranged at least in sections a1) at least in sections in a wavy, zigzag shape, preferably with sharp edges, in a meandering shape ; and/or a2) are arranged parallel to one another at least in sections; and/or a3) have at least one, preferably several, changes of direction; and/or b) that the further insulation layer (54) can be heated by a current flow through the third line constriction (53), and that the further insulation layer (54) is designed to melt and/or to ver - steam; and/or c) that the fourth conductor (52), preferably an end region of the fourth conductor (52), has a fourth line constriction (55), the fourth line constriction (55) of the fourth conductor (52) adjoining the third line constriction (53) of the third conductor (51) is arranged. 14. Converter (100) according to one of claims 2 to 13, characterized in that the first and/or the second short-circuiting device (40, 50) is arranged within a printed circuit board (70) and/or between two printed circuit boards fastened to one another. 15. Converter (100) according to one of the preceding claims, characterized in that the line-side converter (10) is a three-phase converter and/or that the load-side converter (20) is a three-phase converter. 16. Converter (100) according to one of the preceding claims, characterized in that the DC voltage intermediate circuit (30) has an intermediate circuit capacitor (33), the first and second circuit branches (31, 32) preferably being electrically coupled via the intermediate circuit capacitor (33). are. 17. Use of a converter (100) according to any one of the preceding claims, for connecting an electrical load (1), preferably an electric motor, to a power supply network (2), having an automatic formation of at least one electrically conductive connection by means of the at least one short-circuiting device (40, 50) of the converter (100) by a short-circuit current in the DC link (30). * KK x kx