WO2023110286A1

WO2023110286A1 - Short-circuit protection for a converter

Info

Publication number: WO2023110286A1
Application number: PCT/EP2022/082448
Authority: WO
Inventors: Elmar Schaper; Alexander GÜNTER
Original assignee: Phoenix Contact Gmbh & Co. Kg
Priority date: 2021-12-13
Filing date: 2022-11-18
Publication date: 2023-06-22
Also published as: LU500997B1

Abstract

The invention relates, inter alia, to a converter (100) for connecting an electrical load (1) to a power supply grid (2), comprising a grid-side power converter (10) and a load-side power converter (20), wherein the grid-side power converter (10) and the load-side power converter (20) are electrically interconnected by means of DC link (30). The invention is characterized in that the DC link (30) has at least one short-circuit device (40, 50), the at least one short-circuit device (40, 50) being designed such that, as a result of a short-circuit current in the DC link (30), the at least one short-circuit device automatically forms at least one electrical connection for redirecting the short-circuit current. The invention also relates to the use of a converter (100) of this type to connect an electrical load (1) to a power supply grid (2).

Description

Short-circuit protection for a converter

The invention relates to a converter for connecting an electrical load to an energy 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 an energy supply network.

For reasons of electrical safety, protection against short circuits is usually required for mains applications. Usually this current-limiting switching elements such. As 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 required to switch off). The requirements for the corresponding variables depend on the connection values of the supply network, the switching element, the connected impedance that is effective despite the short-circuit (network impedance, line impedance, etc.) and the other elements that have to carry the short-circuit current.

A frequent problem when using the aforementioned current-limiting switching elements is that the permissible parameters for a downstream switching element (e.g. contactor, motor switching device, etc.) could be exceeded and smaller fuses therefore have to 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 switch off high short-circuit currents only too slowly, so that currents that are too high may flow through the downstream elements, which can lead to damage there.

Last but not least, this problem is relevant for frequency converters, especially since the requirements for short-circuit resistance have increased there. With frequency converters, there is 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 errors in the intermediate circuit with 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. It is therefore the object of the invention to provide such a solution, in which case the disadvantages of previous approaches should preferably also be avoided. In particular, it is an object of the invention to provide fast and safe short-circuit protection in the converter, by means of which the release of energy to the outside can be avoided as far 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 preferably feedback-capable converter has a first converter, which can also be referred to below as a line-side converter for better differentiation. 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 line-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 power converter can be used for connection to the load and/or can include one or more inputs for connection to the load. The load-side power converter 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 designed as 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 grid-side term power converter to a positive DC voltage-side connection of the load-side power converter, while the second branch circuit (DC) connects a negative DC voltage-side connection of the line-side power converter to a negative DC voltage-side connection of the load-side power converter. The DC voltage intermediate circuit preferably also has one or more intermediate circuit capacitors for smoothing the voltage in the intermediate circuit. 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 to divert and/or re-channel the Short-circuit current is used. Preferably, the at least short-circuiting device is thus designed to provide an additional current path for the short-circuit current (e.g. to derive it from the converter into the power supply network) if there is a short-circuit current in the DC link, 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) target 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 from the intermediate circuit and routed to a suitable point (e.g. back into the power supply network).

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 (e.g. 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 this way and the second conductor can also be designed in this way at the first line constriction be routed past the first conductor so that an insulation layer (e.g. a plastic such as polyurethane and/or a glass-fibre reinforced plastic such as FR4) between the first line constriction and the second conductor is destroyed, preferably thermally, in the event of a short-circuit current via the first conductor, so that the aforementioned at least one electrically conductive connection is present 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. In other words, deliberate (local) damage to the circuit to form an additional current path should preferably take place here, which is why the first short-circuiting device can also be referred to as the first desired breakdown point. Advantageously, this can automatically (in the event of a short circuit) shift the current via the newly formed or specifically created electrically conductive connection in such a way that the second conductor takes over the fault current from the intermediate circuit and sends it to a suitable location (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 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 region 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 be at the same distance at the first short-circuiting device or at the first line constriction run side by side. 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 course, the corresponding courses such (z. B. plane-parallel) are shifted or offset from one another that the first and second conductors in this area are always at a fixed distance run towards each other. In an alternative embodiment, the second conductor can also be T-shaped in its end region, in which case the crossbar of the T-shape can be arranged to run 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. By way of example only, the first and second conductors may 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, in particular in the event of a short circuit. In addition or as an alternative, the insulating layer (e.g. a plastic) can also be designed to melt and/or evaporate when a predetermined temperature is reached. Preferably, a time interval can 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 (e.g. due to flashover or arcing) becomes electrically conductive. 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 found by a person skilled in the art, e.g. B. by appropriate preliminary tests (short-circuit tests). Overall, this allows advantageously the breakdown properties of the short-circuiting device can be set or specified.

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 be understood as a narrowing or tapering of the respective conductor cross-section, i.e. a deliberate (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 bottlenecks can thus be arranged, preferably close together, and/or in the immediate vicinity. The first and second line bottlenecks are therefore preferably only separated from one another by the aforementioned insulation layer advantageously the crosstalk or formation of a conductive connection between the first and second conductors can be set.

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. By way of example only, 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+). Alternatively, the first circuit branch can also connect a negative DC voltage-side connection of the line-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) can 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. B. via another conductor piece of the first circuit branch) with the load-side power converter be electrically connected. Advantageously, when the DC voltage intermediate circuit is overloaded, a current shift from the intermediate circuit can be made possible by a response of the first short-circuiting device.

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 direct 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. B. connect the first circuit branch a positive DC voltage side terminal of the line-side converter with a positive DC voltage side terminal of the load-side converter, while z. B. the second circuit branch (z. B. in the form of a conductor track or conductor rail) can connect a negative DC voltage-side terminal of the line-side converter with a negative DC voltage-side terminal 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) can be electrically conductively connected to the line-side converter and/or a second end of the second conductor or the second line constriction (e.g. B. via another conductor piece of the second circuit branch) with the load-side power converter can be electrically conductively connected. The first conductor and the second conductor are therefore preferably located in different circuit branches of the DC voltage intermediate circuit, i. H. e.g. B. the first conductor in the first circuit branch and the second conductor in the second circuit branch. Advantageously, in the event of a fault, a targeted connection between the circuit branches of the DC voltage intermediate circuit can be made possible in order to separate subsequent components from the current flow.

According to a further aspect, the grid-side power converter can have a first grid connection for connecting to the power supply grid. The first mains connection, which can also be referred to as the first mains-side input of the mains-side converter, z. B. for connecting to a (first) phase (z. B. LI) be formed of a three-phase power supply network. For this purpose, the first 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 power supply network. Furthermore, the second conductor of the first short-circuiting device be connected (electrically conductive) to the aforementioned first network connection of the network-side power 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). Advantageously, this can result in a current shift or derivation of the short-circuit current 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 further increase the short-circuit protection of the converter in an advantageous manner, according to a further aspect, the DC voltage intermediate circuit can have 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 constructed identically to the first short-circuiting device, with the corresponding components being referenced differently in the following for better differentiation. Thus, the second short-circuiting device can in particular comprise a third conductor and a fourth conductor, it being possible for the fourth conductor to be electrically insulated from the third conductor (e.g. by an insulating circuit board material). Furthermore, the third conductor can have a line constriction (e.g. in the form of a sectional narrowing of the first conductor), which can be referred to as a "third" line constriction to distinguish it from the aforementioned "first" or "second" line constrictions of the first short-circuiting device. 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 overshoot in the event of a short-circuit current the third conductor is destroyed, preferably thermally, so that the aforementioned at least one electrically conductive connection is present between the third conductor and the fourth conductor.Analogously to the first short-circuiting device, the second short-circuiting device can also be preferably designed such that 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 adjoining further insulating layer can be destructible as a result of this local (high) excess temperature in the area of the line constriction, with the formation of a plasma channel, so that crosstalk to the adjoining fourth conductor is made possible. Advantageously, in addition to or as an alternative to triggering the first short-circuiting device, a (further) current transfer via the newly formed or specifically created current path of the second short-circuiting device can thereby be made possible. According to a further development of this aspect, the third conductor of the second short-circuiting device--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 link. As has already been explained above, the second circuit branch can connect the line-side converter and the load-side converter to one another (electrically conductive). For example, the second circuit branch (z. B. in the form of a conductor track or conductor rail) connect a negative DC voltage side terminal of the line-side power converter with a negative DC voltage side terminal of the load-side converter, while z. B. the first circuit branch can connect a positive DC voltage-side terminal of the line-side converter to a positive DC voltage-side terminal 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 converter (e.g. via a conductor section of the second circuit branch) and/or a second end of the third conductor or the third line constriction (e.g. B. via another conductor piece of the second circuit branch) with the load-side power converter can be electrically conductively connected.

According to a further aspect, the grid-side power converter can have a second grid connection for connecting to the power supply grid. 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 power 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 (e.g. 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 thereby take place, as a result of which 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, 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 manner, preferably in a sharp-edged meandering manner, analogously to the embodiment variants of the first short-circuiting device. Preferably, the third line constriction of the third conductor and/or an end region of the fourth conductor can be arranged at least in sections in a wavy and/or zigzag shape and/or (sharp-edged) meander shape. This type of embodiment 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 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 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 next to one another at the same distance in the case of the second short-circuiting device or in the case of 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. Merely by way of example, the fourth conductor can be configured in a T-shape in its end region, it being possible for the transverse line of the T-shape to be arranged running parallel to the third conductor or the third line constriction. In this way, an extended desired breakdown point can be provided in an advantageous manner.

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 preferably change their course or direction course one or more times in the case of the second short-circuiting device or in the case of the third line constriction. 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 conductor z. B. be arranged in a meandering shape, with others 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.

Additionally or alternatively, the further insulation layer (present between the third line constriction and the fourth conductor) can be heatable by a current flow through the third line constriction. i.e. the further insulation layer can thus be thermally coupled to the third conductor or the third line constriction in order, in particular in the event of a short circuit, to absorb heat from the third line constriction. 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, a time interval can be set via the material of the further insulation layer and/or via the extent, in particular thickness, of the further insulation layer 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. B. by sparking or arcing) becomes electrically conductive. With regard to the time interval or the breakdown properties, the second short-circuiting device can be configured 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 arranged in an end region (eg at a distal end) of the fourth conductor. 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 Closing device can also be arranged between two printed circuit boards attached to one another. Provision is preferably made for all the cables of the converter to be routed in an inner layer of a printed circuit board. The corresponding arrangement of the conductors and in particular the first and/or second 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 other surfaces. A plasma cloud on the surface of the circuit board, which z. B. with regard to protection against accidental contact and components flying around as a result of a pressure surge, can thus be effectively avoided.

According to a further aspect, the grid-side converter can be a three-phase converter. The line-side power converter can thus have at least three line connections on the line 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 connections on the load side. The load terminals can serve and/or be designed to connect one phase of a three-phase load (e.g. each 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, a use of a converter as described in this document for connecting an electrical load (e.g. an electric motor) to a power supply network is provided. The features described in connection with the converter should also be considered disclosed and claimable in connection 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 current or mediated by the short-circuit current, a preferably automatic formation of a new or additional current path can take place, with this preferably serving to divert the short-circuit current.

In the event that the at least one short-circuiting device comprises 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 an electrically conductive connection between between the first and second conductors. In this case, the insulation layer present between the first line constriction and the second conductor can preferably be heatable by a current flow through the first line constriction, in which case the insulation layer (e.g. a plastic) can be designed to melt and/or close when a predetermined temperature is reached evaporate. In other words, in the case of a short-circuit current, the use can include deliberately inducing 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 conductors (e.g. B. by arcing, or arcing) are electrically connected. If the converter also includes an aforementioned second short-circuiting 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 an electrically there is a 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 shows 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 an 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 specific embodiment. The generic converter 100 is preferably a frequency converter, i. H. a device for converting a fed-in AC voltage into another AC voltage (e.g. with a changed frequency and/or amplitude). The converter 100, the z. 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 can be a three-phase power supply network in the present case - merely by way of example . The preferably regenerative converter 100 has a line-side converter 10 . The line-side converter 10 can be used for connection to the power supply system 2 and can accordingly comprise 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 converter 20. The load-side converter 20 can be used to connect to the load 1 and accordingly include one or more connections, in this case three connections 21, 22 and 23, for connection to the load 2. For example, the load-side power converter 20 can be embodied as a preferably self-commutated inverter (eg an IGBT inverter), which is embodied 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 line-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. The DC voltage intermediate circuit 30 preferably also has an intermediate circuit capacitor 33 for smoothing the voltage in the DC voltage intermediate circuit 30 . In this case, 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. may include intermediate circuit capacitors 33 connected in parallel and/or 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 provide fast and safe short-circuit protection in the converter 100 or in the DC link 30 in an advantageous manner, the DC link 30 also has at least one short-circuiting device, with the present exemplary embodiment only comprising a (first) short-circuiting device 40. 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 faults: an internal short circuit (e.g. a diode) in the line-side 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 33, a general insulation fault in the DC voltage intermediate circuit 30 and/or an insulation fault in the DC voltage intermediate circuit 30 due to external influences (e.g. due to moisture, dust or metal shavings). The at least one short-circuiting device is designed to automatically form at least one (additional) electrically conductive connection as a result of a short-circuit current in the DC voltage intermediate circuit 30 (e.g. as a result of one of the aforementioned cases), the at least one electrically conductive connection preferably being used for rerouting and/or or re-channelling the short-circuit current.

As shown here, the at least one short-circuiting device can include a first short-circuiting device 40 for this purpose, the exemplary structure of which will be described in more detail in connection with FIG. The first short-circuiting device 40 may 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 printed circuit board material). Furthermore, the first conductor 41 can have a first line constriction 43 (e.g. 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 the first conductor 41 runs there in a zigzag line with several changes in 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 (e.g. a plastic such as polyurethane) is destroyed, preferably thermally, in the event of a short-circuit current via the first conductor 41, so that the aforementioned at least one electrically conductive connection between the first conductor 41 and the second conductor 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 device 40 can also be referred to as a desired breakdown point. For this purpose, the second conductor 42 preferably also has a line constriction 45 (e.g. also zigzag-shaped), which should be referred to as the “second” line constriction 45 for better differentiation End region of the second conductor 42 can be arranged and/or arranged adjacent to the first line constriction 43 of the first conductor 41. The first and second line constriction 43, 45 can thus preferably be arranged close together and/or in the immediate vicinity and only by preferably thin, insulating layer 44. As already described above, this can advantageously automatically allow a current shift via the second conductor 42, which is then connected to the first conductor 41, in the event of a short circuit, such that this second conductor 42 can carry the fault current takes over from the DC voltage intermediate circuit 30 and derives it at a suitable point, which will be described in more detail below. Since the formation of the additional current path only takes a few milliseconds (see Figure 6) and is therefore significantly faster than a circuit breaker that is preferably additionally present (typically 10-20 ms), quick and reliable short-circuit protection for the Converter 100 are 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 embodied 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 electrically conductively connected to the line-side converter 10 via a (first) conductor section 31a of the first circuit branch 31, and a second end of the first conductor 41 or the first line constriction 43 be electrically conductively connected to the load-side converter 20 via a (second) conductor piece 31b of the first circuit branch 31 . 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, a first end of the second conductor 42 or the second line constriction 45 can be electrically conductively connected to the line-side converter 10 via a (first) conductor section 32a of the second circuit branch 32 and a second end of the second conductor 42 or the second line constriction 45 be electrically conductively connected to the load-side converter 20 via a (second) conductor piece 32b of the second circuit branch 32 . In the event of a fault, a targeted connection between the circuit branches 31 and 32 of the DC voltage intermediate circuit 30 can thereby be made possible in an advantageous manner, in order thereby 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 arranged in the first circuit branch 31 of the DC voltage intermediate circuit 30 . 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 converter 10 and by means of a second conductor piece 31b of the first circuit branch 31 with the load-side converter 20 electrically be conductively connected. The second conductor 42 or the second line constriction 45 of the first short-circuiting device 40 is in the present example electrically conductively connected (via a conductor piece 46) to the first grid connection 11 of the grid-side converter 10. Advantageously, in the event of a fault, the current can be shifted or the short-circuit current diverted to the input of the line-side converter 10, so that the energy can be routed past the line-side converter 10, in particular any diodes that may be present there.

In addition to the first short-circuiting device 40 described above, the DC link 30 in the exemplary embodiment shown has a further (second) short-circuiting device 50 . The basic structure of this second short-circuiting device 50 can be identical to that of the first short-circuiting device 40 (as shown by way of example), although the corresponding components are referenced differently 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 (e.g. by an insulating circuit board material). Furthermore, the third conductor 51 can have a "third" line constriction 53 (e.g. in the form of a sectional narrowing of the first conductor). In the present case, the third line constriction 53 is again - merely by way of example - zigzag-shaped. 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 a further insulation layer 54 (e.g. a plastic such as polyurethane) present between the third line constriction 53 and the fourth conductor 52 a short-circuit current via the third conductor 51, preferably thermally, is destroyed, so that there is an electrically conductive connection between the third conductor 51 and the fourth conductor 52.

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 is 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 further insulating layer 54, which is preferably thin. As has already been described above for the first short-circuiting device 40, the second short-circuiting device 50 can thus also be advantageous In the event of a short circuit, another current path for dissipating the short-circuit current 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 section 32a of the second circuit branch 32, and a second end of the third conductor 51 or the third line constriction 53 be electrically conductively connected 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) can be electrically conductively connected to the second line connection 12 of the line-side converter 10. Advantageously, in the event of a fault, the short-circuit current can be shifted or diverted to the second grid connection 12 of the grid-side converter 10 . By providing, for example, two short-circuiting devices 40 and 50 in the DC voltage link 30, reliable protection of the converter 100 can be achieved depending on the fault. For example, in the event of an overload in the DC link 30 (indicated by arrow 81), both short-circuiting devices 40 and 50 would 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 specific embodiment. This embodiment also has two short-circuiting devices 40 and 50 in the DC link 30 as an example. As has already been described in detail above in connection with Figure 2, according to this exemplary variant, the first conductor 41 of the first short-circuiting device 40 can again be arranged in the first circuit branch 31 of the DC voltage intermediate circuit 30 and the third conductor 51 of the second short-circuiting device 50 can again be arranged in the second circuit branch 51 of the DC link 30 may be arranged. In comparison to the variant shown in Figure 2, however, the second conductor 52 are present first short-circuiting device 40 and the fourth conductor 52 of the second short-circuiting device 50 is not connected to the input of the line-side converter 10 .

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) 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 may be connected. Advantageously, this allows the two short-circuiting devices 40 and 50 to be brought together in order to separate subsequent components from the current flow in the event of a fault.

FIG. 4 shows a schematic detailed representation of a short-circuiting device according to an 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. 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. zigzag-shaped, d. 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 can be arranged in an end region of the second conductor 42, as shown. 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 can 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, it is preferably provided that all lines of the converter 100 are routed from the mains input to the load output in an inner layer of a printed circuit board 70. For this purpose, FIG. B. from ceramic materials, plastics such as polyamide or polytetrafluoroethylene, and / or other materials, the present example, the first short-circuiting device 40 is arranged. 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 insulating 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 . Furthermore, the printed circuit board 70 can include further line layers, the line layers 71, 72, 73 and 74 being shown here merely as examples. 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 released as far as possible within the printed circuit board and thus not on other surfaces.

FIG. 6 shows an exemplary current profile over time in the event of a short circuit in a claimed converter 100 with a first short-circuiting device 40 according to one specific embodiment. First of all, the short-circuit current in the DC link 30 of the converter 100 (curve 5a) rises more or less linearly. After an interval At, the first short-circuiting device 40 of the converter then responds, ie 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 sparkover or arcing) or an electrically conductive one is then present connection between the first and second conductors 41, 42. Accordingly, the short-circuit current in the DC link 30 collapses and a current shift takes place via the first short-circuiting device 40 . 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 is preferably ended by switching a current-limiting switching element 3 (eg a power circuit breaker and/or a safety fuse) upstream of the converter 100 on the network side. The time interval At until the first short-circuiting device 40 is triggered can be set by appropriately designing the first line constriction 43 or via the material of the insulation layer 44 and/or via the extent, in particular thickness, of the insulation layer 44, which is determined, for example, by means of corresponding preliminary tests can be.

Although the invention has been described with reference to specific 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.

Reference List

1 load

2 power supply network

3 circuit breakers

4 PE conductors

5a Current curve before ignition of the short-circuiting device

5b Current curve after ignition of the short-circuiting device

10 line-side power converters

11 first power connection

12 second power connector

13 third power connector

20 load-side power converters

21, 22, 23 connections

30 DC link circuit

31 first circuit branch

31a first conductor section

31b second conductor piece

32 second circuit branch

32a first conductor section

32b second conductor piece

33 intermediate circuit capacitor

40 first short-circuiting device

41 first ladder

42 second conductor

43 first line bottleneck

44 insulation layer

45 second line constriction

46 piece of ladder

50 second short-circuiting device

51 third conductor

52 fourth conductor

53 third line constriction

54 more insulation layer

55 fourth insulating layer 56 piece of ladder

70 circuit board

71, 72, 73, 74 cable layers

81 DC link overload 82, 83 Earth fault

100 converters

101 housing

* * * *

Claims

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 converters (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 one from the first conductor (41) 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. Converter (100) according to 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. . 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 Insulating 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) to one another, 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). . 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) to one another, 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). . Converter (100) according to one of Claims 2 to 7, characterized in that the line-side converter (10) has a first line connection (11) for connection to the energy supply network (2), and in 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 link (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 power converter (10) has a second line connection (12) for connection to the power supply system (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 one of Claims 9 to 11, characterized in that the fourth conductor (52) of the second short-circuiting device (50) is connected to the second conductor (42) of the first short-circuiting device via a preferably potential-free connecting line (60). (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 evaporate when a predetermined temperature is reached; 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 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).