BE1031299B1 - DC switching device, in particular for interrupting a current flow, and DC system - Google Patents

Abstract

The invention relates, among other things, to a DC voltage switching device (10) with a first, second, third and fourth device connection (11-14), a first current path (1) and a second current path (2) and a single electrical fuse (20). An anti-serial circuit (60) which has a first controllable semiconductor switch (61) and a second controllable semiconductor switch (62) is arranged in one of the two current paths (1, 2), while the fuse (20) is arranged in the other current path (1, 2). Furthermore, a first and second controllable short-circuit switch (50, 51) and a current detection device (30) are provided. A control and evaluation device (40) is designed to switch on the first or second short-circuit switch (50, 51) depending on the direction and current intensity detected by the current detection device (30), provided that the detected current intensity reaches or exceeds a predetermined threshold value, which diverts a short-circuit current via the fuse (20).

Description

DC switching device, in particular for interrupting a current flow, and DC system

Description

The invention relates to a DC switching device, which in particular allows an electric current flow between the input side and the output side of the

DC switching device or between two DC devices. The invention further relates to a DC system which has such a DC device.

For example, in order to electrically connect or disconnect a DC load from a DC voltage source, a

DC switching device. The input terminals of the

DC switching device, an external DC voltage source, e.g. a DC

supply network or a DC bus, while the

Output terminals of the DC switching device, a DC load can be connected. The DC switching device comprises at least one switching element for electrically switching the DC load on and off. A controllable semiconductor switching element is often used for this purpose, which is located in the circuit between the first

input terminal and the first output terminal or in the negative conductor running between the second input terminal and the second output terminal. Furthermore, an electromechanical switch can be provided. If the semiconductor switching element is switched to conductive, a current flows between the DC voltage source and the

DC load. This current flow can be stopped by switching off or opening the

Semiconductor switching element, however, can be prevented or interrupted.

In particular, special measures must be taken to protect the DC device and/or an electrical load connected to it from damage or destruction as a result of a short circuit.

For example, an electronic switch for isolating a current flow is known from EP 3 891 890 B1. A regenerative power supply can be connected to the electronic switch.

load can be connected to a second and fourth terminal, while a

Energy source can be connected to a first and third terminal. Furthermore, the electronic switch has two anti-serially connected semiconductor switches to enable current to flow in both directions through the electronic switch. Two fuses are connected in series with the two semiconductor switches, with the two semiconductor switches being arranged between the two fuses. The two fuses serve to protect the load, the energy source or the switching device itself if a short-circuit current occurs. In particular, to protect the two anti-serially connected semiconductor switches from a

To protect against short-circuit current, two short-circuiters, which can be designed as thyristors, are connected to the fuses in such a way that a series connection of a fuse and a short-circuiter is arranged between the first and third

connection and between the second and fourth connections.

The present invention is based on the object of

DC switching device, in particular for interrupting a current flow, and a DC voltage system which, with a reliable

Short-circuit resistance can be constructed with fewer components and thus more cost-effectively than the known electronic switch.

A core idea of the invention can be seen in the

To provide a DC switching device that can be operated with a single

fuse, even if the DC switching device is connected to both

current directions.

The above-mentioned technical problem is solved with the features of claim 1.

Accordingly, a DC switching device, in particular for interrupting a

current flow, which can have the following features: - a first and a second device connection, - a first current path which is electrically connected to the first and second device connection, - a third and a fourth device connection, - a second current path which is electrically connected to the third and fourth device connection, - a single electrical fuse, - an anti-serial circuit which has a first controllable semiconductor switch and a second controllable semiconductor switch (62) which is anti-serial to the first

Semiconductor switch, wherein a first diode is connected antiparallel to the first semiconductor switch and a second diode is connected antiparallel to the second

Semiconductor switches are connected, wherein the electrical fuse is arranged in the second current path and the first and second

Semiconductor switches are arranged in the first current path, - a current detection device which is designed to determine the direction and

current intensity of a current flowing through the first or second current path, - a first controllable short-circuit switch having a first terminal and a second terminal, the first terminal being electrically connected to the first

current path and between the second device connection and the anti-serial

circuit, and the second terminal is electrically connected to the second

current path and between the third device connection and the electrical

fuse is arranged, - a second controllable short-circuit switch having a first terminal and a second terminal, wherein the first terminal is electrically connected to the first

current path and between the first device connection and the anti-serial

circuit, and the second terminal is electrically connected to the second

current path and between the fourth device connection and the electrical

fuse is arranged, - a control and evaluation device which is connected to the current detection device, wherein the control and evaluation device is designed to

Dependence on the direction detected by the current detection device and

Current, if the detected current reaches or exceeds a predetermined threshold, to switch on the first or second short-circuit switch.

The above mentioned technical problem is also related to the characteristics of the

Claim 2 is resolved.

Accordingly, a DC switching device, in particular for interrupting a

Direct current flow, which can have the following features: - a first and a second device connection, - a first current path which is electrically connected to the first and second device connection, - a third and a fourth device connection, - a second current path which is electrically connected to the third and fourth device connection, - a single electrical fuse, - an anti-serial circuit which has a first controllable semiconductor switch and a second controllable semiconductor switch, wherein a first diode is anti-parallel to the first semiconductor switch and a second diode is anti-parallel to the second

Semiconductor switches are connected, wherein the electrical fuse is arranged in the first current path and the first and second

Semiconductor switches are arranged in the second current path, - a current detection device which is designed to determine the direction and

current intensity of a current flowing through the first or second current path, - a first controllable short-circuit switch having a first terminal and a second terminal, the first terminal being electrically connected to the first

current path and between the second device connection and the electrical

fuse is arranged, and the second terminal is electrically connected to the second

current path and between the third device connection and the anti-serial

Circuit is arranged,

- a second controllable short-circuit switch having a first terminal and a second terminal, the first terminal being electrically connected to the first

current path and between the first device connection and the electrical

fuse is arranged, and the second terminal is electrically connected to the second 5 current path and between the fourth device terminal and anti-serial

Circuit is arranged, - a control and evaluation device which is connected to the current detection device, wherein the control and evaluation device is designed to

Dependence on the direction detected by the current detection device and

Current, if the detected current reaches or exceeds a predetermined threshold, to switch on the first or second short-circuit switch.

The first and second short-circuit switches can, for example, each be designed as a thyristor or triac with a bidirectional current flow.

In order to be able to operate the DC switching device in an energy-saving manner, a mechanical switching contact of an electromechanical switch can be provided, whereby the mechanical switching contact is parallel to the first and second

Semiconductor switch is connected, whereby the control and evaluation device for

designed to control the electromechanical switch. In particular, the

Control and evaluation device ensures that during a switch-on process the corresponding semiconductor switch is first switched on and then the mechanical switching contact is closed.

Especially when using the mechanical switch, the

The short-circuit measure of the invention comes into play. If a short-circuit current occurs when the mechanical switch contact is closed, the reaction time of the electromechanical switch or the mechanical switch contact to open it is so slow, particularly due to its geometry, mass and inertia, that a connected load and/or the DC device can be damaged or even destroyed. The two short-circuit switches in conjunction with the single fuse help here. Because as soon as the control and evaluation device detects a short-circuit current,

short-circuit current and its flow direction, the corresponding

The short-circuit switch is switched on and the short-circuit current is diverted via the only fuse, which then trips quickly. Thanks to the special wiring of the two

Short-circuit switch with the only fuse can minimize the thermal load on the cables up to the location of the short circuit in the event of a short circuit.

Preferably, the first and third device connections can be connected to a

DC power supply and to the second and fourth

Device connection an electrical device or vice versa.

The electrical equipment may be a non-regenerative electrical

Device, such as an ohmic resistor, a regenerative electrical device or another DC voltage supply device. The DC voltage supply device can be, for example, a DC

supply network.

The current detection device can, for example, be a current sensor or

magnetic field sensor. Furthermore, the current detection device can be connected directly into the respective current path. Alternatively, the current detection device can have a shunt resistor and be designed to detect a voltage at the

Shunt resistance and their polarity in order to determine the value of the respective

To determine the current flowing along the current path and its direction.

The current detection device can, for example, be connected in series with the fuse or the anti-serial circuit.

The above technical problem is also caused by the characteristics of the

Claim 8 is resolved.

Accordingly, a DC voltage system is provided which achieves the previously described

DC voltage device. For example, a DC voltage supply device and an electrical load, which can be designed as a regenerative electrical device, can be connected to the DC voltage device. The DC voltage supply device can be, for example, a grounded DC voltage source with a positive pole and a ground connection, a

DC supply network or a DC bus. It should be noted that the

DC device also two DC power supplies, such as

Example two DC supply networks can be connected

According to an advantageous embodiment, the first and second device connection each serve as a positive pole and the third and fourth device connection each serve as a negative pole or

Ground connection, whereby the control and evaluation device of the

DC voltage switching device is designed, for example, to first control the first semiconductor switch to be conductive, particularly during a switch-on process, and at the same time to keep the second semiconductor switch blocked, and then to close the mechanical switching contact when a current is to flow from the first device connection to the third device connection, and to close the first short-circuit switch when the current intensity measured by the current measuring device reaches or exceeds the predetermined threshold value. This is preferably the case when a DC voltage supply device is connected to the first and third device connection and an electrical load that is not capable of regenerative feedback is connected to the second and fourth device connection.

The control and evaluation device can further be designed to first control the second semiconductor switch and at the same time to control the first

Semiconductor switch to keep it locked and then close the mechanical switch contact when a current flows from the second device connection to the fourth

device connection and, if the current measured by the current measuring device

current reaches or exceeds the specified threshold, the second

Short-circuit switch to close. This is preferably the case if an electrical load that is not capable of regenerative power is connected to the first and third device connection and a DC voltage supply device is connected to the second and fourth device connection.

However, if, for example, a

DC power supply and on the second and fourth device connection a regenerative electrical load or a second

DC power supply, the control and

Evaluation device ensure that both the first and the second

Semiconductor switches are switched on because the current direction is not fixed.

The invention is explained in more detail below using two exemplary embodiments in conjunction with the accompanying drawings. For the sake of simplicity of illustration, identical components are provided with identical reference numerals in the drawings.

They show:

Fig. 1 is a circuit diagram of an exemplary DC switching device, and

Fig. 2 shows an alternative circuit diagram of an exemplary DC switching device.

Fig. 1 shows the circuit diagram of an exemplary DC voltage system 5, which has an exemplary DC voltage switching device 10. The DC voltage switching device 10 has a first and a third device connection 11, 12, to which, for example, a DC voltage supply device 100 can be connected. Furthermore, the

DC voltage device 10 has a second and fourth device connection 13, 14 to which an electrical device 90 can be connected. It should be noted that the electrical

Device 90 also to the device connections 11 and 12 and the

DC voltage supply device 100 can be connected to the device terminals 13 and 14. The DC voltage supply device 100 can, for example, be a grounded DC voltage source with a positive pole and a

ground connection, a DC supply network or a DC bus. The electrical device 90 can be designed, for example, as a regenerative or non-regenerative DC load 90 or another

DC voltage supply device.

A first current path 1 runs between the first device connection 11 and the second device connection 13. An anti-serial circuit 60 is connected in the current path 1,

which comprises a first controllable semiconductor switch 61 and a second controllable

semiconductor switch 62 which is connected anti-serially to the first semiconductor switch 61. A first diode 70 is connected anti-parallel to the first semiconductor switch 61 and a second

Diode 71 is connected antiparallel to the second semiconductor switch 62. The two

Semiconductor switches 61, 62 can be designed, for example, as field effect transistors or as

Bipolar transistor with insulated gate electrode (IGBT). In the present example, the two semiconductor switches 61 and 62 are each implemented as n-channel IGBT transistors. The collector

Electrode of the semiconductor switch 61 is connected to the device connection 11, while the collector electrode of the semiconductor switch 62 is connected to the device connection 13. The emitter electrodes of the two semiconductor switches 61 and 62 form a common connection point. The cathode of the diode 70 is connected to the collector

Electrode of the semiconductor switch 61, while the anode of the diode 70 is connected to the emitter electrode of the semiconductor switch 61. Similarly, the cathode of the diode 10 is connected to the collector electrode of the semiconductor switch 62, while the anode of the diode 71 is connected to the emitter electrode of the

semiconductor switch 62. The gate electrodes of the semiconductor switches 61 and 62 are each connected to an input of a control and evaluation device 40, which can be designed as a microcontroller, for example. The control and evaluation device 40 is also connected on the input side to the

Current detection device 30.

A second current path 2, into which an electrical fuse 20 is connected, runs between the third device connection 12 and the fourth device connection 13. It should be noted that the DC voltage switching device 10 only has this one fuse 20.

According to the embodiment shown, a current detection device 30 can be connected in series with the fuse 20 in the second current path 2. However, the current detection device 30 can be connected at any point in the first or second current path 1, 2. For example, the

Current detection device 30 may also have a shunt resistor connected in the first or second current path (not shown). In this case, the

Current detection device may be designed to detect a voltage at the

Shunt resistance and their polarity in order to determine the value of the respective

current flowing through the current path and its direction. It is only important that the

Current detection device 30, however it is implemented, is designed to determine the current intensity and direction of a direct current flowing through the current paths 1 and 2 in order to detect a short-circuit current and its

To recognize the flow direction.

The exemplary connection of the two semiconductor switches 61 and 62 as well as the two diodes 70 and 71 ensures that a) when the first semiconductor switch 61 is electrically conductive and the second

Semiconductor switches 62 are simultaneously electrically blocked, a current from

Device connection 11 via the first semiconductor switch 61, the diode 71, the load 90, the

fuse 20 and the current detection device 30 can flow to the device connection 12, or that, b) when the second semiconductor switch 62 is electrically conductive and the first

Semiconductor switches 61 are simultaneously electrically blocked, a current from

Device connection 13 via the second semiconductor switch 62, the diode 70, the

Device connections 11 and 12, the fuse 20 and the current detection device 30 to the device connection 14.

To prevent inadvertently excessive voltage being applied to the semiconductor switches 61 and 62 during operation,

Blocking voltage is applied, it is advantageous to control both semiconductor switches 61 and 62 simultaneously by the control and evaluation device 40.

Furthermore, the exemplary DC voltage device 10 has two crossing

Short-circuit switches 50 and 51, which are each designed as thyristors, for example. The short-circuit switches 50 and 51 are each connected to an output of the control and evaluation device 40, which is designed, for example, to either switch on the short-circuit switch 50 and leave the short-circuit switch 51 switched off, or vice versa, depending on a detected short-circuit current and its direction.

As can be seen in Fig. 1, the first controllable short-circuit switch 50 has a first

Terminal 50a, which may be designed as an anode terminal, and a second

Connection 50b, which can be designed as a cathode connection. The first

Terminal 50a is electrically connected to the first current path 1 and between the second device terminal 13 and the anti-serial circuit 60 or the collector

Electrode of the semiconductor switch 62. The second terminal 50b is electrically connected to the second current path 2 and between the third

Device connection 12 and a connection of the electrical fuse 20. The

Short-circuit switch 50 further has a control terminal which is connected to an output of the control and evaluation device 40.

The second controllable short-circuit switch 51 has a first terminal 51a, which can be designed as an anode terminal, and a second terminal 51b, which can be designed as

The first terminal 51a is electrically connected to the first current path 1 and is arranged between the first device terminal 11 and the anti-serial circuit 60 or the collector terminal of the

semiconductor switch 61. The second terminal 51b is electrically connected to the second current path 2 and is arranged between the fourth device terminal 14 and another terminal of the electrical fuse 20. The

Short-circuit switch 51 further has a control terminal which is connected to an output of the control and evaluation device 40.

To operate the DC device 10 during operation, i.e. the load 90 is switched on and an electric current flows, for example, from the

In order to be able to switch the DC voltage supply device 100 via the semiconductor switch 61 to the load 90 into an energy saving mode, a mechanical switching contact 81 of an electromechanical switch 80 can be connected in parallel to the first and second

Semiconductor switches 61, 62. The electromechanical switch 80 can be

Relay. According to an exemplary embodiment, the electromechanical switch 80 has an excitation coil 82 which is connected to the control and

evaluation device 40, as shown in Fig. 1. The

Excitation coil 82 is located in a control circuit which is controlled by the control and evaluation device

40 can be controlled accordingly to open and close in order to be able to open or close the mechanical switching contact 81. The switching contact 81 is designed, for example, as a normally open contact.

Fig. 2 shows the circuit diagram of another exemplary DC voltage system 5°, which has an exemplary DC voltage switching device 10°. The

DC voltage switching device 10° has a first and a third device connection 11, 12 to which a DC voltage supply device 100 can be connected.

Furthermore, the DC voltage device 10 has a second and fourth device connection 13, 14 to which an electrical DC voltage load 90 can be connected. It should be noted that the load 90 can also be connected to the device connections 11 and 12 and the

DC voltage supply device 100 can be connected to the device connections 13 and 14, as shown in Fig. 2. The DC voltage switching device 10% differs from the DC voltage switching device 10 in particular only in that an electrical fuse 20 is arranged in the first current path 1 and an anti-serial circuit 60 in the second current path 2. Therefore, in Fig. 1 and Fig. 2 the same

Components are provided with the same reference symbols.

Between the device connection 12 and the second device connection 14 there is a

Current path 2. The anti-serial circuit 60 is connected to the current path 2, which has a first controllable semiconductor switch 61 and a second controllable

semiconductor switch 62 which is connected anti-serially to the first semiconductor switch 61. A first diode 70 is connected anti-parallel to the first semiconductor switch 61 and a second

Diode 71 is connected antiparallel to the second semiconductor switch 62. The two

Semiconductor switches 61, 62 can be designed, for example, as field effect transistors or as

Bipolar transistor with insulated gate electrode (IGBT). In the present example, the two semiconductor switches 61 and 62 are each implemented as n-channel IGBT transistors. The collector

Electrode of the semiconductor switch 61 is connected to the device connection 14, while the collector electrode of the semiconductor switch 62 is connected to the device connection 12. The emitter electrodes of the two semiconductor switches 61 and 62 form a common connection point. The cathode of the diode 70 is connected to the collector

Electrode of the semiconductor switch 61, while the anode of the diode 70 is connected to the emitter electrode of the semiconductor switch 61. Similarly, the cathode of the diode 10 is connected to the collector electrode of the semiconductor switch 62, while the anode of the diode 71 is connected to the emitter electrode of the

semiconductor switch 62. The gate electrodes of the semiconductor switches 61 and 62 are each connected to an input of a control and evaluation device 40, which can be designed as a microcontroller, for example. The control and evaluation device 40 is also connected on the input side to a

Current measuring device 30.

Between the device connection 11 and the device connection 12 there is another

Current path 1, into which the electrical fuse 20 is connected. It should be noted that the

DC switching device 10 has only this one fuse 20. According to the embodiment shown, the current measuring device 30 can be connected in series with the

Fuse 20 must be connected to current path 1. However, the

Current detection device 30 at any point in the first or second

Current path 1, 2. Alternatively, the current detection device 30 can also have a shunt resistor that is connected in parallel to one of the two current paths 1, 2. In this case, the current detection device 30 can be designed to measure a voltage at the shunt resistor (not shown) and its

polarity in order to determine the current flowing through the respective current path and its direction. It is only important that the current detection device 30, however it is implemented, is designed to measure the current intensity and

To determine the direction of a direct current flowing through current paths 1 and 2 in order to detect a short-circuit current and its flow direction.

The exemplary connection of the two semiconductor switches 61 and 62 as well as the two diodes 70 and 71 ensures that a) when the first semiconductor switch 61 is electrically conductive and the second

Semiconductor switches 62 are simultaneously electrically blocked, a current from

Device connection 11 via the first semiconductor switch 61, the diode 71, the load 90, the

fuse 20 and the current detection device 30 can flow to the device connection 12, or that, b) when the second semiconductor switch 62 is electrically conductive and the first

Semiconductor switches 61 are simultaneously electrically blocked, a current from

Device connection 13 via the second semiconductor switch 62, the diode 70, the

Device connections 11 and 12, the fuse 20 and the current detection device 30 to the device connection 14.

Furthermore, the exemplary DC voltage device 10 has two crossing

Short-circuit switches 50 and 51, which can be designed as thyristors or triacs with bidirectional current flow. Such components are characterized by their speed, current carrying capacity and cost structure.

Short-circuit switches 50 and 51 are each connected to an output of the control and

Evaluation device 40 is connected, which is designed, for example, to

Dependence of a detected short-circuit current and its direction either the

To switch on the short-circuit switch 50 and simultaneously switch off the short-circuit switch 51 or vice versa.

As can be seen in Fig. 2, the first controllable short-circuit switch 50 has a first

Terminal 50a, which may be designed as an anode terminal, and a second

Connection 50b, which can be designed as a cathode connection. The first

Terminal 50a is electrically connected to the first current path 1 and is arranged between the second device terminal 13 and a terminal of the fuse 20. The second terminal 50b is electrically connected to the second current path 2 and is arranged between the third device terminal 12 and the collector electrode of the

semiconductor switch 62. The short-circuit switch 50 also has a

Control connection which is connected to an output of the control and evaluation device 40.

The second controllable short-circuit switch 51 has a first terminal 51a, which can be designed as an anode terminal, and a second terminal 51b, which can be designed as

cathode connection. The first connection 51a is electrically connected to the current path 1 and is arranged between the first device connection 11 and a second connection of the fuse 20. The second connection 51b is electrically connected to the current path 2 and is arranged between the fourth device connection 14 and the collector electrode of the semiconductor switch 61. The

Short-circuit switch 51 further has a control terminal which is connected to an output of the control and evaluation device 40.

To protect the DC voltage device 10 during operation, i.e. an electrical current flows

Current, for example, from the DC power supply 100 via the

In order to be able to switch the semiconductor switch 61 to the load 90 into an energy saving mode, a mechanical switching contact 81 of an electromechanical switch 80 can be connected in parallel to the first and second semiconductor switches 61, 62. The electromechanical switch 80 can be designed as a relay. According to an exemplary embodiment, the electromechanical switch 80 has a

Excitation coil 82, which can be connected to the control and evaluation device 40, as shown in Fig. 2. The excitation coil 82 is located in a control circuit, which can be controlled by the control and evaluation device 40 to open and close accordingly in order to open or close the mechanical switching contact 81.

To be able to close. The switching contact 81 is designed as a normally open contact, for example.

A predetermined threshold value is stored in the DC voltage devices 10 and 10°, which defines a short-circuit current. Preferably, the

Control and evaluation device 40 has a memory in which the predetermined

threshold value is stored. The predetermined threshold value can also be stored in a separate memory which the control and evaluation device 40 can access.

It should also be noted that the device connections 11 and 13 can function as positive poles, in which case the current path 1 functions as the positive conductor.

Device connections 12 and 14 can function as negative poles or ground connections, with current path 2 then functioning as a negative conductor or ground line.

The following describes the functionality of the DC devices 10 and 10° in

Connection with the DC voltage system 5 shown in Fig. 1 is explained.

It is assumed that the electrical device 90 is, for example, an electrical, non-regenerative DC load.

Now assume that the DC voltage system 5 or the

DC voltage device 10 is to be activated to connect the electrical load 90 with the

DC voltage supply device 100 to be electrically coupled.

The control and evaluation device 40 is therefore designed to

switching-on process by first switching the semiconductor switch 61 electrically conductive and the semiconductor switch 62 electrically blocking. At this moment, a direct current flows from the direct voltage supply device 100 via the

Device connection 11, the semiconductor transistor 61, the diode 71, through the load 90 and via the device connection 12 back to the DC voltage supply device 100.

If the electromechanical switch 80 is implemented, the control and

Evaluation device 40 causes the DC switching device 10 to close the mechanical switching contact 81, for example after a definable period of time after the semiconductor switch 61 has been switched to conduct. Alternatively or additionally, the control and evaluation device 40 can cause the DC switching device 10 to close the mechanical switching contact 81, for example after a predetermined current threshold has been reached. For this purpose, a threshold value in the

DC switching device 10 to which the control and

The control and evaluation device 40 then compares this threshold value with the current value supplied by the current detection device 30. If the measured current value exceeds the threshold value, the control and evaluation device ensures that the mechanical switching contact 81 is closed. The direction and the current intensity of the direct current is preferably continuously determined by the current detection device 30 and used to

Control and evaluation device 40.

If a short circuit now occurs, both the semiconductor switch 61 would have to be switched off and the mechanical switching contact 81 would have to be opened. However, due to the mechanical construction and the arcing that occurs, the

The reaction time of the electromechanical switch 80 to open the mechanical switching contact 81 is too long to ensure reliable short-circuit resistance. However, thanks to the inventive measure, short-circuit resistance can now be ensured, particularly when using an electromechanical switch.

The control and evaluation device 40 detects the occurrence of a short circuit by the fact that the direct current measured by the current detection device 30 reaches or exceeds the predetermined threshold value. In response to this and to the determined direction of the current flowing from the device connection 11 to the

device connection 13, the control and evaluation device 40 causes the

DC switching device 10, the short-circuit switch 51 is switched on. From this point

Moment the short-circuit current flows through the short-circuit switch 51 and the

Fuse 20 to device connection 12, which triggers fuse 20. Thanks to the special wiring of short-circuit switches 51 and 50 with fuse 20, the load on current paths 1 and 2 and possible connecting cables can be reduced if a short circuit occurs.

It should also be noted that the control and evaluation device 40 can also be designed, for example, to switch on the short-circuit switch 50 after the short-circuit switch 51 has been switched on in order to enable a stepped short-circuit diversion with the aim of directing a current via two paths to the current path 2, which is on

In this way, for example, by means of the second

Short-circuit switch 50 line capacities to load 90 are short-circuited.

In the event that the DC voltage supply device 100 is connected to the

Device terminals 13 and 14 and the load is connected to device terminals 11 and 12, the switch-on process of the DC switching device 10 takes place as follows:

The control and evaluation device 40 is now designed to

switching-on process by first switching the semiconductor switch 62 electrically conductive and the semiconductor switch 61 electrically blocking. At this moment, a direct current flows through the device connection 13, the semiconductor transistor 62, the

Diode 70 and via device terminals 11 and 12 back to device terminal 14. Similarly, a switch-on process can occur when the

DC voltage supply device 100 is connected to the device terminals 11 and 12, and the load 90 connected to the device terminals 13 and 14 is designed to feed energy back to the DC voltage supply device 100.

If the electromechanical switch 80 is implemented, the control and

Evaluation device 40, the DC switching device 10, after a definable

Time period after the semiconductor switch 61 has been switched on, to close the mechanical switching contact 81. The direction and the current strength of the

Direct current is preferably determined continuously by the current determination device 30 and transmitted to the control and evaluation device 40.

The control and evaluation device 40 detects the occurrence of a short circuit when the direct current measured by the current detection device 30 reaches or exceeds the predetermined threshold value. In response to this and to the detected direction of the current flowing from the device connection 13 to the

Device connection 14, the control and evaluation device 40 causes the

DC switching device 10, the short-circuit switch 50. From this point

Moment the short-circuit current flows through the short-circuit switch 50 and the

Fuse 20 to device connection 14, which triggers fuse 20. Thanks to the special wiring of short-circuit switches 51 and 50 with fuse 20, the load on current paths 1 and 2 and possible connecting cables can be reduced if a short circuit occurs.

It should also be noted that the control and evaluation device 40 can also be designed, for example, to switch on the short-circuit switch 51 after the short-circuit switch 50 has been switched on in order to enable a stepped short-circuit diversion with the aim of directing a current via two paths to the current path 2, which is on

In this way, for example, by means of the second

Short-circuit switch 51 line capacitances to load 90 are short-circuited.

Furthermore, it should be noted that advantageously the rated current and overload current of the

Short-circuit switches 50 and 51, the semiconductor switches 61, 62 and the diodes 70, 71 as well as the electromechanical switch 80 to the rated current (i.e. the

tripping characteristic) of the fuse 20. Preferably, the

Dielectric strength of semiconductor switches 61 and 62 is greater than the operating voltage.

The functionality of the DC switching device 10° corresponds essentially to the functionality of the DC switching device 10, so that in order to avoid repetition, the explanations regarding the

DC switching device 10 is referred to.

Claims (10)

Patent claims 1. DC voltage switching device (10), in particular for interrupting a current flow, comprising: - a first and a second device connection (11, 13), - a first current path (1) which is electrically connected to the first and second device connection (11, 13), - a third and a fourth device connection (12, 14), - a second current path (2) which is electrically connected to the third and fourth device connection (12, 14), - a single electrical fuse (20), - an anti-serial circuit (60) which has a first controllable semiconductor switch (61) and a second controllable semiconductor switch (62), wherein a first diode (70) is connected anti-parallel to the first semiconductor switch (61) and a second diode (71) is connected anti-parallel to the second semiconductor switch (62), wherein the electrical fuse (20) is arranged in the second current path (2) and the first and second semiconductor switches (61, 62) are in the first current path (1), - a current detection device (30) which is designed to determine the direction and current intensity of a current flowing through the first or second current path (1, 2), - a first controllable short-circuit switch (50) which has a first connection (50a) and a second connection (50b), wherein the first connection (50a) is electrically connected to the first current path (1) and is arranged between the second device connection (13) and the anti-serial circuit (60), and the second connection (50b) is electrically connected to the second current path (2) and is arranged between the third device connection (12) and the electrical fuse (20), - a second controllable short-circuit switch (51) which has a first connection (51a) and a second connection (51b), wherein the first connection (51a) is electrically connected to the first current path (1) and is arranged between the first device connection (11) and the anti-serial circuit (60), and the second connection (51b) electrically connected to the second current path (2) and arranged between the fourth device connection (14) and the electrical fuse (20), - a control and evaluation device (40) which is connected to the current determination device (30), wherein the control and evaluation device (40) is designed to switch on the first or second short-circuit switch (50, 51) depending on the direction and current intensity detected by the current determination device (30), provided that the detected current intensity reaches or exceeds a predetermined threshold value. 2. DC voltage switching device (10°), in particular for interrupting a current flow, comprising: - a first and a second device connection (11, 13), - a first current path (1) which is electrically connected to the first and second device connection (11, 13), - a third and a fourth device connection (12, 14), - a second current path (2) which is electrically connected to the third and fourth device connection (12, 14), - a single electrical fuse (20), - an anti-serial circuit (60) which has a first controllable semiconductor switch (61) and a second controllable semiconductor switch (62), wherein a first diode (70) is connected anti-parallel to the first semiconductor switch (61) and a second diode (71) is connected anti-parallel to the second semiconductor switch (62), wherein the electrical fuse (20) is arranged in the first current path (1) and the first and second semiconductor switches (61, 62) are arranged in the second current path (2) are arranged, - a current detection device (30) which is designed to determine the direction and current intensity of a current flowing through the first or second current path (1, 2), - a first controllable short-circuit switch (50) having a first connection (50a) and a second connection (50b), the first connection (50a) being electrically connected to the first current path (1) and arranged between the second device connection (13) and the electrical fuse (20), and the second connection (50b) being electrically connected to the second current path (2) and arranged between the third device connection (12) and the anti-serial circuit (60), - a second controllable short-circuit switch (51) having a first connection (51a) and a second connection (51b), the first connection (51a) being electrically connected to the first current path (1) and arranged between the first device connection (11) and the electrical fuse (20), and the second connection (51b) being electrically connected to the second current path (2) and arranged between the fourth device connection (14) and the anti-serial circuit (60), - a control and evaluation device (40) which is connected to the current detection device (30), wherein the control and evaluation device (40) is designed to switch on the first or second short-circuit switch (50, 51) depending on the direction and current intensity detected by the current detection device (30), provided that the detected current intensity reaches or exceeds a predetermined threshold value. 3. DC voltage switching device according to claim 1 or 2, further comprising a mechanical switching contact (81) of an electromechanical switch (80), wherein the mechanical switching contact is connected in parallel to the first and second semiconductor switches (61, 62), wherein the control and evaluation device is designed to control the electromechanical switch (80). 4. DC voltage switching device according to one of the preceding claims, wherein a DC voltage supply device (100) is connected to the first and third device terminals (11, 12) and a DC voltage supply device (100) is connected to the second and fourth Device connection (13, 14) can be connected to an electrical device (90) or vice versa. 5. DC switching device according to one of the preceding claims, wherein the current detection device (30) comprises a current sensor. 6. DC switching device according to one of the preceding claims, wherein the current detection device (30) is connected in series with the fuse (20) or the anti-serial circuit (60). 7. DC switching device according to one of the preceding claims, wherein the first and second short-circuit switches (50, 51) are each designed as a thyristor. 8. DC voltage system (5; 5°) comprising a DC voltage device (10; 10°) according to one of the preceding claims, a DC voltage supply device (90) connected to the DC voltage device (10; 10°) and an electrical device (100) connected to the DC voltage device (10; 10°). 9. DC voltage system (5,;5°) according to claim 8, wherein the first and second device connection (11, 13) are each defined as a positive pole and the third and fourth device connection (12, 14) are each defined as a negative pole, wherein the control and evaluation device (40) of the DC voltage switching device (10; 10°) is designed to first control the first semiconductor switch (61) to be conductive and then to close the mechanical switching contact (81) when a current is to flow from the first device connection (11) to the third device connection (12), and, when the current intensity measured by the current detection device (30) reaches or exceeds the predetermined threshold value, to close the first short-circuit switch (50), or to first control the second semiconductor switch (62) to be conductive and then to close the mechanical switching contact (81) when a current is to flow from the second device connection (13) to the fourth device connection (14), and, when the current intensity measured by the current detection device (30) reaches or exceeds the predetermined threshold value, to close the second short-circuit switch (51). 10. DC voltage system (5; 5°) according to claim 8 or 9, wherein the DC voltage supply device (90) is a DC supply network.