EP2111628B1 - Electric direct current network for water vessels and for offshore units - Google Patents

Description

The invention relates to an electrical DC network for watercraft, especially for underwater vehicles, as well as for offshore installations according to the preamble of claim 1; Such an electrical DC network is for example from the DE 10 2005 031 761 B3 known.

From the DE 10 2005 031 761 B3 is an electrical DC network of a watercraft, in particular an underwater vehicle, known, in which between a DC power source, such as a battery or a fuel cell system, and an electrical load, such as a traction motor or a vehicle electrical system, a Stromabschalteinrichtung is connected, which is designed as a vacuum switch circuit breaker and comprises a commutation device.

The document DE 1 640 193 discloses a DC network according to the preamble of claim 1.

By the commutation an arc is erasable, which is generated when opening the switch by the current flowing through the switch. For this purpose, the commutation device acts on the vacuum switch immediately after the generation of the arc with an oppositely directed current which compensates for the current flowing in the arc or at least reduces it to such an extent that the arc is extinguished.

The commutation device can be constructed in a variety of ways. By way of example, the commutation device has a commutation circuit lying parallel to the vacuum switch and comprising a switch and a charge store, for example a capacitor. A control device ensures that immediately after the opening of the vacuum switch, the switch is controlled so that the charge storage parallel to the vacuum circuit breaker and reversed polarity is switched to extinguish the arc resulting when opening the arc. Instead of the charge accumulator, a charge generator, such as an electric coil, may be provided, which is controlled by the control device so that it generates a compensation current after opening the vacuum switch, which extinguishes the arc resulting from the opening of the vacuum switch.

Proceeding from this, it is an object of the present invention to develop a DC network according to the preamble of claim 1 such that it is even better suited for use on watercraft, especially underwater vehicles, and offshore installations.

The invention is based on the recognition that current can flow not always only in one direction, but also in the other, opposite direction through a vacuum switch in an electrical DC network. For example, the direction of a short-circuit current through a vacuum switch can basically be indefinite, since it depends on the location of the short circuit in the network. Even in normal operation of the network switching in the network, in the case of an underwater vehicle, for example, to set different driving levels or to switch a battery from feed to load operation, lead to changes in the direction of the current through a vacuum switch. Even in vacuum switches on power couplings, currents of different directions can occur. The direction of the current through the vacuum switch before its opening, and thus also the direction of the current in an emerging when opening the switch arc can thus be different.

In order to ensure a safe switching off of the current even in such different directions of the current through the vacuum switch, the commutation device according to the invention is designed such that it can be erased by arcing currents generated by switch currents of different directions are. This is for example possible because of the commutation counterflows of different directions can be generated and the vacuum switch when opening the switch specifically with the required for the deletion of the resulting arc, the current through the arc oppositely directed, counter-current is applied.

For this purpose, the commutation device can have its own commutation circuit for each of the different current directions. Under a Kommutierungsstromkreis this is understood in general terms a circuit for generating a countercurrent to extinguish an arc. By one of the two commutation circuits, a countercurrent in one direction and by the other of the two commutation circuits, a countercurrent in the other, opposite direction can then be generated, i. E. it can counterflows of different directions to compensate for the arc current can be generated.

Alternatively, the commutation device can have a common commutation circuit for the different current directions, wherein the common commutation circuit can be connected to the vacuum switch differently for the different current directions.

Advantageously, the turn-off device has a device for determining the direction of a current flowing through the vacuum switch. This makes it possible, in the case of an indefinite direction of the current through the switch, to determine the current direction actually present at a given time and to selectively control the one provided for arc quenching in this current direction of one of two commutation circuits or to trigger the correct connection of a common commutation circuit for both current directions.

An even further increase in the switch-off safety is possible because the commutation device is designed in such a way that arcs generated by switch currents of different sizes can be erased. This is possible, for example, by virtue of the fact that countercurrents of different sizes can be generated by the commutation device and, when the switch is opened, the vacuum switch is specifically exposed to a countercurrent with a quantity required for the extinction of the resulting arc.

This is based on the knowledge that in practice the size of the switch current can be very different. Thus, the switch current in the case of a short circuit in the DC network can be more than 25 times the maximum current during normal operation of the DC network. For example, in modern underwater vehicles total short-circuit currents of more than 100kA possible, while the maximum operating current is a maximum of 4 kA. The commutation device thus ensures safe switching off both of the operating currents and of the 25 times higher short-circuit currents. A commutation device designed to switch off operating current would therefore not be able to extinguish an arc generated by a short-circuit current. Conversely, designed for switching off short-circuit currents commutation would apply to the vacuum switch with a much too large countercurrent, which in turn could generate an arc. For a safe extinguishing of an arc, therefore, the countercurrent generated by the Kommutierungseinrichttung must be adjusted in size to the current flowing in the arc switch current.

According to an advantageous embodiment of the invention, the commutation at least for the shutdown of operating currents and for the shutdown of short-circuit currents each have their own commutation circuit.

Alternatively, the commutation can have a common Kommutierungsstromkreis for the shutdown of operating currents and for the switching off of short-circuit currents, each in the common Kommutierungsstromkreis for switching off operating currents and for the shutdown of short-circuit currents different sized countercurrents can be generated.

According to a first advantageous refinement, this common commutation circuit has a charging device for charging a capacitor of the commutation circuit to a maximum expected and disconnected short-circuit current and a discharge device for targeted discharge of the capacitor upon occurrence of a short circuit or a required normal shutdown shortly before triggering a countercurrent pulse.

In accordance with a second advantageous embodiment, this common commutation circuit has a capacitor charging device, by means of which a capacitor of the commutation circuit can be charged to a predeterminable level upon the occurrence of a short circuit or a demanded normal shutdown. As a result, a particularly low weight and volume of the shutdown device can be made possible.

Advantageously, the turn-off device has a device for determining the size of the current flowing through the vacuum switch. This makes it possible to determine the size of the current actually flowing through the switch with indeterminate size of the current through the switch and specifically to generate the counter current required for the arc extinction at this current size.

To further increase the shutdown safety of the vacuum switch may have two mechanically coupled to each other switching poles, wherein one of the switching poles in a branch of a positive pole of the DC power source to the load and the other switching pole in a branch current from a negative pole the DC power source is connected to the consumer, and wherein the turn-off device has its own commutation device for each of the two switching poles. As a result, even double earth faults in a DC network can be switched off. The commutation devices described above are preferably used for the commutation device.

An even further increase in the shutdown safety is possible because the vacuum circuit breaker has three mechanically coupled switching poles, wherein a first of the switching poles in a branch of a positive pole of the DC power source to the load and the other two switching poles in series in a current branch of a negative pole DC source are connected to the consumer, and wherein the turn-off device has its own commutation device for the first switching pole and a separate commutation device together for the other two switching poles. This also double earth faults in a DC network can be switched off. The commutation devices described above are likewise preferably used for the commutation device.

FIG 1

ein Prinzipschaltbild eines elektrischen Gleichstromnetzes eines Unterwasserfahrzeuges mit einer Darstellung unterschiedlicher Stromrichtungen für Betriebsund Kurzschlussströme durch einen Vakuumschalter,

FIG 2

ein Prinzipschaltbild eines Gleichstromnetzes mit einer Abschalteinrichtung mit einem zwischen einer Gleichstromquelle und einem Verbraucher geschalteten Vakuumschalter und einer Kommutierungseinrichtung,

FIG 3

ein Prinzipschaltbild eines Gleichstromnetzes mit einer Kommutierungseinrichtung mit jeweils einem eigenen Kommutierungsstromkreis für unterschiedliche Stromrichtungen,

FIG 4

ein Prinzipschaltbild eines Gleichstromnetzes mit einer Kommutierungseinrichtung mit einem gemeinsamen Kommutierungsstromkreis für unterschiedliche Stromrichtungen,

FIG 5

eine vorteilhafte Ausgestaltung eines Kommutierungsstromkreises,

FIG 6

ein Prinzipschaltbild eines Gleichstromnetzes mit einer Abschalteinrichtung mit einem Vakuumschalter mit zwei Schaltpolen und jeweils einer Kommutierungseinrichtung für jeden der Schaltpole,

FIG 7

ein Prinzipschaltbild eines Gleichstromnetzes mit einer Kommutierungseinrichtung mit jeweils einem eigenen Kommutierungsstromkreis für Betriebsströme und für Kurzschlussströme,

FIG 8

ein Prinzipschaltbild eines Gleichstromnetzes mit einer Kommutierungseinrichtung mit einem gemeinsamen Kommutierungsstromkreis für Betriebsströme und für Kurzschlussströme,

FIG 9

eine erste vorteilhafte Ausgestaltung eines Kommutierungsstromkreises von FIG 8,

FIG 10

eine zweite vorteilhafte Ausgestaltung eines Kommutierungsstromkreises von FIG 8 und

FIG 11

ein Prinzipschaltbild eines Gleichstromnetzes mit einer Abschalteinrichtung mit einem Vakuumschalter mit drei Schaltpolen und einer Kommutierungseinrichtung für einen der Pole und einer Kommutierungseinrichtung gemeinsam für die anderen beiden Pole.

The invention and further advantageous embodiments of the invention according to features of the subclaims are explained in more detail below with reference to exemplary embodiments in the figures; show it:

FIG. 1

a schematic diagram of an electrical DC network of an underwater vehicle with a representation of different current directions for operating and short-circuit currents through a vacuum switch,

FIG. 2

a schematic diagram of a DC network with a turn-off device with a switched between a DC power source and a consumer vacuum switch and a commutation device,

FIG. 3

a schematic diagram of a DC network with a commutation device, each with its own commutation circuit for different current directions,

FIG. 4

a block diagram of a DC network with a commutation device with a common commutation circuit for different current directions,

FIG. 5

an advantageous embodiment of a commutation circuit,

FIG. 6

a schematic diagram of a DC network with a shutdown device with a vacuum switch with two switching poles and one commutation device for each of the switching poles,

FIG. 7

a block diagram of a DC network with a commutation device, each with its own commutation circuit for operating currents and short-circuit currents,

FIG. 8

a block diagram of a DC network with a commutation device with a common commutation circuit for operating currents and short-circuit currents,

FIG. 9

a first advantageous embodiment of a commutation of FIG. 8 .

FIG. 10

a second advantageous embodiment of a commutation of FIG. 8 and

FIG. 11

a schematic diagram of a DC network with a shutdown device with a vacuum switch with three switching poles and a commutation of one of the poles and a commutation together for the other two poles.

An in FIG. 1 shown electrical DC network 1 of an underwater vehicle consists of two sub-networks 2, 3, which are connected to one another via a network coupling 4. The DC network 1 has batteries 5 and generators 6 as DC sources and a traction motor 7 (eg, a DC motor or a DC-powered motor) with two winding systems 8 for driving a propeller 9 of the underwater vehicle and a not-shown electrical system as electrical consumers.

The individual components of the DC power supply are connected to each other via switches 10, 10 ', 11, 11', 12, 12 ', 13. The switches can flow currents of different directions and sizes. For example, when driving the underwater vehicle, the traction motor 7 is powered by the batteries 5, an operating current I _{NF flows} from a battery 5 through the battery switch 10 to the traction motor 7. However, when in charging mode, the batteries 5 are charged by the generators 6, a charging current I flows _NL of a generator 6 through the battery switch 10 in the battery 5. The operating current I _NF and the charging current I _NL are directed in the battery switch 10 opposite.

If, in a first short-circuiting condition Kf1, there is a short-circuit in the winding system 8 of the traction motor 7 fed by the first subnetwork 2, a short-circuit current I _{KF1 flows} from the battery 5 via the battery switch 10 into the traction motor 7. On the other hand, if there is a short circuit in a second short-circuit condition Kf2 in the battery 5, a short-circuit current I _{KF2 flows} from the generator 6 via the battery switch 10 into the battery 5. The short-circuit currents I _KF1 and I _KF2 are directed in the opposite direction in the battery switch 10.

The battery switches 10, 10 'thus have currents of different direction and size off. Also in the case of the mains coupling switch 13 currents of different direction and size are switched off, as both operating currents and short-circuit currents can flow either from the subnet 1 in the subnet 2 or from the subnet 2 in the subnet 1 via the network coupling switch 13.

The switches 10, 10 ', 11, 11', 12, 12 ', 13 are formed as a vacuum switch and each part of a turn-off, the - as in connection with the FIGS. 2 to 11 explained, additionally a commutation device for Extinguish an arc in the vacuum switch has. The two battery switches 10, 10 ', the two generator switches 11, 11' and the two drive motor switches 12, 12 'of a subnetwork 2, 3 need not necessarily each be separate switches, but can also mechanically coupled together poles of a two- or three-pole Be the vacuum switch, ie, the two battery switches 10, 10 'are mechanically coupled together poles of a two- or three-pole battery switch, the two generator switches 11, 11' are mechanically coupled together poles of a two- or three-pole generator switch and the two drive motor switches 12, 12 ' mechanically coupled poles of a two- or three-pole drive motor switch.

FIG. 2 shows in a particularly simplified representation of a subnet 20 of the in FIG. 1 The sub-network 20 has a DC power source 21, an electrical load 22 and a shut-off device 23 for switching off a current flowing between the DC power source 21 and the load 22 current. The switch-off device 23 has a switched between the DC power source 21 and the load 22 vacuum switch 24 and a parallel to the vacuum switch 24 switched commutation 25.

By the commutation 25 an arc in the vacuum switch 24 can be erased, which is generated when opening the switch 24 by current flowing through the switch 24. In this case, the commutation device 25 is embodied such that arcs generated by the switch currents of different directions can be erased. The commutation device 25 extinguishes an arc by generating a countercurrent and the vacuum switch with this countercurrent, ie, a current which is opposite to the current flowing through the arc, and which compensates for the current flowing in the arc or at least reduced so far that the arc comes to extinction. For generating the countercurrent has the commutation device 25 one or more switched Kommutierungsstromkreise 26 (see also FIG. 5 ).

The commutation device 25 can in this case - as in FIG. 3 shown - each have their own commutation circuit 26 for each of the different current directions. The two Kommutierungsstromkreise 26 can hereby be the same structure, but be connected to the vacuum switch 24 with different polarity.

The commutation device 25 can also - as in FIG. 4 shown - have a common for the different directions of commutation circuit 26 which is connected in parallel by means of a switching device 27 for the different current directions, each having a different polarity of the vacuum switch 24. The switching device 27 for changing the polarity of the commutation can be performed both as electromechanically, pneumatically or hydraulically operated mechanical switch or as a bridge circuit of high-power semiconductor switches such. B. high current loadable thyristors.

In both cases, the switch-off device 23 has a device 28 for determining the direction of the current flowing through the switch 24 current. The device 28 controls the Kommutierungsstromkreise 26 by means of one or more control lines 29 (see FIG. 3 ) or the switching device 27 (see FIG. 4 ) depending on the direction of the current flowing through the switch 24.

A commutation circuit 26 itself in this case preferably has - as in FIG. 5 shown - a high-power semiconductor switch 30 for high pulse currents, such as a thyristor, a capacitor 31, a charging device 32 for charging the capacitor 31 and an igniter 33 for igniting the high-power semiconductor switch 30.

At an in FIG. 6 shown shut-off device with increased shutdown safety, the vacuum switch 24 has two mechanically coupled switching poles (ie switching paths) 24a, 24b, wherein the switching pole 24a in a current branch 42 from the positive pole of the DC power source 21 to the load 22 and the switching pole 24b in a current branch 43 from the negative pole the DC power source 21 is connected to the load 22, and wherein the cut-off device 23 each have their own commutation device 25 for each of the two switching poles 24a, 24b. For this purpose, each of the two commutation devices 25 has in each case two commutation circuits 26 for the different current directions through the switching poles 24a, 24b.

As in FIG. 7 In addition, a commutation device 25 may additionally be designed in such a way that arcs generated by switch currents of different sizes can be erased. As a result, the shutdown safety can be further increased. The commutation device 25 has for this purpose a commutation circuit 26a for the generation of countercurrents for extinguishing arcs, which are generated by very high short-circuit currents, and a commutation circuit 26b for the generation of countercurrents for extinguishing arcs, which are generated by relatively low operating currents on. By means of a switching device 40, one of the two commutation circuits 26a, 26b can be selectively switched in parallel to the switch 24. By the commutation 25 counter currents of different sizes are thus generated and the vacuum switch 24 can be acted upon by these countercurrents.

The shut-off device 23 also has a device 41 for determining the size of the current flowing through the vacuum switch. This makes it possible, with an indeterminate magnitude of the current through the switch, to determine the magnitude of the current which actually flows through the switch at a specific time and, depending on the current magnitude, to actuate the switching device 40 in this way, that this specifically switches on the commutation circuit 26a or 26b provided for the arc quenching in this current magnitude in parallel with the switch 24 and triggers the generation of the countercurrent in this commutation circuit.

Alternatively, according to FIG. 8 the commutation device 25 also have a common commutation circuit 26c both for the disconnection of operating currents and for the disconnection of short-circuit currents, wherein in the common commutation circuit 26c for the shutdown of operating currents and for the shutdown of short-circuit currents each different sized countercurrents can be generated.

According to a in FIG. 9 shown particularly advantageous embodiment of the commutation circuit 26c of the capacitor 31 by means of a charging device 32 always charged to the maximum expected and disconnected short-circuit current, but upon occurrence of a short circuit or a required normal shutdown by a condenser 31 connected in parallel unloading 34 shortly before triggering a Commutation current pulses deliberately discharged so far that the resulting commutation has a just sufficient amplitude and time to extinguish the switching arc in the vacuum switch 24. By means of the device 41 for determining the size of the current flowing through the vacuum switch, the amplitude of the expected current to be disconnected and the optimum time for the triggering of vacuum switch 24 and commutation device 25 are determined.

The discharge device 34 is advantageously made of the series connection of a semiconductor switch 35, such. As an IGBT, IGCT or thyristor, and a load resistor 36 which receives the energy to be discharged. The time at which the unloading device 34 is triggered is thereby by the device 41 by electronic means, for. B. a microprocessor control, calculated so that at the time of triggering the Kommutierungsstromimpulses the For this required charge state of the pulse capacitor 31 is reached exactly. In this way it is possible to switch off operating currents and short-circuit currents of very different amplitudes with only a single commutation circuit 26c.

Alternatively - as in FIG. 10 shown - the capacitor 31 are charged only at the occurrence of a short circuit case or a required normal shutdown to the level required in each case; For this purpose, a constantly idling ready capacitor charger 37 is provided, which is characterized in that it has a low electrical continuous load, but a very high short-term load and an electronically adjustable amplitude and preferably also polarity.

For lower short-circuit currents and operating currents, the charging process is terminated by the device 41 at an early stage. The required polarity is also detected by the device 41 and transmitted to the charger 37, so that the capacitor 31 is charged with the appropriate polarity.

This circuit is particularly advantageous if emphasis is placed on low weight and volume of the shutdown device value; for the power semiconductors of the switched commutation circuit while full bridge circuit, but only a parallel circuit 44 is required by two power semiconductors, wherein the respectively required polarity corresponding semiconductor is driven by the device 41 for generating a commutation pulse. Alternatively, both semiconductors can always be driven simultaneously, so that a commutation current, which may vary in polarity, is also carried by the respective other semiconductor switch; As a result, antiparallel freewheeling diodes are no longer needed, which is particularly advantageous in terms of cost, size and weight.

Furthermore, this circuit has the advantage that the capacitor 31 is always acted upon only for a short time with voltage, whereby the same can be built considerably more compact and easier. This is due in particular to the fact that in the case of capacitors loaded with DC voltage, the dielectric must be dimensioned considerably thicker for a low error rate than in the case of capacitors, which are subjected only to pulse voltages.

An in FIG. 11 shown shutdown device 23 has a vacuum switch 24 with three mechanically coupled to each other switching poles 24a, 24b, 24c, wherein the switching pole 24a in a current branch 42 from the positive pole of the DC power source 21 to the load 22 and the switching poles 24b and 24c in series in a current branch 43 from Negative pole of the DC power source 21 are connected to the load 22, and wherein the turn-off device 23 has a commutation device 25 for the switching pole 24a and a commutation 25 together for the two switching poles 24b and 24c. For this purpose, each of the two commutation devices 25 has in each case for each of the two current directions a commutation circuit 26a for the extinction of arcs generated by short-circuit currents, and a commutation circuit 26b for the extinction of arcs generated by operating currents. Alternatively, instead of two commutation circuits 26a and 26b for short-circuit and operating current, a common commutation circuit 26c according to FIG FIGS. 8-10 be provided.

A control device 45 assumes the function of the device 28 of FIG. 4 and the device 41 of FIG. 7 and determines the size and direction of the current through the vacuum switch 24, determines the size required for the arc extinction and polarity of the counter current and controls depending on not shown control lines targeted the or necessary for the generation of this countercurrent commutation and possibly existing charging - / unloaders and switching devices on.

In such an embodiment of the shutdown device 23, a particularly high shutdown safety can be achieved. If there are greater differences in terms of operating currents, it may be useful to provide further commutation circuits to further increase the cut-out safety.

Claims (11)

1. Electric direct current network (1, 20) for surface and submarine water vessels and for offshore units, having at least one direct current source (21), in particular a battery and/or a fuel cell installation, at least one electric consumer (22), e.g. an electric drive motor or an on-board supply network, and at least one cut-off device (23) for cutting off a direct current flowing in the network (1), wherein the cut-off device (23) has a vacuum switch (24) switched into the network (1) and a commutation device (25), by which an electric arc, which is produced by a current which flows through the switch (24) when the switch (24) is opened, can be quenched, characterised in that the commutation device (25) is embodied such that electric arcs from switch currents with a different direction can be quenched by said commutation device.
2. Direct current network (1, 20) according to claim 1, characterised in that the commutation device (25) has a respective separate commutation circuit (26) for each of the different current directions.
3. Direct current network (1, 20) according to claim 1, characterised in that the commutation device (25) has a common commutation circuit (26) for the different current directions, which can be connected to the vacuum switch (24) differently in each case for the different current directions.
4. Direct current network (1, 20) according to one of the preceding claims, characterised in that the cut-off device (23) has a device (28) for determining the direction of a current flowing through the switch (24).
5. Direct current network (1, 20) according to one of the preceding claims, characterised in that the commutation device (25) is embodied such that electric arcs produced by switch currents of different sizes can be quenched.
6. Direct current network (1, 20) according to claim 5, characterised in that the commutation device (25) has a respective separate commutation circuit (26a or 26b) at least for cutting off operating currents and for cutting off short-circuit currents.
7. Direct current network (1, 20) according to claim 5, characterised in that the commutation device (25) has a common commutation circuit (26c) for cutting off operating currents and for cutting off short-circuit currents, wherein reverse currents, each of a different size, can be produced in the common commutation circuit (26c) for cutting off operating currents and for cutting off short-circuit currents.
8. Direct current network (1, 20) according to claim 7, characterised in that the common commutation circuit (26c) has a charging apparatus (32) for charging a capacitor (31) of the commutation circuit (26c) to a maximum short-circuit current to be anticipated and to be cut off and a discharging apparatus (34) for the selective discharge of the capacitor (31) in the case of a short circuit or in the case of a requested normal cut-off shortly before triggering of a reverse current pulse.
9. Direct current network (1, 20) according to claim 7, characterised in that the common commutation circuit (26c) has a capacitor charging device (37), by which a capacitor (31) of the commutation circuit can be charged to a predefinable level in the case of a short-circuit event or a requested normal cut-off.
10. Direct current network (1, 20) according to one of the preceding claims, characterised in that the vacuum switch (24) has two switch poles (24a, 24b) which are mechanically coupled to one another, wherein one of the switch poles (24a) is switched into a current branch (42) from a positive pole of the direct current source (21) to the consumer (22) and the other switch pole (24b) is switched into a current branch (43) from a negative pole of the direct current source (21) to the consumer (22), and wherein the cut-off device (23) has a respective separate commutation device (25) according to one of the preceding claims for each of the two switch poles (24a, 24b).
11. Direct current network (1, 20) according to one of claims 1 to 9, characterised in that the vacuum switch (24) has three switch poles (24a, 24b, 24c) which are mechanically coupled to one another, wherein a first of the switch poles (24a) is switched into a current branch (42) from a positive pole of the direct current source (21) to the consumer (22) and the other two switch poles (24b, 24c) are switched in series into a current branch (43) from a negative pole of the direct current source (21) to the consumer (22), and wherein the cut-off device (23) has a separate commutation device (25) according to one of claims 1 to 9 for the first switch pole (24a) and a separate commutation device according to one of claims 1 to 9 in common for the other two switch poles (24b, 24c).

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