Short-circuiting device, converter and short-circuiting method

Abstract

An electrical short-circuiting device includes a fixed contact piece and a movable contact piece. The fixed and movable contact pieces are distanced from one another in a basic position and electrically conductively connected to one another in a short-circuit position. A drive transfers the movable contact piece from the basic position into the short-circuit position, and a trigger device includes an electrically driven actuator for triggering the drive.

Claims

1. An electrical short-circuiting device, comprising: a fixed contact piece and a movable contact piece, said fixed and movable contact pieces being distanced from one another in a basic position and being electrically conductively connected to one another in a short-circuit position; a drive configured to transfer the movable contact piece from the basic position into the short-circuit position; and a trigger device including an electrically driven actuator for triggering the drive wherein the actuator comprises a fixed stator which includes a first coil and a rotor which includes a second coil for interaction with the first coil, the rotor and second coil linearly movable along an axis of motion, with the stator and the rotor being arranged along the axis of motion, said first and second coils being configured as air-core coils capable of being actively energized so that the interaction of the first coil with the second coil causes the first coil and the second coil to repel one another, thereby moving the rotor and the second coil along the axis of motion to trigger the drive.

2. The short-circuiting device of claim 1, wherein the trigger device comprises a locking mechanism for locking the drive, said drive being triggered when the electrically driven actuator releases the locking mechanism.

3. The short-circuiting device of claim 2, wherein the actuator comprises a plunger for releasing the locking mechanism.

4. The short-circuiting device of claim 1, wherein the drive comprises a mechanical energy store for supply of energy.

5. The short-circuiting device of claim 1, further comprising an electrically insulating jacket configured to encase the fixed and movable contact pieces.

6. The short-circuiting device of claim 1, wherein the movable contact piece is configured to taper conically in a direction of the fixed contact piece and, when the short-circuit position is reached, enters a complementarily shaped section of the fixed contact piece.

7. The short-circuiting device of claim 1, further comprising a retraction rod configured to transfer the movable contact piece from the short-circuit position into the basic position while energy is supplied to the mechanical energy store at a same time.

8. A converter comprising: a plurality of power modules; and at least one short-circuiting device rendered responsive when one of the power modules fails thereby bridging the failed power module, said at least one short-circuiting device comprising a fixed contact piece and a movable contact piece, said fixed and movable contact pieces being distanced from one another in a basic position and being electrically conductively connected to one another in a short-circuit position, a drive configured to transfer the movable contact piece from the basic position into the short-circuit position, and a trigger device including an electrically driven actuator for triggering the drive, wherein the actuator comprises a fixed stator which includes a first coil, and a rotor which includes a second coil for interaction with, the first coil, the rotor and second coil linearly movable along an axis of motion with the stator and the rotor being as air-core coils capable of being actively energized so that the interaction of the first coil with the second coil causes the first coil and the second coil to repel motion to trigger the drive.

9. The converter of claim 8, wherein the trigger device comprises a locking mechanism for locking the drive, said drive being triggered when the electrically driven actuator releases the locking mechanism.

10. The converter of claim 9, wherein the actuator comprises a plunger for releasing the locking mechanism.

11. The converter of claim 8, wherein the drive comprises a mechanical energy store for supply of energy.

12. The converter of claim 8, wherein the at least one short-circuiting device comprises an electrically insulating jacket configured to encase the fixed and movable contact pieces.

13. The converter of claim 8, wherein the movable contact piece is configured to taper conically in a direction of the fixed contact piece and, when the short-circuit position is reached, enters a complementarily shaped section of the fixed contact piece.

14. The converter of claim 8, wherein the at least one short-circuiting device comprises a retraction rod configured to transfer the movable contact piece from the short-circuit position into the basic position while energy is supplied to the mechanical energy store at a same time.

15. A method for short-circuiting a fixed contact piece with a movable contact piece, said method comprising: activating a short-circuiting device by an electrically driven actuator of a trigger device; and energizing a fixed stator of the actuator, the fixed stator including a first coil and energizing a rotor of the actuator, the rotor including a second coil for interaction with, the first coil, the rotor and second coil linearly movable along an axis of motion, with the stator and the rotor being arranged along the axis of motion, said first and second coils being configured as air-core coils so that the interaction of the first coil with the second coil causes the first coil and the second coil to repel one another thereby moving the rotor and the second coil aeon the axis of motion to trigger a drive of the short-circuiting device to thereby cause the movable contact piece to move from a basic position in which the fixed and movable contact pieces are distanced from one another into a short-circuit position in which the fixed and movable contact pieces are electrically conductively connected to one another.

16. The method of claim 15, further comprising energizing the first coil and the second coil simultaneously.

17. A multilevel converter comprising: a plurality of power modules connected in series; and at least one short-circuiting device rendered responsive when one of the power modules fails thereby bridging the failed power module, said at least one short-circuiting device comprising a fixed contact piece and a movable contact piece, said fixed and movable contact pieces being distanced from one another in a basic position and being electrically conductively connected to one another in a short-circuit position, a drive configured to transfer the movable contact piece from the basic position into the short-circuit position, and a trigger device including an electrically driven actuator for triggering the drive, wherein the actuator comprises a fixed stator which includes a first coil, and a rotor which includes a second coil for interaction with the first coil, the rotor and second coil linearly movable along an axis of motion, with the stator and the rotor being arranged along the axis of motion, said first and second cons being configured as air-core cons capable of being actively energized so that the interaction of the first coil with the second coil causes the first coil and the second coil to repel one another, thereby moving the rotor and the second coil along the axis of motion to trigger the drive.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the following, exemplary embodiments of the invention are shown schematically in drawings and then described in more detail. The drawing shows:

(2) FIG. 1 a schematic view of an electrical short-circuiting device according to a preferred embodiment of the invention,

(3) FIG. 2 a sectional view through the electrical short-circuiting device according to a specific preferred embodiment and

(4) FIG. 3 a sectional view through the actuator of the electrical short-circuiting device according to the specific preferred embodiment of the invention.

(5) FIG. 4 a schematic view of a converter, in particular a multilevel converter, according to a specific preferred embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(6) FIG. 1 is a schematic view of an electrical short-circuiting device 10 according to a preferred embodiment of the invention. The short-circuiting device 10 is a short-circuit switch having a fixed contact piece 12 and a movable contact piece 14. In a basic position (position I shown on the left), the two contact pieces 12,14 are distanced from one another. Furthermore, the short-circuiting device 10 has a drive 16 for transferring, more precisely for moving, the movable contact piece 14 from its basic position into a short-circuit position (position II shown on the right) in which the movable contact piece 14 is electrically conductively connected to the fixed contact piece 12. In order to trigger the drive 16, the short-circuiting device 10 has an electrically triggerable trigger device 18, The trigger device 18 in turn comprises a locking mechanism 20 with a locking pawl 22 and an electrically driven actuator 24.

(7) The processes on the closure of the electrical short-circuiting device 10 are as follows: the electrically driven actuator 24 actuates the locking pawl 22 of the locking mechanism 20 which triggers the drive 16. The drive 16 transfers the movable contact piece 14 from its basic position (position I) into the short-circuit position (position II) in which the movable contact piece 14 is electrically conductively connected to the fixed contact piece 12,

(8) FIG. 2 is a sectional view through the electrical short-circuiting device 10 according to a specific embodiment. Here, it may in particular be identified that the drive 16 has a mechanical energy store 26 for its energy supply, which in the example shown is embodied as a spring arrangement 28, more precisely as a disk spring stack. The corresponding disk springs are each stacked one on top of the other in alternating directions. The stack formed in this way can also be designated a series connection of disk springs. The movable contact piece 14 is in the basic position (position I from FIG. 1), i.e, the disk springs are in a pretensioned state. The movable contact piece 14 is connected to a retraction rod 30. The retraction rod 30 runs through the center of the spring arrangement 28 and is operatively connected to the locking mechanism 20. The pretensioning of the spring arrangement 28 is attached to the locking mechanism 20 which holds the pretensioning in the basic position via the retraction rod 30. For this purpose, the retraction rod 30 is connected to an intermediate element 32 which is supported on one side of the spring arrangement 28 and holds it in the pretensioned state, i.e. compresses it. When the short-circuiting device 10 has been triggered, the movable contact piece 14 is in the short-circuit position (corresponding to position II in FIG. 1) and the spring arrangement 28 is no longer in the pretensioned state or is in a less pretensioned state (not shown). Pulling on the retraction rod 30 can transfer the movable contact piece 14 from the short-circuit position back into the basic position (shown in FIG. 2) and bring the spring arrangement 28 into the pretensioned state.

(9) The electrically driven actuator 24 has a plunger 34 which acts on the locking mechanism 20 when the short-circuiting device 10 is triggered. Herein, the plunger 34 acts on the locking pawl 22 of the locking mechanism 20. In the pretensioned state of the spring arrangement 28, the locking pawl 22 prevents the spring arrangement 28 from leaving its pretensioned state, Only pressure from the plunger 34 on the locking pawl 22 causes the locking mechanism 20 to be released and loosen the spring arrangement 28. The actuator 24, the locking mechanism 20, the retraction rod 30, the spring arrangement 28, the movable contact piece 14 and the fixed contact piece 12 are all located on an axis, namely an axis of motion 36 of the plunger 34 of the actuator 24, which also coincides with the axis of motion of the movable contact piece 14 and the retraction rod 30.

(10) The spring arrangement 28 is surrounded by a housing 38 in which the trigger device 18 is likewise integrated. At the upper end of the housing 38, there is a contacting element 40 which is fastened on the housing 38 by means of screws 42. The contacting element 40 has a central opening in which the movable contact piece 14 is located. In its basic position, the movable contact piece 14 closes in a form-fitting manner with the contacting element 40. The movable contact piece 14 tapers conically in the direction of the fixed contact piece 12 so that when the short-circuit position is reached, it can enter a section of the fixed contact piece 12 which has a complementary shape. In addition, the movable contact piece 12 has a contact piece extension 44 that extends approximately to the intermediate element 32 of the retraction rod 30. In the short-circuit position, this contact piece extension 44 connects the movable contact piece 14 to the contacting element 40 in a conductive manner. The fixed contact piece 12 is fastened on an end piece 48 by means of screwing equipment 46. The end piece 48 forms the upper end of the short-circuiting device 10. The end piece 48 connects the fixed contact piece 12 to an electrically insulating jacket 50. The jacket 50 forms the side end of the short-circuiting device 10. The fixed contact piece 12, the movable contact piece 14, the trigger device 18 and the drive 16 are all encased by the electrically insulating jacket 50. In the region of the trigger device, the housing 38 is surrounded in a form-fitting manner by the jacket 50. At the lower end, the housing 38 protrudes beyond the jacket 50 and extends radially outward. A ring element 52 enclosing the jacket 50 from the outside is fastened to this extension of the housing 38 with screws 42. A housing floor 54 to which the actuator 24 is fastened is integrated in the lower region of the housing 38. Although the individual components of the actuator 24 are already identifiable here in FIG. 2, they will only be discussed in connection with FIG. 3.

(11) FIG. 3 is a sectional view of the actuator 24 which is part of the trigger device 18. The actuator 24 has a stator 56 and a rotor 58. The rotor 58 is connected to the plunger 34 which extends through a stop element 60. The stop element 60 is connected to the stator 56 via connection elements 62. The stator 56 includes a stator base body 64 for receiving a first coil 68. The rotor 58 likewise includes a rotor base body 70 and a second coil 72. The rotor base body 70 has two regions 74, 76. The first region 74 is used to receive the second coil 72 and the second region 76 to stiffen the first region 74. The coils 68, 72 are embodied as flat coils, with two coil packs lying one on top of the other in each case. On the side of the rotor 58 opposite the plunger 34, the rotor has a rotor extension 78 with which it engages in a recess of the stator 56, The rotor 58 is guided in its movement via the plunger 34 and also via the rotor extension 78.

(12) On the actuation of the short-circuiting device 10, the following function results:

(13) At least in respect of their interaction with one another, the two coils 68, 72 should be regarded as air-core coils. Therefore, the action of the actuator 24 is solely based on the Lorentz force which is generated alternately by the interaction between the coil magnetic field of one coil 68, 72 and the current in the other coil 68, 72 and vice versa.

(14) To move the plunger 34, the coils 68, 72 are energized simultaneously such that they are mutually repellent. Since the stator 56 with the first coil 68 is fixed with respect to the actuator 24, the rotor 58 is moved with the second coil 72 along the axis of motion 36 in the direction of the stop element 60 (at the top of the figure). Together with the rotor 58, the plunger 34 serving as an actuating element also moves in this direction.

(15) FIG. 4 is a schematic view of a converter, in particular a multilevel converter 41. A converter, in particular a multilevel converter 41, comprises a plurality of power modules 42 connected in series. The converter, in particular the multilevel converter 41, has at least one short-circuiting device 10, which allows short-circuiting that is as quick and safe as possible. If a power module 42 fails due to an error, it has to be bridged as quickly as possible, as otherwise the entire system can fail. The failed power module 42 is bridged by a short-circuiting device 10.