EP1282145A1 - Method and device for self ignitioned pyrotechnical short circuiting - Google Patents

Abstract

The method involves releasing the energy stored in an energy storage device (4). An electrical arc is produced by a voltage between the potential points. Further energy given off by the electrical arc is fed to the energy storage device and release of the energy stored in the storage device is triggered by feeding in the further energy. AN Independent claim is also included for the following: a short circuiting device and a short-circuit proof power semiconducting module.

Description

Technical field

The invention relates to a method for short-circuiting two Potential points according to the preamble of claim 1. Furthermore The invention relates to a short-circuiter according to the preamble of claim 4 and a short-circuit proof power semiconductor module according to the preamble of claim 11th

State of the art

Due to the ever higher power densities in power distribution, Transmission and conversion systems exist in many Situations the risk of undesired training of Arcing or arcing, especially in the event of incorrect switching or incorrect operation, but also in the event of equipment failure or components. In order to cause damage to material or Minimizing people often becomes so-called short-circuiters used a defined short circuit in the event of an error cause. In some applications, this becomes a Opening of a higher-level, power-limiting switch triggered. The short circuiter is necessary because one by one Arcing overcurrent due to resistance of the arc is significantly less than one by one "metallic" short-circuit caused overcurrent; he can even less than e.g. caused by starting large engines Overcurrents. That means a quick release level a normal overcurrent relay in the event of arcing does not work and therefore by means of an overcurrent measurement only protection system in the event of arcing, neither devices people can still be protected.

In order to enable an optimal effectiveness of a short circuiter, it is crucial that a short circuit is as low as possible Time delay caused by the occurrence of the arc becomes. To achieve this, pyrotechnics are often used Switch used where an explosive cartridge has a mechanical Feeds energy for the acceleration of a switching element. DE 9419141 U1 discloses a short-circuiter in which the actual switching element inside the explosive cartridge located. The explosive patrons are ignited in the event of a fault via an ignition cable that is led out through a hole is.

However, this poses the problem of reliable detection of the arc as a decision criterion for tripping the ignition. As mentioned above, a pure Overcurrent measurement due to the high resistance of arcs are not used for their reliable detection. common Arc detectors, e.g. in DE 3890265 T1 for this reason, often measure using a photosensor a light intensity and will be when one is exceeded predetermined threshold active. With some protection systems must have two different physical trigger thresholds - preselected Light intensity and current values - exceeded at the same time so that an event is recognized as an arc becomes. However, such a detection principle is a certain one Inheritance prone to errors. On the one hand, suitable ones Threshold values for light intensity and, if applicable, current can be selected.

On the other hand, appropriate sensors must be from a suitable one Evaluation electronics are monitored. Malfunctions of the sensors, unsuitable selection of trigger thresholds or errors in the evaluation electronics can, however, lead to incorrect behavior of the Short circuit. The presence of evaluation electronics also increases by monitoring and evaluating the measurement signals a response time of the entire protection system. moreover provide sensors and evaluation electronics together with the necessity calibration of the trigger thresholds is a not inconsiderable one Cost factor in the manufacture of such protection systems represents.

However, there are, for example, power electronics also systems in which redundancy is provided at the system level availability even if one or more fail Components or modules guaranteed. Often this requires that failing components / modules into a stable short circuit transition ("short-circuit failure mode", SCFM), in which between two main connections of the component / module permanent electrical contact with the lowest possible resistance and the largest possible electricity capacity. Such components or modules are called short-circuit proof. A Possibility of a short-circuit strength of a component or To achieve module is that between the two Main connections a short circuit is switched, which in the event of an error short-circuits the component or module. In this case arises in addition to the problem already mentioned above the trigger thresholds the problem of contact resistance, which occurs after a release. As is known, the Contact resistance and thus a contact voltage of a metallic Dry contact approximately inversely proportional to the root of a contact pressure. DE 9419141 U1 describes a bolt, who makes contact after the release, in one Wedged end position. DE 19908576 A1 deforms a pyrotechnic Gas generator when an arc occurs gastight, electrically conductive housing plastic, which finally a contact is created. In both cases Contact force and surface, which adjust in the end position, Result of a highly complex dynamic process and thus highly depend on initial conditions. This one Initial conditions due to manufacturing tolerances, temperature changes, Material aging etc. cannot be checked, there are considerable fluctuations in the contact resistance between individual copies of a series.

Presentation of the invention

The present invention is based on the object fast and reliable method for short-circuiting two To create potential points according to the preamble of claim 1, which does not require separate arc detection.

The stated goals are achieved in the process according to claim 1 achieved by a tension between two Potential points one arc creates and a second Energy that the arc emits, an energy store is fed. This second energy then releases the Release of a first stored in the energy store Energy out.

In a preferred embodiment, the arc ignites Pyrotechnic center, which releases large amounts of gas exothermic reaction.

Furthermore, the present invention is based on the object a short-circuiter according to the preamble of claim 4 create that can be produced easily and inexpensively and a safe and permanent short circuit with minimal Establishes contact resistance and in particular the implementation of the method according to claim 1.

This object is achieved in a short-circuiter according to the invention solved according to claim 4 in that one of an arc energy released in a spark gap Energy storage can be supplied and the energy storage through this energy can be released.

Finally, the object of the present invention based on a short-circuit-proof power semiconductor module to create the preamble of claim 11, in which a short-circuiter, especially according to claim 4, in the event of a fault Short circuit causes.

This object is short-circuit proof in accordance with the invention Power semiconductor module according to claim 11 solved in that that one of an arc in a spark gap released energy can be supplied to an energy store and that the energy store can be triggered by this energy.

According to the present invention, these goals are particularly achieved through the elements of the independent claims. Further advantageous embodiments also go from the dependent claims and the description.

Brief description of the figures

Fig. 1 einen Schnitt durch einen erfindungsgemässen Kurzschliesser vor Auslösung eines Energiespeichers.

Fig. 2 einen Schnitt durch einen erfindungsgemässen Kurzschliesser nach Auslösung eines Energiespeichers.

Fig. 3a einen erfindungsgemässen Kurzschliesser mit in einem Kontaktierelement integrierten Verriegelungselementen vor Auslösung eines Energiespeichers in Draufsicht.

Fig. 3b einen Schnitt durch den Kurzschliesser gemäss Fig. 3a längs der Schnittlinie I-II.

Fig. 4a einen Kurzschliesser gemäss Fig. 3a nach Auslösung eines Energiespeichers in Draufsicht.

Fig. 4b einen Schnitt durch den Kurzschliesser gemäss Fig. 4a längs der Schnittlinie I-II.

Fig. 5 ein erfindungsgemässes Leistungshalbleitermodul

Die in den Zeichnungen verwendeten Bezugszeichen und deren Bedeutung sind in der Bezugszeichenliste zusammengefasst.

The invention is explained in more detail below on the basis of exemplary embodiments in conjunction with the drawings. They show schematically:

Fig. 1 shows a section through a short-circuiter according to the invention before triggering an energy store.

Fig. 2 shows a section through a short-circuiter according to the invention after triggering an energy store.

3a shows a short-circuiter according to the invention with locking elements integrated in a contacting element before triggering an energy store in a top view.

3b shows a section through the short-circuiter according to FIG. 3a along the section line I-II.

4a shows a short-circuiter according to FIG. 3a after triggering an energy store in a top view.

4b shows a section through the short circuiter according to FIG. 4a along the section line I-II.

5 shows a power semiconductor module according to the invention

The reference symbols used in the drawings and their meaning are summarized in the list of reference symbols.

Ways of Carrying Out the Invention

In Fig. 1 is a cross section of an embodiment for an inventive short-circuiter according to claim 4 Implementation of the short-circuiting method according to the invention two potential points according to claim 1 shown. The short circuiter has two electrical connections 1a, 1b. This are fixed relative to each other, e.g. through a housing that in the drawing is not shown. A metallic contact element 2b is in a starting position. The Contacting element 2b is movable, whereby the mobility by metallic guide elements 2a and the connections 1a, 1b a shift between the starting position and an ending position is limited. Contacting element and guide elements are preferably radially symmetrical with respect to the axis A. One through the contact element 2b and the connection 1a formed cavity is filled with an energy store 4, that contains a stored first energy. As material for the energy storage come e.g. Standard pyrotechnics in question as they are used in rifle cartridges. A spark gap 3 is between a shape 21 of the contacting element 2b and the connection 1b formed.

If a potential difference between the two connections 1a, 1b exceeds a predetermined ignition voltage V _Zünd , an arc is formed in the spark gap 3. The contacting element 2b is heated by the arc in a region in the vicinity of the formation 21 and thereby ignites the energy store 4. The length of the spark gap 3, ie the minimum distance d between the formation 21 and the connection 1b, determines the value of the ignition voltage. For air, the breakdown field strength E _{max is} approximately E _max = 1 kV / mm, so that the ignition voltage is approximately V _ignition = d E _max . The energy store 4 is preferably able to generate large amounts of gas and / or a shock wave when the first energy stored in it is released. The shock wave or an emerging gas pressure move the contacting element 2b towards the opposite connection 1b. When the contacting element reaches the end position, it forms, together with the guide element 2a, an electrical connection between the first connection 1a and the second connection 1b, as shown in FIG. 2

In a preferred embodiment of the invention, which is shown in FIG. 3a and 3b, contains the contacting element 2b resilient locking elements 5. These serve the Contacting element 2b after triggering the energy storage in to fix an end position (Fig. 4a and 4b). To this end recesses 6 are provided in the guide elements 2a, in which the locking elements 5 jump in when the contact element 2b is in the end position. With help the locking elements 5 and, for example, a suitable one Shape of the contacting element 2b can be the contact pressure can be influenced with which the contacting element 2b in the End position is pressed against the connection 1b. There, like in State of the art described having a contact resistance increasing contact pressure decreases in this way Contact resistance can be minimized.

In a preferred embodiment of the invention, this is Contact element not movable, but is fixed to the Connection 1a connected. The contacting element is off an initial state in which there is no metallic conductive contact exists between the contacting element and the connection 1b, in a final state in which there is a metallic conductive contact caused between the two connections 1a and 1b, deformable. The contacting element is preferably shaped such that it together with the connection 1a forms a container in which the energy storage is located. Are also advantageous Contacting elements that are both movable and deformable are.

In a preferred embodiment of the invention, the Energy store an igniter 7, which is also in Fig. 3b is shown. In a preferred development, the igniter protrudes through a hole in the contact element 2b into the spark gap 3 into it. By one of an arc in the spark gap 3 emitted heat, the igniter 7 is ignited, which then further Components of the energy storage activated, for example a gas generator. It is advantageous with this configuration that that the requirements for the properties of energy storage regarding sensitivity on the one hand, which among other things determines the ignition temperature, and the energy release on the other hand, by the amount and type of releasable Energy and the time required for release, can be influenced and selected independently of each other.

In a preferred embodiment of the invention, a Energy storage used by a pyrotechnic and a Element made of a shape memory alloy (Shape Memory Alloy SMA) contains. The pyrotechnic center is chosen so that at the release of the first energy stored in it primarily heat is produced. This warmth drives again the SMA element. SMAs are below a critical one Temperature in a martensite structure. In the martensite phase they are relatively soft and easily deformable. When warming the SMA go through a transition temperature Phase transition (weak first order) to a more symmetrical one Austenite phase over. In doing so, they deform back into one original condition with a high modulus of elasticity. Stack of SMA disc springs with different transition temperatures are already for gradual pressure generation in a different context been used (US-A-4,897,006). Material and shape of the SMA element are now selected so that the SMA element before the short circuiter is triggered in the martensite phase is present and the contacting element is fixed in the initial state and this with a transition to the austenite phase in the final state emotional. The phase transition is preferably irreversible, so that the contacting element after the phase transition is kept in the final state by the SMA element. The transition temperature is selected in such a way that it can only be heat released by the pyrotechnic center after activation of the pyrotechnic center is reached.

Fig. 5 shows schematically an inventive power semiconductor module according to claim 11, wherein a short-circuiter after Claim 4 is used when an overvoltage is present a short circuit between the connections 1a and 1b to bring about these connections 1a and 1b. Are preferred several IGBT chips 9 with control connections 10 in one Housing combined into a module, with the connections 1a and 1b simultaneously an upper side of the housing and a lower side of the housing form. Close the insulating housing side walls 8a, 8b the housing sideways and define a distance between Top and bottom.

In a preferred embodiment of the invention, the power semiconductor module has instead of the IGBT chips 9 power semiconductors of a different type and / or with a different internal structure on, thyristors or MOSFETs or a combination of different types Power semiconductors.

LIST OF REFERENCE NUMBERS

1a

First connection

1b

Second connection

2a

guide element

2 B

contacting element

3

radio link

4

energy storage

5

locking element

6

Cutout in the guide element

7

fuze

8a, b

Housing side walls

9

IGBT chips

10

control connections

21

Forming the contacting element

Claims (11)

Method for short-circuiting two potential points, under the action of a first energy stored in an energy store (4) when this first energy is released
characterized in that an arc is generated by a voltage between the potential points, and that a second energy, which the arc emits, is supplied to the energy store (4) and a release of the first energy stored in the energy store (4) is triggered by supplying the second energy. A method according to claim 1, characterized in that the release of the stored energy takes place when an exothermic chemical reaction of a fuel contained in the energy store occurs and the release of the stored energy is triggered by supplying an activation energy. A method according to claim 1 or 2, characterized in that the energy store (4) contains a gas generator which generates large amounts of gas when the stored first energy is released. Short-circuiter with two electrical connections (1a, 1b), an energy store (4) with a stored first energy, which is located between the connections (1a, 1b), a contacting element (2b) which, under the action of the stored first energy, releases this first energy can either be moved from an initial position into an end position, with a metallically conductive contact between the connections (1a, 1b) only if the contact element (2b) is in the end position, and / or can be deformed from an initial state into a final state, a metallically conductive contact between the connections only existing if the contacting element (2b) is in the final state, and a spark gap (3), in particular for carrying out a method according to claim 1,
characterized in that a second energy released by an arc in the spark gap (3) can be fed to the energy store (4) and the release of the stored first energy can be triggered by this second energy. Short-circuiter according to claim 4, characterized in that the energy store (4) contains a gas generator which generates large amounts of gas when the stored first energy is released. Short-circuiter according to claim 4 or 5, characterized in that the contacting element (2b) is a multi-part container made of conductive material, in which the energy store (4) is located, the parts of the container can be moved from their starting position into their end position by the stored first energy and can be fixed in the end position by locking elements (5). Short-circuiter according to claim 6, characterized in that the locking elements (5) are resilient locking elements, the locking elements (5) are integrated in a first container part, and that a second container part has recesses (6) which can accommodate the locking elements (5) in the end position. Short-circuiter according to claim 6 or 7, characterized in that the spark gap (3) is formed between the container and one of the two connections (1a or 1b). Short-circuiter according to claim 8, characterized in that the energy store (4) contains an igniter (7) which can be ignited by the second energy released by an arc in the spark gap (3), the igniter (4) protrudes through a hole in the container into the spark gap (3), and that the gas generator can be activated by the igniter (7). Short circuiter according to one of claims 6 to 9, characterized in that the container has two cup-shaped parts which are pushed into one another with openings oriented towards one another. Short-circuit proof power semiconductor module with a first and a second connection (1a, 1b), at least one semiconductor chip (9) which is in electrical connection with a first main electrode with the first connection (1a) and with a second main electrode with the second connection (1b), an energy store (4) with a stored first energy, an electrically conductive contact element (2b), which can be moved from an initial position into an end position by the stored first energy, the contact element (2b) being conductively connected to both connections (1a, 1b) only in the end position, a spark gap (3) in which an arc is formed between the connections when a voltage exceeding a predetermined limit value is present,
characterized in that a second energy released by an arc in the spark gap (3) can be fed to the energy store (4) and that a release of the first energy stored in the energy store (4) can be triggered by this second energy.

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