EP1696199A1 - Pulsed power circuit for electromagnetic launcher - Google Patents

Abstract

The switching circuit is for controlling at least one inductor (3) of an electromagnetic projector with an energy storage capacitor (1) for the inductor. There is a switch (2) between the capacitor and inductor and a rectifier (4) switched parallel to the capacitor. The switch is arranged between the rectifier and inductor. The capacitor can be formed by a bank of capacitors.

Description

The present invention relates to a circuit for generating a pulse current for electromagnetic launchers, and more particularly to a modular pulse-current network for multi-dimensional electromagnetic launchers.

For the realization of active armored protective devices, whose mode of operation is based on the law of induction, numerous electromagnetic launcher configurations have been proposed in recent years, see for example "Sterzelmeier, K. and E. Spahn, Distance-Active Electromagnetic Protection Systems (2003), ISL Report R 102 / 2003 ". These are used to pre-accelerate various protective elements and active bodies, such as splitter cassettes, splitter arrays, Blast wave generators, Blendfackein, Nebeigranaten, camouflage, deception and obstruction, cross bars ("flying bars"), solid discs or plates ("flying plates") in round, cuboid or prismatic geometry and lattice or net-shaped structures, depending on the desired end-ballistic effect.

A device for the directional ejection is known from DE 37 295 92 C1. In this case, the directional control is accomplished by providing a plurality of inductor coils which are in different spatial relation to the conductor and which can be controlled individually or in groups by one or more current pulses. This Werfereinrichtungen has in common that the control of the inductors to be acted upon is always the same time, which indeed offers a certain advantage, but also brings disadvantages. On the one hand, the electromechanical efficiency, due to the frame-like Konduktorgeometrie and the associated weak magnetic coupling between inductor and conductor, relatively low. On the other hand, the multipart Induktorsystem requires a complicated structural design.

In contrast, in recent years, a directionally controllable launcher has been studied with a much simpler design, in which the discharge direction is determined by the staggered ignition of a two-part, for example, orthogonal coil system. The time difference may be on the order of one to several hundred microseconds. An orthogonal coil arrangement is suitable for the pulse-shaped acceleration of any protective element and allows the ejection in an angular range of ± 45 ° within a plane, so that a two-dimensional launcher can be realized. The Abwurfinrinkel is a function of the Zündzeitdifferenz between the two coils and the injected energies, the latter are preferably kept constant.

The experiments carried out so far with this arrangement produced quite satisfactory results in the range below 2 × 12 kJ of electrical energy supplied. This applies to the entire angular range, so also for large Zündzeitdifferenzen.

With regard to the intended defense application, however, higher energies to be applied are required with the launcher geometry remaining the same, preferably as far as 2 × 50 kJ with respect to the defense against threats in the mid-caliber range, such as, for example, by projectiles or shaped charges. But even at energies of just over 2 x 12 kJ, and especially in large ignition timing differences, serious problems arise. It turns out that the complete semiconductor switching unit, consisting of diode and thyristor, of the respectively second, ie post-ignition, module is completely destroyed.

The reason for this is that with lifting of the Konduktorsystems also the two excitation coils or inductors themselves interact increasingly with each other, and that, although they are orthogonal to each other, their centers are relatively far apart and therefore only a very small coupling of less than 1%. Obviously, this coupling is sufficient, however, to put the crowbar diode of the respectively post-ignited module at worst in the conductive state, so that it effectively forms a "short circuit" parallel to the second inductor system. But this also means that the capacitor of the post-ignition module discharges during its initiation into the already in the conducting state diode. In the process, this crowbar diode is first of all thermally destroyed because it is abruptly supplied with an excessively high current in the reverse direction, which in turn leads to a high power loss. Subsequently, then the destruction of the thyristor closes due to a high current gradient determined by di / dt. In this way, the current carrying capacity of both components is also exceeded.

It is an object of the present invention to provide a circuit and an electromagnetic projector with such a circuit, which can be controlled non-destructively with a large electrical energy.

This object is solved by the subject matters of the independent claims. Advantageous embodiments will be apparent from the dependent claims.

In principle, the pulse current generation for a multi-dimensional electromagnetic launcher can be realized by at least one of the following four variants, the invention in particular referring to the fourth variant.

In the first variant, the initiation of the respective post-ignition module can be blocked when the flying away Konduktorsystem has already covered a certain way and uses the magnetic coupling between the inductors.

According to a second variant, overshoot-resistant capacitors can be used so that the crowbar diodes can be dispensed with and thus the "inducible short circuit" is avoided.

A third, very simple variant is to wind the two inductor coils in opposite directions so that the crowbar diode of the post-ignition module is in the reverse direction with respect to the voltage induced in this circuit.

A fourth variant according to the invention for achieving the stated object consists in the modification of the pulse-forming network and relates in particular to a pulse-current network or a circuit for controlling at least one inductor or inductor system for an electromagnetic projector with at least one energy store, such as a capacitor or a capacitor bank, for the inductor or the inductor system, which is connected to at least one inductor and, for example, parallel to this is switched, so that a pulse current can flow from the energy storage by the inductor. Between the energy store and the inductor or inductor system is provided at least one switching element, such as a semiconductor switching element for switching high currents, such as a thyristor, GTO, MOS-controlled thyristor (MCT), IGBT or TRIAC to the energy storage with the at least one Electrically connect the inductor and electrically disconnect from this, so that stored in the energy storage electrical energy can be transmitted to the at least one inductor after the activation by the switching element. Furthermore, a current-directing element, such as, for example, a crowbar diode, is connected in parallel with the energy store, in order, for example, to take over the current flowing through the inductor during the slight overshoot of a voltage on the energy store when discharging it. According to the invention, the switching element is provided between the current-directing element, that is, for example, the crowbar diode, and the at least one inductor, so that the current-directing element is connected in parallel with the energy store and the switching element connected in series with the current-directing element abuts against the at least one inductor. The cathode of the diode is connected, for example, to the anode of the thyristor, wherein the cathode of the thyristor is connected to a first terminal and the anode of the diode is connected to a second terminal of the inductor or can be connected.

Preferably, at least one further current-directing element, such as a second diode, is arranged in opposite polarity between the first current-directing element and the energy store, the cathodes or alternatively the anodes of the diodes being connected to one another. Thus, if the energy storage current direction circuit, so for example, the capacitor crowbar diode circuit, can not be designed sufficiently low inductance, the overshoot of the current during discharge can be suppressed by an additional protection diode.

The invention further relates to a circuit or network for driving a multi-dimensional electromagnetic projector with at least two circuits as described above. In this case, preferably, a direction control unit may be provided in order to control the individual circuits in time, for example, with a time interval in the range of one to 1000 microseconds, wherein, for example, two or more thyristors are ignited offset in time, so that the energy storage of the individual sub-circuits in time offset from each other with the respective inductors of the inductor system are connected, whereby a directed ejection of one or more active body can be achieved.

According to a further embodiment, the invention relates to an electromagnetic launcher, as described for example in DE 37 29 592 C1, with a circuit as described above and at least one inductor or inductor system. Preferably, the inductor system consists of two or three orthogonal coils or coil systems and may also comprise four, five or more coils or coil systems. If, for example, a tri-orthogonal coil arrangement is used for constructing a 3D projector, an opening cone with an opening angle of 90 ° can be realized, which is advantageous, for example, for roof protection. Likewise, it is also possible to use four-part or multi-part coil systems, for example with pairwise orthogonal alignment and / or symmetrical coil systems.

Preferably, the electromagnetic launcher has at least one protective element as mentioned above or at least one active body, which can be ejected by the inductor or the inductor system preferably two-dimensionally or three-dimensionally directed.

Thus, with the circuit according to the invention, in particular in cooperation with controllable electromagnetic throwers, a directional control can be maintained in a purely electronic manner and extremely fast, for example in less than 300 microseconds, triggered, compared to the previously known hydraulic or electromagnetic Richtungsstellern whose Time of the order of a few milliseconds or more is a decisive advantage.

For both 2D and 3D throwers, the entire action range of ± 45 ° can be maintained regardless of the number and winding sense of the inductor coils used. The addition of additional coils or inductors is easily possible due to the no longer effective mutual interference and allows the extension of the operational possibilities of an electromagnetic projector according to the invention. In this way, a constructive adaptation of the inductor-conductor system to a specific geometry to be maintained of the protective element or the active body can be achieved.

Figur 1

eine erste Ausführungsform einer erfindungsgemäßen Schaltung als Pulsstrom-Generator, welcher mit einem Induktor gekoppelt ist;

Figur 2

eine zweite Ausführungsform der Erfindung;

Figur 3

ein Prinzipschaltbild zur Veranschaulichung der Kopplung zweier Induktoren;

Figur 4

einen 3D-Werfer aus vier symmetrisch zueinander angeordneten Flachspulen;

Figuren 5a und 5b

eine mögliche Spulenkonfiguration für die in Figur 4 gezeigte Spulenanordnung in Draufsicht und perspektivischer Ansicht; und

Figur 6

eine fünfteilige symmetrische Anordnung von Spulen zur Erhöhung der translatorischen Geschwindigkeitskomponente.

The invention will be described below with reference to preferred embodiments. Show it:

FIG. 1

a first embodiment of a circuit according to the invention as a pulse current generator, which is coupled to an inductor;

FIG. 2

a second embodiment of the invention;

FIG. 3

a schematic diagram illustrating the coupling of two inductors;

FIG. 4

a 3D projector of four symmetrically arranged flat coils;

FIGS. 5a and 5b

a possible coil configuration for the coil arrangement shown in Figure 4 in plan view and perspective view; and

FIG. 6

a five-part symmetrical arrangement of coils to increase the translational velocity component.

FIG. 1 shows the circuit diagram of a pulse-current generator according to the invention, wherein initially only a 1D-projector system is considered for reasons of clarity. The electrical energy to be applied is located in the condenser 1, the is charged to the initial voltage U. At the desired time, the thyristor 2 is ignited and thus the inductor system 3 is connected directly to the energy store 1. As soon as the discharge current I has reached its maximum and the voltage across the capacitor 1 is slightly swung over, the crowbar diode 4 takes over the current flowing through the inductor 3. The thyristor 2 according to the invention is included in the crowbar circuit. Consequently, the crowbar diode 4 is no longer parallel to the inductor 3 but to the capacitor. 1

By this measure, at the same time a particularly compact design of the capacitor crowbar diode circuit is made possible, the inductance can be kept very low, so that it hardly comes to overshoot (<5%) of the capacitor 1. However, if a sufficiently low-inductance structure can not be realized due to constructive conditions, then another protective diode 5 can be inserted into this circuit, as shown in FIG. It should be noted that the blocking voltage of this protective diode 5 need only be designed for the maximum reverse voltage occurring at the capacitor 1 and not for the maximum possible charging voltage on the capacitor first

In the following, further modular pulse-current networks for multi-dimensional launchers will be described, it being noted that the introduction of the protective diodes 5 is also possible without any problems in all circuit variants since they do not influence the time course of the inductor currents in any way and only protect the capacitors 1 serve. For reasons of clarity, these diodes 5 are no longer shown in the individual circuit diagrams.

The procedure of including the thyristor 2 in the crowbar circuit thus initially serves to protect the crowbar diode 4 itself and subsequently to protect the associated thyristor 2. The mode of operation of the thus modified circuit can be described in detail with reference to FIG explain as follows. Here, two identical pulse current generators are shown, which feed a 2D launcher formed by two inductors. As already described, the critical phase is given when the Konduktorsystem and with him the protective element has already covered a certain way and only a small or no magnetic interaction exists more with the respective inductors. Relevant is then only the Coupling between the inductors with each other, as shown symbolically in Figure 3.

Let us first consider the time domain I. This is the phase in which the current I ₁ in the first coil system rises rapidly, with the induction correspondingly increasing in the entire space, ie also in the second inductor. This is to be expressed by the bold line field B expressed. According to the law of induction, a voltage U _2i is then induced in the second module. In the case of the winding sense selected here, however, it will lie in the reverse direction with respect to the crowbar diode there, which does not involve any danger.

As soon as the maximum of l _{1 is} exceeded (time range II), the induction decreases, symbolically indicated here by the somewhat thinner field line. Since the induced voltage is always proportional to the negative derivative of the magnetic flux or the induction, a voltage is now generated in the opposite direction in the second module. However, as long as the thyristor of the second module is in the off state, the voltage U _2i thus induced can not reach the local crowbar diode and consequently can not put it in the conductive state either.

Now, if the second module ignited, the much higher charging voltage U ₂ with respect to the externally induced voltage U _{21 is} opposite and dominant, and it comes in the second module to a "proper" or functionally correct current flow l ₂ through the thyristor, the inductor and further through the crowbar diode.

It should be noted that the transistors in the thus modified circuit have a higher load current integral ∫ | ² dt, since they are now not only during the time period I, but also during the time range II, current-carrying. For this, the pulse current network should be suitably dimensioned and suitable, commercially available thyristor types should be selected.

With a 2D launcher, as shown by way of example in FIG. 3, in which two flat coils are orthogonal to one another, a planar action plane can be swept over. The discharge angle is preferably in the range of -45 ° to + 45 °. Including another coil, which can be arranged triorthogonal, a 3D projector can be realized. Thus, a spatial action cone can be covered with a maximum opening angle of 90 °, which can bring a decisive advantage especially for the roof protection of armored vehicles.

In view of the technical design and taking into account the analytical relationships between the respective Zündzeitverzögerungen and the resulting discharge angle, it is advisable and advantageous to construct a 3D thrower of four symmetrically arranged flat coils, as shown in Figures 4 and 5. FIG. 4 shows the correspondingly expanded pulse-forming network, while FIG. 5a shows a coil configuration which is possible in a plan view and FIG. 5b in a perspective view. As an example, four triangular flat coils are shown here. However, it would also be conceivable that trapezoidal curved coil elements can be used, as they can be cut, for example by means of electroerosion of a hollow conical or bowl-shaped copper blank.

Since the problem of the mutual induction of adjacent coils is generally solved when using the pulse current network according to the invention and the sense of winding of the individual coils remains meaningless, basically any multi-part Werfersysteme can build. For example, FIG. 6 shows a five-part, symmetrical arrangement with a central flat coil in the floor area of the projector. By this measure, if necessary, the operational possibilities can be significantly extended, such as the improvement of the throw accuracy or angular precision in a particular discharge sector or increasing the translational velocity component in the direction of the central axis. The latter is synonymous with an increase in the interaction distance, which is particularly advantageous and known in the defense of shaped charges. The fifth drive coil can thus be added optionally and as needed, ie the type of threat or the desired defense mechanism.

Claims (11)

Circuit for driving at least one inductor (3) of an electromagnetic projector with at least one energy store (1) for the at least one inductor (3) which is connected to the at least one inductor (3), at least one switching element (2) which is connected between the Energy storage (1) and the at least one inductor (3) is arranged, at least one current direction element. (4), which is connected in parallel to the at least one energy store (1), characterized in that the switching element (2) between the current direction element (4) and the at least one inductor (3) is arranged. A circuit according to claim 1, wherein the energy store (1) is a capacitor or a capacitor bank. Circuit according to one of the preceding claims, wherein the switching element (2) is a thyristor, GTO or IGBT. Circuit according to one of the preceding claims with at least one further current direction element (5), which is connected in opposite polarity between the first current direction element (4) and the energy store (1). Circuit according to one of the preceding claims, wherein the current-directing element (4, 5) is a diode, in particular a crowbar diode. Circuit for driving a multi-dimensional electromagnetic projector with at least two circuits according to one of the preceding claims. Circuit according to the preceding claim with a direction control unit for the time-controlled activation of at least two circuits according to one of the preceding claims. Electromagnetic launcher with a circuit according to one of the preceding claims and at least one inductor or inductor system (3). An electromagnetic projector according to the preceding claim, wherein the inductor system consists of two or three orthogonal coils or coil systems or of four, five or more coils or coil systems. Electromagnetic launcher according to one of the two preceding claims, wherein the coils are arranged flat coils, triangular, quadrangular and / or symmetrical to each other and / or a central coil is provided. Electromagnetic launcher according to one of the three preceding claims with at least one protective element or active body, which can be accelerated by the at least one inductor.

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