EP0638160B1 - Mine clearance device - Google Patents

Mine clearance device Download PDF

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Publication number
EP0638160B1
EP0638160B1 EP94904680A EP94904680A EP0638160B1 EP 0638160 B1 EP0638160 B1 EP 0638160B1 EP 94904680 A EP94904680 A EP 94904680A EP 94904680 A EP94904680 A EP 94904680A EP 0638160 B1 EP0638160 B1 EP 0638160B1
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EP
European Patent Office
Prior art keywords
capacitor
coil
capacitance
circuit
voltage source
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EP94904680A
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German (de)
French (fr)
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EP0638160A1 (en
Inventor
Loic Laine
Philippe Arnaud
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Giat Industries SA
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Giat Industries SA
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
    • F41H11/00—Defence installations; Defence devices
    • F41H11/12—Means for clearing land minefields; Systems specially adapted for detection of landmines
    • F41H11/16—Self-propelled mine-clearing vehicles; Mine-clearing devices attachable to vehicles

Definitions

  • the field of the present invention is that of demining devices, and more particularly that of devices intended to initiate a mine with magnetic influence from a distance.
  • Such devices are known, for example from patent DE3444037, the description of which is taken from the preamble of independent claim 1. They comprise a coil generating a magnetic field which is fixed to the front part of a demining vehicle, for example a tank.
  • This coil is connected to an electrical supply circuit which supplies a current making it possible to generate the magnetic field.
  • the electrical supply circuit makes it possible to give the supply current a shape such that the magnetic field generated by the coil is close to that of the vehicle to be simulated.
  • the shape of the current is provided by an electronic memory which controls a power generator.
  • the energy consumption will be all the more important when one seeks to initiate mines at a long distance from the vehicle, or when one wishes to circulate the latter at high speeds.
  • the patent US3707913 describes a naval demining device which generates a high intensity electromagnetic field intended to cause the initiation of the pyrotechnic components of the mine by generating induced currents. Such a device also consumes a great deal of energy.
  • the invention also makes it possible to provide in a simple manner a magnetic field close to the field generated by a real vehicle. It is therefore no longer necessary to have recourse to an electronic memory controlling a power generator as in the device described by DE3444037.
  • the invention therefore thus provides a simpler demining device (therefore more rustic and less expensive) than known devices, without such a simplification causing degradation of demining performance.
  • the subject of the invention is a demining device intended to initiate a mine with magnetic influence from a distance and comprising a coil generating a magnetic field and an electrical supply circuit for the latter, this device characterized in that the circuit of power supply comprises a capacity mounted in parallel on the terminals of the coil and switch means making it possible to connect and disconnect this capacity to a voltage source, the switch means ensuring periodically a sequence comprising a connection during a first time interval tl intended to allow establishing a current in the coil, connection followed by disconnection during a second time interval t2 during which the circuit constituted by the capacitor and the coil is a damped oscillating circuit.
  • the switching means comprise a transistor whose Drain (D) is connected to the capacitor and the Source (S) is connected to the voltage source, the base (G) of this transistor receiving slots voltage supplied by an electronic control circuit.
  • the capacity consists of two electrochemical capacities mounted in series and connected to one another by one of their electrodes of the same sign, each capacity being short-circuited by a diode allowing current to flow through an opposite direction to that of the capacity considered.
  • the voltage source comprises a capacitor and the switch means are switch means which ensure, when the capacitor is disconnected, the connection of the capacitor to a load supply.
  • the switching means comprise two transistors, the respective bases of which each receive a different control signal supplied by a control generator, a first transistor being intended to ensure the periodic connection and disconnection of the capacitor to the capacitor. , a second transistor being intended to ensure the periodic connection and disconnection of the capacitor to the load supply.
  • a demining device 1 comprises a coil 2 formed in a known manner by winding a wire 3 on a support 4
  • the support is intended to be made integral with the front part of a vehicle not shown.
  • the connection is made by means of, for example, flanges (not shown).
  • the ends 3a and 3b of the coil wire constitute the terminals of the coil 2.
  • a supply circuit 5 for this coil comprises a capacitor 6, which is mounted in parallel on the terminals 3a and 3b of the coil.
  • the capacitor 6 is connected to a voltage source 7 by means of switch means 8.
  • FIG. 2 represents the current I flowing in the coil 2 as a function of time t.
  • the switching means 8 are actuated so as to connect the voltage source 7 to the capacitor 6. This charges and the current flowing in the coil 2 increases to a maximum value Imax which is reached at the end of time t1.
  • the circuit constituted by the capacitor 6 and the coil 2 then becomes an oscillating circuit, the current which circulates in the coil is sinusoidal of damped amplitude.
  • the shape of the current obtained makes it possible to generate in the coil a magnetic field of similar shape and which approaches the magnetic signature of a real vehicle.
  • a coil will preferably be chosen such that its ratio R / 2L (where R is the resistance of the coil and L its inductance) is between 8 and 12. Such values make it possible to obtain coils whose the damping time constant is between 80 and 120 milliseconds.
  • capacitance C such that the free oscillation frequency of the capacitance-coil circuit is between 10 and 20 Hz.
  • a capacitance of the order of 0.01 Farad gives satisfaction for a coil whose inductance is of the order 50 milli Henry.
  • the duration tl chosen will be of the order of 200 milliseconds, or approximately two damping time constants of the coil.
  • the circuit will then be left to oscillate for 5 to 10 periods of the capacity-coil oscillating circuit (i.e. between 0.5 and 1 second for a frequency of 10 Hz).
  • the device thus described consumes less energy than the known devices.
  • the power saving obtained with the device according to the invention can be greater than or equal to 50%. It will depend in a way general characteristics of the coil. With the values given previously by way of example, the power saving is of the order of 70%.
  • FIG. 3 represents a diagram of switch means 8 which can be used in the device according to the invention.
  • the coil 2 is shown schematically in this figure.
  • These switching means 8 comprise a transistor 11 of the MOS ("Metal Oxide Semiconductor") type, the Drain (D) of which is connected to the capacitor 6 and the Source (S) of which is connected to the voltage source 7.
  • MOS Metal Oxide Semiconductor
  • the base (Gate G) of the transistor 11 receives signals supplied by an electronic control circuit 12.
  • the latter is supplied by the voltage source 7 and it delivers a signal consisting of voltage slots of width equal to t1 and of period equal to t2.
  • the control circuit 12 also includes a switch (not shown here) and allowing the device to be started or stopped.
  • the amplitude of the voltage slots will be adapted to the characteristics of the MOS transistor 11, it is usually of the order of 5 volts.
  • a resistor 13 connects the base G to the voltage source 7, its function is to adapt the impedance of the control circuit 12 with the gate of the MOS.
  • control circuit 12 when the control circuit 12 is started, it delivers a signal comprising slots of duration t1 which follow one another with a period t2.
  • the rising edge of the first slot applied to the base G of the transistor 11, allows the passage of current from the Source S to the Drain D.
  • the switch means 8 then ensure the connection of the capacitor 6 to the voltage source 7.
  • the capacity 6 is then charged by the voltage source 7 as described above.
  • the base G of the transistor 11 receives the falling edge of the first slot provided by the control circuit 12.
  • control means apply to transistor 11 a second time slot of duration t1. This results in a new connection followed by a disconnection.
  • switch means 8 could be envisaged, for example a static relay or an electromechanical relay.
  • FIG. 4 represents an alternative embodiment of the device according to the invention.
  • the capacity 6 is replaced by two electrochemical capacities 6a and 6b which are connected in series and connected to one another by one of their electrodes of the same sign, here the negative electrodes 9a and 9b.
  • Each capacitor is short-circuited by a diode 10a, 10b which allows current to flow in the opposite direction to that of the capacitor considered.
  • the current curve flowing in the coil 2 which is obtained with this variant is of the same type as that described previously with reference to FIG. 2.
  • the capacitors When connecting the capacitors to the voltage source 7, the latter will charge the capacitor 6b.
  • the capacitor 6a will be charged during the first oscillation of the oscillating circuit constituted by the capacitors and the coil.
  • FIG. 5 represents a second embodiment of the device according to the invention.
  • the voltage source consists of a capacitor 14.
  • the switching means are switching means 15, that is to say means which ensure on the one hand the connection and disconnection of the capacitor 6 to the voltage source constituted by the capacitor 14, and on the other hand the connection of the capacitor 14 to a load supply 16, when the capacity 6 is disconnected.
  • the switch 15 connects the capacitor 14 to the load supply 16 (which is for example constituted by a battery).
  • the upper curve 17 represents the variations in the charging current Ic of the capacitor 14 over time. This current reaches its maximum Icmax at the end of time t'0.
  • the capacitor 14 then charges the capacitor 6 for the duration t'1-t'0.
  • the current flowing in the coil 2 increases to a maximum value Imax which is reached at the end of time t'1-t'0 (see lower curve 18).
  • the capacitor 14 discharges completely in the capacitor 6 and the coil 2.
  • the circuit constituted by the capacitor 6 and the coil 2 then becomes an oscillating circuit, the current which circulates in the coil is sinusoidal of damped amplitude.
  • the shape of the current obtained makes it possible to generate in the coil a magnetic field of similar shape and which approaches the magnetic signature of a real vehicle.
  • the charging time will be chosen such that it is possible to reconnect the capacitor 14 to the coil 2 after a time t'2-t'1. This connection will be made for a new period t'1-t'0 necessary for establishing the current in the coil, the capacitor 14 is then again disconnected from the capacitor 6.
  • the capacitor 14 will in all cases have a capacity C1 greater than that C of the capacity 6.
  • C1 will be determined as a function of the inductance L and the resistance R of the coil 2 so that the circuit formed by the capacitor 14 and coil 2 is critical aperiodic which means that C1 will be such that LC1 is equal to (2L / R) 2 .
  • the charge time t'1-t'0 is always of the order of 200 milliseconds, ie approximately two damping time constants of the coil.
  • the circuit oscillates for 5 to 10 periods of the capacity-coil oscillating circuit (i.e. between 0.5 and 1 second for a frequency of 10 Hz).
  • This oscillation time is sufficient to allow recharging of the capacitor 14 by the load supply 16.
  • the device according to this second embodiment of the invention consumes less energy than the known devices.
  • the main advantage of this embodiment compared to the previous one is that it makes it possible to limit the value of the maximum discharge current of the vehicle battery.
  • the battery constituted the voltage source 7 connected to the capacitor 6, it saw a current of the order of 20 amperes.
  • the battery constitutes the charge supply 16. It is then connected to the capacitor 14 for a longer period (of the order of 100%) which makes it possible to limit the intensity delivered by the 10 Amp battery.
  • FIG. 7a represents an example of switching means 15 usable in this second embodiment.
  • These switching means comprise two MOS type transistors 20 and 21, the respective bases G1 and G2 each of which receive a different control signal supplied by a command generator 22.
  • the command generator 22 also includes a switch (not shown) intended to enable the device to be started and stopped.
  • the transistor 20 receives a signal S1 and the transistor 21 a signal S2.
  • the command generator 22 is supplied with energy by the load supply 16 (constituted for example by a vehicle battery).
  • Resistors 23 and 24 are arranged between the bases G1 and G2 of the transistors 20 and 21 and the load supply 16. Their function is to adapt the impedance of the control generator 22 with the bases of the transistors.
  • the transistor 20 is intended to ensure the connection of the capacitor 14 to the load supply, the transistor 21 makes it possible to connect the capacitor 14 to the coil 2 (shown diagrammatically).
  • FIG. 7b shows the signals S1 and S2 which are applied by the command generator 22 to the transistors 20 and 21.
  • the signal S1 (top curve) consists of a series of slots of width t'0, the signal S2 (bottom curve) of a series of slots of width t'1-t'0.
  • the two signals have the same period equal to t'1.
  • the amplitude of the voltage slots is adapted to the characteristics of the MOS transistors, it is usually of the order of 5 volts.
  • transistor 20 makes the connection of capacitor 14 and of load power 16. This connection is maintained for the duration t'0 which allows the charging of the capacitor 14 (see FIG. 6).
  • the transistor 21 receives no signal at its base G2 and therefore isolates the capacitor 14 from the coil 2.
  • the transistor 20 becomes insulating while the transistor 21 receives the rising edge of the first slot of the signal S2.
  • the transistor 21 then makes the connection of the capacitor 14 to the coil 2 and this for the time t'1-t'0, time necessary for the establishment of the current in the coil 2.
  • the transistor 21 becomes insulating again, allowing the damped sinusoidal regime to be established in the circuit constituted by the capacitor 6 and the coil 2.
  • the signal S1 has commanded the connection of the capacitor 14 and the load supply 16, thus allowing the latter to be recharged.
  • the switching cycle can be repeated indefinitely.
  • Switches 15 could be envisaged, for example using static relays or electromechanical relays.

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  • General Engineering & Computer Science (AREA)
  • Engineering & Computer Science (AREA)
  • Control Of Charge By Means Of Generators (AREA)
  • Control Of Eletrric Generators (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Excavating Of Shafts Or Tunnels (AREA)
  • Locating Faults (AREA)
  • Insulators (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
  • Surgical Instruments (AREA)
  • Paper (AREA)
  • Current-Collector Devices For Electrically Propelled Vehicles (AREA)

Abstract

PCT No. PCT/FR94/00050 Sec. 371 Date Aug. 30, 1994 Sec. 102(e) Date Aug. 30, 1994 PCT Filed Jan. 14, 1994 PCT Pub. No. WO94/18520 PCT Pub. Date Aug. 18, 1994.An apparatus for activating a magnetic influenced mine from a distance includes a circuit arrangement for conserving power use and simulating the magnetic signature of a vehicle. The circuit arrangement includes a magnetic field generating coil connected to an electric feed circuit. The electric feed circuit is comprised of a voltage source, a circuit breaking element, and at least one capacitor connected to the terminals of the magnetic field generating coil. The circuit breaking element operates to alternately connect and disconnect the set of capacitors from the voltage source. By oscillating the current to the magnetic generating coil, the magnetic signature of a vehicle is simulated, and a mine is fooled into activation.

Description

Le domaine de la présente invention est celui des dispositifs de déminage, et plus particulièrement celui des dispositifs destinés à initier à distance une mine à influence magnétique.The field of the present invention is that of demining devices, and more particularly that of devices intended to initiate a mine with magnetic influence from a distance.

De tels dispositifs sont connus, par exemple par le brevet DE3444037 dont l'exposé est pris à base du préambule de la revendication indépendante 1. Ils comprennent une bobine génératrice de champ magnétique qui est fixée à la partie avant d'un véhicule de déminage, par exemple un char.Such devices are known, for example from patent DE3444037, the description of which is taken from the preamble of independent claim 1. They comprise a coil generating a magnetic field which is fixed to the front part of a demining vehicle, for example a tank.

Cette bobine est reliée à un circuit d'alimentation électrique qui fournit un courant permettant de générer le champ magnétique. Généralement le circuit d'alimentation électrique permet de donner au courant d'alimentation une forme telle que le champ magnétique engendré par la bobine soit proche de celui du véhicule à simuler.This coil is connected to an electrical supply circuit which supplies a current making it possible to generate the magnetic field. Generally the electrical supply circuit makes it possible to give the supply current a shape such that the magnetic field generated by the coil is close to that of the vehicle to be simulated.

La forme du courant est fournie par une mémoire électronique qui pilote un générateur de puissance.The shape of the current is provided by an electronic memory which controls a power generator.

L'inconvénient majeur d'un tel dispositif de déminage est qu'il consomme énormément d'énergie, ainsi les dispositifs démineurs existant consomment plus de 2000 Watts de façon continue.The major drawback of such a demining device is that it consumes a lot of energy, so existing demining devices consume more than 2000 Watts continuously.

Avec une telle consommation il n'est pas possible d'utiliser un tel dispositif de déminage longtemps sans nuire aux caractéristiques opérationnelles du véhicule.With such consumption it is not possible to use such a demining device for a long time without harming the operational characteristics of the vehicle.

De plus, la consommation d'énergie sera d'autant plus importante que l'on cherchera à initier les mines à grande distance du véhicule, ou que l'on souhaitera faire circuler ce dernier à des vitesses importantes.In addition, the energy consumption will be all the more important when one seeks to initiate mines at a long distance from the vehicle, or when one wishes to circulate the latter at high speeds.

Le brevet US3707913 décrit un dispositif de déminage naval qui engendre un champ électromagnétique de forte intensité destiné à provoquer l'initiation des composants pyrotechniques de la mine en engendrant des courants induits. Un tel dispositif consomme également énormément d'énergie.The patent US3707913 describes a naval demining device which generates a high intensity electromagnetic field intended to cause the initiation of the pyrotechnic components of the mine by generating induced currents. Such a device also consumes a great deal of energy.

C'est le but de la présente invention que de proposer un dispositif de déminage consommant moins d'énergie que les dispositifs existants.It is the aim of the present invention to propose a demining device consuming less energy than existing devices.

L'invention permet également de fournir d'une façon simple un champ magnétique proche du champ engendré par un véhicule réel. Il n'est donc plus nécessaire d'avoir recours à une mémoire électronique pilotant un générateur de puissance comme dans le dispositif décrit par DE3444037.The invention also makes it possible to provide in a simple manner a magnetic field close to the field generated by a real vehicle. It is therefore no longer necessary to have recourse to an electronic memory controlling a power generator as in the device described by DE3444037.

L'invention propose donc ainsi un dispositif de déminage plus simple (donc plus rustique et moins coûteux) que les dispositifs connus, sans qu'une telle simplification n'entraîne de dégradation des performances de déminage.The invention therefore thus provides a simpler demining device (therefore more rustic and less expensive) than known devices, without such a simplification causing degradation of demining performance.

Ainsi l'invention a pour objet un dispositif de déminage destiné à initier à distance une mine à influence magnétique et comprenant une bobine génératrice de champ magnétique et un circuit d'alimentation électrique de cette dernière, ce dispositif caractérisé en ce que le circuit d'alimentation comprend une capacité montée en parallèle sur les bornes de la bobine et des moyens interrupteurs permettant de connecter et déconnecter cette capacité à une source de tension, les moyens interrupteurs assurant périodiquement une séquence comprenant une connexion pendant un premier intervalle de temps tl destiné à permettre l'établissement d'un courant dans la bobine, connexion suivie d'une déconnexion pendant un deuxième intervalle de temps t2 pendant lequel le circuit constitué par la capacité et la bobine est un circuit oscillant amorti.Thus the subject of the invention is a demining device intended to initiate a mine with magnetic influence from a distance and comprising a coil generating a magnetic field and an electrical supply circuit for the latter, this device characterized in that the circuit of power supply comprises a capacity mounted in parallel on the terminals of the coil and switch means making it possible to connect and disconnect this capacity to a voltage source, the switch means ensuring periodically a sequence comprising a connection during a first time interval tl intended to allow establishing a current in the coil, connection followed by disconnection during a second time interval t2 during which the circuit constituted by the capacitor and the coil is a damped oscillating circuit.

Selon un mode particulier d'exécution, les moyens interrupteurs comprennent un transistor dont le Drain (D) est connecté à la capacité et la Source (S) est reliée à la source de tension, la base (G) de ce transistor recevant des créneaux de tension fournis par un circuit électronique de commande.According to a particular embodiment, the switching means comprise a transistor whose Drain (D) is connected to the capacitor and the Source (S) is connected to the voltage source, the base (G) of this transistor receiving slots voltage supplied by an electronic control circuit.

Selon une variante d'exécution, la capacité est constituée par deux capacités électrochimiques montées en série et reliées l'une à l'autre par une de leurs électrodes de même signe, chaque capacité étant court circuitée par une diode permettant un passage de courant dans un sens inverse de celui de la capacité considérée. Selon un deuxième mode de réalisation de l'invention, la source de tension comprend un condensateur et les moyens interrupteurs sont des moyens commutateurs qui assurent, lors de la déconnexion de la capacité, le raccordement du condensateur à une alimentation de charge.According to an alternative embodiment, the capacity consists of two electrochemical capacities mounted in series and connected to one another by one of their electrodes of the same sign, each capacity being short-circuited by a diode allowing current to flow through an opposite direction to that of the capacity considered. According to a second embodiment of the invention, the voltage source comprises a capacitor and the switch means are switch means which ensure, when the capacitor is disconnected, the connection of the capacitor to a load supply.

Selon un mode particulier d'exécution, les moyens commutateurs comprennent deux transistors dont les bases respectives reçoivent chacune un signal de commande différent fourni par un générateur de commande, un premier transistor étant destiné à assurer la connexion et la déconnexion périodique de la capacité au condensateur, un deuxième transistor étant destiné à assurer la connexion et déconnexion périodique du condensateur à l'alimentation de charge.According to a particular embodiment, the switching means comprise two transistors, the respective bases of which each receive a different control signal supplied by a control generator, a first transistor being intended to ensure the periodic connection and disconnection of the capacitor to the capacitor. , a second transistor being intended to ensure the periodic connection and disconnection of the capacitor to the load supply.

L'invention sera mieux comprise à la lecture de la description qui va suivre de modes particuliers de réalisation, description faite en référence aux dessins annexés et dans lesquels:

  • la figure 1 représente un schéma de principe d'un dispositif de déminage selon l'invention,
  • la figure 2 est une courbe donnant la forme du courant circulant dans la bobine du dispositif selon l'invention,
  • la figure 3 représente un schéma d'un moyen interrupteur utilisé dans le dispositif selon l'invention,
  • la figure 4 représente un schéma de principe d'une variante d'un dispositif de déminage selon l'invention,
  • la figure 5 représente un schéma de principe d'un deuxième mode de réalisation d'un dispositif de déminage selon l'invention,
  • la figure 6 présente deux courbes qui donnent, pour un dispositif selon le deuxième mode de réalisation de l'invention, d'une part l'intensité de charge du condensateur d'alimentation et d'autre part la forme du courant circulant dans la bobine,
  • la figure 7a représente un schéma d'un moyen commutateur utilisé dans le dispositif selon le deuxième mode de réalisation de l'invention,
  • la figure 7b donne la forme des créneaux délivrés par le générateur de commandes.
The invention will be better understood on reading the description which follows of particular embodiments, description made with reference to the appended drawings and in which:
  • FIG. 1 represents a block diagram of a demining device according to the invention,
  • FIG. 2 is a curve giving the shape of the current flowing in the coil of the device according to the invention,
  • FIG. 3 represents a diagram of a switch means used in the device according to the invention,
  • FIG. 4 represents a block diagram of a variant of a demining device according to the invention,
  • FIG. 5 represents a block diagram of a second embodiment of a demining device according to the invention,
  • FIG. 6 presents two curves which give, for a device according to the second embodiment of the invention, on the one hand the charge intensity of the supply capacitor and on the other hand the shape of the current flowing in the coil ,
  • FIG. 7a represents a diagram of a switching means used in the device according to the second embodiment of the invention,
  • FIG. 7b gives the form of the slots delivered by the command generator.

En se reportant à la figure 1, un dispositif de déminage 1 selon l'invention comprend une bobine 2 constituée de façon connue par un enroulement d'un fil 3 sur un support 4Referring to Figure 1, a demining device 1 according to the invention comprises a coil 2 formed in a known manner by winding a wire 3 on a support 4

Le support est destiné à être rendu solidaire de la partie avant d'un véhicule non représenté. La solidarisation est réalisée au moyen par exemple de brides (non représentées).The support is intended to be made integral with the front part of a vehicle not shown. The connection is made by means of, for example, flanges (not shown).

Les extrémités 3a et 3b du fil de la bobine constituent les bornes de la bobine 2.The ends 3a and 3b of the coil wire constitute the terminals of the coil 2.

Un circuit d'alimentation 5 de cette bobine comprend une capacité 6, qui est montée en parallèle sur les bornes 3a et 3b de la bobine. La capacité 6 est reliée à une source de tension 7 par l'intermédiaire de moyens interrupteurs 8.A supply circuit 5 for this coil comprises a capacitor 6, which is mounted in parallel on the terminals 3a and 3b of the coil. The capacitor 6 is connected to a voltage source 7 by means of switch means 8.

Ces moyens interrupteurs permettent de connecter et déconnecter à volonté la source de tension 7 et le circuit électrique constitué par la capacité 6 et la bobine 2.These switching means make it possible to connect and disconnect at will the voltage source 7 and the electrical circuit constituted by the capacitor 6 and the coil 2.

Un mode particulier de réalisation de ces moyens sera décrit par la suite.A particular embodiment of these means will be described later.

Le fonctionnement de ce dispositif sera décrit maintenant en référence à la figure 2 qui représente le courant I circulant dans la bobine 2 en fonction du temps t.The operation of this device will now be described with reference to FIG. 2 which represents the current I flowing in the coil 2 as a function of time t.

Tout d'abord les moyens interrupteurs 8 sont actionnés de façon à relier la source de tension 7 à la capacité 6. Celle ci se charge et le courant qui circule dans la bobine 2 croit jusqu'à une valeur maximale Imax qui est atteinte au bout du temps t1.First of all, the switching means 8 are actuated so as to connect the voltage source 7 to the capacitor 6. This charges and the current flowing in the coil 2 increases to a maximum value Imax which is reached at the end of time t1.

A ce moment les moyens interrupteurs 8 sont actionnés de façon à déconnecter la source de tension de la capacité.At this time the switch means 8 are actuated so as to disconnect the voltage source from the capacitor.

Le circuit constitué par la capacité 6 et la bobine 2 devient alors un circuit oscillant, le courant qui circule dans la bobine est sinusoidal d'amplitude amortie.The circuit constituted by the capacitor 6 and the coil 2 then becomes an oscillating circuit, the current which circulates in the coil is sinusoidal of damped amplitude.

La forme du courant obtenu permet de générer dans la bobine un champ magnétique de forme analogue et qui se rapproche de la signature magnétique d'un véhicule réel.The shape of the current obtained makes it possible to generate in the coil a magnetic field of similar shape and which approaches the magnetic signature of a real vehicle.

Au bout d'un temps t2 il est possible de connecter une nouvelle fois la capacité à la source de tension 7 pendant une nouvelle durée t1, puis d'ouvrir à nouveau le circuit.At the end of a time t2 it is possible to connect the capacitor again to the voltage source 7 for a new duration t1, then to open the circuit again.

La courbe de courant obtenue au cours de ce deuxième cycle est représentée sur la figure 2 en traits interrompus.The current curve obtained during this second cycle is shown in Figure 2 in broken lines.

Il est possible de jouer sur les valeurs de la capacité 6, de l'inductance et de la résistance de la bobine 2 ainsi que sur les temps t1 et t2 pour modifier la forme du champ magnétique engendré par le dispositif.It is possible to play on the values of the capacitance 6, the inductance and the resistance of the coil 2 as well as on the times t1 and t2 to modify the shape of the magnetic field generated by the device.

A titre d'exemple, on choisira de préférence une bobine telle que son rapport R/2L (où R est la résistance de la bobine et L son inductance) est compris entre 8 et 12. De telles valeurs permettent d'obtenir des bobines dont la constante de temps d'amortissement est comprise entre 80 et 120 millisecondes.As an example, a coil will preferably be chosen such that its ratio R / 2L (where R is the resistance of the coil and L its inductance) is between 8 and 12. Such values make it possible to obtain coils whose the damping time constant is between 80 and 120 milliseconds.

On choisira alors une capacité C telle que la fréquence d'oscillation libre du circuit capacité-bobine soit comprise entre 10 et 20 Hz. Une capacité de l'ordre de 0.01 Farad donne satisfaction pour une bobine dont l'inductance est de l'ordre de 50 milli Henry.We will then choose a capacitance C such that the free oscillation frequency of the capacitance-coil circuit is between 10 and 20 Hz. A capacitance of the order of 0.01 Farad gives satisfaction for a coil whose inductance is of the order 50 milli Henry.

Avec de telles valeurs, la durée tl choisie sera de l'ordre de 200 millisecondes, soit approximativement deux constantes de temps d'amortissement de la bobine. On laissera osciller ensuite le circuit pendant 5 à 10 périodes du circuit oscillant capacité-bobine (soit entre 0.5 et 1 seconde pour une fréquence de 10 hz).With such values, the duration tl chosen will be of the order of 200 milliseconds, or approximately two damping time constants of the coil. The circuit will then be left to oscillate for 5 to 10 periods of the capacity-coil oscillating circuit (i.e. between 0.5 and 1 second for a frequency of 10 Hz).

Le dispositif ainsi décrit consomme moins d'énergie que les dispositifs connus.The device thus described consumes less energy than the known devices.

En effet, il prélève sur la source de tension 7 la puissance nécessaire à établir le courant dans la bobine pendant t1. Ensuite, jusqu'à t2, la puissance qu'il prélève sur la source de tension est nulle.Indeed, it takes from the voltage source 7 the power necessary to establish the current in the coil during t1. Then, until t2, the power it takes from the voltage source is zero.

Au contraire, les systèmes selon l'état de la technique prélèvent de la puissance sur la source de tension de façon continue.On the contrary, the systems according to the state of the art draw power from the voltage source continuously.

A puissance dissipée dans la self égale, l'économie de puissance obtenue avec le dispositif selon l'invention peut être supérieure ou égale à 50%. Elle dépendra d'une façon générale des caractéristiques de la bobine. Avec les valeurs données précédemment à titre d'exemple, l'économie de puissance est de l'ordre de 70%.For a power dissipated in the same inductor, the power saving obtained with the device according to the invention can be greater than or equal to 50%. It will depend in a way general characteristics of the coil. With the values given previously by way of example, the power saving is of the order of 70%.

La figure 3 représente un schéma de moyens interrupteurs 8 pouvant être utilisés dans le dispositif selon l'invention. La bobine 2 est représentée schématiquement sur cette figure.FIG. 3 represents a diagram of switch means 8 which can be used in the device according to the invention. The coil 2 is shown schematically in this figure.

Ces moyens interrupteurs 8 comprennent un transistor 11 du type MOS ("Metal Oxyde Semiconductor") dont le Drain (D) est connecté à la capacité 6 et la Source (S) est reliée à la source de tension 7.These switching means 8 comprise a transistor 11 of the MOS ("Metal Oxide Semiconductor") type, the Drain (D) of which is connected to the capacitor 6 and the Source (S) of which is connected to the voltage source 7.

La base (Gate G) du transistor 11 reçoit des signaux fournis par un circuit électronique de commande 12.The base (Gate G) of the transistor 11 receives signals supplied by an electronic control circuit 12.

Ce dernier est alimenté par la source de tension 7 et il délivre un signal constitué par des créneaux de tension de largeur égale à t1 et de période égale à t2.The latter is supplied by the voltage source 7 and it delivers a signal consisting of voltage slots of width equal to t1 and of period equal to t2.

Le circuit de commande 12 comporte également un interrupteur (non représenté ici) et permettant la mise en marche ou l'arrêt du dispositif.The control circuit 12 also includes a switch (not shown here) and allowing the device to be started or stopped.

Un tel circuit de commande qui génère des créneaux est bien connu de l'homme du métier et il ne sera pas décrit ici plus en détail.Such a control circuit which generates slots is well known to those skilled in the art and will not be described here in more detail.

L'amplitude des créneaux de tension sera adaptée aux caractéristiques du transistor MOS 11, elle est habituellement de l'ordre de 5 volts.The amplitude of the voltage slots will be adapted to the characteristics of the MOS transistor 11, it is usually of the order of 5 volts.

Une résistance 13 relie la base G à la source de tension 7, elle a pour fonction d'adapter l'impédance du circuit de commande 12 avec la Gate du MOS.A resistor 13 connects the base G to the voltage source 7, its function is to adapt the impedance of the control circuit 12 with the gate of the MOS.

Le fonctionnement de ces moyens interrupteurs est le suivant: lorsque le circuit de commande 12 est mis en marche, il délivre un signal comprenant des créneaux de durée t1 qui se succèdent avec une période t2.The operation of these switching means is as follows: when the control circuit 12 is started, it delivers a signal comprising slots of duration t1 which follow one another with a period t2.

Le front montant du premier créneau, appliqué à la base G du transistor 11, permet le passage du courant de la Source S vers le Drain D. Les moyens interrupteurs 8 assurent alors la connexion de la capacité 6 à la source de tension 7. La capacité 6 est alors chargée par la source de tension 7 comme cela a été décrit précédemment.The rising edge of the first slot, applied to the base G of the transistor 11, allows the passage of current from the Source S to the Drain D. The switch means 8 then ensure the connection of the capacitor 6 to the voltage source 7. The capacity 6 is then charged by the voltage source 7 as described above.

A l'issue du temps tl, la base G du transistor 11 reçoit le front descendant du premier créneau fourni par le circuit de commande 12.At the end of time tl, the base G of the transistor 11 receives the falling edge of the first slot provided by the control circuit 12.

Ce front descendant rend le transistor 11 isolant, les moyens interrupteurs 8 assurent ainsi la deconnexion de la capacité 6 et de la source de tension 7. La capacité 6 se décharge alors dans la bobine 2 et constitue avec cette dernière un circuit oscillant comme cela a été décrit précédemment.This falling edge makes the transistor 11 insulating, the switching means 8 thus ensure the disconnection of the capacitor 6 and of the voltage source 7. The capacitor 6 then discharges into the coil 2 and constitutes with the latter an oscillating circuit as this has was previously described.

A l'issue du temps t2, les moyens de commande appliquent au transistor 11 un deuxième créneau de durée t1. Ce qui entraîne une nouvelle connexion suivie d'une deconnexion.At the end of time t2, the control means apply to transistor 11 a second time slot of duration t1. This results in a new connection followed by a disconnection.

D'autres moyens interrupteurs 8 pourraient être envisagés, par exemple un relais statique ou un relais électromécanique.Other switch means 8 could be envisaged, for example a static relay or an electromechanical relay.

La figure 4 représente une variante de réalisation du dispositif selon l'invention.FIG. 4 represents an alternative embodiment of the device according to the invention.

Il sera avantageux pour des valeurs de capacités relativement fortes d'utiliser des capacités électrochimiques. Ces dernières sont polarisées et ne peuvent donc pas travailler à la fois pour des alternances positives et négatives du courant circulant dans la bobine.It will be advantageous for relatively high capacity values to use electrochemical capacities. These are polarized and therefore cannot work for both positive and negative half-waves of the current flowing in the coil.

Dans la variante proposée la capacité 6 est remplacée par deux capacités électrochimiques 6a et 6b qui sont montées en série et reliées l'une à l'autre par une de leurs électrodes de même signe, ici les électrodes négative 9a et 9b.In the proposed variant, the capacity 6 is replaced by two electrochemical capacities 6a and 6b which are connected in series and connected to one another by one of their electrodes of the same sign, here the negative electrodes 9a and 9b.

Chaque capacité est court circuitée par une diode 10a, 10b qui permet un passage de courant dans un sens inverse de celui de la capacité considérée.Each capacitor is short-circuited by a diode 10a, 10b which allows current to flow in the opposite direction to that of the capacitor considered.

La courbe de courant circulant dans la bobine 2 qui est obtenue avec cette variante est du même type que celle décrite précédemment en référence à la figure 2.The current curve flowing in the coil 2 which is obtained with this variant is of the same type as that described previously with reference to FIG. 2.

On notera simplement que lors de la décharge des capacités 6a, 6b, les parties négatives des oscillations amorties sont fournies par la décharge d'une capacité alors que les parties positives sont fournies par la décharge de l'autre capacité.It will simply be noted that during the discharge of the capacities 6a, 6b, the negative parts of the damped oscillations are provided by the discharge of one capacity while the positive parts are provided by the discharge of the other capacity.

Lors de la connexion des capacités à la source de tension 7, cette dernière chargera la capacité 6b. La capacité 6a se chargera lors de la première oscillation du circuit oscillant constitué par les capacités et la bobine.When connecting the capacitors to the voltage source 7, the latter will charge the capacitor 6b. The capacitor 6a will be charged during the first oscillation of the oscillating circuit constituted by the capacitors and the coil.

La figure 5 représente un deuxième mode de réalisation du dispositif selon l'invention.FIG. 5 represents a second embodiment of the device according to the invention.

Dans ce mode de réalisation, la source de tension est constituée par un condensateur 14. Les moyens interrupteurs sont des moyens commutateurs 15, c'est à dire des moyens qui assurent d'une part la connexion et la deconnexion de la capacité 6 à la source de tension constituée par le condensateur 14, et d'autre part le raccordement du condensateur 14 à une alimentation de charge 16, lorsque la capacité 6 est déconnectée.In this embodiment, the voltage source consists of a capacitor 14. The switching means are switching means 15, that is to say means which ensure on the one hand the connection and disconnection of the capacitor 6 to the voltage source constituted by the capacitor 14, and on the other hand the connection of the capacitor 14 to a load supply 16, when the capacity 6 is disconnected.

Un mode particulier de réalisation des moyens commutateurs 15 sera décrit par la suite.A particular embodiment of the switching means 15 will be described below.

Le fonctionnement de ce deuxième mode de réalisation va être décrit en référence à la figure 6.The operation of this second embodiment will be described with reference to FIG. 6.

Dans un premier temps le commutateur 15 relie le condensateur 14 à l'alimentation de charge 16 (qui est par exemple constituée par une batterie). La courbe supérieure 17 représente les variations du courant de charge Ic du condensateur 14 au cours du temps. Ce courant atteint son maximum Icmax au bout du temps t'0.Initially the switch 15 connects the capacitor 14 to the load supply 16 (which is for example constituted by a battery). The upper curve 17 represents the variations in the charging current Ic of the capacitor 14 over time. This current reaches its maximum Icmax at the end of time t'0.

A ce moment les moyens commutateurs 15 relient le condensateur 14 à la capacité 6, tout en deconnectant dans le même temps le condensateur 14 de l'alimentation de charge 16.At this moment the switching means 15 connect the capacitor 14 to the capacitor 6, while at the same time disconnecting the capacitor 14 from the load supply 16.

Le condensateur 14 assure alors la charge de la capacité 6 pendant la durée t'1-t'0. Le courant qui circule dans la bobine 2 croit jusqu'à une valeur maximale Imax qui est atteinte au bout du temps t'1-t'0 (voir la courbe inférieure 18). Le condensateur 14 se décharge totalement dans la capacité 6 et la bobine 2.The capacitor 14 then charges the capacitor 6 for the duration t'1-t'0. The current flowing in the coil 2 increases to a maximum value Imax which is reached at the end of time t'1-t'0 (see lower curve 18). The capacitor 14 discharges completely in the capacitor 6 and the coil 2.

A l'instant t'1 les moyens commutateurs 15 sont actionnés de façon à déconnecter le condensateur 14 de la capacité 6.At instant t'1 the switching means 15 are actuated so as to disconnect the capacitor 14 from the capacitor 6.

Le circuit constitué par la capacité 6 et la bobine 2 devient alors un circuit oscillant, le courant qui circule dans la bobine est sinusoidal d'amplitude amortie.The circuit constituted by the capacitor 6 and the coil 2 then becomes an oscillating circuit, the current which circulates in the coil is sinusoidal of damped amplitude.

La forme du courant obtenu permet de générer dans la bobine un champ magnétique de forme analogue et qui se rapproche de la signature magnétique d'un véhicule réel.The shape of the current obtained makes it possible to generate in the coil a magnetic field of similar shape and which approaches the magnetic signature of a real vehicle.

Pendant ce temps le condensateur 14 se trouve de nouveau relié à l'alimentation 16 et il se recharge (voir courbe 17).During this time the capacitor 14 is again connected to the power supply 16 and it recharges (see curve 17).

La durée de charge sera choisie telle qu'il soit possible de reconnecter le condensateur 14 à la bobine 2 à l'issue d'un temps t'2-t'1. Cette connexion sera effectuée pendant une nouvelle durée t'1-t'0 nécessaire à l'établissement du courant dans la bobine, le condensateur 14 est ensuite à nouveau déconnecté de la capacité 6.The charging time will be chosen such that it is possible to reconnect the capacitor 14 to the coil 2 after a time t'2-t'1. This connection will be made for a new period t'1-t'0 necessary for establishing the current in the coil, the capacitor 14 is then again disconnected from the capacitor 6.

Les courbes de courant obtenues au cours du deuxième cycle sont représentées sur la figure 7 à titre indicatif en traits interrompus.The current curves obtained during the second cycle are shown in FIG. 7 by way of indication in dashed lines.

Il est possible, comme dans le premier mode de réalisation précédemment décrit, de jouer sur les valeurs de la capacité 6, de l'inductance et de la résistance de la bobine 2 ainsi que sur les temps t'1 et t'2 pour modifier la forme du champ magnétique engendré par le dispositif.It is possible, as in the first embodiment described above, to play on the values of the capacitance 6, the inductance and the resistance of the coil 2 as well as on the times t'1 and t'2 to modify the shape of the magnetic field generated by the device.

Le condensateur 14 aura dans tous les cas une capacité C1 supérieure à celle C de la capacité 6.The capacitor 14 will in all cases have a capacity C1 greater than that C of the capacity 6.

La valeur de C1 sera déterminée en fonction de l'inductance L et de la résistance R de la bobine 2 de telle sorte que le circuit constitué par le condensateur 14 et la bobine 2 soit apériodique critique ce qui signifie que C1 sera tel que LC1 soit égal à (2L/R)2.The value of C1 will be determined as a function of the inductance L and the resistance R of the coil 2 so that the circuit formed by the capacitor 14 and coil 2 is critical aperiodic which means that C1 will be such that LC1 is equal to (2L / R) 2 .

A titre d'exemple, avec les valeurs définies précédemment, soit une bobine 2 d'inductance L de l'ordre de 50 milli Henry et une capacité 6 de l'ordre de 0.01 Farad, on pourra choisir un condensateur 14 dont la capacité C1 est de l'ordre de 0.1 Farad.By way of example, with the values defined above, ie a coil 2 with inductance L of the order of 50 milli Henry and a capacity 6 of the order of 0.01 Farad, we can choose a capacitor 14 whose capacity C1 is around 0.1 Farad.

Avec de telles valeurs la durée de charge t'1-t'0 est toujours de l'ordre de 200 millisecondes soit approximativement deux constantes de temps d'amortissement de la bobine. Le circuit oscille pendant 5 à 10 périodes du circuit oscillant capacité-bobine (soit entre 0.5 et 1 seconde pour une fréquence de 10 hz).With such values the charge time t'1-t'0 is always of the order of 200 milliseconds, ie approximately two damping time constants of the coil. The circuit oscillates for 5 to 10 periods of the capacity-coil oscillating circuit (i.e. between 0.5 and 1 second for a frequency of 10 Hz).

Cette durée d'oscillation est suffisante pour permettre la recharge du condensateur 14 par l'alimentation de charge 16.This oscillation time is sufficient to allow recharging of the capacitor 14 by the load supply 16.

Le dispositif selon ce deuxième mode de réalisation de l'invention consomme moins d'énergie que les dispositifs connus.The device according to this second embodiment of the invention consumes less energy than the known devices.

Néanmoins il consomme plus d'énergie que le dispositif selon le premier mode de réalisation, cela principalement en raison des pertes occasionnées lors de la décharge du condensateur 14 dans la capacité 6.Nevertheless, it consumes more energy than the device according to the first embodiment, this mainly due to the losses caused during the discharge of the capacitor 14 in the capacitor 6.

A puissance dissipée dans la self égale, on peut cependant évaluer l'économie de puissance obtenue avec ce mode de réalisation à 50% par rapport à un dispositif selon l'état de la technique.With power dissipated in the same inductor, it is however possible to evaluate the power saving obtained with this embodiment at 50% compared to a device according to the state of the art.

Le principal avantage de ce mode de réalisation par rapport au précédent est qu'il permet de limiter la valeur du courant maximal de décharge de la batterie du véhicule.The main advantage of this embodiment compared to the previous one is that it makes it possible to limit the value of the maximum discharge current of the vehicle battery.

En effet dans le premier mode de réalisation, la batterie constituait la source de tension 7 raccordée à la capacité 6, elle voyait un courant de l'ordre de 20 Ampères.Indeed in the first embodiment, the battery constituted the voltage source 7 connected to the capacitor 6, it saw a current of the order of 20 amperes.

Dans le deuxième mode de réalisation de l'invention, la batterie constitue l'alimentation de charge 16. Elle est alors connectée au condensateur 14 pendant une durée supérieure (de l'ordre de 100%) ce qui permet de limiter l'intensité débitée par la batterie à 10 Ampères.In the second embodiment of the invention, the battery constitutes the charge supply 16. It is then connected to the capacitor 14 for a longer period (of the order of 100%) which makes it possible to limit the intensity delivered by the 10 Amp battery.

Le courant de décharge de la batterie étant limité, la durée de vie de cette dernière se trouve augmentée et la fiabilité du dispositif également.The discharge current of the battery being limited, the lifespan of the latter is increased and the reliability of the device also.

La figure 7a représente un exemple de moyens commutateurs 15 utilisables dans ce deuxième mode de réalisation.FIG. 7a represents an example of switching means 15 usable in this second embodiment.

Ces moyens commutateurs comprennent deux transistors de type MOS 20 et 21 dont les bases G1 et G2 respectives reçoivent chacune un signal de commande différent fourni par un générateur de commandes 22.These switching means comprise two MOS type transistors 20 and 21, the respective bases G1 and G2 each of which receive a different control signal supplied by a command generator 22.

Le générateur de commandes 22 comporte également un interrupteur (non représenté) destiné à permettre la mise en marche et l'arrêt du dispositif.The command generator 22 also includes a switch (not shown) intended to enable the device to be started and stopped.

Le transistor 20 reçoit un signal S1 et le transistor 21 un signal S2.The transistor 20 receives a signal S1 and the transistor 21 a signal S2.

Ces signaux sont constitués par une succession de créneaux particuliers comme cela sera décrit par la suite.These signals are constituted by a succession of specific slots as will be described later.

Le générateur de commandes 22 est alimenté en énergie par l'alimentation de charge 16 (constituée par exemple par une batterie du véhicule). Des résistances 23 et 24 sont disposées entre les bases G1 et G2 des transistors 20 et 21 et l'alimentation de charge 16. Elles ont pour fonction d'adapter l'impédance du générateur de commande 22 avec les bases des transistors.The command generator 22 is supplied with energy by the load supply 16 (constituted for example by a vehicle battery). Resistors 23 and 24 are arranged between the bases G1 and G2 of the transistors 20 and 21 and the load supply 16. Their function is to adapt the impedance of the control generator 22 with the bases of the transistors.

Le transistor 20 est destiné à assurer la connexion du condensateur 14 à l'alimentation de charge, le transistor 21 permet de raccorder le condensateur 14 à la bobine 2 (représentée schématiquement).The transistor 20 is intended to ensure the connection of the capacitor 14 to the load supply, the transistor 21 makes it possible to connect the capacitor 14 to the coil 2 (shown diagrammatically).

La figure 7b montre les signaux S1 et S2 qui sont appliqués par le générateur de commandes 22 aux transistors 20 et 21.FIG. 7b shows the signals S1 and S2 which are applied by the command generator 22 to the transistors 20 and 21.

Le signal S1 (courbe du haut) est constitué par une série de créneaux de largeur t'0, le signal S2 (courbe du bas) par une série de créneaux de largeur t'1-t'0. Les deux signaux ont une même période égale à t'1.The signal S1 (top curve) consists of a series of slots of width t'0, the signal S2 (bottom curve) of a series of slots of width t'1-t'0. The two signals have the same period equal to t'1.

L'amplitude des créneaux de tension est adaptée aux caractéristiques des transistors MOS, elle est habituellement de l'ordre de 5 volts.The amplitude of the voltage slots is adapted to the characteristics of the MOS transistors, it is usually of the order of 5 volts.

Ainsi lorsque la base G1 du transistor 20 reçoit le front montant du premier créneau du signal S1, le transistor 20 réalise la connexion du condensateur 14 et de l'alimentation de charge 16. Cette connexion est maintenue pendant la durée t'0 qui permet la charge du condensateur 14 (voir figure 6).Thus when the base G1 of transistor 20 receives the rising edge of the first slot of signal S1, transistor 20 makes the connection of capacitor 14 and of load power 16. This connection is maintained for the duration t'0 which allows the charging of the capacitor 14 (see FIG. 6).

Pendant la même période, le transistor 21 ne reçoit aucun signal à sa base G2 et isole donc le condensateur 14 de la bobine 2.During the same period, the transistor 21 receives no signal at its base G2 and therefore isolates the capacitor 14 from the coil 2.

Au bout du temps t'0, le transistor 20 devient isolant tandis que le transistor 21 reçoit le front montant du premier créneau du signal S2. Le transistor 21 réalise alors la connexion du condensateur 14 à la bobine 2 et cela pendant le temps t'1-t'0,temps nécessaire à l'établissement du courant dans la bobine 2.At the end of time t'0, the transistor 20 becomes insulating while the transistor 21 receives the rising edge of the first slot of the signal S2. The transistor 21 then makes the connection of the capacitor 14 to the coil 2 and this for the time t'1-t'0, time necessary for the establishment of the current in the coil 2.

A l'instant t'1, le transistor 21 redevient isolant, permettant au régime sinusoïdal amorti de s'établir dans le circuit constitué par la capacité 6 et la bobine 2.At instant t'1, the transistor 21 becomes insulating again, allowing the damped sinusoidal regime to be established in the circuit constituted by the capacitor 6 and the coil 2.

Dans le même temps le signal S1 a commandé la connexion du condensateur 14 et de l'alimentation de charge 16, permettant ainsi la recharge de celui-ci.At the same time, the signal S1 has commanded the connection of the capacitor 14 and the load supply 16, thus allowing the latter to be recharged.

Le cycle de commutation peut se reproduire ainsi indéfiniment.The switching cycle can be repeated indefinitely.

D'autres moyens commutateurs 15 pourraient être envisagés, par exemple utilisant des relais statiques ou des relais électromécaniques.Other switching means 15 could be envisaged, for example using static relays or electromechanical relays.

Claims (5)

  1. A demining device (1), intended to ignite a magnetic influence mine from a distance and comprising a magnetic-field-generating coil (2) and its electrical supply circuit (5), this device being characterized in that the supply circuit comprises a capacitance (6) mounted in parallel on the terminals (3a, 3b) of the coil (2) and circuit breaking means (8, 15) enabling this capacitance (6) to be connected to and disconnected from a voltage source (7, 14), the circuit breaking means (8, 15) periodically activating a sequence comprising a connection for a first time interval tl intended to enable a current (Imax) to be established in the coil, connection followed by a disconnection for a second time interval t2 during which the circuit formed by the capacitance (6) and the coil (2) is a damped oscillating circuit.
  2. A demining device according to Claim 1, characterized in that the circuit breaking means (8) comprise a transistor (11) whose drain (D) is connected to the capacitance (6) and the source (S) is connected to the voltage source (7), the transistor gate (G) receiving power pulses supplied by an electrical control circuit (12).
  3. A demining device according to one of Claims 1 or 2, characterized in that the capacitance is formed of two electrochemical capacitances (6a, 6b) mounted in series and connected to one another by one of their electrodes of the same sign, each capacitance being short-circuited by a diode (10a, 10b) enabling a current to pass in the opposite direction to that of the capacitance in question.
  4. A demining device according to one of Claims 1 to 3, characterized in that the voltage source comprises a capacitor (14) and in that the circuit breaking means are commutator means (15) which connect the capacitor (14) to a power supply (16) when the capacitance (6) is disconnected.
  5. A demining device according to Claim 4, characterized in that the commutator means (15) comprise two transistors (20, 21) whose respective terminals each receive a different control signal supplied by a control generator (22), a first transistor (21) being intended to ensure the periodic connection and disconnection of the capacitance (6) from the capacitor (14), a second transistor (20) being intended to ensure the periodic connection and disconnection of the capacitor (14) to the power supply (16).
EP94904680A 1993-02-01 1994-01-14 Mine clearance device Expired - Lifetime EP0638160B1 (en)

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FR9301039A FR2701105B1 (en) 1993-02-01 1993-02-01 Demining device.
FR9301039 1993-02-01
PCT/FR1994/000050 WO1994018520A1 (en) 1993-02-01 1994-01-14 Mine clearance device

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EP0638160A1 EP0638160A1 (en) 1995-02-15
EP0638160B1 true EP0638160B1 (en) 1997-10-15

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DE (1) DE69406220T2 (en)
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Also Published As

Publication number Publication date
IL108485A (en) 1998-12-27
WO1994018520A1 (en) 1994-08-18
FR2701105B1 (en) 1995-04-14
DE69406220T2 (en) 1998-04-16
FR2701105A1 (en) 1994-08-05
ATE159342T1 (en) 1997-11-15
US5458063A (en) 1995-10-17
ES2110218T3 (en) 1998-02-01
GR3025869T3 (en) 1998-04-30
DK0638160T3 (en) 1998-05-25
EP0638160A1 (en) 1995-02-15
DE69406220D1 (en) 1997-11-20

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