Power amplification device

Abstract

The present invention relates to a power amplification device capable of being powered by a single input voltage and comprising a switching module comprising a first discharge electrode and a second discharge electrode. The power amplification device comprises a triggering module configured to convert the input voltage into a first supply voltage and a second supply voltage, detect an activation event, generate an activation signal from the first supply voltage when an activation event has been detected, generate a pulse command from the second supply voltage when an activation signal has been generated, and transmit the generated pulse control to the triggering means of the switching module so that it triggers the formation of an electric arc between the first discharge electrode and the second discharge electrode.

Claims

1. Power amplification device capable of being powered by one single input voltage and comprising a switching module, said switching module comprising a first discharge electrode and a second discharge electrode, arranged opposite one another at a predetermined set distance defining a space for generating an electric arc, and a triggering means located near said space and being configured to trigger the formation of said electric arc in said space, said power amplification device comprising a triggering module configured to: convert the input voltage into a first supply voltage and into a second supply voltage, detect an activation event, generate, from the first supply voltage, an activation signal when an activation event has been detected, generate, from the second supply voltage, a pulse command when an activation signal has been generated, and transmit the pulse command generated to the triggering means of the switching module, so that the triggering means triggers the formation of an electric arc between the first discharge electrode and the second discharge electrode.

2. Power amplification device according to claim 1, wherein the triggering module is configured to compare the value of the input voltage with a predetermined threshold value and to generate the activation signal when the value of the input voltage is greater than or equal to the predetermined threshold value.

3. Power amplification device according to claim 1, wherein the triggering module comprises a timer and is configured to generate the activation signal periodically relying on said timer.

4. Power amplification device according to claim 1, wherein the value of the first voltage is between 1 and 10V.

5. Power amplification device according to claim 1, wherein the activation signal is presented in the form of a voltage step of which the amplitude is equal to the value of the first voltage.

6. Power amplification device according to claim 1, wherein the value of the second voltage is around several hundred Volts.

7. Power amplification device according to claim 1, wherein the pulse command is presented in the form of a voltage pulse signal of which the duration is between 0.5 and 10 s.

8. Power amplification device according to claim 7, wherein the voltage pulse signal reaches a maximum value of around 20 kV, making it possible for the triggering means to trigger the formation of the electric arc between the first discharge electrode and the second discharge electrode.

9. Power amplification system comprising a power amplification device according to claim 8 and a current generator delivering a voltage of between 5 and 40 kV at the input of said power amplification device.

10. Method for generating an electric arc between a first discharge electrode and a second discharge electrode, arranged opposite one another at a predetermined set distance defining a space for generating an electric arc, the generation of said electric arc being triggered by a triggering means located near said space, said method, implemented by a power amplification device powered by an input voltage, comprising the steps of: converting the input voltage into a first supply voltage and into a second supply voltage, detecting an activation event, generating, from the first supply voltage, an activation signal when an activation event has been detected, generating, from the second supply voltage, a pulse command when an activation signal has been generated, and transmitting said pulse command generated by the triggering means, so that the triggering means triggers the formation of an electric arc between the first discharge electrode and the second discharge electrode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 (already outlined) schematically illustrates a triggered power amplification device of the prior art.

(2) FIG. 2 schematically illustrates an embodiment of a power amplification system according to the invention.

(3) FIG. 3 schematically illustrates an embodiment of the method according to the invention.

(4) FIG. 4 is an example of an input voltage signal of the power amplification device of FIG. 2.

(5) FIG. 5 is an example of an activation signal generated by the detection module and of the power amplification device of FIG. 2.

(6) FIG. 6 is an example of a pulse command generated by the pulse generator of the power amplification device of FIG. 2.

(7) FIG. 7 is an example of an output current signal of the power amplification device of FIG. 2.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(8) The power amplification device according to the invention is a switching device of the close switch type, comprising two separate electrodes, called discharge electrodes, separated by a dielectric (gas, vapour, vacuum, etc.), between which is formed an electric arc when the potential difference between the electrodes is greater than a threshold value. In such a high voltage device, this threshold value is greater than a few kV (kilovolts), and the operating voltage of the device (voltage applied to the power amplification device, i.e. the potential difference between the electrodes thereof), may go up to 1 MV. Such a power amplification device makes it possible to transfer a quantity of electrical charges going from a few millicoulombs to several hundred coulombs, corresponding to an electrical current passing through the power amplification device with an intensity of between 1 kA and 1 MA. Associated with a current generator, and in particular with one or more condensers capable of accumulating the quantities of the abovementioned electrical charges, this device may be used for various applications. The power amplification device according to the invention is a self-triggered power amplification device which is powered only by one single current generator. As an example, the device according to the invention may be used to sequentially power a bench for testing highly pressurised materials or any other charge, or in a borehole with a seismic purpose, for example to stimulate the production of petroleum. Each condenser discharge and charge transfer operation by the power amplification device, of the electrical charges initially accumulated in the condenser, is called a shot.

(9) In FIG. 2, an embodiment of a system 9 according to the invention has been represented. This system 9 comprises a power amplification device 10 and a current generator 7 delivering one single input voltage Ue to the device 10 via a high voltage supply cable 8.

(10) The device 10 comprises a switching module 100 and a triggering module 200.

(11) The switching module 100 comprises a first discharge electrode 110 and a second discharge electrode 120 arranged opposite one another at a predetermined set distance D and defining a space E for generating an electric arc A2 from the input voltage Ue. To do this, the current generator 7 comprises one or more condensers which are charged over time so as to deliver an increasing voltage Ue which could reach several kV, for example between 5 and 40 kV, until the formation of the electric arc A2 between the first discharge electrode 110 and a second discharge electrode 120 as will be explained below.

(12) The switching module 100 then comprises a triggering means located near the space E and which is configured to trigger the formation of an electric arc A2 in said space E. In this example, this triggering means is presented in the form of a third electrode, called triggering electrode 130. This triggering electrode 130 makes it possible to create an ionised air channel A1 in the space E, facilitating the formation of the electric arc A2 (called main electric arc) between the first discharge electrode 110 and the second discharge electrode 120, thus allowing the current to pass.

(13) In a known manner, during a shot, the electrical charges are propagated from the connecting end of the first discharge electrode 110 towards the end of the second discharge electrode 120 through the space E.

(14) The first discharge electrode 110 and the second discharge electrode 120 are preferably of a generally hollow and cylindrical shape, circularly-symmetrical. In a known manner the first discharge electrode 110 and the second discharge electrode 120 are aligned end-to-end, i.e. arranged such that the respective longitudinal axes thereof (not represented) coincide and that they have axial ends (not represented), called closing ends, at a predetermined set distance D from one another, for example between around 1 and 15 mm from one another, and opposite in the axial direction (direction of the axes of symmetry).

(15) The electric arc A2 occurs between these axial closing ends, of which the opposite annular end faces are substantially flat (in the transverse planes). The axial ends opposite the electrodes, called connecting ends, are each connected to a connector (not represented) for the purpose of integrating the power amplification device in an electrical circuit. In particular, one of the connectors is used for the connection of the current generator 7 and the other is used for the connection of a charge, for example.

(16) The triggering module 200 is connected to the switching module 100 in order to control it. The triggering module 200 is configured to convert the input voltage Ue into a first supply voltage BT1 and into a second supply voltage BT2, to detect an activation event and to generate, from the first supply voltage BT1, an activation signal S.sub.act when an activation event has been detected.

(17) To this end, in the preferred embodiment illustrated in FIG. 2, the triggering module 200 comprises a voltage converter 210, a detection sub-module 220 and a pulse generator 230.

(18) The voltage converter 210 is configured to convert the input voltage Ue provided by the external current generator 7 into a first supply voltage BT1 and into a second supply voltage BT2. The first supply voltage BT1, preferably of around a few Volts (for example, 5V), makes it possible to power the detection sub-module 220 with electrical energy. The second supply voltage BT2, preferably of around a few hundred Volts (for example, 500V), makes it possible to power the pulse generator 230 with electrical energy.

(19) In a first embodiment, the detection sub-module 220 is configured to receive the input voltage Ue provided by the current generator 7, to compare the value of said input voltage Ue with a predetermined threshold value Uc and, when the value of the input voltage Ue is greater than or equal to the predetermined threshold value Uc, to generate an activation signal S.sub.act from the first supply voltage BT1 and to send said activation signal S.sub.act to the pulse generator 230. In this case, the detection of the exceeding of the predetermined threshold value Uc by the input voltage Ue constitutes the activation event. Preferably, in reference to FIG. 6, the delay T1 between the detection of the predetermined threshold value by the detection sub-module 220 and the start of the current transfer by the triggering electrode 130 is less than 100 s.

(20) In a second embodiment of the device, the detection sub-module 220 comprises a timer (not represented) and is configured to generate the activation signal S.sub.act periodically from said timer and to send said activation signal S.sub.act to the pulse generator 230. In this case, the activation event corresponds to the start of the periodic interval during which the activation signal S.sub.act is generated and sent. Such a timer being known per se, it will not be detailed further here.

(21) The activation signal S.sub.act may be a TTL (Transistor-Transistor Logic) signal known per se, corresponding to a voltage step of which the amplitude is equal to the first supply voltage BT1, for example 5V, as illustrated in FIG. 5.

(22) The pulse generator 230 is configured to receive an activation signal S.sub.act from the detection sub-module 220, to generate a pulse command C.sub.i from the second supply voltage BT2, consecutively to receiving said activation signal S.sub.act and to transmit said pulse command C.sub.i to the triggering electrode 130 in order to trigger the generation of an electric arc between the first discharge electrode 100 and the second discharge electrode 200.

(23) The invention will now be described in the implementation thereof in reference to FIGS. 3 to 7.

(24) In reference firstly to FIGS. 3 and 4, the current generator 7 generates in a step E0, a current which defines an input voltage Ue of the power amplification device 10. This input voltage Ue is preferably between 5 and 40 kV. This input voltage Ue, generated by the charge of the condenser(s) of the current generator 7, increases over time until reaching a maximum value Umax for which an electric arc A2 is formed between the first electrode 110 and the second electrode 120 driving the discharge of the condensers of the current generator 7 and the drop of the input voltage Ue to zero.

(25) In a step E1, the converter 210 converts the input voltage Ue delivered by the current generator 7, on the one hand, into a first supply voltage BT1 of the detection sub-module 220 and, on the other hand, into a second supply voltage BT2 of the pulse generator 230. In this non-limiting example, the first supply voltage BT1 is of around 5V and the second supply voltage BT2 is of around 500V.

(26) Also in reference to FIGS. 3 and 4, in a first embodiment implementing the first embodiment of the device 10 presented above, the detection sub-module 220, which also receives the input voltage Ue, permanently compares, in a step E2A, the value of said input voltage Ue with a predetermined threshold value Uc, for example of 30 kV. When the value of the input voltage Ue reaches (i.e. equals) the predetermined threshold value Uc, the detection sub-module 220 generates, in a step E3, an activation signal S.sub.act from the first supply voltage BT1 and transmits it to the pulse generator 230 in a step E4. As illustrated in FIG. 5, this activation signal S.sub.act is presented in this example in the form of a voltage step of 5V, corresponding to the value of the first supply voltage BT1.

(27) In a second embodiment implementing the second embodiment of the device 10 presented above, the detection sub-module 220 detects the start of the periodic time interval generated by the timer in a step E2B and thus periodically generates the activation signal S.sub.act in a step E3, then transmits it to the pulse generator 230 in a step E4. It will be noted, that in the second embodiment using a timer, the voltage for which the electric arc is formed may be defined by adapting the charge time of the condensers such that it corresponds to the period of the timer.

(28) In reference to FIG. 6, when it receives this activation signal S.sub.act, the pulse generator 230 itself generates, in a step E5, a pulse command C.sub.i from the second supply voltage BT2 generated and provided by the converter 210. This pulse command is transmitted in a step E6 to the triggering electrode 130.

(29) In this example, the pulse command C.sub.i is presented in the form of a voltage pulse signal starting at the end of the delay T1, the start of this voltage peak being detected when the voltage exceeds a minimum threshold value. This minimum threshold value may be equal to 10% of the maximum voltage, that is, for example, a minimum threshold value of 0.1V. This delay T1 corresponds to the time elapsed between the detection of the threshold Uc and the generation of the triggering pulse C.sub.i. The pulse signal increases, for a delay T2 comprised in this example between 0.5 and 10 s after the start thereof, to a maximum value of 20 kV.

(30) During this increase of the voltage at the terminals of the triggering electrode 130, an ionised air channel A1 is created between the first discharge electrode 110 and the second discharge electrode 120. When the voltage reaches the predetermined threshold value or the end of the timer period, the main electric arc A2 is generated, in a step E7, between the first discharge electrode 110 and the second discharge electrode 120.

(31) The input voltage Ue thus instantaneously drops to zero, in the same way as the voltage value of the activation signal S.sub.act (end of the voltage step) and as the voltage value of the pulse command C.sub.i . In reference to FIG. 7, the formation of the electric arc A2 generates an oscillating output current I.sub.out of which the value may be between, in this example, 10 and 30 kA.

(32) The invention therefore makes it possible to trigger a shot by using a triggering electrode 130 without using an external voltage supply, the supply of the triggering generator 230 being achieved by the second voltage BT2 generated by the voltage converter 210. The triggered power amplification device 10 according to the invention therefore only requires one single external supply (current generator 7), which reduces the number of cables and makes it possible to easily use it in places that are difficult to access such as boreholes, while making it possible for a triggering of the shots at a constant threshold value, using the triggering electrode.

(33) It must be noted that the present invention is not limited to the examples described above, and it is likely to have numerous variants accessible to a person skilled in the art.