NL1019171C2 - High voltage pulse generator comprises at least one resonant charging connection, capacitor-spark bridge combination and transmission line transformer - Google Patents

Abstract

The high voltage pulse generator comprises at least one resonant charging connection, a capacitor-spark bridge combination (2a,2b) and a transmission line transformer (1). In operation, the charging connection charges the capacitor (4a,4b), which activates the spark-bridge (3a,3b), so that the voltage over the capacitor is high enough and therefore creates a spark-bridge voltage pulse conducted through the transmission line transformer. The transmission line transformer is composed of two or more transmission sections (1a,1b), each of which is provided with an input side and an output side. Each transmission section is separately coupled with a capacitor-spark bridge combination, so that the activation of a spark bridge of such a combination induces the activation of all spark-bridges of all capacitor-spark bridge combinations.

Description

Brief indication: High voltage pulse generator device.

DESCRIPTION

The invention relates to a high-voltage pulse generator device comprising at least a resonant charging circuit, a capacitor-spark gap combination, and a transmission line transformer, wherein in operation the charging circuit charges the capacitor, which ignites the spark gap as soon as the voltage is high enough across the capacitor and thus creates a spark bridge voltage pulse guided by the transmission line-transformer.

A high voltage pulse generator device according to the preamble as well as an application for this is disclosed, for example, in International Patent Application No. PCT / NL96 / 00463, published under No. WO97 / 18899. A high voltage pulse generator device is used herein for treating gases or liquids with pulsed corona discharges. In this case, pulses of a few tens of kV from the resonant charging circuit are converted via the spontaneously switching spark gantry into very fast rising pulses and applied to the transmission line transformer, in which a voltage multiplication can occur up to approximately four times the applied pulse of a few tens of kV . The output of the transmission line transformer is then connected to a load which is a corona discharge space in the aforementioned patent No. PCT / NL96 / 00463.

As a result of the voltage signals usual for such an application and for obtaining a relatively long service life, the spark gap has heavy-duty electrodes, so that it is complex and expensive in construction. In addition to the often limited service life of the spark gap, the use of a high-voltage pulse generator device according to the above-mentioned preamble is also limited by the maximum achievable pulsed power that can be passed through the transmission line transformer.

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It is an object of the present invention to provide a high-voltage pulse generator device according to the preamble, which allows a higher pulsed power through the transmission line transformer with a lower load on the spark gap, so that the high-voltage pulse generator device can also be used for industrial applications where such signals are desirable.

According to the invention, the high-voltage pulse generator device is to that end characterized in that the transmission-line transformer is composed of two or more transmission sections, each section being provided with an input side and output side and consisting of at least one transmission line. from at least one coaxial inner conductor with an inner conductor input terminal and an inner conductor output terminal and an outer conductor with an outer conductor input terminal and an outer conductor output terminal, each transmission section being individually coupled to a capacitor spark gap combination such that igniting a spark gap of a capacitor-spark gap combination initiates the ignition of all spark bridges of all capacitor-spark gap combinations.

This construction makes it possible to synchronize the spark gaps of the different transmission sections or lines, so that they collectively - after the first spark gage is triggered - deliver a voltage pulse which is guided through the transmission lines. Because each transmission section of the transmission line transformer is coupled to its own spark gap, which controls the relevant transmission section 25 separately, in this configuration each spark gap can be operated separately with less transmitted power, while synchronization through the thus formed Transmission line transformer signal pulses with higher power are conducted.

More specifically, a transmission section is composed of two or more transmission lines, with the respective inner conductor input terminals of the transmission lines 3 mutually and the respective outer input input terminals of the transmission lines mutually with each other connected.

In another embodiment according to the invention, a transmission section is composed of two or more transmission lines, the outer conductor input terminal of a transmission line being connected at the input side to the inner conductor input terminal of the next transmission line.

A highly functional synchronization of the individual transmission sections or lines by simultaneously igniting the different spark gaps can be achieved in that, according to the invention, the capacitor-spark bridge combination is composed of a series connection of a capacitor and spark bridge, wherein a the free end of the spark gap on the input side is connected to the inner conductor input terminal of a transmission section and that the outer conductor input terminal of the transmission section is connected to a free end of the capacitor of a subsequent capacitor-spark bridge combination of the next transmission section.

A specific embodiment, wherein the different transmission sections are c.g. lines are each driven by a separate spark gap 20 and wherein a voltage pulse applied across the spark gap or capacitor can be increased many times by the transmission line transformer, is characterized in that on the output side the outer conductor output terminal of a transmission section is connected to the inner conductor output terminal of the next transmission section.

Another specific embodiment where not so much the voltage pulse is multiplied by the transmission line transformer but where considerably higher pulse currents can be generated, is characterized according to the invention in that on the output side the respective inner conductor output terminals of the transmission sections mutually and the respective outer conductor - 4 output terminals of the transmission sections are mutually connected. This allows the use of the high-voltage pulse generator device according to the invention in applications where pulse signals with a relatively high current intensity are required.

In other specific embodiments where both a spark bridge voltage pulse led by the transmission line transformer can be increased to a higher voltage and current, this is characterized in that the transmission line transformer is composed of a plurality of paired coupled transmission sections such that the output side for each pair of the outer conductor output terminal of the first transmission section is connected to the inner conductor output terminal of the second transmission section, furthermore the outer conductor output terminals of the second transmission sections of each pair are interconnected and the inner conductor output terminals of the first transmission sections of 15 pairs each are connected to each other.

In a specific embodiment of the high-voltage pulse generator device according to the invention, it is characterized in that one or more transmission sections are provided with an envelope consisting of one or more kinds of magnetic material. This prevents the unwinding of disturbing wave signals via the outer conductors.

The invention further relates to a capacitor-spark bridge combination for use in a high-voltage pulse generator device according to the invention, comprising a capacitor which can be charged by a resonant charging circuit, and a spark bridge connected in series with the capacitor and consisting of at least a small distance first and second electrode spaced apart, thus forming a spark gap, the second electrode being connected on the input side to the inner conductor input terminal of a transmission section 30 of the transmission-line transformer of the high-voltage pulse generator device. According to the invention, the spark gap is provided with a third electrode, so that the ignition of the spark gap is more controllable.

A good control of the ignition moment of the spark gap can be achieved in that the combination is provided with an LCR-5 circuit, the coil L with the first electrode of the spark gap and the resistor R on the input side with the outer conductor input terminal of a transmission terminal. section of the transmission line transformer is connected and the third electrode is connected between the capacitor C and the resistor R with the LCR circuit.

The third electrode can herein be placed in the spark gap between the first and second electrode.

In an effective embodiment of the spark gap, the third electrode has a hollow cylindrical shape into which the first and second electrodes extend. On the other hand, the first and second electrodes may have a hollow cylindrical shape into which the third electrode extends.

The invention will now be explained in more detail with reference to a drawing, which drawing successively shows in:

Figure 1 shows an embodiment of a high-voltage pulse generator device according to the invention;

Figure 2 shows a further embodiment of the high-voltage pulse generator device according to Figure 1;

Figure 3 shows another embodiment of a high-voltage pulse generator device according to the invention; Figure 4 shows a further embodiment of the high-voltage pulse generator device according to Figure 3;

Figures 5-9 show other embodiments of a high-voltage pulse generator device according to the invention;

Figures 10a-10c show different embodiments of a capacitor-spark gap combination according to the invention.

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Figure 1 shows a transmission line transformer 1 consisting of two transmission sections 1a and 1b, respectively. Each transmission section 1a and 1b is made up of a transmission line, which is coaxial and consists of at least one inner conductor 5 or outer conductor 6, each provided with an inner conductor input terminal and output terminal or an outer conductor input terminal and output terminal. Furthermore, the transmission lines 1a and 1b arranged in parallel are provided with an input side 7a and an output side 7b. According to the invention, each transmission section 1a-1b is provided with a capacitor-spark gap combination 2a-2b composed of a series of switched capacitor 4a, 4b and a spark gap 3a, 3b. Each spark bridge 3a, 3b is connected on the input side 7a to the inner conductor input terminal of the inner conductor b of each transmission line 1a and 1b, respectively. According to the invention, furthermore, on the input side 7a, the outer conductor input terminal of the outer conductor 6 of the transmission line 1a is connected to the capacitor 4b of the capacitor spark gap combination 2b of the transmission line 1b.

Due to the parallel coupling on the input side 7a of the transmission line 1a with the capacitor-spark bridge combination 2a of the transmission line 1b, a spark bridge voltage pulse delivered by the first spark bridge 3a leads to a "triggering" of the capacitor-spark bridge combination 2b, wherein the spark gap 3b also outputs a spark gap voltage pulse. Both delivered pulses are passed through the respective transmission lines. This configuration permits a simple synchronization of spark gage voltage pulses by simultaneously firing the spark gaps in a plurality of transmission lines, with the respective spark gaps 3a, 3b being minimally loaded. Due to the simultaneous excitation or synchronization of the various spark gaps 3a and 3b, a higher pulsed power can be passed through the transmission line transformer under low loading of the spark gaps in question.

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An application in which the spark bridge voltage pulses introduced at the input side 7a are amplified is shown at the output side 7b of Figure 1, wherein the outer conductor 6 of the transmission line 1a is connected to the inner conductor 5 of the transmission line 1b and the outer conductor 6 of the transmission line 1b is connected via a load 8 to the inner conductor 5 of the transmission line 1a. This configuration makes it possible to apply a voltage pulse applied to the input side of the transmission line transformer, so that at the output side 7b a voltage pulse is obtained which is twice as high. This boosting of a voltage pulse guided by the transmission line transformer takes place under the same load of the spark gap 3a. The voltage pulse led by the transmission line transformer is thus doubled, so that the high-voltage pulse generator device according to the invention can be used for industrial applications in which such voltage pulses are used. Because the spark gaps 3a, 3b are less stressed than usual for obtaining such high output voltage signals, the service life of the spark gaps is considerably extended. They can also be manufactured less robustly.

Figure 2 shows an extension of the embodiment shown in Figure 1 in which corresponding parts are designated with the same reference numeral. This embodiment has, instead of two, four transmission lines 1a-1d, which are mutually coupled in a corresponding manner, as described in Figure 1. At the input side 7a, the outer conductor 6 of each transmission line is connected to the capacitor of the capacitor spark gap combination of the next transmission line, while on the output side 7b the outer conductor 6 of each transmission line is connected to the inner conductor 5 of the next transmission line.

In short, the transmission lines on the input side 7a are connected in parallel to each other, while on the output side 7b they are connected in series with each other. The outer conductor 6 of the transmission line 1d is again connected on the output side 7b via a load 8 to the inner surface 5 of the transmission line 1a.

In this embodiment too, the creation of a spark bridge voltage pulse at the spark bridge 3a causes synchronized simultaneous release of the spark bridges 3b, 3c and 3d from the successive transmission lines Ib-1d. Thus, voltage pulses are simultaneously passed through the different transmission lines 1a-1d, which, due to the specific serial coupling on the output side 7b, results in a multiplication of the voltage pulse applied to the input side 7a. If a double voltage pulse is also created on the output side 7b in Figure 1, in the embodiment according to Figure 2 this input voltage pulse on the output side 7b is quadrupled.

It will be clear that the embodiment as shown in Figs. 1 and 2 can be expanded with an arbitrary number of transmission lines, which are correspondingly connected to each other on their respective input or output side, so that the voltage of the signal pulse on the output side 7b can be increased accordingly.

Figures 3 and 4 show two other embodiments of the high-voltage pulse generator device according to the invention. Here, too, corresponding parts have the same reference numerals as shown in Figures 1 and 2 described above. Figure 3 shows a transmission line transformer, which is composed of two coaxial transmission lines 1a and 1b parallel to each other, which are connected to their input side 7a connected in parallel to each other as described in Figures 1 and 2. Also on the output side 7b the transmission lines 1a-1b (Figure 3) and the transmission lines 1a-1d (Figure 4) are connected in parallel to each other.

Analogously to the embodiments according to Figures 1 and 2 ini 9, also with these embodiments according to Figures 3 and 4, all spark gaps are synchronized at the moment that the first spark gland 3a ignites and outputs a spark gage voltage pulse, which synchronization leads to the simultaneous delivery of a spark gage voltage pulse from the 5 other spark gaps, which spark bridge voltage pulses are simultaneously passed through the respective transmission lines 1a-1d. Because the respective transmission lines on their output side 7b are connected in parallel with each other, the voltage pulse on the output side 7b is equal to the input voltage pulse on the input side 7a. However, because the output impedance Salt is half (Figure 3) and one-fourth (Figure 4) respectively of the characteristic impedance of each individual transmission line, a signal pulse can be obtained on the output side 7b with a current intensity that is twice or four times higher. In fact, the high-voltage pulse generator devices of FIGS. 3 and 4 act as current multipliers.

By coupling a plurality of transmission lines together in an analogous manner, as shown in Figures 3 and 4, the current intensity of the signal pulse on the output side 7b can be increased accordingly.

Figures 5 and 6 show other specific applications of a high-voltage pulse generator device according to the invention.

The embodiment as shown in Figure 5 shows a transmission line transformer 1, which is composed of four transmission lines la-1d arranged in pairs. In these embodiments too, the corresponding parts are designated with the same reference numerals.

In Figure 5, the first pair is formed by the transmission lines 1a and 1b, while the second pair is formed by the transmission lines 1c and 1d. According to the invention, on the input side 7a, the transmission lines 1a-1d are connected in parallel with each other, so that a spark bridge voltage pulse created by the spark bridge 3a, which is conducted through the transmission line 1a, simultaneously igniting the other spark bridges 3b-3d and creating of a spark bridge voltage pulse through the other spark bridges 3b-3d, so that four spark bridge voltage pulses are simultaneously passed through the respective transmission lines la-1d. On the output side 7b, the transmission lines of each pair are connected in parallel with each other, whereafter the two pairs 1a-1b and 1c-1d are connected to each other in series. Thus, both the voltage and current multiplication occur in the transmission line transformer 1. In this embodiment, the voltage pulse applied on the input side 7a is increased on the output side 7b to a twice higher voltage pulse with a twice higher current intensity.

The embodiment shown in Figure 6 also shows a transmission line transformer composed of four transmission lines la-1d which are connected in parallel to each other on their input side 7a according to the invention and previously described exemplary embodiments. In this embodiment, each transmission line is separately connected to a load 8a-8d, thereby enabling the simultaneous use of the high-voltage pulse generator device according to the invention for four different applications.

In Figure 7, each transmission section 15a resp. 15b composed of two (or more) transmission lines 1a-1b resp. 1c-25d, the inner conductors 5 and the outer conductors 6 of which are mutually connected. These two transmission lines connected in parallel to each of sections 15a and 15a respectively. 15b are simultaneously ignited by the spark gap 3a resp. 3b. Here two transmission lines are controlled per spark gap. Voltage multiplication occurs on the output side 7b analogously to Figures 1 and 2.

Figure 8 shows another embodiment, in which the 11 transmission sections 15a and 15b are also composed of two series-connected transmission lines 1a-1b and 1b, respectively. lc-ld. Here, two transmission lines are also driven per spark gap, albeit serially, with the transmission line 1a (1c) driving the line 1b (1d). Current amplification occurs on the output side 7b analogously to Figures 3 and 4.

Figure 9 shows an application of a high voltage pulse generator device where the load 8 is a corona discharge chamber. In the chamber 18, a gas can be purified by means of corona discharges 10 from impurities, as described in the

International Patent Application No. PCT / NL96 / 00463. In order to positively influence the generation of corona discharges in the space 18, the interior of the transmission line 1a is connected to a charging voltage source 16 and the corona inner conductor 17a. With the aid of the torque capacitor Cdc, a (similar) voltage is applied from the source 16 to the inner conductor 17a, on which the signal pulse of the transmission line transformer is then superimposed.

The charging coil Ldc can optionally be placed between the coupling capacitor Cdc and the outer conductor 17b of the corona discharge space 18, in order to enable charging of the coupling capacitor Cdc by the source 16 if the inner conductor 5 of the transmission line 1a is not directly electrically grounded.

Figures 10a to 10c show embodiments of a capacitor-spark gap combination that can be used with the high-voltage pulse generator device according to the invention. In Figures 10a to 10c, the corresponding parts are designated with the same reference numerals.

By HV is meant a high voltage pulse source which charges the capacitor 4 by means of repetitive pulses. These charging pulses 30 may, for example, have a pulse width of 0.1-100 psec, with a pulse repetition frequency of 1 Hz to 10 kHz, with a peak voltage of 5 kV-12 200 kV and with both a positive or negative polarity. The spark gap 3 has three electrodes 10, 11 and 12 respectively, so-called spark gaps 13a 5 and 13b are present between the third "trigger" electrode 10 and the first electrode 11 and the second electrode 12, respectively. With the aid of the resonant circuit LCR, an uneven voltage distribution across the two spark gaps 13a and 13b is created by the high voltage pulse source HV during the charging cycle of the capacitor 4. At the moment that a too high voltage prevails over the spark gap 13a or 13b between the first or second electrode and the third "trigger" electrode 10, a spark gap voltage pulse is delivered to the transmission line transformer 1.

Figures 10b and 10c show other alternative embodiments of the spark gap 3 according to the invention, wherein the third "trigger" electrode 10 in Figure 10b is designed as a hollow cylindrical electrode, in which both the first electrode 11 and the second electrode 12 reaches.

In the other embodiment as shown in Figure 10c, the third "trigger" electrode 10 is embodied as a rod-shaped electrode, while both the first electrode 11 and the second electrode 12 are formed as hollow cylindrical electrodes, which are arranged over the rod-shaped "trigger". electrode 10.

It should be noted that for driving the transmission line transformer in the high-voltage pulse generator device according to the invention, the spark gap used can be designed as an arbitrary high-voltage switch. In addition to the traditional, classical spark gap consisting of two electrodes or in accordance with the embodiment shown in Figure 10, any other type of fast high-voltage switch can be used, including semiconductor switches (Solid State).

The essence of the invention lies in the ignition of one switch (spark gap), whereafter all other switches 13 ignite in synchronism. Because in this way each switch can be loaded with an input signal with a smaller current and / or voltage than in the already known applications, the service life thereof increases.

On the other hand, each switch can be separately loaded more, since the ratio between the output power of the high-voltage pulse generator and the power transmitted per switch increases. This makes it possible to use the device according to the invention for industrial use where stronger pulse signals are desired or required.

Furthermore, the high-voltage pulse generator device according to the invention can be expanded with an arbitrary number of transmission sections or lines and spark gaps, with which the voltage and current of the output pulse can be arbitrarily adjusted depending on the configuration on the input or output side.

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Claims (17)

High-voltage pulse generator device comprising at least a resonant charging circuit, a capacitor-spark gantry combination, and a transmission line transformer, wherein in operation the charging circuit charges the capacitor which ignites the spark gantry as soon as the voltage across the capacitor is high enough and thus creates a spark bridge voltage pulse guided by the transmission-line-transformer, characterized in that the transmission-line transformer is composed of two or more transmission sections, each section being provided with an input side and an output side and consisting of at least one transmission line constructed from at least one coaxial inner conductor with an inner conductor input terminal and an inner conductor output terminal and an outer conductor with an outer conductor input terminal and an outer conductor output terminal, each transmission section being separately coupled to a capacitor spark gap combination, such that the ignition and of a spark gap of a capacitor-spark gap combination initiates the ignition of all spark gaps of all capacitor-spark gap combinations. High-voltage pulse generator device as claimed in claim 1, characterized in that a transmission section composed of two or more transmission lines, wherein on the input side the respective inner conductor input terminals of the transmission lines mutually and the respective outer conductor input terminals of the transmission lines are interconnected. 3. High-voltage pulse generator device according to claim 1, characterized in that a transmission section is made up of two or more transmission lines, the outer conductor input terminal of a transmission line being connected to the inner conductor input terminal on the input side. of the next transmission line. «: R» 4. High-voltage pulse generator device as claimed in one or more of the foregoing claims, characterized in that the capacitor-spark bridge combination is composed of a series connection of a capacitor and spark bridge, wherein a free end of the spark bridge on the input side is connected to the inner conductor input terminal of a transmission section and that the outer conductor input terminal of the transmission section is connected to a free end of the capacitor of a subsequent capacitor spark gap combination of the next transmission section. High-voltage pulse generator device as claimed in one or more of the claims 1-4, characterized in that on the output side the outer conductor output terminal of a transmission section is connected to the inner conductor output terminal of the following transmission section. 6. High-voltage pulse generator device as claimed in one or more of the claims 1-4, characterized in that on the output side the respective inner conductor output terminals of the transmission sections mutually and the respective outer conductor output terminals of the transmission sections mutually with each other are connected. 7. High-voltage pulse generator device as claimed in one or more of the claims 1-4, characterized in that the transmission line transformer is composed of several pairwise coupled transmission sections, such that on the output side for each pair the outer conductor output terminal of the first transmission section is connected to the inner conductor output terminal of the second transmission section, furthermore the outer conductor output terminals of the second transmission sections of each pair are connected to each other and the inner conductor output terminals of the first transmission sections of each pair to each other be connected. 8. High-voltage pulse generator device as claimed in one or more of the foregoing claims, wherein on the output side the inner conductor output terminal of a transmission section is connected to an inner conductor and the outer conductor output terminal of the transmission section is connected to an outer conductor of a corona discharge space, characterized in that the inner conductor output terminal is also connected to a charging voltage source. 9. A high-voltage pulse generator device as claimed in Claim 8, characterized in that a coupling capacitor is arranged between the inner conductor output terminal and the inner conductor of the corona discharge space. 10. A high-voltage pulse generator device as claimed in Claim 9, 10, characterized in that a charging coil is placed between one side of the coupling capacitor and the outer conductor of the corona discharge space. High-voltage pulse generator device according to one or more of the preceding claims, characterized in that one or more transmission sections are provided with an envelope consisting of one or more kinds of magnetic material. 12. High-voltage pulse generator device according to one or more of the preceding claims, characterized in that a spark gap is designed as a semiconductor switch or another type of high-voltage switch. 13. Capacitor-spark gap combination for use in a high-voltage pulse generator device according to one or more of the preceding claims, comprising a capacitor that can be charged by a resonant charging circuit, and a spark gap connected in series with the capacitor 25 and consisting of at least a small distance first and second electrode spaced apart, thus forming a spark gap, the second electrode being connected at the input side to the inner conductor input terminal of a transmission section of the transmission-line transformer of the high-voltage pulse generator device, characterized that the spark gap is further provided with a third electrode. i • * ·! A capacitor-spark gap combination as claimed in claim 13, characterized in that the combination is furthermore provided with an LCR circuit, the coil L with the first electrode of the spark gap and the resistor R on the input side with the outer conductor input terminal of a The transmission section of the transmission line transformer is connected and the third electrode is connected between the capacitor C and the resistor R with the LCR circuit. A capacitor-spark gap combination according to claim 13 or 14, characterized in that the third electrode is placed in the spark gap between the first 10 and second electrode. A capacitor-spark gap combination according to claim 13 or 14, characterized in that the third electrode has a hollow cylindrical shape into which the first and second electrodes extend. A capacitor-spark gap combination according to claim 13 or 14, 15, characterized in that the first and second electrodes have a hollow cylindrical shape into which the third electrode extends. A capacitor-spark gap combination according to one or more of claims 13-17, characterized in that the spark gap is designed as a semiconductor switch or another type of high-voltage switch. 20 pounds