RU2352039C1 - Multielement switchboard - Google Patents

Abstract

FIELD: electrics.

SUBSTANCE: switchboard includes a number of sequential threshold commutation elements (dischargers P1÷P10) forming straight current duct, with outputs featuring weak capacitance connection to reverse current duct 1 of switchboard, and two splitter circuits out of passive capacitance elements. Each main passive capacitance element (C1÷C5) of first splitter circuit is connected parallel to neighbour commutation elements starting from first P1 and second P2 elements. Each main passive capacitance element (C6÷C9) of second splitter circuit is connected parallel to two neighbour commutation elements starting from second P2 and third P3 elements. Each of two additional passive capacitance elements C10, C11 of second splitter circuit is connected parallel to one commutation element (P1, P10). Short launch impulse is put to clamp 8.

EFFECT: possible increase of commuted voltage and switchboard application in high voltage devices with nanosecond process synchronisation against launch impulses, reduce power loss and switchboard closing time.

2 cl, 2 dwg

Description

The invention relates to high-voltage pulse technology and is intended for use in shapers of nanosecond voltage pulses used, for example, in high-current accelerators of charged particles.

Known multi-element switch in the form of a multi-gap arrester (Humphreys DR, Penn KJ, Cap JS et. Al, Rimfire: A Six Megavolt Laser - Triggered Gas-Filled Switch for PBFA II, Proc. 5 th Intern. IEEE Pulsed Power Conf, Arlington, 1985 , pp.262-266), which is a series (chain) of series-connected threshold switching elements - arresters (discharge gaps), which form a direct current lead. The reverse current lead of the switch is formed by a conductive housing in which the chain of switching elements is located. The chain of switching elements is divided into two series-connected sections - the main and starting. The start-up section consists of one switching element (spark gap), triggered by gas ionization, performed using a laser beam directed into the discharge gap. The capacitive coupling of switching elements with a reverse current lead is negligible compared to the capacitive coupling of the spark gap electrodes to each other, i.e. the capacitances of the electrodes form a dividing circuit, which ensures uniform distribution of the switched voltage across the switching elements.

The disadvantage of this switch is the need to use a significant length of the start-up section (start-up spark gap) to provide a voltage surge sufficient to start the main section, the use of a powerful laser source and the relatively slow increase in voltage on open-gap arresters of the main section, which is realized during switching by redistributing the switched voltage between open arresters. The result is a relatively large variation in switch closure time (jitter).

Also known is a multi-element switch made in the form of a gas multi-gap arrester (Volkov S.I., Kim A.A., Kovalchuk B.M. et al. Multi-channel closing arrester for water storage devices. Izvestiya Vuzov. Physics, 1999, No. 12, p. .91-99), which is a modification of the previous arrester. Its main difference is the use of a multi-gap design of the starting section, in parallel with which are connected in series inductance (transmitting helical line) and a starting arrester, through which a starting voltage pulse is supplied.

The disadvantage of this switch is the need to use a powerful triggering pulse to start the switching process, delaying the front of the triggering pulse on the transmitting spiral line and the relatively slow increase in voltage at the discharge gaps in the switching process, arising due to the redistribution of the switched voltage between open dischargers and, as a result, a relatively large the spread of the closure time of the switch.

Closest to the proposed technical solution (prototype) is a multi-element switch in the form of a gas multi-element arrester (US patent No. 2659839, July 17, 1951), including a series (chain) of series-connected arrester (switching elements) forming a direct current lead, in parallel with which is connected dividing circuit consisting of series-connected resistors. The arrester has passive elements in the form of capacitances connected between the electrodes of the arrester and the return current path of the switch (case or "ground wire"). The magnitude of the capacitance of each of these passive elements is significantly greater than the magnitude of the capacitance between the electrodes of each spark gap (strong capacitive coupling of the leads of the spark gap with the reverse current lead of the switch). The control input is connected to the midpoint of the resistive dividing circuit, with the connection point of two adjacent discharge gaps. In another version of the control circuit, there is an additional discharge gap in it, upon closure of which the resulting ultraviolet radiation contributes to the closure of other discharge gaps. In the initial state, the capacitances connected between the electrodes of the discharge gaps and the housing (reverse current lead) of the switch are charged to the voltages determined by the resistive dividing circuit. The appearance of voltage at the control input of the switch, due to the redistribution of voltages between capacitive elements, causes overvoltage at adjacent discharge gaps and, as a result, their closure (breakdown). As a result of voltage equalization at the capacities adjacent to the closed discharge gap, an approximately 1.5-fold increase in voltage occurs in the adjacent discharge gap, which leads to its quick breakdown (closure), so the switching process sequentially extends to all discharge gaps.

The disadvantage of the prototype is the limited possibility of its use for switching high voltages, because due to the mismatch of the resistive distribution of the switched voltage across the circuit of the switching elements and the distribution in accordance with capacitive coupling, an inhomogeneous electric field is formed that greatly limits the value of the switching voltage. Another disadvantage of the prototype is the heat loss on the resistors from the current flowing through the resistive circuit that distributes the switching voltage between the switching elements, which is especially important when the switch is in frequency modes.

The objective of the invention is to create a switch using a uniform capacitive distribution of the switched voltage between the switching elements, in which the switching process is initiated by closing one of the switching elements and quickly spreads to the remaining elements, which allows the switch to be used for switching high voltages with a small (nanosecond) spread of switching time.

To solve the problem in a multi-element switch, which includes a series of series-connected threshold switching elements forming a direct current path and having a certain amount of capacitance between each output of the threshold switching element and the return current path of the switch, as well as the first dividing circuit in the form of series-connected main passive elements connected in parallel threshold switching elements, and the main capacitive passive elements, the capacity of each of which The capacitance between the terminals of each threshold switching element is much larger, the second dividing circuit is introduced, capacitive passive elements are used as the main passive elements of the first and second dividing circuits, each main capacitive passive element of the first dividing circuit is connected in parallel to two adjacent threshold switching elements, starting from the first and a second threshold switching element and so on until the last threshold switching element, if it is even, or to the penultimate threshold switching element, if the number of threshold switching elements in the switch is odd, each of the main capacitive passive elements of the second dividing circuit is connected in parallel to two adjacent threshold switching elements, starting from the second and third threshold switching element and so on until the last threshold switching element, if it is odd, or to the penultimate threshold switching element, if the number of threshold switching elements the switch is even, and if the number of threshold switching elements in the switch is even, then two additional capacitive passive elements are introduced into the second dividing circuit, one of which is connected parallel to the first and the other parallel to the last threshold switching element, and if the number of threshold switching elements in the switch is odd then an additional capacitive passive element is introduced into the first dividing circuit, connected in parallel with the last, odd threshold switching element, when for this purpose, an additional capacitive passive element is introduced into the second dividing circuit, connected in parallel with the first threshold switching element, the threshold switching elements are placed relative to the reverse current lead of the switch so that the capacitance between each terminal output of the threshold switching element and the reverse current lead of the switch is significantly smaller than the capacitance of the main capacitive passive elements .

2. The multi-element switch according to claim 1, characterized in that the capacitance values in the switch correspond to the following conditions:

Sd> (5 ÷ 100) · N · St,

Sd> (10 ÷ 100)

Sdd = 2

Where

SD - the value of the capacitance of the main capacitive passive element connected in parallel to two threshold switching elements, pF;

N is the number of threshold switching elements in the switch;

St is the value of the capacitance between the output of the threshold switching element and the reverse current lead of the multi-element switch, pF;

Ck is the value of the capacitance between the terminals of each threshold switching element, pF;

SDD - the value of the capacitance of an additional capacitive passive element connected in parallel with one threshold switching element, pF.

The proposed technical solution has novelty, because in comparison with the prototype in it instead of a resistive dividing circuit, the elements of which are connected in parallel to each threshold switching element, two dividing circuits are used, made only of capacitive passive elements, each of which (with the exception of two such elements) It is connected in parallel to two threshold switching elements, and instead of a strong one, a weak capacitive coupling of the switching elements with the return current of the switch is used. The above set of distinctive features is not revealed in the known analogues.

The technical result of the proposed technical solution is to increase the permissible value of the switched voltage (due to the coordinated capacitive distribution), reduce the energy loss during switching (due to the absence of the resistive current distribution), as well as reduce the switch closure time and its spread (due to the combination of the voltage doubling process by open switching elements, when the adjacent switching element is closed, with the process of increasing voltage due to redistribution switching voltage between the remaining open elements).

The use of the capacitance values indicated in an additional paragraph of the formula in the proposed switch ensures an optimal mode of operation of the switch.

The invention is illustrated by drawings:

figure 1 - diagram of a multi-element switch on arresters with an even number of switching elements;

figure 2 - the implementation of a multi-element switch on dynistors with an odd number of switching elements.

The multi-element switch shown in Fig. 1 contains a row (tuple) of ten series-connected threshold switching elements (dischargers P1, P2, P3, P4, P5, P6, P7, P8, P9, P10 with their discharge gaps) located relative to the reverse current lead 1 so that the value of the capacitance St between each terminal of each arrester P1 ÷ P10 and the reverse current lead 1 is significantly less than the capacitance of the main capacitive passive element Cd. The number of arresters in the switch of figure 1 is even. The return current lead 1 is shown conditionally.

The switch of FIG. 1 also includes a first dividing circuit in the form of five passive elements connected in series - main capacitances C1, C2, C3, C4, C5, connected in parallel to these arresters, each of these capacitors being connected in parallel to two adjacent arresters. The capacitance C1 is connected in parallel with the first P1 and second P2 surge arresters. The capacitance C2 is connected in parallel with the third P3 and the fourth P4 arresters and so on by analogy (as shown in figure 1). The switch of FIG. 1 contains an even number of dischargers (ten), therefore, each two of ten dischargers corresponds to a parallel connected main capacitance. The last capacitance C5 is connected in parallel with the two last rated arresters P9, P10.

In addition, in the switch of FIG. 1 there is a second dividing circuit in the form of six passive elements connected in series - additional capacitance C10, main capacitances C6, C7, C8, C9 and additional capacitance C11, connected in parallel with the arresters P1 ÷ P9. Each of the main capacitances C6 ÷ C9 of the second dividing circuit is connected in parallel to two adjacent dischargers, starting from the second P2 and third P3 of the arrester and so on until the penultimate arrester P9, since the number of dischargers in the switch of FIG. 1 is even. That is, the last main capacitance C9 of the second dividing circuit is connected in parallel with two penultimate dischargers P8, P9 of the switch of FIG. 1. Additional capacitance C10 is connected in parallel with the first spark gap P1, additional capacity C11 is connected in parallel with the last spark gap P10.

The first terminal 2 of the first arrester P1 (Fig. 1) is connected to one input terminal 3 of the switch, the other input terminal 4 of the switch is connected to the return current lead 1, to which the output terminal 5 of the switch is also connected. Another output terminal 6 of the switch is connected to the last terminal 7 of the last arrester P10. Between the output terminals 5, 6 of the switch, the load Zн can be connected.

The electrical circuit from terminal 3 to terminal 6, together with the switching elements, is the direct current path of the switch.

The switch starting terminal 8 of FIG. 1 is connected to a connection point 9 of the terminals of the capacitance C10 and one terminal of the resistor Z1, the other terminal of which is connected to the connection point 10 of the input terminal 3 and terminal 2 of the arrester P1. A resistor Z2 (shown by a dotted line) connected between the capacitance C11 and terminal 7 of the arrester P10 can also be introduced into the switch circuit.

The return current lead 1 can be grounded (11) and, if necessary, can be the case of a multi-element switch.

The multi-element switch of figure 2 contains a series of nine series-connected threshold switching elements, which are used dynistors D1, D2, D3, D4, D5, D6, D7, D8, D9. These dinistors are located between the input terminal 3 and the output terminal 6 and face the positive terminals in the direction of the input terminal 3, to which a positive switching voltage is applied. The value of the capacitance St between each terminal of each dynistor D1 ÷ D9 and the return current path 1 of the switch is less than the value of the capacitance Cd. The number of dinistors in the switch of FIG. 2 is odd. Connections with reverse current lead 1 in figure 2 are not shown.

The first dividing circuit of the switch of FIG. 2 includes five series-connected passive elements - the main capacitances C1, C2, C3, C4 and additional capacitance C11. The main capacitances C1 ÷ C4 are connected in parallel to the dynistors D1 ÷ D8, each of these capacities is connected in parallel to two neighboring dinistors. Capacity C1 is connected in parallel with the first D1 and second D2 dynistors. The capacitance C2 is connected in parallel with the third D3 and the fourth D4 dynistors and so on by analogy (as shown in figure 2). The last capacitance C4 of the first dividing circuit is connected in parallel with the dynistors D7 and D8. Additional capacity C11 is connected in parallel with the D9 dinistor.

In the switch of FIG. 2 there is a second dividing circuit in the form of five passive elements connected in series - additional capacitance C10 and main capacitances C6, C7, C8, C9. Additional capacity C10 is connected in parallel with the D1 dinistor. The main capacitances C6 ÷ C9 are connected in parallel to the D2 ÷ D9 dynistors, and each of these capacities is connected in parallel to two neighboring dynistors, starting from the second D2 and third DZ of the dynistor and so on until the last dynistor D9, since the number of dynistors in the switch of FIG. 2 is odd . The last capacitance C9 of the second dividing circuit is connected in parallel with the last pair of dinistors D8, D9 of the switch of FIG. 2.

The first (positive) terminal 12 of the first dinistor D1 (FIG. 2) is connected to the input terminal 3 of the switch, the other output terminal 6 of the switch is connected to the last (negative) terminal 13 of the last dinistor D9.

In the embodiments of the switch of FIGS. 1 and 2, the values of the main capacitances of the first and second dividing circuits (C1, C2, C3, C4, C5, C6, C7, C8, C9), each of which is connected in parallel to two threshold switching elements, correspond to the following optimal conditions:

Where

SD - the value of the capacitance of the main capacitive passive element connected in parallel to two threshold switching elements, pF;

N is the number of threshold switching elements in the switch;

St is the value of the capacitance between the output of the threshold switching element and the reverse current lead of the multi-element switch, pF;

Ck is the value of the capacitance between the terminals of each threshold switching element, pF.

Moreover, the values of each of the main capacities are the same within the accuracy of their manufacture for any number of threshold switching elements in the switch circuit.

The above ranges of capacitance values Сд (from 5 to 100 values of N · CT and from 10 to 100 values of CK) are optimal for the switch. Values greater than those indicated can, but not practical, be used, since this is associated with large energy losses. The value of the capacitance Cd, more than 5 times the value of N · ST, is significantly larger than the value of Art. The value of the capacitance Cd, which is 10 or more times higher than the value of Ck, is significantly larger than the value of Ck.

The values of the additional capacitance of the dividing circuits C10 and C11 (figures 1 and 2), each of which is connected in parallel with one switching element, correspond to the condition:

Where

SDD - the value of the capacitance of a capacitive passive element connected in parallel with one threshold switching element, pF;

SD - the value of the capacitance of a capacitive passive element connected in parallel to two threshold switching elements, pF.

The values of each of the additional containers are the same within the accuracy of their manufacture. Typically, the value of the additional capacity is chosen equal to twice the value of the main capacity. This ensures the uniformity of the voltage values acting in the initial state on all switching elements without exception and equal conditions for the operation (closure) of all threshold switching elements (optimal switch operation mode).

As the threshold switching elements can be used as arresters (gas, liquid, dielectric), as shown in figure 1, and other elements with threshold characteristics of the on-off input voltage, for example, dynistors (figure 2), reversible diodes, in particular, type HEXFRED company International Rectifier (not shown in the drawings). When using reversible diodes as switching elements, the latter should face the negative terminals towards the input terminal 3 (Fig. 2), to which a positive voltage is applied.

The presence of a resistor Z1 (Fig. 1) between the first additional capacity of the second dividing circuit and the input terminal 3 of the switch provides isolation of the starting circuit with terminal 8 from the input circuit with terminal 3 of the switch. Similarly, the resistor Z2 can be used in the case of applying a trigger pulse to the extreme (on the right in FIG. 1) terminal of capacitance C11.

The switching process is started by applying a voltage pulse to the input terminal 8 of the switch.

It is also possible to start the switching process of FIG. 1 by supplying laser radiation to any of the discharge gaps of the arresters P1 ÷ P10 (not shown in the drawings). The start of the switch can also be realized by a corresponding increase in the switching voltage at the input terminal 3.

The required parameter values of capacitive passive elements in the switch of FIGS. 1 and 2 can be provided both by using capacitors included in the dividing circuits between the terminals of the switching elements, and by choosing the appropriate shape, size and relative position of the terminals of adjacent threshold switching elements, for example electrodes arresters.

The operation of the multi-element switch of FIG. 1 is described below with an even number of threshold switching elements in the form of arresters, with the following parameters: SD = 100 pF, SDD = 200 pF, St = 1 pF, C = 5 pF, Z1 = 1000 Ohm, Z2 = zero, the input impedance of the switch circuit is 25 Ohms, Zн is zero (make switch). The initial switched voltage on the switch is 500 kV, the amplitude of the triggering pulse is 25 kV, the duration of the triggering pulse is 5 nsec.

When the source (switched) voltage is insufficient for breakdown of the discharge gaps at the input terminals 3, 4 of the switch, the circuit is charged from the main capacitive passive elements (capacities) C1, C2, C3, C4, C5, C6, C7, C8, C9 and additional capacitive passive elements (capacities) C10, C11. The circuit of the switch comes to its original state, in which dividing circuits from the indicated capacitances provide a uniform distribution of the initial voltage across the threshold switching elements (here, the arresters P1 ÷ P10). That is, on each switching element in the initial state, a voltage is applied, N times less than the initial voltage, where N is the number of switching elements connected in series in the switch. Moreover, each of the main capacitances C1 ÷ C9 is charged to a voltage of N / 2 less than the initial voltage applied to the terminals 3, 4 of the switch, that is, twice as much voltage acting on each of the switching elements. Each of the additional capacitances C10 and C11 is charged to a voltage equal to the voltage acting on each of the switching elements, since the value of each of them is twice as large as the value of each of the main capacities C1 ÷ C9.

The voltage value acting on each of the threshold switching elements in the specified initial state is selected so that there is no breakdown of the discharge gaps of the arresters P1 ÷ P10.

When a triggering pulse is applied to terminal 8 with an amplitude sufficient to increase the voltage across the discharger P1 to the breakdown value of its discharge gap, the discharger P1 closes, as a result of which the voltage of the main capacitance C1 of the first dividing circuit, equal to twice the voltage previously applied to this arrester, and the arrester P2 also closes. When the arrester P2 closes, a double voltage of the main capacitance C6 of the second dividing circuit is applied to the arrester P3, equal to the double voltage previously applied to this arrester, so that the arrester P3 closes. A similar process takes place with all arresters, a switching wave propagates through the switch until the last of the P10 arresters closes. The switch is closed. Thus, in the switching process, even without taking into account the redistribution of the switched voltage between the capacitances of the dividing circuits, which are interfaced with open key elements, a double increase in the voltage applied to the closable gap of the switching element occurs, which ensures a quick switching process of individual switching elements and the switch as a whole. Opening the switch occurs after the termination of the switched current.

A switch with threshold switching elements in the form of dinistors (Fig. 2), in which the switching voltage is initially applied to terminal 3, after applying a trigger pulse to terminal 8, it works similarly to the switch of Fig. 1, except that the dinistors operate as threshold switching elements D1 ÷ D9. Dinistors (such as arresters and reversing diodes) turn on when they reach a voltage that exceeds the voltage of the turn-on threshold, and turn off (recover) after the switching current is stopped. When starting fast-ionizable dinistor and reverse-diode switches, it is required to provide the necessary voltage growth rate (more than 1 kV / ns per semiconductor structure) on the switched switching element (Grekhov I.V., Kardo-Sysoev A.F., Kostina L.S. , Shenderey S.V. // ZhTF, 1981, v. 51, v. 11, p. 1709-1711).

Claims (2)

1. A multi-element switch comprising a series of series-connected threshold switching elements forming a direct current path and having a certain capacitance between each terminal output of a threshold switching element and a reverse current path of a switch, as well as a first dividing circuit in the form of series-connected main passive elements connected in parallel with threshold switching elements , and the main capacitive passive elements, the magnitude of the capacitance of each of which is significantly larger than the capacitance between the terminals of each threshold switching element, characterized in that a second dividing circuit is inserted into the switch, capacitive passive elements are used as the main passive elements of the first and second dividing circuits, each main capacitive passive element of the first dividing circuit is connected in parallel to two adjacent threshold switching elements, starting from the first and second threshold switching element, and so on until the last threshold switching element, if it is even m, or to the penultimate threshold switching element, if the number of threshold switching elements in the switch is odd, each of the main capacitive passive elements of the second dividing circuit is connected in parallel to two adjacent threshold switching elements, starting from the second and third threshold switching elements, and so on until the last threshold switching element, if it is odd, or to the penultimate threshold switching element, if the number of threshold switching element s in the switch is even, and if the number of threshold switching elements in the switch is even, then two additional capacitive passive elements are introduced into the second dividing circuit, one of which is connected parallel to the first and the other parallel to the last threshold switching element, and if the number of threshold switching elements in the switch is odd, then an additional capacitive passive element is inserted in the first dividing circuit, connected in parallel with the last, odd threshold switching element, at the same time, an additional capacitive passive element is included in the second dividing circuit, connected in parallel with the first threshold switching element, the threshold switching elements are located relative to the reverse current lead of the switch so that the capacitance between each terminal output of the threshold switching element and the reverse current lead of the switch is significantly less than the capacitance of the main capacitive passive passive elements. 2. The multi-element switch according to claim 1, characterized in that the capacitance values in the switch correspond to the following conditions:
Sd> (5 ÷ 100) · N · St,
Sd> (10 ÷ 100)
Sdd = 2
where Cd is the value of the capacitance of the main capacitive passive element connected in parallel to two threshold switching elements, pF;
N is the number of threshold switching elements in the switch;
St is the value of the capacitance between the output of the threshold switching element and the reverse current lead of the multi-element switch, pF;
Ck is the value of the capacitance between the terminals of each threshold switching element, pF;
SDD - the value of the capacitance of an additional capacitive passive element connected in parallel with one threshold switching element, pF.

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