RU2003219C1 - Magnetic pulse oscillator - Google Patents

Description

The present invention relates to nanosecond pulsed technology and is intended for charging the generating lines of accelerators, as well as for exciting pulse-periodic gas lasers and other devices with non-linear characteristics.

Generators of high-power high-voltage nanosecond pulses based on magnetic compression links are known whose capacitances are made from blocks of standard capacitors. For example, a generator for exciting high-power repetitively pulsed gas lasers generates pulses of 20 kV amplitude on a capacitive load, with a front duration of 300 ns, following at a frequency of 3000 Hz. The generation of pulses with shorter edges in tens of nanoseconds is limited due to the large parasitic inductance of the generator links, which consists mainly of the inductance of the mounting of the capacitor units and the substantial intrinsic inductance of the capacitors. As a result of this, the efficiency of such generators does not exceed 50 + 60%.

When unipolar voltage pulses are formed on the load at the beginning of each subsequent pulse, all ferromagnetic cores of the generator must be returned to their initial magnetic state in the region of their negative saturation.

Nanosecond pulse generators based on magnetic compression links are known in which the preliminary demagnetization of the ferromagnetic cores of the links is carried out using additional demagnetization windings arranged on the cores and fed in series from one or in parallel from several current sources.

The disadvantage of such generators is their complexity and reduced reliability due to the large number of additional windings and power supplies.

Generators are also known in which the preliminary demagnetization of the ferromagnetic cores of compression links is carried out through the main working windings of these cores by the charge current of the capacitance of the input link of the generator from a switching power supply. However, the use of such generators is limited since this charge current also closes through the load. In the case of a load with a pronounced nonlinear characteristic, such as, for example, an electrode system of a gas laser, the use of such generators without the use of special additional circuits shunting the load is impossible.

The closest known technical solutions to this proposal

is a magnetic pulsed generator containing a pulsed power supply, an input link, consisting of a charged LC circuit, a switch, a compression link, including saturation chokes, made in

in the form of toroidal ferromagnetic cores covered by magnetization turns to which capacitors are connected. The generator also contains a demagnetizing system with a source

current. The output link of the generator is connected to the load.

A switching power supply and one power supply are connected to the magnetization coils of the first compression link through the input LC link

the output of the demagnetization system located on the inner surface of the saturation chokes and the second free output connected to a current source. A feature of the generator is that

that instead of standard ones, it uses special strip capacitors. In this case, the capacitor plates of each compression link are made equal in width to the height of the set of chokes cores

saturation, divided into parts and laid in a spiral of Archimedes on top of the chokes. In turn, the windings of saturating reactors are divided into 2 l of turns, except for the winding of the drossel of the output link, made in

in the form of a continuous turn. Potential capacitor plates are connected to the external terminals of the turns, and other plates, grounded, are connected to the housing. Terminals located on the inside

the surface of the chokes, windings are interconnected. In this case, structurally, all compression stages are placed in a common cylindrical housing.

With this embodiment of the generator, during operation of the capacitor plates with the magnetizing coils, they form a coaxial or symmetrical stripe line that is connected to the load. it

eliminates matching transmission lines, minimizes spurious inductance of the installation, and also by significantly reducing the intrinsic inductance of capacitors improves the ratio of inductances of turns of saturation chokes to compression stages and inductances of capacitors. The consequence of this is an increase in the generator efficiency and the possibility of generating nanosecond pulses with steep fronts on the load, on the order of several tens of nanoseconds.

The disadvantages of this device are: firstly, the difficulty of obtaining high-power high-voltage pulses with an amplitude of the order of 100 kV or more in the load, since all the main elements of the generator from the switching power source to the output compression link must be made almost at the full load voltage, secondly, the demagnetization of all the ferromagnetic cores of the compression stages by a common coil passing through the central part of the housing and powered from a low-voltage source, significantly complicates the design the generator and makes it difficult to match the output link-compression with the load, because between them the homogeneity of the coaxial high-voltage junction is violated, which should be very low inductance.

All this significantly reduces the reliability of the generator and limits the possibility of its use.

The aim of the invention is to increase the reliability of the generator and enable it to work on a non-linear load, as well as simplifying its design and operation.

This goal is achieved in that in the proposed magnetic pulsed generator, as in the prototype, containing a pulsed power supply including a capacitive energy storage device, a switch and a step-up pulse transformer, an input link, a demagnetizing system including a capacitive energy storage, a switch and a step-up pulse transformer an input link demagnetizing system, including ballast inductance and current source, as well as compression links located in a common cylindrical housing, including saturation donkeys made in the form of toroidal ferromagnetic cores covered by magnetization turns, to which capacitors are connected, made in the form of strip lines laid in an Archimedes spiral on top of saturation chokes, in contrast to the prototype, the generator input link is made of two series-connected capacitors, where parallel to the first the secondary winding of the pulse transformer of the switching power supply is connected to the capacitor, and the demagnet is connected in parallel to the second capacitor a reference system, while the ballast inductance of the system is connected to a common point of connection of the capacitors, and the output compression link is connected to pulsed single-turn transformers of coaxial design, the windings of which are made of a number of parallel turns covering the transformer core and radially distributed between the housing and the central output electrode generator. At the same time, both the compression link and single-turn

0 transformers are located in a common cylindrical housing.

The significant difference between the proposed device lies in the fact that in addition to compression in time obtained at

In the 5th stage of the capacitive energy storage of the switching power supply relative to the low voltage pulse, its amplitude is increased by a 1, 6, 9 times in the input link and 2 + 4 times in the output of the generator immediately before the load. This makes it possible to use low voltage standard elements, including powerful ones, for a pulse source and an input link; semiconductor frequency

5 switching devices, and on the elements of the compression links to have a voltage 2-4 times less than that formed in the load. As a result, the reliability of the generator is significantly increased, and its design and operation are simplified. In addition, the connection of the demagnetization system to the common point of the series-connected capacitors of the input link and the use of the generator output

5 single-coil coaxial transformers allow, without practically degrading the time and energy characteristics of pulses in the load, to demagnetize all ferromagnetic cores

0 generator, not shorting the demagnetization current through the load and not using additional demagnetization windings. This makes it possible to ensure reliable operation of the generator on both linear and

5 and a non-linear load, including the interelectrode gap of a gas pulsed laser.

In FIG. 1 shows a schematic diagram of the proposed generator; in FIG. 2

0 - diagrams of currents and voltages in generator elements: in FIG. 3-4 are diagrams illustrating his work.

In the figures indicated: I, II - single-turn pulse transformers, 1 5 generator housing, 2 - capacitive energy storage. 3 - commutator, 4 - step-up pulse transformer, 5, 6 - input link capacitors, 7.8 - compression link capacitors, 9 - input saturation choke, 10, 11 - inductors

saturation of compression links, 12 — ballast inductance, 13 — constant current source, 14 — magnetizing coils of pulse transformers, I, I, 15 — ferromagnetic toroidal cores of pulse transformers I, H, 16 — load resistor, 17 — interelectrode load gap, 17 - interelectrode load gap, 18 - central output electrode, 19 - voltage on the capacitive storage 2, 20 - voltage on the capacitor 5, 21 - voltage on the capacitor 6, 22 - voltage on the capacitor 7, 23 - voltage on the capacitor 8: 24 - voltage in currents e, f on pulse transformer output 1.25 - voltage at points, k, m at the generator output. 26 - capacitor charge current 5, 6, 27 - saturation throttle current 9, 28 - saturation throttle current 10.29 - saturation throttle current 11, 30 - current at the output of a pulse transformer in the df section, 31 - current in resistor 16 (at plot fm).

The magnetic pulse generator contains a switching power supply, including a capacitive energy storage 2, discharged through a switch 3, for example, a thyristor, to the primary winding of a boost pulse transformer 4. A capacitor 5 is connected in parallel with the secondary winding of this transformer, forming a capacitor 6 connected in series with it a saturation reactor 9; an input link of the generator. The ballast inductance 12 of the demagnetization system, powered by the demagnetization current from the direct current source 13, is connected to the common point of the connection of the capacitors 5.6 and the secondary winding of the pulse transformer 4. The value of the ballast inductance 12 is chosen so that it does not substantially bypass the capacitor 6 during charging .

A magnetic pulse generator contains several compression links, each of which has a saturation inductor Ш, 11, which, like the saturation inductor 9 of the input element, are made in the form of toroidal ferromagnetic cores covered by magnetizing coils. The potential terminals of the corresponding capacitors 7, 8 are connected to the external terminals of these turns, the other plates of which are grounded and are connected to the housing 1. Structurally, the condensers of the 7.8 compression stage are made in the form of strip lines laid in a spiral of Archimedes around their saturation chokes {see FIG. 3).

The last, output compression link is connected to pulse coaxial single-turn transformers I and II, the primary windings of which 14 with

the purpose of the most inductive performance are made of a number of parallel turns, covering the toroidal ferromagnetic core 15 of the corresponding transformer and radially

0 are distributed between the housing and the central output electrode 18 of the generator. Structurally, the input link inductor 9, the compression link, and pulse transformers I and tl are located in a common cylindrical housing 1. In this case, the internal leads of the drossel windings of the output compression link and pulse transformers I and Н are interconnected and form the central output electrode 18 of the generator,

0 which is made in the form of a cylinder and forms a coaxisle with case 1 (see Fig. 3), to which load 18 is connected. This generator is capable of exciting almost any type of load. In this

5, a nonlinear load of the interelectrode gap type of a pulsed gas laser is considered; FIG. 1 is shown as a series-connected resistor 16 and a gap 17.

0 The device operates as follows. In the initial state (t ti), the capacitors 5-8 of the input and compression links are discharged, and the capacitive storage 2 is charged with the one indicated in FIG. H polarity. From

5 of the DC source 13, the demagnetization current 1p flows through the inductance 12, which closes along the secondary circuit of the pulse transformer 4, the winding of saturation chokes 9-11 and

0 parallel connected windings of 14 pulse transformers {and II. This current demagnetizes completely to the state of negative saturation - BS- core of transformer 4 and throttle 9

5 of the input link, since their windings have a significant number of turns and single-turn transformers I and II are partially demagnetized. When turning on at time t of the switch 3 NC0, the discharge of the capacitive storage 2 through the primary winding of the pulse transformer 4 is started. The voltage induced on its secondary winding through the capacitor b and saturated inductor 9

5 is applied to the windings of the chokes 10, 11 and transformers, I. By demagnetizing their cores also completely to the magnetic state - BS. As a result, the input capacitors 5.6 with respect to the secondary winding of the transformer 4 are connected in parallel and are charged over time to the required maximum voltage value Uo of the switching power supply of FIG. 2, diagrams 20, 21, respectively. At time t.2, the charging process ends, switch 3 is turned off. Under the action of the voltage of the capacitor 5 through its secondary winding. Starting at time t2, the core of the throttle 9 leaves negative saturation and begins to magnetize, since an increasing voltage equal to the sum U of the voltages of the capacitors 5, 6 ceasing to balance each other begins to be applied to its winding. At time t3, when the process of recharging the capacitor 5 is close to completion and U (1, 9) Uo, the core of the cross-link 9 is saturated again, but already by induction + BS. Its inductance decreases by a factor of i, where магнит is the relative magnetic permeability of the core material and the process of discharging the series-connected capacitors 5, 6 through the winding of the saturated cross-link 9 to the capacitor 7 of the subsequent compression link begins. Under the action of the voltage of the capacitor 5, a current flows through the secondary winding of the transformer A, which transfers its core to an unsaturated state, which prevents the reverse charging of the capacitor 5 through the transformer winding.

At time t.4, capacitor 7 is charged to voltage U, and capacitors 5, G are discharged to zero.

The process of discharging the capacitor 7 to the capacitor 8 is similar to the process described above, however, the duration of the discharge of the capacitor 7 to the capacitor 8 is much shorter (time period te-ts, diagrams 22, 23 in Fig. 2). As the impulse is transferred from link to link, its duration decreases, reaching the desired value at the last link. In this case, the voltage amplitude remains approximately constant, and the amplitude of the current pulse increases in proportion to a decrease in its duration.

After saturation of the core, the throttle 11 of the last compression link begins to discharge the capacitance 8 of the last link to a single-coil winding 14 of the pulse transformer I. The direction of winding of the turns 14 of the transformers I. H is determined by the purpose of the generator. When generating very high voltage pulses at a high impedance load, the turns 14 are made so that the EMF induced by the transformers I, II on the central output electrode 18 coincides with the EMF of the capacitor 8 of the last compression unit. In this case (see

FIG. 3) transformers I and II turn on according to an autotransformer boost circuit, where the primary turn connected to the output link is turn a, b, d. c, a, and two secondary turns - b, e, f, d. b for transformer I and e, k, m, f, e, for transformer I. In order to reduce the leakage fluxes and, therefore, the minimum inductance, the transformers are made with a turn 14 almost completely covering the core 15. As a result, the voltage from the output of the last compression link is increased by each transformer (1.6 + 1.9) times with the corresponding

a decrease in current, taking into account the core magnetization current l / g. not transmitted to the load. It should be noted that the magnitude of the magnetization current (hundreds of amperes - units of kiloamperes) is much less than the magnitude of the current

loads (tens - hundreds of kiloamperes). The cross section of the transformer I is determined by the voltage U at the output of the last compression link and the pulse duration tH in the load

g and

 4 V s K st

where Bs is the saturation induction of the core material of the transformer, Ket is the fill factor with steel. Cross section of the core

transformer doubles.

When the generator is operating on a low impedance load. when the main thing is to obtain relatively low-voltage pulses with a very high current, the turns 14 of the transformers I and I are performed opposite to the above, so that the transverse direction induced on the axis of the EMF of the transformer

EMF of the capacitor of the last compression unit (see Fig. 4). Here, the transformers are turned on by

an autotransformer step-down circuit where the primary two turns, for example, for transformer I, is circuit a, b, d. c, and secondary loop b, e. f. d. 8 as a result, the current received from the last stage of compression increases at each transformer by (1., 9} times, but

with a corresponding decrease in voltage. As in the previous case, the windings 14 are made as close as possible to the cores 15: from a series of parallel turns covering the cores of the transformers and radially distributed between the housing and the central output electrode, and the cross section of the transformer I is determined by the voltage at the output of the last compression link and the duration pulse in the load. Further, the cross section of the core of each subsequent transformer is approximately halved. Thus, in the proposed device, in contrast to the prototype, in addition to time compression of a relatively low-voltage pulse received during discharge of a capacitive energy storage device, its amplitude is increased by 1.6-1.9 times in the input link and 2-4 times by generator output immediately before loading. This allows the elements of the compression links to have a voltage 2-4 times lower than that generated by the load and use low voltage standard elements for the pulse source and input link, which significantly increases the reliability of the generator, simplifies its design and operation. Connecting the demagnetization system to the common point of connection of the input capacitors and using single-turn transformers at the output of the generator, practically without affecting the time and

energy characteristics of the pulses in the load, allows to demagnetize all the ferromagnetic cores of the generator, without shorting the demagnetization current through the load and without using additional demagnetization windings. This allows without additional complication of the generator-load transition and without the use of additional devices

the possibility of reliable operation of the generator for both linear and non-linear loads such as interelectrode gap.

In the proposed device, in order to simplify the design and operation of the generator. during its operation in a continuous continuous pulse-periodic mode with a constant pulse repetition rate of tens to hundreds of pulses per second, the source may be excluded

DC in the demagnetization system. In this case, it is made in the form of a circuit of series-connected ballast inductance 12 and a resistor, where the inductance is connected to a common point

connection of capacitors 5, 6 of the input link, and the resistor to the housing 1.

thirty

(56) Copyright certificate of the USSR No. 152T224, cl. H 03 K 3/53, 1987.

Claims (1)

The claims A MAGNETIC PULSE GENERATOR comprising a switching power supply, including a capacitive energy storage device, a switch and a step-up pulse transformer, the secondary winding terminals of which are the first and second output terminals of the switching power supply, an input compression link, N compression links that are located in a common housing , the output link of compression, including saturation chokes made in the form of toroidal ferromagnetic cores covered by magnetizing coils, and capacitors made in the form e strip lines laid in a spiral of Archimedes over saturation chokes, a load and a demagnetizing system, including a ballast inductance connected in series and a current source, characterized in that the input capacitor the generator is made of two series-connected capacitors, the first capacitor connected in parallel with the first and second output terminals of the switching power supply, and the second capacitor connected in parallel with the demagnetizing system, the ballast inductance of the system connected to a common connection point of the first and second capacitors, output terminals of the output compression links are connected to the input terminals of pulse single-turn transformers, which are made coaxial and whose windings are razovany adjacent parallel coils spanning the transformer cores and distributed radially between the housing and the central electrode of the generator output. ABOUT tl / 7 U 8 V, / 4 G5 / l tf „ / I / at b / / e / // l , / ft / I i I / eighteen Figl