CN105207651B - The coaxial pulse of high impedance high voltage output forms line - Google Patents

Abstract

The invention belongs to the technical field of pulse power, and relates to a coaxial pulse forming line with high impedance and high voltage output. The advantages of reliable insulation and high output voltage are simultaneously realized in the pulse forming structure. The present invention consists of four parts which form a line section, a short-circuit switch section, an output switch section and a load section. The four coaxial cylinders forming the line section and the insulating filling medium form three pulse forming lines, and only the outer line is used for energy storage. The wave impedance ratio of the external line, neutral line and internal line is 4:3:12, the matching impedance of the load is 4 times the impedance of the energy storage external line, and the matching output voltage is equal to the forming line charging voltage. The invention adopts a single-line energy storage method with reliable insulation, but realizes a high-amplitude voltage output of twice the charging voltage; in addition, the matching output impedance is much higher than that of the Blumlein line, and the matching transmission efficiency for high-resistance loads is high.

Description

Coaxial pulse forming line with high impedance and high voltage output

technical field

The invention belongs to the technical field of pulse power, and relates to a coaxial pulse forming line with high impedance and high voltage output.

Background technique

In the field of pulse power technology, there are many methods for generating high-voltage pulses, among which single coaxial line (Document 1: S.D.Korovin, V.V.Rostov, S.D.Polevin, Pulsed power-driven high-power microwavesources, Proceedings of the IEEE, Vol.92, No.7; July 2004) and coaxial Blumlein lines (Document 2: J.C.Martin, Nanosecond pulse techniques, Proceedings of the IEEE, Vol.80, No.6; June 1992) are the most common pulse forming lines . The miniaturization of high-power pulse devices requires the maximum energy storage of pulse-forming lines, and the optimal impedance of pulse-forming lines mainly depends on the dielectric constant of the energy storage medium. In general, Blumlein lines have a higher output impedance than single coax lines. The single coaxial cable is composed of two coaxial cylinders, the inner cylinder and the outer cylinder, and the load matching output voltage amplitude is equal to half of the charging voltage of the single coaxial cable. The coaxial Blumlein line is composed of three coaxial cylinders, the inner cylinder, the middle cylinder and the outer cylinder. During the charging process, the cylinder is at a high potential, and the inner cylinder and the outer cylinder are at the same potential, that is, between the middle cylinder and the inner and outer cylinders. There is a voltage difference, and the load matching output voltage amplitude is equal to the charging voltage. The traditional single coaxial line and coaxial Blumlein line have the following disadvantages: the output voltage of the single coaxial line is low, and the insulation pressure of the coaxial Blumlein line double line energy storage is large during the charging process.

The coaxial two-stage reentrant pulse forming line (patent acceptance number: 201510262236.7) adopts coaxial external line energy storage, and adopts the reentrant structure of the coaxial two-stage pulse forming line to achieve three times the pulse width output of the general coaxial line, and the load is matched The impedance is three times that of the general coaxial line wave impedance. This technical solution can generate a wider pulse output and has high energy transmission efficiency for higher resistance loads. The disadvantage of this structure is that the matching output voltage is low, which is half of the charging voltage. For high voltage output requirements, the charging pressure for forming lines is relatively high.

Contents of the invention

In order to overcome the shortcomings of the low output voltage of the traditional single-wire energy storage and the difficulty in insulation of the double-wire energy storage of the Blumlein line, the present invention provides a coaxial pulse forming line with high impedance and high voltage output, which realizes reliable insulation at the same time on the same pulse forming structure and the advantages of high output voltage.

The technical solution formed by the present invention to solve its technical problems is:

A coaxial pulse forming line with high-impedance and high-voltage output includes a short-circuit switch section 1, a forming line section 2, an output switch section 3 and a load section 4 connected in sequence, and is characterized in that:

Described short-circuit switch section comprises rear end cover 17 and short-circuit switch, and described short-circuit switch comprises short-circuit switch anode 18, short-circuit switch cathode 19 and insulating filling medium, and described short-circuit switch cathode 19 is arranged on rear end cover inner side and short-circuit switch anode 18 relative and maintain a certain gap;

The forming line segment 2 includes four metal cylinders with gradually decreasing diameters and equal lengths, an end plate 21, an insulating filling medium, and a plurality of lead rods 16. The four metal cylinders are coaxially arranged and nested in sequence to form Line outer cylinder 14, cylinder B13, cylinder A12 and inner cylinder 11; wherein, one end of the cylinder B and the inner cylinder close to the short-circuit switch section is electrically connected through the end plate 21 arranged on the circumference, and the connection between the end plate and the cylinder B is the circumference Arranged circular arc section; one end of cylinder A and cylinder B close to the output switch is electrically connected through the circular arc section arranged around the circumference; the insulating filling medium is filled between adjacent metal cylinders and at the end to form a wire outer cylinder 14, The cylinder B13 and the insulating filling medium between the two cylinders form the outer line, the cylinder B13, the cylinder A12 and the insulating filling medium between the two cylinders form the middle line, and the cylinder A12, the inner cylinder 11 and the insulating filling medium between the two cylinders form the inner line, so The wave impedance ratio of outside line, center line and inside line is 4:3:12;

Guide holes 20 with the same number as the number of guide rods are provided on the end plate with the center of the inner cylinder as the center circumference, and the guide rods pass through the guide holes 20 on the end plate 21 and are coaxial with the guide holes 20;

The output switch section 3 includes an output switch outer cylinder 9 and an output switch disposed in the output switch outer cylinder, and the output switch includes an output switch anode 7, an output switch cathode 8 and a switching gas filled in the output switch. medium, the output switch anode 7 and the output switch cathode 8 maintain a certain gap distance;

The load section 4 includes a load outer cylinder 6, a load resistor and an insulating filling medium arranged in the load outer cylinder, and the insulating filling medium is filled between the load resistor 5 and the load outer cylinder 6;

One end of the forming line outer cylinder 14 near the short-circuit switch section is electrically connected to the rear end cover, one end of the forming line outer cylinder 14 close to the output switch is electrically connected to one end of the output switch outer cylinder, and the other end of the output switch outer cylinder One end is electrically connected to one end of the load outer cylinder;

One end of the guide rod is electrically connected to the anode of the short-circuit switch, and the other end of the guide rod passes through the guide hole 20 and is electrically connected to the end of the cylinder A close to the short-circuit switch;

One end of the inner cylinder close to the output switch is electrically connected to the cathode of the output switch;

One end of the load resistor is electrically connected to the anode of the output switch, and the other end of the load resistor is electrically connected to the other end of the load outer cylinder;

In the charging process, the outer cylinder 14 is grounded, and in the slow charging process, the three metal cylinders, the inner cylinder 11, the cylinder A12 and the cylinder B13, are charged with a high voltage U0 with equal amplitude, and the threshold of the short circuit switch is U0 , the threshold of the output switch is -2U0.

The matching resistance of the above-mentioned load segment 4 is 4 times that of the outer line forming the line segment 2 .

The plurality of guide rods are evenly distributed around the inner cylinder.

The present invention compares with prior art, beneficial effect is:

1. Reliable insulation of single-wire energy storage: The traditional Blumlein line can also achieve double the charging voltage of high-voltage output, but it is difficult to use double-wire energy storage insulation. The forming line segment 2 of the present invention is an integrated coaxial structure, including 4 metal cylinders nested together to form 3 pulse forming lines, only the outer line is used for energy storage, and the insulation is reliable.

2. High output voltage: The present invention adopts the re-entrant structure and the superposition method of series output voltage, so that the matching output voltage amplitude is equal to the charging voltage of the forming line, which achieves the effect of the traditional coaxial Blumlein line, and is beneficial to reduce the impact on the forming line. Charge pressure. Traditional energy storage single-wire output voltage is low - half of the charging voltage.

3. High output impedance: the present invention uses a reentrant structure and a series output structure, and the matching output impedance is 4 times that of the wave impedance of the external line used for energy storage, which is much higher than the output impedance of the traditional coaxial Blumlein line. Energy transfer to higher resistance loads is more efficient.

4. Use the combination of output switch and short-circuit switch to realize pulse output: in the slow charging process of forming line, when the short-circuit switch gap voltage reaches the threshold value U0, conduction occurs, and when the output switch gap voltage reaches U0, it does not conduct; when the output switch gap voltage reaches U0 Turn-on occurs when flipping rapidly to -2U0.

Description of drawings

Fig. 1 is a structural diagram of a coaxial pulse forming line with high impedance and high voltage output in the present invention.

FIG. 2 is a cross-sectional view of the wire structure formed in the present invention at the position of the left interface 15 .

Fig. 3 is a simulation circuit of the pulse forming line model of the embodiment.

Fig. 4 is the simulation waveform result of the embodiment.

In the figure, 1 short-circuit switch segment, 2 forming line segment, 3 output switch segment, 4 load segment, 5 load resistor, 6 load outer cylinder, 7 output switch anode, 8 output switch cathode, 9 output switch outer cylinder, 10 right interface, 11 inner cylinder, 12 cylinder A, 13 cylinder B, 14 forming line outer cylinder, 15 left interface, 16 lead rod, 17 rear end cover, 18 short-circuit switch anode, 19 short-circuit switch cathode, 20 opening, 21 end plate (shadow part), port 22-22', port 23-23', 24-central hole.

detailed description

The present invention will be described below in conjunction with the embodiments, and the embodiments refer to FIG. 3 .

Carry out finite element electromagnetic field simulation to the forming line segment 2 of the coaxial pulse forming line of the high-impedance high-voltage output of the present invention, the side of the left interface 15 is port 22-22', port 22 is equivalent to the anode base of the short-circuit switch, and port 22' is equivalent to To form the left end face of the outer cylinder of the line, the port 22-22' is connected to the switch element switch 1, the switch 1 is a short-circuit switch, and the side of the right interface 10 is the port 23-23', and the port 23 is equivalent to the right end face of the inner cylinder, and the port 23 ′ is equivalent to forming the right end face port 23-23 of the outer cylinder of the line, and is connected to the resistance element _RL with a resistance value of 63Ω through the switch element switch 2, and the switch 2 is an output switch, and the DC charging power supply with a voltage amplitude of U ₀ passes through the charging resistor R _ch Connect with the port discrete point 22 of the simulation model. The simulation model of forming line segment 2 adopts transformer oil medium, and the specific parameters are: the length of forming line segment is 1000mm, the inner diameter of forming line outer cylinder 14 is 450mm, the outer diameter of cylinder B13 is 304mm and inner diameter is 264mm, the outer diameter of cylinder A12 is 196mm and inner diameter is 190mm, and the inner diameter of inner cylinder 11 The outer diameter is 58mm. A line charge of 600kV is formed, and the field strength of the outer surface of the cylinder B 13 is 100kV/cm. During the discharge process, the surface field strength of the inner cylinder 11 is 130kV/cm, and the outer surface field strength of the cylinder A12 is 78kV/cm. The matching design impedance of the load is 63Ω, the output voltage is 600kV, and the pulse width is 10ns.

Fig. 4 shows the simulation waveform of the circuit in Fig. 3, and the output pulse simulation results are consistent with the theoretical design, wherein, V(22) and V(23) are the voltage waveforms of the port discrete points 22 and 23 respectively, respectively describing the formation of the line segment 2 in For the discharge conditions of the left end face 15 and the right end face 10, V(RL) is the voltage waveform of the load resistance element _RL .

Now in conjunction with embodiment, accompanying drawing, the working principle of the pulse forming process of the present invention is further described:

The 4 coaxial cylinders forming the line segment and the insulating filling medium constitute 3 pulse forming lines (outer line, middle line and inner line), assuming the charging voltage U ₀ of cylinder B 13, the electrical length of the formed line is τ (where τ= _lεr ^1/2 /c, l is the axial length of the formed line, c is the speed of light in vacuum, ε _r is the relative permittivity of the insulating filling medium). The short-circuit switch and the output switch are closed successively. After the switch is closed, when the electromagnetic wave is transmitted on the transmission line, the reflection and transmission behavior of the wave will occur when it encounters an interface with discontinuous impedance. Assume that the cross section where the end plate 21 is located is the left interface 15 , and assume that the cross section where the electrical connection ends of the barrel B 13 and the barrel A 12 is located is the right interface 10 .

When the output switch is not closed, several specific wave propagation behaviors of the wave at the discontinuous interface include:

1) Short circuit switch closing behavior. After the short-circuit switch is turned on, the transmission line through which the short-circuit voltage wave travels is equivalent to the parallel connection of the inner and middle lines and then in series with the outer line. When the wave impedance ratio of the outer line, the middle line and the inner line is 4:3:12, the generated short-circuit voltage wave (position 15 on the left interface) is transmitted to the inner, outer, and center lines at the same time, and the amplitudes are (-3/8)(- U ₀ ), (3/8)(-U ₀ ), and (5/8)(-U ₀ ).

2) When the output switch is not closed, the transmission behavior of the line voltage wave on the right interface 10 is formed. Open-circuit reflections occur on both internal and external line voltage waves, with the same amplitude and polarity. The neutral voltage wave is short-circuited and reflected, with the same amplitude and opposite polarity.

3) The transmission behavior of the external line voltage wave on the left interface 15 . At this time, the short-circuit switch is in the conduction state, and the transmission line through which the transmitted wave travels is equivalent to a parallel connection of inner and neutral lines. At a certain moment, when the voltage wave of the outside line (assuming the voltage wave amplitude U _x ) is transmitted to the left interface 15, the transmission and reflection of the wave occurs: when the wave impedance ratio of the outside line, the middle line and the inside line is 4:3:12, a part of the voltage amplitude The transmitted wave of (3/4) U _x is transmitted to the inner line; a part of the transmitted wave with the voltage amplitude of (-3/4) U _x is transmitted to the neutral line; the reflected wave with the voltage amplitude of (-1/4) U _x Return to outside line.

4) The transmission behavior of the neutral voltage wave on the left interface 15. At this time, the switch is in the conduction state, and the transmission line through which the transmitted wave travels is equivalent to a parallel connection of the inner and outer lines. At a certain moment, when the voltage wave on the neutral line (assuming voltage wave amplitude U _y ) is transmitted to the left interface 15, matching transmission of the wave occurs, no reflected wave returns from the neutral line, and the voltage wave amplitudes transmitted to the inner and outer lines are both (-1) U _y .

5) The transmission behavior of the internal line voltage wave on the left interface 15 . At this time, the switch is in the conduction state, and the transmission line through which the transmitted wave travels is equivalent to the parallel connection of the middle and outer lines. When the wave impedance ratio of the outside line, the middle line, and the inside line is 4:3:12, when the voltage wave of the inside line (assuming the voltage wave amplitude U _z ) is transmitted to the left interface 15 at a certain moment, the transmission and reflection of the wave occurs: a part of the voltage amplitude The transmitted wave with (1/4) U _z transmits to the outer line; a part of the transmitted wave with the voltage amplitude of (-1/4) U _z transmits to the center line; the reflected wave with the voltage amplitude of (-3/4) U _z Return to the internal line.

According to the wave transmission analysis after the short-circuit switch is closed at time t=0, the output switch gap voltage -2U ₀ at time t=3τ is obtained, and the output switch has an overvoltage breakdown at this time. Before and after the breakdown of the output switch, the transmission behavior of the line-to-line voltage wave at the right interface 10 remains unchanged, while the transmission behavior of the inner and outer lines at the right interface 10 changes. After the output switch is closed, several specific wave propagation behaviors of the wave at the discontinuous interface include:

6) Output switch closure behavior. At t=3τ, the output switch is closed, and the transmitted voltage wave with the amplitude of -U ₀ is transmitted to the matching load; when the wave impedance ratio of the outer line, the middle line and the inner line is 4:3:12, the generated switch reflected wave ( 10 on the right interface) to the inner and outer lines, with amplitudes of (3/4) U ₀ and (1/4) U ₀ respectively.

7) At time t=3τ, the transmission behavior of the external line voltage wave on the right interface 10 (the output switch is in the ON state at this time). When the voltage wave of the outside line (assuming the voltage wave amplitude U _p ) is transmitted to the right interface 10 at a certain moment, the transmission and reflection of the wave occurs: when the wave impedance ratio of the outside line, the middle line and the inside line is 4:3:12, a part of the voltage amplitude The transmitted wave of U _p is transmitted to the load; a part of the transmitted wave with the voltage amplitude of (-3/4) U _p is transmitted to the inner line; the reflected wave with the voltage amplitude of (3/4) U _p returns to the outer line.

8) The transmission behavior of the internal line voltage wave on the right interface 10 (the output switch is in the ON state at this time). When the voltage wave of the inner line (assuming the voltage wave amplitude U _q ) is transmitted to the right interface 10 at a certain moment, the transmission and reflection of the wave occurs: a part of the transmitted wave with the voltage amplitude U _q is transmitted to the load; when the wave of the outer line, the middle line and the inner line When the impedance ratio is 4:3:12, a part of the transmitted wave with the voltage amplitude of (-1/4) U _q is transmitted to the inner line; the reflected wave with the voltage amplitude of (1/4) U _q returns to the outer line.

According to the wave transmission analysis of the above interfaces, the overall wave process of pulse formation can be described as:

The outer cylinder 14 of the formed line is grounded. During the slow charging process, the three metal cylinders, the inner cylinder 11, the cylinder A12 and the cylinder B 13, are charged with high voltages with equal amplitudes, and the energy is stored in the outer wire; during the discharge process, the short circuit switch pilot When the output switch gap voltage reaches twice the charging voltage, it will be turned on, and the load will output pulses at this time. The matching impedance of the load is 4 times the impedance of the energy storage external line, the output voltage amplitude of the matching load is equal to the charging voltage of the forming line, and the output pulse width is twice the length of the forming line.

1) At time t<0, the initial voltage difference U ₀ of the outer line, and the initial voltage difference between the neutral line, the inner line and the load are 0.

2) At time t=0, the short-circuit switch is turned on, and a step voltage wave from the left interface 15 appears on the external line, with an amplitude of (5/8)(-U ₀ ), making the external line voltage become (3/8)U ₀ ; A step voltage wave from the left interface 15 appears on the center line, with an amplitude of (3/8)(-U ₀ ), making the center line voltage become (-3/8)U ₀ ; a step voltage wave from the left interface 15 appears on the inner line A jump voltage wave with an amplitude of (-3/8)(-U ₀ ), making the internal line voltage change to (3/8)U ₀ .

3) At time t=τ, a step voltage wave from the right interface 10 appears on the outside line, with an amplitude of (5/8)(-U ₀ ), making the voltage on the outside line change to (-1/4)U ₀ ; The step voltage wave coming from the right interface 10, the amplitude (-3/8)(-U ₀ ), makes the neutral line voltage become 0; the inner line appears a step voltage wave coming from the right interface 10, the amplitude (-3/8) 8)(-U ₀ ), so that the internal line voltage becomes (3/4)U ₀ .

4) At time t=2τ, a step voltage wave from the left interface 15 appears on the outside line, with an amplitude of (1/8)(-U ₀ ), making the voltage on the outside line change to (-3/8)U ₀ ; The step voltage wave from the left interface 15 has an amplitude of (-3/8)(-U ₀ ), so that the neutral line voltage becomes (3/8)U ₀ ; the inner line appears a step voltage wave from the left interface 15, The amplitude is (9/8)(-U ₀ ), so that the internal line voltage becomes (-3/8)U ₀ .

5) At time t=3τ, the output switch is turned on, and a step voltage wave appears on the matched load, with an amplitude of -U ₀ ; a step voltage wave from the right interface 10 appears on the outside line, with an amplitude of (-1/8)(-U ₀ ), making the outer line voltage become (-1/4) U ₀ ; a step voltage wave from the right interface 10 appears on the center line, with an amplitude of (3/8)(-U ₀ ), making the center line voltage become 0; A step voltage wave from the right interface 10 appears on the inner line, with an amplitude of (3/8)(-U ₀ ), so that the inner line voltage becomes (-3/4)U ₀ .

6) At time t=4τ, a step voltage wave from the left interface 15 appears on the outer line, with an amplitude of (-1/4)(-U ₀ ), so that the outer line voltage becomes 0; the middle line does not appear from the left interface 15 Step voltage wave, the voltage remains at 0; a step voltage wave from the left interface 15 appears on the inner line, with an amplitude of (-3/4)(-U ₀ ), making the inner line voltage become 0.

7) At time t=5τ, a step voltage wave appears on the matching load with an amplitude of U ₀ , so that the load voltage becomes 0; the step voltage wave from the right interface 10 does not appear on the inner, middle and outer lines, and the voltage remains at 0 constant.

According to the analysis of the pulse forming wave process, the output voltage amplitude of the matching load is equal to the charging voltage of the forming line, the polarity is opposite, and the output pulse width is 2τ; the line is subjected to bipolar pulse voltage during the discharge process, and the amplitude is 3U ₀ /8, different The duration of the polarity is 2τ; the inner line is subjected to bipolar pulse voltage, the amplitude is 3U ₀ /4, and the duration of different polarities is 2τ.

Claims (3)

1. high impedance high voltage output coaxial pulse formed line, including be sequentially connected short switch section (1), formed line segment (2), output switch section (3) and load patch (4), it is characterised in that：

The short switch section includes rear end cap (17) and short switch, the short switch include short switch anode (18), Short switch negative electrode (19) and insulation filling medium, the short switch negative electrode (19) is arranged on the inside of rear end cap and short switch Anode (18) is relative and keeps certain interval；

The formation line segment (2) is gradually reduced including 4 diameters and the metallic cylinder of equal length, end plate (21), insulation filling Medium and it is multiple draw bar (16), 4 metallic cylinders are to be coaxially disposed and formation line outer barrel (14) nested successively, cylinder B respectively (13), cylinder A (12) and inner cylinder (11)；Wherein, the end plate that cylinder B and inner cylinder are set close to one end of short switch section by circumference (21) electrically connect, the end plate and cylinder B junction are the arc section that circumference is set；Cylinder A and cylinder B is close to one end of output switch The arc section set by circumference electrically connects；The insulation filling Filled Dielectrics are between adjacent metal cylinder and end, shape Into between line outer barrel (14), cylinder B (13) and two insulation filling medium formed outside line, cylinder B (13), cylinder A (12) and two it Between insulation filling medium form center line, insulation filling medium between cylinder A (12), inner cylinder (11) and two forms interior lines, institute The wave impedance ratio for stating outside line, center line and interior lines is 4:3:12；

Circumference is provided with and drawn bar quantity identical guide hole (20) centered on inner cylinder center on the end plate, and the bar that draws is worn The guide hole (20) crossed on end plate (21), and it is coaxial with guide hole (20)；

The output switch section (3) includes output switch outer barrel (9) and the output switch being arranged in output switch outer barrel, described Output switch includes output switch anode (7), output switch negative electrode (8) and the switch being filled in output switch being oppositely arranged Gas medium, output switch anode (7) and output switch negative electrode (8) keep certain clearance distance；

The load resistance and insulation filling medium that the load patch (4) includes load outer barrel (6) and is arranged in load outer barrel, absolutely Edge filled media is filled between load resistance (5) and load outer barrel (6)；

The line outer barrel (14) that formed is electrically connected close to one end of short switch section with rear end cap, and the formation line outer barrel (14) is leaned on One end of nearly output switch electrically connects with one end of output switch outer barrel, the other end and the load outer barrel of the output switch outer barrel One end electrical connection；

Described one end for drawing bar electrically connects with short switch anode, and the other end for drawing bar leans on through guide hole (20) with cylinder A One end electrical connection of nearly short switch；

The inner cylinder electrically connects close to one end of output switch with output switch negative electrode；

One end of the load resistance electrically connects with output switch anode, and the other end of the load resistance is with loading the another of outer barrel One end electrically connects；

In charging process, formed line outer barrel (14) ground connection, during charging battery inner cylinder (11), cylinder A (12) and cylinder B (13) this Three metallic cylinders fill the equal high voltage U0 of amplitude with, and the threshold value of the short switch is U0, the threshold value of the output switch For -2U0.

2. the coaxial pulse of high impedance high voltage output according to claim 1 forms line, it is characterised in that：

The matching resistance of described load patch (4) is form line segment (2) outside line 4 times.

3. the coaxial pulse of the high impedance high voltage output according to any claim of claim 1 to 2 forms line, its It is characterised by：It is the multiple to draw bar circumference uniform distribution centered on inner cylinder.