A pulse compression device

Abstract

This invention discloses a pulse compression device that solves the technical problems of existing pulse compression devices, such as low pulse compression energy efficiency, large switching jitter, poor operating stability, and the fact that reducing jitter by significantly advancing the switching operating point leads to a further decrease in pulse compression energy efficiency. The pulse compression device of this invention includes an input transmission line, a stepped transmission line, a low-resistance forming line, a switch S, and a load R. L The pulse compression device of the present invention utilizes multi-stage reflected voltage waves within a stepped transmission line to achieve multiple injections into the low-resistance forming line, while simultaneously achieving input matching (i.e., the input pulse has no reflection at the interface between the input transmission line, the transmission line, and the low-resistance forming line). Therefore, it theoretically achieves lossless pulse compression, which can increase the input pulse power by n times, shorten the pulse width to 1 / n, and achieve 100% energy efficiency.

Description

Technical Field

[0001] This invention relates to a pulse power device, and more specifically to a pulse compression device. Background Technology

[0002] Pulsed power technology has wide applications in particle accelerators, complex electromagnetic environment simulation, plasma generation, and wastewater and waste gas treatment. High power and high efficiency are the perpetual pursuits in the development of pulsed power technology. In pulsed power systems, in addition to high-power pulse sources (such as high-power pulse sources based on single-tube pulse forming lines and high-power pulse sources based on Blumlein forming lines), pulse compression devices are usually included. The function of the pulse compression device is to compress and shape the output pulses generated by the high-power pulse source to further shorten the pulse width and increase the power. During pulse compression, maintaining high energy efficiency while increasing power becomes a major technical challenge.

[0003] There is a pulse compression device based on nanosecond transmission line charging technology, such as Figure 1 As shown, this device was proposed by American scholar James P. O'Loughlin in 1995 (James P. O'Loughlin. Nanosecond transmission linecharging apparatus: United States, 5444308[P]. 1995-08-22). This pulse compression device consists of a high-resistance transmission line T1, a low-resistance forming line T0, a switch S, and a load R. L The circuit consists of the following components: T1 is the input transmission line; T0 is a short line in which the propagation time of the electromagnetic wave is much shorter than the pulse width of the input pulse to be compressed; the initial state of switch S is open; and the load R... L The impedance is the same as that of T0. The principle of this pulse compression device is as follows: the input pulse is incident into the high-impedance transmission line T1, and then transmitted through T1 into the low-impedance forming line T0; within T0, the transmitted voltage wave is reflected back and forth multiple times by the switch S and T1, and the reflected voltage waves at each stage are superimposed to form a step-like rising high voltage; when the switch S is turned on, T0 supplies power to the load R. L Discharge generates an output pulse with a shorter pulse width and higher power than the input pulse.

[0004] In the aforementioned pulse compression process, to achieve the goal of voltage wave reflection and superposition within T0, the impedance of T1 must be higher than that of T0 (typically, the impedance of T1 needs to be much higher than that of T0) so that T1 can positively reflect the voltage wave within T0. That is, T1 and T0 are actually in an impedance mismatch state. Therefore, the input pulse will inevitably be reflected during its injection from T1 into T0. The reflected voltage wave returns to the preceding high-voltage pulse source via T1, while the transmitted voltage wave enters T0. This portion of the voltage wave transmitted into T0 loses some energy each time it is reflected by T1 during the reflection and superposition process within T0. In other words, even the energy transmitted into T1 is not fully utilized. For these reasons, the theoretical energy efficiency of existing pulse compression devices does not exceed 80%.

[0005] Because the voltage wave inside T0 loses some energy with each reflection by T1, another disadvantage arises: as the reflection and superposition process continues, the amplitude of the reflected voltage wave decreases step by step, resulting in a smaller and smaller increase in the voltage amplitude per step inside T0. Macroscopically, the voltage amplitude increase inside the low-resistance forming line T0 exhibits a saturation trend. This saturation trend is detrimental to the conduction characteristics of switch S, because it means that the voltage rise rate across switch S is low before it turns on. Whether it's a gas switch or a solid-state semiconductor switch, a low voltage rise rate leads to increased switch jitter and decreased operational stability.

[0006] In practical engineering applications, to minimize switching jitter, the operating point of switch S often needs to be advanced significantly to close and conduct while the voltage rise rate is still high within T0. However, this inevitably results in a portion of the input pulse width not being utilized. Typically, to achieve sufficiently low switching jitter, the utilization efficiency of the input pulse width does not exceed 2 / 3. For this reason, the experimentally tested energy efficiency of existing pulse compression devices is usually no more than 50%, significantly lower than the highest theoretical value of approximately 80%.

[0007] In summary, the main problems with existing pulse compression devices are: 1. Due to inherent impedance mismatch, the energy efficiency of pulse compression is low; 2. The voltage amplitude growth inside the low-resistance forming line T0 shows a saturation trend, resulting in large switching jitter and poor working stability; 3. Attempting to reduce jitter by significantly advancing the switching operating point will further reduce the energy efficiency of pulse compression. Summary of the Invention

[0008] The purpose of this invention is to solve the technical problems of existing pulse compression devices, such as low pulse compression energy efficiency, large switching jitter causing poor working stability, and the further reduction in pulse compression energy efficiency caused by using the method of significantly advancing the switching operating point to reduce jitter. Therefore, this invention provides a pulse compression device.

[0009] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0010] A pulse compression device, characterized by:

[0011] Including input transmission lines Stepped transmission lines, low-resistance forming lines Switch S and load R L n is the order, n≥2;

[0012] The stepped transmission line includes n-1 segments of transmission lines of equal electrical length connected sequentially. Transmission lines ... transmission lines and transmission lines The transmission line Short-circuit the output port;

[0013] The low-resistance forming line The electrical length is the same as the electrical length of a single segment of transmission line in a stepped transmission line;

[0014] The input transmission line The input port is used to connect to an external high-power pulse source;

[0015] The transmission line The input port and low impedance form a line After the input ports are connected in series, connect the input transmission line. The output port;

[0016] The switch S and the load R L One end is connected in series, and the other end is connected to a low-resistance forming wire. The output port;

[0017] The transmission line Short-circuit the output port;

[0018] The input transmission line Forming lines with low resistance The impedance ratio is n, and the transmission line Transmission lines ... transmission lines and transmission lines Forming lines with low resistance The impedance ratios are n(n-1) / n, (n-1)(n-2) / n, ..., 3·2 / n, 2·1 / n.

[0019] Furthermore, the low-resistance forming line The electrical length is determined as follows:

[0020] Pulse wave forming line at low resistance The propagation time τ is 1 / 2n of the pulse width.

[0021] Furthermore, the closing time of the switch S is determined according to the following method:

[0022] Define the wavefront propagation of a pulse wave to the input transmission line. Transmission lines and transmission lines If the time at the interface is t=0, then the closing time of switch S is t=(2n-1)τ.

[0023] Furthermore, the input transmission line Stepped transmission lines and low-resistance forming lines It can be a coaxial line, microstrip line, or parallel plate line.

[0024] Furthermore, the switch S is a gas switch, a solid switch, or a liquid switch.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] 1. The pulse compression device of the present invention utilizes multi-stage reflected voltage waves within a stepped transmission line to achieve low-resistance forming line compression. Multiple injections simultaneously achieve input matching (i.e., the input pulse wave is on the input transmission line). Transmission lines Low-resistance forming line Since there is no reflection at the interface, lossless pulse compression is theoretically achieved, which can increase the power of the input pulse wave by n times, shorten the pulse width to 1 / n, and achieve 100% energy efficiency.

[0027] 2. During the operation of the pulse compression device of the present invention, a low-resistance forming line... The internal voltage amplitude increases in a step-like manner, which ensures that the switch S maintains a high voltage rise rate before conduction, which helps to reduce switch jitter and improve the stability of switch operation.

[0028] 3. In practical engineering applications, the pulse compression device of the present invention has high input pulse width utilization efficiency because the switch S has small jitter and there is no need to advance the switch operating point significantly. Attached Figure Description

[0029] Figure 1 Here is a schematic diagram of an existing pulse compression device;

[0030] Figure 2 This is a schematic diagram of the pulse compression device according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the coaxial second-order pulse compression device in an embodiment of the present invention;

[0032] Figure 4 The experimental waveforms of the coaxial second-order pulse compression device in the embodiment of the present invention are shown. Detailed Implementation

[0033] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0034] Figure 2 A schematic diagram of a pulse compression device according to this embodiment is provided. The device consists of an input transmission line. Stepped transmission lines with short circuits at the ends ~ Low-resistance forming line Switch S, load R L It consists of n-1 segments of the same electrical length, where the positive integer n is the order (n≥2); the stepped transmission line consists of n-1 segments of the same electrical length. Transmission lines ... transmission lines Transmission lines The transmission line T is formed by connecting the two ends of the line sequentially. n-1 The input port has a transmission line at the end. The output port is short-circuited at the end.

[0035] The electrical connection method for the pulse compression device is as follows: the input port of the stepped transmission line and the low-resistance forming line. After the input ports are connected in series, connect the input transmission line. The output port; switch S and load R L After being connected in series, a low-resistance forming line is connected. The output port.

[0036] Low resistance forming line Its electrical length is the same as that of a single segment of transmission line in a stepped transmission line. Input transmission line Forming lines with low resistance The impedance ratio is n, and the transmission lines in the stepped transmission line... Transmission lines ... transmission lines Transmission lines Forming lines with low resistance The impedance ratios are, in order: n(n-1) / n, (n-1)(n-2) / n, ..., 3·2 / n, 2·1 / n. The initial state of switch S is open.

[0037] Set low resistance forming line If the impedance is Z0, then the input transmission line The impedance is Z n =nZ0, the impedance Z of each segment of the stepped transmission line. n-1 Z n-2 ..., Z1 is:

[0038] (1)

[0039] Assume the pulse wave forms on the low-resistance forming line The propagation time in (or a single segment of a stepped transmission line) is τ.

[0040] The following analysis is performed when the pulse width is... A square wave pulse is incident on the input transmission line After the input port, the propagation process in the pulse compression device. The power of the square wave pulse. and energy They are respectively:

[0041] (2)

[0042] (3)

[0043] Because the square wave pulse is on the input transmission line The propagation process in this embodiment can be omitted, so the wavefront of the square wave pulse just propagates to the input transmission line. Transmission lines Low-resistance forming line The time at the interface is t=0. For ease of analysis, three corollaries and their proofs are given first.

[0044] Corollary 1: When the wavefront of the injected square wave pulse reaches the interface of each adjacent transmission line inside the stepped transmission line, it will be immediately reflected to generate a backward voltage wave with an amplitude of -V0 / n.

[0045] prove:

[0046] The injected square wave pulse first enters the transmission line and low resistance forming line Voltage is divided between them, where the transmission line Partial pressure coefficient for:

[0047] (4)

[0048] Adjacent transmission lines in a stepped transmission line and At the interface, From the transmission line To the transmission line Transmission coefficient and transmission lines To the transmission line Reflectance coefficient They are respectively:

[0049] (5)

[0050] (6)

[0051] At time t=iτ, the wavefront of the injected square wave pulse arrives and At the interface, reflection occurs, The generated backward voltage wave for:

[0052] (7)

[0053] Corollary 1 has been proven.

[0054] Corollary 2: When two subsequent voltage waves with the same amplitude but opposite polarities originate from low-resistance forming lines... and transmission lines Propagation to the input transmission line Transmission lines Low-resistance forming line When they meet at the interface, they will reflect and transmit each other at that interface. The overall result can be equivalent to both of the following voltage waves undergoing total internal reflection at the interface, with no energy entering the input transmission line. middle.

[0055] prove:

[0056] From the low-resistivity formation line To the input transmission line Transmission coefficient , forming lines from low resistance To the transmission line Transmission coefficient From the input transmission line and transmission lines Towards low resistance forming line Reflectance coefficient They are respectively

[0057] (8)

[0058] (9)

[0059] (10)

[0060] From the transmission line To the input transmission line Transmission coefficient From the transmission line Towards low resistance forming line Transmission coefficient , forming lines from low resistance and input transmission line To transmission line Reflectance coefficient They are respectively:

[0061] (11)

[0062] (12)

[0063] (13)

[0064] Set at the low resistance forming line The amplitude of the propagating voltage wave is V0 / n, and it travels along the transmission line. The amplitude of the propagating backward voltage wave is -V0 / n, and their wavefronts propagate simultaneously to the input transmission line. Transmission lines Low-resistance forming line The interface between the two traveling voltage waves. At this point, the two traveling voltage waves will be reflected and transmitted at this interface. Ultimately, a low-resistance line will form. Total forward voltage waveform fed in , to transmission line Total forward voltage waveform fed in and input transmission line The total backward voltage waveform fed in They are respectively:

[0065] (14)

[0066] (15)

[0067] (16)

[0068] Equations (14) and (15) can be equivalently regarded as: forming a low-resistance line The propagating voltage wave with an amplitude of V0 / n and the voltage wave at T n-1 The backward voltage wave with an amplitude of -V0 / n propagating in the middle is all on the input transmission line Transmission lines Low-resistance forming line Total internal reflection occurs at the interface. Equation (16) shows that no energy enters the input transmission line at this time. middle.

[0069] Corollary 2 has been proven.

[0070] Corollary 3: When forward voltage waves and backward voltage waves with the same amplitude and polarity arrive at the interface of two transmission lines at the same time, after mutual reflection and transmission at the interface, the overall effect can be equivalent to both voltage waves being unreflected at the interface and continuing to propagate while maintaining their original amplitude and polarity.

[0071] prove:

[0072] Assuming a forward voltage wave with an amplitude of -V0 / n and subsequent voltage wave Simultaneously arriving at adjacent transmission lines and At the interface, after mutual reflection and transmission, The forward voltage wave generated in and in T n-i The generated backward voltage wave They are respectively:

[0073] (17)

[0074] (18)

[0075] Therefore:

[0076] (19)

[0077] Equation (19) can be equivalently regarded as a traveling voltage wave. and subsequent voltage wave Both are adjacent transmission lines and There is no reflection at the interface, so it continues to propagate while maintaining its original amplitude and polarity.

[0078] Corollary 3 has been proven.

[0079] Based on Corollaries 1 to 3 above, the following analysis examines the situation when a square wave pulse with a pulse width of 2nτ is incident on the input transmission line. When the input port is reached, the wave process inside the pulse compression device of the present invention is as follows: As mentioned above, the wavefront of the square wave pulse has just propagated to the input transmission line. Transmission lines Low-resistance forming line The time at the interface is t=0, and the initial state of switch S is open.

[0080] (1) At t=0

[0081] A square wave pulse with amplitude V0 is incident on the low-resistivity forming line. and the input port of the stepped transmission line. Due to Z0 and Z n-1 The voltage divider effect injects low-resistivity forming lines The amplitude of the first-stage forward voltage wave is V0 / n.

[0082] (2) At time t=τ

[0083] Input transmission line Transmission lines Low-resistance forming line At the interface: no new voltage wave components were added.

[0084] Low resistance forming line Internally: The first-stage forward voltage wave propagates to switch S, forming a low-resistance line. The voltage across the entire segment is increased to V0 / n. Simultaneously, the first-stage forward voltage wave undergoes total reflection at switch S, generating a first-stage backward voltage wave with the same amplitude as V0 / n.

[0085] Inside a stepped transmission line: The square wavefront injected into the stepped transmission line propagates to the transmission line. and transmission lines At the interface, according to Corollary 1, the reflection will generate a first-stage backward voltage wave with an amplitude of -V0 / n.

[0086] (3) At time t=2τ

[0087] Input transmission line Transmission lines Low-resistance forming line At the interface: low resistance forming line The first-stage traveling voltage wave and the first-stage traveling voltage wave in the stepped transmission line propagate simultaneously to the input transmission line. Transmission lines Low-resistance forming line At the interface, they have the same amplitude but opposite polarity. According to the equivalent total internal reflection mechanism of Corollary 2, a second-order traveling voltage wave with an amplitude of V0 / n will be injected into the low-resistivity forming line at this time. A second-stage traveling voltage wave with an amplitude of -V0 / n is injected into the transmission line. No voltage wave is injected into the input transmission line. .

[0088] Low resistance forming line Internal: The first-stage forward voltage wave and the first-stage backward voltage wave fill the low-resistance forming line. The entire section will form a low-resistance line. The voltage across the entire section is increased to 2V0 / n.

[0089] Within a stepped transmission line: the injected square wavefront propagates to the transmission line. and transmission lines At the interface, according to Corollary 1, the reflection will generate a second-stage backward voltage wave with an amplitude of -V0 / n.

[0090] (4) At t=3τ

[0091] Input transmission line Transmission lines Low-resistance forming line At the interface: no new voltage wave components were added.

[0092] Low resistance forming line Internally: The second-stage forward voltage wave propagates to switch S, forming a low-resistance line. The voltage across the entire segment is increased to 3V0 / n. Simultaneously, the second-stage forward voltage wave undergoes total reflection at switch S, generating a second-stage backward voltage wave with the same amplitude as V0 / n.

[0093] Inside the stepped transmission line:

[0094] The second-stage forward voltage wave and the second-stage backward voltage wave propagate simultaneously to the transmission line. and transmission lines At the interface, their amplitudes are both -V0 / n. According to Corollary 3, it can be equivalently considered that they did not emit at this point, and continued to propagate while maintaining their original amplitudes and polarities.

[0095] Injected square wave wavefront propagates to transmission line and transmission lines At the interface, according to Corollary 1, the reflection will generate a third-order backward voltage wave with an amplitude of -V0 / n;

[0096] (5) At t=4τ

[0097] Input transmission line Transmission lines Low-resistance forming line At the interface: low resistance forming line The second-stage traveling voltage wave inside the inner transmission line and the second-stage traveling voltage wave inside the stepped transmission line propagate simultaneously to the input transmission line. Transmission lines Low-resistance forming line At the interface, they have the same amplitude but opposite polarity. According to the equivalent total internal reflection mechanism of Corollary 2, a third-order traveling voltage wave with an amplitude of V0 / n will be injected into the low-resistivity forming line at this time. A third-stage traveling voltage wave with an amplitude of -V0 / n is injected into the transmission line. No voltage wave is injected into the input transmission line. .

[0098] Low resistance forming line Inside: The first-stage forward voltage wave, the first-stage backward voltage wave, the second-stage forward voltage wave, and the second-stage backward voltage wave fill the low-resistance forming line. The entire section will form a low-resistance line. The voltage across the entire section is increased to 4V0 / n.

[0099] Inside the stepped transmission line:

[0100] The second-stage forward voltage wave and the third-stage backward voltage wave propagate simultaneously to the transmission line. Transmission lines At the interface, their amplitudes are both -V0 / n. According to Corollary 3, it can be equivalently considered that they did not emit at this point, and continued to propagate while maintaining their original amplitudes and polarities.

[0101] Injected square wave wavefront propagates to transmission line and transmission lines At the interface, according to Corollary 1, the reflection will generate a fourth-order backward voltage wave with an amplitude of -V0 / n.

[0102] (6) At t=5τ

[0103] Input transmission line Transmission lines Low-resistance forming line At the interface: no new voltage wave components were added.

[0104] Low resistance forming line Internally: The third-stage forward voltage wave propagates to switch S, forming a low-resistance line. The voltage across the entire segment is increased to 5V0 / n. Simultaneously, the third-stage forward voltage wave undergoes total reflection at switch S, generating a third-stage backward voltage wave with the same amplitude as V0 / n.

[0105] Inside the stepped transmission line:

[0106] The third-stage forward voltage wave and the third-stage backward voltage wave propagate simultaneously to the transmission line. and transmission lines At the interface, their amplitudes are both -V0 / n. According to Corollary 3, it can be equivalently considered that they did not emit at this point, and continued to propagate while maintaining their original amplitudes and polarities.

[0107] The second-stage forward voltage wave and the fourth-stage backward voltage wave propagate simultaneously to the transmission line. and transmission lines At the interface, their amplitudes are both -V0 / n. According to Corollary 3, it can be equivalently considered that they did not emit at this point, and continued to propagate while maintaining their original amplitudes and polarities.

[0108] Injected square wave wavefront propagates to transmission line and transmission lines At the interface, according to Corollary 1, the reflection will generate a fifth-order backward voltage wave with an amplitude of -V0 / n.

[0109] From the analysis in (1) to (6) above, it can be seen that the forward voltage wave and the backward voltage wave always arrive at the interface of adjacent transmission lines in the stepped transmission line in pairs at the same time, and their amplitudes and polarities are the same. Therefore, they can always be considered equivalently as not reflecting at the interface and continuing to propagate with their original amplitudes and polarities intact. Therefore, when analyzing the propagation process of the forward voltage wave and the backward voltage wave in the stepped transmission line, it is only necessary to consider their positions at a certain moment.

[0110] (7) At t=6τ

[0111] Input transmission line Transmission lines Low-resistance forming line At the interface: low resistance forming line The third-stage traveling voltage wave and the third-stage traveling voltage wave in the stepped transmission line propagate simultaneously to the input transmission line. Transmission lines Low-resistance forming line At the interface, they have the same amplitude but opposite polarity. According to the equivalent total internal reflection mechanism of Corollary 2, a fourth-order traveling voltage wave with an amplitude of V0 / n will be injected into the low-resistivity forming line at this time. A fourth-stage traveling voltage wave with an amplitude of -V0 / n is injected into the transmission line. No voltage wave is injected into the input transmission line. .

[0112] Low resistance forming line Inside: First-stage forward voltage wave, first-stage backward voltage wave, second-stage forward voltage wave, second-stage backward voltage wave, third-stage forward voltage wave, and third-stage backward voltage wave fill the low-resistance forming line. The entire section will form a low-resistance line. The voltage across the entire section is increased to 6V0 / n.

[0113] Inside the stepped transmission line:

[0114] The third-stage traveling voltage wave propagates to the transmission line. and transmission lines At the interface; the second-stage traveling voltage wave propagates to the transmission line. and transmission lines Interface;

[0115] The fifth-stage traveling voltage wave propagates to the transmission line. and transmission lines At the interface; the fourth-stage traveling voltage wave propagates to the transmission line. and transmission lines Interface;

[0116] Injected square wave wavefront propagates to transmission line and transmission lines At the interface, according to Corollary 1, the reflection will generate a sixth-order backward voltage wave with an amplitude of -V0 / n.

[0117] (8) Following the above method in sequence, we can obtain:

[0118] At time t=(n-1)τ, the injected square wavefront propagates to the transmission line within the stepped transmission line. At the short circuit point. At this time, the wavefront amplitude remains V0 / n, and after passing through the transmission line... After negative reflection at the short circuit, a (n-1)th stage backward voltage wave with an amplitude of -V0 / n is generated.

[0119] At time t=(2n-2)τ, the (n-1)th stage traveling voltage wave and low impedance formation line within the stepped transmission line The (n-1)th stage traveling voltage wave propagates simultaneously to the input transmission line. Transmission lines Low-resistance forming line At the interface, they have the same amplitude but opposite polarity. According to Corollary 2, at this point, an nth-stage forward voltage wave with an amplitude of V0 / n will be injected into the low-resistivity forming line. The nth-order traveling voltage wave with an amplitude of -V0 / n is injected into the transmission line. .

[0120] At time t=(2n-1)τ, the original square wave pulse continues to be injected, and the remaining tail wave pulse width is τ. Low-resistance forming line. The entire segment is simultaneously filled with n forward voltage waves and n-1 backward voltage waves, forming a low-resistance line. The voltage across the entire segment is increased to (2n-1) (V0 / n).

[0121] At time t=2nτ, the injected square wave ends, and the low-resistance line is formed. The entire segment simultaneously contains n forward voltage waves and n backward voltage waves, forming a low-resistance line. The voltage across the entire section is increased to 2n(V0 / n) = 2V0.

[0122] From the analysis process of (1) to (8) above, it can be seen that with the injection of square wave pulses, low resistance forming lines New forward and backward voltage waves are alternately added internally, while the input transmission line... No voltage wave was injected internally. Correspondingly, from t=0 to t=2nτ, a low-resistance line was formed. The internal voltage increases periodically with a period of τ, and the increment value per period is V0 / n.

[0123] The following calculation shows the low-resistance formation line at time t=2nτ. Energy stored in the segment Low-resistance forming line Energy stored in the segment Including forward voltage wave energy and the energy of the traveling voltage wave :

[0124] (20)

[0125] Comparing equations (3) and (20), it can be seen that at t=2nτ, the low-resistance formation line... The segment received all the energy of the original injected square wave pulse. This means that the energy inside the stepped transmission line is zero at this moment.

[0126] In the above wave process analysis, only the low-resistivity formation line was quantitatively calculated. The voltage wave accumulation process in the intermediate stage was not considered in the context of the stepped transmission line. In fact, by analyzing the voltage wave accumulation process within the stepped transmission line stage by stage, it can be found that when t≥(n+1)τ, as the second-stage advancing voltage wave propagates to the transmission line... At the short circuit point, a negative reflection occurs, and the energy clearing process begins within the stepped transmission line:

[0127] At time t=(n+2)τ, the transmission line Internal energy depleted;

[0128] At time t=(n+3)τ, the transmission line Internal energy depleted;

[0129] ...

[0130] At time t=2nτ, the transmission line Internal energy is depleted.

[0131] That is, at time t=2nτ, all the energy inside the stepped transmission line is emptied. Because of the input transmission line... Since no energy is injected internally, at time t=2nτ, all the energy of the original injected square wave pulse can only exist entirely within the low-resistivity forming line. Within the segment. This conclusion is consistent with equation (20).

[0132] Low resistance forming line The state of the segment at t=2nτ is not stable. When t>2nτ, the reverse wave process begins, and a low-resistivity line forms. The energy accumulated in the segment will begin to be transferred to the input transmission line. Release the stepped transmission line.

[0133] Although a low-resistance line forms at t=2nτ The energy is highest within this segment, but switch S is not suitable to be turned on at that moment. This is because if switch S is turned on at t=2nτ, then a low-resistance forming line... To load R L During discharge, a low-resistance line is formed. To the input transmission line The reverse wave process of the discharge from the stepped transmission line is also underway, causing the load R to... L Not all energy can be obtained.

[0134] In order to release all the energy to the load R L The switch S should be turned on at time t = (2n-1)τ. The subsequent wave process is as follows:

[0135] At time t=(2n-1)τ, switch S is turned on, and a low-resistance line is formed. The n forward voltage waves (total amplitude V0) existing within the segment begin to propagate towards the load R. L Propagation; Since the mechanism for generating a backward voltage wave through reflection at switch S no longer exists, n-1 backward voltage waves are truncated, resulting in a falling edge, and the falling edge forms a low-resistance line. Input transmission line Transmission lines Interface propagation;

[0136] (2n-1)τ<t<2nτ, low resistance forming line Within the segment, n traveling voltage waves continuously propagate towards the load R. L Propagation; because the falling edge of the subsequent voltage wave has not yet propagated to the low-resistance forming line. Input transmission line Transmission lines Interface, therefore low resistance forming line Input transmission line Transmission lines The conditions for generating forward voltage waves at the interface have not changed, and forward voltage waves continue to be generated.

[0137] At time t=2nτ, on the input transmission line Transmission lines Low-resistance forming line At the interface, a low-resistivity line is formed. Internal rear-traveling voltage wave, transmission line The internal voltage wave and the original injected square wave pulse disappear simultaneously, and the energy within the stepped transmission line is cleared. This is due to the low-resistance forming line described in Corollary 2. The internal forward voltage wave generation mechanism no longer exists, therefore low resistance is formed. The inner forward voltage wave exhibits a falling edge;

[0138] At time 2nτ<t<(2n+1)τ, as the low-resistivity formation line... Sectional load R L As discharge proceeds, the falling edge of the traveling voltage wave forms from the low-resistance line. Input transmission line Transmission lines The interface faces the load R L spread.

[0139] At time t=(2n+1)τ, the falling edge of the traveling voltage wave propagates to R. L Above, the forward voltage wave disappears, and a low-resistance line is formed. Internal energy is depleted.

[0140] From the above wave process, it can be seen that when switch S is turned on at time t=(2n-1)τ, the load R L The output pulse with a pulse width of 2τ and an amplitude of V0 can be obtained, and the output pulse power is... and total energy for:

[0141] (twenty one)

[0142] (twenty two)

[0143] Equations (21) and (22) show that, compared with the input pulse (i.e., the original square wave pulse), R L The output pulse power is increased by n times, the pulse width is shortened to 1 / n, and the energy efficiency is 100%.

[0144] The pulse compression device of this invention also has a feature: from t=0 to t=2nτ, a low-resistance forming line... The internal voltage increases periodically with a period of τ, and the increase value per period is V0 / n, which forms the low resistance line. The internal voltage amplitude exhibits a step-like increase with constant amplitude. In contrast, existing pulse compression devices ( Figure 1 Low and medium resistance forming line Although the internal voltage amplitude also increases in steps, the amplitude of each step decreases, indicating a low-resistance forming line. The internal voltage amplitude growth shows a saturation trend. This means that, compared with existing pulse compression devices ( Figure 1 Compared to existing pulse compression devices, the switch S in this invention experiences a higher rate of voltage rise before conduction, which helps reduce switch bounce and improve switch stability. Furthermore, in practical engineering applications, because the switch S in this invention exhibits low bounce, it eliminates the need for existing pulse compression devices. Figure 1 This significantly advances the switching operating point, resulting in high input pulse width utilization efficiency. These are two other advantages of the pulse compression device of the present invention.

[0145] The transmission lines in the pulse compression device of this invention can be designed as various transmission line structures such as coaxial lines, microstrip lines, and parallel planar lines. Designing the transmission lines as coaxial lines is beneficial for increasing the system's power capacity. Similarly, the switch S can be of various forms such as a gas switch, a solid-state switch, or a liquid switch. Selecting a gas switch as the switch S is beneficial for achieving high power capacity and high recoverability.

[0146] This invention provides a design embodiment of a second-order pulse compression device for compressing the output pulse of an existing high-power pulse source by a factor of two. The existing high-power pulse source has an output pulse power of 6GW, a pulse width of 20ns, and an output impedance of 24Ω. To achieve high power capacity, the second-order pulse compression device of this embodiment is designed as a coaxial structure, such as... Figure 3 As shown. Among them, For input transmission lines, To form a low-resistance line, This is a stepped transmission line with a short circuit at the end, and S is a gas switch. This is the load (output transmission line). For a second-order pulse compressor, the order of its internal stepped transmission line is 1, therefore... It consists of only one transmission line in form. During experimental testing, the output transmission line... The output port can be connected to a water resistor to absorb the output pulse energy.

[0147] The electrical parameters of the coaxial second-order pulse compression device in this embodiment are as follows: (1) The impedance Z2 = 24Ω. The propagation time of electromagnetic waves is not a critical parameter and can be set according to the principle of convenient installation; (2) The impedance is The impedance is 1 / 2, and the electromagnetic wave propagation time should be 1 / 4 of the input pulse width, i.e., Z0=12Ω, τ=5ns; (3) Both impedance and electromagnetic wave propagation time are related to The same, i.e., Z1=12Ω, τ=5ns; (4) The impedance should be consistent with Same, ZL =12Ω. The electromagnetic wave propagation time is not a key parameter and can be set according to the principle of easy installation and easy measurement of the output pulse waveform; (5) The conduction time of S is t=15ns (i.e. t=3τ).

[0148] In this embodiment, the gas switch S of the coaxial second-order pulse compression device uses 4 MPa nitrogen as the insulating medium. , , , Transformer oil is used as the insulating medium.

[0149] The coaxial second-order pulse compression device in this embodiment has no special requirements in terms of high-voltage insulation design and mechanical design. It can directly refer to the relevant design methods of conventional coaxial pulse power systems (such as high-power pulse sources based on single-cylinder pulse forming lines, high-power pulse sources based on Blumlein forming lines, etc.), such as using nylon insulators to support the internal coaxial conductors, using nylon insulating plates for oil sealing and oil-gas isolation, and chamfering the metal edges, etc., which will not be elaborated further. The main structural parameters of this coaxial second-order pulse compression device can be designed as follows: r1=55mm; r2=73mm; r3=100mm; Δr2=2mm; Δr3=2mm; l1=1000mm; l2=200mm; l3=1000mm; Δl1=25mm; l s =10mm.

[0150] This embodiment describes a coaxial second-order pulse compression device, with its input port connected to an existing pulse source and its output port connected to a water resistance load. Experimental tests were conducted. Figure 4 Experimental waveforms are presented. It can be seen that an existing high-power pulse source outputs a pulse power of 6 GW and a pulse width of 20 ns. After compression by the coaxial second-order pulse compression device of this embodiment, the output pulse power is 11.5 GW and the pulse width is 10 ns. Calculations show that the actual power gain of the coaxial second-order pulse compression device of this embodiment reaches 1.92, and the energy efficiency reaches 95.8%. Analysis shows that the small amount of energy loss is mainly caused by the conduction resistance loss of the gas switch. These experimental results demonstrate that the pulse compression device of this invention achieves high-energy-efficiency pulse compression.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A pulse compression device, characterized in that: Including input transmission lines Stepped transmission lines, low-resistance forming lines Switch S and load R L n is the order, n≥2; The stepped transmission line includes n-1 segments of transmission lines of equal electrical length connected sequentially. Transmission lines ... transmission lines and transmission lines ; The low-resistance forming line The electrical length is the same as the electrical length of a single segment of transmission line in a stepped transmission line; The input transmission line The input port is used to connect to an external high-power pulse source; The transmission line The input port and low impedance form a line After the input ports are connected in series, connect the input transmission line. The output port; The switch S and the load R L One end is connected in series, and the other end is connected to a low-resistance forming wire. The output port; The transmission line Short-circuit the output port; The input transmission line Forming lines with low resistance The impedance ratio is n, and the transmission line Transmission lines ... transmission lines and transmission lines Forming lines with low resistance The impedance ratios are n(n-1) / n, (n-1)(n-2) / n, ..., 3·2 / n, 2·1 / n.

2. The pulse compression device according to claim 1, characterized in that, The low-resistance forming line The electrical length is determined as follows: Pulse wave forming line at low resistance The propagation time τ is 1 / 2n of the pulse width.

3. The pulse compression device according to claim 2, characterized in that, The closing time of the switch S is determined according to the following method: Define the wavefront of a pulse wave propagating to the input transmission line. Transmission lines and transmission lines If the time at the interface is t=0, then the closing time of switch S is t=(2n-1)τ.

4. The pulse compression device according to claim 3, characterized in that: The input transmission line Stepped transmission lines and low-resistance forming lines It can be a coaxial line, microstrip line, or parallel plate line.

5. A pulse compression device according to claim 4, characterized in that: The switch S is a gas switch, a solid switch, or a liquid switch.

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