Pulse shaping circuit-based steep edge pulse energy shaping method

Abstract

The invention relates to the technical field of steep-edge pulse forming of pulse forming circuits, in particular to a steep-edge pulse energy forming method based on a pulse forming circuit, which comprises the following steps: charging an energy storage capacitor bank in a preset charging period, and performing initial gating on a forming network formed by PFN sections and Blumlein transmission line sections and an impedance gradient matching network; when the charging voltage reaches a target value, a shaping switch is triggered to output a test pulse, an incident component and a reflection component are obtained through an output sampling branch, and a reflection characteristic quantity is generated; the reflection characteristic quantity executes gating updating on matching network segment impedance configuration and forming network segment combination according to a minimum reflection criterion, and a retest pulse is triggered to obtain a retest reflection characteristic quantity; and when the remeasured reflection characteristic quantity is smaller than or equal to the reflection judgment threshold value, triggering working pulse output, and obtaining a steep edge pulse energy forming result at the load end. According to the invention, impedance matching consistency and waveform stability are improved through reflection quantity closed-loop gating.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steep pulse shaping of pulse forming circuit, and particularly relates to a steep pulse energy shaping method based on a pulse forming circuit. BACKGROUND

[0002] With the development of high-voltage pulse power supply, high-speed power device and electromagnetic energy modulation technology, the pulse forming circuit continues to evolve in the direction of high repetition rate energy release, transient excitation and load end waveform consistency control; the existing pulse technology usually adopts an energy storage capacitor group as an energy source, uses a fast forming switch as a gating device, and restrains the rising edge, amplitude flatness and effective pulse width of the output pulse through a pulse forming network; in terms of the forming network, the pulse forming network (PFN) composed of multiple inductance and capacitance segments has the characteristics of discrete segment configuration and easy extension of energy level; the Blumlein forming structure based on the equivalent characteristic impedance of the transmission line has the characteristics of good flat top holding ability and strong waveform symmetry, so the PFN segments and the Blumlein transmission line segments are combined, and the segments are switched and configured through a gating switch array, which gradually becomes a circuit scheme that takes into account high voltage bearing and waveform adjustment; at the same time, in order to reduce the reflection and ringing caused by the equivalent impedance of the connecting conductor, the interface and the load end, a matching network or an absorption branch is usually introduced in the prior art, such as an impedance gradual matching network that improves energy coupling and echo attenuation through segmented characteristic impedance transition.

[0003] However, after the existing pulse forming circuit is connected with the forming network and the load end, there are still problems of reflection and echo caused by impedance mismatch: on the one hand, the equivalent output impedance of the forming network and the equivalent impedance of the load end deviate in different working states, and after superimposing the parasitic inductance, the parasitic capacitance and the switching transient characteristics of the wiring, the incident wave and the reflected wave are easily superimposed, resulting in flat top collapse, amplitude fluctuation, front overshoot and tail drag, thereby causing the decrease of the effective pulse width and the dispersion of the energy density; on the other hand, the fixed parameter matching network cannot cover the change range of the equivalent impedance of the load end, and when the matching is insufficient, the echo is intensified, and when the matching is excessive, the damping introduces additional loss and sacrifices the steepness characteristics, so that the reflection suppression, the steepness maintenance and the energy utilization rate are difficult to be considered; in addition, the existing segment selection is usually based on offline design and experience setting, and lacks gating triggering and retest determination mechanism based on circuit sampling feedback, so that the segment configuration cannot quickly converge to a low reflection state after switching the energy level or replacing the load, and the predictability and consistency of the output waveform are insufficient.

[0004] In view of the problem that the existing pulse shaping network has impedance mismatch when connected with a load end, resulting in reflection and echo, and then causing the flatness of the square top to decrease and the effective pulse width to shorten, the present application is proposed; therefore, the problem to be solved by the present application is how to introduce the segmented gating of the impedance gradual matching network on the basis of the pulse shaping circuit composed of the energy storage capacitor group, the shaping switch, the PFN segment and the Blumlein transmission line segment, and establish the gating update and retest determination gating process under the minimum reflection criterion based on the reflection characteristic quantity of the test pulse, so that the load end obtains the steep pulse energy shaping result with flat amplitude. SUMMARY

[0005] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments, and some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0006] In view of the above-mentioned existing problems, the present application is proposed.

[0007] To solve the above technical problems, the present application provides the following technical solutions.

[0008] In a first aspect, the present application provides a steep pulse energy shaping method based on a pulse shaping circuit, comprising: charging an energy storage capacitor group in the pulse shaping circuit within a preset charging period, and initially gating a shaping network composed of PFN segments and Blumlein transmission line segments and an impedance gradual matching network;

[0009] After the charging voltage of the energy storage capacitor group reaches a target value, a test pulse is triggered to be output by the shaping switch, and a reflection characteristic quantity of the test pulse is obtained at an output sampling branch;

[0010] The segmented impedance configuration of the impedance gradual matching network and the segment combination of the shaping network are gated and updated according to the reflection characteristic quantity using the minimum reflection criterion, and after completion, a retest test pulse is triggered to be output by the shaping switch, and a retest reflection characteristic quantity of the retest test pulse is obtained;

[0011] When the retest reflection characteristic quantity is less than or equal to a reflection determination threshold, a working pulse is triggered to be output by the shaping switch, and a steep pulse energy shaping result is obtained at a load end connected to the output end of the pulse shaping circuit.

[0012] In a second aspect, the present application provides a computer device, comprising:

[0013] One or more processors;

[0014] a memory storing instructions operable that, when executed by the one or more processors, cause the one or more processors to perform operations comprising the flow of the aforementioned pulse shaping circuit based steep front pulse energy shaping method.

[0015] In a third aspect, the present application provides a computer readable medium storing software comprising instructions executable by one or more computers that, through such execution, cause the one or more computers to perform operations comprising the flow of the aforementioned pulse shaping circuit based steep front pulse energy shaping method.

[0016] The present application has the following beneficial effects: The present application charges the energy storage capacitor bank and initially triggers the PFN section, Blumlein transmission line section and impedance gradient matching network to form a shaping topology matching the target energy level, reduces the waveform uncertainty of the first output, and improves the consistency of the shaping starting point. The present application obtains the quantitative representation of the deviation of the shaping network and the impedance at the load end by outputting a test pulse and extracting reflection characteristics in the output sampling branch, reduces the dependence on empirical parameter adjustment, and suppresses the square top collapse caused by echo and ringing by updating and retesting the segmented impedance configuration and section combination according to the minimum reflection criterion, thereby improving the flatness and effective pulse width. The present application triggers the output of the working pulse when the retested reflection characteristics meet the determination threshold, obtains the steep front pulse energy shaping result at the load end, and improves the energy utilization rate and the output waveform repeatability. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor. Among them:

[0018] Figure 1 The flowchart of the pulse shaping circuit based steep front pulse energy shaping method shown in the present application;

[0019] Figure 2 The flowchart of the triggering update method shown in the present application;

[0020] Figure 3 The schematic diagram of the load end voltage waveform and key index annotation shown in the present application;

[0021] Figure 4 The schematic diagram of the cumulative energy curve and total energy annotation shown in the present application;

[0022] Figure 5 The schematic diagram of the reflection characteristic quantity changing with the number of triggering iterations shown in the present application. DETAILED DESCRIPTION

[0023] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0024] Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0025] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in other manners different from those described herein without departing from the scope of the present application. Those skilled in the art can make similar modifications and improvements without departing from the scope of the present application, and therefore the present application is not limited to the specific embodiments disclosed below.

[0026] According to the embodiments of the present application, in combination with the flow chart shown in the figure, a steep pulse energy shaping method based on a pulse shaping circuit specifically includes the following steps: Figure 1

[0027] S1, in a preset charging period, the energy storage capacitor bank in the pulse shaping circuit is charged, and the shaping network composed of PFN segments and Blumlein transmission line segments and the impedance gradient matching network are initially gated. It should be noted that in this step:

[0028] S1.1, at the beginning of the preset charging period, the energy storage capacitor bank in the pulse shaping circuit and the charging power source are connected through the charging switch to form a charging loop.

[0029] In a preferred embodiment, the pulse shaping circuit includes a charging power source, a charging switch, an energy storage capacitor bank, a charging current limiting branch, a discharge isolation branch and a voltage sampling branch.

[0030] In a preferred embodiment, the preset charging period takes the cycle timing trigger of the control unit as the starting basis: when the cycle timing arrives, the control unit first maintains the shaping switch in the open state, and maintains the PFN segment gating switch, the Blumlein gating switch and the matching network gating switch in the open state; then the control unit outputs the gate drive to the charging switch, so that the charging power source forms a closed loop with the energy storage capacitor bank through the charging current limiting branch, and the energy storage capacitor bank starts to accumulate electric charge.

[0031] As an example, the charging current limiting branch is in the form of resistance-inductance series, wherein the inductance value is determined according to the switching transient current rise rate constraint; the discharge isolation branch can be a combination of unidirectional isolation devices and damping resistors to suppress the sharp peaks coupled back from the shaping network side during the charging phase.​

[0032] The preset charging period in the embodiment can be set according to a target pulse repetition frequency, for example, when the target repetition frequency is 100 Hz, the preset charging period is 10 ms; when the target repetition frequency is 50 Hz, the preset charging period is 20 ms; the embodiment does not have a unique limitation requirement.

[0033] S1.2, during the conduction of the charging circuit, the terminal voltage of the energy storage capacitor bank is collected as the charging voltage, and the nominal impedance level of the load connected to the output end of the pulse shaping circuit is read.

[0034] It should be noted that the conduction of the charging circuit includes: the charging switch is in the conduction state, a continuous current channel is formed between the output end of the charging power supply and the two ends of the energy storage capacitor bank, and there is no open circuit fault alarm in the charging current limiting branch.

[0035] Further, the control unit periodically samples the terminal voltage of the energy storage capacitor bank through the voltage sampling branch during the conduction of the charging circuit. The voltage sampling branch can be composed of a high-voltage voltage divider and an isolation sampling module: the output of the voltage divider is sent to the analog-to-digital conversion channel after isolation amplification; the sampling period is 50 μs; in order to suppress the influence of switch spikes on sampling, a first-order low-pass network is connected in series at the front end of the isolation sampling module, and consistency verification is performed on the control unit side for three consecutive samplings, and the verification rule includes: the difference between the adjacent two times does not exceed 0.3% of the voltage converted by the voltage divider, which is considered as passing the verification.

[0036] In order to avoid introducing additional high-energy tests, the embodiment preferably adopts a configuration memory reporting mode: after power-on self-test, the load end sends the impedance position code to the control unit through the isolation communication interface; the control unit maps the position code to the nominal impedance level of the load; wherein the nominal impedance level of the load is divided according to commonly used loads, for example, 25 Ω, 50 Ω, 75 Ω, and 100 Ω.

[0037] S1.3, according to the charging voltage and the nominal impedance level of the load, determine the initial segment identifier in the shaping segment selection table, and close the PFN selection switch and the Blumlein selection switch according to the initial segment identifier to complete the initial selection of the shaping network composed of PFN segments and Blumlein transmission line segments.

[0038] Specifically, the shaping segment selection table is a segment corresponding relationship table obtained offline for different charging voltage levels and nominal impedance levels of the load. The table entries of the shaping segment selection table are stored in the form of initial segment identifiers, wherein the initial segment identifier includes PFN segment selection identifier, Blumlein transmission line segment selection identifier, and segment selection identifier of impedance gradual matching network.

[0039] In a preferred embodiment, after obtaining the charging voltage, the control unit maps the charging voltage to a charging voltage level code (e.g. 18 kV~20 kV is mapped to level code V3, 20 kV~22 kV is mapped to V4); meanwhile maps the read load nominal impedance level to an impedance level code (e.g. 50 Ω is mapped to Z2); then retrieves in the shaped segment gating table with the charging voltage level code-impedance level code as index, reads out the initial segment identification in the corresponding table entry; the control unit issues the gating switch closing instruction in the order of PFN first and Blumlein second, and inserts a fixed delay (e.g. 5 ms) between adjacent closings to stabilize the switch state and complete the state readback; when the PFN and Blumlein gating state readback are consistent, the initial segment identification is recorded as effective.

[0040] As an example, PFN segment gating identification: PFN is composed of 8 segments in series, the identification is represented as PFN-1...PFN-8 to indicate which segment is closed; for example, PFN-5 indicates that the gating switch is closed to the 5th segment, and the rest of the segments are open.

[0041] As an example, Blumlein transmission line segment gating identification: Blumlein is composed of 3 switchable segments, the identification is represented as BL-1...BL-3; for example, BL-2 indicates that the gating switch of the 2nd segment is closed.

[0042] As an example, impedance gradual matching network segment gating identification: the matching network is composed of 4 impedance gradual units, the identification is represented as MN-1...MN-4 to indicate which segment is connected; for example, MN-3 indicates that the matching network is connected to the 3rd segment, forming a preset segmented impedance configuration.

[0043] S1.4, after the initial gating of the shaped network is completed, the matching network gating switch is closed according to the initial segment identification to connect the impedance gradual matching network, completing the initial gating of the impedance gradual matching network.

[0044] In a preferred embodiment, the matching network gating switch is composed of multiple high-voltage relays, and the control unit reads the impedance gradual matching network segment gating identification in the initial segment identification after confirming that the PFN and Blumlein gating state readback are consistent, and outputs a closing instruction to the corresponding matching network gating switch, so that the first several segments of the matching network are connected to the output channel according to the preset topology; to avoid the switching transient affecting the voltage of the energy storage capacitor bank, the matching network gating can be arranged to be performed when the charging voltage is close to the target charging voltage and the charging voltage change rate is lower than a threshold value; the threshold value is that the charging voltage increment of three consecutive sampling points is less than 0.2% of the full scale.

[0045] It should be noted that the PFN section, the Blumlein transmission line section and the impedance gradient matching network are all switchable structures, and different combinations correspond to different equivalent output impedances, equivalent transmission delays and equivalent waveform shaping capabilities; the charging stage is to complete the initial gating, and the reason is that the charging voltage and the nominal impedance level of the load determine the energy release intensity and the impedance mismatch risk during subsequent discharge, and the initial section identifier is obtained according to the two, and then the matching network is connected, so that the reflection amount can be controlled in a small range during the first test pulse stage, and the overvoltage and waveform distortion caused by reflection are reduced.

[0046] Preferably, the initial section identifier is placed in front of the available combination obtained by offline calibration to the online process, so that the trial range of the first test pulse converges and the number of repeated switching is reduced; the impedance gradient matching network is pre-connected in the charging stage, so that the equivalent impedance of the load seen by the shaping network is closer to the expected value, so that the subsequent rising edge and square top are more likely to fall into the target interval.

[0047] S2, after the charging voltage of the energy storage capacitor bank reaches the target value, the forming switch is triggered to output a test pulse, and the reflection characteristic quantity of the test pulse is obtained in the output sampling branch. It should be noted that the present step is:

[0048] S2.1, during the preset charging period, the voltage of the energy storage capacitor bank is sampled by the voltage sampling branch to obtain the charging voltage, and the charging voltage is compared with the target charging voltage.

[0049] Specifically, the method of comparing the charging voltage with the target charging voltage includes:

[0050] When the absolute value of the difference is less than or equal to the voltage tolerance threshold (which is 1%~2% of the target charging voltage), the charging voltage of the energy storage capacitor bank reaches the target value;

[0051] When the absolute value of the difference is greater than the voltage tolerance threshold, the charging circuit is maintained to be turned on and the energy storage capacitor bank is continuously charged until the absolute value of the difference is less than or equal to the voltage tolerance threshold.

[0052] In a preferred embodiment, the control unit continuously reads the voltage sampling branch output during the preset charging period, and the voltage sampling branch output is converted to the charging voltage; the target charging voltage is given by the working gear, for example, for a 50 Ω load and a target pulse energy gear, the target charging voltage is 20 kV, and the voltage tolerance threshold is 200 V.

[0053] S2.2 When the charging voltage of the energy storage capacitor bank reaches the target value, a test trigger signal is output to the test trigger control terminal, and the forming switch is closed within the calibrated pulse width of the test trigger signal (the equivalent discharge duration is shorter than the working pulse to reduce the energy of a single test and suppress heat accumulation), so that the forming network and the impedance gradient matching network release a test pulse to the load terminal.

[0054] In a preferred embodiment, the test trigger control terminal and the forming switch are isolated trigger links. After the control unit determines that the charging voltage has reached the target value, it first outputs a trigger request to the test trigger control terminal. The test trigger control terminal then outputs a test trigger signal to the driver of the forming switch. The forming switch can be a gas switch, a magnetic switch, or a solid-state switch array. After receiving the test trigger signal, the corresponding driver controls the conduction duration of the forming switch according to the calibrated pulse width, so that the forming network and the matching network release a low duty cycle test pulse to the load.

[0055] For example, when the equivalent width of the working pulse is 200 ns, the calibration pulse width of the test trigger signal can be taken as 50 ns to 80 ns.

[0056] S2.3 During the test pulse output, the incident amplitude and the reflected amplitude are obtained by the output sampling branch respectively, and the reflection characteristic quantity is generated based on the amplitude ratio of the incident amplitude and the reflected amplitude.

[0057] In this embodiment, the output sampling branch is set on the transmission channel between the output end of the pulse shaping circuit and the load end, and separates the incident component propagating along the load direction from the reflected component reflected back from the load end. The separated output is isolated and attenuated before entering the high-speed sampling module.

[0058] Furthermore, the control unit uses the test trigger time as the time reference and takes the peak values ​​of the incident component waveform and the reflection component waveform within a preset sampling window (such as 150ns after triggering) as the incident amplitude and the reflection amplitude.

[0059] As an example, the mathematical expression for the reflection feature is as follows: ; in, It is a reflection characteristic quantity; This refers to the reflection amplitude read within a preset sampling window on the reflection component channel of the output sampling branch; This refers to the incident amplitude value read within a preset sampling window on the incident component channel of the output sampling branch; This is used to perform the absolute value operation on the amplitude.

[0060] Preferably, the reflection characteristics are sensitive to impedance mismatch, and the observability of impedance mismatch is related to the incident amplitude. When the charging voltage does not reach the target value, the insufficient incident amplitude will lead to a decrease in the resolution of the reflection characteristics, making the judgment basis for subsequent gating updates unstable. By testing the trigger link to output a low duty cycle test pulse and extracting the reflection characteristics, the equivalent mismatch degree of the forming network, matching network, and load channel can be obtained without introducing additional external measurement equipment, which can be used for subsequent segmented gating updates. Compared with the scheme of passively observing the waveform at the load end only during the working pulse stage, this embodiment introduces a priori detection link of test pulse and reflection characteristics, so that the gating update can complete the convergence judgment before the working pulse, reducing the risk of overshoot and distortion caused by the working pulse directly hitting the mismatched load.

[0061] S3. Based on the reflection characteristic quantity, the segmented impedance configuration of the impedance gradient matching network and the segment combination of the shaping network are updated using the minimum reflection criterion. After completion, the shaping switch is triggered to output a retest test pulse, and the retest reflection characteristic quantity of the retest test pulse is obtained. (Refer to...) Figure 2 In this step, it is important to note that:

[0062] S3.1. Based on the reflection characteristic quantity, the gating control unit is triggered to enter the gating update process and obtain the matching segment identifier and shaping segment identifier of the current gating. The matching segment identifier is the segmented impedance configuration of the impedance gradient matching network, and the shaping segment identifier is the segment combination of the shaping network.

[0063] In a preferred embodiment, after obtaining the reflection characteristic, the control unit compares the reflection characteristic with a preset reflection judgment threshold. When the reflection characteristic is greater than the reflection judgment threshold, the control unit enters the gating update process. After entering the process, the control unit first reads the effective initial segment identifier from the current gating status register, and uses the impedance gradient matching network segment gating identifier as the current matching segment identifier, and uses the combination of the PFN segment gating identifier and the Blumlein transmission line segment gating identifier as the current forming segment identifier. At the same time, the control unit reads the status readback bit of each gating switch. If the readback is inconsistent with the register, an anomaly is recorded and the update is limited to only one switch before retesting, so as to avoid the uncertainty introduced by multiple switches.

[0064] S3.2 Output candidate selection instructions according to the single-variable switching rules, wherein the single-variable switching rules include: when keeping the forming segment identifier unchanged, only switch the matching segment identifier between adjacent segments to obtain the first candidate group; and when keeping the matching segment identifier unchanged, only switch the forming segment identifier between adjacent segment combinations to obtain the second candidate group.

[0065] It should be noted that the single-variable switching rule in this embodiment comes from the sensitivity assessment of adjacent segments during the offline calibration stage: under the same forming segment identifier, the effect of switching of adjacent matching network segments on the reflection feature quantity is monotonically or nearly monotonically changing; under the same matching segment identifier, the combined switching of adjacent forming segments has a more significant effect on the rising edge and square top indices; based on this rule, the online update preferably adopts a strategy of switching only one variable per round, so as to attribute the change of reflection feature quantity to a single switching action.

[0066] For example, if the current initial segment identifier is PFN-5 / BL-2 / MN-3, the first candidate group can be constructed by changing the adjacent segments of the matching segment identifier while keeping the forming segment identifier unchanged, thus forming two candidates, MN-2 and MN-4. Their initial segment identifiers are PFN-5 / BL-2 / MN-2 and PFN-5 / BL-2 / MN-4, respectively. The second candidate group can be constructed by changing the adjacent combinations of the forming segment identifier while keeping the matching segment identifier unchanged. For example, if the adjacent PFN segments are PFN-4 and PFN-6, and the adjacent Blumlein segments are BL-1 and BL-3, then candidates can be generated under the premise that the constraint is changed only when PFN or only Blumlein is changed each time, such as PFN-4 / BL-2 / MN-3, PFN-6 / BL-2 / MN-3, PFN-5 / BL-1 / MN-3, and PFN-5 / BL-3 / MN-3.

[0067] S3.3 Trigger test pulses for the first candidate group and the second candidate group one by one and generate corresponding candidate reflection characteristic quantities. Use the smallest amplitude of the candidate reflection characteristic quantity as the minimum reflection criterion to determine the target candidate gating instruction.

[0068] Specifically, the control unit executes the first and second candidate groups sequentially: first, it sends a candidate gating instruction to the gating control unit; after the gating status is consistent, it triggers the forming switch to output a test pulse; then, it obtains the candidate reflection characteristic quantity corresponding to the candidate according to S2.3, and binds the candidate reflection characteristic quantity with the candidate identifier and stores it in the candidate result table; for the same candidate, in order to reduce the influence of random fluctuations, two test pulses can be output continuously and the larger of the candidate reflection characteristic quantities can be taken as a conservative value; when the difference between the two exceeds 20%, the candidate is marked as an unstable candidate and eliminated.

[0069] Furthermore, the minimum reflection criterion in this embodiment is as follows: after eliminating unstable candidates, the remaining candidates are sorted in ascending order of candidate reflection feature quantity, and the candidate gating instruction corresponding to the smallest one is taken as the target candidate gating instruction; when there are ties for the smallest one, the candidate that only switches the matching segment identifier is selected first, so as to reduce the disturbance to the pulse width and rising edge.

[0070] It should be noted that the control unit in this embodiment is the gate control body of the pulse shaping circuit, and the gating control unit is the gating execution module driven by the control unit. The gating execution module is electrically connected to the PFN segment gating switch, the Blumlein gating switch and the matching network gating switch to perform segment switching and status readback.

[0071] S3.4 Update the matching segment identifier and shaping segment identifier according to the target candidate gating instruction to complete the gating update of the segmented impedance configuration of the impedance gradient matching network and the segment combination of the shaping network.

[0072] In a preferred embodiment, the control unit sends the target candidate gating instruction to the gating control unit. After the gating control unit completes the switch switching, it reads back the final state. The control unit writes the readback result into the current initial segment identifier register and simultaneously writes the update sequence number, reflection feature quantity, and trigger timestamp. When the reflection feature quantity is still not up to standard in subsequent retests, the next round of updates continues to construct adjacent candidates starting from the current initial segment identifier in the register, thereby forming a continuous and traceable gating update link.

[0073] It should be noted that both the impedance gradient matching network and the shaping network are segmented and switchable structures. Changes in the equivalent impedance at the load end and the parasitic parameters of the transmission channel will be directly reflected in the changes in the reflection characteristic quantity. In this embodiment, the purpose of gating and updating based on the minimum reflection criterion is that when the reflection characteristic quantity decreases, the coupling efficiency of the incident energy to the load is improved, the overshoot and ringing caused by the reflection circuit are reduced, and the flatness of the load end and the rising edge can obtain more stable results. The single-variable switching rule makes the correspondence between each round of switching action and the change in the reflection characteristic quantity clearer.

[0074] In an example gating update process, the reflection feature quantity changes with the iteration rounds as follows: Figure 5 As shown, the reflection characteristic gradually decreases and tends to be near the threshold.

[0075] S4. When the re-measured reflection characteristic is less than or equal to the reflection judgment threshold, the shaping switch is triggered to output a working pulse, and a steep-edge pulse energy shaping result is obtained at the load terminal connected to the output terminal of the pulse shaping circuit. It should be noted that the following points are important in this step:

[0076] S4.1 When the retested reflection characteristic quantity is greater than the reflection judgment threshold (e.g., 0.10), output the gating update instruction and return to step S3 to execute the next round of gating update.

[0077] S4.2 When the re-measured reflection characteristic quantity is less than or equal to the reflection judgment threshold, the shaping switch is triggered to output a working pulse, and a steep-edge pulse energy shaping result is obtained at the load terminal connected to the output terminal of the pulse shaping circuit (e.g., Figure 3 (As shown).

[0078] Specifically, the load terminal connected to the output terminal of the pulse shaping circuit receives the output working pulse. During the output of the working pulse, the load terminal voltage waveform and load terminal current waveform of the working pulse are obtained by the load terminal sampling branch. Based on the load terminal voltage waveform and load terminal current waveform, a steep-edge pulse energy shaping result is generated. The steep-edge pulse energy shaping result includes pulse rising edge index, square top flatness index, effective pulse width index, and pulse energy index.

[0079] It should be noted that the reflection determination threshold in this embodiment is determined by combining the allowable waveform overshoot at the load end and the withstand voltage margin of the matching network. When the reflection characteristic is too large, the superposition of the reflected wave and the incident wave can easily form a local overvoltage at the forming network node, and the top ripple and ringing at the load end will increase. Setting the threshold to 0.10 can usually limit the peak value of the reflection component to within 10% of the incident peak value, so that the overshoot risk in the working pulse stage is within a controllable range.

[0080] In a preferred embodiment, the load-side sampling branch includes a voltage sampling channel and a current sampling channel; wherein the voltage sampling channel may be a combination of a high-frequency high-voltage divider and an isolation sampling module; the current sampling channel may be a combination of a Rogowski coil or a current transformer and an integration / conditioning module; both channels are connected to the same high-speed sampling module and share a trigger reference, the trigger reference being the synchronous output of the forming switch trigger signal.

[0081] As an example, the pulse rise time indicator is the time taken for the load-side voltage waveform to rise from 10% of its peak value to 90% of its peak value; its mathematical formula is as follows: ; in, As the rising edge indicator, This refers to the moment when the load-side voltage waveform first reaches 10% of its peak value. This is the moment when the load-side voltage waveform first reaches 90% of its peak value.

[0082] As an example, the flatness index for the top of the square is: within the time window of the square top, the flatness is measured by the ratio of the difference between the maximum and minimum values ​​of the load-side voltage to the average value; its mathematical formula is as follows: ; in, This is an index for the flatness of the square top. This represents the maximum value of the load terminal voltage within the square-top time window. This represents the minimum load-side voltage within the square-top time window. This is the average value of the load terminal voltage within the square-top time window, which is from 20 ns after the rising edge ends to 20 ns before the falling edge begins.

[0083] As an example, the effective pulse width specification is defined as the duration during which the load-side voltage waveform is higher than 50% of its peak value; its mathematical formula is as follows: ; in, For effective pulse width index, This refers to the moment when the load-side voltage waveform first reaches 50% of its peak value during the rise process. This refers to the moment when the load-side voltage waveform last reaches 50% of its peak value during the decline process.

[0084] As an example, pulse energy index: (Refer to...) Figure 4 The instantaneous power at the load end is obtained by integrating the power over the time window corresponding to the effective pulse width; the mathematical formula is as follows: ; in, For pulse energy indicators, This is the voltage waveform at the load end. This is the current waveform at the load end. Let the time infinitesimal be the integral element, and take the upper and lower limits of integration. and .

[0085] As an example, if the peak voltage at the load terminal of the working pulse is 10 kV, the peak current at the load terminal is 200 A, the rise time is 18 ns, the effective pulse width is 210 ns, the square top flatness is 0.035, and the energy is 42 J.

[0086] In a preferred example, the pulse shaping circuit serves as the pulse power stage of the high-voltage pulse generation circuit, with a nominal 50 Ω equivalent load at the load end, a target charging voltage of 20 kV, a voltage tolerance threshold of 200 V, and a reflection determination threshold of 0.10.

[0087] In this application scenario, at the start of stage S1, the charging switch is closed, and the voltage at the end of the energy storage capacitor bank rises to 19.92 kV within 4.8 ms and enters the final convergence stage. After the control unit reads that the nominal impedance level of the load is 50 Ω, it obtains the initial segment identifier PFN-5 / BL-2 / MN-3 by querying the shaping segment selection table, and sequentially closes the PFN selection switch and the Blumlein selection switch, connecting to the third segment of the matching network. Then, in stage S2, after determining that the charging voltage has reached the target value, a test trigger signal with a calibrated pulse width of 60 ns is output, and the shaping switch closes and releases a test pulse. The output sampling branch separates the incident component peak value of 9.6 kV and the reflection component peak value of 1.2 kV, with a reflection characteristic of 0.125, which is greater than the reflection judgment threshold. In stage S3, the first candidate groups MN-2 and MN-4 are constructed and tested one by one. When switching to PFN-5 / BL-2 / MN-4, the incident component peak value is 9.5 kV and the reflection component peak value is 0.7 kV. kV, reflection characteristic 0.074; this candidate is ranked smallest in the candidate result table, written as the current initial segment identifier and triggers the retest test pulse, the retest reflection characteristic is stable within 0.08; entering the S4 stage, the control unit triggers the shaping switch to output working pulse, the load end sampling branch records the load end voltage peak 10.0 kV, the load end current peak 198 A, the rise edge index 18 ns, the square top flatness 0.035, the effective pulse width 210 ns, and the energy index 42 J; the above indicators are consistent with the target under the same range, forming a traceable steep edge pulse energy shaping result record.

[0088] Preferably, during the test pulse stage, the segment combination and segment matching have been adjusted to a low reflection state, and the energy release during the working pulse stage is closer to the load absorption condition, reducing the risk of waveform distortion and overshoot at the load end. At the same time, the synchronous sampling of the load end voltage waveform and the load end current waveform solidifies the forming effect in an indexed manner, which facilitates the comparison of the forming quality of different segment combinations.

[0089] Other aspects disclosed in the embodiments of the present invention also provide a computer device including one or more processors and a memory.

[0090] The memory is used to store operable instructions that, when executed by the one or more processors, cause the one or more processors to perform operations, including the flow of the steep-edge pulse energy shaping method based on the pulse shaping circuit of the foregoing embodiments, especially... Figure 1 The flowchart of the method is shown.

[0091] Other aspects disclosed in the embodiments of the present invention also propose a computer-readable medium for storing software including instructions executable by one or more computers, which, upon execution, cause the one or more computers to perform operations including the flow of the steep-edge pulse energy shaping method based on pulse shaping circuits of the foregoing embodiments, particularly... Figure 1 The flowchart of the method is shown.

[0092] It should be recognized that embodiments of the present invention may be implemented or carried out by computer hardware, a combination of hardware and software, or by computer instructions stored in a non-transitory computer-readable storage medium.

[0093] The method can be implemented using standard programming techniques, including a non-transitory computer-readable storage medium configured with a computer program in the computer program, wherein the storage medium is configured such that the computer operates in a specific and predefined manner.

[0094] Each program can be implemented in a high-level procedural or object-oriented programming language to communicate with the computer system; however, if required, the program can be implemented in assembly or machine language.

[0095] In any case, the language can be either compiled or interpreted.

[0096] Furthermore, for this purpose, the program can run on programmed application-specific integrated circuits.

[0097] The processes described herein (or variations and / or combinations thereof) can be executed under the control of one or more computer systems configured with executable instructions, and can be implemented by hardware or a combination thereof as code (e.g., executable instructions, one or more computer programs, or one or more applications) that commonly executes on one or more processors. The computer program includes a plurality of instructions executable by one or more processors.

[0098] Furthermore, the method can be implemented in any suitable computing platform, including but not limited to personal computers, minicomputers, mainframes, workstations, networked or distributed computing environments, standalone or integrated computer platforms, or in communication with charged particle tools or other imaging devices.

[0099] Various aspects of the present invention can be implemented in machine-readable code stored on a non-transitory storage medium or device, whether portable or integrated into a computing platform, such as a hard disk, optical read and / or write storage medium, RAM, ROM, etc., such that it can be read by a programmable computer, and when the storage medium or device is read by the computer, it can be used to configure and operate the computer to perform the processes described herein.

[0100] Furthermore, machine-readable code, or parts thereof, can be transmitted via wired or wireless networks.

[0101] When such media includes instructions or programs that combine with a microprocessor or other data processor to implement the steps described above, the invention described herein includes these and other different types of non-transitory computer-readable storage media.

[0102] 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 it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method of forming the energy of a steep-fronted pulse based on a pulse-shaping circuit, characterized by, The method comprises the following steps: charging the energy storage capacitor group in the pulse forming circuit within a preset charging period, and initially gating the forming network composed of PFN segments and Blumlein transmission line segments and the impedance gradient matching network; after the charging voltage of the energy storage capacitor group reaches a target value, triggering the forming switch to output a test pulse, and obtaining the reflection characteristic quantity of the test pulse at the output sampling branch; according to the reflection characteristic quantity, using the minimum reflection criterion to update the segment impedance configuration of the impedance gradient matching network and the segment combination of the forming network, and after completion, triggering the forming switch to output a retest test pulse, and obtaining a retest reflection characteristic quantity of the retest test pulse; when the retest reflection characteristic quantity is less than or equal to a reflection judgment threshold, triggering the forming switch to output a working pulse, and obtaining an energy forming result of the steep pulse at the load end connected to the output end of the pulse forming circuit.

2. The pulse shaping circuit based steep front pulse energy shaping method of claim 1, wherein, The initial gating of the forming network composed of PFN segments and Blumlein transmission line segments and the impedance gradient matching network comprises the following steps: at the beginning of the preset charging period, connecting the energy storage capacitor group in the pulse forming circuit and the charging power source through a charging switch to form a charging loop; during the conduction of the charging loop, collecting the terminal voltage of the energy storage capacitor group as the charging voltage, and reading the nominal impedance level of the load connected to the output end of the pulse forming circuit; according to the charging voltage and the nominal impedance level of the load, determining an initial segment identifier in the forming segment gating table, and sequentially closing the PFN gating switch and the Blumlein gating switch according to the initial segment identifier, so as to complete the initial gating of the forming network composed of PFN segments and Blumlein transmission line segments; after the initial gating of the forming network is completed, closing the matching network gating switch according to the initial segment identifier to connect the impedance gradient matching network, and completing the initial gating of the impedance gradient matching network.

3. The pulse shaping circuit based steep front pulse energy shaping method of claim 2, wherein, The forming segment gating table is a segment corresponding relationship table obtained offline for different charging voltage levels and nominal impedance levels of the load. The table entries of the forming segment gating table are stored in the form of the initial segment identifier, wherein the initial segment identifier includes the PFN segment gating identifier, the Blumlein transmission line segment gating identifier, and the segment gating identifier of the impedance gradient matching network.

4. The pulse shaping circuit based steep front pulse energy shaping method of claim 1, wherein, The reflection characteristic quantity of the test pulse is obtained by the following steps: within the preset charging period, sampling the terminal voltage of the energy storage capacitor group through a voltage sampling branch to obtain a charging voltage, and comparing the charging voltage with a target charging voltage; after the charging voltage of the energy storage capacitor group reaches the target value, outputting a test trigger signal to the test trigger control end, and closing the forming switch within the calibration pulse width of the test trigger signal, so that the forming network and the impedance gradient matching network release a test pulse to the load end; during the test pulse output, obtaining the incident amplitude and the reflection amplitude by the output sampling branch respectively, and generating the reflection characteristic quantity based on the amplitude ratio of the incident amplitude and the reflection amplitude.

5. The pulse shaping circuit based steep front pulse energy shaping method of claim 4, wherein, The method of difference comparison between the charging voltage and the target charging voltage comprises: When the absolute value of the difference is less than or equal to a voltage tolerance threshold, the charging voltage of the energy storage capacitor bank reaches a target value; When the absolute value of the difference is greater than the voltage tolerance threshold, the charging loop is maintained to be turned on and the energy storage capacitor bank is continuously charged until the absolute value of the difference is less than or equal to the voltage tolerance threshold.

6. The pulse shaping circuit based steeped pulse energy shaping method of claim 1, wherein, The method of gating update according to the reflection characteristic quantity comprises: Based on the reflection characteristic quantity, a gating control unit is triggered to enter a gating update process, and a matching segment identifier and a shaping segment identifier are obtained, wherein the matching segment identifier is a segmented impedance configuration of the impedance gradual matching network, and the shaping segment identifier is a segment combination of the shaping network; A candidate gating instruction is output according to a single-variable switching rule, wherein the single-variable switching rule comprises: when the shaping segment identifier is kept unchanged, only the matching segment identifier is switched between adjacent segments to obtain a first candidate group; and when the matching segment identifier is kept unchanged, only the shaping segment identifier is switched between adjacent segment combinations to obtain a second candidate group; A test pulse is triggered for each of the first candidate group and the second candidate group respectively, and corresponding candidate reflection characteristic quantities are generated, and a target candidate gating instruction is determined according to a minimum reflection criterion that the candidate reflection characteristic quantity amplitude is minimum; The matching segment identifier and the shaping segment identifier are updated according to the target candidate gating instruction, so as to complete the gating update of the segmented impedance configuration of the impedance gradual matching network and the segment combination of the shaping network.

7. The pulse shaping circuit based sharp-edged pulse energy shaping method according to claim 1, characterized in that, The method of comparison between the retest reflection characteristic quantity and the reflection determination threshold comprises: When the retest reflection characteristic quantity is greater than the reflection determination threshold, a gating update instruction is output and the next round of gating update is returned to the previous step; When the retest reflection characteristic quantity is less than or equal to the reflection determination threshold, a shaping switch is triggered to output a working pulse, and an edge pulse energy shaping result is obtained at a load end connected to an output end of the pulse shaping circuit.

8. The pulse shaping circuit based steep front pulse energy shaping method of claim 7, wherein, The working pulse output at the load end connected to the output end of the pulse shaping circuit, and during the working pulse output, a load end voltage waveform and a load end current waveform of the working pulse are obtained by a load end sampling branch, and the edge pulse energy shaping result is generated based on the load end voltage waveform and the load end current waveform, wherein the edge pulse energy shaping result comprises a pulse rising edge indicator, a square top flatness indicator, an effective pulse width indicator and a pulse energy indicator.

9. A computer device, comprising: Comprise: One or more processors; A memory storing instructions operable to cause the one or more processors to perform operations when executed by the one or more processors, the operations comprising the flow of the edge pulse energy shaping method based on the pulse shaping circuit according to any one of claims 1-8.

10. A computer readable medium storing software, characterized in that: The software includes instructions executable by one or more computers, the instructions, through such execution, causing the one or more computers to perform operations comprising a flow of the method of shaping the energy of a steeped pulse based on a pulse-shaping circuit as claimed in any one of claims 1-8.

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