A single-capacitor parallel resonant modulation type quasi-square wave pulse generator

Abstract

The application belongs to the technical field of high-voltage pulse and specifically discloses a single-capacitor parallel resonant modulation type quasi-square wave pulse generator and a control method. The quasi-square wave pulse generator comprises a primary charging unit for providing positive and negative charging voltages, a Marx voltage boosting unit comprising multiple-stage parallel capacitor groups, a synchronous switch and a trigger unit for controlling the synchronous series conduction of the capacitor groups, and a single-capacitor modulation unit in parallel with the previous-stage capacitor group. The single-capacitor modulation unit is an LC series circuit. During charging, the voltage across the single-capacitor modulation unit is the same, and the single-capacitor modulation unit does not participate in the charging and energy storage process. During discharging, the previous-stage capacitor group discharges the single-capacitor modulation unit, so that the single-capacitor modulation unit participates in the modulation of the output pulse wave, and a quasi-square wave pulse signal with a fixed pulse width is formed on the matched load. The application realizes quasi-square wave pulse modulation based on the principle of single-capacitor resonance, and has a simple structure, which is conducive to improving the energy density of the pulse generator.

Description

Technical Field

[0001] This application belongs to the field of high voltage pulse technology, and more specifically, relates to a single-capacitor parallel resonant modulation quasi-square wave pulse generator. Background Technology

[0002] With the development of pulse generators, higher demands are placed on miniaturization and compactness, as well as higher quality quasi-square waves. This requires pulse generators to have waveform modulation capabilities and synchronous triggering capabilities for cascaded switches. The Marx generator, with its simple structure and modular stacking for multi-stage voltage boosting, allows for the design of integrated high-voltage switches, facilitating nanosecond-level synchronization of multiple switches and making it the preferred technology for miniaturized and compact pulse generator devices. A traditional Marx generator can be equivalent to an LC series discharge, producing a double exponential wave output waveform, requiring modulation of the output waveform using a pulse forming network (PFN). A typical pulse forming network is shown below. Figure 1 As shown. Based on the parameter settings of capacitance and inductance, pulse forming networks can be divided into Rayleigh networks with equal capacitance and inductance, and Guillemin networks with unequal capacitance and inductance.

[0003] Rayleigh networks are easier to implement in engineering, but their modulation networks are generally more complex, requiring high switching synchronization. In the process of constructing a multi-stage PFN-Marx network, strong electromagnetic coupling occurs between different PFN stages, affecting waveform modulation quality. Furthermore, parasitic parameters after multi-stage stacking are difficult to control, resulting in poor output waveform quality. In addition, the volume of pulse-generating networks composed of capacitors and inductors increases significantly. Although each capacitor acts as an energy storage capacitor, the discrete energy storage of the capacitors results in a lower overall energy density for the pulse generator compared to a Marx generator. Guillemin networks include series resonant networks, parallel resonant networks, anti-resonant networks, and ladder networks. While Guillemin networks are structurally simple, their capacitors and inductors are theoretically calculated, resulting in low adjustment flexibility. Additionally, some capacitors are not used as energy storage capacitors in the circuit, significantly reducing the overall energy density of the pulse generator. For example... Figure 2 Taking the anti-resonant network shown as an example, besides capacitor C0 acting as an energy storage capacitor, C6, C7, and C8 exist as modulation capacitors and do not have an energy storage function. Furthermore, the waveform modulation quality is closely related to the number of sections in the anti-resonant network; a better modulation effect can only be obtained when the number of sections is ≥3. In addition, this network is limited by the voltage rating of the modulation capacitors, making it difficult to achieve higher power pulse output. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the prior art, this application provides a single-capacitor parallel resonant modulation quasi-square wave pulse generator, which aims to solve the technical problem that the low energy storage density of the existing pulse transmitter is not conducive to miniaturization.

[0005] To achieve the above objectives, in a first aspect, this application provides a single-capacitor parallel resonant modulation quasi-square wave pulse generator, comprising:

[0006] The primary charging unit is used to provide both positive and negative charging voltages;

[0007] The Max boost unit includes a multi-stage parallel capacitor bank, which includes a first capacitor, a second capacitor, a first charging inductor, a second charging inductor, and a ground isolation inductor. The first charging inductor is connected in series between the first capacitor and the positive charging voltage, the second charging inductor is connected in series between the second capacitor and the negative charging voltage, and the two ends of the ground isolation inductor are respectively connected to the ground terminals of the first capacitor and the second capacitor.

[0008] Synchronous switches and triggering units are located in each stage of the capacitor bank and are used to control the synchronous series conduction of each stage of the capacitor bank.

[0009] The single-capacitor modulation unit is an LC series circuit, and the first terminal of the LC series circuit is connected to a preset... Level and Between the grounding terminals of the first capacitor bank, the second terminal is grounded.

[0010] Preferably, the preset Level and A tuning inductor is connected in series between the ground terminals of the capacitor bank. The first terminal of the LC series circuit is connected to the tuning inductor and... Between capacitor banks.

[0011] Preferably, the inductance value of the tuning inductor is in the range of 100nH to 1μH.

[0012] Preferred, .

[0013] Preferably, the single-capacitor modulation unit includes a modulation capacitor, the high-voltage terminal connecting wire of the modulation capacitor is regarded as an inductor in an LC series circuit, and the outer shell of the modulation capacitor serves as a ground terminal.

[0014] Preferably, the capacitance value of the modulation capacitor is adjustable in the range of 100pF-1000pF.

[0015] Preferably, the synchronous switch and triggering unit includes multiple synchronous switches, with a unique synchronous switch connected to each capacitor bank. The first end of the synchronous switch is connected between the first capacitor and the first charging inductor, and the second end of the synchronous switch is connected between the second capacitor and the second charging inductor.

[0016] Preferably, the synchronization switch is a gas synchronization switch or a solid synchronization switch.

[0017] Preferably, the connection is made in the front. The synchronous switch in the capacitor bank includes a switch trigger electrode. ,in This represents the total number of synchronous switches in the synchronous switch and triggering unit.

[0018] Secondly, this application implements a control method for a single-capacitor parallel resonant modulation quasi-square wave pulse generator. The control method is based on any of the single-capacitor parallel resonant modulation quasi-square wave pulse generators described in the first aspect, and specifically includes the following steps:

[0019] The primary charging unit charges the Max boost unit;

[0020] Charging stops when the voltage in each capacitor bank reaches a preset value.

[0021] Synchronous switches and triggering units control the synchronous series conduction of each stage of capacitor banks, and the series discharge of each stage of capacitor banks.

[0022] forward The capacitor bank discharges to the single capacitor modulation unit, generating a reverse resonant pulse, which participates in the modulation of the output pulse wave, forming a quasi-square wave pulse signal with a fixed pulse width on the matched load.

[0023] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art:

[0024] (1) The quasi-square wave pulse transmitter of this application can obtain a high-quality quasi-square wave pulse signal by modulating the hyperbolic pulse signal output by the Max generator with a single capacitor. Compared with the existing pulse forming network for modulation, the waveform modulation quality of this application is not limited by the number of modulation network levels. Only a single-level modulation is needed to obtain a high-quality quasi-square wave pulse signal, thereby reducing the complexity of the system and facilitating system miniaturization.

[0025] (2) The quasi-square wave pulse transmitter of this application uses a single capacitor to modulate the quasi-square wave pulse signal. Compared with the existing pulse forming network for modulation, it has a simple structure, can reduce interstage electromagnetic coupling and parasitic parameters, thereby reducing the synchronization requirements of the overall circuit for switching devices and improving the output waveform quality.

[0026] (3) The quasi-square wave pulse transmitter of this application uses a single capacitor to modulate the quasi-square wave pulse signal. Except for the single capacitor used to modulate the waveform, the other capacitors are energy storage capacitors, so the energy storage density is greater than that of the existing square wave pulse transmitter.

[0027] (4) The capacitor in the Max boost unit of this application adopts positive and negative bipolar charging. Compared with unipolar charging, the voltage multiplication benefit of this application is greater.

[0028] (5) The capacitance value of the modulation capacitor in the single capacitor modulation unit of this application is adjustable in the range of hundreds of picofarads. The output pulse width can be adjusted by adjusting its parameters, which is beneficial to the practical application of this type of pulse generator. Attached Figure Description

[0029] Figure 1 This is a circuit diagram of a typical pulse forming network in the background technology of this application.

[0030] Figure 2 This is a circuit diagram of the anti-resonant network in the background technology of this application.

[0031] Figure 3 This is a schematic diagram of the single-capacitor parallel resonant modulation quasi-square wave pulse generator provided in the embodiments of this application.

[0032] Figure 4 This is a circuit diagram of a single-capacitor parallel resonant modulation quasi-square wave pulse generator provided in an embodiment of this application.

[0033] Figure 5 This is a high-voltage quasi-square wave pulse waveform diagram provided in the embodiments of this application.

[0034] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0035] 1 is the Max boost unit; 2 is the primary charging unit; 3 is the synchronous switch and trigger unit; 4 is the single capacitor modulation unit. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0037] The terms "first" and "second," etc., used in the specification and claims herein are used to distinguish different objects, not to describe a specific order of the objects. For example, "first capacitor" and "second capacitor," etc., are used to distinguish different capacitors, not to describe a specific order of the capacitors.

[0038] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0039] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple capacitor banks means two or more capacitor banks, multiple synchronous switches means two or more synchronous switches, etc.

[0040] like Figure 3 The diagram shown is a schematic representation of a single-capacitor parallel resonant modulation quasi-square wave pulse transmitter according to an embodiment of this application. It includes a Max boost unit 1, a primary charging unit 2, a synchronous switch and triggering unit 3, and a single-capacitor modulation unit 4. The primary charging unit 2 provides positive and negative charging voltages to the Max boost unit 1. The capacitors in the Max boost unit 1 use bipolar charging to store electrical energy. After charging is complete, the synchronous switch and triggering unit 3 controls the synchronous series conduction of each capacitor bank in the Max boost unit 1. The single-capacitor modulation unit 4 participates in the quasi-square wave modulation process during charging, ultimately forming a fixed-width quasi-square wave pulse signal on the matched load.

[0041] This application proposes an embodiment 1 of a single-capacitor parallel resonant modulation quasi-square wave pulse transmitter. The circuit diagram of embodiment 1 is shown below. Figure 4 As shown:

[0042] In the diagram, the primary charging unit generates microsecond-level high-voltage pulse signals through a pulse transformer, which are divided into positive voltage output +HV and negative voltage output -HV, respectively charging the two capacitors in each capacitor bank of the Max boost unit.

[0043] In the diagram, the Marx boost unit specifically comprises n parallel capacitor banks, each containing two capacitors, two charging inductors, and one isolation inductor. The first charging inductor is connected in series between the first capacitor and the positive charging voltage, and the second charging inductor is connected in series between the second capacitor and the negative charging voltage. The two ends of the ground isolation inductor are respectively connected to the ground terminals of the first and second capacitors.

[0044] In the Marx boost unit, the capacitor bank connected in parallel in the first a stages constitutes the Marx boost unit A, and the capacitor bank connected in parallel in the last b stages constitutes the Marx boost unit B, where a + b = n.

[0045] Inside Marx boost unit A and Marx boost unit B, the ground terminals of adjacent capacitor banks are connected by the shortest possible wire, and the ground terminals of Marx boost unit A and Marx boost unit B are connected by a tuning inductor L10.

[0046] In each capacitor bank, the high-voltage terminal of the first capacitor is connected to the negative charging voltage through the first charging inductor, thus charging with a negative charge. (See [reference]). Figure 4 C9, C11, C13, C15, and C17.

[0047] In each capacitor bank, the high-voltage terminal of the second capacitor is connected to the positive charging voltage through the second charging inductor, and is positively charged. See [link / reference]. Figure 4 C10, C12, C14, C16, and C18.

[0048] Therefore, a negative high-voltage pulse can be obtained on the matching load resistor R2, and vice versa, a positive high-voltage pulse can be obtained.

[0049] Figure 4 In this circuit, the synchronous switch and triggering unit includes multiple synchronous switches. Each capacitor bank has a unique synchronous switch connected to it. The first terminal of the synchronous switch is connected between the first capacitor and the first charging inductor, and the second terminal is connected between the second capacitor and the second charging inductor. The synchronous switch St includes a trigger electrode and is a trigger-type gas synchronous switch. Synchronous switches Si (i=1, 2, 3, ...) are self-breakdown type gas synchronous switches. Compared to the self-breakdown type gas synchronous switch Si, the trigger-type gas synchronous switch St adds a trigger electrode, allowing for stable breakdown under an applied trigger pulse. The synchronous switches in the first m capacitor banks are trigger-type gas synchronous switches, while the rest are self-breakdown type gas synchronous switches.

[0050] Figure 4 In the circuit, the single-capacitor modulation unit is an LC series circuit, which includes a modulation capacitor Cm and a modulation inductor Lm. The first end of the LC series circuit is connected between the tuning inductor L10 and the ground terminal of the Marx boost unit B, and the second end is grounded.

[0051] Based on this, as application requirements continue to deepen, this application can adjust the output pulse width of tens of nanoseconds by adjusting the capacitance value of the modulation capacitor Cm and the inductance values ​​of the modulation inductor Lm and the tuning inductor L10.

[0052] Initially, the primary charging unit boosts the low-voltage DC signal (less than 800V) from the mains, battery, or supercapacitor to a microsecond pulse signal of tens of kilovolts. The pulse signal from the primary charging unit is output in both positive and negative paths, charging the capacitors in the Max boost unit in parallel. When the voltage across the capacitors in the Max boost unit reaches a preset value, the first m-stage synchronous switches are triggered and turned on under the influence of a high-voltage trigger signal, and the subsequent nm-stage switches are rapidly and synchronously turned on after self-breakdown. The synchronous switches cause the voltage of each stage to rise, while the Marx boost unit A discharges the modulation capacitor Cm in the single-capacitor modulation unit. The single-capacitor modulation unit participates in the quasi-square wave modulation process, ultimately forming a fixed-width quasi-square wave pulse signal on the matched load R2. Here, the fixed pulse width is determined by the circuit parameters of both the Max boost unit and the single-capacitor modulation unit.

[0053] This application also proposes a second embodiment of a single-capacitor parallel resonant modulation quasi-square wave pulse transmitter, in which:

[0054] The Max boost unit includes an n-stage capacitor bank, each containing two pulse capacitors, which can be ceramic or metal film capacitors, etc. Their withstand voltage level Ub is determined based on the peak output pulse voltage Up: Ub > Up / n. The capacitor bank also includes two charging inductors and one isolation inductor, with inductance values ​​ranging from approximately 10μH to 100μH depending on output specifications.

[0055] The primary charging unit is a high-voltage constant current power supply. Its main function is to charge the capacitor bank of the Max boost unit. The charging voltage is ±Uc, which is determined by the peak value of the output pulse voltage: Uc=Up / n.

[0056] The synchronous switch and its triggering unit include n synchronous switches, one synchronous switch is located in a capacitor bank, and the two ends of the synchronous switch are connected between the high voltage ends of two charging inductors.

[0057] The synchronous switch mainly consists of a synchronous switch group and a matching trigger unit. The trigger unit converts the external optical signal into a synchronous trigger signal for the synchronous switch, so that n synchronous switches are turned on synchronously, and the capacitor group in the Max boost unit completes series discharge, pumping the voltage to n times the charging voltage.

[0058] The single-capacitor modulation unit is connected in parallel with the first a-stage capacitor bank of the Max boost unit. The first terminal of the single-capacitor modulation unit is grounded, and the second terminal is connected to the high-voltage terminal of the tuning inductor L10. The value of the tuning inductor L10 ranges from 100nH to 1μH.

[0059] The single-capacitor modulation unit includes a modulation capacitor Cm and a modulation inductor Lm. The modulation capacitor Cm has an adjustment range of 100pF-1000pF, and the modulation inductor Lm has a value range of less than 1μH. When the capacitor bank in the Max boost unit discharges in series, the first a-stage capacitor bank discharges onto the modulation capacitor Cm, generating a reverse resonant pulse that participates in the modulation of the quasi-square wave output pulse, ultimately modulating the hyperbolic pulse signal output by the Max boost unit into a quasi-square wave pulse signal.

[0060] This application also proposes Embodiment 3, which introduces a technical solution for outputting a quasi-square wave pulse signal with a pulse half-width greater than 100ns:

[0061] In Example 3, a 10-stage capacitor bank is used to form a Max boost unit. Each stage of the Max boost unit consists of two 20nF pulse capacitors connected in parallel, with an isolation inductance of 30μH and a charging inductance of 20μH.

[0062] The single-capacitor modulation unit is connected in parallel with the first-stage capacitor bank (a=1), meaning the single-capacitor modulation unit is connected in parallel with the first-stage capacitor bank. The modulation capacitor Cm is 450pF, and the modulation inductor Lm is 20nH.

[0063] The grounding terminals of the last 9 capacitor banks and the first capacitor bank are connected by a tuning inductor L10, which is 500nH, and the load impedance R2 is 50 ohms.

[0064] A quasi-square wave pulse generator constructed using a 10-stage capacitor bank outputs a voltage of ±520kV, and its output pulse waveform is as follows: Figure 5 As shown, the output pulse width at the flat top (90%-90% peak voltage) is 60ns, the output pulse half-width (50%-50% peak voltage) is 103ns, and the peak voltage is 518kV. It can be seen that, after modulation by the single-capacitor modulation unit, the quasi-square wave pulse generator of this application can output high-quality quasi-square wave pulses.

[0065] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0066] Furthermore, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0067] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after connection. "Rotary connection" refers to a connection where the components can rotate relative to each other after connection. "Sliding connection" refers to a connection where the components can slide relative to each other after connection. The directional terms mentioned in the embodiments of this application, such as "top," "bottom," "inner," "outer," "left," and "right," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0068] Furthermore, the mathematical concepts mentioned in the embodiments of this application, such as symmetry, equality, parallelism, and perpendicularity, are limitations specific to the current technological level, rather than absolute and strict mathematical definitions. Slight deviations are permissible; approximations of symmetry, equality, parallelism, and perpendicularity are all acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. "A and B are perpendicular" means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0069] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A single-capacitor parallel resonant modulation quasi-square wave pulse generator, characterized in that, include: The primary charging unit is used to provide both positive and negative charging voltages; The Max boost unit includes a multi-stage parallel capacitor bank, which includes a first capacitor, a second capacitor, a first charging inductor, a second charging inductor, and a ground isolation inductor. The first charging inductor is connected in series between the first capacitor and the positive charging voltage, the second charging inductor is connected in series between the second capacitor and the negative charging voltage, and the two ends of the ground isolation inductor are respectively connected to the ground terminals of the first capacitor and the second capacitor. Synchronous switches and triggering units are located in each stage of the capacitor bank and are used to control the synchronous series conduction of each stage of the capacitor bank. The single-capacitor modulation unit is an LC series circuit, and the first terminal of the LC series circuit is connected to a unique pair of preset... Level and Between the grounding terminals of the first capacitor bank, the second terminal is grounded.

2. The single-capacitor parallel resonant modulation quasi-square wave pulse generator according to claim 1, characterized in that, The preset Level and A tuning inductor is connected in series between the ground terminals of the capacitor bank. The first terminal of the LC series circuit is connected to the tuning inductor and... Between capacitor banks.

3. The single-capacitor parallel resonant modulation quasi-square wave pulse generator according to claim 2, characterized in that, The inductance value of the tuned inductor is in the range of 100nH to 1μH.

4. The single-capacitor parallel resonant modulation quasi-square wave pulse generator according to claim 1 or 2, characterized in that, 。 5. The single-capacitor parallel resonant modulation quasi-square wave pulse generator according to claim 1, characterized in that, The single-capacitor modulation unit includes a modulation capacitor. The high-voltage terminal connecting wire of the modulation capacitor is regarded as an inductor in an LC series circuit, and the outer shell of the modulation capacitor serves as a ground terminal.

6. The single-capacitor parallel resonant modulation quasi-square wave pulse generator according to claim 5, characterized in that, The capacitance value of the modulation capacitor can be adjusted within the range of 100pF-1000pF.

7. The single-capacitor parallel resonant modulation quasi-square wave pulse generator according to claim 1, characterized in that, The synchronous switch and triggering unit includes multiple synchronous switches, with a unique synchronous switch connected to each capacitor bank. The first end of the synchronous switch is connected between the first capacitor and the first charging inductor, and the second end of the synchronous switch is connected between the second capacitor and the second charging inductor.

8. The single-capacitor parallel resonant modulation quasi-square wave pulse generator according to claim 7, characterized in that, The synchronization switch is specifically a gas synchronization switch or a solid synchronization switch.

9. The single-capacitor parallel resonant modulation quasi-square wave pulse generator according to claim 7, characterized in that, Connection first The synchronous switch in the capacitor bank includes a switch trigger electrode. ,in This represents the total number of synchronous switches in the synchronous switch and triggering unit.

10. A control method for a single-capacitor parallel resonant modulation quasi-square wave pulse generator, characterized in that, The control method, based on the single-capacitor parallel resonant modulation quasi-square wave pulse generator according to any one of claims 1-9, specifically includes the following steps: The primary charging unit charges the Max boost unit; Charging stops when the voltage in each capacitor bank reaches a preset value. Synchronous switches and triggering units control the synchronous series conduction of each stage of capacitor banks, and the series discharge of each stage of capacitor banks. forward The capacitor bank discharges to the single capacitor modulation unit, generating a reverse resonant pulse, which participates in the modulation of the output pulse wave, forming a quasi-square wave pulse signal with a fixed pulse width on the matched load.

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