A pulse top droop compensation circuit for a resonant circuit based Marx generator

Abstract

The application discloses a pulse top drop compensation circuit of a Marx generator based on a resonance circuit, and comprises: compensation of pulse top drop under different loads and different pulse widths. In applications such as particle accelerators, the voltage and current top drop of a high-voltage pulse should be as low as possible; in the Marx generator, when the resonance inductance and the compensation switch are connected in series and are connected in parallel with the main capacitor in the common unit, the compensation unit is obtained. In the discharge process, the nearly linear part of the sine voltage is added to the load as pulse compensation, and a nearly top-drop-free rectangular pulse is realized. Different compensation unit numbers can compensate the voltage top drop to different degrees, and the compensation effect is adjustable. In addition, as long as the resonance control switch is turned off, the compensation units can also work as common units in the Marx generator, so as to be utilized. According to the application, the compensation degree can be adjusted, the capacitance and the system cost can be greatly reduced, and good feasibility and application prospect are possessed.

Description

Technical Field

[0001] The present invention relates to the technical field of pulse power, and in particular to a pulse droop compensation circuit of a Marx generator based on a resonance circuit. Background Art

[0002] The widespread use of semiconductor switches in Marx generators has enabled them to generate square wave pulses, control the number, width, amplitude, and frequency of pulses, and handle different loads. This has enabled Marx generators to be applied in various fields, including biomedicine, environmental protection, low-temperature plasma generation, and the military. Many industrial applications often place high demands on output voltage flatness. However, when the energy storage capacitors of a Marx generator are discharged in series, the voltage on the capacitors gradually decreases as the load is discharged. This requires the capacitor capacity to be increased exponentially, significantly increasing the system's cost, size, and weight, and reducing efficiency.

[0003] T. Tang of the National Accelerator Laboratory in the United States added an additional stage of mini-Marx circuit named "Vernier" to the unipolar Marx generator. The circuit contains multiple "Vernier" units, which are turned on in sequence for time-sharing compensation. However, this solution requires a very complex control system and multiple auxiliary power supplies. In addition, the compensated waveform is discontinuous in the flat-top stage and presents a sawtooth wave. See "Tang T, Burkhart C, Nguyen MA vernier regulator for ILC Marx droop compensation [C]. 2009 IEEE Pulsed Power Conference, 2009: 1402-1405". Fermi National Laboratory in the United States added a "bouncer" circuit to their Marx modulator, containing a capacitor and inductor to generate a resonant voltage applied to the discharge pulse to compensate for voltage droop. However, this solution also requires an auxiliary power supply to charge the capacitor in the "bouncer" circuit, which is bulky and expensive. See "Pfeffer H, et al. A long pulse modulator for reduced size and cost [C]. Twenty-First International Power Modulator Symposium Conference, 1994: 48-51". R.L. Cassel of Stangenes Industries in the United States built on this, using a capacitor-inductor filter and a step-up transformer to eliminate the need for an auxiliary charging source, while also reducing size and cost. See "Cassel R.L. Pulsed voltage droop compensation for solid-state Marx modulator [C]. 2008 IEEE International Power Modulators and High-Voltage Conference, 2008: 117-119". Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a pulse droop compensation circuit for a Marx generator based on a resonant circuit, which can adjust the degree of compensation and significantly reduce the capacitance and system cost, and has good feasibility and application prospects. In order to achieve the above-mentioned purpose and other advantages of the present invention, a pulse droop compensation circuit for a Marx generator based on a resonant circuit is provided, comprising:

[0005] at least one resonance compensation unit;

[0006] at least one common unit, the common unit being connected in series with the resonance compensation unit, the common unit comprising at least one diode, a capacitor connected in parallel with the diode, a charge control switch connected in series with the diode, and a discharge control switch connected in series with the charge control switch;

[0007] a DC power supply, the DC power supply being connected in series with the resonant compensation unit and the common unit, and the DC power supply being used to charge the capacitors in the common unit and the compensation unit;

[0008] A load is connected in parallel with the resonant compensation unit and the common unit, wherein the resonant compensation unit is used to discharge the load, and the pulse droop occurring in the discharge pulse is compensated to varying degrees by controlling the number of compensation units.

[0009] Preferably, the resonance compensation unit includes all components of the common unit, at least one resonant inductor connected in parallel with the capacitor, and a resonant control switch connected in series with the resonant inductor.

[0010] Preferably, the DC power supply is connected in series with a power switch, and the power switch, resonance control switch, discharge control switch and charge control switch are all semiconductor switches.

[0011] Preferably, when the Marx generator is in the charging stage, the charging control switch is turned on, the DC power supply charges the capacitor of the resonance compensation unit and the capacitor of the common unit, and the power switch, the resonance control switch and the discharge control switch are all in the off state.

[0012] Preferably, when the Marx generator is charged, the charging control switch is turned off, the discharge control switch is still in the off state, and the resonance control switch is turned on so that the capacitor and the resonant inductor of the resonance compensation unit form a resonant circuit, and each resonance compensation unit starts its own single resonance process.

[0013] Preferably, when the Marx generator is in the discharge stage, after the resonance starts for td time, the discharge control switch is turned on, and the capacitor of the resonance compensation unit is connected in series with the capacitor of the common unit to discharge the load, thereby achieving compensation for the discharge waveform.

[0014] Preferably, when the discharge control switch is turned off, the resonant control switch is turned off, the freewheeling diode of the resonant control switch will ensure the continuity of the current, and the energy on the resonant inductor will return to the capacitor through the anti-parallel body diode.

[0015] Preferably, when the discharge control switch is turned off, the charge control switch is turned on again, and the discharge pulse waveform is "truncated". At the same time, the circuit enters the next working cycle and starts charging. The "truncation" can speed up the trailing edge of the discharge pulse. When to perform the "truncation" is determined by the dead time between the shutdown signal of the discharge control switch and the turn-on signal of the charge control switch.

[0016] Preferably, the Marx generator is one of a Marx generator that outputs positive polarity pulses, a Marx generator that outputs negative polarity pulses, or a Marx generator that outputs positive and negative bipolar pulses.

[0017] Compared with the prior art, the present invention has the following beneficial effects: by precisely controlling different switches, it compensates for pulse voltage droop under different loads and pulse widths. By using an appropriate number of compensation units, the number or capacity of main capacitors can be significantly reduced, and voltage and current droop on different resistive loads can be flexibly compensated. Furthermore, the compensation units can also operate as ordinary units, making them more economical and flexible than simply increasing the capacitance to reduce voltage droop, avoiding the dramatic increase in cost and volume associated with doubling the capacitance. The resonant circuit-based compensation unit has a simple structure and is easily modularized. No auxiliary DC power supply is required, and since the compensation unit can be installed on the low-voltage side, electrical insulation is easily handled. When the resonant capacitor and the Marx capacitor are selected to have equal capacitance, the resonant inductance only needs to be determined based on the pulse width and frequency requirements. Therefore, the resonant circuit can be easily designed. Furthermore, the resonant circuit-based Marx generator droop compensation system of the present invention also has the advantages of low cost and compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the overall circuit of a positive polarity Marx topology with a resonant compensation unit of a pulse droop compensation circuit of a Marx generator based on a resonant circuit according to the present invention;

[0019] Figure 2 Schematic diagram of a resonance compensation method for a pulse droop compensation circuit of a Marx generator based on a resonance circuit according to the present invention;

[0020] Figure 3 Schematic diagram of a charging working mode of a pulse droop compensation circuit of a Marx generator based on a resonant circuit according to the present invention;

[0021] Figure 4 Schematic diagram of the resonant working mode of the pulse droop compensation circuit of the Marx generator based on the resonant circuit according to the present invention;

[0022] Figure 5 Schematic diagram of the discharge working mode of the pulse droop compensation circuit of the Marx generator based on the resonant circuit according to the present invention;

[0023] Figure 6 The compensation unit of the pulse droop compensation circuit of the Marx generator based on the resonant circuit according to the present invention is used as a discharge working mode of a Marx common unit;

[0024] Figure 7 A schematic diagram of the recharging process and truncation of a pulse droop compensation circuit of a Marx generator based on a resonant circuit according to the present invention;

[0025] Figure 8 The figure is a timing diagram of switch tube signals of a pulse droop compensation circuit of a Marx generator based on a resonant circuit according to the present invention. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Reference Figure 1-8 , a pulse droop compensation circuit of a Marx generator based on a resonant circuit, comprising: at least one resonant compensation unit;

[0028] at least one common unit, the common unit being connected in series with the resonance compensation unit, the common unit comprising at least one diode, a capacitor connected in parallel with the diode, a charge control switch connected in series with the diode, and a discharge control switch connected in series with the charge control switch;

[0029] a DC power supply, the DC power supply being connected in series with the resonant compensation unit and the common unit, and the DC power supply being used to charge the capacitors in the common unit and the compensation unit;

[0030] The load is connected in parallel with the resonant compensation unit and the ordinary unit. The resonant compensation unit is used to discharge the load, and the pulse droop occurring in the discharge pulse is compensated to varying degrees by controlling the number of compensation units. When the load resistance is high, the voltage droop can be ignored and no compensation is required. In this case, the compensation unit can be used to increase the output voltage.

[0031] Furthermore, the resonant compensation unit includes all components of the ordinary unit, at least one resonant inductor connected in parallel with the capacitor, and a resonant control switch connected in series with the resonant inductor. The resonant control switch of the resonant compensation unit is always disconnected and no resonance is generated. All resonant compensation units discharge to the load like ordinary units, or some resonant compensation units participate in discharging to the load, which can be used to increase the output voltage amplitude. According to the actual magnitude of the pulse drop, it can be selected to allow only a part of the resonant compensation units to resonate, and the remaining resonant compensation units discharge to the load like ordinary units, or all the resonant compensation units resonate to compensate for the output pulse, thereby adjusting the degree of compensation.

[0032] Furthermore, the DC power supply is connected in series with a power switch, and the power switch, resonance control switch, discharge control switch and charge control switch are all semiconductor switches.

[0033] Furthermore, when the Marx generator is in the charging stage, the charging control switch is turned on, the DC power supply charges the capacitor of the resonance compensation unit and the capacitor of the common unit, and the power switch, the resonance control switch and the discharge control switch are all in the off state.

[0034] Furthermore, when the Marx generator is charged, the charging control switch is turned off, the discharge control switch is still in the off state, and the resonance control switch is turned on so that the capacitor and the resonant inductor of the resonance compensation unit form a resonant circuit, and each resonance compensation unit starts its own single resonance process.

[0035] Furthermore, before discharge, after the resonant compensation unit is allowed to resonate, any portion of the sinusoidal oscillation voltage on the capacitor in the resonant compensation unit is connected in series to the discharge pulse at the appropriate time, thereby superimposing the output pulse of the series discharge of the ordinary unit and outputting a different pulse waveform. If the nearly linear portion of the sinusoidal oscillation voltage is connected in series with the ordinary unit, the pulse droop can be compensated and reduced. When the Marx generator is in the discharge phase, after the resonance starts td time, the discharge control switch is turned on, and the capacitor of the resonant compensation unit is connected in series with the capacitor of the ordinary unit to discharge the load, thereby compensating for the discharge waveform. The resonance process continues during the discharge phase, so the nearly linearly growing resonant capacitor voltage can be applied to the discharge pulse to compensate for the output waveform.

[0036] Furthermore, when the discharge control switch is turned off, the resonant control switch is turned off, and the freewheeling diode of the resonant control switch will ensure the continuity of the current. The energy on the resonant inductor will return to the capacitor through the anti-parallel body diode.

[0037] Furthermore, when the discharge control switch is turned off, the charge control switch is turned on again, and the discharge pulse waveform is "truncated". At the same time, the circuit enters the next working cycle and starts charging. "Truncation" can speed up the trailing edge of the discharge pulse. When to perform "truncation" is determined by the dead time between the shutdown signal of the discharge control switch and the turn-on signal of the charge control switch.

[0038] Furthermore, the Marx generator is one of a Marx generator that outputs positive polarity pulses, a Marx generator that outputs negative polarity pulses, or a Marx generator that outputs positive and negative bipolar pulses.

[0039] like Figure 1 As shown in the figure, the entire circuit consists of two parts: the resonant compensation unit and the Marx circuit. Both circuits can be modularized and stacked in multiple stages. Each resonant compensation unit consists of a resonant control switch, a charge control switch, a discharge control switch, a diode, a capacitor, and an inductor, while each Marx circuit consists of a charge control switch, a discharge control switch, a diode, and a capacitor.

[0040] like Figure 2 As shown, the nearly linear part of the resonant voltage waveform is utilized to start the discharge pulse at zero resonant voltage, and the required resonant voltage is added to the discharge pulse, thereby compensating for the voltage drop that occurs in the discharge pulse.

[0041] like Figure 3 As shown in the figure, during the charging phase, the charging control switches Qdc, Qri, and Qari are turned on, and the DC source charges capacitors Cri and Ci. The remaining switches are turned off. Here, the resonant compensation unit's capacitor Cri does not require an additional auxiliary power supply to charge it. Instead, it is charged in parallel with the Marx circuit's capacitor Ci, requiring only a single DC source. During the charging phase, the voltage across the load is negligible compared to the high-voltage output pulses.

[0042] When all capacitors are charged to Vdc, the charging control switch is turned off, the discharging control switch is still in the off state, and the resonant control switch Qri is turned on, so that Cri and Lri form a resonant circuit, and each resonant compensation unit starts its own single resonance process.

[0043] When the resonance starts td time later, that is, when the resonant capacitor voltage waveform just crosses the coordinate axis, the discharge control switches Qbri and Qbi are turned on, connecting the capacitor Cri of the resonant compensation unit in series with the capacitor Ci of the Marx circuit to discharge the load and achieve compensation of the discharge waveform. The resonance process continues during the discharge period, so the nearly linearly increasing resonant capacitor voltage can be applied to the discharge pulse to compensate the output waveform.

[0044] When the load resistance is high, the voltage drop can be ignored and no compensation is required. In this case, the compensation unit can be used to increase the output voltage. As long as the switch Qri is not turned on after charging is completed, the compensation unit is equivalent to the ordinary unit of the Marx circuit.

[0045] "Truncation" can make the discharge pulse have a very fast falling edge, and when to perform "truncation" is determined by the dead time between the turn-off signal of the discharge control switch and the turn-on signal of the charge control switch.

[0046] Functions and Effects of the Embodiments

[0047] The droop compensation scheme for a Marx generator based on a resonant circuit provided by the present invention compensates for pulse voltage droop under different loads and pulse widths by precisely controlling different switches. By using an appropriate number of compensation units, the number or capacity of the main capacitors can be significantly reduced, and voltage and current droop on different resistive loads can be flexibly compensated. Furthermore, the compensation units can also operate as ordinary units, making it more economical and flexible than simply increasing the capacitance to reduce voltage droop, thereby avoiding the dramatic increase in cost and volume associated with doubling the capacitance. The resonant circuit-based compensation unit has a simple structure and is easily modularized. No auxiliary DC power supply is required, and since the compensation unit can be provided on the low-voltage side, electrical insulation is easily handled. When the resonant capacitor and the Marx capacitor are selected to have equal capacitance, the resonant inductance only needs to be determined based on the pulse width and frequency requirements. Therefore, the resonant circuit can be easily designed. Furthermore, the resonant circuit-based Marx generator droop compensation scheme of the present invention also has the advantages of low cost and compact structure.

[0048] The number of devices and processing scales described herein are intended to simplify the description of the present invention, and applications, modifications, and variations of the present invention will be apparent to those skilled in the art.

[0049] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A pulse droop compensation circuit for a Marx generator based on a resonant circuit, characterized in that: include: at least one resonance compensation unit; at least one common unit, the common unit being connected in series with the resonance compensation unit, the common unit comprising at least one diode, a capacitor connected in parallel with the diode, a charge control switch connected in series with the diode, and a discharge control switch connected in series with the charge control switch; a DC power supply, the DC power supply being connected in series with the resonant compensation unit and the common unit, and the DC power supply being used to charge the capacitors in the common unit and the compensation unit; A load connected in parallel with the resonant compensation unit and the common unit, wherein the resonant compensation unit is used to discharge the load and to compensate for the pulse droop of the discharge pulse to varying degrees by controlling the number of compensation units; The resonance compensation unit includes all components of a common unit, at least one resonant inductor connected in parallel with the capacitor, and a resonant control switch connected in series with the resonant inductor.

2. The pulse droop compensation circuit of a Marx generator based on a resonant circuit according to claim 1, characterized in that: The DC power supply is connected in series with a power switch, and the power switch, the resonance control switch, the discharge control switch and the charge control switch are all semiconductor switches.

3. The pulse droop compensation circuit of a Marx generator based on a resonant circuit according to claim 2, characterized in that: When the Marx generator is in the charging stage, the charging control switch is turned on, the DC power supply charges the capacitor of the resonance compensation unit and the capacitor of the common unit, and the power switch, the resonance control switch and the discharge control switch are all in the off state.

4. The pulse droop compensation circuit of a Marx generator based on a resonant circuit according to claim 3, characterized in that: When the Marx generator is fully charged, the charging control switch is turned off, the discharging control switch is still in the off state, and the resonance control switch is turned on so that the capacitor and the resonant inductor of the resonance compensation unit form a resonant circuit, and each resonance compensation unit starts its own single resonance process.

5. The pulse droop compensation circuit of a Marx generator based on a resonant circuit according to claim 4, characterized in that: When the Marx generator is in the discharge stage, after the resonance starts td time, the discharge control switch is turned on, and the capacitor of the resonance compensation unit is connected in series with the capacitor of the common unit to discharge the load, thereby compensating the discharge waveform.

6. The pulse droop compensation circuit of a Marx generator based on a resonant circuit according to claim 5, characterized in that: When the discharge control switch is turned off, the resonant control switch is turned off, and the freewheeling diode of the resonant control switch will ensure the continuity of the current. The energy on the resonant inductor will return to the capacitor through the anti-parallel body diode.

7. The pulse droop compensation circuit of a Marx generator based on a resonant circuit according to claim 6, characterized in that: When the discharge control switch is turned off, the charge control switch is turned on again, and the discharge pulse waveform is "truncated". At the same time, the circuit enters the next working cycle and starts charging. "Truncation" can speed up the trailing edge of the discharge pulse. The timing of "truncation" is determined by the dead time between the shutdown signal of the discharge control switch and the conduction signal of the charge control switch.

8. The pulse droop compensation circuit of a Marx generator based on a resonant circuit according to claim 7, characterized in that: The Marx generator is one of a Marx generator that outputs positive polarity pulses, a Marx generator that outputs negative polarity pulses, or a Marx generator that outputs positive and negative bipolar pulses.

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