High repetition rate charging a Marx type generator

O'Loughlin, J.P.; Lehr, J.M.; Loree, D.L.

doi:10.1109/ppps.2001.1002037

Cited by 15 publications

(3 citation statements)

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“…This slightly differs from the empirical relation [2], although the results are comparable. The calculations show that the resistance values necessary for repetitive operations are unrealistic, for example about 225 Ω for a pulse repetition frequency (PRF) of 100 Hz, which is too low to prevent the discharging of the capacitor bank and consequently causes a significant loss of energy during the discharge mode.…”

Section: Simulationcontrasting

confidence: 80%

Study of an Ultra-Compact, Repetitive Marx Generator for High-Power Microwave Applications

et al. 2009

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The need for repetitive high-power microwave systems, for instance within the scope of convoy protection, requires the availability of compact, repetitive pulsed-power generators. The development and the first experimental results of an upgraded balanced ISL Marx generator for future repetitive operations at pulse repetition frequencies in the order of 100 Hz are introduced. A key objective is to keep the fundamental modular coaxial concept by reason of its scalability and compactness. Simulation models were developed under the PSpice software package in order to investigate the charging and discharging phases of the Marx generator and also to determine the design criteria for repetitive operations. The charging resistors were replaced by ultracompact inductors for rapid charging, being able to withstand pulsed voltages up to 60 kV and pulsed currents up to 1.4 kA during the discharge phase. An improved type of strontium-titanate high-voltage ceramic capacitor was successfully tested experimentally up to 70 kV. Each new elementary stage of the Marx generator consists of eight 1.1 nF sectors of a cylinder capacitors mounted in parallel, two charging inductors of about 17.8 µH and two halves of spherical spark gaps. The pressurized self-triggered gas switches are arranged along the axis for fast consecutive breakdown thanks to the UV radiation emitted during the breakdown in each gap. SimulationThe ISL ultracompact Marx generator using charging resistors, an in-depth description can be found here [1], represents the starting point of the development of the repetitive Marx generator.The modeling of the charging phase of a resistive Marx generator shows that the charging time can be described by t ch (N, RC) = aN 2 + bN + c + dRC + e, the formula's coefficients being given by the particular characteristics of the applied power supplies. This slightly differs from the empirical relation [2], although the results are comparable. The calculations show that the resistance values necessary for repetitive operations are unrealistic, for example about 225 Ω for a pulse repetition frequency (PRF) of 100 Hz, which is too low to prevent the discharging of the capacitor bank and consequently causes a significant loss of energy during the discharge mode. Previous experiments with the ISL Marx generator already showed massive problems at values of about 1 kΩ. The last stages did not trigger reliably. This is also due to another problem related to resistive charging, i.e. the single stages are charged asynchronously. Therefore, replacing the resistive elements of the Marx ladder network by charging inductors is imperative for repetitive operation at pulse repetition frequencies of about 100 Hz. * corresponding author; e-mail: rainer.bischoff@isl.eu Figure 1a shows the PSpice simulation scheme for the discharge phase of a balanced 7-stage Marx generator, which also considers the stray capacitors. The results (964)

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Section: Simulationcontrasting

confidence: 80%

Study of an Ultra-Compact, Repetitive Marx Generator for High-Power Microwave Applications

et al. 2009

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“…A Marx generator provides one of the most widely used methods of generating high-voltage impulses because it features a low-voltage power supply for charging and does not require a pulse transformer for the generation of the high voltage [4,5]. The basic Marx generator as shown in figure 1 comprises a number of stages, with each stage made of a discrete capacitor and a switch.…”

Section: Solid-state Marx Generatormentioning

confidence: 99%

Development of an integrated solid-state generator for light inactivation of food-related pathogenic bacteria

Ghasemi

MacGregor

Anderson

et al. 2003

Meas. Sci. Technol.

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This paper is concerned with the design and performance of a fully integrated solid-state Marx generator, which has been developed to drive a UV flashlamp for use in microbiological inactivation. The generator has an output voltage rating of 3 kV and a peak current rating of 2 kA, although the modular approach taken allows for a number of voltage and current ratings to be achieved. The generator is constructed using a number of series-and parallel-connected 1.2 kV insulated-gate-bipolar-transistor (IGBT) switched capacitors. Switching of the IGBT modules is controlled by an optical signal. Details are given of how the optimum IGBT gate-drive circuit is achieved using optical components and a pass-through wire to provide the required energies for individual IGBT modules. The generator is demonstrated as the driver of a UV flashlamp used for inactivation of food-related pathogenic bacteria such as E. coli and Salmonella. The performance of the Marx generator over a period of 10 6 pulses is examined, along with the changes that occur in the spectrum of the UV flashlamp during the same period.

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“…Each stage capacitor is charged in parallel through a series resistance and inductance with mutual coupling as elaborated on by Baum and O'Loughlin. [2,3] For high PRR operation, a high power charging supply must be used. For low PRR or portable operation, a high voltage DC-DC converter can be used to charge the stage capacitors.…”

Section: System Overviewmentioning

confidence: 99%

A compact, low jitter, fast rise time, gas-switched pulse generator system with high pulse repetition rate capability

Focia

Frost

2009

2009 IEEE Pulsed Power Conference

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We present the experimental results of an ongoing research effort focused on the development and refinement of a compact, low jitter, fast rise time, command triggered, high peak power, high pulse repetition rate (PRR), gas-switched pulse generator system. The main component of the system is a gasswitched Marx-like pulse generator module designed for applications including UWB radar, microwave sources, and triggering large scale multi-module pulsed power systems of all types. The pulse generator system, comprised of a single or multiple Marx modules, is command triggered by a single or multiple TTL level pulses generated by a timing and control system implemented using LabVIEW software and a PXI-based hardware system. The TTL trigger pulses fire all solidstate high voltage trigger pulsers that close the first stage switches in the Marx modules using a novel method to reduce jitter. The control system also accepts user input to set the desired output conditions, adjusts the charge voltage of a high voltage capacitor charging power supply, inhibits capacitor charging during firing of the pulse generators, and can control the system in a closedloop fashion to maintain relative timing and output characteristics during timing drifts and changing environmental conditions. The individual Marx stages are compact and stackable and utilize field enhanced spark gap switches. The stage capacitors are charged in parallel through mutually coupled inductors in series with resistors. This charging scheme allows for high PRR operation limited only by the stage switch recovery time and the power of the available capacitor charging power supply. The stage switches are optically coupled to aid in Marx output voltage formation and to minimize system jitter. The Marx generator is housed in a lightweight aluminum pressure vessel and is operated in a low pressure dry air environment. The design exhibits a low inductance which varies depending on the number of stages used. Using a five stage prototype, we have generated output voltages of ~100 kV with a rise time of <4 ns. The output pulse width is variable and is dependent on the value of the Marx stage capacitors used and the load resistance. The pulse generator system has been operated in a burst mode at a PRR in excess of 1 kHz with good output voltage regulation. The total jitter of the Marx generator system, i.e. from the application of the trigger pulse to arrival of the output pulse, was measured and found to be <1 ns. 1227 9781-4244-4065-8/09/$25.00 ©2009 IEEE

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High repetition rate charging a Marx type generator

Cited by 15 publications

References 0 publications

Study of an Ultra-Compact, Repetitive Marx Generator for High-Power Microwave Applications

Study of an Ultra-Compact, Repetitive Marx Generator for High-Power Microwave Applications

Development of an integrated solid-state generator for light inactivation of food-related pathogenic bacteria

A compact, low jitter, fast rise time, gas-switched pulse generator system with high pulse repetition rate capability

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