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This paper presents the effect of stray capacitances in bipolar (negative and/or positive) pulses generated by the two different topologies of the solid-state Marx modulators. According to the analysis, the stray capacitances influence the energy transfer from the Marx modulator capacitors to the load affecting the bipolar (negative and/or positive) pulse rise time. This paper deals with the structure design to reduce the influence of the stray capacitance and to improve the pulse rise time of these bipolar solid-state Marx modulators. A four-stage laboratory prototype of the two topologies has been assembled using 1200-V insulated gate bipolar transistors and diodes, operating with 1000-V dc input voltage and 1-kHz frequency, producing 4-kV bipolar pulses, with 5- \mu \texts pulse duration and 120-ns rise time, into a resistive load. [ABSTRACT FROM PUBLISHER]

This paper proposes a flyback-circuit-based design of a trigger circuit for a high-power gas switch. By incorporating a flyback circuit in a high-power gas switch, it is possible to generate a high step-up ratio and high-voltage pulse by using a transformer. Furthermore, simple trigger circuit having the minimum possible number of components (transformer and switch) can be realized. When an inductor is used as an energy storage element, energy is stored as a current source, and thus, the element can operate reliably when low impedance exists between the trigger node of the switch after triggering. According to the fundamental operating principle of a flyback circuit, the proposed trigger circuit is designed considering the maximum trigger voltage and energy required for a high-power gas switch. To verify the proposed design procedure and feasibility of the trigger circuit, a compact trigger circuit (7.5 kV, 1.3 mJ/pulse) is simulated using the PSpice program and implemented. Based on this compact circuit, a trigger circuit (20 kV, 100 mJ/pulse) for a triggered vacuum switch (TVS) is developed, and the tests with an actual TVS (3.3 kJ) are carried out. [ABSTRACT FROM AUTHOR]

The multigap gas switch has been widely used in liner transformer drivers (LTDs), but there is still room for improvement on its self-breakdown and triggering characteristics. In this paper, based on the circuit model of the six-gap gas switch, the gap voltage distribution during the charging and triggering process is analyzed, and the optimization on self-breakdown and triggering characteristics by mounting resistors and capacitors in parallel with switch gaps are theoretically and experimentally investigated. The results indicate that compared with the original switch, when the self-breakdown voltage is about ±90 kV, the standard deviation is reduced from 7.5 to less than 3 kV; for a charging voltage of ±80 kV and by operating at 60% working coefficient, when the negative trigger voltage is 75 kV, the jitter of the switch is reduced from 6.1 to 1.4 ns. [ABSTRACT FROM AUTHOR]

This paper describes a high-frequency pulsed-power generator for various industrial applications such as water treatment, food and medical apparatus for sterilization, or polluted gas treatment. The system is made of silicon-controlled rectifier as a main trigger switch, capacitors, two-stage magnetic pulse compression stages, and a linear transformer to generate a maximum of 120-kV, 5-kA pulse. The parameters obtained through the development are: output voltage: 120 kV (maximum), pulse repetition ration: 300 pulse per second, pulsewidth: 0.25~\mu \texts , and mean power: 30 kW. The designed pulsed-power generator is confirmed to be used effectively for many high-voltage pulsed-power applications related to environmental industry by simulation and experiments. [ABSTRACT FROM AUTHOR]

The opening switch is one of the critical technologies in the development of inductive pulsed-power supply. The power requirement is very high when the opening switch is desired to commutate a large current. This paper presents a zero-current opening circuit for inductive pulsed-power supply based on a high-temperature superconducting pulsed-power transformer. First, there are two types of current flowing through the opening switch, one comes from the secondary side of the pulse transformer, and the other one comes from superconducting energy storage inductance. The orientation of the two current is opposite. Then, when the current flowing through the opening switch closes to zero, the switch is opened and this restrains the over-voltage pulse of the opening switch. The simulation results indicate that this zero-current opening circuit is feasible and has potential applications for high-energy systems in the future electromagnetic launcher. [ABSTRACT FROM PUBLISHER]

The meat grinder is a basic circuit for inductive pulsed-power supply (IPPS). Based on meat grinder, the Institute of Advanced Technology proposed a circuit called the slow transfer of energy through capacitive hybrid (STRETCH) meat grinder, in which an Integrated Gate Commutated Thyristors (IGCT) is selected as the main switch. Tsinghua University proposed the STRETCH meat grinder with inverse current commutation with semiconductor devices (ICCOS) in which the main switch is replaced by a thyristor and the ICCOS subcircuit is introduced to turn off the main switch. To reduce the opening switch voltage and increase the current turning-off capacity for IPPS, this paper presents a novel circuit topology named the meat grinder with self-charged capacitor and thyristors (SECTs). The key idea of the SECT topology is to turn off the primary current by the energy transfer capacitor, which is precharged. The meat grinder with SECT has larger capacity than the STRETCH meat grinder because it replaces the IGCT with a thyristor and is simpler than the STRETCH meat grinder with ICCOS because it only needs one capacitor. The suggested circuit is more suitable for IPPS module with high energy density. Simulation and experiment have been carried out to validate the circuit. [ABSTRACT FROM PUBLISHER]

With inherent strengths in energy density and power density, the inductive pulsed power supplies (IPPS) have become an attractive option for the power supplies in electromagnetic launch systems. The meat grinder circuits, including the slow transfer of energy through capacitive hybrid (STRETCH) meat grinder circuit, the STRETCH meat grinder with inverse current commutation with semiconductor devices circuit, and the meat grinder with self-charged capacitor and thyristors circuit, constitute one major branch among the IPPS circuits. This paper summarizes the fundamental research work and contributions of the meat grinder circuits from the perspectives of circuit improvements, performance analysis, inductor design, module collaboration, and efficiency promotion. The future directions of single IPPS module are higher energy level, larger energy density, and higher efficiency. [ABSTRACT FROM PUBLISHER]

The series configuration of fast semiconductor switches seems to be the key component in the high-voltage and fast rising time pulse generation. In this approach, two important issues must be considered. The first is to provide a safe operating condition for the switches in transient intervals. The second is to design a gate drive system with the capability of driving a large number of discrete devices simultaneously. The aim of this paper is to obviate these two requirements. First, different factors affecting the unbalanced voltage sharing between the series switches are discussed. In this investigation, the switch-to-ground parasitic capacitance effect has been recognized as the major effect on the unbalanced voltage sharing in the transient interval. Two schemes for abating this effect are proposed. To solve the unbalanced voltage distribution, the structure with a snubber circuit in the clamp mode operation is suggested. This scheme can be used for any number of switches without destructively affecting their behavior. In addition, the output pulse with a fast rising time could be obtained by the proposed gate drive system. In order to evaluate the operation of the proposed structure, a stacked switch with the voltage capability of 36 kV is tested experimentally. The characteristics of the obtained pulse are the fast rising time (69.5 ns) with the dV/dt of 460 kv/ \mu \texts and the wide range of the pulsewidth adjusting to 0.5–15 \mu \texts . In addition, the voltage variance of the switches level in the series structure is about 10%. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate an influence of high-frequency high-voltage impulse conditioning on the back-to-back capacitor bank switching performance of vacuum interrupters (VIs). Nine identical 7.2-kV VIs were tested by 80 CO operations after the proposed conditioning. Test inrush currents were set to 0-, 2-, and 5-kA peak. The experimental results showed that this conditioning technology could make an impact on both prestrike and restrike characteristics of VIs. The complementary cumulative distribution function (CCDF) of the prestrike gap d\textrm {pre} followed complementary Weibull distribution. In contrast to VIs without conditioning, three typical prestrike gaps, i.e., CCDF 10% prestrike gap d\overline {10} , CCDF 50% prestrike gap d\overline {50} , and CCDF 90% prestrike gap d\overline {90}\vphantom {\sum RRR} , decreased by 39%, 19%, and 4% at most, respectively. Besides, the scattering of d\textrm {pre} decreased by 52% at most. Furthermore, the conditioning technology had an influence on the feature of restrike waveform through variation of field emission current. It could also reduce the restrike probability by 22.5% at most and made the entire restrikes occur between $0.5T$ and $5T$ during recovery voltage period ( $T=20$ ms). [ABSTRACT FROM AUTHOR]

High-performance trigger generators with high amplitude, fast rise time, low jitter are essential for large-scaled pulsed-power systems. Most of the trigger generators are also tiny multistage pulsed-power systems with complicated structures. In this paper, a high-performance trigger generator was proposed by combining the advantages of low-jitter semiconductor switch and high-power gas switch. An avalanche transistor Marx circuit was developed. It was used to trigger a two-stage Marx generator based on trigatron switch. The output characteristics of the Marx circuit based on avalanche transistors and the two-stage Marx generator were studied. The experimental results show that a subnanosecond jitter, nanosecond rise time, high-voltage trigger generator can be achieved by triggering trigatron switch with an avalanche transistor circuit. [ABSTRACT FROM PUBLISHER]

In this paper, the circuit model capable of dealing with magnetizing characteristics of the magnetic cores and switch prefire is established for linear transformer driver (LTD) cavities in PSPICE. Through simulation, the effects of switch prefire on other components in LTD and its output current pulse have been analyzed associated with the variation of energy loss in magnetic cores. Simulation results indicate that a switch prefire in one cavity would produce oscillations added to the charge voltage of the other switches in this cavity and cavities adjacent immediately. The magnitudes of such oscillations have an intimate relation with the magnetic core loss equivalent resistance. The loss equivalent resistances in the range from 4 to 6 \Omega have produced moderate voltage oscillations. Experiments on the 300-kA LTD cavity developed by the Northwest Institute of Nuclear Technology proved that such oscillations added to the charge voltage of other switches are likely to increase the breakdown probability of them. [ABSTRACT FROM PUBLISHER]

This paper presents a novel crowbar system of 10/350-\mu\s pulse current. The crowbar pulse current system includes a crowbar pulse current waveform forming circuit, a controlling unit, and a measuring unit. The crowbar pulse current circuit consists of a main air triggered switch, a triggered vacuum switch (TVS) which is used as the crowbar switch, and two trigger signal generators. A kind of TVS is designed and fabricated. Its triggering characteristics are tested, and experimental results show that, compared with other reported similar switches, the TVS has excellent characteristics such as wide operating voltage scope from 1.3 to 120 kV, short discharging delay time with maximum delay time at 400 ns, and its jitter at \pm10 ns. Based on the TVS, the crowbar 10/350- \mu\s pulse current circuit and its controlling circuit are designed. With a 36-\mu\F storage capacitor C and a 6-\mu\H waveform forming inductance L, a 10/350- \mu\s pulse current waveform with a maximum of 150 kA can be generated. [ABSTRACT FROM AUTHOR]

This paper describes the construction and experimental tests of a 12-kV high-voltage high-action generator based on reverse-switching dynistor (RSD) assembly. The main RSD unit consists of seven 76-mm-diameter dynistor pieces connected in series with a blocking voltage of about 2.4 kV, a magnetic switch based on a 1K101 amorphous alloy core, the trigger system based on a saturable transformer, and a 16-mm RSD assembly; the trigger current could reach 2 kA in amplitude with 1-\mu\s duration under 10 kV. The working voltage rate of this RSD unit is about 8–12 kV. Experiment on a 2.2-mF capacitor test bed under 12 kV working voltage, the switch current amplitude reached 150 kA with 300-\mu\s duration; the transferred charge is about 26.5 C and the action is 2.94 \MA^2\s, respectively. [ABSTRACT FROM AUTHOR]