High Voltage Trigger Research Articles

A compact solid-state high repetition rate trigger based on a spiral generator.

The trigger generator made with a spiral generator (SG) has the advantages of light weight, compact structure, and low cost and has promising applications in the pulsed power field. This paper introduces a compact solid-state high-voltage pulse trigger system based on an improved SG, which has improved repetition rate and lowered the demands for semiconductor switches' maximum current and current rise rate when compared with previous studies. The improvement is achieved by winding outward an additional layer of the passive layer and low-voltage metal strip, which realizes a significant reduction of the peak current and current rise rate of the discharge switch. The final dimension of the trigger is 25 × 10 × 10cm3, excluding the power supply. An experiment carried out in single shot mode shows that the peak value of the output pulse can reach 50kV with a leading edge of 57ns. Repetitive experiments were carried out up to 1kHz, with the peak voltage of the output pulse being 30.5kV, the leading edge being 48ns, and the jitter being 0.84ns. Finally, the generator is used to trigger a gas switch, and it works stably and reliably.

Underwater Arc Discharge Treatment Using a High-Voltage Arc-Robust Supply

Underwater arc discharge is one of the most effective water treatment methods because of the effects of intense shockwaves and high ultraviolet radiations. In this paper, a high-voltage underwater arc discharge system is proposed to study the inactivation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Escherichia coli</i> bacteria, which has an arc-robust feature. It consists of a high-voltage capacitor charger and a discharge circuit. The high-voltage capacitor charger is developed by an LCCL resonant converter to reach a current supply scheme that is inherently protected and robust against arc discharge. The detailed mathematical analysis and the design optimization of the resonant converter are presented. The discharge circuit is developed by a two-step spark gap scheme using an ultrafast highvoltage trigger circuit, providing a reliable system operation independent of the water conductivity. The proposed underwater arc discharge system is applied to 500ml of pollutant water to study the system’s performance on the inactivation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E. Coli</i> bacteria. The proper microbiological tests are carried out, showing the effectiveness of the proposed underwater arc discharge system. The complete inactivation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E. Coli</i> bacteria is achieved in an extremely short treatment time. Moreover, the experimental results are presented, which validate the desired performance of the proposed underwater arc discharge system.

A compact, low jitter, high voltage trigger generator based on fractional-turn ratio saturable pulse transformer and its application.

In this paper, an all-solid-state high voltage trigger generator is developed, which is aimed at triggering a several gigawatts three-electrode spark gap of an intense electron beam accelerator (IEBA). As one of the most important parts for triggering the IEBA precisely, it is developed based on a fractional-turn ratio saturable pulse transformer and a compact six-stage Marx generator. A pulse of rising time 141ns and amplitude 79.6kV is obtained on the 1000 Ω dummy load. The trigger is operated at pulsed repetition frequency over 10Hz for testing its operational stability. The jitter counted from the initial control signal to the falling edge of the pulse is 0.64ns. In addition, experiments of three-minute continuous repetitive operations at 10Hz and higher frequency are carried out. The results show that the trigger generator has high stability even in long-time operations. So far, it successfully applies to the main switch of IEBA with a breakdown voltage of over 500kV, and a total system jitter of 6.7ns is acquired.

A high voltage capacitance measurement method based on alternating coupled signal injection.

As high voltage pulse power capacitors, ceramic capacitors are widely used in high voltage pulse generators, trigger circuits, laser generators, and other fields. The capacitance of ceramic capacitors is closely related to the direct current (DC) bias voltage. However, the current capacitance measurement methods can only achieve a DC bias of 1 kV, which cannot meet the measurement requirements in high voltage environments. This paper proposes a capacitance measurement method that can accurately measure the capacitance under a DC bias of 3 kV. This method decouples the high DC bias voltage and high frequency alternating small signals and realizes low voltage calibration and high voltage isolation. The experimental results show that the proposed method measures the capacitance under a DC bias of 3 kV with a relative error within ±1%, which makes it possible to accurately quantify the capacitance hysteresis deviation in the process of increasing and decreasing back the voltage.

A battery-powered over-voltage triggering method for two-electrode spark gaps in Marx generator.

Triggered gas switches with trigger electrodes, such as three-electrode spark switches and trigatron type spark switches, have been widely used in repetitive operating Marx generators due to their large current flowing capability. However, the ablation of trigger electrodes during repetitive operation is inevitable, which reduces the working life of triggered gas switches. In this paper, we introduced an over-voltage triggering method for two-electrode spark switches by replacing one of the charging inductors of the Marx generator with a pulse generator. The experimental results showed that a high-voltage trigger pulse with an amplitude of 60 kV and a rising speed of 7.65 kV/100 ns was obtained from a single stackable module with a 12 V lithium battery pack as the energy source. Due to the absence of trigger electrodes, the triggering method is beneficial to extend the lifetime of switches and realize a maintenance-free repetitive operating Marx generator.

Remote triggering of air-gap discharge by a femtosecond laser filament and postfilament at distances up to 80 m

We experimentally observed laser-induced remote high-voltage discharge triggering between two needle electrodes with half-a-cm spacing. The discharge was initiated by a 744-nm, 90-fs, 6-mJ laser pulse undergoing filamentation in air. For the direct voltage below the self-breakdown threshold, triggering of air-gap discharge was synchronized with a 10-Hz laser repetition rate and occurred between 40 and 80 m of the propagation path. No discharge guiding was observed. The experimentally registered and simulated remote triggering probability was above 80% in the range of 45–60 m from laser output and about 50% in the range of 60–80 m. The probability decreases as the postfilament hot spot diverges with a simultaneous increase in stochastic laser beam wandering.

Research of pulsed Xenon lamp power supply based on STM32

Novel coronavirus pneumonia affects the health of people all over the world. In this study, UV pulse high-light sterilization technology was used to combat coronavirus. The light source of the ultraviolet pulsed high-light disinfection robot is a kind of high-brightness flash light source using pulsed xenon lamps as the output load. This paper developed a pulsed xenon lamp power supply with a high-voltage pulse synchronous trigger function, a DC charging voltage of 1kV-3kV, an output pulse current range of 1kA-3kA, and a pulse width of 50μS for a pulsed xenon lamp with a 196mm×Φ10mm and a resistivity of 12Ω⋅A1/2. This paper presented the experimental results of charging voltage of 1kV, output pulse current peak value of 1kA, and pulse width of 50μS. The power supply design was based on the phase-shifting voltage regulation mode of UC3825 control power MOS tube, through the sampling isolation module and the closed-loop feedback formed by STM32 control, the energy storage capacitor was linearly charged through the DC voltage sampling and voltage regulation control module; the trigger pulse signal was generated by the SCR switch, and the xenon lamp was turned on and emits flash light after the pulse transformer was boosted. The sample test results verified the feasibility of the power supply design principles and technical solutions.

Rail-gap switch with a multistep high-voltage triggering system.

A rail-gap switch with a multistep triggering system was developed. The rail-gap switch consisted of two rail-like electrodes and a knife-edge electrode parallel to each other. It was assembled from many pieces and filled with unpressurized-flowing dry air. Good alignments between all electrodes were achieved by using a special jig and the knife-edge electrode as the spatial reference. Furthermore, to trigger the rail-gap switch, a multistep triggering system was used. The triggering system consisted of three components: an optical trigger-pulse generator, a slow high-voltage trigger-pulse generator using an ignition coil for a car, and finally, a fast high-voltage trigger-pulse generator using a three-stage Marx generator. The triggering system generated a negative high-voltage trigger pulse of less than -40 kV with a falling speed of -6.6 ± 0.4 kV/ns. The falling speed was fast enough to initiate multichannel discharges in the rail-gap switch. Finally, the rail-gap switch was tested using a test bench consisting of a 0.5-μF capacitor bank charged to 20 kV. The rail-gap switch was triggered by the multistep triggering system robustly with a delay of 180 ns. The delay between the time, when the peak current of the test bench occurred, and the trigger pulse was 890 ns with a jitter of 20 ns, i.e., ∼2% uncertainty in time. The inductance of the rail-gap switch was ∼80 nH obtained from the discharge tests. The rail-gap switch with the multistep high-voltage triggering system is suitable for any pulsed-power systems with current rise times in the order of 1 µs.

Investigation of high-voltage pulse trigger generator based on photo-conductive semiconductor switch

The trigger to generate high-voltage pulse is one of the most important parts in a pulsed-power system, especially for the conduction characteristics of the main switch. However, traditional triggers usually have the drawbacks of large structure and worse long-term working stability, which goes against the demands of pulsed-power system miniaturization and stability. In the paper, a pulse trigger using photo-conductive semiconductor switch was developed, which is of small size, stable performance and steep leading edge of the output pulse rise. It is found that the output trigger pulse rise time is 14 ns, and the jitter of 20 shots is 330 ps. Applying the designed pulsed trigger in a field distortion switch and a triggered vacuum switch, experiments show that the switches could be triggered stably with reduced jitter.

Effect of three-electrode plasma synthetic jet actuator on shock wave control

A three-electrode high-energy plasma synthetic jet (PSJ) actuator was used for shock wave control. This actuator is an enhanced version of the two-electrode actuator as a high-voltage trigger electrode is added to increase the cavity volume and the input energy while retaining a relatively low disruptive voltage. The electrical properties were studied using current-voltage measurements, and the energy consumption was calculated. To assess the jet strength, the penetration of PSJ was compared with empirical values, and the results show that the momentum flux ratio of PSJ for a capacitance of 0.96, 1.6, and 3 μF was approximately equal to 0.6, 1.0, and 1.3, respectively. The interaction of PSJ with shock waves was acquired using high-speed shadowgraph imaging. The shock was generated by a 25° compression ramp in Mach 2 flow, and PSJ actuator was placed up-stream of the compression ramp. Under the action of PSJ, the strength of the shock was notably weakened, and the near-wall part of the shock was entirely eliminated. The results show the good control effect of the three-electrode high-energy PSJ in high-speed flow.

Developing a pulse trigger generator for a three-electrode spark-gap switch in a transversely excited atmospheric CO2 laser.

To improve the probability and stability of breakdown discharge in a three-electrode spark-gap switch for a high-power transversely excited atmospheric CO2 laser and to improve the efficiency of its trigger system, we developed a high-voltage pulse trigger generator based on a two-transistor forward converter topology and a multiple-narrow-pulse trigger method. Our design uses a narrow high-voltage pulse (10 μs) to break down the hyperbaric gas between electrodes of the spark-gap switch; a dry high-voltage transformer is used as a booster; and a sampling and feedback control circuit (mainly consisting of a SG3525 and a CD4098) is designed to monitor the spark-gap switch and control the frequency and the number of output pulses. Our experimental results show that this pulse trigger generator could output high-voltage pulses (number is adjusted) with an amplitude of >38 kV and a width of 10 μs. Compared to a conventional trigger system, our design had a breakdown probability increased by 2.7%, an input power reduced by 1.5 kW, an efficiency increased by 0.12, and a loss reduced by 1.512 kW.

A Flexible Waveform Conditioning Strategy of an Air-Core Pulsed Alternator

As a new type of pulsed power supply, an air-core pulsed alternator concentrates all the functions of energy storage, energy conversion, and power conditioning in one machine. It is also easy to condition the output voltage and current waveforms. These advantages make it a promising compact power supply system for the electrothermal-chemical gun (ETCG). However, the use of multiphase air-core pulsed alternators as the power supply of ETCGs may give rise to problems such as generating high voltage trigger pulse and providing proper voltage and current waveforms. According to the special requirements of ETCGs, a novel circuit topology and a flexible waveform conditioning strategy of an air-core pulsed alternator were proposed. In the initial stage of the discharge process, the two-phase armature windings are connected in series to generate a high voltage pulse to ignite the capillary. The series mode does not need a high-voltage capacitor and its charger to ignite the capillary, which makes the whole system more compact. After the capillary is ignited, the two-phase armature windings are connected in parallel. Adding conditioning inductors and controlling the trigger angles can make the voltage and current waveforms more flexible. The mathematical model of the two-phase air-core pulsed alternator was established to obtain the basic relationship of the variables. Based on the mathematical model and the circuit topology, the performances of the ETCG powered by the alternator using the flexible waveform conditioning strategy were analyzed. The results indicate that with the new strategy of the air-core pulsed alternator it is feasible to provide more flexibility in pulse conditioning than with the conventional strategy.

A Subnanosecond Jitter Trigger Generator Utilizing Trigatron Switch and Avalanche Transistor Circuit

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.

Study on the Performance of High-Voltage Trigger Generators in Pulsed Power Conditioning System

Two-electrode graphite spark gap switch (TGSGS) is used as the main discharge switch and triggered by a reliable trigger generator in pulsed power conditioning system (PPCS). There would be 108 energy modules in PPCS working at the same time. The reliable operating and jitters of the trigger generators will have impact on the PPCSs performance. In this paper, the working modes of the TGSGS are discussed and the performance of trigger generators in PPCS is tested and presented. A protection strategy of the trigger generator in PPCS is introduced, and effect of the blocking capacitor on the trigger pulse transmission is analyzed and tested. The protection strategy of the trigger generator based on blocking capacitor and fuse can effectively prevent the energy anti-irrigation failure when the pulse transformer core saturated. The blocking capacitor has some effect on the trigger pulse transmission, and has the larger capacitance, getting the higher peak amplitude on the cathode of the TGSGS. It is tried to discuss the working characteristics of the thyristors, and proposes a selection reference of the thyristors in this and other similar applications. The combination of analysis and measurement would be useful for the selection of thyristors and other components.

An all solid-state high-voltage ns trigger generator based on magnetic pulse compression and transmission line transformer

Innovative design of an all solid-state high-voltage ns trigger generator, based on magnetic pulse compression and transmission line transformer, is presented. The repetitive trigger pulse generator was developed to trigger a 700 kV trigatron, which has been used to pulse a repetitive intense electron beam accelerator with Tesla transformer charged double pulse forming lines (PFLs). Experimental results show that the trigger pulse generator could produce 180 kV 65 ns duration pulses with a rise time of 20 ns. The repetitive trigger pulses have nice uniform in the voltage waveform. The control time jitter is less then 3 ns. Owing to its good stability and low time jitter, the high-voltage trigger generator is an excellent candidate to trigger the repetitive accelerator.

Characteristics of the GaAs Photoconductive Semiconductor Switch Operated in Linear-Alike Mode

The photoconductive semiconductor switches (PCSSs) have two operating modes, i.e., linear mode and nonlinear mode (also “lock-on” mode). The low bias voltage and high trigger energy are needed when the switch is operated in a linear mode, but the high bias voltage and low trigger energy are needed when the switch is operated in a nonlinear mode. When the GaAs PCSS is triggered under the condition of the low bias voltage and low trigger energy, the on-state characteristic of the switch is similar to that in the linear mode but different from the nonlinear mode. We refer to this mode as “linear-alike mode.” In this paper, a research on the GaAs PCSS triggered by a laser diode in different low bias voltages is reported. The performance of linear-alike mode is analyzed and an equation used to calculate the on-state current is put forward, on the basis of which a method to measure the ionization rate is presented.

Nanosecond-range multi-pulses synchronization based on magnetic switch and saturable pulse transformer

Magnetic switch has been widely used in the field of pulsed power system for its advantages of solid state, high repetition rate, and long lifetime. In this paper, the synchronization of ns-range multi-pulses based on magnetic switch is studied and two kinds of technical methods are proposed. One of which is based on magnetic switches on a communal magnetic core. It was proved that the synchronization accuracy of 3 pulses is about 2 ns. Another proposed method is ns-range multi-pulse synchronization based on saturable pulse transformer and the experimental result showed that the synchronization accuracy of 2 pulses could achieve 2.5 ns. In contrast to other multi-pulse synchronization methods controlled by high-voltage pulse trigger or laser trigger, the synchronization based on magnetic switch and saturable pulse transformer has the advantages of high synchronization accuracy, long lifetime, and exemption from external trigger signals.

CO2激光器高压脉冲触发系统的设计

To trigger the rotated spark switch in a CO2 laser stably and reliably,a high-voltage pulse trigger system is designed and a new method for driving and protecting Insulated Gate Bipolar Transistor(IGBT) is proposed.According to the trigger structure of rotated spark switch in the CO2 laser,a pulsed source which can output 100-500 Hz repetition-rate pulses and a single pulse is developed with the EPM3512 CPLD chip and the IGBT drive circuit with over-current,over-voltage protection and Electromagnetic Compatibility(EMC) design is proposed by a optocoupler HCPL-3120.Besides,the model of a high-voltage pulse transformer is simulated by PSPICE software.Finally,an experimental platform is buit to test the system performance online.Experimental results indicate that the high-voltage pulse trigger system can output high-repetition-rate pulses higher than 38 kV continuously and stably,which satisfies the requirements of the rotated spark switch in the CO2 laser for stability and reliability.

Design and Performance of the ATLAS Muon Detector Control System

Muon detection plays a key role at the Large Hadron Collider. The ATLAS Muon Spectrometer includes Monitored Drift Tubes (MDT) and Cathode Strip Chambers (CSC) for precision momentum measurement in the toroidal magnetic field. Resistive Plate Chambers (RPC) in the barrel region, and Thin Gap Chambers (TGC) in the end-caps, provide the level-1 trigger and a second coordinate used for tracking in conjunction with the MDT.The Detector Control System of each subdetector is required to monitor and safely operate tens of thousand of channels, which are distributed on several subsystems, including low and high voltage power supplies, trigger and front-end electronics, currents and thresholds monitoring, alignment and environmental sensors, gas and electronic infrastructure. The system is also required to provide a level of abstraction for ease of operation as well as expert level actions and detailed analysis of archived data.The hardware architecture and software solutions adopted are shown along with results from the commissioning phase and the routine operation with colliding beams at 3.5 + 3.5 TeV. Design peculiarities of each subsystem and their use to monitor the detector and the accelerator performance are discussed along with the effort for a simple and coherent operation in a running experiment. The material presented can be a base to future test facilities and projects.

Simultaneity of Spark Gap Switch Firing in the Dense Plasma Focus Device

To gain insight into the synchronization, simultaneity, and switching behavior of the individual switch, two TIA-525 Optical/Electrical converters have been recently introduced to DPF experiments at Lawrenceville Plasma Physics (LPP). These electronic devices, attached to two spark gap switches through optical fibers, detect light sampled from the switch firing and convert it to amplified voltage signals. We observed that in terms of simultaneity and synchronization, the firing behavior and quality of the pair of switches monitored are not the same. Some switches, among the twelve that are being used, fired at the trigger voltage within few tens of ns while the others fired much later (after ~1–2 μs) and are triggered at or after the pinch voltage rise. The results from the present work show evidence of pinch voltage triggering the switches. Since the pinch voltage is over three times the voltage of the capacitors, this voltage triggers those capacitors that do not fire during the regular high voltage trigger pulse. This, we suggest, could affect the efficiency of the device as it simply drains the reserved energy in the system. We present results of an empirical study of spark gap switch firing as well as the total current that is followed using the Rogowski coil.