Pulsed Power Conditioning System Research Articles

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.

A Simple Self-Breakdown Sharpening Switch With Low Jitter and Stable Breakdown Voltage

Normally, a three-electrode spark-gap switch is controlled by the application of an external trigger impulse. In this paper, a novel self-breakdown sharpening switch based on the three-electrode spark-gap switch is proposed. However, in this paper, the trigger electrode is connected to ground through a resistor, with the prespark between the trigger and the main electrodes providing the electrons and ions that initiate conduction of the main gap. A prototype sharpening switch with a breakdown voltage of 116.0 kV ± 1.0 kV and a breakdown time of 3.396 μs ± 0.036 μs is described. When compared with a conventional two-electrode spark-gap sharpening switch, the novel sharpening switch has both a more stable breakdown voltage and lower jitter, and the dc breakdown and impulse breakdown characteristics of the two types of switches are presented and compared. When the impedance of the resistor connected to the trigger electrode is high, it is demonstrated that both the value of this resistor and also the type of load have little effect on the characteristics of the novel switch. However, the breakdown voltage of the novel sharpening switch was found to be sensitive to the rise time of the input pulse from the trigger generator. The prototype sharpening switch has a lifetime at least 20 000 shots and is now in use in a major pulsed power conditioning system.

Study on a Magnetic Switch for Pulsed Power Conditioning System

In order to protect the key elements (e.g., Xe flashlamps) from being damaged by the trigger impulse in pulsed power conditioning system (PPCS), a magnetic switch is used for isolating the high-voltage nanosecond impulse. The magnetic switch in PPCS is working along with the initial magnetization curve. The working principle and performance of the magnetic switch in PPCS is presented. Fe-based nanocrystalline is adopted as the material of magnetic core. According to the specific application, the dynamic characteristics of Fe-based nanocrystalline under nanosecond impulses were obtained experimentally. As the magnetization rate increases, the average relative permeability decreases due to magnetic viscosity and eddy current. The measured parameters of unsaturated inductance, saturated inductance, and saturation time are in agreement with the calculation ones. Finally, the experimental results of the magnetic switch in PPCS are presented.

Design and Construction of a Trigger Generator Based on Pulse Transformer for Spark Gap Switch

A two-electrode graphite spark gap switch is used as the main discharge switch and triggered by a reliable trigger generator in a pulsed-power conditioning system. The trigger generator based on resonant charging of a pulse transformer is constructed. An appropriate ratio can be obtained when using resonant charging based on a core-type pulse transformer. The charging time is dependent on the leakage inductance and the capacitance of the primary and secondary capacitors. The stray resistance and magnetizing inductance of the resonant charging circuit have an impact on ratio and energy transmission efficiency. A dry-type pulse transformer with a load of 1.08 nF, an output voltage of more than 130 kV, and a winding ratio of 65 is presented. A self-breakdown three-electrode output switch is used to shorten the rise time of the output impulse. The deviation of the self-breakdown voltage of the self-breakdown three-electrode output switch is much smaller than that of the self-breakdown two-electrode output switch. It assures that the trigger generator has a low jitter of output impulse when a lot of energy modules work simultaneously. The output impulse of the trigger generator with a peak value of more than 120 kV and a rise time of less than 30 ns can trigger the two-electrode graphite spark gap switch reliably.

Analysis and realization of magnetic switch in pulsed power conditioning system

When two-electrode spark gap switches are applied to main discharging circuit of pulsed power conditioning system, trigger generators will be needed. To guarantee triggering reliability and protect other key components in the pulsed power conditioning system, such as pre-ionization branch and xenon lamp, magnetic switch is needed to insulate the high triggering voltage in the main discharging circuit. In this paper, starting from the analysis of the working principle of the discharging circuit, we present the solution of Fe-based nanocrystalline alloy switch. Specifically, we provide the basis of theoretical calculation and the method of material selection for the design and realization of this magnetic switch. Via the performance tests in pulsed power conditioning system, the validity of material selection and parameter design is proved. This paper provides a reference for the engineering design and application of magnetic switches in huge pulsed power systems.

Capacitor Bank Module for a Multimegajoule Energy Storage

Laser megajoule (LMJ) is a laser facility being built by the French nuclear science directorate, Commissariat a l'Energie Atomique. This facility is a large flashlamp pumped laser (1.8-MJ optical output). The pulsed power conditioning system of LMJ is based on a modular design of 480 modules (400-MJ energy capacitor bank). A new capacitor bank module (CBM) for the LMJ power conditioning system has been developed by the Institute of High Current Electronics (IHCE, Tomsk) in collaboration with International Technologies for High Pulsed Power (France). Two such modules were produced and tested in IHCE. The main parts of the CBM are the following: high-voltage power supplies, command control system, air conditioning system, capacitor block, and cables delivering the energy to a load. The parameters of the module are the following: total rated capacitance of 2900 (+4%) muF, charging voltage up to 24 kV, peak current amplitude of 240 kA, peak stored energy up to 864 kJ, pulsewidth at 10% of peak power of 360 mus, dimensions of 2.3 times 1.5 times 2.5 m3, and weight of ~2500 kg. In nominal regime (24-kV charging voltage, 40-m length cables), the energy delivered to flashlamps in each channel is 74 kJ (86% efficiency). No failures were observed in more than 1000 test shots, and all parameters of the CBM are well within the requirements. Detailed description of the module design, performance, and test results are stated in this paper.

Experimental and analytical investigation of a pulsed power conditioning system for magnetic flux compression generators

The pulsed power conditioning system (PPCS) is one of the key enabling technologies for using the energy output of a magnetic flux compression generator (MFCG). This paper shows the results of comprehensive experimental studies of an inductive energy storage system using an exploding wire fuse. The effects of metal oxide varistors (MOVs) for use as pulse-shaping devices are also presented. The experimental results are complemented by a comprehensive evaluation and interpretation of the results using the tools available in the professional version of MathCAD.

Compact pulsed transformer power conditioning system for generating high voltage, high energy, rapid risetime pulses

Compact, lightweight air-core pulse transformers in open air have been developed. A SHIVA Star capacitor bank module (36 mu F, 120 kV, 260 kJ) was used to drive a transformer for generating high-voltage pulses into resistive loads. Voltages reaching 400 kV were delivered to a 6 Omega load at a total energy delivery of 60 kJ to the load. In order to achieve single high energy pulses to the load, several fused primary concepts were investigated and developed. These concepts along with transformer construction and first-order models of the system are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>