Pulsed Power Supply Research Articles

Development of a pulsed magnetic field power supply for small size Betatron

In this paper, we present a new structure of capacitor-inductor discharge circuit and develop a pulsed magnetic field power supply for small size Betatron, addressing the urgent need for adjustable pulsed radiation frequencies. The proposed power supply employs insulated gate bipolar transistors (IGBTs) to control the discharge of the energy storage capacitor to the excitation winding, thus generating a pulsed current, which produces a pulsed magnetic field and accelerates the electrons. By adjusting the operating frequency of the IGBTs, the frequency of the pulsed current, and consequently the accelerator pulsed radiation frequency, can be regulated. The proposed design employs dual sustained paths, which are formed by the energy storage capacitor and the excitation winding, as well as a loss-compensation capacitor with the excitation winding. By adjusting the loss-compensation time, the problem of the pulsed current amplitude attenuation due to losses can be overcome, ensuring the stability of the pulsed magnetic field. Experimental results show that the power supply produces a pulsed current up to 220 A, which accelerates the electrons to 6.2 MeV, allowing the accelerator pulsed radiation frequency to be adjusted within a 333-Hz range. The proposed power supply makes small size Betatron suitable for a wide range of applications and provides technical knowledge for other types accelerators.

Design and operation of a repetitive compact torus injector for the EAST tokamak

The design, implementation, and initial operation results of a Compact Torus Injector (CTI) capable of repetitive operation are presented. This CTI is designed to reliably and efficiently inject high-density, self-organized plasmoids into the EAST tokamak for central fueling. To enable repetitive operation, a high-voltage, high-power pulse power supply switched by ignitrons has been installed to trigger Compact Torus (CT) discharges. Through careful design and optimization, repetitive operation at a rate of 2 Hz for 10 CTs has been achieved during bench tests. This CTI will be installed on the EAST tokamak in the future. Various diagnostic devices have been developed to monitor the quality of the CT plasma during repetitive operation. The plasma current, plasma line-averaged density, and edge magnetic field exhibit high reproducibility, whereas the reproducibility of plasma radiation intensity is comparatively lower. The maximum plasma line-averaged density, velocity, and mass of the single CT plasma at the injector exit are 3.04×1021 m−3, 180 km/s, and 226.7μg, respectively, suitable for penetrating into a toroidal field up to 0.91 T. The successful operation of the repetitive CTI advances engineering research for the central fueling of future steady-state fusion reactors.

Retraction: "Water splitting system with a 13.1% solar to hydrogen conversion efficiency using 3-junction III-V solar cells with pulse plated Pt black catalyst"

Retraction The authors hereby retract the above article. This paper reports on a highly efficient system for water splitting using a three-junction solar cell with a platinum black catalyst under simulated sunlight. After this manuscript was accepted, it was found that there was an error in the conditions for electroplating the platinum black catalyst on the solar cell. Specifically, there was an error in the settings for the pulse power supply used when plating platinum black. Although the pulse current, pulse width, and cycle were set correctly, the base current value was the same as the pulse current, which was found in a separate experiment using the same equipment. The authors checked the current output under the conditions described in this manuscript using an oscilloscope, and it was confirmed that it was a direct current, not a pulsed current. The measurement results for hydrogen production under simulated sunlight irradiation presented in the paper were correct, and the conclusions regarding hydrogen production were also correct. However, there was an error in the plating conditions for platinum black described in the paper, and the title and content of the discussion also needed to be revised. Based on the above, the authors reached the consensus that the above paper should be retracted and that the authors will submit it again as a new paper with no mistakes in the Japanese Journal of Applied Physics.

Pulsed power supply of Tr-RC and Tr-RLC topologies for improvement of micro electrical discharge machining

Pulsed power supply is one of the key technologies in micro-electrical discharge machining (micro-EDM), particularly in machining micro-holes with high aspect ratios. Through the disadvantageous waveform feature analysis of the controllable RC pulsed power supply with random interpulse voltage, insufficient capacitor charging, and uncontrolled reversed fluctuations, an improved Tr-RC pulsed power supply with a promoted function is proposed. Discharge pulses with high power density have the potential to synchronously improve machining efficiency and accuracy. Increasing the discharge peak current by optimizing the pulsed-power topology is a feasible means of improving the power density. A pulsed power supply of the Tr-RLC topology introducing an inductor-controlled branch according to Faraday’s law of electromagnetic induction was further proposed based on the improved Tr-RC pulsed power structure. The discharge waveforms of Tr-RLC pulsed power supply achieve an average peak current of 1.3 A with inductance of 20 μH, compared to 0.5 A with Tr-RC pulsed power supply. For machining micro-holes with aspect ratios of 10:1, 20:1, and 30:1, the Tr-RLC pulsed power supply exhibited an efficiency improvement of 25%, 22%, and 17%, respectively, with reduced taper error and a slight decrease in tool wear rate compared to the Tr-RC pulsed power supply.

Research on Analytical Model of Synchronous Discharge of Capacitive Pulsed Power Supply

Research on Analytical Model of Synchronous Discharge of Capacitive Pulsed Power Supply

Stress Calculation and Structure Optimization of the High Energy Density Inductor for Pulse Power Supply

Stress Calculation and Structure Optimization of the High Energy Density Inductor for Pulse Power Supply

Transient turn-on characteristics of Si RBDT and SiC MOSFET under nanosecond current pulse range

With the development of pulse power supplies, solid-state semiconductor switches are required to have fast switching speeds and low losses. Both Reverse blocking diode thyristor (RBDT) and silicon carbide metal oxide semiconductor field effect transistor (SiC MOSFET) have fast turn-on speed, making them suitable candidates for short pulse generator. In this paper, the transient turn-on characteristics of Si RBDT and SiC MOSFET are analyzed theoretically and validated experimentally. Si RBDT and commercial 1.2 kV/81A SiC MOSFET are comparatively investigated in switching current pulse with a rise time of several hundreds of nanoseconds. (1) The anode current of RBDT could rise exponentially because of the latch-up effect of Si RBDT, while the drain current of SiC MOSFET tends to be saturated. (2) Utilizing the current rise time (Trise) to represent the switching speed, SiC MOSFET can switch faster when the current is lower than 400A. With the increase of the current, Si RBDT presents faster turn-on speed and lower switching loss due to the regenerative action of the two coupled transistors. (3) The transient characteristics of Si RBDT include a voltage-controlled inductance, while SiC MOSFET contains a current-controlled inductance based on the current rise time, respectively. With the increasing of the main voltage, the equivalent inductance of Si RBDT decreases and tends to be saturated when the main voltage is higher than half of the breakdown voltage of Si RBDT. For SiC MOSFET, the equivalent inductance increases until the drain current remains stable for a given gate voltage. This paper confirms the advantages of Si RBDT and SiC MOSFET in different situations.

Air disinfection by nanosecond pulsed DBD plasma

Atmospheric pressure dielectric barrier discharge (DBD) plasma is an emerging and promising technique for air disinfection in public environments. Power supply is a crucial factor but it remains unclear about its impacts on the air disinfection performance of plasmas. In this work, a nanosecond (ns) pulsed power supply was applied to drive an in-duct grating-like DBD array to achieve fast single-pass air disinfection. The influence of pulse parameters and environmental factors on both the discharge characteristics and the single-pass bacterial inactivation efficiency were uncovered. At a close relative humidity (RH) level, the efficiency was dominated by the discharge power, namely, specific input energy could serve as the disinfection dose. A higher frequency, shorter pulse rising time, and suitable pulse width are preferred to obtain a higher Z value. The pulsed source was not notably superior to an alternating current source, or even worse at a low voltage frequency at the same discharge power. Airflow humidity was a predominant factor to improve the efficiency and a single-pass efficiency of ∼ 99% and a Z value of 2.2 L/J were achieved under an optimal RH of 50%–60%. This work provides fundamental knowledge of ns-pulsed DBD on discharge characteristics and air disinfection behaviors.

Fast and flexible solid-state linear transformer driver for plasma discharge based on metal oxide semiconductor field effect transistor.

A pulsed power supply with a short rise time and high repetition frequency is favorable to driving diffusive plasma for strongly oxidizing radical (O3, OH) generation and increasing the system's energy efficiency. In this paper, a 10-stage solid-state linear transformer driver (LTD) with a nanosecond rise time is developed to drive plasma for wastewater treatment. To decrease the rise time, a control system with low jitter is developed to improve the synchronization of pulses using an optocoupler isolation chip. A 10-stage LTD with a rise time of 6.2ns is realized in the case that the rise time of the single-stage LTD is 5.4ns. The results show that the LTD can generate pulses on a 300Ω resistive load with a repetition frequency of 10kHz, an amplitude of 8.80kV, an overshoot less than 3.97%, and a reverse overshoot less than 4.82%. The rise time (6.2-33.0ns), the pulse width (35.9-200.0ns), and the fall time (10.5-27.6ns) can be adjusted flexibly and independently by controlling the drive signals of metal oxide semiconductor field effect transistors. The pulsed generator is utilized to drive plasma in the needle-water electrode system. The preliminary experimental results show that the plasma includes abundant oxygen atoms and hydroxyl radicals with high activity, and it is suitable for wastewater treatment.

Performance and painting scheme considerations for the CSNS injection

The accelerator complex of China Spallation Neutron Source (CSNS) consists of an 80 MeV H- Linac and a 1.6 GeV proton rapid cycling synchrotron (RCS). The beam injection is one of the most important issues for the CSNS accelerator complex. In this paper, the injection methods have been comprehensively studied, including phase space painting and H- stripping. By using the design scheme of the anti-correlated painting, the beam power has successfully reached 50 kW. However, some difficulties have been found in the higher power beam commissioning. In order to solve these key problems, flexibility in the CSNS design has been exploited to implement the correlated painting by using the rising current curve of the pulse power supply. The effectiveness of the new method has been verified in the simulation and beam commissioning. By using the new method, the beam power on the target has successfully risen to the design value. Secondly, according to the CSNS beam commissioning experience, based on the present design of the injection system, a new idea is proposed to perform both correlated and anti-correlated painting in the CSNS. By adopting an additional vertical shift bump generated by four additional alternating current (AC) magnets in the injection region, the local orbit can be manipulated to meet the requirement of correlated painting. The new method can not only perform the correlated painting, but also optimize the anti-correlated painting. The simulation study shows that the new method works well, and both correlated and anti-correlated painting methods are well performed.

Tribological properties of aluminum alloy coated with graphene oxide/polyvinyl alcohol composites after micro-arc oxidation

PurposeAluminum alloy is considered an ideal material in aerospace, automobile and other fields because of its lightweight, high specific strength and easy processing. However, low hardness and strength of the surface of aluminum alloys are the main factors that limit their applications. The purpose of this study is to obtain a composite coating with high hardness and lubricating properties by applying GO–PVA over MAO coating.Design/methodology/approachA pulsed bipolar power supply was used as power supply to prepare the micro-arc oxidation (MAO) coating on 6061 aluminum sample. Then a graphene oxide-polyvinyl alcohol (GO–PVA) composite coating was prepared on MAO coating for subsequent experiments. Samples were characterized by Fourier infrared spectroscopy, X-ray diffraction, Raman spectroscopy and thermogravimetric analysis. The friction test is carried out by the relative movement of the copper ball and the aluminum disk on the friction tester.FindingsResults showed that the friction coefficient of MAO samples was reduced by 80% after treated with GO–PVA composite film.Originality/valueThis research has made a certain contribution to the surface hardness and tribological issues involved in the lightweight design of aluminum alloys.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2023-0427/

Design, Construction and Programming of a Low-Cost Pulsed High-Voltage Direct Current Power Supply for the Electrophoretic Deposition of Silicon Carbide Mixed with Graphite and/or Alumina for Thermoelectric Applications

This document describes a proprietary design, construction, programming and testing of a low-cost pulsed high-voltage direct current (HVDC) power supply with an output of 430 V and power of 25 W. The design obtained allows costs to be reduced compared to commercial ones, highlighting that the manufacturing of this HVDC is easy to replicate. To demonstrate the operation of the pulsed power supply prototype, coatings of silicon carbide (SiC) and SiC mixed with graphite (C) and/or alumina (Al2O3) were made using the electrophoretic deposition (EPD) method. After processing, samples underwent a heat treatment at 500 °C to evaluate their thermoelectric (TE) efficiency. The samples were analysed via X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Seebeck coefficient, electrical conductivity and thermal conductivity. The Seebeck coefficient, electrical conductivity and thermal conductivity were measured in a temperature range of 100–500 °C in a nitrogen (N2) atmosphere. The electrical conductivity of the SiC 6C-4Al sample was 0.65 S/cm at 500 °C, while the maximum Seebeck coefficient was 2500 μV/K of the SiC 6C-4Al sample at 200 °C. The thermal conductivity of SiC 6C-4Al was in the range of 0.35–0.37 W/m·K, which was much lower than the SiC sample free of alumina and graphite in the same measured temperature range. In conclusion, the SiC 6C-4Al sample presented the highest figure of merit with a ZT ≈ 0.01.

Effectiveness of Noble Gas Addition for Plasma Synthesis of Ammonia in a Dielectric Barrier Discharge Reactor

Non-thermal plasma driven ammonia synthesis has great potential for future industrial applications due to its low theoretical energy requirements. To achieve technological advancement and environmental sustainability, it is crucial to boost the energy yield in plasma-assisted ammonia synthesis. Therefore, optimizing energy transfer and utilization are key strategies for enhancing energy efficiency. In this study, dielectric barrier discharge driven by a nanosecond pulsed power supply is used to enhance plasma-assisted ammonia synthesis by controlling the energy transfer through the addition of noble gases. It was found that the addition of noble gases changed the plasma characteristics, significantly improved the uniformity of the discharge, and achieved a high energy yield for ammonia synthesis. The effects of additive amounts of argon (Ar) and helium (He), as well as the pulse parameters including the pulse voltage, pulse repetition frequency, pulse width, and pulse rise time on the energy yield of ammonia synthesis are discussed. The inclusion of noble gases expanded the pathway for gas-phase reactions, with the active components of critical reactions examined through optical emission spectra. This analysis revealed an increased presence of both N2+ and N2* particles in the reaction’s rate-limiting step, attributed to the addition of noble gases. Finally, a zero-dimensional (0D) plasma chemical kinetic model was established to investigate the influence of Ar addition on the reaction mechanism of ammonia synthesis.

Temporally resolved measurement of a force induced by a pulsed water-fuelled magnetron sputtering source

A high-speed solenoid-type pulsed valve is applied to a water-fuelled magnetron sputtering thruster, which can lead a compact and neutralizer-free electric propulsion device by generating a thrust due to the ejection of the sputtered target material, in order to minimize the size of the gas feeding system. The pulsed valve is opened for approximately 5 msec and the gaseous water is introduced into the source via a gas line connected to the source. A dc high voltage is firstly applied between the cathode and the anode; then the discharge is sustained for the period in which a gas pressure enough for the discharge is maintained and a change in the discharge mode is observed during the discharge pulse. To investigate the impact of the mode change on the thrust generation, a temporally resolved measurement of the force is equivalently performed by installing a pulsed voltage power supply and by changing the pulse width of the discharge voltage. The results show the temporal reduction of the thrust-to-power ratio during a pulsed discharge due to the nonlinear correlation between ion energy and sputtering yield. It is suggested that the use of a pulsed valve would be useful for downsizing of the electric propulsion system, while an optimization to properly control the gas flow rate is needed for further development.

Analysis of the Crosstalk Interference of Asynchronous Discharge in the Multimodule Inductive Pulsed Power Supply System

Analysis of the Crosstalk Interference of Asynchronous Discharge in the Multimodule Inductive Pulsed Power Supply System

Development of a MHz Pulsed Power Supply for Kicker Magnet in SHINE

Development of a MHz Pulsed Power Supply for Kicker Magnet in SHINE

Significantly enhanced permittivity and suppressed loss of P(VDF-HFP)-based composites by introducing PPy@BT-OH fillers

Polymer-based composites with high dielectric permittivity (high-k) are extensively utilized in embedded capacitors, pulse power supplies and radio frequency filter, etc. However, the enhancement of permittivity often comes at the price of elevated loss, which greatly diminishes the energy conversion efficiency and stability of the device. Herein, we loaded hydroxylated barium titanate (BT-OH) onto polypyrrole nanowire (PPy) to prepare a kind of PPy@BT-OH fillers and further incorporated them into Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) polymer. Gaining from the stronger interfacial polarization effect and the hindrance to the development of conductive network triggered by PPy@BT-OH fillers, a significantly enhanced permittivity of ∼ 209.2 @ 10 kHz accompanied by a relatively low loss (tan δ ∼ 0.14 @ 10 kHz) was simultaneously realized in PPy@BT-OH/P(VDF-HFP) composite with 8 wt% filler contents.

Enhanced energy storage properties of silver niobate antiferroelectric ceramics with A-site Eu3+ substitution and their structural origin

AgNbO3 (AN)-based lead-free antiferroelectric ceramics are widely studied for their use as dielectric capacitor materials. In this study, Eu3+-doped AN ceramics were prepared and the results show that Eu3+ diffused into the AN lattice. The ceramics were formed by M1 and M2 phases coexisting at room temperature, as distinct from the M1 (M: monoclinic) phase of pure AN. Electrical properties and structural characterization showed that the antiferroelectric stability of the ceramics increases with the increase in Eu3+ levels. At room temperature, Ag0.94Eu0.02NbO3 ceramic exhibited a good energy storage density of 5.3 J/cm3 and a high efficiency of 71.9%. When the temperature rises from room temperature to 140 °C, the efficiency of the sample decreases from 80.4% to 67.1% and Wr decreases from 2.1 to 2.0 J/cm3, which indicates that the sample has good temperature stability. The time constant (t0.9) of this sample was less than 60 ns and the power density (PD) was 51.3 MW/cm3, indicating excellent charge–discharge capabilities. This novel ceramic is expected to be used as a new dielectric capacitor material for pulsed power supplies.

Variable repetition rate pulse power supply based on magnetic pulse compression for copper vapor lasers

Variable repetition rate pulse power supply based on magnetic pulse compression for copper vapor lasers

Review of High Voltage Pulsed Power Supplies and Power Electronics in Pulse Power Generation

Recently, pulse-shaped power supplies have become more popular. Pulsed power is versatile and useful as a supply method since it can take several shapes and has many pulse characteristics. The release of electrons, protons, and neutrons from an atom and the synthesis of molecules to generate ions or other molecules require a lot of immediate energy. Pulsed power is needed for decomposition, molecular fusion and material joining, radiation generation (e.g., electrons, lasers, radar), explosive processes for concrete recycling, wastewater and exhaust gas treatment, and material surface treatments. Industrial and environmental applications require pulsed power, which requires efficient and adaptive pulse modulators. Higher-quality repeating pulses are needed for plasma fusion and laser weapons. Marx Generators, Magnetic Pulse Compressors, Pulse Forming Networks, and Multistage Blumlein Lines have several uses. Pulse modulators use spark gap and hydrogen thyratron gas/magnetic switching technologies for their high voltage tolerance and low-rise times. These creatures are inefficient, unreliable, repetitious, and short-lived. These devices are heavy, bulky, and expensive. Solid-state switching technology can replace conventional devices, improving pulse supply. High-frequency switching repeats the pulsed power supply. These items are compact, efficient, affordable, reliable, and durable. Solid-state transistor applications may not meet switch voltage ratings and rise time constraints. Various power electronics configurations can produce solid-state high-voltage pulses.