High Voltage DC Power Supply Research Articles

Designing of a High Voltage Power Supply for Electrospinning Apparatus Using a High Voltage Flyback Transformer (HVFBT)

Research on nanofiber materials is actively done around the world today. Various types of nanofibers have been synthesized using an electrospinning technique. The most important component when synthesizing nanofibers using the electrospinning technique is a DC high voltage power supply. Some requirements must be fulfilled by the high voltage power supply, i.e., it must be adjustable and its output voltage reaches tens of kilovolts. This paper discusses the design and development of a high voltage power supply using a diode-split transformer (DST)-type high voltage flyback transformer (HVFBT). The DST HVFBT was chosen because of its simplicity, compactness, inexpensiveness, and easiness of finding it. A pulse-width modulation (PWM) circuit with controlling frequency and duty cycle was fed to the DST HVFBT. The high voltage power supply was characterized by the frequency and duty cycle dependences of its output voltage. Experimental results showed that the frequency and duty cycle affect the output voltage. The output voltage could be set from 1 to 18 kV by changing the duty cycle. Therefore, the nanofibers could be synthesized by employing the developed high voltage power supply.

Power supply system for KSTAR neutral beam injector

The power supply system in KSTAR neutral beam injector consists of low voltage and high current DC power supplies for plasma generator of ion source and high voltage and high current DC power supply for accelerator grid system. The arc discharge is initiated by an arc power supply supplying the arc voltage between the chamber wall and 12 filaments which are heated by individual filament power supply. The negative output of arc power supply is common to each positive output of 12 filament power supplies. To interrupt the arc discharging for the fault condition of the arc current unbalance, DCCT current monitor is placed at the positive output cable of the filament power supply. The plasma grid (G1) power supply has the maximum capability of 120kV/70A which consists of low voltage regulator with IGBT-switched chopper array system for the voltage control in unit of 600V and the high voltage rectified transformers to supply DC voltage of 20kV, 30kV, and 50kV. The output voltage of the G1 power supply is also connected to the input of the voltage divider system which supplies the gradient voltage to the gradient grid (G2) in the range of 80–90% of G1 voltage by changing tap of winding resistors in unit of 1%. The charged G1 voltage is turned on and off by the high voltage switch (HVS) system consisting of MOSFET fast semiconductor switches which can immediately be opened less than 1μs when the ion source grid breakdown occurs. The decelerating grid (G3) power supply is inverter system using capacitor-charge power supply to supply maximum −5kV/5A. The important component in power supply system is the surge absorber near the ion source to limit the arc energy deposited to accelerator grid. This paper presents configuration and features of power supply system, main controller, and interlock system of KSTAR NBI.

Gyrotron development at KIT: FULGOR test facility and gyrotron concepts for DEMO

At the Karlsruhe Institute of Technology (KIT), theoretical and experimental foundations for the development of future gyrotrons for fusion applications are being laid down. This includes the construction of the new Fusion Long Pulse Gyrotron Laboratory (FULGOR) test facility as well as physical design studies towards DEMO-compatible gyrotrons. Initially FULGOR will comprise of a 10MW CW power supply, a 5MW water cooling system (upgradeable to 10MW), a superconducting 10T magnet, one or two 2MW ECRH test loads and a new control and data acquisition system for all these elements. The test facility will then be equipped to test the conventional 1MW or coaxial 2MW gyrotrons for DEMO, currently under design, as well as possible upgraded gyrotrons for W7-X and ITER. The design of the new high voltage DC power supply (HVDCPS) is flexible enough to handle gyrotrons with 4MW CW output power (conceivably up to 170GHz), but also test gyrotrons with higher frequencies (>250GHz) which, due to physical limitations in the gyrotron design, will require less power but have more stringent demands on voltage stability.

Low-Ripple and High-Precision High-Voltage DC Power Supply for Pulsed Power Applications

This paper describes the design and implementation of a three-phase resonant converter with low ripple and high control accuracy. Based on a three-phase LCC-type resonant converter-which has advantages of low ripple, highefficiency, and high-power density compared with a single-phase converter-a high-voltage power supply with low ripple (<;0.1%) was designed. In addition to the general merits of an LCC-type resonant converter operating at continuous conduction mode- including soft switching, low conduction loss, and current source characteristics-the proposed scheme uses only one phase under a light-load condition by having different leg designs of the gate drive circuit and snubber parameters. This allows the design to overcome the operational constraints of the general LCC-type resonant converter. The distinctive design of the three-phase converter structure provides high efficiency and low ripple not only during rated operation, but also under light-load conditions. In order to analyze the high performance of the proposed scheme from no load to rated load, a PSPICE simulation was carried out. Comparison results with a conventional LCC-type resonant converter based on a single-phase structure are analyzed from the viewpoints of output ripple, losses, and operable load range. Using the proposed converter, a 20-kV, 20-kW high-voltage dc power supply design and implementation was presented with a superior gate drive circuit. Finally, the superiority of the proposed converter was verified through a simulation and experimental results. It was experimentally confirmed that the developed power supply achieves high performance in terms of efficiency (98%), operable load range (0.5-20 kV), and low ripple (0.05%), with a high power density.

Increased Flame Reactivity of a Lean Premixed Flame Through the Use of a Custom-Built High-Voltage Pulsed Plasma Source

High-voltage (HV) nonthermal pulsed plasma sources at atmospheric pressure are currently studied for combustion enhancement applications. The sub-microsecond electrical discharges produce reactive species that reduce the global activation energy of the combustion processes and increase the flame propagation speed while limiting gas heating. Current pulses of duration <;100 ns are produced through the discharge of a capacitor-charging HV dc power supply. Time-integrated intensified charge-coupled device images, filtered at 430 nm, of a lean premixed CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> /air laminar flame under the influence of pulsed HV electrical discharges are presented as clear evidence of plasma-assisted combustion.

Design and Development of Hand and Foot Contamination Monitor

A hand and foot contamination monitor is a health physics instrument to provide detection and measurement of beta-gamma contamination on the palm of each hand and on the bottom surface of both feet/shoes. There are four channels of detection for two hands and two feet. Four G-M detectors have been used in a single unit to cover the whole area of hand and feet. A regulated high voltage DC power supply (900 V) has been designed using the PIC12F675 microcontroller to operate the pancake Geiger-Muller detectors. The reading is displayed on a linearly scaled 0-100 Bq/cm 2 analog panel meter. The monitor detects beta–gamma radiation emitted by radioactive materials, and if the detected value exceeds a preset level, the monitor sounds an alarm and displays a reading in the respective panel meter. Indicator lamps are used to show the status of contamination. The performance of the system has been tested by using pulse generator and by flat surface radioactive calibration sources. Electronic linearity, detection efficiency, response to the contamination, calibration factor and percentage of error has been measured. Test results were satisfactory and the present system can be used instead of similar imported instruments. Received: 21 May 2014; Revised: 21 August 2014; Accepted: 22 August 2014

The Research of Atmospheric Pressure Cold Plasma Jet Generated by Auto-Excited-Pulsed DC Discharge

In order to obtain stable cold plasma jet under atmospheric pressure condition, we designed a high-voltage DC power supply based on the principle of multilayer piezoelectric ceramic transformer (MPT). At the same time, we developed a cold plasma jet device that its shape is similar to the gun structure. The total weight of device, including the power supply and the generator, is less than 500 g. In the experiments of argon plasma under atmospheric pressure, current–voltage measurements show that the discharge actually appears periodically pulsed with a frequency of about 30 kHz. The discharge current has a pulse-width that is about 100 ns, while its peak value reaches about 32 mA. The maximum length of the plasma is about 3 cm. The further study showed that the discharge current pulse frequency is determined by the ion drift mechanism.

Study on High-Voltage DC Power Supply for Electron Beam Furnace Based on Series Resonance

The high-voltage DC power supply for electron beam furnace belongs to Special Power Supplies. It has the characteristics of high voltage and high power. At present, the high voltage DC power supplies for electron beam furnace are mostly controlled by the silicon controlled rectifier operated by power frequency, which not only has the disadvantages of large volume but also doesn't has the characteristics of anti-short circuit capacity、 rapid protection and restart. This characteristic affects the service life of the electron gun and the quality of the smelting. To solve the above problems, a high frequency resonant converter has been used in high voltage power supply, reduced the volume of power supply and the switching loss, and achieved rapid protection and restart. Simulation and experimental research show that the power supply can meet the requirement of smelting.

Electron gun system for NSC KIPT linac

In the NSC KIPT linac, a neutron source based on a subcritical assembly driven by a 100 MeV/100 kW electron linear accelerator is under design and development. The linear accelerator needs a new high current electron gun. In this paper, the physical design, mechanical fabrication and beam test of this new electron gun are described. The emission current is designed to be higher than 2 A for the pulse width of 3 μs with repetition rate of 50 Hz. The gun will operate with a DC high voltage power supply that can provide a high voltage up to 150 kV. Computer simulations and optimizations have been carried out in the design stage, including the gun geometry and beam transport line. The test results of high voltage conditioning and beam test are presented. The operation status of the electron gun system is also included. The basic test results show that the design, manufacture, and operation of the new electron system are basically successful.

Optimization Design for a High Voltage DC Power Supply Module Based on PSM Technology

Pulse step modulator (PSM) topology is applied to the EAST auxiliary heating system, which consists of a neutral beam injection (NBI) and the related microwave heating system. This paper firstly analyzes the merits and demerits of the traditional PSM modules adopted by other international companies, and then optimizes the topology of the module using the analysis results. Finally, a new topology for the PSM module (a three-phase neutral-point diode-clamped rectifier) is proposed. This new module overcomes the problems of traditional modules and has better cost-effective performance. The experimental results verify that the new module is feasible for engineering applications.

Design and Development of a Power Supply System for NBI Test Stand of EAST

A neutral beam injector (NBI) test stand was constructed to develop a multi-megawatt prototype ion source as an auxiliary heating system on experimental advanced superconducting tokamak. A power supply system for the NBI test stand components such as a set of dc power supplies for plasma generator, a dc high voltage power supply of a tetrode accelerator, a transmission line and a surge energy suppressor. Stable arc discharges of the plasma generator with hydrogen gases for 100 s long pulse have been produced by six Langmuir probes feedback loop regulation mode to control the arc power supply. The 4 MW hydrogen ion beam of 1 s is extracted with beam energy of 80 keV and the beam current of 52 A. The dc high voltage power supply for the plasma grid of the prototype ion source was designed to contribute maximum voltage of 100 kV and current of 100 A. The high voltage power output is continuously adjustable to satisfy with plasma physics experiment in operation frequency of 10 Hz. To prevent damage of the beam source at high voltage breakdown, core snubber using deltamax soft magnetic materials have been adopted to satisfy the input energy into the accelerator from the power supply can be reduced to about 5 J in the case of breakdown at 80 kV. For the transmission line, a disc shape multi cable coaxial configuration was adopted and which the dimension of the diameter is 140 mm at the core snubber. The major issues of discharge characteristics with long pulse and beam extraction with high power for the prototype ion source were investigated on the NBI test stand.

Research on Harmonic Elimination of the DC Circuit

270V high voltage DC power supply system with grid of light weight, uninterrupted power supply and a two power density higher characteristic, in recent years become a hot research topic in domestic and international air supply system.[ To ensure the high voltage DC bus power quality, for the safe operation of the aircraft is very important. Single phase aeronautical static inverter as a typical aircraft power system load, the input current ripple of the serious pollution of the high voltage DC power supply. Therefore, the harmonic pollution problem of how to control the high voltage DC power supply system has been increasingly concerned aviation power researchers.

The Design of High-Voltage Direct Current Power Supply for the Electrical Fast Transient Pulse/Burst Generator

On the basis of introducing the working principle of the electrical fast transient pulse/burst generator, the method of combination of AC inverting and DC boosting is adopted to design a kind of DC high voltage power supply used for the electrical fast transient pulse/burst generator after the further study about the key technology of the high voltage DC power supply according to the requirements of IEC61000-4-4. The experiments show that the power output voltage reaches 5 KV, meanwhile the range of output voltage is from 0.1 KV to 5.0 KV within the linearity is about 5%, the electric power can be up to 250 watts. Above all, the design meets the requirements of the high voltage power supply for the electrical fast transient pulse/burst generator.

Hydrocarbons synthesis from syngas by very high pressure plasma

Experimental studies related to chemical processes based on the use of very high pressure plasma are scarce. In the domain of chemical synthesis enhanced by plasma, the influence of pressure has not been yet reported in literature for conversion of syngas into hydrocarbons. This may be attributed to the difficulties of ignition and sustaining a stable electric discharge at pressures higher than 1MPa. Yet, the use of high pressure plasma could constitute a new route to synthesize hydrocarbons in gaseous phase. Thus, this paper presents experimental results of hydrocarbons synthesis from a syngas having a H2:CO ratio of 2.2:1, i.e. close to the one commonly met in the classical Fischer–Tropsch process, in a tip-tip non-thermal arc discharge reactor at very high pressure (in the range 0.5–15MPa) supplied by a high-voltage DC power supply without any catalyst. The molecular synthesis is here studied through the influence of two process setting parameters: operating pressure and supplying current. The results show that C1–C3 molecules can be synthesized by this way and their concentration significantly varies with the two studied parameters. The best results in terms of products concentration after 60s treatment were obtained: (i) for 12MPa pressure at 0.35A current, with concentration of C1 and C2+C3 around 6000ppm and 90ppm respectively, (ii) for 0.2A current at 0.5MPa pressure, with concentration of C1 and C2+C3 around 4500ppm and 5000ppm respectively. In addition, the energy efficiency of the process was evaluated, based on the determination of specific energies as they are defined in the classical Fischer–Tropsch process. The results demonstrate that the optima in terms of chemical conversion and energy efficiency coincide together.

Study on the Test System of ERF's Performance

Electrorheological fluid (ERF) is a new kind of smart materials, which has a great deal of market value and broad application prospects. To meet the needs of the ERFs performance testing, design and produce of the ERF's performance test system are based on the relationship of the apparent viscosity, shear stress and electric field strength. Select the NDJ-8S digital viscometer, high voltage DC power supply, liquid container, and other parts to constitute the ERFs performance test system after considering the relationship of the apparent viscosity, shear stress, shear rate and electric field strength. The system has potentials to control voltage, change velocity, change the distance between the parallel panels, and test the yield stress of the ERF, shear stress, viscosity and other parameters. The study introduces the hardware and software device, the related experiments, and obtains the relationship of the viscosity, rotational speed, voltage, and plate gap.

Design and Construction of Low Cost High Voltage dc Power Supply for Constant Power Operation

Pulsed load applications like laser based systems need high voltage dc power supplies with better regulation characteristics. This paper presents the design, construction and testing of dc power supply with 1 kV output at 300 W power level. The designed converter has half bridge switched mode power supply (SMPS) configuration with 20 kHz switching. The paper covers the design of half bridge inverter, closed loop control, High frequency transformer and other related electronics. The designed power supply incorporates a low cost OPAMP based feedback controller which is designed using small signal modelling of the converter. The designed converter was constructed and found to work satisfactorily as per the specifications.

Design of high voltage DC power supply based on LCC resonant converter

The aim of this paper is to design a small size, light weight high frequency high voltage (HFHV) power supply. It presents a comprehensive procedure for designing a high output voltage power supply based on series-parallel (LCC) resonant converter, aiming to realize the soft-switching. Through mathematical calculation based on an extensive of the first harmonic analysis, the paper derives the approach of determining the resonant parameters of the LCC converter. Then, a 35 kV power supply featuring a series-parallel resonant converter topology to compensate the distributed parameter is built to verify the correctness of the theory.

Performance and modelling of 70kVdc power supply with solid-state crowbar

The experimental activities of tokamak research involve development of high power RF and microwave sources for fusion related heating and current drive applications. High power RF and microwave tubes like Klystron, Gyrotron and Tetrode are in general operated with high voltage DC power supplies. These HVDC power supplies of the order of 70kVdc, must be equipped with necessary arc fault protection in addition to general over current and over voltage protection.The arc fault protection must act within few microseconds to prevent permanent damage to the RF tube, window, etc. When an arc fault is detected, output voltage of the DC power supply is short circuited using a crowbar device (generally Ignitron, Thyratron, thyristor, rail-gap, etc.) that operates in few microseconds. This diverts the fault current from the load to crowbar device, thereby protecting the load. This is necessary as conventional protection in the power supply input takes ∼100ms to switch-off. The crowbar device must be able to take the fault current till the circuit breaker placed at power supply input is switched off.The arc fault protection is tested for its effectiveness by “wire-burn” test. Full power short circuit of ∼1.5MW DC power supply puts enormous stress on the power supply, utility and the crowbar, therefore frequent wire-burn testing is to be avoided.This report presents simulation of wire-burn test using PSIM software. Optimization of the component values without conducting actual wire-burn test could be achieved.

High Power RF Transmitters for ICRF Applications on EAST

An Ion Cyclotron Range of Frequency (ICRF) system with a radio frequency (RF) power of 4 × 1.5 MW was developed for the Experimental Advanced Superconducting Tokamak (EAST). High RF power transmitters were designed as a part of the research and development (R&D) for an ICRF system with long pulse operation at megawatt levels in a frequency range of 25 MHz to 70 MHz. Studies presented in this paper cover the following parts of the high power transmitter: the three staged high power amplifier, which is composed of a 5 kW wideband solid state amplifier, a 100 kW tetrode drive stage amplifier and a 1.5 MW tetrode final stage amplifier, and the DC high voltage power supply (HVPS). Based on engineering design and static examinations, the RF transmitters were tested using a matched dummy load where an RF output power of 1.5 MW was achieved. The transmitters provide 6 MW RF power in primary phase and will reach a level up to 12 MW after a later upgrade. The transmitters performed successfully in stable operations in EAST and HT-7 devices. Up to 1.8 MW of RF power was injected into plasmas in EAST ICRF heating experiments during the 2010 autumn campaign and plasma performance was greatly improved.

EAST装置ECRH高压直流电源的研究与设计

高压直流电源是ECRH (Electron Cyclotron Resonance Heating)系统最重要的组成部分之一，其工作的稳定性与可靠性直接影响整个系统的运行。本文介绍了一种ECRH高压直流电源的研制方案，用PSM (Pulse Step Modulate)模块电源技术，克服了传统高压电源单机体积大、效率低、网侧低次谐波污染、功率因数低、输出纹波大、动态响应慢等缺点，同时具备1 kHz的调制能力。并通过Simplorer软件仿真和实验，验证了该设计方案的正确性。 High voltage DC power supply is one of the most important parts of ECRH (Electron Cyclotron Resonance Heating) system, and its stability and reliability directly affect the operation of the whole system. The article introduces a design method of ECRH, using PSM (Pulse Step Modulate) module power supply technology, which overcomes the shortcomings of the traditional high voltage power supply, such as large single volume, low efficiency, net side low harmonics pollution, lower power factor, larger output ripple, slower dynamic response and so on. Meanwhile, it has the capacity of 1 KHZ modulation. Furthermore, the simulations of the Simplorer Software and the results of experiment are provided to verify the accuracy of the proposed design method.