Pulse Voltage Source Research Articles

The Temperature Dependence of the Parameters of LED Light Source Control Devices Powered by Pulsed Voltage

Ambient temperature has a significant effect on the electrical and luminous parameters of light-emitting diodes (LEDs), which include forward and reverse current, forward voltage, and luminous flux. This paper gives insight into the influence of ambient temperature on the electrical and luminous parameters of LEDs powered by a rectangular pulsed voltage source versus those powered by a constant voltage source. The characteristics of LEDs in LED lighting devices were studied to determine their optimal operating conditions. To this end, rectangular pulse voltages with different pulse filling factors D were considered against the DC voltage source. Characteristics were obtained for the current stabilization mode and for the LED voltage stabilization mode. In both modes, the temperature dependence of the luminous flux, current, voltage, power consumption, and luminous efficiency of the LEDs was studied in the 20 °C to 60 °C range. The optimal LED operating conditions were determined, of which their luminous flux and luminous efficiency are least dependent on ambient temperature. When powered by a rectangular pulse voltage, the LED device drivers’ optimal pulse filling factor and operating frequency were determined.

Multiple Input-Single Output DC-DC Converters Assessment for Low Power Renewable Sources Integration

This paper presents a comparison of Isolated (Flyback) and non-Isolated (Buck) multiple input-single output (MISO) DC-DC converters. The analysis of DC-DC converters is based on pulsed voltage source cells (PVSC). The modeling of both converter types is detailed through their mathematical models and electrical simulations using Matlab/Simulink and PSIM. The comparison focuses on the sizing parameters, non-ideal output characteristics and efficiency. Results show that the output voltage of the MISO Buck converter exhibits a linear dependence on the duty cycles control signal and has slightly higher efficiency than the Flyback converter. To validate the operation of both converters, a scenario with two inputs (low-power hydroelectric and photovoltaic voltage sources) is considered. The modeling and control of both source systems are detailed and the MISO converter performance response is evaluated under sources changes and efficiency point of view.

Presowing Winter Wheat Seed Treatment in the Pulsed Surface Dielectric Barrier Discharge Field

The results from studying indirect treatment of winter wheat seeds in the field of pulsed surface dielectric barrier discharge (SDBD), as well as their treatment in a pulsed electric field (PEF) in different treatment modes and with different treatment duration are presented. The applied pulsed voltage source had capabilities to dose the grain treatment energy by setting the exact number of pulses applied to the electrode system. A weak stimulating effect of SDBD and PEF treatments on individual plant indicators in different modes is shown. A comparison of the seed root length to sprout length ratio by the third day of seed germination demonstrates the best ratio for the PEF mode with a treatment duration of 6.67 s and 0.7 s for SDBD. The newly obtained treatment results are compared with those obtained earlier under the grain treatment conditions in a similar electrode system with a sinusoidal voltage. The comparison results suggest that for achieving better efficiency of combined treatment by electric field and discharge products, a certain ratio of SDBD energy (its intensity) and electric field energy in the gap with the seeds must be kept. To this end, it is necessary to find the optimal parameters of the applied voltage that will ensure the maximum treatment efficiency both in terms of plant germination and minimizing the energy consumption.

Spatial distributions of X-ray radiation during ferrite surface breakdown

Spatial properties of the radiation induced by a ferrite surface flashover supported by a 300 kV and ∼1 ns rise time pulsed voltage source were studied. Peak value and rise time were obtained for the discharge current.

Computer program for modeling of technical state indicators of electromechanical systems

The article is aimed at solving the problem of scientific justification of criteria and methods for assessing the technical state of electromechanical systems based on the topological diagnostic method. Mathematical model and computer program for simulation of technical state indices of asynchronous electric motors (AEM) are presented. Functions and Green matrices, as well as deviation matrices, are considered as such indicators. The basis of the program is the mathematical model of the AEM with a non-accelerated rotor and non-homogeneous windings. AEM is supplied from pulse voltage source. The action is carried out in different directions of the vector space of the motor in order to determine its characteristics and degree of homogeneity. Based on the reactions of the object, the program calculates and analyzes technical indicators for intact and damaged states of the AEM. A computer program for mathematical modeling of the technical state indicators of the AEM was carried out using the Maple package of symbolic and numerical calculations, which provides extensive opportunities for mathematical studies of various levels. A description of a software implementation of the proposed mathematical model is given. An example of using a program to model the performance of a serial motor with specified technical characteristics is given. The article presents the results of modeling the object indicators corresponding to the object different operational states. A reference state, a damaged state characterized by a change in the properties of the vector space during long-term operation, as well as a limit state, which corresponds to a break in one of the phases of the rotor winding, were defined as these states. Conclusions on each of the given electric motor states are given.

KHz Plasma Pencil

Recently several investigators reported on various devices of generating cold plasma jets at atmospheric pressure. A pulsed plasma source developed and reported, the plasma pencil, is one of them. This device is capable of generating a cold plasma plume several centimeters in length using a DC pulsed high voltage source. In this study, kHz alternative current voltage (18 kV-15 kHz) was applied to the electrodes similar to the electrode system of the plasma pencil instead of direct current pulse voltage and a 2-3 cm long plasma jet was produced in an air using the helium gas. This new plasma jet device named as the kHz plasma pencil. The jets produced by the kHz plasma pencil are as cold as room temperature. The optical emission spectrum of the jet of the kHz plasma pencil and the change of the jet length with the gas flow rate have been investigated. Unlike the plasma pencil, the kHz plasma pencil produces jet in two different regimes as filamentary and diffusive and it emits more radiation in the UV range. Preliminary results show that the dynamics of the kHz plasma pencil are also different from the plasma pencil. Keywords: atmospheric pressure cold plasma jet, kHz, plasma pencil, Emission spectrum.

Килогерцевый плазменный карандаш

Recently several investigators reported on various devices of generating cold plasma jets at atmospheric pressure. A pulsed plasma source developed and reported, “the plasma pencil”, is one of them. This device is capable of generating a cold plasma plume several centimeters in length using a DC pulsed high voltage source. In this study, kHz alternative current voltage (18 kV-15 kHz) was applied to the electrodes similar to the electrode system of the plasma pencil instead of direct current pulse voltage and a 2-3 cm long plasma jet was produced in an air using the helium gas. This new plasma jet device named as the “kHz plasma pencil”. The jets produced by the kHz plasma pencil are as cold as room temperature. The optical emission spectrum of the jet of the kHz plasma pencil and the change of the jet length with the gas flow rate have been investigated. Unlike the plasma pencil, the kHz plasma pencil produces jet in two different regimes as filamentary and diffusive and it emits more radiation in the UV range. Preliminary results show that the dynamics of the kHz plasma pencil are also different from the plasma pencil.

Experimental Investigations into Machining Characteristics of Niobium Carbide Cermet with µECM / hybrid laser-µECM.

Niobium carbide (NbC) is a high hardness 1960 (HV30) cermet material which finds applications in the moulds for ceramic injection moulding as well as inserts for cutting tools. This material possesses excellent combination of hardness, toughness and thermal shock resistance. The use of nickel (Ni) binder makes it a promising material for such applications, especially in view of rising cobalt (Co) metal prices used as binder in conventional tungsten carbide (WC-Co) cermet. The tool-wear and tool-failure issues make it difficult for mechanical machining technologies to process this material, especially in the micromachining regime (< 2 mm). To address machinability challenges, electrically conductive Nb cermet has been developed inhouse with Ni as the binder material. This makes it a suitable workpiece candidate for electrochemical machining (ECM) and electrical discharge machining (EDM) processes.Therefore, experimental investigations are presented in this work to evaluate the machining characteristics of NbC cermet with micro-ECM process. Channels have been used as test-features for evaluating machinability. Furthermore, two different grades of NbC cermets have been machined to identify the effect of WC addition on the dissolution characteristics and possible passivation during ECM. A micro-second pulsed voltage source has been utilized for controlled and localized material removal. To further enhance removal mechanisms in terms of processing speed and weakening of passivating layer, the micro-ECM process has been assisted with a nano-second pulsed laser on an in-house developed hybrid machine-tool. The aim is to uniformly dissolve the NbC matrix and Ni binder with ECM process for a high integrity machined surface. The dissolution and passivation characteristics have been further analysed through a combination of current pulse acquisition and channel profile characterisation. Linear sweep voltammetry and channel machining revealed that the addition of WC has a significant impact on the stability of passive layer. Laser assistance could enhance the material removal for both the NbC grades and promote uniform dissolution, with the effect being more pronounced in the NbC grade without WC (41 % increase in average pulse peak current) due to the weaker passive film. The material dissolution was more localized in LECM of NbC grade with WC due to the strong passivation along the channel walls.

Application of a nanosecond corona discharge generator for electrical separation of ores

The use of a pulsed nanosecond voltage source in a corona separator was investigated. Measurements of the distribution of corona discharge current were obtained. The influence of the interelectrode distance on the distribution of the corona discharge current was investigated. Experiments with gold-bearing quartz-sulfide ore and ilmenite ore were carried out. A concentrate was obtained with a gold content of 48 g/t, a mass equal to 18.7% of the original, which corresponds to the extraction of 92% of gold. The titanium content of ilmenite was enriched from 2.87% to 18.1%.

Simulation of Charge Sensitive Preamplifier to improve Nuclear Pulse detecting using Multisim Software

Simulation of Charge Sensitive Preamplifier (CSP) to improve Nuclear Pulse detecting Circuit has been carried on Multisim Software. Multisim Software is a great software that creates the best user-friendly simulation environment for professors, engineers, and students. We can simulate electronic circuits and build prototypes for Printed Circuit Boards (PCBs). In this paper, we have simulated CSP Circuit in two ways. Firstly, by using a pulsed voltage source. Secondly, by using a waveform generator. We have analyzed the behavior of the CSP Circuit with various rise times. The output waveforms have been observed on the oscilloscope.

Traction characteristics modeling of a linear motor for driving an electromagnetic press

The research relevance is connected with the need to improve the calculating methods of the linear press motor used in the drive of the press. As a research object, a cylindrical electromagnetic engine, powered by a pulse voltage source is examined in this paper. The results of the traction characteristics modeling of an electromagnetic motor, which determines the useful mechanical work and the efficiency of the electromagnetic press, are presented here. A simplified model is proposed in the form of an equivalent magnetic circuit of an electromagnetic motor. The calculation is based on the law of the total current for a closed magnetic circuit, depending on the core position coordinate. By solving differential equations of the second order, simple analytical expressions are obtained that allow calculating the electromagnetic traction force depending on the current and the position coordinates of the moving core of the electromagnetic press motor. An example of calculating the traction characteristics of calculating an electromagnetic motor is considered based on the created model. The results of comparing the calculated traction characteristics with the results of calculations obtained by other researchers are also presented.

A Boost Converter-Based High-Voltage Pulsed-Power Supply

This article proposes a new and a generalized topology of high voltage pulse generators for different load conditions. It is modular, reliable, and is capable of generating both unipolar and bipolar pulsed output together with adjustable pulse amplitude, frequency, and width. First, the principle of operation of bipolar high voltage pulsed power source (BHVPPS) is introduced, and thereafter an extensive mathematical analysis is established. Detailed design procedure for the selection of passive components is presented. To verify the established mathematical analysis, a two-stage BHVPPS prototype is designed, and its effectiveness is validated both in powersim (PSIM) simulations and experimentation.

Development and investigations on a hybrid tooling concept for coaxial and concurrent application of electrochemical and laser micromachining processes

In hybrid laser-electrochemical micromachining, both laser and electrochemical process energies act along the same machining axis and thus both influence material removal by their interaction. The traditional nozzle based laser assisted jet-ECM concepts require laser to be focused on workpiece surface in an electrochemical environment and are limited in aspect ratios as the nozzle stays above the workpiece surface. In this work, a hybrid tooling concept is proposed for a novel process scheme of precision hybrid laser-electrochemical micromachining. The tool serves the function of both an ECM electrode as well as a leaky-type multimode waveguide for the laser and delivers laser homogeneously together with the electrolyte on the workpiece surface without requiring laser to be focused on the workpiece surface. A precision prototype hybrid machine-tool is developed which employs short pulsed nano-second laser and micro-second pulsed voltage source for precision micromachining. For this system, ray tracing and detailed multiphysics electrochemical micromachining process simulations are carried out to demonstrate the applicability of this hybrid tooling concept and explain the shape evolution. Successful experimental realization of coaxial and concurrent application of electrochemical and laser processes is presented. Prototype tool electrodes are fabricated and experiments are carried out on an in-house developed prototype hybrid machine tool. The results reveal that the proposed hybrid tool is successfully capable of concentrating laser and electrochemical process energies simultaneously in the same machining zone. However, with the initial design of this hybrid tool, a maximum of 30–40% of laser power is available in the machining zone. Some suggestions for further research will be presented.

Configuration and Digital Simulation of STATCOM utilizing 48-Pulse VSC for Reactive Power Reparation and Potential Reliability

This paper analyzes the configuration of Static Synchronous Compensator-STATCOM utilizing 48 pulse voltage source converter for reactive force reparation and voltage adjustment in force framework transmission and dispersion systems alongside the advanced development of the STATCOM utilizing 48 pulse VSC, expecting framework subjected to unsettling disturbances of real and reactive power. The 48 Pulse voltage source converter is composed with the guide of four 3-level voltage source converters exchanging at the major recurrence to create a sinusoidal yield voltage with decreased symphonies substance. The outline and computerized recreation of STATCOM has been executed in the MATLAB/Simulink stage. It is strongly evident that the outcome of reactive power reparation and voltage stabilization have been substantially improved by the proposed STATCOM configuration with 48 pulse VSC.

Investigation of the characteristics of an ion engine with a microwave generator plasma

This paper presents the results of an experimental study of the velocity of ionized nitrogen flowing from the working chamber of an experimental sample of the primary accelerating system of the ion engine into the vacuum space. The main method of research was chosen calorimetric method. The design of a small spacecraft jet propulsion system with ionized gas acceleration in the high-frequency gap of a microwave generator is proposed. The object of the study is a prototype of the primary ion engine accelerator system with a solid-state microwave plasma generator and an accelerating gap. The study showed that a 3-watt microwave generator together with a pulsed voltage source of an accelerating potential difference of 1 W at a nitrogen consumption of 2.5 mg/s creates an ion jet whose speed reaches 30 km/s.the Current of the ion jet was 2-2.5 mkA. The field strength of the accelerating potential difference was 4450 V / m.

Design of a high-precision and widely tunable bounded-wave electromagnetic pulse simulator

This paper introduces a high-precision and continuously tunable medium bounded-wave electromagnetic pulse simulator, which adopts a widely tunable, automated novel high voltage pulse source of compact size with fast rise time. Based on fiber transmission automation control is realized, anti-jamming problem is solved and HEMP simulation ability is promoted. Parameters of the simulator are: the rise time about 2.5 ns, FWHM about 23 ns, working volume 4 m×4 m×5.8 m, output continuously tunable electric field from 0.2 kV/m to 60 kV/m.

High voltage designed and pulsed electric field circuit using standard sphere-gap method

The circuits designed of the high voltage pulsed source using the sphere-gap as switching and will be used as generating of the high voltage pulsed electric field (PEF). Based on the experiment testing that the high voltage source can produce 80 kV with the efficiency of high voltage DC source is 81.70% and the operating voltage of sphere-gap is 18.5 kV. Therefore, the intensity of the pulsed electric field of the design can be reached at 80 kV/cm. Based on this ranges that design can be used for electroporation process. Furthermore, this tool was tested into a sample, Nematode. For Nematode sample testing, the electric fields strength is E = 37.33 kV/cm on the voltage of between the electrode is 6.7 kV. Thus, the design of the pulsed electric field source using a sphere-gap has functioned.

Dust Particle Synthesis by the Combined Plasma Source at Atmospheric Pressure

In this work, the results of experiments on the dust particle synthesis process by combining two types of discharges at atmospheric pressure are presented. The experimental setup consists of two pin type copper electrodes connected to the pulsed high voltage source (spark discharge) and two copper foils wrapped around a quartz tube powered by a kilohertz high voltage sinusoidal signal [atmospheric pressure plasma jet (APP jet)]. In that case, the spark discharge serves as a precursor. It is a source of vapor and primary nanoparticles. Furthermore, these nanoparticles transported by gas flow to the region of uniform dielectric barrier discharge of the plasma jet increased in size and settled on the surface of the substrate. The results of experiments with combined discharge and with spark discharge only are compared. Particle formation and growth mechanisms were discussed. The chemical composition of the deposited particles was obtained.

Modernization of a frequency-controlled asynchronous electric drive system

The paper introduces the results of mathematical simulation of the operating modes of an asynchronous motor when powered by a sinusoidal voltage source and a width-modulated voltage pulse source. The study shows the possibilities of increasing the energy efficiency of an asynchronous electric drive. Findings of research show the feasibility of studying the switching of the motor power source from a pulse width-modulated voltage to a sinusoidal voltage source in the nominal operating mode in order to increase the energy efficiency of the electric drive

A Physical Calibrator for Partial Discharge Meters

This article offers an alternative method of calibrating partial discharge meters for research and teaching purposes. Most current modern calibrators are implemented as precise voltage pulse sources with a coupling capacitor. However, our calibrator is based on the physical principles of dielectric materials distributed in a plane or space. Calibrator design is unique and there is an attempt to get closer to the behavior of the measured real objects. The calibration impulses are created by energy from a high voltage power supply at the specific or nominal value of the applied voltage. At the same time, it is possible to simulate the value and quantity of the discharges and their position in the object relative to the input electrodes. The calibrator creates conditions as a real measured object with adjustable parameters. This paper describes a design of this type of calibrator, its implementation, numerical simulation of discharge values and laboratory measurements with functional verification using the Tettex 9520 calibrator and galvanic measured system DDX 7000/8003 and DDX 9121b. All measurements are carried out using the CVVOZEPowerLab Research Infrastructure equipment.