High Peak Voltage Research Articles

Tuning plasma chemistry by various excitation mechanisms for the H2O2 production of atmospheric pressure plasma jets

Abstract Atmospheric pressure plasmas (APPJs) are widely used for research purposes or industrial applications. There are plenty of different APPJs designed with various geometries and excitation frequencies ranging from kHz over RF (MHz) to fast ns pulses. A direct comparison of these APPJs is often challenging as the different geometries or the different excitation frequencies are not the same and can strongly influence plasma behaviour. In this work, this challenge is met and overcome by the use of an APPJ which can be operated at various excitation frequencies. kHz pulsing with a high voltage peak with µs rise time, sinusoidal voltage pulse at 13.56 MHz and fast high voltage ns pulse were applied to the plasma jet used. The production of H 2 O 2 was investigated by treating liquids and measuring the H 2 O 2 concentration in the treated liquid. Fast ns pulses and RF excitation show similar results, while the kHz excitation is less effective in the H 2 O 2 production.

Electrode-based floating treatment wetlands: Insights into design operation factors influencing bioenergy generation and treatment performance

Exponential increases in energy consumption and wastewater have often irreversible environmental impacts. As a result, bio-electrochemical devices like microbial fuel cells (MFCs), which convert chemical energy in organic matter to electricity using exoelectrogenic bacteria, have gained interest. However, operational factors affecting efficiency and energy output need further study. This research investigated bioenergy production and COD, TN, and TP removal in mesoscale floating treatment wetlands (FTW-MFC) using Phragmites australis, Iris pseudacorus, and a mix of both. The Iris FTW-MFC achieved a high voltage peak of 2100 mV. The maximum power densities of 484 mW/m2, 1196 mW/m2, and 441 mW/m2 were observed for Phragmites, Iris, and mixed FTW-MFCs, respectively. Despite promising bioenergy yields, pollutant removal was unsatisfactory. A low area/height ratio (0.38 m2/0.8 m) and high loading rate (18.1 g/m2·d COD) boosted bioenergy output but hindered treatment performance and stressed plants, causing root decay. No significant pollutant removal differences were found between FTW-MFC and FTW. Higher relative plant growth rates occurred in the FTW-MFC. Microbial analysis shown that representatives of Pseudomonas and Clostridium species were consistently found across all samples, involved in both organic compound transformation and electricity generation, contributed to successful microscale results. A supporting microscale MFC experiment showed wastewater composition's impact on bioenergy yield and pollutant removal. Pre-inoculated reactors improved organic matter transformation and electricity generation, while aeration increased voltage and treatment performance. The role of plants requires further verification in future experiments.

Laser-induced transverse voltage effect in c-axis inclined La x Sr1−x TiO3 thin films prepared by MOCVD

Light and thermal detectors based on the laser-induced transverse voltage (LITV) effect have garnered significant interest for their rapid and broad spectral response. In this study, we prepared the La-doped SrTiO3 (STO) epitaxial thin films on the 12° inclined single crystal LaAlO3 (LAO) (100) substrates using our home-designed metal–organic chemical vapor deposition system. Under the illumination of a 248 nm laser, the LITV signals of La x Sr1−x TiO3 films were observed and showed dependence on the La doping level, which can be explained by the changes in the light absorption coefficient, thermal conductivity, and optical penetration depth. The optimized LITV signal was observed with a peak voltage of 23.25 V and a decay time of 106 ns under the laser power density of 1.0 mJ mm−2. The high peak voltage and fast response time of La x Sr1−x TiO3 show great potential in the field of light and thermal detection.

Ultrafast Metal-Free Microsupercapacitor Arrays Directly Store Instantaneous High-Voltage Electricity from Mechanical Energy Harvesters.

Harvesting renewable mechanical energy is envisioned as a promising and sustainable way for power generation. Many recent mechanical energy harvesters are able to produce instantaneous (pulsed) electricity with a high peak voltage of over 100 V. However, directly storing such irregular high-voltage pulse electricity remains a great challenge. The use of extra power management components can boost storage efficiency but increase system complexity. Here utilizing the conducting polymer PEDOT:PSS, high-rate metal-free micro-supercapacitor (MSC) arrays are successfully fabricated for direct high-efficiency storage of high-voltage pulse electricity. Within an area of 2.4 × 3.4cm2 on various paper substrates, large-scale MSC arrays (comprising up to 100 cells) can be printed to deliver a working voltage window of 160V at an ultrahigh scan rate up to 30V s-1. The ultrahigh rate capability enables the MSC arrays to quickly capture and efficiently store the high-voltage (≈150V) pulse electricity produced by a droplet-based electricity generator at a high efficiency of 62%, significantly higher than that (<2%) of the batteries or capacitors demonstrated in the literature. Moreover, the compact and metal-free features make these MSC arrays excellent candidates for sustainable high-performance energy storage in self-charging power systems.

High Frequency Modeling of Electric Machines Using Finite Element Analysis Derived Data

The use of wide band gap semiconductor switching devices in electric machine drives leads to a significant increase in power density and efficiency compared to conventional silicon-based solutions. However, this technology also presents challenges for the insulation design of electric machines since partial discharges (PDs) may occur due to high peak voltage stress as a result of fast and high frequency switching. To evaluate the risk of PD, it is necessary to understand the voltage distribution within the windings and associated insulation of an electric machine during converter operation. To this end a suitable high frequency model of the machine windings capable of predicting the internal voltage distribution is required. This paper proposes a method of constructing such a model based on finite element analysis (FEA) derived data. The FEA data used to parameterise the model in this work incorporates frequency dependant properties and homogenisation techniques to produce data which captures the high frequency behaviour of the machine. The developed model is compared with measurements in both frequency and time domains, demonstrating the utility and accuracy of the model.

Low ON-Resistance and High Peak Voltage Transmission Efficiency Based on High-Purity 4H-SiC Photoconductive Semiconductor Switch

Low ON-Resistance and High Peak Voltage Transmission Efficiency Based on High-Purity 4H-SiC Photoconductive Semiconductor Switch

Phenol decomposition by gas–liquid phase discharge treatment with different metal electrodes: A comparison study

In recent years, non-thermal plasma technology as an advanced oxidation process has received increasing attention for wastewater treatment. In previous studies, the discussion about the effects caused by different metal electrodes in the plasma treatment system is limited. In this work, phenol degradation efficiency and H2O2 formation with Al, Ti, Fe, Ni, Cu, W, and Mo electrodes were investigated. The use of Fe, Ni, and Al electrodes results in higher phenol removal, than that using W, Cu, Mo, and Ti electrodes. After 70 min of discharge treatment, phenol was continuously decomposed in the solution in the Fe, Cu, and Mo electrodes systems. High peak voltage promoted phenol degradation and H2O2 generation, especially for Fe, Ti and Ni electrodes. The alkaline condition is more conducive to phenol degradation than the neutral and acidic conditions regardless of the electrode type. Fe, Al, Cu, and Ni electrodes are affected more by the adjustment of the conductivity with Cl− than that with SO42−. The dominant influence on H2O2 production and decomposition could be attributed to the catalysis of metal particles and metal ions produced by electrode erosion. According to the radical quenching experiments, the main radicals in the degradation of phenol when using each electrode material were analyzed.

Design and Experiment of a Three Phase Two Switches Voltage Clamping Buck PFC

A new three‐phase two‐switch voltage clamping buck Power Factor Correction (PFC) is presents in this paper. The principle and equations of operations are described in detail. Based on the volt‐second balance principle of input inductance in the new converter, this paper gives the design method of the circuit's key components, with voltage and current stresses analyzed. On the basis of the theory above, a prototype with parameters of a 5 kW is designed. Problems of extremely high switch peak voltage stress in the conventional one are solved. The manufacturing cost of high power three phase rectifier has been significantly decreased. A 5 kW experimental prototype with unity power factor, 4.4% input line current THD, 200 Vdc output, and system efficiency of 96% at full load under 380 Vrms input line‐to‐line voltage has been successfully implemented. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Modelling activity in support of MITICA high voltage system protections

MITICA, the full-scale prototype of ITER Heating Neutral Beam (HNBs), has challenging requirements on its power supplies. In particular its unconventional high voltage system is designed to operate at high power and voltage (up to -1 MV dc and about 54 MW), with many interfaces and high voltage insulation technologies co-existing in a single plant. Moreover, the electrical system must manage frequent breakdowns between the accelerator grids during the operation, creating electrical fast transients characterized by extremely high voltage and current peaks. In the conceptual design phase suitable design provisions were conceived to limit the energy in the grids and to limit the overvoltage on specific components in the case of grids-breakdown. The integration tests of the power supplies showed the capability of the system to generate and sustain voltage as high as 700 kV; at higher voltage the voltage withstanding capability was not confirmed as some breakdowns occurred in the plant. Although the location of the breakdowns has not been identified yet, an impact of such breakdowns was highlighted as a couple of the components of the plant suffered a damage. This paper is focused on the analyses performed for the understanding of the fault occurred on the secondary bushing of the 1 MV insulating transformer dedicated to the supply of the Ion Source and Extraction Power Supply system (ISEPS). An extensive activity of modelling and simulation has been developed for explaining the dynamic occurred. The model is based on the stray parameters of the components, which were not easy to be estimated in the design phase, but which turn out to have relevant effects in local fast transient phenomena. After reaching a full understanding of the phenomena, the models have been used to support the conceptual design of an additional protection system for the transformer, for MITICA but also in view of the ITER installation.

Voltage–Current Characteristic of Free Burning Arcs in SF₆ Alternative Gas Mixtures

Voltage–current characteristics of free burning arcs in SF6 and air have been known for decades. As the demand for an SF6-free solution is increasing, there is an accompanying need to determine arc parameters in the alternative gases. An unblown arc experiment has been established to determine the voltage–current characteristics of SF6 alternative gases, which have not yet been thoroughly studied. In this experiment, free burning arc measurements were performed in a number of gases under consideration of SF6 alternatives, including CO2 and mixtures of CO2/O2 with and without C4F7N or C5F10O additives at the concentrations of up to 10 %. Measurements were also performed in air and SF6 for comparison. Arc voltage was measured in each gas at pressures ranging from 1- to 5-bar absolute, and electrode separations ranging from 20 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$95 \mathrm {~mm}$ </tex-math></inline-formula> . Voltage–current characteristic measurements for air and SF6 show good agreement with previously published results. A linear relationship of the arc voltage to the arc length is shown as well as the fourth root dependence of the arc voltage on the gas pressure. It was shown that neither the O2 nor the fluorinated additives to CO2 have any significant influence on the voltage–current characteristic. The minimum arc voltage in all measured gases was slightly higher than in SF6, but the arc in SF6 was the least stable and had the highest elongations resulting in high-voltage peaks. The arc voltage in air had a similar minimum value to the CO2-based gases, but the arc was much more stable, resulting in lower effective voltage, especially at low currents.

Overvoltage Suppression Scheme for Minimized Snubber Requirements in MVDC Solid-State Breakers With Series-Connected IGBTs

Solid-state dc breakers are the ultimate technology for protecting medium-voltage dc grids having equipment vulnerable to excessive fault-current stress, due to the very short fault-clearing times. A typical implementation of such breakers is based on insulated gate bipolar transistors (IGBTs). However, as the rated voltage of the grid increases, series connection of IGBTs is inevitable and impose challenges on transient and steady-state blocking voltage distribution. This article presents a novel voltage-balancing scheme that combines passive resistive-capacitive-diode (RCD) snubber circuits and a gate driver containing a gate-current balancing magnetic-core. The proposed concept aims at minimizing the required snubber capacitances, which may be high. The impact of the proposed configuration on the breaker design and its performance are studied under different fault scenarios. Using the proposed breaker configuration, the snubber capacitance has been reduced by up to 60%. Besides, both simulations and experimental results reveal the mitigation of high peak voltage stress across the early turned-off IGBTs under gate signal propagation delays.

A Three-Phase Active-Front-End Converter System Enabled by 10-kV SiC MOSFETs Aimed at a Solid-State Transformer Application

The use of high-voltage silicon carbide (SiC) devices can eliminate multilevel and cascaded converters and their complicated control strategies, making converter systems simple and reliable. A three-phase two-level voltage-source converter system serves as a simple converter system for interfacing any dc source to a three-phase grid. However, when the high-voltage devices are used in two-level converters, they are exposed to a high-voltage peak stress and a high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$dv/dt$</tex-math></inline-formula> (up to 100 kV/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> s). Operating these semiconductor devices at these stress levels requires careful design not only of the semiconductor die and the module, but also of the gate drivers, busbars, and passive filters. This article demonstrates the operation of 10-kV SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s and discusses the design considerations, advantages, and challenges associated with the operation of the three-phase two-level medium-voltage converter system used as the active-front-end converter system. Reliable operation of the medium-voltage converter system requires the development of reliable high-voltage modules and auxiliary parts, such as gate drivers, busbars, inductors, voltage and current sensors, and proper design of the controller system. Successful tests demonstrating continuous field operation of the medium-voltage active-front-end converter at a nominal rating of 7.2-kV dc-link voltage is demonstrated for the first time in the literature. The results indicate that these devices can accelerate the growth and deployment of medium-voltage SiC devices for field operation, as demonstrated by the operation inside the mobile container.

Achieving high power density of 859.5 mW cm−2: Self-cross-linking polymer membrane based on rigid fluorenone structure

Plasticization of phosphoric acid (PA) leads to deterioration of the mechanical properties of polybenzimidazole membranes. It has been widely accepted that cross-linking is an effective method to improve mechanical properties of membranes. However, cross-linked membranes generally exhibit decreased proton conductivity and poor fuel cell performance. In this work, a self-cross-linking copolymer based on rigid fluorenone-modified polybenzimidazole (FPBI) are designed and synthesized as high-temperature proton exchange membranes for the first time. The cross-linked FPBI membranes are prepared through solvent casting and the cross-linking degrees of the membranes can be controlled by adjusting membrane preparation temperature and evaporation speed of the solvent. The membranes exhibit excellent mechanical properties and high proton conductivities. The membrane with FPBI-80 °C exhibits high oxidation resistance (>80 wt%), PA retention property (>90 wt%), tensile strength (12.08 MPa), and elongation at break (212.7%). The single cell based on FPBI-80 °C exhibits a high open-circuit voltage (1.01 V) and excellent peak power density of 859.5 mW cm−2 at 160 °C in an anhydrous environment. Herein, the FPBI membrane is expected to be applied in high-temperature fuel cells.

Experimental study on the influence of dielectric barrier discharge plasma on the atomization characteristics of aviation kerosene

In order to study the influence law of active particles on atomization characteristics of aviation kerosene and explore the key technologies of plasma application in fuel atomization auxiliary, the dielectric barrier discharge plasma nozzle was independently designed, and the experiments of He plasma jet spectrum diagnosis and fuel atomization characteristic were carried out. The active particle composition of He plasma jet was explored, and the influence of He volume flow rate and peak voltage on electron excitation temperature, SMD and spray cone angle were studied. The results show that He plasma ionizes the air in the surrounding space to produce active particles such as OH, O and He Ⅰ atoms. The electron excitation temperature varies between 3100 and 7300 K and reaches the maximum when the peak voltage is 11 kV. The influence of electric field application and He volume flow changes on the atomization characteristics are very obvious, specifically, as the peak voltage increases, the SMD decreases and the spray cone angle increases. Under the high peak voltage (12–13 kV), the increasing trend of the spray cone angle gradually slows down and stabilizes. As the volume flow of He increases, the SMD decreases and the spray cone angle increases. The difference in oil supply pressure will affect the atomization effect of plasma excited fuel. The specific realization is that under △Pinj = 0.05 MPa, the increase of He volume flow has little effect on the atomization effect. When △Pinj = 0.15–0.35 MPa, the change of peak voltage has a greater impact on SMD, while at a lower △Pinj (0.05–0.25 MPa), the change of peak voltage has a greater impact on the growth trend of the spray cone angle.

Discharge and post-explosion behaviors of electrical explosion of conductors from a single wire to planar wire array

This work deals with an experimental study of a Cu planar wire array (PWA) in air and water under the stored energy 300–1200 J. A single Cu wire is adopted as a controlled trial. Four configurations of PWA and a wire with the same mass (cross-section area) but the different specific surface areas (15–223 cm2 g−1) are exploded. The transient process is analyzed using high-speed photography in combination with the results of optical emission and discharge. Discharge characteristics revealed that PWA always has a higher electric power peak, early but higher voltage peak, as well as faster vaporization and ionization process than the single-wire case. Two to three times stronger optical emission could be obtained when replacing the single-wire with PWA, indicating a higher energy-density state is reached. Phenomenologically, in both air and water, single-wire load tends to develop a transverse stratified structure, while PWA is dominated by the uneven energy deposition among wires. Finally, the synchronism and uniformity of the PWA explosion are discussed.

An All‐Fabric Droplet‐Based Energy Harvester with Topology Optimization

AbstractThe output power density of a triboelectric nanogenerator can be enhanced by several orders of magnitude by a field‐effect transistor like structure. However, the previously reported strip top electrode is not ideal for optimum generation and stable transfer of charges under practical dynamic conditions. Switched on by an impinged droplet, the bridged closed‐loop electric circuit transfers the accumulated charges by converting the conventional interfacial effect into a bulk effect. Randomly falling droplets cannot always exactly impinge the electrode with the desired spreading contact to achieve a high peak voltage, and a large fraction of low‐voltage direct‐contact and sliding‐contact modes will lead to low output and instability. To address this critical challenge, a topology‐optimized droplet energy harvesting fabric (TO‐DEHF) for stable and efficient output from randomly falling droplets is reported. The optimized fabric electrodes in a hexagonal network feature a stable open‐circuit voltage under moving and rotating patterns, threefold over that with the strip electrodes. The peak power density of the TO‐DEHF (71.8 mW m–2) is 4.8‐fold versus the latter (14.8 mW m–2). Moreover, the all‐fabric TO‐DEHF has high flexibility and breathability, based on which a self‐powered wireless wearable prototype is successfully demonstrated for detection of crucial droplet properties, including temperature, pH, and salinity.

Self-Powered Load Sensing Circuitry for Total Knee Replacement.

There has been a significant increase in the number of total knee replacement (TKR) surgeries over the past few years, particularly among active young and elderly people suffering from knee pain. Continuous and optimal monitoring of the load on the knee is highly desirable for designing more reliable knee implants. This paper focuses on designing a smart knee implant consisting of a triboelectric energy harvester and a frontend electronic system to process the harvested signal for monitoring the knee load. The harvester produces an AC signal with peak voltages ranging from 10 V to 150 V at different values of knee cyclic loads. This paper demonstrates the measurement results of a PCB prototype of the frontend electronic system fabricated to verify the functionality and feasibility of the proposed approach for a small range of cycling load. The frontend electronic system consists of a voltage processing unit to attenuate high peak voltages, a rectifier and a regulator to convert the input AC signal into a stabilized DC signal. The DC voltage signal provides biasing for the delta-sigma analog-to-digital converter (ADC). Thus, the output of the triboelectric harvester acts as both the power signal that is rectified/regulated and data signal that is digitized. The power consumption of the proposed PCB design is approximately 5.35 μW. Next, the frontend sensor circuitry is improved to accommodate a wider range of cyclic load. These results demonstrate that triboelectric energy harvesting is a promising technique for self-monitoring the load inside knee implants.

A novel NiCl2-based cathode material for high-voltage thermal battery

NiCl2 is regarded as an ideal cathode material for high-voltage thermal battery. However, the difficulty of preparation and low inherent conductivity have become the major challenge to hinder practical application of NiCl2 material. Herein, the reduced NiCl2 with Ni as conductive agent has been developed via a facile hydrogen reduction. When served as cathode for thermal battery, the NiCl2-based composite exhibits high peak voltage of 2.51 V and short activation time of 0.67 s, accompanying with superior pulse discharge capacity. This work provides a promising alternative for high-voltage cathode and is beneficial to guide the further application of NiCl2 materials.

Functional Electrical Stimulation dengan Pulsa Biphasic Untuk Membantu Fungsi Ekstremitas Atas Pasien Pasca Stroke

Abstract Stroke or nerve function disorders caused by disruption of blood flow to the brain that arises suddenly or quickly with symptoms or signs that correspond to the affected area. One of the post-stroke rehabilitation using electrical stimulation, also known as an electro stimulator. This study aims to design Functional electrical stimulation (FES), which aims to stimulate the peripheral nervous system with biphasic pulses. Stimulation for patients with MMT 1 was optimal at a frequency of 22-30 Hz. In post-stroke patients with MMT inclusion characteristics 0-3, a minimum voltage, frequency and pulse width value of 200 Vp, 22 Hz, and 20 s is required with a power of 0.00146 Watt. Studies have shown that this electro stimulator device had good accuracy and has high peak voltage values and low effective current. It can be considered because it provides comfort and safety for medical therapy equipment.

Snubber Circuit for Marine Controlled-Source Electromagnetic Transmitter

A high-power marine controlled-source electromagnetic transmitter (HP-MCSET) transmits a high-frequency conversion current on the sea floor. Some problems exist when the direct-current to alternating-current (DC-AC) launch bridge (LB) is used in the marine controlled-source electromagnetic transmitter (MCSET). There is a high voltage peak in the LB when the insulated gate bipolar transistor (IGBT) is turned on and off. In some cases, the voltage stress of the IGBT can be exceeded, which may cause IGBT damage. Because the rise of the current steepness is relatively low and the output voltage has a voltage peak in the LB, a snubber circuit is added to the IGBT to suppress the voltage peak to improve the output current and voltage waveform. The suppression of the voltage peaks is analyzed and compared for several groups of snubber circuits. To meet the performance requirements of the MCSET, the optimal snubber circuit is selected to effectively suppress the voltage peaks at an output current of 1 kA. This method is verified by using a 70 kW MCSET and the experimental waveforms are provided. The simulation of the inductance obstruction load in seawater is necessary to determine the conditions for actual marine environment experiments.