Hz Power Supply Research Articles

Characterization of Plasma Activated Water Generated from Gliding Arc Discharge and Its Application on Enhancement of Seed Germination of Radish (Raphanus sativus var. longipinnatus)

In recent decades, generation of plasma activated water (PAW) from non-thermal atmospheric pressure plasma sources has received enormous attention due to their diverse applications. The research described in this paper is mainly focused on the preparation and characterisations of PAW produced from gliding arc discharge (GAD) operated with high voltages (9.7 kV, 50 Hz) power supply system and its use in the enhancement of seed germination of radish. The physical and chemical parameters of the PAW are investigated using a multi-parameter probe and UV-visible spectrometer. There are significant differences in physical parameters like pH and conductivity, and chemical parameters like concentration of nitrates, nitrites, ammonia in untreated and PAW. But no significant differences in temperature and total dissolved oxygen (TDO) are found. In order to determine the effects of PAW on seed germination, different germination parameters are calculated on radish (Raphanus sativus) which indicates that PAW can enhance the seed germination of radish.

Investigation of the Change in Hydrophobicity of Polycarbonate in Atmospheric Pressure Dielectric Barrier Discharge (APBDB) Generated with a 50 Hz Power Supply

Dielectric Barrier Discharge (DBD) of disc electrodes with diameter 5 cm and thickness 1 cm of each has been used for treatment of the samples. The discharge was produced at fixed inter-electrode gap of 4.5 cm for the study of effectiveness of treatment on the surface of the Polycarbonates (PCs). After the treatment in varying time periods the hydrophobic properties of sample changed to the hydrophilic. To investigate the effect of plasma treatment, contact angle was measured by using goniometer with water as a testing liquid. Effect on the sample due to treatment time, applied voltage and working gas were studied. Treatment carried out in Argon environment produced better wettability compared to atmospheric air. Aging effect was also studied to see the evolution of the wettability after time elapsed by measuring the contact angle up to one month after the treatment. Contact angle was increased from 39.35° C to 56.4° C, which was still very lower than the contact angle 81.2° of untreated sample.

Numerical Study on the Effect of Low‐Frequency Power Supply on Desulfurization in the Electroslag Remelting Process

In the electroslag remelting (ESR) process, low‐frequency power supply can significantly reduce power consumption and achieve three‐phase balance of power supply. Therefore, a transient coupling model of fluid flow, heat transfer, and component transport in the ESR process, which is coupled to the electromagnetic field calculated using Maxwell 3D software, is established to study the influence of low‐frequency power supply on desulfurization. When a 50 Hz power supply is used, a skin effect is observed in the metal, and the direction of the Lorentz force at the slag/metal interface changes. However, this effect becomes less pronounced with decreasing current frequency. Sulfur is mainly transferred at the electrode tip, and the desulfurization rate is approximately 50%. Electrochemical reactions mainly occur at the electrode tip/slag interface and the metal pool/slag interface. The removal rate of sulfur using direct current (DC) power supply is less than that using an alternating current power supply. The DC reverse polarity power supply leads to higher desulfurization rate than DC straight polarity, which is 74% and 31%, respectively. The sulfur removal rate increases from 81.37% to 84.59% as the frequency decreases from 50 to 2 Hz because of the longer electrochemical reaction time at this lower frequency.

Effect of Different Power Supply Modes on Inclusion in 304L Stainless Steel Electroslag Ingot

The use of low frequency or DC (i.e., direct current) operation in the electroslag remelting process may lead to the electrolysis of some oxides in the slag pool, which will adversely affect the cleanliness of the electroslag ingot. In order to confirm this view, the effect of different power supply modes on the oxygen content and inclusions in electroslag ingot has been studied by adopting the self-designed electroslag remelting furnace as experimental equipment. The pulse heating inert gas fusion-infra-red absorption method is used for analyzing oxygen content. The analysis of non-metallic inclusion is conducted using an automatic SEM (i.e., scanning electron microscope) made by the American ASPEX Company, where the inclusion type and the inclusion size are determined. Results show that the oxygen content in the electroslag ingot increase significantly compared with that in the consumable metal electrode, whether under the frequency of 50 Hz, low-frequency, or DC. When DCSP (i.e., the consumable electrode is connected to the cathode of the DC power supply), DCRP (i.e., the consumable electrode is connected to the anode of the DC power supply), 2 Hz, 10 Hz, and 50 Hz power supply modes are adopted, the oxygen content in electroslag ingot is 155.3 ppm, 100.4 ppm, 75.8 ppm, 66.3 ppm, and 43.2 ppm respectively. With the increase in oxygen content, the number of inclusions in electroslag ingots increases significantly, and the increased inclusions are mainly Al2O3 inclusions. Regardless of the power supply mode, the largest diameter of inclusion is less than 20 μm. The electrolysis of Al2O3 is the direct reason for the increase in oxygen in the electroslag ingot when CaF2-Al2O3 slag is used. With the decrease in frequency, the electrolysis trend increases, and the oxygen content and the number of inclusions also increase. However, most of the inclusions are regenerated with the decrease in metal pool temperature and solidification, so the size is fine.

Application of Plasma Actuator with Two Mesh Electrodes to Active Control of Boundary Layer at 50 Hz Power Supply

Application of Plasma Actuator with Two Mesh Electrodes to Active Control of Boundary Layer at 50 Hz Power Supply

Gradual Wear Diagnosis of Outer-Race Rolling Bearing Faults through Artificial Intelligence Methods and Stray Flux Signals

Electric motors have been widely used as fundamental elements for driving kinematic chains on mechatronic systems, which are very important components for the proper operation of several industrial applications. Although electric motors are very robust and efficient machines, they are prone to suffer from different faults. One of the most frequent causes of failure is due to a degradation on the bearings. This fault has commonly been diagnosed at advanced stages by means of vibration and current signals. Since low-amplitude fault-related signals are typically obtained, the diagnosis of faults at incipient stages turns out to be a challenging task. In this context, it is desired to develop non-invasive techniques able to diagnose bearing faults at early stages, enabling to achieve adequate maintenance actions. This paper presents a non-invasive gradual wear diagnosis method for bearing outer-race faults. The proposal relies on the application of a linear discriminant analysis (LDA) to statistical and Katz’s fractal dimension features obtained from stray flux signals, and then an automatic classification is performed by means of a feed-forward neural network (FFNN). The results obtained demonstrates the effectiveness of the proposed method, which is validated on a kinematic chain (composed by a 0.746 KW induction motor, a belt and pulleys transmission system and an alternator as a load) under several operation conditions: healthy condition, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm hole diameter on the bearing outer race, and 60 Hz, 50 Hz, 15 Hz and 5 Hz power supply frequencies

Electrical and Optical Characterization of Gliding Arc Discharge (GAD) Operated at Line Frequency (50 Hz) Power Supply

In this study, an atmospheric alternating-current gliding arc device using line frequency (50 Hz) has been designed for the generation of various reactive species in different working gases. Electrical characteristics of the generated discharge are investigated by oscilloscope while the optical characteristics are analyzed using optical emission spectroscopy. The role of different working gases (oxygen, argon and air) on discharge voltages and power consumption per cycle in the discharge are calculated and compared. Electron density and electron temperature of the discharge are estimated by electrical and optical method respectively. The production of reactive species in the discharge is affirmed by optical emission spectroscopy. The outcomes of the results confirm that the GAD can generate non-equilibrium plasma having reactive nitrogen and oxygen species (RONS) which are essential for plasma chemistry applications.

An Experimental Study of Co-Axial Dielectric Barrier Discharge for Ozone Generation

In this research work, co-axial cylindrical dielectric barrier discharge (CCDBD) system has been used as a ozone generator for ozone production with air as a working gas. The breakdown of air was generated inside the reactor by using low line frequency of 50 Hz and high AC voltage power supply system. The variation of air flow rate (Q) was taken from 10 to 16 l/min in this experiment. The O3 concentration denoted by C(O3) decreases with increasing the rate of flow of air at fixed discharge time and applied voltage. When discharge time (t) increases, C(O3) increases at fixed applied voltage. C(O3) also increases with increasing applied voltage (V) for constant discharge time. If the gap space between the electrodes increases then C(O3) increases. We have used glass tube reactor for this work having internal diameter of 18 mm and copper, brass and iron electrodes of diameter 8 mm. It was estimated that C(O3) found higher for copper electrode than both brass and iron electrode for certain discharge time, applied voltage and reactor diameter.

Indirect 3D-Space Vector Modulation for Matrix Converter

This paper discusses the indirect space vector modulation for four-leg matrix converter. Four-leg matrix converter has been proven to be a reliable, cost-effective, and compact power electronic interface to supply unbalanced or nonlinear loads. However, the added fourth leg has shifted the inverter side modulation from simple two-dimension SVM into complex three-dimension. This paper employs a new technique to implement indirect 3D SVM in digital controllers with further simplification in the modulation process. Moreover, Simulink simulation using repetitive controller has been performed to regulate the output voltage for 400 Hz Power supplies.

Super-low-frequency wireless power transfer with lightweight coils for passing through a stainless steel plate.

To achieve wireless power transfer (WPT) through a stainless-steel plate, a super-low frequency (SLF) was used as a resonance frequency. In our previous study of SLF-WPT, heavy coils were prepared. In this study, we designed lightweight coils using a WPT simulator that we developed previously. As a result, the weight was reduced to 1.69 kg from 11.9 kg, the previous coil weight. At a resonance frequency of 400 Hz, the transmission efficiency and output power of advanced SLF-WPT reached 91% and 426 W, respectively, over a transmission distance of 30 mm. Furthermore, 80% efficiency and 317 W output were achieved when transmitting power through a 1 mm-thick stainless-steel plate. This performance is much better than that in previous reports. We show using both calculations and experimental results that a power-to-weight ratio of 252 W/kg is possible even when using a 400 Hz power supply frequency.

Concept and testing of an electromagnetic homing guidance system for autonomous underwater vehicles

An effective homing guidance system with precise vehicle dynamic attitude control capability is essential for reliable docking of Autonomous Underwater Vehicles (AUV). The paper describes the bio-inspired concept and electromagnetic finite element analysis-aided design and testing of an electromagnetic homing guidance system (EMHGS) comprising of an underwater dock with 400AT of electromagnetic dipole coil excited with the 20 Hz power supply; a twin-thruster AUV equipped with a differential magnetometer system, and operable in two degrees of freedom (DOF). The vehicle hydrodynamic behavior is characterized in 2 DOFs based on the thruster action and vehicle response method, and used for the control and homing guidance of the AUV. By sensing a magnetic field strength of 190nT, the EMHGS is found to have an effective range of 7 m, and capable of effecting AUV orientation correction by measuring the bearing angle. The FEA is found to comply with the experimental observations with an accuracy of 96% is extended for higher dock magnetic field strengths, and found that an EMHGS utilizing 6000AT dock coil and magnetic field sensors of same sensitivity could have a homing guidance range of 72 m. Based on a priori magnetic map, the system is capable of computing the vehicle range and velocity, serving critical inputs for realizing effective AUV short range homing and docking.

Equalization Method of the Wireless Power Transfer in an Electronic Shelf Label Power Supply System

In a wireless power transmission device that drives multiple power outputs for electronic shelf labels (ESLs), we propose a novel rail transformer design for use with a 50/60 Hz power supply. By periodically short circuiting the receiving coils located closest to the transmitting coil, we experimentally verified that power can be transmitted to each ESL in a significantly uniform fashion. We expect the present approach with periodically switched receiver coils to be much more convenient, reliable, and flexible than our previous method of physically adjusting the air gaps between coils. In verification experiments, the output power of three receiving coils in a prototype was equalized at a level of approximately 60 mW. Without periodic switching, the output power of the center receiving coil only reached 40 mW, whereas, the receiving coils closest to the transmitting coils reached an output level of 80 mW, with output power fluctuating by approximately 49%. This paper demonstrates an effective design strategy for wireless power transfer devices.

Analysis of the Vacuum Arc Interruption Process in Aviation Intermediate-Frequency Power Supply Systems

In this paper, we present our research into the interruption performance of vacuum circuit breakers in aviation intermediate-frequency (360 Hz to 800 Hz) power supply systems. Intermediate-frequency vacuum arc experiments were carried out in interrupters with a diameter of 41 mm and CuCr50 alloy contact material. The results show that, as the frequency and peak value of the current increase, both the peak value and rise rate of the intermediate-frequency vacuum arc voltage also increase, and the interruption ability decreases. However, compared to the power frequency current at the same value, the erosion of the contacts is weaker over a shorter arc period. When the vacuum arc reignites, metal droplets are emitted from the contacts. The drive force is from the center of the contact to the edge. If the density of the plasmas and metal vapors and the number of the metal droplets reaches a certain level, the arc may break down, which will cause the interruption to fail.

Concentrated high intensity electric field (CHIEF) system for non-thermal pasteurization of liquid foods: Modeling and simulation of fluid mechanics, electric analysis, and heat transfer

Abstract This study develops an integrated, multi-scale model of the pilot concentrated high intensity electric field (CHIEF) system using the finite element method (FEM). The CHIEF system is a novel non-thermal pasteurization technology that uses medium to low voltage (≤10 kV) frequency AC (60 Hz) power supply, and offers satisfactory pasteurization results for liquid food such as juice and milk. The model in this study provides accurate predictions for the fluid behavior, electric field distribution and temperature profile and is validated using experimental results. Results from the model shows that the CHIEF system can provide electric field up to 4000 kV/m with a power supply of 10 kV, enabling a 6-log reduction of bacteria kill. Furthermore, recommendations and optimizations are made based on the modeling results, which would benefit for the process scale-up and design.

A 118 dB PSRR, 0.00067% (-103.5 dB) THD+N and 3.1 W Fully Differential Class-D Audio Amplifier With PWM Common Mode Control

This paper presents a fully differential Class-D audio amplifier using pulse-width modulation (PWM) common-mode control to enhance the power supply rejection ratio (PSRR) and linearity. The input feed-forward technique with resistive summation is adopted in the loop filter to reduce internal swing and signal-dependent terms for further linearity enhancement. Moreover, a single amplifier biaquad (SAB) technique is utilized to reduce the number of op-amps for low-power consideration. The Class-D audio amplifier achieves a high PSRR of 118 dB for 217 Hz power supply ripples and a low total harmonic distortion plus noise (THD+N) of 0.00067% (-103.5 dB). The proposed Class-D amplifier with 1.45 mA quiescent current shows a peak SNR (A-weighted) of 108 dB, the maximum output power of 3.1 W at 1% THD+N, and 89.5% efficiency with a $4~\Omega $ load. The Class-D audio amplifier, which occupies the active area of 1.85 mm2 in a $0.153~\mu $ m 1P5M CMOS process, can be operated from 3 V to 5.5 V.

A power supply error correction method for single-ended digital audio class D amplifiers

ABSTRACTIn single-ended digital audio class D amplifiers (CDAs), the errors caused by power supply noise in the power stages degrade the output performance seriously. In this article, a novel power supply error correction method is proposed. This method introduces the power supply noise of the power stage into the digital signal processing block and builds a power supply error corrector between the interpolation filter and the uniform-sampling pulse width modulation (UPWM) lineariser to pre-correct the power supply error in the single-ended digital audio CDA. The theoretical analysis and implementation of the method are also presented. To verify the effectiveness of the method, a two-channel single-ended digital audio CDA with different power supply error correction methods is designed, simulated, implemented and tested. The simulation and test results obtained show that the method can greatly reduce the error caused by the power supply noise with low hardware cost, and that the CDA with the proposed method can achieve a total harmonic distortion + noise (THD + N) of 0.058% for a –3 dBFS, 1 kHz input when a 55 V linear unregulated direct current (DC) power supply (with the –51 dBFS, 100 Hz power supply noise) is used in the power stages.

New harmonic mitigation scheme for modular multilevel converter – an experimental approach

The multilevel converter has been brought into limelight in this study; however, particular attention has been provided to the form and function of modular multilevel converter (MMC) with new controller to mitigate the circulating currents and harmonics present in the system. Till date, research in this field is very limited with circulating currents and harmonics as the major problem. The stability analysis of proposed controller has been derived and analysed with its experimental results. The system is examined before and after application of controller and results is analysed. This article effectively addresses the problem with prototype of 1 KVA implementation and attempts to make a detailed analysis with their functions in comprehensive manner with HVDC application under different conditions. Also, the applicability of zero voltage switching at turn on, zero current transition at turn off has been verified experimentally. Computer simulations and experiment on a 50 Hz power supply show that the new controller is effective and easy to implement for modular multilevel inverters.

Analysis of the flow rate characteristics of valveless piezoelectric pump with fractal-like Y-shape branching tubes

Microchannel heat sink with high heat transfer coefficients has been extensively investigated due to its wide application prospective in electronic cooling. However, this cooling system requires a separate pump to drive the fluid transfer, which is uneasy to minimize and reduces their reliability and applicability of the whole system. In order to avoid these problems, valveless piezoelectric pump with fractal-like Y-shape branching tubes is proposed. Fractal-like Y-shape branching tube used in microchannel heat sinks is exploited as no-moving-part valve of the valveless piezoelectric pump. In order to obtain flow characteristics of the pump, the relationship between tube structure and flow rate of the pump is studied. Specifically, the flow resistances of fractal-like Y-shape branching tubes and flow rate of the pump are analyzed by using fractal theory. Then, finite element software is employed to simulate the flow field of the tube, and the relationships between pressure drop and flow rate along merging and dividing flows are obtained. Finally, valveless piezoelectric pumps with fractal-like Y-shape branching tubes with different fractal dimensions of diameter distribution are fabricated, and flow rate experiment is conducted. The experimental results show that the flow rate of the pump increases with the rise of fractal dimension of the tube diameter. When fractal dimension is 3, the maximum flow rate of the valveless pump is 29.16 mL/min under 100 V peak to peak (13 Hz) power supply, which reveals the relationship between flow rate and fractal dimensions of tube diameter distribution. This paper investigates the flow characteristics of valveless piezoelectric pump with fractal-like Y-shape branching tubes, which provides certain references for valveless piezoelectric pump with fractal-like Y-shape branching tubes in application on electronic chip cooling.

Theory and experimental verification on valveless piezoelectric pump with multistage Y-shape treelike bifurcate tubes

Among most traditional piezo water cooling systems, piezoelectric valve pumps are adopted as their driving sources. The valves in these pumps induce problems of shock and vibration and also make their structure complicated, which is uneasy to minimize and reduce their reliability and applicability of the whole system. In order to avoid these problems caused by valve structure, a novel valveless piezoelectric pump is developed, which integrates both functions of transforming and cooling. The pump’s Y-shape tree-like construction not only increases the efficiency of cooling but also the system reliability and applicability. Firstly, a multistage Y-shape treelike bifurcate tube is proposed, then a valveless piezoelectric pump with multistage Y-shape treelike bifurcate tubes is designed and its working principle is analyzed. Then, the theoretical analysis of flow resistance characteristics and the flow rate of the valveless piezoelectric pump are performed. Meanwhile, commercial software CFX is employed to perform the numerical simulation for the pump. Finally, this valveless piezoelectric pump is fabricated, the relationship between the flow rates and driving frequency, as well as the relationship between the back pressure and the driving frequency are experimentally investigated. The experimental results show that the maximum flow rate is 35.6 mL/min under 100 V peak-to-peak voltage (10.3 Hz) power supply, and the maximum back pressure is 55 mm H2O under 100 V (9 Hz) power supply, which validates the feasibility of the valveless piezoelectric pump with multistage Y-shape treelike bifurcate tubes. The proposed research provides certain references for the design of valveless piezoelectric pump and improves the reliability of piezo water cooling systems.

Spatiotemporal study of the local thermodynamic equilibrium deviations in high-intensity discharge lamps

The aim of this work is to study the local thermodynamic equilibrium (LTE) deviations in arc discharges plasma generated in high-intensity discharge lamps operating under an ac (50 Hz) power supply. To achieve this goal, we elaborate a two-temperature, two-dimensional, and time-depending model. We have found numerical results almost reproducing the experimental data, which allows us to validate this model. After validation, we have discussed different energy term effects on the LTE deviations.