Analysis Of Current Waveforms Research Articles

Study on the design and fabrication of Silicon-Based integrated current sensor based on 3D Through-Silicon-Via (TSV) Rogowski coil

With the rapid advancement of microelectronics, 3D silicon-based integration microsystem technology has found widespread applications in various interconnected domains such as power generation, electric vehicles, smart grids, automation, and the Internet of Things (IoT). The high integration density within three-dimensional integrated microsystems has resulted in increasingly complex coupling between components, underscoring the critical importance of system health diagnostics. Presently, current waveform analysis, which yields valuable insights into the circuit system's condition, serves as a prevalent technique for system health assessment. However, traditional current sensors, typically packaged as discrete devices for current sensing, are inadequate for internal electrical signal detection within 3D IC microsystems. Therefore, this paper presents the design of a silicon-based integrated 3D Through-Silicon-Via (TSV) Rogowski coil tailored for in-situ electric current measurement. The structure and parasitic parameters of the 3D TSV Rogowski coil are meticulously determined through finite element method (FEM) simulations, facilitating the development of an appropriate signal processing circuit. Moreover, an Ordinary Differential Equation (ODE) current reconstruction method is proposed for measuring current. Leveraging this structural and circuit design, on-chip silicon-based integrated 3D TSV Rogowski coils are fabricated, followed by rigorous experimental validation. The experimental results convincingly attest to the effective in-situ current measurement capability of the on-chip silicon-based integrated 3D TSV Rogowski coil for 3D IC microsystems.

An improved online minor turn-turn winding fault diagnosis in a single-phase transformer based on instantaneous induced voltages and primary current locus

Online detection of the minor turn-turn winding fault in a single-phase transformer under no load condition using current waveform analysis is very complicated. In this paper, a new online minor turn-turn winding fault diagnosis in a single-phase transformer is proposed. Using a correlation between the instantaneous primary and secondary induced voltages difference with the primary current as a geometry location, the minor winding faults is detected effectively. The healthy transformer locus is considered as a reference locus. The minor winding faults could be detected by graphical analysis of the faulty loci with the reference locus in every cycle. Incipient winding fault detection in a single-phase transformer using the proposed technique under no load condition is a significant of this paper. The proposed locus is changed in shape and dimension by the winding faults severity. Therefore, the minor winding faults severity determination is carried out by faulty locus area comparison with the healthy locus. The experimental results validate the simulation results completely.

Numerical Overcurrent Power Relay Enhancement Based on Integrated Discrete Wavelet Transform

As electrical power demands increases, the need for advanced protection relays has surged as a vital element in the power distribution system. That is, to ensure the continuity of power supply and eliminate abnormal faulty status, relays with different types and functions play a major role in electrical power system operation and protection as will. In the power system, current variation faults may accrue for many reasons, which may harm power system components, load, and jeopardize human safety. However, in now a day digital current relay, a large number of samples are collected and processed in order to continuously monitor and detect faults. This large amount of samples needs a bigger storage data real state and longer time to compile, optimization is needed to improve current relay reliability and accuracy with much fewer samples. Therefore, as this work aim toward optimizing the current relay, a substantial algorithm is needed for better current waveform analysis. As a result, the Wavelet transform algorithm with its wide spectrum feature of waveform analysis and decomposition process will be used as an enhancement tool. Using MATLAB/Simulink, a simulation, the unique characteristics of Wavelet transform (de-noising, mining, and decomposition) will be implemented into the modern numerical current relay to test the ability to advance fault detection based on less number of current waveform data. As this evaluation was compared with a typical conventional numerical overcurrent relay, a promising result in terms of less response time and compiling process was achieved.

POWER QUALITY MONITORING FOR INDUSTRIAL LOAD

Power quality monitoring is critical in ensuring the efficient and reliable operation of industrial systems. This paper presents a MATLAB-based simulation approach for power quality monitoring, providing a cost-effective and scalable solution for industrial applications. The idea behind this paper is to design and simulate a comprehensive power quality monitoring system that includes voltage and current measurement, harmonic detection, waveform analysis, and microcontroller-based data processing. This simulation environment allows for the evaluation of various power quality parameters and the optimization of system parameters for accurate assessment. The abstracted system integrates sensor data acquisition, signal processing algorithms, and communication modules within the MATLAB framework. Through extensive simulations and parameter tuning, the system can effectively detect and mitigate power quality issues such as harmonics, voltage sags, swells, and transients. This paper significance lies in its ability to offer a robust, cost- effective, and customizable solution for power quality monitoring in industrial settings, ultimately ensuring the longevity and reliability of critical equipment and processes. The presentation will provide insights into the design, simulation, and potential real-world implementation of this MATLAB-based power quality monitoring system. Keywords –Harmonics, THD analysis, Fault correction, FFT analysis, Matlab simulation.

Sympathetic Transformer Inrush Detection and Relay Blocking During Power System Restoration

A classic inrush current occurs during normal energization of reactive grid elements like transformers. It can simulate short-circuit currents. Hence inrush currents have to be detected and protection relays need to be blocked for avoiding their overfunction. Conventional detection criteria are the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$2^{\textrm {nd}}$</tex-math></inline-formula> harmonic content and some kind of current waveform analysis. A classic inrush can evolve into a sympathetic inrush event, if the energization of a single transformers drives other transformers into magnetic saturation. The risk of facing a sympathetic inrush current is particularly high during a power system restoration process. Its characteristic waveform differs from the classic inrush. While the classic inrush has unipolar current peaks, the sympathetic inrush is characterized by bipolar peaks. The conventional detection criteria tend to fail in this case. This paper proposes a new approach to detect sympathetic transformer inrush currents. The approach includes the detection of classic inrush currents as well as the distinction against short-circuit currents for ensuring the relay blocking. First it introduces the basic physical mechanism behind the evolution of a classic to a sympathetic inrush. The higher risk of facing a sympathetic inrush during the restoration process is shown by the physical mechanism as well. The proposed detection method is then introduced in detail. Three new differentiation criteria will be applied and merged together to a final decision. The paper closes with practical lab tests of the new approach on simulated sympathetic and measured classic inrush currents. All lab tests showed good results and promise a practical implementation in the grid.

Lightning current analysis for tall tower strike using 3D FEM

In this study, the lightning current waveforms at the middle and bottom positions for 60 m tall tower strikes were observed using the three-dimensional finite element method (3D-FEM). When creating the model for lightning current waveform analysis at the middle and bottom positions of towers, base current speed and ground conductivity characteristics were taken into account. The model was developed using scattering boundary conditions to avoid wave reflections and limit computation time. We have considered ground conductivity of 5.98 e7 S/m, 0.1 S/m, and 0.01 S/m, respectively, in our model. Base current speeds were considered in our model to be equal to the velocity of light, half of the velocity of light, and one-third of the velocity of light, respectively. This investigation will aid in developing a lightning protection strategy and a better understanding of the properties of lightning.

A Seasonal–Trend-Decomposition-Based Voltage-Source-Inverter Open-Circuit Fault Diagnosis Method

This article considers power transistor open-circuit fault in a two-level voltage-source inverter and proposes a highly accurate, robust, and simple diagnosis method based on seasonal–trend decomposition. First, the three-phase current signal is decomposed into the trend, seasonal, and remainder components through the simplified seasonal–trend decomposition algorithm. Then, two characteristics “seasonal index” and “trend index” are defined. The theoretical values of the two characteristic quantities under different conditions are derived through simplified current waveform analysis and approximate integral calculation. Finally, the thresholds of characteristic quantities are set, and the diagnosis algorithm is designed. Experiments verify the effectiveness and the merits of the proposed method.

Non-Parametric Statistical Analysis of Current Waveforms through Power System Sensors.

The protection, control, and monitoring of the power grid is not possible without accurate measurement devices. As the percentage of renewable energy sources penetrating the existing grid infrastructure increases, so do uncertainties surrounding their effects on the everyday operation of the power system. Many of these devices are sources of high-frequency transients. These transients may be useful for identifying certain events or behaviors otherwise not seen in traditional analysis techniques. Therefore, the ability of sensors to accurately capture these phenomena is paramount. In this work, two commercial-grade power system distribution sensors are investigated in terms of their ability to replicate high-frequency phenomena by studying their responses to three events: a current inrush, a microgrid "close-in", and a fault on the terminals of a wind turbine. Kernel density estimation is used to derive the non-parametric probability density functions of these error distributions and their adequateness is quantified utilizing the commonly used root mean square error (RMSE) metric. It is demonstrated that both sensors exhibit characteristics in the high harmonic range that go against the assumption that measurement error is normally distributed.

An Applied Ambiguity Function Based on Dechirp for MIMO Radar Signal Analysis

The orthogonal waveform design and good hardware realization of multiple-input–multiple-output (MIMO) radar have always been important research topics. The orthogonal frequency division multiplexing (OFDM) chirp waveform has received more attention because of its large time-bandwidth product, constant modulus, no range-Doppler coupling, good orthogonality, and good Doppler tolerance. Dechirp technique can reduce the amount of raw sampled data very well in near-field miniature lightweight MIMO radar detection and synthetic aperture radar (SAR) imaging. However, most of the current waveform analysis methods are based on matched filtering (MF). In this letter, an ambiguity function (AF) based on the dechirp signal processing approach to analyze the waveform performance is proposed, called dechirp ambiguity function (DAF). The pulse compression performance of the waveform itself and the level of mutual interference between the waveforms are described from the perspective of DAF. Numerical results validate reliability and effectiveness of the DAF.

ВЛИЯНИЕ ИНДУКТИВНОСТИ НА ПАРАМЕТРЫ ПЛАЗМЕННОГО ФОКУСА В ИМПУЛЬСНОМ КОАКСИАЛЬНОМ УСКОРИТЕЛЕ

Based on the physical analysis of the processes occurring in pulsed plasma accelerators, the pos­sibility of their use for the creation and study of a plasma focus is justified. In particular, the influence of inductance on the parameters of the plasma focus in kilojoule­range «Plasma focus» (PF) installations created on the basis of a pulsed coaxial accelerator is studied. An equivalent installation scheme is proposed and justified, based on the analysis of which the influence of the inductance of the circuit and the capacitance of the capacitor bank on the value of the maximum current and neutron output is analyzed, without taking into account the parameters of the spark gap and the conducting wires. Based on the theoretical estimate of the inductance of the installation, its most probable value is calculated. . It turned out that in the installations of the considered energy range, the inductance is approximately 7.5•10­7 Gn and depends on the capacitance of the capacitor bank. On the contrary, in installations with megajoule energy, the inductance does not depend on the number and capacity of capacitors, so that an increase in the latter does not affect the increase in current strength. Experimental and theoretical dependences of the discharge current on the applied voltage at different capacitances of the capacitor bank are obtained. A comparative analysis of theoretical and experimental current waveforms is pre­sented. The greatest coincidence of theoretical and experimental results was found for the duration of the discharge pulse T = 30 microseconds.

Level Crossing Barrier Machine Faults and Anomaly Detection with the Use of Motor Current Waveform Analysis

Barrier machines are a key component of automatic level crossing systems ensuring safety on railroad crossings. Their failure results not only in delayed railway transportation, but also puts human life at risk. To prevent faults in this critical safety element of automatic level crossing systems, it is recommended that fault and anomaly detection algorithms be implemented. Both algorithms are important in terms of safety (information on whether a barrier boom has been lifted/lowered as required) and predictive maintenance (information about the condition of the mechanical components). Here, the authors propose fault models for barrier machine fault and anomaly detection procedures based on current waveform observation. Several algorithms were applied and then assessed such as self-organising maps (SOM), autoencoder artificial neural network, local outlier factor (LOF) and isolation forest. The advantage of the proposed solution is there is no change of hardware, which is already homologated, and the use of the existing sensors (in a current measurement module). The methods under evaluation demonstrated acceptable rates of detection accuracy of the simulated faults, thereby enabling a practical application at the test stage.

In and Al Schottky Contacts Comparison on P-Type Chlorine-Doped CdTe.

The performance of the CdTe radiation detectors heavily relies on the method of contact preparation. A convenient research method addressing this problem is the laser-induced transient current technique. In this paper, we compare the performance of two CdTe crystals which underwent different metallization processes. We showed that appropriately designed Au/Al contacts induce much less bulk polarization than commercial Pt/In electrodes under the same working conditions and can thus provide a convenient alternative to the industry standard. The comparison was based on the monitoring of the time-dependent sensor polarization measuring transient currents excited by above-bandgap laser illumination complemented by the Am 241 gamma spectroscopy. The theoretical analysis of current waveforms and radiation spectra enabled us to determine the charge carrier mobility, mobility-lifetime products of electrons and holes, and temporal and bias dependence of the space charge formation.

Fault Loop Impedance Measurement in Circuits Fed by UPS and Principle of Safety Protection

This paper indicates a significant problem of uncertainty of fault loop impedance (FLI) measurement in circuits powered from uninterruptible power supply (UPS) (double-conversion AC-DC-AC). The correctly determined value of this impedance, related to the short-circuit current disconnection time and to the reference value, is one of the most important elements that determines the approval of an electrical installation and its receivers for operation. To define the principles of FLI measurement, several hundred measurements of the short-circuit loop impedance in the circuits fed by the UPS, in various UPS operation modes and with various FLI instruments, were made, which allowed for the definition of measurement rules that reduce the error in assessing the effectiveness of protection against electric shock by automatic disconnection of supply. Based on the analysis of voltage and current waveforms recorded during the real short-circuit tests in the circuit fed by the UPS, a proprietary algorithm for determining the short-circuit loop impedance has been proposed.

Analysis of DC Motor Current Waveforms Affecting the Accuracy of “Sensorless” Angle Measurement

A typical approach for “sensorless” angle or speed measurement of dc machines is to evaluate periodic oscillations in the electrical motor signals which is also known as ripple counting. This method is usually applied to the current signal and very susceptible to counting errors due to different waveforms caused by various influences. In this article, the steady-state current waveforms of a small dc machine are investigated to identify the causes leading to incorrect counting results. The focus is on production tolerances and changes over the service life of the motor. This is done both by the experimental and simulative investigations and analysis of the signals in the time and frequency domains. For the simulative investigation, much attention is paid to suitable modeling for this particular task and parameter variations are performed to separate the influences on the current signal. The goal is a better understanding of the different waveforms and their causes as a basis for the development of future error-free counting algorithms.

A Bidirectional Three-Phase Push–Pull Converter With Hybrid PPS-DAPWM Switching Method for High Power and Wide Voltage Range Applications

High-power isolated bidirectional dc-dc converters with wide voltage range are attracting increasing attention in many applications. The bidirectional three-phase current-fed dc-dc converters are known to be suitable for wide voltage range applications compared to dual active bridge based converters, having advantages of reduced device current ratings and prevention of transformer saturation due to high impedance nature. However, when the duty cycle becomes lower than 0.33 or higher than 0.66, power transfer capability is limited, and the efficiency is significantly reduced due to increased circulating current, which has rarely been discussed so far. In this article, a hybrid dual-asymmetrical pulsewidth modulation (DAPWM) and pulsewidth modulation plus phase-shift (PPS) switching method is proposed for efficiency improvement of the bidirectional three-phase push-pull converter with very wide voltage range. A seamless mode change method between PPS and DAPWM is also proposed for minimizing the transient state. Further, through current waveform and power flow analysis, the leakage inductance along with transformer turn ratio are designed to minimize the root mean square (rms) current of devices, while having the capability of transferring the desired power and limiting the slew rate of transformer winding current under wide voltage range operation. Experimental results from a 22-kW prototype are provided to validate the proposed concept.

Generation and Diagnostics of Ambient Air Glow Discharge in Centimeter-Order Gaps

Re-pulsing glow discharges in gaps up to 2 cm were experimentally investigated in atmospheric pressure air. Discharge was ignited as a sequence of spark and glow discharge and sustained in a glow regime after ignition. It was confirmed that the discharge with defined parameters could be ignited without any adjustments after initiation of the discharge. The discharges were characterized by a high-speed camera, current and voltage measurements, and optical emission spectrometry (OES). Typical structure of the glow discharge consisting of cathode glow, dark faraday space, positive column, and anode glow was observed. Transition from subnormal to normal glow mode was confirmed by analysis of current and voltage waveforms. It was found by OES that the type of discharge strongly affects the ratio of produced reactive species. It was confirmed that with change of discharge from subnormal to normal glow regime, rotational temperature could vary across a wide range (from 1650 to 3500 K). The developed device allows glow discharge to be ignited with defined parameters, which makes the control of the gas temperature and ratio of reactive species possible by presetting the discharge parameters. Additionally, it was demonstrated that corona discharge or repeating spark discharges could also be generated using the developed device without additional manipulations of the experimental setup by adjusting the discharge parameters.

Magnetic-assisted method and multi-objective optimization for improving the machining characteristics of WEDM in trim cutting magnetic material

In wire electrical discharge machining (WEDM), increasing the machining characteristics is always a research hot spot. Now, magnetic-assisted method cannot directly improve the performance of WEDM during machining magnetic material. In addition, due to the defects of convergence precision, convergence speed, global optimization, and subjectivity, the application of individual parameter optimization algorithm is limited. In order to address these problems, this paper proposes magnetic-assisted method and modified non-dominated neighbor immune algorithm to ameliorate the performance of WEDM in trim cutting magnetic material. Firstly, the force analysis of debris and the analysis of discharge current waveform are carried out to clarify what setting condition of the magnetic field generator is proper. It is indicated that the magnetic-assisted method maybe improves the machining characteristics of WEDM when the Lorentz force has the same direction with dielectric flashing force during trim cutting magnetic material. Additionally, a set of trim cutting Taguchi experiment is accomplished to investigate the effect of magnetic-assisted method on material remove rate (MRR), surface roughness (SR), and recast layer thickness (RLT). Thereinto, it can be found that the machining characteristics of WEDM are obviously improved by magnetic-assisted method. More specifically, under magnetic-assisted method, MRR, SR, and RLT are improved by an average of 18.45, 17.86, and 17%, respectively. Then, on the basis of game theory, the modified non-dominated neighbor immune algorithm (NNIA) is proposed to select best process parameters for further increasing the machining characteristics of magnetic-assisted WEDM (MA-WEDM). Eventually, the comparative results of three algorithms and verification experiment demonstrate that this modified NNIA exhibits better optimization performance than NSGA-II and NNIA. Specifically, by modified NNIA, the largest increase of MRR and the greatest decrease of SR and RLT are 22.37, 44.59, and 15.07%, respectively.

Anode position influence on discharge modes of a LaB6 cathode in diode configuration

A laboratory model of a 5 A-class cathode was experimentally studied in diode configuration with a disk anode. The core of the cathode is a flat disk lanthanum hexaboride (LaB6) insert. Electron emission is achieved using a heating element in direct contact with the insert. The paper reports the characterization of the LaB6 cathode operated at xenon mass flow rates between 0.4 and 1.0 mg s−1 with discharge currents ranging from 2 A to 12 A. Apart from the operating envelope and discharge mode (spot versus plume) differentiation, the influence of anode position on cathode discharge mode was studied. For this purpose, the cathode was operated at 4 A and 0.6 mg s−1 and at 10 A and 0.6 mg s−1, while the cathode-anode gap was increased from 20 mm to 70 mm. Both electrical and plasma parameters were collected and analyzed in order to highlight the main changes in cathode discharge when the cathode-anode gap was increased. Particular attention was paid to the identification of the discharge mode and mode transition based on spectral analysis of discharge current waveforms. It was demonstrated that an increase in the cathode-anode gap induces the discharge mode transition from spot mode, corresponding to lower gap values, to plume mode, corresponding to higher gap values. Changes in plasma property were also noticed, the cathode-anode gap increase inducing lower plasma density and higher electron temperature in the cathode plume.

Gap bridging of 6061 aluminum alloy joints welded by variable-polarity cold metal transfer

6061 aluminum alloy joints at different gap widths were welded successfully with the same parameters (except wire offset). Bead formation, microhardness, shear strength, fracture characteristic, and forming mechanism were investigated. The results indicated that the shear strength of the joints decreased with increasing gap width. The gap width had little impact on the hardness of joints, and the fracture mode of the samples at different gap widths was ductile fracture. The wire offset and wire feeding speed had significant effects on the bead formation. The results of high-speed video and current waveform analysis showed that the variable-polarity cold metal transfer (CMT) Advance (C + A) process had better gap-bridging ability due to a lower heat input and higher deposition rate compared with the conventional CMT mode.

Module’s overheating assessment with the use of supply current waveform analysis

Design and manufacturing of electronic modules is a difficult process - on the one hand there arises a problem of developing the inner circuitry of best possible performance, on the other hand -building it at the lowest possible price. When it comes to cutting expenses on production, even the smallest changes in materials can critically influence the total manufacturing costs. The paper introduces a method of detecting certain module’s overheating levels without a necessity of using temperature sensors - devices generating unnecessary fabrication expenses. The assessment of temperature can be performed with the use of supply current waveform analysis - particular changes in current function caused by overheating may be processed and correlated with a certain temperature. Finding those differences in supply waveforms and classifying them may be done with either analytic methods or heuristic algorithms.