Current Measurements Research Articles

Simulation of Strain in ReBCO Tapes Under Combined Helical-Hard-Way Bending and Critical Current Measurements

Simulation of Strain in ReBCO Tapes Under Combined Helical-Hard-Way Bending and Critical Current Measurements

Critical Current Measurements of Prototype REBCO Round Cables at 77 K

Critical Current Measurements of Prototype REBCO Round Cables at 77 K

Displacement damage effect of proton irradiation on vertical β-Ga2O3 and SiC Schottky barrier diodes (SBDs)

In this study, we fabricated vertical Schottky barrier diodes (SBDs) based on wide bandgap semiconductor beta-phase gallium oxide (β-Ga2O3) and silicon carbide (SiC), respectively, and conducted proton irradiation experiments to analyze the radiation hardness of the SBDs comparatively. The effects of proton radiation on the performance of SBDs were assessed through measurements of forward current, capacitance, and breakdown characteristics. Both devices exhibited degradation in current and capacitance characteristics following proton irradiation, attributed to displacement damage (DD). Notably, the β-Ga2O3-based SBD demonstrated more pronounced deterioration compared to the SiC-based device despite similar vacancy distributions as confirmed by SRIM simulation. Moreover, a decrease in contact radius correlated with exacerbated degradation in the current characteristics of the β-Ga2O3-based SBD. Following proton irradiation, breakdown voltages of both devices increased due to elevated resistance induced by displacement damage. While both β-Ga2O3 and SiC-based SBDs experienced displacement damage under high fluence proton irradiation, the extent of performance degradation varied depending on the dimensions and quality of epitaxial and substrate layers.

Fast Calibration With Raw Data Verification for Current Measurement of Dual-PMSM Drives

Fast Calibration With Raw Data Verification for Current Measurement of Dual-PMSM Drives

Primary-Side Indirect Control of the Battery Charging Current in a Wireless Power Transfer Charger Using Adaptive Hill-Climbing Control Technique

This paper addresses the control task of a wireless power transfer (WPT) charger designed for electric vehicles (EVs). The challenge is to maintain a constant battery charging current when the WPT is controlled on the ground side. Indeed, the intermittent latency involved in the wireless data communication between the ground and vehicle sides leads to system instability. To overcome this issue, a new control approach has been proposed in this paper. The proposed technique ensures indirect control of the battery charging current through control of the current on the ground side. The control technique relies on an adaptive hill-climbing algorithm in conjunction with a PI-based controller. The adaptive parameter is adjusted online, during the operation of the charger, only when a new measure of the battery charging current is received on the primary side. This makes it possible to avoid the need for real-time wireless data communication. It should be noted that this aspect is crucial in ensuring the controller’s robustness and stability of the system regardless of potential delays in wireless communication and large misalignments between the coils. The validity of the proposed control technique has been confirmed through simulation. In addition, experimental validation, using a laboratory test bed, demonstrated satisfactory results.

Research on the application of fiber-optical current sensor in power battery

Abstract Compared with the total current, the current in each parallel branch will help to achieve better battery management for new energy vehicles. However, today, accurate measurement of branch current is very difficult because the space between branches in the power battery pack is very limited. In this study, the fiber-optic current mini-sensor is used to meet this challenge. A saddle-sensing fiber structure has been designed to achieve surface measurement in response to the specific interconnection of circuitry in battery packs. A computer simulation was used to validate the feasibility, and experimental testing showed positive results. The specific experiments confirmed that the relative error between the saddle fiber-optic current sensor and conventional fiber-optic loop current sensor does not exceed 0.0119%. It meets the requirements of the automotive industry standards.

C-Shape Busbar With Frequency Invariant Points for Wideband Current Measurement

C-Shape Busbar With Frequency Invariant Points for Wideband Current Measurement

Fat quantification in dual-layer detector spectral CT: How to handle iron overload, varying tube voltage and radiation dose Indices.

Opposed to other spectral CT techniques, fat quantification in dual-layer detector CT (dlCT) has only recently been developed. The impact of concomitant iron overload and dlCT-specific protocol settings such as the dose right index (DRI), a measure of image noise and tube current, on dlCT fat quantification was unclear. Further, spectral information became newly available <120 kV. Therefore, this study's objective was to evaluate the impact of iron, changing tube voltage, and DRI on dlCT fat quantification. Phantoms with 0 and 8mg/cm3 iron; 0 and 5mg/cm3 iodine; 0, 10, 20, 35, 50, and 100% fat and liver equivalent, respectively, were scanned with a dlCT (CT7500, Philips, the Netherlands) at 100kV/20DRI, 120kV/20DRI, 140kV/20DRI, and at 120kV/16DRI, 120kV/24DRI. Material decomposition was done for fat, liver, and iodine (A1); for fat, liver, and iron (A2); and for fat, liver, and combined reference values of iodine and iron (A3). All scans were analyzed with reference values from 120kV/20DRI. For statistics, the intraclass correlation coefficient (ICC) and Bland-Altman analyses were used. In phantoms with iron and iodine, results were best for A3 with a mean deviation to phantom fat of 1.3±2.6% (ICC 0.999 [95%-confidence interval 0.996-1]). The standard approach A1 yielded a deviation of -2.5±3.0% (0.998[0.994-0.999]), A2 of 6.1±4.8% (0.991[0.974-0.997]). With A3 and changing tube voltage, the maximal difference between quantified fat and the phantom ground truth occurred at 100kV with 4.6±2.1%. Differences between scans were largest between 100kV and 140kV (2.0%[-7.1-11.2]). The maximal difference of changing DRI occurred between 16 and 24 DRI with 0.4%[-2.2-3.0]. For dlCT fat quantification in the presence of iron, material decomposition with combined reference values for iodine and iron delivers the most accurate results. Tube voltage-specific calibration of reference values is advisable while the impact of the DRI on dlCT fat quantification is neglectable.

SnS2 memtransistor-based Lorenz chaotic system for true random number generation

As the Internet of Things (IoT) landscape expands, the need for robust and energy-efficient hardware security has increased. In this study, we demonstrate a novel true random number generation (TRNG) system that combines a tin disulfide (SnS2) nanosheet-based memtransistor with the Lorenz chaotic system. This synergy leverages the intrinsic stochasticity of electron trapping at the SnS2 interfaces and the energy efficiency of the Lorenz chaotic system realized by an analog circuit. In addition, we provide a comprehensive evaluation of the energy consumption of the entire TRNG system based on direct measurements of the supply current. Remarkably, our TRNG achieves an energy consumption of 4.3 μJ/bit with a throughput of 10 kbit/s.

Sensorless Model Predictive Control of Permanent Magnet Synchronous Motors Using an Unscented Kalman Filter

This paper deals with the application of the Model Predictive Control (MPC) algorithm to the sensorless control of a Permanent Magnet Synchronous Motor (PMSM). The proposed estimation strategy, based on the unscented Kalman filter (UKF), uses only the measurement of the motor current for the online estimation of speed, rotor position and load torque. Information about the system state is fed into the MPC algorithm. The results verify the effectiveness and applicability of the proposed sensorless control technique. To demonstrate its real-world applicability, implementation in low-speed direct drive astronomy telescope mount systems is investigated. The outcomes of the implementation are thoroughly examined, leading to insightful conclusions drawn from the observed results. Through rigorous theoretical analysis and extensive simulation studies, this paper establishes a solid foundation for the proposed sensorless control technique. The results obtained from simulation studies and real-world applications underscore the efficacy and versatility of the proposed approach, offering valuable insights for the advancement of sensorless control strategies in motor applications. The main aim of this work is to demonstrate and validate the practical feasibility of combining two complex techniques, establishing that such an integration is not only possible but also effective in achieving the desired objectives.

Improved Common-Mode Leakage Current Measurement Method for Insulation Condition Monitoring in Distribution Grids

Common-mode (CM) leakage current is an essential insulation indicator for condition monitoring in distribution grids. However, online measurement of CM leakage current is a difficult task in the industry due to the disturbances of far larger load currents. To address this challenge, a novel CM leakage current measurement method based on multi-layer magnetic shield has been proposed in this paper. The analytical solution for the magnetic field around the shield is firstly derived and validated by finite element analysis. Comprehensive comparison with previous single-layer shield design is then conducted for a typical industrial case, proving that an improvement of about 46 dB can be achieved for CM leakage current measurement by the novel design. A sensor prototype has also been developed with optimized parameters and validated by experiments. The effectiveness of the proposed method is proved, with minor CM leakage current accurately extracted from load currents which are 3000 times larger.

Similarity measure between generalized intuitionistic fuzzy sets with three kinds of negation

The similarity measure of intuitionistic fuzzy sets is a primary method for dealing with uncertainty and fuzzy problems and is commonly used in fuzzy decision-making and pattern recognition. The current mainstream similarity measure is based on the classical fuzzy set with only one negation, which often violates the intuitionistic problem in applications because the actual semantics of multiple negations are not considered. To solve the inconsistency and irrationality problems in the classical similarity methods, we introduce three negations (contradiction negation, opposition negation, and mediation negation) in the intuitionistic fuzzy set to obtain the generalized intuitionistic fuzzy set and prove its related property theorem. On this basis, our similarity measure adopts a mediational negation to represent non-membership, which fully utilizes the multiple negation information of non-membership and hesitancy and avoids the loss of fuzzy information. We verify the method’s rationality, validity, and originality through pattern recognition experiments and numerical examples, which improves the performance of intuitionistic fuzzy set similarity in practical applications and provides a new approach for future research on intuitionistic fuzzy inference.

Mapping the Viewer Experience in Cinematic Virtual Reality: A Systematic Review

Abstract In recent years, the creative media landscape has witnessed growing interests surrounding the utilization of virtual reality (VR) as a novel visual narrative approach for both filmmakers and audiences. This trend is accompanied by an increase in studies aimed at scientifically examining the characteristics and principles of immersive visual storytelling. This paper intends to contribute to this growing field by offering a comprehensive review on the current research development in cinematic virtual reality (CVR), which employs VR technology to produce immersive, cinematic experiences for audiences. While extant research has focused on the content generation techniques and human performance implicated in virtual environments, such investigations may not fully explain the medium adaptation differences or emotional dimensions of narrated immersive experiences. These aspects are especially crucial in the context of visual storytelling through VR film, 360-degree video production, or other narrated experiences. The proposed study systematically categorizes CVR-related research, revealing the field's current state by narrowing the focus to specific topics and themes within CVR literature and highlighting key subdomains of interest centered on viewers’ experience measurement techniques. The findings of this review are expected to establish formal categories for implementing visual CVR to achieve immersive visual storytelling and provide a comprehensive analysis of current viewer experience measurements.

Current Measurement Gain Compensation Using High-Frequency Signal Injection in Dual Three-Phase PMSM Systems

To online compensate the scaling errors in current measurement caused by incorrect calibration, temperature, aging, and noise, this paper proposes a new solution based on high-frequency (HF) carrier voltage injection in dual three phase permanent magnet synchronous machines. The relationship between the measured HF currents and scaling errors is derived. It shows that the amplitudes of the HF currents are proportional to the scaling errors, based on which three HF current control loops are subsequently designed to eliminate the measured HF currents and compensate the scaling errors. The designed HF controller are independent from the main current and torque regulators, and thus, it can be used for initial scaling gain calibration or periodically used during normal machine operation. Different from general three phase machine systems, the generated HF current components only exist in z <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> z <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> subspace, and thus, no extra torque ripples will be produced. Experimental results validate the proposed control algorithm.

A Novel Current Measurement Offset Error Compensation Method Based on the Adaptive Extended State Observer for IPMSM Drives

Offset error from the measured phase current mostly causes a performance afflicted for interior permanent-magnet synchronous motor (IPMSM) drives, and innovative solutions are eagerly sought. Considering this, this paper proposes an adaptive extended state observer (AESO) to compensate the current measurement offset error (CMOE) without additional hardware. In the proposed scheme, the AESO is designed in a stationary coordinate system to estimate CMOE in DC form. Notably, the proposed AESO possesses a second-order low-pass filtering characteristics. With this, the proposed method shows a high robustness against the disturbances from the AC components caused by motor parameter changes, etc. Furthermore, the adaptive gains enable the proposed scheme to maintain a satisfactory performance under the motor frequency changes. The feasibility of the proposed scheme is thoroughly verified by extensive experimental tests based on the test bench of a 3-kW IPMSM drives.

The value of multiplex PCR in describing the microbial ecology of respiratory infections during the COVID 19 pandemic

Respiratory infections constitute a frequent reason for consultation and hospitalization and their emergence means that the identification of pathogens is important for the implementation of appropriate treatment for effective patient care. Multiplex PCR is a diagnostic tool developed for the identification of the microbial agent and the detection of resistance mechanisms. The objective of this study was to highlight and identify by multiplex PCR the bacteria and viruses responsible for respiratory infections in patients presenting clinical signs, and in whom biological examinations did not identify germs in cause during the COVID 19 pandemic, to be able to follow the epidemiology and microbial ecology of lower respiratory infections which has undergone changes, due to hygiene rules as well as current measures and methods of controlling this pandemic.

Cybersecurity risks in online banking: A detailed review and preventive strategies applicatio

In an era where the digital transformation of the banking sector intersects with the escalating complexity of cyber threats, this paper endeavors to dissect the multifaceted realm of cybersecurity within the banking industry. With a backdrop of increasing online banking adoption and the concomitant rise in cybercrime, the study aims to illuminate the current cybersecurity landscape, evaluate the efficacy of existing frameworks and propose strategic enhancements to fortify digital defenses. Employing a methodological amalgam of literature review and analysis of recent cybersecurity incidents, this investigation delves into the intricacies of cyber threats, the financial repercussions of breaches and the robustness of current cybersecurity measures in banking. The scope of this paper encompasses a comprehensive examination of recent cyber incidents, an assessment of the financial impact of cyber-attacks, an evaluation of the effectiveness of existing cybersecurity frameworks and the formulation of strategic recommendations for bolstering cybersecurity measures. Through this scholarly inquiry, key findings emerge, highlighting the critical need for dynamic cybersecurity strategies that integrate advanced technologies, promote regulatory compliance and foster a culture of cybersecurity awareness. Conclusively, the study posits that the banking sector must embrace a holistic and adaptive approach to cybersecurity, underscored by strategic investments in technology, education, and collaboration. Recommendations advocate for the integration of Big Data analytics, artificial intelligence and continuous risk assessment methodologies to navigate the evolving cyber threat landscape effectively. This paper serves as a clarion call to banking institutions, urging a reinvigorated commitment to cybersecurity resilience in safeguarding financial assets and customer trust against the backdrop of digital transformation.

Development of a Follow-Up Measure to Ensure Complete Screening for Colorectal Cancer

The current quality performance measure for colorectal cancer (CRC) screening is limited to initial screening. Despite low rates, there is no measure for appropriate follow-up with colonoscopy after receipt of an abnormal result of a stool-based screening test (SBT) for CRC. A quality performance measure is needed. To develop and test a quality performance measure for follow-up colonoscopy within 6 months of an abnormal result of an SBT for CRC. This retrospective quality improvement study examined data from January 1, 2016, to December 31, 2020, with 2018 plus 6 months of follow-up as the primary measurement period to verify performance rates, specify a potential measure, and test for validity, reliability, and feasibility. The Optum Labs Data Warehouse (OLDW), a deidentified database of health care claims and clinical data, was accessed. The OLDW contains longitudinal health information on enrollees and patients, representing a diverse mixture of ages and geographic regions across the US. For the database study, adults from 38 health care organizations (HCOs) aged 50 to 75 years who completed an initial CRC SBT with an abnormal result were observed to determine follow-up colonoscopy rates within 6 months. Rates were stratified by race, ethnicity, sex, insurance, and test modality. Three HCOs participated in the feasibility field testing. Data were analyzed from June 1, 2022, to May 31, 2023. The primary outcome consisted of follow-up colonoscopy rates following an abnormal SBT result for CRC. Reliability statistics were also calculated across HCOs, race, ethnicity, and measurement year. Among 20 581 adults (48.6% men and 51.4% women; 307 [1.5%] Asian, 492 [7.2%] Black, 644 [3.1%] Hispanic, and 17 705 [86.0%] White; mean [SD] age, 63.6 [7.1] years) in 38 health systems, 47.9% had a follow-up colonoscopy following an abnormal SBT result for CRC within 6 months. There was significant variation between HCOs. Notably, significantly fewer Black patients (37.1% [95% CI, 34.6%-39.5%]) and patients with Medicare (49.2% [95% CI, 47.7%-50.6%]) or Medicaid (39.2% [95% CI, 36.3%-42.1%]) insurance received a follow-up colonoscopy. A quality performance measure that tracks rates of follow-up within 6 months of an abnormal SBT result was observed to be feasible, valid, and reliable, with a median reliability statistic between HCOs of 94.5% (range, 74.3%-99.7%). The findings of this observational study of 20 581 adults suggest that a measure of follow-up colonoscopy within defined periods after an abnormal result of an SBT test for CRC is warranted based on low current performance rates and would be feasible to collect by health systems and produce valid, reliable results.

Multi-Stimuli Operando Transmission Electron Microscopy for Two-Terminal Oxide-Based Devices.

The integration of microelectromechanical systems (MEMS)-based chips for in situ transmission electron microscopy (TEM) has emerged as a highly promising technique in the study of nanoelectronic devices within their operational parameters. This innovative approach facilitates the comprehensive exploration of electrical properties resulting from the simultaneous exposure of these devices to a diverse range of stimuli. However, the control of each individual stimulus within the confined environment of an electron microscope is challenging. In this study, we present novel findings on the effect of a multi-stimuli application on the electrical performance of TEM lamella devices. To approximate the leakage current measurements of macroscale electronic devices in TEM lamellae, we have developed a postfocused ion beam (FIB) healing technique. This technique combines dedicated MEMS-based chips and in situ TEM gas cells, enabling biasing experiments under environmental conditions. Notably, our observations reveal a reoxidation process that leads to a decrease in leakage current for SrTiO3-based memristors and BaSrTiO3-based tunable capacitor devices following ion and electron bombardment in oxygen-rich environments. These findings represent a significant step toward the realization of multi-stimuli TEM experiments on metal-insulator-metal devices, offering the potential for further exploration and a deeper understanding of their intricate behavior.

Disturbance observer-based fixed time control for bidirectional DC-DC converter with input voltage and load uncertainty

The bidirectional DC-DC converter serves a vital role in the energy recovery system of new energy vehicles. However, external interference and parameter uncertainty can easily affect its dynamic performance. A disturbance observer-based fixed time control strategy for bidirectional DC-DC is proposed to address the impact of input voltage and load uncertainty on bidirectional converters. Firstly, the bidirectional converter model undergoes coordinate transformation, and disturbance observers are designed to compensate for input voltage and load disturbances. Secondly, based on the fixed time control theory, a fixed-time controller is devised for the bidirectional DC-DC converter to facilitate fast tracking and adjustment of output voltage without requiring measurement of input voltage and load current. Finally, simulation and experiment evaluations are conducted to assess the proposed scheme’s effectiveness in output voltage regulation.