Current Sensor Research Articles

The 2019 Raikoke eruption as a testbed used by the Volcano Response group for rapid assessment of volcanic atmospheric impacts

Abstract. ​​​​​​​The 21 June 2019 Raikoke eruption (48° N, 153° E) generated one of the largest amounts of sulfur emission to the stratosphere since the 1991 Mt. Pinatubo eruption. Satellite measurements indicate a consensus best estimate of 1.5 Tg for the sulfur dioxide (SO2) injected at an altitude of around 14–15 km. The peak Northern Hemisphere (NH) mean 525 nm stratospheric aerosol optical depth (SAOD) increased to 0.025, a factor of 3 higher than background levels. The Volcano Response (VolRes) initiative provided a platform for the community to share information about this eruption which significantly enhanced coordination efforts in the days after the eruption. A multi-platform satellite observation subgroup formed to prepare an initial report to present eruption parameters including SO2 emissions and their vertical distribution for the modeling community. It allowed us to make the first estimate of what would be the peak in SAOD 1 week after the eruption using a simple volcanic aerosol model. In this retrospective analysis, we show that revised volcanic SO2 injection profiles yield a higher peak injection of the SO2 mass. This highlights difficulties in accurately representing the vertical distribution for moderate SO2 explosive eruptions in the lowermost stratosphere due to limited vertical sensitivity of the current satellite sensors (±2 km accuracy) and low horizontal resolution of lidar observations. We also show that the SO2 lifetime initially assumed in the simple aerosol model was overestimated by 66 %, pointing to challenges for simple models to capture how the life cycle of volcanic gases and aerosols depends on the SO2 injection magnitude, latitude, and height. Using a revised injection profile, modeling results indicate a peak NH monthly mean SAOD at 525 nm of 0.024, in excellent agreement with observations, associated with a global monthly mean radiative forcing of −0.17 W m−2 resulting in an annual global mean surface temperature anomaly of −0.028 K. Given the relatively small magnitude of the forcing, it is unlikely that the surface response can be dissociated from surface temperature variability.

All-Textile Piezoelectric Nanogenerator Based on 3D Knitted Fabric Electrode for Wearable Applications.

Flexible, air permeable and elastic self-powered sensors for human motion monitoring and assisted medical rehabilitation have recently become a hot research topic. However, most current piezoelectric sensors can not account for many characteristics. Addressing this challenge, an all-textile piezoelectric sensor (ATPS) based on 3D structured knitted fabric electrodes is reported. The ATPS consists of a piezoelectric element polyvinylidene fluoride nanofiber membrane, flexible knitted fabric electrodes, and an elastic self-adhesive bandage. Based on the flexible and efficient knitting technology, the sensor has the advantages of low cost, flexibility, simple structure, and convenient large-area manufacturing. Experimental and finite element simulation results show that the knitting pattern of fabric electrodes can enhance the piezoelectric output of ATPS. The optimal ATPS has a high voltage response sensitivity of up to 0.68 V/kPa. The proposed ATPS responds to a wide range of input forces from 0.098 to 724 N in self-powered mode, verifying its feasibility as a tactile sensor for human motion detection and recognition (throat swallowing, wrist bending, elbow bending, knee bending, walking slowly, running fast) and as a pressure sensor (Morse code, digit recognition) and demonstrating its potential for motion tracking, medical rehabilitation, and human-computer interaction.

Non-destructive rapid defect testing around curved head rivets without displacement of eddy current sensors

In the field of aeronautics, it is essential to ensure the structural integrity of aircraft components. Non-destructive testing (NDT) plays a crucial role in ensuring the safety and reliability of structures used in aeronautics as it enables the detection of defects and imperfections without damaging the inspected parts. Domed head rivets are commonly used in aeronautics to assemble multilayer structures due to their strength and ability to maintain the structural integrity of aircraft. However, inspecting these assembly areas can be challenging and presents unique challenges in terms of non-destructive testing due to the curved surface of the rivet, resulting in lift-off variation during surface scanning and a modification of the trajectory of eddy currents near the rivet. This can lead to changes in the response of eddy currents, complicating the accurate interpretation of test results. In recent years, researchers have focused on developing advanced eddy current testing methods to detect defects in complex structures, such as those found in aeronautics. In this work, we propose a promising solution to address both the shape of the rivet and the probe displacement issue during testing. We have developed a model based on the finite element method (FEM) using COMSOL Multiphysics for non-destructive testing through 3D imaging using a matrix of multiplexed multi-element eddy current sensors distributed over multiple layers around the rivet without the need for the displacement of this matrix and capable of adapting to the variation in the diameter of the domed head rivet. The non-displacement of the sensors eliminates parasitic signals that can lead to errors in the interpretation of obtained signals, and the multiplexed powering of the sensors eliminates the mutual inductance effect between adjacent coils.

A novel speed sensor‐less stator flux‐oriented vector control of dual‐stator induction generator for grid‐tied wind energy conversion system

AbstractThe paper proposes a novel speed sensor‐less stator flux‐oriented vector control of dual‐stator induction generator suitable for high‐power applications in grid‐tied wind energy conversion system. In this control strategy, the magnitude and angle of the flux are directly estimated by the measured stator voltages and currents. As the voltage and current sensors are placed on the stationery stator part, therefore, the proposed control strategy does not affect the robustness of the machine compared to the conventional rotor flux‐oriented vector control where the sensors need to be mounted on the rotating part of the machine. Moreover, the proposed speed encoder‐less stator flux‐oriented vector control eliminates the use of speed encoder, thereby reducing the cost and eliminating the error caused due to faulty speed measurement by the speed encoder of the overall system. The performance of the novel speed sensor‐less stator flux‐oriented vector control scheme has been verified by simulation and then experimentally on a 2 hp, 415 V, 50 Hz, three‐phase dual‐stator induction generator drive. The control strategy was implemented through dSPACE 1104 DAC card. From the simulated and the experimental results, it is evident that the proposed control strategy reflects improved performance w.r.t. conventional rotor flux‐oriented vector control.

Verification of the MLP network-based current sensor fault classifier for vector-controlled AC motor drives

In modern drive systems, the aim is to ensure their operational safety. Damage can occur not only to the components of the motor itself but also to the power electronic devices included in the frequency converter and the sensors in the measurement circuit. Critical damage to the electric drive that makes its further exploitation impossible can be prevented by using fault-tolerant control (FTC) algorithms. These algorithms are very often combined with diagnostic methods that assess the degree and type of damage. In this paper, a fault classification algorithm using an artificial neural network (ANN) is analysed for stator phase current sensors in AC motor drives. The authors confirm that the investigated classification algorithm works equally well on two different AC motors without the need for significant modifications, such as retraining the neural network when transferring the algorithm to another object. The method uses a stator current estimator to replace faulty sensor measurements in a vector control structure. The measured and estimated currents are then subjected to a classification process using a multilayer perceptron (MLP), which has the advantage of a small structure size compared to deep learning structures. The uniqueness of the method lies in the use of data in the training set that are not dependent on the parameters of a specific motor. Four types of current sensor faults were studied, namely total signal loss, gain error, offset, and signal saturation. Simulations were performed in a MATLAB/SIMULINK environment for drive systems with an induction motor (IM) and a permanent magnet synchronous motor (PMSM). The results show that the algorithm correctly evaluates the type of damage in more than 99.6% of cases regardless of the type of motor. Therefore, the results presented here may help to develop universal diagnostic methods that will work on a wide variety of motors.

Impact factor on the measurement stability of Roche's coil

Compared with the traditional electromagnetic current sensor, Roche coil has advantage in no magnetic saturation phenomenon, simple structure, and has been widely used in current measurement. However, the measurement accuracy, bandwidth and sensitivity of Roche coils are still affected by a variety of factors, and the problem in ensuring the stability of the measurement system of Roche coils still remains to be a problem nowadays. This article is a review of how each factor affects the measurement stability of Rochester coils. In addition, Roche coils also have certain limitations, such as not being able to directly measure the size of the DC current for the principle of current mutual inductance , in order to make Roche coils to obtain a wider range of applications, this article mentions the zero-drift adjustment method, the method of AC superposition, the use of differential coils, and the method of the Hall effect sensor, which are of guiding significance for the future design of Roche coils capable of measuring DC currents.

Development of a Home Energy Conservation System Using Power Saving Modes

Energy conservation has become more and more popular in recent years, both on the supply and demand sides. This is sponsored majorly by the rising price of energy production affecting both residential homes and industrial sectors. This project proposes a home energy conservation system using three different energy saving modes such as free, normal and extreme modes of operation. Energy was save based on mode of operation using different parameter as the limiting factors that include time, temperature and current respectively. The system comprises of temperature sensor, motion sensor, current sensor, real time clock, 4x4 keypad, LCD screen and an Arduino microcontroller. The Free mode makes use of time limiting factor to alter the time on and off of output, the Normal mode makes use of temperature sensor and motion sensor to regulate the outputs and the Extreme mode males use of current limiting capability to regulate outputs. The project was designed with the proteus software, while the programming was done on the Arduino IDE software. Result of this project shows the system can help conserve up to 45% energy depending on user’s preference.

The Performance of a Passive Autoranging Method for a Photonic Current Transducer.

This paper reports on the testing and evaluation of a passive autoranging (AR) method designed to dynamically extend the measurement range of a photonic current transducer (PCT) to pave the way toward a realization of a combined metering- and protection-class current sensor. The PCT utilizes a current transformer (CT), a piezoelectric transducer (PZT), and a fiber Bragg grating (FBG) to enable current measurement at multiple points in an electrical power network whereby multiple sensors are deployed and interrogated serially using a single optical fiber. The autoranging technique relies on incorporating static MOSFET switches to instantaneously short individual serially connected CT burdens in response to a measured current magnitude exceeding pre-set thresholds. The AR circuit switching events produce distinctive signal features that are used by the proposed switching algorithm to apply appropriate scaling factors to reconstruct the measured current from the optical signal. It is shown through laboratory experiments that the AR circuit correctly reacts to pre-set burden current thresholds of 130% of the nominal value and 22 times the nominal value, signifying its "metering" and "protection" range boundaries. The circuit reaction time is below 4 ms, rendering it suitable for standard power system protection purposes. Moreover, the operation of the AR circuit is demonstrated for burden currents of up to 100 A for over 1 s, satisfying a test procedure for the secondary CT circuit, as required by some power system operators. It is demonstrated that the proposed switching algorithm allows for a correct reconstruction of the burden currents from the optical signal acquired by the FBG interrogator, offering the potential to realize a dual-class optical current sensor.

Salt gradient enhanced sensitivity in nanopores for intracellular calcium ion detection

Intracellular calcium ion detection is of great significance for understanding the cell metabolism and signaling pathways. Most of the current ionic sensors either face the size issue or sensitivity limit for the intracellular solution with high background ion concentrations. In this paper, we proposed a calmodulin (CaM) functionalized nanopore for sensitive and selective Ca2+ detection inside living cells. A salt gradient was created when the nanopore sensor filled with a low concentration electrolyte was in contact with a high background concentration solution, which enhanced the surface charge-based detection sensitivity. The nanopore sensor showed a 10 × sensitivity enhancement by application of a 100-fold salt gradient, and a detection limit of sub nM. The sensor had a wide detection range from 1 nM to 1 mM, and allowed for quick calcium ion quantification in a few seconds. The sensor was demonstrated for intracellular Ca2+ detection in A549 cells in response to ionomycin.

Integrated Fibrous Iontronic Pressure Sensors with High Sensitivity and Reliability for Human Plantar Pressure and Gait Analysis.

Flexible sensing systems (FSSs) designed to measure plantar pressure can deliver instantaneous feedback on human movement and posture. This feedback is crucial not only for preventing and controlling diseases associated with abnormal plantar pressures but also for optimizing athletes' postures to minimize injuries. The development of an optimal plantar pressure sensor hinges on key metrics such as a wide sensing range, high sensitivity, and long-term stability. However, the effectiveness of current flexible sensors is impeded by numerous challenges, including limitations in structural deformability, mechanical incompatibility between multifunctional layers, and instability under complex stress conditions. Addressing these limitations, we have engineered an integrated pressure sensing system with high sensitivity and reliability for human plantar pressure and gait analysis. It features a high-modulus, porous laminated ionic fiber structure with robust self-bonded interfaces, utilizing a unified polyimide material system. This system showcases a high sensitivity (156.6 kPa-1), an extensive sensing range (up to 4000 kPa), and augmented interfacial toughness and durability (over 150,000 cycles). Additionally, our FSS is capable of real-time monitoring of plantar pressure distribution across various sports activities. Leveraging deep learning, the flexible sensing system achieves a high-precision, intelligent recognition of different plantar types with a 99.8% accuracy rate. This approach provides a strategic advancement in the field of flexible pressure sensors, ensuring prolonged stability and accuracy even amidst complex pressure dynamics and providing a feasible solution for long-term gait monitoring and analysis.

Temperature dependence of constant current hot-film sensors: Investigation with application to temperature correction for wall-shear stress measurements

Hot-film sensors measure wall-shear stress based on the forced convective heat transfer. Variations of ambient temperatures lead to significant measurement errors for such thermal sensors and must be corrected for sometimes. Although methods for correcting the temperature shifts of hot-film sensors driven in constant temperature or constant voltage mode have been suggested over the years, the temperature dependence and relevant correction schemes of constant current mode of operation are still open questions. In this study, temperature dependence characteristics of constant current hot-film sensors are investigated within relatively large temperature changes in air and water channel flows (28 °C and 16 °C, respectively). The specific property of constant overheat ratios under varying temperatures for constant current driving mode is found and a quite simple temperature correction function is derived on that basis to eliminate the temperature dependence without any assumed heat transfer correlation. With the correction function, the data at different ambient temperatures are collapsed to single curves with high R2 factors over 0.99, typically. Furthermore, after correction, the relative errors of the measured wall-shear stress are reduced to within ±6 % of the true values. It will then enable the constant current hot-film sensors to calibrate at only one ambient temperature instead of a multiple range of temperatures as with many other schemes, which is more practical and convenient.

Magnetic Proof Mass Configurations to Reduce Spatial Dependency of Piezomagnetic AC Current Sensors

Magnetic Proof Mass Configurations to Reduce Spatial Dependency of Piezomagnetic AC Current Sensors

An improved multi-frequency eddy current array sensor for detecting micro-defects of welding seam in metal plates

This study proposes an improved multi-frequency eddy current array sensor for the accurate detection of micro-defects (under-welding, over-welding, partial welding breakage, and minute penetration holes) of welding seam in metal plates. The primary goal is to further reduce the external and internal noise of the induced coil by optimizing the composition structure of the eddy current probe, thereby improving its sensitivity and signal-to-noise ratio in micro-defect detection. In response to the issue of external noise, this research introduces a gradient differential coil model, which can compensate for initial errors based on a geometrically balanced structure. By establishing a 3D simulation model and a physical mechanical structure, the suppression effect of this structure on excitation magnetic field and external environmental interference is verified. Furthermore, for the internal noise, a mathematical model of the direct stranded litz wire is established. Theoretical calculations and experimental validation confirm that the litz wire exhibits lower eddy current loss and higher Q value compared to traditional copper conductors, thus mitigating internal noise and improving signal-to-noise ratio. On this basis, the excitation mode of the eddy current coil probe array is set to a multi-frequency excitation method based on a center frequency, greatly reducing the electromagnetic interference between channels. Experimental results demonstrate that the improved eddy current sensor can effectively recognize as low as Φ1 mm weld penetration defect at a lift-off value of 0.5 mm, achieving a remarkably high signal-to-noise ratio of approximately 17.7 dB.

Crosstalk in an uncompensated gapped-core contactless current transducer

A detailed analysis of the crosstalk in an uncompensated gapped-core current transducer is presented in this paper. A cut-core current transducer with a magnetic field sensor in the airgap is widely used to measure current in industry and in laboratories. Crosstalk is the effect of a nearby current-carrying conductor on the reading of this type of sensor. We present a study of the dependence of the crosstalk on the position of the external conductor, the core material, and the core geometry, including the number of airgaps. A 3D Finite Element Method (FEM) based model is used to analyze the crosstalk, and the results are compared with measurements.Using a low-permeability ferrite core with two 2 mm airgaps and a single Hall sensor results in a maximum crosstalk error of 18 %. This error can be reduced to 1 % either by using a differential Hall sensor pair, or surprisingly by using a single 4 mm airgap. This error can be further reduced to 0.15 % by using an FeSi core with larger permeability. However, this type of sensor is very sensitive to the position of the Hall sensor in the center of the airgap. Displacement or an angular mismatch can increase the error to 1.5 %, as demonstrated on a commercial sensor.

Simulation Of Electrical Load With An Over Load System Shedding

A break in one of the circuits in a double circuit transmission network system can cause the system to overload. Where excess load on the transmission network system can cause quite dangerous impacts. The Over Load Shedding system is a protection system for the electric power transmission network which aims to prevent widespread blackouts by removing certain predetermined loads. By using the Arduino Mega 2560 as a control center, security against load abnormalities can be carried out and can be monitored automatically using Scada, apart from that, PMT taping for load balancing can also be done using Scada. The Arduino Mega 2560 will read the current on each phase wire using the ACS712 current sensor to detect the load of one of the circuits to be aware of whether it is overloaded or not. This simulator tool has carried out several measurements and tested how to operate it. This tool has a fairly high level of work accuracy, reaching 85% success in operation. So it is hoped that this tool can provide knowledge to the wider community about over load shedding systems in maintaining the electric power transmission system properly and easily to understand.

Dichotomous dynamics of magnetic monopole fluids

A recent advance in the study of emergent magnetic monopoles was the discovery that monopole motion is restricted to dynamical fractal trajectories [J. N. Hallén et al., Science 378, 1218 (2022)], thus explaining the characteristics of magnetic monopole noise spectra [R. Dusad et al., Nature 571, 234 (2019); A. M. Samarakoon et al., Proc. Natl. Acad. Sci. U.S.A. 119, e2117453119 (2022)]. Here, we apply this novel theory to explore the dynamics of field-driven monopole currents, finding them composed of two quite distinct transport processes: initially swift fractal rearrangements of local monopole configurations followed by conventional monopole diffusion. This theory also predicts a characteristic frequency dependence of the dissipative loss angle for AC field-driven currents. To explore these novel perspectives on monopole transport, we introduce simultaneous monopole current control and measurement techniques using SQUID-based monopole current sensors. For the canonical material Dy2Ti2O7, we measure [Formula: see text], the time dependence of magnetic flux threading the sample when a net monopole current [Formula: see text] is generated by applying an external magnetic field [Formula: see text] These experiments find a sharp dichotomy of monopole currents, separated by their distinct relaxation time constants before and after t ~[Formula: see text] from monopole current initiation. Application of sinusoidal magnetic fields [Formula: see text] generates oscillating monopole currents whose loss angle [Formula: see text] exhibits a characteristic transition at frequency [Formula: see text] over the same temperature range. Finally, the magnetic noise power is also dichotomic, diminishing sharply after t ~[Formula: see text]. This complex phenomenology represents an unprecedented form of dynamical heterogeneity generated by the interplay of fractionalization and local spin configurational symmetry.

Development and Application of PIKH-Type Current Sensors to Prevent Improper Opening of Parallelly Connected DC Vacuum Circuit Breakers

This article describes the development of current sensors used in DCU-type high-speed circuit breakers. DCU-type circuit breakers use the principle of turning off a constant short-circuit current by means of countercurrent. The article presents a new current sensor design called PIKh, which uses Hall sensors to measure current and determine its direction. PIKh sensors allow parallel operation of high-speed circuit breakers during the “parking” operation. The article includes the algorithm and principle of operation of the PIKh sensor. The proposed solution was verified on an electric traction vehicle.

Desain Human Machine Interface (HMI) Pada Sistem Pencetak Genteng Otomatis

Roof Tile Printing Machines are important equipment in the industry for printing roof tiles and managing the roof tile production process. This tile printing machine includes a press machine and conveyor that can be adjusted so that the system can operate optimally during production. Operating a tile printing machine requires a program that can control various machine functions, such as conveyor motors and pneumatic cylinders. These programs are generally implemented using a Programmable Logic Controller (PLC). Therefore, an automatic tile printing system based on PLC and HMI with pressure and current parameters was created. This system can control and monitor the tile printing system while operating via the HMI screen. This method is used to collect data related to working methods, diagrams, cable connections, PLC programs, and data management in the HMI. One method used involves components such as limit switches, pressure sensors, current sensors, and pneumatics. The data generated from these processes is processed in the PLC and displayed on the HMI screen. The results obtained from this system are capable of monitoring the tile printing process in real time via the HMI screen.

Smart and Intelligent Weather Adaptive Street Lighting System Using IoT

In this paper, an Internet of Things (IoT)- based smart and intelligent weather-adaptive street lighting system containing an Arduino UNO, an ESP 8266, an LDR, a voltage sensor, a current sensor, a PIR, a relay, and a mobile or web application is designed and implemented. This project's primary goal is to create an intelligent and adaptable street lighting system that will guarantee constant lighting for rural residents. This project is to minimize the electricity losses, reduce the manpower used in manually switching on-off the street lights and & energy cost. There are three primary parts to the system: An Arduino NANO, ESP 8266 is a Wi-Fi module for signal transfer and a smart phone that can operate web page servers. These days, consumers are searching for smart systems that require less maintenance and use less energy. This intelligent street light only turns on when needed, and it continues to run on its own subsequent evenings even in the absence of sunlight. Furthermore, an Arduino NANO was used to include a PIR sensor, which detects motion and turns on the lights to bright mode by turning on more lights. Taking those factors into account, these smart streetlights are equipped with an Internet of Things (IoT) powered adaptive system that can detect malfunctions and send message to parent system.

Non-destructive testing by eddy current sensor for crack orientation detection using HHO optimizer by differential probe

In this research, the design of non-destructive eddy current evaluation systems was improved using Harris Hawks optimization (HHO). To determine the orientation of cracks from eddy current data, a numerical approach was developed based finit elements methode FEM and on an iterative inversion technique that minimizes a non-linear least squares objective function that evaluates the overall difference between forecasts and observationsin axisymmetric model. In this paper the HHO optimization and steepest descent methods were compared and studied in order to minimize the objective function. To measure the precision of the estimated crack orientation, the lower bounds of the HHO optimization on crack orientation were obtained. This work explores the concept of an HHO algorithm that searches for the optimal solution within a large solution space for a specific crack orientation problem.The algorithm starts its search at any point in the solution space and looks for better solutions by searching in the "local" area surrounding the start point. The algorithm ends when it finds what it believes to be the best solution or when predetermined stopping criteria are met.