Hall Sensor Research Articles

Vibration separation method for permanent magnet guideway irregularity measurement

High-temperature superconducting (HTS) pinning maglev has the potential to achieve high operational speed while having a low maintenance cost, attracting a lot of attention. The HTS pinning maglev system realizes the levitation of the vehicle through the flux pinning characteristics between the high-temperature superconducting bulk and the magnetic field of the permanent magnet guideway (PMG). Thus, the profile of the magnetic field of the PMG can significantly affect the levitation status of the vehicle, which makes the PMG irregularity become one of the main excitation sources of the system. The magnetic induction intensity on the surface of the PMG can be used to characterize the PMG irregularity, but the non-contact dynamic measurement may produce large errors by the vibration of the measurement system during the process. In order to evaluate the PMG irregularity, the vibration component needs to be separated from the overall signal. In this paper, through the synchronous measurement of the Hall sensor and accelerometer, the vibration separation method of the PMG irregularity measurement is simplified to the optimal filter estimation. The particle swarm optimization (PSO) algorithm is used to calculate the parameters of the optimal filter based on the correlation coefficient criterion. The effectiveness of the proposed method is verified by the test. The separated signal is more accurate in both time domain and frequency domain for the characterization of PMG irregularity.

An Enhanced Dynamic Collector Voltage and Current Clamping Method for Semiconductor in Electric Vehicles

The electric drive and the batteries are the two primary parts of an electric vehicle (EV). In order to increase the availability and dependability of the semiconductors used in traction converters, this research focuses on a new approach of semiconductor protection. The IGBT overshoot in voltage during a short circuit situation was successfully reduced by a newly created active voltage and current clamping circuit. This innovative method restricts IGBT’s collector-emitter voltage during the turn-off event. As soon as the collector-emitter voltage of the IGBT crosses a predetermined threshold, the IGBT is partially turned on. The IGBT is then kept operating linearly, minimizing the rate at which the collector current falls and, consequently, and the collector-emitter over voltage. Simultaneously, during the short circuit, the current is monitored by a high precision hall-effect sensor allegro make IC, which detects over current and provides a fault output within 1µs. As a result of the combination of current and voltage monitoring, the likelihood of the IGBT failure is reduced drastically.

Elastic-plastic conductor damage evaluation at over 0.4% strain using a high-stress REBCO coil

Recent reports on screening current stress simulations of high-field REBCO magnets frequently present peak stresses over 1 GPa. However, this result is probably an unrealistic artifact of purely elastic calculations, considering the macroscopic yield and fracture stresses of approximately 900 MPa and less than 1.1 GPa for Hastelloy substrate-coated conductors. Here, we evaluate elastic-plastic conductor damage at over 0.4% strain using a high-stress REBCO coil exposed to a high field to explore this elastic-plastic regime. The coil was located off-center in a low-temperature superconductor magnet so as to induce a significant screening current in the enhanced radial field. Voltage taps, a Hall sensor, and two strain gauges were used for the instrumentation. We obtained strains exceeding 0.4% near the outward edge during the coil current charge from 350 A to 390 A, where the coil was exposed to external axial and radial magnetic fields of 13 T and 0.5 T. Post mortem results showed wavy plastic deformation, electrical damage, and REBCO defects. An elastic-plastic simulation reproduced the measured strains and predicted that ∼1 GPa stress is sufficient to induce ∼0.9% strain, thus validating our initial concerns with purely elastic models. This paper provides our experimental and simulation results.

Very High Temperature Hall Sensors in a Wafer‐Scale 4H‐SiC Technology

Abstract4H‐SiC is a key enabler for realizing integrated electronics operating in harsh environments, which exhibit very high temperatures. Through advances in 4H‐SiC process technology, different sensor and circuit types have been demonstrated to operate stable at temperatures as high as 800 °C, paving the way toward harsh‐environment immune smart sensors. In this work, for the first time the operation of ion‐implanted 4H‐SiC Hall sensors realized in a wafer scale Bipolar‐CMOS‐DMOS technology is demonstrated at a wide operation temperature range spanning room temperature up to 500 °C in addition to short‐term operation up to 600 °C. The temperature‐dependent sensor characteristics of 15–22 samples are evaluated in terms of sensitivity and noise. The small inter‐device variations reflect the stability of the used process for very high temperature Hall sensors. The noise‐limited detectivity is further evaluated, revealing a best value of 950 nT/ and a mean detectivity of 1 µT/ at 500 °C. This is the best value reported up to date for very high temperature Hall sensors, besides being the first demonstration of ion‐implanted wide‐bandgap Hall sensors. Overall, the results reflect the potential of the demonstrated Hall sensors for the next generation of integrated magnetic field sensors in harsh environments.

Fault diagnosis method for redundancy sensors of electric actuator

In order to solve the singular fault modes of redundant position sensors in electric actuators, a fault diagnosis method based on Hall sensor analytical model is proposed on the basis of traditional redundancy comparison algorithm. Through the complete self-monitoring design of Hall sensor and the analytical model design, non-similar redundancy signals of sensors are formed. At the same time, a hypothesis testing method based on sliding data window is adopted, and by adjusting the width of the sliding window to meet the indicators of false alarm rate and missed alarm rate, a fault diagnosis algorithm for position sensors is formed as a whole. Finally, an algorithm validation was conducted for the 2∶2 singular fault mode of the position sensor. The results showed that the fault diagnosis algorithm based on the Hall sensor model can effectively solve the problems caused by 2∶2 singular faults, greatly improve the availability of sensor signals, and ensure the control accuracy and fault tolerance of the servo closed-loop.

Performance of graphene Hall effect sensors: Role of bias current, disorder, and Fermi velocity

Performance of graphene Hall effect sensors: Role of bias current, disorder, and Fermi velocity

Effect of temperature on the stability and performance of III-nitride HEMT magnetic field sensors

The study aimed to investigate the underlying physics limiting the temperature stability and performance of non-surface passivated Al0.34Ga0.66N/GaN Hall effect sensors, including contacts, under atmospheric conditions. The results obtained from analyzing the microstructural evolution in the Al0.34Ga0.66N/GaN Hall sensor heterostructure were found to correlate with the electrical performance of the Hall effect sensor. High-resolution x-ray photoelectron spectroscopy studies revealed the signature of surface oxidation in the GaN cap layer, as well as a slight out-diffusion of “Al” from the AlGaN barrier layer. To prevent the formation of a bumpy surface morphology at the Ohmic contact, we investigated the impact of “Pt” top Ohmic contacts. The application of a top “Pt” contact stack resulted in a smooth Ohmic contact surface and provided evidence that the bumpy surface morphology in Au-based Ohmic contacts is due to the formation of an Al-Au viscous alloy during rapid thermal annealing. In the early stages of thermal aging, the small drop in contact resistivity stabilized with subsequent thermal aging past the initial 550 h at 200 °C. The outcome is that the Al0.34Ga0.66N/GaN Hall effect sensors, even without surface passivation, exhibited a stable response to applied magnetic fields with no sign of significant degradation after 2800 h of thermal aging at 200 °C under atmospheric conditions. This observed stability in the Hall sensor without surface passivation can be attributed to a self-imposed surface oxidation of the cap layer during the early stages of aging, which serves as a protective layer for the device during subsequent extended periods of thermal aging at 200 °C.

Mitigation of Device Heterogeneity in Graphene Hall Sensor Arrays Using Per-Element Backgate Tuning.

Graphene Hall-effect magnetic field sensors (GHSs) exhibit high performance comparable to state-of-the-art commercial Hall sensors made from III-V semiconductors. Graphene is also amenable to CMOS-compatible fabrication processes, making GHSs attractive candidates for implementing magnetic sensor arrays for imaging fields in biosensing and scanning probe applications. However, their practical appeal is limited by response heterogeneity and drift, arising from the high sensitivity of two-dimensional (2D) materials to local device imperfections. To address this challenge, we designed a GHS array in which an individual backgate is added to each GHS, allowing the carrier density of each sensor to be electrostatically tuned independent of other sensors in the array. Compared to the constraints encountered when all devices are tuned with the same backgate, we expected that the flexibility afforded by individual tuning would allow for the array's sensitivity, uniformity, and reconfigurability to be enhanced. We fabricated an array of 16 GHSs, each with its own backgate terminal, and characterized the ability to modulate GHS carrier density and Hall sensitivity within CMOS-compatible voltage ranges. We then demonstrated that individual device tuning can be used to break the trade-off between device sensitivity and uniformity in the GHS array, allowing for enhancement of both objectives. Our results showed that GHS arrays exhibiting >30% variability under single-backgate operation could be compensated using individual tuning to achieve <2% variability with minimal impact on the array sensitivity.

Large-area magnetic skin for multi-point and multi-scale tactile sensing with super-resolution

The advancements in tactile sensor technology have found wide-ranging applications in robotic fields, resulting in remarkable achievements in object manipulation and overall human-machine interactions. However, the widespread availability of high-resolution tactile skins remains limited, due to the challenges of incorporating large-sized, robust sensing units and increased wiring complexity. One approach to achieve high-resolution and robust tactile skins is to integrate a limited number of sensor units (taxels) into a flexible surface material and leverage signal processing techniques to achieve super-resolution sensing. Here, we present a magnetic skin consisting of multi-direction magnetized flexible films and a contactless Hall sensor array. The key features of the proposed sensor include the specific magnetization arrangement, K-Nearest Neighbors (KNN) clustering algorithm and convolutional neural network (CNN) model for signal processing. Using only an array of 4*4 taxels, our magnetic skin is capable of achieving super-resolution perception over an area of 48400 mm2, with an average localization error of 1.2 mm. By employing neural network algorithms to decouple the multi-dimensional signals, the skin can achieve multi-point and multi-scale perception. We also demonstrate the promising potentials of the proposed sensor in intelligent control, by simultaneously controlling two vehicles with trajectory mapping on the magnetic skin.

Pediatric continuous-flow total artificial heart with rotor axial position tracking technology: First report of in vivo assessment

BackgroundThe pediatric continuous-flow total artificial heart (P-CFTAH) is a novel double-ended centrifugal pump designed with the intent to provide circulatory support for pediatric heart failure. ObjectivesTo enable continuous monitoring of pump hemodynamics, Hall effect sensors (HES) were embedded inside the P-CFTAH design to track both axial movement and position of the pump rotor post-implantation. Herein, we report an early in vivo evaluation of the P-CFTAH with HES, implanted in small-sized ovine models. MethodsFive healthy lambs were used for the P-CFTAH implantation via a full median sternotomy and cardiopulmonary bypass support. Successful evaluation of the P-CFTAH was achieved in four out of five (n = 4, 20.9 ± 1.3 kg). The hemodynamics and operating conditions were continuously recorded with varying pump speeds (2,800-5,000 rpm), systemic/pulmonary vascular resistance ratio, and high- and low-volume conditions. Among the four cases, P-CFTAH with HES embedded in the rotor was used in two cases. ResultsAll surgical procedures were uneventful, and the optimal anatomical fit of the pump was shown in the chest. Differences between the left and right atrial pressures were mostly maintained within the intended limit of ± 10 mm Hg throughout the design range of systemic and pulmonary vascular resistance. The HES accurately traced the rotor position, showing a positive correlation with atrial pressure differences. ConclusionsThe findings suggest that the P-CFTAH has the potential to provide self-balancing circulatory support for pediatric heart failure patients. The study contributes to the development of a pediatric-sized total artificial heart with improved monitoring.

Size effect in CoFeB-based anomalous Hall sensor and its applications in pulse detection

Anomalous Hall effect (AHE) sensor has attracted significant attention in recent years due to its simpler structure and better sensitivity as compared to semiconductor-based Hall sensors. However, up to now, most of the work has been focused on its basic functionalities, with very little attention given to optimizing its performance for practical applications. In this work, we systematically investigated how the lateral dimension affects the performance of CoFeB-based AHE sensors. By adjusting the sensor width while keeping the length and other parameters constant, it is found that although the output signal amplitude decreases with increasing the sensor width, the noise and power consumption also decrease simultaneously, leading to an overall enhancement of the sensor performances with a sensitivity, detectivity, and power efficiency of 8960 Ω/T, 205nT/Hz@1Hz, and 2009 V/WT, respectively. To illustrate the potential applications of AHE sensors, we demonstrate a proof-of-concept experiment to showcase the potential AHE sensor in pulse detection.

High-precision measuring device of volt-ampere characteristics

Formulation of the problem. In this paper, the application of the Hall sensor in measuring technology is considered. The hall sensor is used as a measuring element of the volt-ampere characteristics of electrical circuits based on the principle of measuring the electromagnetic field in the area of the conductive pattern on the board in the range of 0 to 30 volts and 0 and 30 amperes. The application of this measurement method allows measuring with an accuracy of up to one thousandth of the measured value, which allows metrological work to be carried out for verification of various types of equipment. The article will be useful for specialists in the field of electronics, electrical engineering and other related fields who are interested in new methods of measuring and controlling the parameters of electrical circuits. Target. The study and analysis of methods of metrological measurements of volt-ampere characteristics using a Hall sensor, their practical application in various fields of science and technology. The proposal of a promising application of the Hall sensor in metrological measuring technology. Results. Three measuring instruments were compared: a developed device based on a Hall sensor, a household multimeter and a Rigol DM3058E, which was taken as a reference. During the experiment, it was concluded that the developed device has a low error. Practical significance. The results of the work can be useful in the further design of metrological devices. This research was funded by Russian Science Foundation, No. 19-79-109, https://rscf.ru/project/19-79-10109 /.

Planar Hall Effect Magnetic Sensors with Extended Field Range.

The magnetic field range in which a magnetic sensor operates is an important consideration for many applications. Elliptical planar Hall effect (EPHE) sensors exhibit outstanding equivalent magnetic noise (EMN) on the order of pT/Hz, which makes them promising for many applications. Unfortunately, the current field range in which EPHE sensors with pT/Hz EMN can operate is sub-mT, which limits their potential use. Here, we fabricate EPHE sensors with an increased field range and measure their EMN. The larger field range is obtained by increasing the uniaxial shape-induced anisotropy parallel to the long axis of the ellipse. We present measurements of EPHE sensors with magnetic anisotropy which ranges between 12 Oe and 120 Oe and show that their EMN at 10 Hz changes from 800 pT/Hz to 56 nT/Hz. Furthermore, we show that the EPHE sensors behave effectively as single magnetic domains with negligible hysteresis. We discuss the potential use of EPHE sensors with extended field range and compare them with sensors that are widely used in such applications.

Switched capacitor voltage boost converter for BLDC motor speed control of electric vehicles

BLDC motors are extensively used in various industries, including CNC machine tools, industrial robots, and electric vehicles. Because of their compact size, high efficiency, high torque-to-power ratios, and low maintenance requirements due to their brushless operation, BLDC motors are the backbone of many industrial automation systems. However, they pose significant challenges when it comes to speed control. In this study, the speed of BLDC motors is controlled by PI-based speed controllers. In the described method, the BLDC motor is commutated using Hall Effect sensors. A proposed approach uses PI to regulate the speed of BLDC motors in an open-loop PWM method. The speed-controlled BLDC motor is analysed using MATLAB/simulink. The hardware of the proposed system is also implemented.

Rancang Bangun Trainer Mesin Cuci Dua Tabung Berbasis Arduino Nano

A washing machine is a crucial device for society as it offers convenience and practicality. However, the efficiency of a washing machine can decline over time, especially in its components which may experience performance degradation or damage. This research involves designing a damage detection tool for washing machines, structured as a trainer operated in simulation form, serving as a learning medium to better understand the systematic functioning of washing machines. This trainer module uses toggle button switches installed on each cable line to simulate various damage conditions. The sensor used in this trainer is the PZEM-004T, which detects the current, voltage, and power used by the AC (Alternating Current) motor. To measure the motor's RPM (Revolutions per Minute) speed, a proximity sensor utilizing the Hall effect principle is employed. The microcontroller used to process the data generated by the sensors is an Arduino Nano, with the data displayed on an LCD (Liquid Crystal Display). In this research, the results based on the PZEM-004T sensor testing showed it could measure voltage, current, and power with an error rate of 7.3% and a success rate of 92.7%. The proximity sensor could measure motor speed with an error rate of 3.4% and a success rate of 96.6%. The main challenge in the monitoring system was the real-time reading on the LCD screen frequently halting due to the long delay required to read the proximity Hall effect sensor values.

An Extensive Review of MR Sensors with Design and Characteristic Evaluation of Three-layered TMR Sensor

Abstract: The reliability and efficacy of sensor-based automated systems have improved due to the proliferation of electric vehicles, renewable sources, and integrated systems in power industries extensively. This has been accomplished by increasing the power density and decreasing the volume of the system. Background: Mathematical estimation and comparative analysis of the physical factors result in massive usage of operational matrices measured using sensors. Magnetic field sensors, used in industries and biomedical applications, have a high level of precision in the evaluation of measurements. In order to extract the measured parameters such as sensitivity, accuracy, operating cost, the linear range of operation, and power utilisation, these sensors adhere to the physical constraints during their nominal working conditions. The characteristics of the aforementioned sensors are enumerated in detail in this article. Objective: This objective is highly focused on providing a comprehensive overview of classification and the properties of Hall-Effect, anisotropic magnetoresistive (AMR), giant magnetoresistive (GMR), and tunnelling magnetoresistive (TMR) sensors. The dissertation on its properties concludes that TMR is more reliable and sensitive in variable operating conditions. Methods: The methods for selecting the sensors for an application are confined to voltage fluctuations and sensitivity. A three-layered TMR sensor with two magnetic layers and an insulator in between is proposed as a significant advancement compared to the literature. The micromagnetic simulation is carried out at room temperature for a three-layered TMR made up of neodymium alloy, magnesium oxide, and cobalt platinum alloy. Conclusion: Based on the studies executed, it is determined that TMR is more sensitive than both conventional and MR sensors. The proposed schematic claims that the higher free layer thickness offers maximum sensitivity with 77% negative magnetoresistance. The reduced coercivity of 1.9Oe is achieved in this combination at a specified temperature range.

A Magnetic Field-Based Wearable Respiration Sensor for Real-Time Monitoring During Pulmonary Rehabilitation.

This work explores Hall effect sensing paired with a permanent magnet, in the context of pulmonary rehabilitation exercise training. Experimental evaluation was performed considering as reference the gold-standard of respiratory monitoring, an airflow transducer, and performance was compared to another wearable device with analogous usability - a piezoelectric sensor. A total of 16 healthy participants performed 15 activities, representative of pulmonary rehabilitation exercises, simultaneously using all devices. Evaluation was performed based on detection of flow reversal events and key respiratory parameters. Overall, the proposed sensor outperformed the piezoelectric sensor with a mean ratio, precision, and recall of 0.97, 0.97, and 0.95, respectively, against 0.98, 0.90, and 0.88. Evaluation regarding the respiratory parameters indicates an adequate accuracy when it comes to breath cycle, inspiration, and expiration times, with mean relative errors around 4% for breath cycle and 8% for inspiration/expiration times, despite some variability. Bland-Altman analysis indicates no systematic biases. Characterization of the proposed sensor shows adequate monitoring capabilities for exercises that do not rely heavily on torso mobility, but may present a limitation when it comes to activities such as side stretches. This work provides a comprehensive characterization of a magnetic field-based respiration sensor, including a discussion on its robustness to different algorithm thresholds. It proves the viability of the sensor in a range of exercises, expanding the applicability of Hall effect sensors as a feasible wearable approach to real-time respiratory monitoring.

Анализ частотных характеристик токовых датчиков цифрового трансформатора тока и напряжения

Digital measuring current and voltage transformers (DCVT), which incorporate various current and voltage sensors are the key sources of information about processes at modern digital substations. Classic small-sized current transformers, Rogowski coils, magnetotransistor sensors, Hall effect sensors, fiber-optic Faraday effect sensors, as well as shunts can be used as current sensors in DCVTs. For redundancy purposes, current channels are performed in several copies and on different sensors. Sensors that are different in nature have their own set of advantages, which together makes it possible to obtain the effect of eliminating the shortcomings of specific sensors. For example, they may not have a saturation effect or transmit the direct current component quite accurately, which is a significant advantage over classic current transformers. At the mains frequency, the behavior of these sensors is predictable, but their behavior is not well studied at higher and lower frequencies. Thus, it is decided to study the frequency response and phase response of these sensors in a wide frequency range. To solve the problems within the framework of this study, physical experiment, analytical and empirical solution methods have been used. As a result of the study, the frequency response and phase response of current sensors of DCVT in a wide frequency range have been obtained. Analog filter has been designed to correct the signal of the magnetotransistor sensor. The results obtained coincide with theoretical data and can be considered when developing digital relay protection and automation algorithms.

Low-Power Magnetic Displacement Sensor Based on RISC-V Embedded System.

With the emergence of RISC-V architecture in embedded devices, its inherent low-power features have propelled its extensive adoption across various industrial settings. Displacement sensors leveraging Hall sensors and magnetic flux measurement present notable benefits including cost-effectiveness and compact design. This study undertakes the porting of Hall sensors onto RISC-V architecture embedded devices, validating their functionality within displacement sensors. Empirical investigations substantiate that the ported system consistently delivers comparable outcomes to those obtained from x86 architecture systems employing PM-MFM methods, affirming its reliability and performance in practical applications.

Optimising signal quality for corrosion detection using the innovative Mag_FSRCNN model to minimise hall sensor array in eddy current testing

ABSTRACT The security of aviation hinges significantly on the strength of aircraft structures, with potential risks arising from issues like corrosion impacting the framework. Eddy current testing (ECT) sensors, particularly those utilising array technology, present a promising solution to address this concern. However, challenges persist in improving the clarity of corrosion signals while optimising associated expenses. In response to this, our study introduces the Mag_FSRCNN model, a novel framework that integrates a Fast Super-Resolution Convolutional Neural Network (FSRCNN) module network with a part of Generator module of Generative Adversarial Network to enhance magnetic images obtained by the ECT sensor array. Mag_FSRCNN surpasses traditional methods, showcasing high-resolution capabilities in enhancing ECT signal images. The model demonstrates excellence when evaluated using metrics such as Structural Similarity Index, Root Mean Square Error, and Peak Signal-to-Noise Ratio. These results significantly contribute to the ongoing progress of ECT sensors, facilitating improved resolution and cost-effective application of Hall sensor arrays in the current evolution of ECT sensor technology.