Bluetooth Low-Energy Current Sensor Compensated Using Piecewise Linear Model

( Jung-won Shin ) 한국센서학회 2020 센서학회지 Vol.29 No.5

Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.

Design of Magnetic Shield for Hall-Effect Current Sensor Using Integrated Magnetic Concentrator

Hongsik Hwang,Junghyun Cho,Cheewoo Lee 한국조명·전기설비학회 2020 조명·전기설비학회논문지 Vol.34 No.3

This paper proposes a shield shape design for minimizing the integrated magnetic concentrator (IMC) hall current sensor shield. Inside flux density and outside magnetic field error rate aren’t satisfied with performance by reducing an initial U-shaped IMC hall current sensor shield’s width and height for an IMC hall current sensor minimization. In order to solve the problem, first, inside flux density is decreased by adding air gap in the shield. Second, outside magnetic field error rate is decreased by adding top shield. Finally, suitable shield shape for minimization is designed by adding top middle shield. The minimization design work is reduced the number of experiments by using the orthogonal array table and main effect analysis method, which are one of the methods of the experimental design method. The proposed model satisfied the design considerations, and the shield area is reduced by 83.7% from the initial model, proving that it was a suitable shield shape for minimization.

홀소자 전류센서를 위한 니켈강 코어 소재 특성

김영곤,Kim, Young-Gon 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.8

In this research, the structural, physical and electrical characteristics of Ni-Fe core chosen to minimize the errors of the Hall current sensors were investigated and Hall current sensor using Ni-Fe core was fabricated. In the result, the fabricated Ni-Fe sample exhibited the maximum hardness about 29.5 GPa and the low friction coefficient about 0.35, and electrical resistivity over $90mOhm{\cdot}cm$. And also Hall current sensor using the fabricated Ni-Fe core showed linear current-voltage properties for DC current at $25^{\circ}C$ temperature.

Probing Insulator-quantum Hall Transitions by Current Heating

Kuang Yao Chen,N. Aoki,Y. Ochiai,K. A. Cheng,Li-Hung Lin,C. F. Huang,Yu-Ru Li,Yen Shung Tseng,Chun-Kai Yang,Po-Tsun Lin,Jau-Yang Wu,Sheng-Di Lin,C.-T. Liang 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.1

We report a magneto-transport study on the two-dimensional electron system (2DES) in an Al- GaAs/GaAs heterostructure. The direct insulator to quantum Hall conductor transition is observed at low temperatures by increasing the magnetic field B perpendicular to the 2DES. We can also observe the transition by varying the current I and find a relation Te~Ia between electron effective temperature Te and current. Here, a denotes the exponent for the power law. The exponent a, however, can have different values on the two sides of the transition point, which indicates different inelastic scattering mechanisms in the low-field insulator and in the quantum Hall conductor. We report a magneto-transport study on the two-dimensional electron system (2DES) in an Al- GaAs/GaAs heterostructure. The direct insulator to quantum Hall conductor transition is observed at low temperatures by increasing the magnetic field B perpendicular to the 2DES. We can also observe the transition by varying the current I and find a relation Te~Ia between electron effective temperature Te and current. Here, a denotes the exponent for the power law. The exponent a, however, can have different values on the two sides of the transition point, which indicates different inelastic scattering mechanisms in the low-field insulator and in the quantum Hall conductor.

Residual magnetic field profiles and their current density profiles of coated conductors for fast and slow cut-off current operations

Sun, J.,Tallouli, M.,Shyshkin, O.,Hamabe, M.,Watanabe, H.,Chikumoto, N.,Yamaguchi, S. The Korea Institute of Applied Superconductivity a 2015 한국초전도저온공학회논문지 Vol.17 No.1

Coated conductor is an important candidate for power cable applications due to its high current density. Even for DC power cable transmission, we must study the transport properties of HTS tapes after slow and fast discharge. In order to evaluate relation of the magnetic field with applied current we developed a scanning magnetic field measurements system by employing a Hall probe. This work presents the measurements of the magnetic fields above a coated conductor by varying applied current pattern. In the work, a transport current of 100 A, less than the critical current, is applied to YBCO coated conductor. We measured the residual magnetic field distributions after cut off the transport current with slow and fast operations. The results show differences of the magnetic field profiles and the corresponding current profiles by an inverse solution from the magnetic field measurement between these two operations because of the hysteresis of coated conductor excited by the transport current.

홀센서를 사용한 펄스와전류탐상 신호의 수치모델링 및 코일센서 신호와의 특성 비교

신영길(Young Kil Shin) 한국비파괴검사학회 2016 한국비파괴검사학회지 Vol.36 No.6

펄스와전류탐상에서 탐상 신호는 주로 센서코일에 유도되는 기전력의 시간에 따른 변화를 측정하여 사용되었는데, 최근에는 홀센서(Hall sensor)로 측정한 신호를 사용하는 경우도 많아지고 있다. 본 논문에서는 펄스와전류탐상에서 나타나는 홀센서 신호를 수치적으로 모델링하여 예측하였다. 이를 위해 두께 측정을 위한 탐촉자를 설계하고 먼저 계단입력전류를 사용한 수치해석을 수행하여 홀센서를 사용하였을 경우의 신호를 예측하였다. 또한, 코일을 센서로 사용하였을 경우의 신호도 동시에 계산하였다. 수치모델링 결과로 예측된 홀센서 신호들은 실험 연구를 통해 보고된 신호들과 유사한 형태를 가지고 있음을 확인할 수 있었다. 그리고 피검사체의 두께 변화에 따른 두 신호들의 특성을 분석하고 비교해 본 결과, 홀센서 신호에서는 코일센서 신호에 비해 두께 변화를 판별하기 위한 정보가 더 적게 제공된다는 것을 알 수 있었다. 펄스입력전류를 사용한 경우의 탐상 신호들도 계산해 본 결과, 두 신호 모두 사용된 펄스의 폭이 지난 시간에는 계단입력전류를 사용한 경우의 응답이 반대가 되어 감소하는 형태로 나타난다는 것을 확인할 수 있었다. Pulsed eddy current (PEC) testing signals have typically been obtained from the electromotive force induced in a sensor coil. However, an increasing number of studies have elected to incorporate the Hall plate as a sensor. Thus, accurate numerical modeling of the Hall sensor signal is necessary. In this study, a PEC probe is designed and a numerical modeling program is written so that Hall sensor signals and coil sensor signals can be calculated simultaneously. First, a step current is used as the input current. The predicted Hall sensor signals show similar characteristics to those of the experimental signals reported by other researchers. The characteristics of the two types of signals are then analyzed and compared as the thickness of test object changes. The results show that the Hall sensor signal provides less information for evaluating the thickness of the test object than the coil sensor signal. The response signals from a pulsed input current are also calculated, and it is confirmed that an equivalent reversed signal pattern appeared after the pulse width at both signals.

Planar Hall Resistance Sensor for Monitoring Current

KunWoo Kim,Sri Ramulu Torati,Venu Reddy,SeokSoo Yoon 한국자기학회 2014 Journal of Magnetics Vol.19 No.2

Recent years have seen an increasing range of planar Hall resistive (PHR) sensor applications in the field of magnetic sensing. This study describes a new application of the PHR sensor to monitor a current. Initially, thermal drift experiments of the PHR sensor are performed, to determine the accuracy of the PHR signal output. The results of the thermal drift experiments show that there is no considerable drift in the signals attained from 0.1, 0.5, 1 and 2 mA current. Consequently, the PHR sensor provides adequate accuracy of the signal output, to perform the current monitoring experiments. The performances of the PHR sensor with bilayer and trilayer structures are then tested. The minimum detectable currents of the PHR sensor using bilayer and trilayer structures are 0.51 μA and 54 nA, respectively. Therefore, the PHR sensor having trilayer structure is the better choice to detect ultra low current of few tens nanoampere.

Hall Current and Viscous Dissipation Impact on MHD Mixed Convection Flow towards a Porous Exponentially Surface with its Engineering Applications

Aaqib Majeed,Ahmad Zeeshan,Aqila Shaheen,Mohammed Sh. Alhodaly,Farzan Majeed Noori 한국자기학회 2022 Journal of Magnetics Vol.27 No.2

Power generators, Hall accelerators, and flight MHD all require high levels of Hall current. The influence of Hall current and viscous dissipation on time-independent hydro-magnetic mixed convective radiative flow across a porous heated surface has thus been investigated using numerical computing and mathematical modeling in the current study. The fluid is electrically conducted and varies exponentially. It is assumed that the wall temperature and elongation rate will vary with specific exponential shapes. A solid uniform magnetic field B0 is employed normally to the surface. The mathematical model of PDEs for incompressible flow is transformed into ODE by applying a numerical technique based on a finite-difference structure which includes a three-stage Lobatto IIIa scheme with the help of MATLAB. The obtained solution depends on the convergence constraints involving the radiation parameter R, magnetic parameter M, porosity parameter Ω, Hall parameter m, buoyancy parameter ε, temperature distribution parameter a, Eckert number Ec, Prandtl number Pr, and convective term bh. Graphs of the velocity and temperature profiles are explained via pertinent parameters. Skin friction factor, and Nusselt number are also evaluated and presented graphically and in tabular form. Results clarify that temperature profile reduces by increasing values of temperature distribution parameter whereas opposite behavior is noted for positive values of the buoyancy parameter.

저온주사홀소자현미경 (LTSHPM)을 이용한 YBCO 초전도박막의 자기적 특성 및 전류분포

이상봉,김종만,이형철 한국물리학회 2009 새물리 Vol.58 No.2

A scanning Hall probe microscope has been used to map the distribution of the magnetic flux in YBCO strips carrying magnetization currents at 77 K. Both the shielded and the trapped fields were studied as functions of the applied field and the transport current. We scanned a wide area of the thin film, by using 2D and 1D methods. The results of the Hall probe magnetic measurements were used in an inverse calculation to obtain the current distribution across the filaments. We analyze our data by using a critical state model to calculate the current distribution and to solve the normalized inversion problem. 저온주사홀소자현미경 (Low temperature scanning Hall Probe Microscope)으로 77 K에서 필라멘트 구조로 된 YBCO 박막의 자기적 특성을 공간적으로 분해하여 관측하였다. 외부에서 가해준 자기장과 인가한 전류의 변화에 따른 YBCO 초전도체의 자기적 특성의 의존도를 연구하고, 그 결과를 바탕으로 역변환 방법을 통한 전류의 공간적 분포를 관측하였다.

Current annealing behavior in suspended graphene

Nam Youngwoo 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.79 No.1

Current annealing behaviors that directly contribute to excellent electrical transport properties in suspended graphene devices are investigated. All successful annealing data for various thicknesses of graphene exhibit three different stages in current–voltage curves upon bias voltage application: (1) sublinear increase in current, (2) abrupt current decrease, and (3) current saturation. This can be attributed to the phonon effect and the structural deformation of graphene at high temperatures induced by Joule heating. It is observed that cleaning occurred primarily in the last stage when the current becomes saturated.