AMR current measurement device

Mlejnek, Pavel; Vopálenský, Michal; Ripka, Pavel

doi:10.1016/j.sna.2007.10.016

Cited by 68 publications

(46 citation statements)

References 5 publications

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“…Extensive investigations have been performed on multilayers due to important applications in data storage and magnetic sensors [3]. Nowadays, the new field of spin-caloritronics [ 4 , 5 ] addresses the combination of thermoelectricity and spintronics and has led to an increased interest in magneto-thermoelectric effects.…”

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confidence: 99%

Magnetothermoelectric figure of merit of Co/Cu multilayers

Krzysteczko

Liebing

et al. 2014

Appl. Phys. Lett.

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The switching of the magnetization configurations of giant magnetoresistance multilayer stacks not only changes the electric and thermal conductivities, but also the thermopower. We study the magnetotransport and the magneto-thermoelectric properties of Co/Cu multilayer devices in a lateral thermal gradient. We derive values of the Seebeck coefficient, the thermoelectric figure of merit, and the thermoelectric power factor. The Seebeck coefficient reaches values up to -18 µV/K at room temperature and shows a magnetic field dependence up to 28.6 % upon spin reversal.In combination with thermal conductivity data of the same Co/Cu stack, we find a spin dependence of the thermoelectric figure of merit of up to 65 %. Furthermore, a spin dependence of the power factor of up to 110 % is derived.

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confidence: 99%

Magnetothermoelectric figure of merit of Co/Cu multilayers

Krzysteczko

Liebing

et al. 2014

Appl. Phys. Lett.

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“…In fact, some studies [30][31][32] also proposed symmetrical arrangement methods to improve the accuracy of current measurement with different kinds of magnetic field sensors. However, a three-phase system is not taken into consideration.…”

Section: Hall-based Electronic Current Transformermentioning

confidence: 99%

A Redundancy Mechanism Design for Hall-Based Electronic Current Transformers

et al. 2017

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Abstract:Traditional current transformers (CTs) suffer from DC and AC saturation and remanent magnetization in many industrial applications. Moreover, the drawbacks of traditional CTs, such as closed iron cores, bulky volume, and heavy weight, further limit the development of an intelligent power protection system. In order to compensate for these drawbacks, we proposed a novel current measurement method by using Hall sensors, which is called the Hall-effect current transformer (HCT). The existing commercial Hall sensors are electronic components, so the reliability of the HCT is normally worse than that of the traditional CT. Therefore, our study proposes a redundancy mechanism for the HCT to strengthen its reliability. With multiple sensor modules, the method has the ability to improve the accuracy of the HCT as well. Additionally, the proposed redundancy mechanism monitoring system provides a condition-based maintenance for the HCT. We verify our method with both simulations and an experimental test. The results demonstrate that the proposed HCT with a redundancy mechanism can almost achieve Class 0.2 for measuring CTs according to IEC Standard 60044-8.

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“…A circular sensor array with 6 and more sensors around the conductor approximates better the closed line integral in Ampere's law. The circular sensor array improves the resistance against the position of the measured conductor [9] and also against the external magnetic field and current in external conductors [10]. Both errors decrease with increasing number of sensors, and eight sensors are considered as an optimum number.…”

Section: Introductionmentioning

confidence: 99%

“…The measured conductor is positioned inside the hole perpendicularly to the sensor plane. The number of sensors was chosen as a compromise between the complexity of the device and the suppression of error caused by the off-center position of the current [9]. All the sensors are placed on a circle whose radius is = 12.7 mm and the measurement hole is 10 mm in diameter.…”

Section: Introductionmentioning

confidence: 99%

Off-Center Error Correction of AMR Yokeless Current Transducer

Mlejnek

Ripka

2017

Journal of Sensors

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We present a method of calibration and error correction of the AMR yokeless current transducer consisting of a circular array of eight anisotropic magnetoresistors (AMR) with one feedback compensation loop. The main sources of errors are the nonidentical parameters of AMR sensors and off-center position of the measured current. It is well known that AMR sensors from the same batch have 2% spread of the sensitivity; we found that the variation of the factor of the internal compensation coil is the same. We developed a novel calibration process using the readings of individual residual uncompensated voltages of the AMRs. The position of the current inside the measurement hole is estimated from the individual voltages considering the influence of external DC magnetic field such as the Earth's field. During the calibration phase, the sensor outputs are measured for several positions of the current conductor inside the measuring hole. As a result of calibration the lookup table of error corrections is calculated and stored in the memory, and then these values are used for the correction during the measurement of the unknown current. This procedure reduces the off-center error from 0.4% to 0.06%.

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AMR current measurement device

Cited by 68 publications

References 5 publications

Magnetothermoelectric figure of merit of Co/Cu multilayers

Magnetothermoelectric figure of merit of Co/Cu multilayers

A Redundancy Mechanism Design for Hall-Based Electronic Current Transformers

Off-Center Error Correction of AMR Yokeless Current Transducer

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