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Journal of Sensors and Sensor Systems An open-access peer-reviewed journal
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Volume 5, issue 2
J. Sens. Sens. Syst., 5, 389–400, 2016
https://doi.org/10.5194/jsss-5-389-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Sensors and Measurement Systems 2016

J. Sens. Sens. Syst., 5, 389–400, 2016
https://doi.org/10.5194/jsss-5-389-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Regular research article 08 Nov 2016

Regular research article | 08 Nov 2016

High-accuracy current measurement with low-cost shunts by means of dynamic error correction

Patrick Weßkamp and Joachim Melbert Patrick Weßkamp and Joachim Melbert
  • Institute of Electronic Circuits, Ruhr-Universität Bochum, Bochum, Germany

Abstract. Measurement of electrical current is often performed by using shunt resistors. Thermal effects due to self-heating and ambient temperature variation limit the achievable accuracy, especially if low-cost shunt resistors with increased temperature coefficients are utilized. In this work, a compensation method is presented which takes static and dynamic temperature drift effects into account and provides a significant reduction of measurement error. A thermal model of the shunt resistor setup is derived for this purpose and a suitable calibration method is developed. The correction algorithm is based upon a digital filter bank and is optimized for microcontrollers with low computational complexity. It is implemented in laboratory test equipment for long-term studies on automotive lithium-ion cells. For a 600 A current pulse, it reduces the measurement error from 2 % to less than 0.1 %. Measurements with a real-life testing profile show a reduction of remaining measurement error by 60 %. Statistical results for 100 test systems and long-term drift measurements prove the reliability of the method. The proposed dynamic error correction algorithm therefore allows high measurement accuracy despite the use of low-cost shunt resistors.

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Short summary
Measurement of electrical current is important for many scientific and industrial applications. Often shunt resistors are used. However, thermal effects due to self-heating and ambient temperature variation limit the achievable accuracy. In this work, a dynamic compensation method is presented which takes static and dynamic temperature drift effects into account. It significantly reduces the remaining measurement errors. The approach can also be used to improve existing measurement systems.
Measurement of electrical current is important for many scientific and industrial applications....
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