3.4.4 - High Performance Current Measurement with Low-Cost Shunts by means of Dynamic Error Correction

Event
18. GMA/ITG-Fachtagung Sensoren und Messsysteme 2016
2016-05-10 - 2016-05-11
Nürnberg, Germany
Chapter
3.4 Elektrische Messtechnik
Author(s)
P. Weßkamp, J. Melbert - Ruhr-Universität Bochum, Bochum (Germany)
Pages
224 - 230
DOI
10.5162/sensoren2016/3.4.4
ISBN
978-3-9816876-0-6
Price
free

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 coefficient are utilized. In this work, a compensation method is presented which takes static and dynamic temperature drift effects into account and allows a correction of the 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 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%. The proposed dynamic error correction algorithm therefore allows high measurement accuracy despite the use of low-cost shunt resistors.

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