ISBN 9783843950701

978-3-8439-5070-1, Reihe Elektrotechnik

Benyamin Heryanto Rusanto
Development of a primary measurement method to characterise low-impedance reference standard

99 Seiten, Dissertation Technische Universität Braunschweig (2022), Softcover, A5

Zusammenfassung / Abstract

Impedance standards having impedance values in the low mΩ range, with non-zero reactances, and operable with AC-currents of a few Amps and up to a few kHz are needed for appropriate impedance meter calibration. These challenging operation parameters are most relevant for electrochemical impedance spectroscopy of high energy Li-ion battery cells. We present a primary measurement method that can be used for the characterisation of respective impedance standards traceable to the SI.

This thesis describes the development of a primary measurement method to characterise low-impedance reference standard. Basically, two calibrated high precision DC voltage meters are used to measure AC voltages across a characterised reference resistor and the impedance standard. The measured voltages are fitted with sin waves and the complex impedance value is calculated from the amplitudes and phase difference of the voltage curves. Therefore, this research begins with determining the optimum parameters in using DMM for DC voltage sampling and determining the effective synchronization technique of two DMMs so as to obtain precise phase measurement results. Acquisition software development is also carried out to control all instruments and carry out continuous measurements based on a predetermined frequency list.

We present the measurement results of a reference impedance standard in mΩ range, including a full uncertainty budget. Moduli of the measured impedances are compared with those of another method that has been presented recently. The results are equivalent up to 1 kHz and within a relative expanded uncertainty of around 0.47 %.