High Frequency Battery Impedance Measurements for EMI Prediction

Mohammad Sami Tabbakh (1) , Florent Morel (2) , Roberto Mrad (2) , Youssef Zaatar (1)

1 Plateforme de Recherche en NanoSciences et NanoTechnoloties
2 EE - Ampère, Département Energie Electrique

In embedded applications which include power converters, the battery that provides the energy is a part of the EMI path. As conducted emissions generated by power converters spread into a large frequency band, the battery characterization should be extended to cover this range of frequencies. In this paper, a method to measure the battery impedance using an impedance analyzer is explained and applied to a cell-phone battery from 1MHz to 100MHz. In this frequency range, measurements show that the battery impedance is unrelated to the battery state of charge and that a model including just inductances and resistances matches very well with the measured behavior. The measured impedance is validated by predicting the frequency spectrum of the battery's voltage when feeding a switched-mode power converter. The converter switches at 1.2MHz and the related harmonics extend beyond 100MHz. The measured and predicted voltages match up to 80MHz.

Mots clés: Switched Mode Power Supply; Cell phone battery; EMI prediction; Battery impedance measurement

Domaines: Energie électrique; Electronique

Mohammad Sami Tabbakh, Florent Morel, Roberto Mrad, Youssef Zaatar. High Frequency Battery Impedance Measurements for EMI Prediction. EMC, Aug 2013, Denver, United States. pp.763-767, ⟨10.1109/ISEMC.2013.6670512⟩. ⟨hal-00862617⟩