@phdthesis{Haag2019,
  type      = {Master Thesis},
  author    = {Hermann Haag},
  title     = {Dc biased equivalent series resistance measurement and loss estimation in ferro electric ceramic capacitors},
  journal    = {Messung des {\"a}quivalenten Serienwiderstandes und Verlustbestimmung von ferroelektrischen Keramikkondensatoren unter anliegender Gleichspannung},
  doi       = {10.25924/opus-3148},
  pages     = {73},
  year      = {2019},
  abstract  = {In this thesis the effect of dc voltage bias on the equivalent series resistance (ESR) of capacitors and especially ferroelectric dielectric ceramic capacitors (FDCC) is analysed. Further the influence of the dc biased ESR on the losses of capacitors is investigated. Also piezoelectric resonances (PR) occurring in FDCCs with applied dc bias and their influence on the losses are analysed. Therefore a measurement circuit to measure the impedance and thus the ESR of capacitors in combination with a vector network analyser (VNA) is developed. Using the developed circuit the ESR of capacitors of different technologies is measured and their behaviour with dc bias is evaluated. The losses of an FDCC are measured in a power electronic (PE) circuit with a developed calorimetric measurement system (CMS). The influence of the PR is investigated by tuning the switching frequency of the PE system and thus the frequency of the capacitor current exactly into the PR. The measured losses are then compared to a calculation based on the capacitor current harmonics and the respective ESR. The measurements show an increase of the ESR with dc bias for all measured FDCCs. The loss measurements show a significant increase of the losses in an FDCC if the current frequency matches the PR frequency. Consequently a decrease of the PE system's efficiency is measured. The loss calculations do not exactly match the measurements but there is a systematic deviation of the same order for all measurements.},
  language  = {en}
}