Modeling and simulation of frequency dependent impedance of conductors in wide-band gap applications for power electronics

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Date
2020-12
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University of Alabama Libraries
Abstract

Recent advancement in power electronics requires the design and development of more energy-dense and efficient converter systems, with enhanced power handling capability as well as higher switching operation. The demand and implementation of wide-bandgap semiconductors to meet the above need is on the rise. However, achieving these goals comes with challenges for the power electronic application and system designers. Several problems arise due to the densification of these systems in conjunction with the use of wide-bandgap semiconductors. The high-switching speed of these semiconductors in conjunction with the presence of parasitic elements introduces consequences which can impact power electronic system behavior and lead to system anomalies.This thesis studies the effect of these parasitic elements and identifies skin and proximity effects as the root cause of their frequency-dependence. FEA analysis using COMSOL is used to extract basic conductor impedance parameters across frequency and to show their dependence on frequency. Analysis of the electromagnetic fields inside and around the conductors is also conducted. The resulting predictions are validated through empirical measurements using an impedance analyzer. These results indicate that skin effect alone is responsible for the frequency-dependence of conductor impedance when operated in isolation. On the other hand, both the skin and proximity effects contribute to the frequency-dependence of conductor impedance for the case of closely-spaced conductors. Implementing design schemes for power modules which accounts for these phenomena will result in increased system efficiency, reduced parasitics, and reduced thermal load. Finally, a simple mathematical model is developed that provides good prediction of impedance across frequency with only a few parameters.

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Electronic Thesis or Dissertation
Keywords
Electrical engineering
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