Wide bandgap (WBG) power semiconductor devices can operate at high voltage, high switching frequency and high temperature. However, the... Show moreWide bandgap (WBG) power semiconductor devices can operate at high voltage, high switching frequency and high temperature. However, the extremely fast switching characteristics, when combining parasitic components from the device package and power electronics circuit, are unfortunately accompanied by undesirable switching oscillations. In this thesis, switching oscillations observed in the WBG devices are studied. Firstly, a survey on oscillations in the general high-frequency power electronics circuit is carried out including the impacts of oscillation, causes of oscillation and mitigation of oscillation. Moreover, theoretical studies of the WBG switching performance and switching oscillations are performed based on spectrum analysis. The mathematical derivation reveals that the oscillation tends to enhance certain regions in the electromagnetic interference (EMI) spectrum by inducing a noise peak. In addition, modeling and analysis of silicon carbide (SiC) MOSFET switching oscillations are presented by developing equivalent circuit models for the turn-on and turn-off switching, respectively. Damping techniques design guidelines are provided based on the modeling analysis. Last but not least, a new technique to accurately characterize the parasitic inductances of power devices in discrete and module packages based on two-port scattering (S) parameters measurement is proposed. The approach is first verified with high frequency circuit simulation and then experimentally validated through case studies of a number of discrete devices and power modules. Ph.D. in Electrical Engineering, May 2018 Show less
