Master of Science, The Ohio State University, 2021, Electrical and Computer Engineering

Advancements in semiconductor technology present new challenges in electric machine construction, operation, and control. Silicon carbide (SiC)-based power electronics are becoming the new standard for high-power consumer and commercial devices, and are implemented in technologies such as power inverters, converters and rectifiers. This paper focuses on the effects of inverter drives for traction motors in electric vehicles with high dV/dt rates on bar-wound machine windings, including the expected impacts on insulation materials under prolonged periods of high voltage stress. Partial discharge inception voltage testing was performed to evaluate the voltage bus level at which breakdown will start to occur. A simulation model was constructed using finite element analysis, the results of which were validated with experimental results using a commercially available SiC inverter and traction motor. Correlation has been established between the preliminary simulation results and experimental data. It is proven that as DC bus voltages increase with the capabilities of SiC devices, the voltage stresses inside the stator windings approach levels which could cause partial discharge and premature insulation degradation in existing stator designs.

Committee: Julia Zhang (Advisor); Jin Wang (Committee Member) Subjects: Alternative Energy; Design; Electrical Engineering; Electromagnetics; Electromagnetism; Energy; Engineering; Solid State Physics; Sustainability; Transportation