Electric Potential Distribution in Three-Phase Windings under Pulse Voltage Stress

This research presents a novel method for predicting the potential distribution in electrical machines with random-wound windings under pulse voltage stress. A non-uniform potential distribution is caused by several factors including the introduction of fast-switching power semiconductors, continued improvements in power module design, the need for higher efficiency, and the integration and downsizing of components in new fields of application, such as electric vehicles and all-electric aircrafts. The contribution is summarized by answering key research questions, including the need for a distributed equivalent circuit network to capture the high-frequency behavior of the electrical machine, the use of Monte-Carlo calculations to account for parameter uncertainties, and modeling the distribution of conductors inside a stator slot using probability density functions. The investigations into the driving factors for non-uniform potential distributions indicate that the winding-to-stator capacitance and the presence of ohmic losses in the winding and stator iron play a significant role.