Performance Evaluation of Insulation Designs for Rotating Machines in More Electric Aircraft

The increasing dc bus voltage and reduced rise times experienced in aeronautical environments present significant challenges to the insulation systems of rotating machines. These conditions can generate elevated overvoltages, raising the risk of partial discharge (PD) in the insulation of inverter-fed motors utilized in more electric aircraft (MEA). Therefore, the design of the insulation system is critical in MEA development, as it is essential for ensuring safety and reliability. This study investigates the degradation of PD inception voltage (PDIV) and PD extinction voltage (PDEV) in enameled rectangular wires commonly used in rotating machines. The experiments were conducted under conditions of high temperature and low air pressure. Additionally, we compared the performance of corona-resistant (CR) and non-corona-resistant (NCR) materials, both of which have the same specifications, during endurance tests at low air pressure. The results indicate that PD events are more likely to occur under aeronautical conditions, and the use of CR materials at low air pressure poses significant challenges. Finally, we evaluated the performance of two novel insulation designs for MEAs to assess their applicability and limitations for operational use in aeronautical environments.