Lifetime estimation of corona-resistance wire for electrical machines operating under the partial discharge regime

The trend towards higher onboard DC link voltage keeps increasing the partial discharge (PD) risk of electrical machines (EMs) for more electric aircraft (MEA) applications. Compared to the traditional Type I insulation, the corona-resistant (CR) wire with an additional inorganic layer boosts the lifetime of EMs under the PD regime and enables the design of EMs capable of safely operating at higher DC bus voltage. In this paper, the lifetime of CR wires operating under the PD regime is estimated. A starter/generator meant for more electric aircraft applications is selected as the study case, whose windings employ CR wire. The partial discharge inception voltage and electrical endurance are experimentally determined, and the lifetime model is built based on the collected results. Then, the starter/generator lifetime is estimated by considering both operating conditions and electric drive parameters.