Electrical Machine Design Considering Corona-Resistant Wire for More Electric Aircraft Applications

Higher dc link voltage and shorter rise time keep challenging the insulation system of inverter-fed low-voltage electrical machines (EMs). In more electric aircraft (MEA) applications, the low-pressure working environment faced by EMs further increases the risk of partial discharge (PD) endangering the electric drive reliability. Through an additional inorganic insulation layer, corona-resistant (CR) wires reveal the ability to withstand PD and represent a potential solution for aerospace applications. In this article, a CR wire is characterized, and its performance is compared against that of a non-CR (NCR) counterpart in the perspective of PD inception voltage (PDIV), electrical endurance, and thermal properties. A starter/generator (S/G) is considered as a study case to highlight the influence of machine design when CR is employed. Two machine designs, each using CR and NCR wires, are presented and analyzed in terms of rated current, copper slot fill factor, and reliability performance (PDIV and lifetime extension).