Aircraft Insulation Design for the More Electrical Aircraft: Challenges and Solutions

This paper considers the design options to achieve the reliability of random-wound motors fed by silicon carbide inverters and used for the More Electrical Aircraft (MEA). Considering the inception of Partial Discharges as the most severe degradation process, the Partial Discharge Inception Voltage (PDIV) of non-impregnated and impregnated twisted pairs was measured feeding the twisted pairs with a silicone carbide inverter in a partial vacuum. The results show that the margins to ensure that partial discharges are not incepted during operation are tight and that switching to multilevel inverters and hairpin geometries might be necessary if the DC bus voltages will be raised above the current levels (±270 V).