Mission Profile-Based ANPC Inverter Design Aspect and Reliability Analysis

Electric aircraft require efficient, power-dense, and reliable propulsion inverters. The choice of the inverter topology is crucial, with the 2-level VSI and the 3-level ANPC inverter being the most discussed. The advantages of the ANPC, however, are overshadowed by concerns about its reliability due to increased complexity. In this work, mission profile-based investigations are performed for the inverter of an exemplary short-haul aircraft. The power device junction temperatures for different design choices are derived, followed by a reliability analysis incorporating experimentally obtained lifetime data. Freedoms in ANPC design were effectively used to influence power loss and junction temperature over the mission profile, positively affecting efficiency and the required cooling effort and, furthermore, increasing the lifetime of the power semiconductors and the reliability of the converter.