Study of Inverter Topologies for Electrified Aircraft Propulsion Systems Based on Cyclic Loading Induced Bond Wire Fatigue

This paper presents a comparative analysis between the Two-Level Voltage Source Inverter (2L-B6) and Three-Level Active Neutral Point Clamped Inverter (3L-ANPC) configurations tailored for short-haul aircraft applications. Based on a six-phase, two-level prototype of an aircraft drive inverter, the study compares lifetimes based on bond wire fatigue. This study is supplemented by own accelerated aging tests on SiC-multichip modules for the identification of lifetime model parameters. Due to the absence of dedicated all-SiC modules for the 3L-ANPC topology in that power class, modules similar to those in the prototype but with reduced voltage ratings and increased current ratings are utilized. This analysis demonstrates that the switches in the 3L-ANPC topology show an up to 19.32 times higher anticipated lifetime compared to its 2L-B6 counterpart. Furthermore, increasing the switching frequency from 16kHz to 32kHz significantly reduces the lifespan of the 2L-B6 inverter to 11.78 % compared to the initial value. Conversely, the 3L-ANPC configuration operating at 32kHz still exhibits an up to 2.97-fold increase in lifespan compared to the baseline 2L-B6 at 16kHz.