Improving Onboard Converter Reliability for More Electric Aircraft With Lifetime-Based Control

Abstract

With the goal to decrease weight and increase overall efficiency, power electronics is proliferating in the aircraft applications. The conventional mechanical, pneumatic, and hydraulic systems are substituted with on-board electrical distribution systems. The new power electronics based distribution architectures should comply with the airworthiness standards by providing adequate redundancy to operate even under multiple failures. However, each redundant system adds to more weight and cost, and hence optimizing redundancy without compromising safety still remains a challenge. In this scenario, modular power converters offer a promising solution for obtaining reliable operation. Apart from ensuring availability and operation of the system, the modular converters enable controlling the stress for the individual converter cell and therefore their wear-out. This paper considers the failure mechanisms of the most sensitive devices in the system, the power semiconductors, and predicts their remaining useful lifetime (RUL). Based on this RUL, an optimization of the system loading is performed in order to delay the wear-out based failures in the system without reducing the mean lifetime of the building blocks. A study case is shown in order to demonstrate the lifetime extension of the system with the proposed algorithm.