Reliability Considerations for Large Spacecraft Propulsion System

This paper delves into the development of a power conversion scheme suitable for MW-scale Electric Propulsion (EP) systems deployed in large spacecraft. The proposed scheme involves a multiphase dual rotor generator (DuRG) and a multiphase multilevel (MPML) power electronics converter integrated with the spacecraft's DC bus. One of the primary objectives is to design a control scheme for the MPML converter that optimally utilizes the available DC voltage, ensuring compatibility with the EP thruster's characteristics. Unlike traditional three-phase multilevel converters, MPML converters offer advantages such as enhanced control, higher power density, improved fault tolerance, reliability, and energy accessibility. The study investigates the reliability of various power electronics components, conducts converter-level reliability assessments, and examines the impact of different control schemes on overall reliability. The paper introduces the MPML-SVM technique, utilizing space vector modulation (SVM) for generating switching states and reference voltages. This research contributes valuable insights into power conversion for MW-scale EP systems and paves the way for more efficient and reliable spacecraft propulsion technologies.