Thermal Evaluation of a Short-Operating-Duty Dual-Lane Fault-Tolerant Actuator for Aerospace Applications

This article presents design considerations for a short-operating-duty, fault-tolerant actuator for aerospace applications, with the research focus placed on thermal management. A fully enclosed and naturally ventilated permanent magnet (PM) synchronous machine with a dual-lane modular stator-winding topology is analysed. The aim is to assess alternative solutions for satisfying both sufficient heat removal and simple and robust machine construction design targets. The thermal management is particularly challenging because there are limited means for an effective heat removal from the machine body. Selected design choices impacting the machine's thermal behaviour, including alternative electrical insulation systems, winding impregnation quality, thermal contact interfaces and different winding and housing configurations are investigated. A three-dimensional (3D) transient finite element (FE) analysis has been carried out alongside an experiment informed low-order thermal network sensitivity evaluation. The theoretical body of work has been supplemented with thermal tests on an array of motorettes fabricated using alternative electrical insulation systems. The theoretical and experimental findings suggest that the winding impregnation quality has a dominant impact on the actuator's thermal behaviour, where both heat removal path (thermal resistance) and heat storage (thermal capacitance) need to be well balanced for the short-duty transient operation under a faulted condition.