Electromechanical actuator fan failure analysis and safety-critical design

• Published in: IEEE aerospace and electronic systems magazine 2017-04, Vol.32 (4), p.18-25
• Main Authors: Wu, W., Lin, Y. R., Chow, L. C., Gyasi, E., Kizito, J. P., Leland, Q. H.
• Format: Magazinearticle
• Language: English
• Subjects: Acceptability; Actuation; Aerospace electronics; Air cooling; Air safety; Aircraft; Catastrophic failure analysis; Convection cooling; Cooling systems; Design analysis; Design engineering; Electronic devices; Failure analysis; Fault diagnosis; Fault tree analysis; Feasibility; Flux density; Heat; Heat generation; Heat transfer; Heating systems; Management; Missions; Motors; Product design; Reliability; Safety; Stator windings; Waste heat
• ISSN: 0885-8985; 1557-959X
• DOI: 10.1109/MAES.2017.150281

The aim of this study is to use fault tree analysis to gain a better overall understanding of how to improve the reliability of a fan cooling system used to prevent electromechanical actuation systems (EMAs) from overheating. It is critical to manage the waste heat generated by EMAs on aircraft during all flight missions because EMA failure due to overheating could lead to an aircraft catastrophic failure. Heat generation by high-power-density power electronic devices and EMA motors has reached a heat flux density that thermal management of EMA by natural convection is not feasible, forced air cooling is needed. Since EMA motors and power electronic drives must operate at various altitudes and temperature throughout a flight mission, there is a need to develop a variable-speed fan that can operate efficiently and reliably over a wide range of pressure and temperature. To prevent EMAs from overheating and bring EMA failure probability to an acceptable level, a sturdy cooling fan which can operate under variable body forces due to aircraft maneuvering is required.