More reliable aircraft electric drive
More-electric aircraft is an emerging design concept on the road to future all-electric aircraft. Owing to their huge potential to reduce the aviation industry’s carbon footprint, fail-safe machines are attracting special attention. Slow degradation of the motor windings insulation system over time has been reported to be one of the most common causes of machine failure. Gaining further insight into insulation degradation mechanisms will help machine design become much more sophisticated. Moreover, by simplifying machine design it will be possible to reduce the weight of more-electric aircraft without offsetting any savings offered by higher efficiency or sacrificing reliability. Within the EU-funded project ALEA (Accelerated life tests for electric drives in aircrafts), researchers successfully developed a test rig that can validate ageing models by applying multiple age-accelerating stresses and conduct online tests of the machine drive under different operating conditions. In particular, the newly developed system investigates the effects of four major stress sources on motor windings insulation, namely thermal, ambient, electrical and mechanical. It comprises four main components: a thermal vacuum chamber for applying different stress types; a reconfigurable test bench; a data acquisition and control system for monitoring relevant operating parameters; and a custom inverter to drive the motor under test while applying different stress levels. Other than combined ageing stresses, the test rig can also replicate various mission profiles representative in real flight: temperatures can range from -40 to 180 °C and pressures can range from 30 to 1 000 mbar. ALEA’s new-generation test rig enables improving machine design methodologies that should mitigate the risk of insulation degradation. In addition, project outcomes will greatly benefit European motor and drive manufacturers, helping them to improve their products and become more competitive worldwide.
