Lifetime Prediction of Low Voltage Electrical Machines Based on Accelerated Aging Tests Under Periodic Temperature Profile

Low-voltage electric machines (EMs) with high power density and compact volume represent the key target in transportation electrification. In order to safely carry out the designated mission profile throughout the life service, the EM should be conceived according to an appropriate trade-off between reliability and performance. Although the over-engineering of the electrical insulation ensures the reliability requirements, its adoption compromises the EM performance. Therefore, a shift towards physics of failure (PoF) methodologies applied to electrical insulation is often preferred to fulfill the demanded reliability standards, while achieving optimal performance. In literature, constant temperature thermal aging is often considered in EMs' design, although most EMs experience a variable temperature profile during their operations. Thus, in this paper, the accelerated thermal aging tests are performed at variable temperatures employing three periodic temperature profiles (TPs) and lifetime is predicted based on test results. Finally, a reliability assessment is conducted to achieve a more comprehensive EM design.