A Systematic EV Bearing Degradation Testing Approach Considering Circulating Bearing Currents

Bearings are critical components in the motor drive systems of electric vehicles (EVs), and their degradation results in reduced efficiency and increased vibration, thereby compromising operational safety. With the widespread adoption of electrification and variable frequency drive technologies, electrical corrosion has become a significant concern. Nevertheless, most existing bearing degradation testing methods target the mechanical loads with less focus on electrical loads, especially the circulating bearing current dominant in high-power EV motor drive systems exceeding 100 HP. This article proposes a systematic EV bearing degradation testing approach considering circulating bearing currents. A novel test platform is designed to impose controlled circulating bearing currents and emulate the real-world environment. Applying the collected vibration data, a dedicated status quality index is defined to quantify the health condition of the bearing under test.