FPCB Hybrid Shield-Based Method for Integrated Shaft Voltage Reduction and Fault Diagnosis

Recently, with the advancement of high-performance electric vehicles (EVs), there has been a growing trend toward high-voltage battery systems. As a result, while the performance of EVs improves, the risk of bearing electrical erosion faults due to shaft voltage in motors also increases. The occurrence of bearing electrical erosion faults causes cracks in the balls, inner race, and outer race of the bearing. Additionally, when damage occurs to the bearing that supports the rotor shaft of the motor, dynamic eccentricity faults or static eccentricity faults may additionally occur. Bearing electrical erosion faults caused by shaft voltage, as well as eccentricity faults caused by bearing damage or motor assembly, can lead to serious vehicle faults. Therefore, this study proposes a flexible printed circuit board (FPCB)-based hybrid shield to reduce shaft voltage in motors and prevent bearing electrical erosion faults, and also to diagnose bearing or eccentricity faults at an early stage when they occur. To verify the reliability of this study, experimental validation was conducted with a focus on practical demonstration.