Common mode voltage impact on wind turbine main shaft bearing

Paper in proceeding, 2021

Main shaft bearing is a critical component in the wind turbine rotating system. But the bearing voltage, which is generated by the potential differences between the bearing and the main shaft, often causes the downtime of the main shaft bearing. The potentials are induced by multi-physical phenomenon, such as fast-switching power electronics interference and electrostatic charge accumulations, may cause damages on bearing and electromagnetic interference (EMI). Base on the field test result of the bearing current, common-mode voltage (CMV) of the converters is considered as the main source during normal operation. In this paper, a circuit model is proposed to study the two different CMV transmission path to the main shaft bearing and a downsized wind turbine is built and tested in lab environment to verify and improve the model.