Modelling and simulation of electromagnetic audible noise generated by traction motors

An annoying tonal noise is produced by modern electrical trains during acceleration and deceleration. This noise is caused by electromagnetic forces generating structural vibrations, especially from the traction motors. The electromagnetic noise is dominant at low train speeds and affects both the passengers on the train and on platforms, as well as people living near the track. The focus on this issue has increased the last years, both regarding legislation, contractual requirements and also because of expectations from citizens and travelers. To be able to design low noise electric drive systems, a thorough understanding of the cause and the possibility to predict the electromagnetic noise is needed. This thesis describes the modelling and simulation of an complete multi-physics real-time environment for prediction and analysis of the electromagnetic noise. The simulation results are validated against measurements of the structural vibration and acoustic response of a real traction motor fed by a power converter running in the entire operational range.