Vibro-acoustic measurements and techniques for electric automotive applications

In this study, noise and vibration measurements were carried out on a multi-phase 12/8 switched reluctance (SR) motor and analyzed with vibro-acoustic techniques. When evaluating the behavior of electric powertrains for automotive applications, it is necessary to perform a vibro-acoustic analysis, particularly in view of the acoustic comfort perceived by the driver and passengers. High frequency tonal noise can be very annoying and even causes long term damage. Therefore, the noise and vibrations must be deliberately optimized. In case of a SR motor, the radial magnetic forces between the stator and rotor are the main excitation source, yielding large deformations of the stator housing and emissions of noise. Measurements and simulation results are compared for different load conditions. The dominant vibration modes are analyzed with modal analysis techniques. The unpleasant tonal noise of the motor is objectively quantified by noise metrics. Finally, the relationship between the current profiles, radial magnetic forces, and mechanical and acoustical vibrations is investigated in order to obtain a better understanding of the mechanisms underlying the vibro-acoustic behavior of the motor.