NVH analysis of a 3 phase 12/8 SR motor drive for HEV applications

In this study different noise and vibration measurements on a multi-phase 12/8 switched reluctance (SR) motor for automotive applications are carried out on a test rig and analysed with vibro-acoustic techniques. When evaluating the behaviour of rotating machinery for HEV applications, it is necessary to perform a vibro-acoustic analysis. The reason for this is that these specific noise and vibration contribute significantly to the perceived overall sound quality in the passenger compartment and outside the vehicle. Vibrations or high frequency tonal acoustic noise could be annoying for the passengers or could even cause long term damage. Therefore, the noise and vibration must be deliberately optimized. In case of a SR motor, the radial magnetic force between stator and rotor is a main excitation source to create large deformations of the stator housing, causing serious vibrations and acoustic noise. Measurements and results of simulations in different load conditions are compared. In addition, the dominant vibration modes are verified by modal analysis and operational deflection shapes. The unpleasant tonal acoustic radiation of this electric motor is objectively quantified by noise metrics. Finally, the relationship between the current profiles, radial magnetic forces, and mechanical and acoustic vibrations is investigated to obtain a better insight into the root cause of the vibro-acoustic behaviour of the motor.