Characterisation of radial vibration force and electromagnetic noise behaviour of a PWM-fed permanent magnet synchronous machine

This paper presents the full analysis of the radial forces behavior responsible for audible magnetic noise in a PWM-fed permanent magnet synchronous traction machine with surface permanent magnet. Magnetic force waves due to slotting harmonics, pulse-width modulation (PWM) are characterized for different speeds, including theoretical predictions and experimental validations. The coupled lumped multi-physics models are developed in order to compute stator current, the radial air-gap flux density, the radial forces and the audible magnetic noise. Finally, some simulations and experiments are compared for many points of the electrical traction characteristics: output torque versus speed.