Acoustic noise in inductive power components

This paper deals with the acoustic emissions of PWM-operated inductive components in the medium frequency range. It is shown with measurements that the noise emissions are primarily caused by magnetostriction, an induction-dependent dimensional change of the magnetic core. The influences of various modulation parameters on the sound pressure level spectra of two prototypes are measured and analyzed. It is confirmed that the emitted sound is proportional to the square of the magnetic flux density.