Investigation of Vibration and Acoustic Noise Emission of Powder Core Inductors

In power electronics applications, where the switching frequency is below the audible frequency, the design of magnetic components considering acoustic noise and vibration is as important as designing for efficiency. For the case of the powder core, which is widely used in grid-connected inverters, much research has been conducted in terms of efficiency and core loss. However, there has been limited research dealing with the topic of acoustic noise and vibration. In this paper, Sendust (Fe-Si-Al), MegaFlux (Fe-Si), and HighFlux (Fe-Ni) powder core materials, which have low magnetostriction and low core loss, are analyzed in terms of acoustic noise induced by Maxwell force and magnetostriction. Three types of powder core materials having a rectangular shape are designed for a 4-kW grid-connected inverter. Various building structures, such as rectangular, toroidal, and oval-shaped, for a Sendust core are compared with sound pressure level and efficiency. The effects of the magnetic flux density, Maxwell force, and magnetostriction are analyzed using the finite element method and are verified experimentally. In addition, the experimental results of sound pressure and inductor efficiency are presented according to core materials and building structures.