Vibroacoustic Models of Air-Core Reactors

Abstract

The purpose of this paper is to provide an overview of the sound power radiation mechanism of air-core reactors and to describe the method that is used to calculate sound power by using the electrical load. Sound power radiation of an air-core reactor is related to the alternating current harmonics, the mechanical tension stiffness and, most importantly, the breathing mode resonance. An analytical model that is based on electrical loads and mechanical properties of the air-core reactor is developed to calculate radial and axial forces caused by the radial and axial magnetic induction fields. This study employs the hemispherical spreading theory, which is a simple and common method that is used to predict sound propagation. Additionally, a numerical model is proposed. In this, the excitation of the acoustic field that surrounds the reactor is introduced by considering the radial and axial displacements of the reactor's windings, as the windings are subjected to the action of the radial and axial electromagnetic forces. Finally, a comparison is presented between analytical and numerical models and it is observed that the models are correlated.