Analysis on Noise Source of Claw Pole Machine in Belt-driven System

The acoustic noise generated in a belt-driven integrated starter and generator (BSG) is recent issue. By many studies, it has been known that the noise can be caused by both radial and tangential components of an electro-magnetic force. A six-phase claw pole machine is widely used for the BSG. In this case, due to its structural feature and experimental condition, additional noises at frequency can be generated. In this paper, a method to analyze the noise source of a prototype which is the claw pole type machine designed for the BSG was proposed. First, the electromagnetic force was calculated by a finite-element analysis considering the unbalanced current. The obtained force was decomposed according to the frequency and then analyzed. Through the harmonics of the force, an additional noise according to the frequency, which is generated because of the unbalanced claw shape in the axial direction and current imbalance between phases, was deduced. Finally, the experimental validation was conducted.