Numerical prediction and analysis of electromagnetic vibration and noise of claw pole alternator

Abstract

A complete methodology for electromagnetic vibration and noise prediction of claw pole alternators is presented. It is a 3-step multiphysics simulation. The first step is to calculate the distributed magnetic force exerted on the inner surface of the stator using 3D FEM. The second step is the structural analysis which is to investigate the natural resonant frequencies and modal shapes of the alternator system taking into account the real mechanical boundary conditions. The third is the electromagnetic vibration and noise calculation by using modal superposition method and boundary element method respectively. The modeling can ensure the temporal and spatial distribution characteristics of the electromagnetic force and reflect the structural mechanic characteristics of claw pole alternators. Simulation results agree well with those measured by experiments. Furthermore, the mechanisms of electromagnetic vibration and noise are analyzed by using the electromagnetic theory. The method can be used in the initial design stage of claw pole alternators and is also suitable for other type of motor.