Noise-Vibration-Harshness-Modeling and Analysis of a Permanent-Magnetic Disc Rotor Axial-Flux Electric Motor

A drive-system-based modeling approach for electromagnetically excited noise-vibration-harshness (NVH) simulation of a disc rotor permanent-magnetic axial-flux synchronous motor is introduced. The electric motor type requires a 3-D finite-element (FE)-based modeling for electrodynamics and magnetomechanical coupling. The methodic focus relies on orthogonal 3-D Fourier-representations for structural modal displacements and for magnetic force densities. The application of Galerkin-projection based on a supermesh construction between source FE meshes to equidistant 3-D grids is hereby required. A significant data reduction for model parametrization is achieved and a low-rank domain coupling matrix, including a high technical interpretability, is derived. Thus efficient NVH simulations of operation cycles including inverter and control influences can be performed within an order-reduced formulation. This paper is the first to derive a fully 3-D FE-based NVH analysis workflow for electric machines under realistic operating conditions for a routine industrial applicability. The high validity of the methodology is proven by a good agreement to real world measurements.