Simulation Diagnostics Approach for Identification, Ranking and Optimization of Electric Motor Design Parameters for Optimal NVH Performance

With increasing efforts towards rapid electrification of powertrains, NVH engineers face new set of challenges. Elimination of the IC engines drastically reduces powertrain borne noise levels but unmasks other existing noises like wind, road, ancillary devices, and squeak & rattle. In addition, the new tonal sounds from electro-mechanical drive systems makes the noise more annoying even though it is lesser quantitatively. In summary, the electrification of powertrains has shifted powertrain NVH development from overall level to sound quality with different targets requiring several electro-mechanical solutions with innovative simulation, testing, and optimization approaches. The purpose of the paper is to present an approach to detect, quantify, and optimize the structure-borne radiated noise of an electric motor due to electromagnetic forces or maxwell pressure exerted by magnetic effects in electric motor. The Maxwell electromagnetic excitations are computed and applied on the stator structural mesh to compute the radiated noise using vibroacoustic simulations. A diagnostic approach is established to investigate the individual and interactive effects of Maxwell forces and structural modal behavior of the electric motor on the radiated noise characteristics. The interpretation from these diagnostics results are used to identify, rank, and optimize motor design parameters contributing in NVH responses in addition to structural modifications on the motor radiating surface.