Topology Optimization of Electrical Machines for NVH Purposes in E-mobility Applications - Part 1

This paper presents a topology optimization method for reducing specific stator tooth force harmonics which may be considered critical for noise reduction of traction motors designed and developed for e-mobility applications. A design proposal developed for performance and efficiency was analyzed with regards to stator tooth force excitation. The tooth force data was then used to calculate the acoustic power generated by the considered motor. The methodology for the CAE predictions was correlated with measurements. Analyzing the calculated and measured noise radiation from the traction motor, it was found that the overall noise level was dominated by mechanical tooth force order 48 and as a result, focus was put on this harmonic in particular. In order to address the issue, topology optimization was carried out on the rotor barriers of the designed motor with the aim of reducing tooth force order 48, while keeping the other harmonics within the limit. The design output of the topology optimization carried out showed significant reduction in the radiated acoustic noise with minor impact on the motor performance, in the range of 1 percent.