Active PMSM acoustic noise reduction through multiphysics modal optimization

This paper presents a generic frequency-domain optimization based approach for calculating harmonic currents that can be injected in a PMSM to improve acoustic performance. In contrast to other methods, the presented approach minimizes sound instead of stress and considers all spatial modes. A semi-analytical multiphysics model is established that relates winding current harmonics with radiated sound. Regularized complex optimization is used to find the amplitudes and phases of current harmonics that minimize radiated noise considering all temporal and spatial modes. The approach is verified using a semi-analytical model and numerical simulations for an exemplary 12 pole 36 slot (12P36S) motor. Results show a noise reduction of up to 17dB.