Optimal Design for Noise Reduction in Interior Permanent-Magnet Motor

This paper presents methods to reduce acoustic noise in an interior permanent-magnet motor during the design stage. Mechanical and magnetic sources are considered to reduce noise of the machine, and structural and electromagnetic designs are performed. In the structural-design stage to reduce mechanical source, the structural resonances are moved to higher frequency for enhancement of stiffness. Then, in the electromagnetic-design stage to reduce exciting forces, the harmonic amplitude of magnetic forces and torque ripple are reduced by using an optimal design method, respectively. Two models are designed according to each objective function, and the validity of the design process and objective functions is confirmed by their simulated and experimental results.