Frequency-Band Analysis for Acoustic Noise Characterization of an Interior Permanent Magnet Motor

The analysis of acoustic noise characteristics is important for effective noise reduction. This paper presents a computationally efficient approach for acoustic noise analysis of an interior permanent magnet (IPM) motor. A combination of surface velocity results calculated using ANSYS are coupled with AVL EXCITE Acoustics to estimate the air-borne noise produced by the motor. The air-borne noise is calculated using the Wave Based Technique (WBT) instead of an element-based technique such as Finite Element Analysis (FEA). The WBT requires less fine element discretization which results in smaller numerical models. The WBT mesh is generated by an automated process and merged to reduce the number of elements for optimizing the computational performance. The acoustic noise analysis for this motor includes the characterization of frequency band analysis including the narrow band, octave band, and third octave band air-borne noise calculated by the WBT-based approach. The characteristics of the generated air-borne noise for this motor are analyzed and presented. High sound pressure level (SPL) due to dominant harmonic frequencies and natural frequency excitation is explained.