Simplified Analytical Algorithm of Motor Noise Waterfall Diagram Based on Sensitivity Analysis of Structural Parameters

The noise of the motor is one of the important issues to be considered in motor design, which affects the performance of the motor and the user experience. Now the widely used noise analysis method is to simulate the motor noise waterfall diagram in the software to obtain the noise at different frequencies and speeds. But this method is very time-consuming, especially when repeatedly modifying parameters to reduce noise. Therefore, a simplified analytical algorithm of waterfall diagram based on sensitivity analysis of structural parameters is proposed to predict noise. Firstly, the sensitivity of structural parameters to electromagnetic force is obtained by optiSLang software, which provides a basis for parameter screening. Then, the selected parameters are fitted with each order of electromagnetic force in the Design-Expert software. The fitting formula is accurate enough to predict the value of each order of electromagnetic force. Next, the natural frequencies of each order of motor vibration are obtained in ANSYS Workbench, and then the motor noise at different speeds and frequencies could be calculated. In order to form a clear, systematic approach, the software program for predicting each order of electromagnetic force and displaying the simplified noise waterfall diagram is written based on Python. Compared with the values of each order of electromagnetic force and the complete waterfall diagram obtained by simulation, the calculation error of the software program is within the allowable range. The key characteristics of motor noise could also be reflected in the simplified waterfall diagram, which verifies the efficacy and rapidity of this method.