On the Use of Vibration Synthesis to Ease Electric Machine Powertrain Design

Abstract

This paper provides e-machine designers a critical study on the vibration synthesis algorithm that calculates the vibrations of an electric machine responsible for magnetic noise. It separates the computations into two distinct categories: offline and online. Comprehensive parameters are input to an offline simulation system where generic magnetic forces and vibration transfer functions are created. This generic data combined with operational loads from system-level simulations refers to the online simulation environment. The methodology is applied to an interior Permanent Magnet Synchronous Machine (PMSM), and compared to the standard procedure where run-up simulation can become time-expensive due to the extensive use of Finite Elements (FE) methods. Vibration results show discrepancies of harmonic amplitude content essentially coming from the force truncation made in the vibration synthesis, for which a selection protocol is proposed. Yet the offline simulations permit to frontload the computational efforts thus implying the use of the technique in system-simulation environments.

PMASynRM late design-stage rotor shape NVH optimization

“…(1) The vibration is calculated numerically in Simcenter 3D as the superposition of dynamic responses excited by each significant force shape. This is achieved with a modal frequency response solution, having the excitation F [I],shape a unitary force shape where the total energy per frequency line is equal to 1 N [12]:…”

PMASynRM system-level NVH model with eccentricity

“…The vibration synthesis uses the superposition of dynamics responses for each important excitation force shape component [2]. This is achieved by using a modal frequency response solution, where the excitation F [I],shape is a unitary force shape with energy conservation properties -the total energy per frequency line equal to 1 N [13]:…”

Comparative study between PMSM models used for NVH system-level simulation

“…Fourier series decomposition is applied to the radial force to isolate the spatial and the rotor position dependent components. This procedure allows to simplify the analysis within SL model simulation and it is performed for each operating point following [3], [8]:…”

“…This, essentially results from the multi-physical characteristic of noise and vibrations (control, structural dynamics, electromagnetics). Previous work on the SL simulation approaches can be found on [2], [3].…”