Analysis of the Sideband Electromagnetic Noise in Permanent Magnet Synchronous Motors Generated by Rotor Position Error

In this article, the influence of the rotor position error generated by the resolver on the electromagnetic noise of permanent magnet synchronous motors (PMSMs) is analyzed. The motor noise is mainly caused by the electromagnetic force acting on the surface of the stator teeth or permanent magnets. First, the influence of the rotor position error on current harmonics is deduced theoretically. The spatial and temporal characteristics of the electromagnetic force are then analyzed. The results show that the rotor position error will introduce extra sideband frequency harmonics to the current and electromagnetic force. This will lead to more abundant noise harmonics. The field-oriented control model and the electromagnetic finite-element model are then established to simulate the influence of the rotor position error on current harmonics and electromagnetic force. Finally, a test is carried out to capture the phase current and noise spectrum. Both the simulation and test results are consistent with the theoretical analysis results. This study can give a reference to the source identification and optimization of acoustic performance for PMSMs in electric vehicles.

I. Introduction

Permanent magnet synchronous motors (PMSMs) have been widely used in electric vehicles due to their high efficiency, high power density, and wide speed range [1]. The driven motors replace the traditional internal combustion engines in electric vehicles and serve as the power assembly. This leads to the motors one of the main sources of acoustic noise for electric vehicles. The sound pressure level (SPL) of electric motors is relatively lower than that of internal combustion engines. However, its frequency is higher and distributed in the sensitive frequency band of the human ear, which leads to poor subjective feeling. The study of electromagnetic noise of PMSMs is of great significance for the improvement of vibroacoustic quality and comfort for electric vehicles.