NVH Optimization Analysis of Permanent Magnet Synchronous Motor by Rotor Slotting

Abstract

With the development of new energy vehicles, the NVH (Noise, Vibration, Harshness) performance of the permanent magnet synchronous motors (PMSM) for vehicles has attracted more and more attention. The rotor slotting optimization analysis is the critical issue in the NVH performance study of PMSM. In this paper, the theoretical formula of the PMSM radial electromagnetic force is presented. Based on which, the spatial order and frequency order characteristics of the radial force of a 6-pole 36-slot PMSM are analyzed. Firstly, electromagnetic simulation of the motor is carried out, and the specific force components, which may cause an NVH problem, is extracted. Secondly, the harmonics are calculated with a method of freezing the relative magnetic permeability. Thirdly, the motor is optimized by rotor slotting to reduce the amplitudes of these harmonics, and the effect on electromagnetic noise is analyzed in theory and simulation. Finally, the NVH test in original state and after rotor slotting state was performed in the semi-anechoic chamber. The accuracy of the theory and simulation was verified based on the comparison of the measured noise data. This paper provides a new NVH optimization idea, this method can quickly locate the fundamental problem location of electromagnetic NVH, provide a fast channel for electromagnetic NVH optimization from simulation to verification, and improve the optimization efficiency of NVH.

High Efficient Permanent Magnet Synchronous Motor Design, Electromagnetic and Noise-Vibration Analyzes

“…Since electromagnetic forces cannot be eliminated theoretically and practically, minimizing these forces is very important for the life of the motor and driven load. Radial electromagnetic force density in the air gap according to the 'Maxwell Stress Tensor' equation (3) it is calculated from the formula [4]. Where θ is the angular position of the stator, t time, μ0 air gap magnetic permeability, air gap radial flux density .…”

“…Noise and vibration in these motors are examined under three main titles as electromagnetic, mechanical and aerodynamic as shown figure2. Especially in the electric vehicles, aviation and servo industry, the generation of noise and vibration have high importance [3,4,5]. Electromagnetic noise and vibration occurs when radial electromagnetic forces in the air gap effect on the stator teeth.…”

“…It is not possible to eliminate these forces, but these forces can be minimized. These forces cause the stator stack and the frame to be deformed over time due to the vibration effect [3,4,5].…”

NVH optimization of PMSM based on auxiliary slots in stator and rotor

“…Yang Y et al, reduced the harmonic distortion rate by setting a semicircular groove on the rotor, weakened the torque ripple, and improved the motor efficiency [5]. Wang Y et al, reduced the specific radial electromagnetic force that has a greater impact on vibration by setting arc grooves on the rotor, but the output torque has a certain reduction [6]. Li J et al, takes submersible motor as the research object.…”

Acoustic Signature Analysis and Sound Source Localization for a Three-Phase AC Induction Motor

“…EM simulation is imperative to predict radial and tangential forces in the air gap between the stator and rotor that cause the stator to deform and the housing to vibrate. Simulation models to analyze switched reluctance motors [5], permanent magnet motors [6,7], and induction motors [8] are already being developed. The forces from the EM simulation are used in acoustic and structural analyses to predict overall sound pressure levels (SPLs) from the motor and operating deflection shapes.…”