Current Harmonics Controller for Reduction of Acoustic Noise, Vibrations and Torque Ripple Caused by Cogging Torque in PM Motors under FOC Operation

Martin Sumega,Pavol Rafajdus,Marek Stulrajter

doi:10.3390/en13102534

Abstract

This article presents an effective algorithm to reduce acoustic noise, vibrations and torque ripple caused by cogging torque in three-phase Permanent Magnet (PM) motors under Field Oriented Control (FOC) operation. Cogging torque profile is suitably included into q-axis current reference, which must be then precisely tracked in order to mitigate acoustic noise, vibrations, torque ripple and speed ripple caused by cogging torque. Conventional FOC structure has been extended by a Current Harmonics Controller (CHC) to achieve precise control of dq current harmonics for all operation speeds, which is crucial to reduce impact of cogging torque and increase performance of electric drive with PM motor. Effectiveness of proposed control technique is experimentally verified by vibrations and acoustic noise measurements.

Highlights

High-performance robotic applications, some automotive applications or home applications require smooth torque, low vibrations and quiet operation
Harmonic magnetic forces caused by cogging torque generate radial vibrations in the stator, which results in undesirable vibrations and acoustic noise in medium-low power Permanent Magnet (PM)
Authors of this paper have focused on the control strategies for the identification of cogging torque in PM motors and for reduction of speed ripple by tracking the cogging torque profile, where limits of conventional method for cogging torque reduction are presented [17]

Summary

Introduction

High-performance robotic applications, some automotive applications or home applications require smooth torque, low vibrations and quiet operation. Low-cost PM motors used in this kind of applications can significantly decrease operation quality and comfort of the users. Price reduction in industry leads to more frequent use of low-cost PM motors with simple and low construction quality. Harmonic magnetic forces caused by cogging torque generate radial vibrations in the stator, which results in undesirable vibrations and acoustic noise in medium-low power PM motors [1,2,3,4,5]. Undesirable impact of the cogging torque on the performance of the PM motor can be suppressed by modifications in the motor construction [7] or by current injection [8,9]

Methods

Results

Conclusion